Unit One: Cell Biology.

Unit One: Cell Biology

National 4/5 Biology Course Unit 1
Units: Complete Life on Earth – mid Sept Cell Biology – Sept - Dec Multicellular Animals – Jan - April National 4/5 Biology Course Unit 1

How is the course assessed?
Course work: 3 end of unit tests (one for each unit) – can have resits if necessary One Practical investigation One mini research project (100 words) One LARGE research project (Added Value) ( words) NATIONAL 5 – Final exam! National 4/5 Biology Course Unit 1

Work Classwork to be done in jotter. Remember it every day! You will get set homework sometimes – but expected to learn the work done each day as you go along!!! National 4/5 Biology Course Unit 1

What is in Unit One? Cell Biology: Cell Structure Transport across membranes Producing new cells DNA and protein production Genetic engineering Proteins and enzymes Aerobic respiration Photosynthesis National 4/5 Biology Course Unit 1

1: Cell Structure

Cell structure LI: 1. Identify and name the structures found in an animal cell. 2. State the function of the structures in an animal cell. 3. Identify and name the structures found in an plant cell. 2. State the function of the structures in an plant cell. National 4/5 Biology Course Unit 1

Cell Structure Cells are the building blocks of all life. Cells video National 4/5 Biology Course Unit 1

Cell Structure We will be looking at 4 different cell types:- Animal cells Plant cells Bacterial cells, and Fungal cells. You have already looked at the basic structure of animal and plant cells in S1- S3. We will be looking at all of these cells in greater detail. National 4/5 Biology Course Unit 1

What can you remember from last year?
Task One: Complete the revision worksheet on cells. National 4/5 Biology Course Unit 1

Cell Structure Task 2: Prepare slides for examination under a light microscope. Using the help sheets provided prepare one type of slide – cheek cell, onion cell or Elodea pondweed. After you have examined your own slide share your slide with a group that has prepared a different slide . You should look at all 3 cell types. National 4/5 Biology Course Unit 1

Cheek Cells These are cheek cells viewed at 100x magnification using a light microscope. National 4/5 Biology Course Unit 1

Onion Skin Cells These are onion skin cells viewed at 40x magnification using a light microscope. National 4/5 Biology Course Unit 1

Elodea Pondweed Cells These are Elodea pondweed cells viewed at 100x magnification using a light microscope National 4/5 Biology Course Unit 1

Cell Structure We will now look in more detail at the structure of animal and plant cells. To see more detail or the ultra structure of cells we need to use and electron microscope. An electron microscope is a type of microscope that uses an electron beam to illuminate a specimen and produce a magnified image. An electron microscope (EM) has greater resolving power than a light optical microscope and can reveal the structure of smaller objects because electrons have wavelengths about 100,000 times shorter than visible light photons. They can achieve better than 50 pm resolution[1] and magnifications of up to about 10,000,000x whereas ordinary, non-confocal light microscopes are limited by diffraction to about 200 nm resolution and useful magnifications below 2000x. Electron microscopes are used to investigate the ultrastructure of a wide range of biological and inorganic specimens including microorganisms, cells, large molecules, biopsy samples, metals, and crystals. Industrially, the electron microscope is often used for quality control and failure analysis. Modern electron microscopes produce electron micrographs, using specialised digital cameras or frame grabbers to capture the image. Image from Wikipedia commons National 4/5 Biology Course Unit 1 15

Cell Structure - Organelles
Organelle is the name given to the structures found inside the cell e.g. Nucleus, vacuole, chloroplasts etc. You need to know about 2 more organelles. Mitochondria and Ribosomes National 4/5 Biology Course Unit 1

Mitochondria Mitochondria are the power houses of cells. They convert energy into forms that are usable by the cell. They are found in the cytoplasm and are the sites of cellular respiration which generates fuel for the cell's activities. Mitochondria are found in the cytoplasm of the cell. National 4/5 Biology Course Unit 1

Electron microscope image of a mitochondrion (credit: Tom Deerinck and Jeff Martell/MIT) National 4/5 Biology Course Unit 1

Ribosomes Ribosomes can be found floating free in the cytoplasm or attached to another type of organelle called Rough Endoplasmic Reticulum or R.E.R. for short. (you don’t have to know about R.E.R!) National 4/5 Biology Course Unit 1

Ribosomes are responsible for protein synthesis, i.e. this is where amino acids are assembled into proteins. Electron Microscope image of ribosomes. National 4/5 Biology Course Unit 1

Cell Structure – Organelles
Task 3 – Collect the diagram sheets of the animal cell and the plant cell. Label any structures you recognise. You will need to include:- Cell membrane, nucleus, cell wall, vacuole, chloroplast, cytoplasm, ribosome and mitochondria. National 4/5 Biology Course Unit 1

Animal Cell Diagram Cytoplasm Nucleus Ribosomes Mitochondrion Cell Membrane National 4/5 Biology Course Unit 1

Plant Cell Diagram Ribosomes Mitochondria Cell Membrane Cytoplasm Cell Wall Nucleus Chloroplast Vacuole National 4/5 Biology Course Unit 1

Cell Structure - Organelles
Task 4 – Collect and complete the worksheet :– Cell structures and functions. National 4/5 Biology Course Unit 1

Bacteria and fungi LI: 1. Identify and name the structures found in a bacterial cell. 2. State the function of the structures in a bacterial cell. 3. Identify and name the structures found in a fungal cell. 4. State the function of the structures in a fungal cell. National 4/5 Biology Course Unit 1

Bacterial Cells “For the first half of geological time our ancestors were bacteria. Most creatures still are bacteria, and each one of our trillions of cells is a colony of bacteria.” Richard Dawkins National 4/5 Biology Course Unit 1

Bacteria TThey are the oldest living organisms on earth. They are everywhere. We find them on and in the human body, in the air we breathe, on the surfaces we touch, in the food we eat. Almost 99% of these bacteria are helpful, whereas the remaining are the notorious ones. Some are essential for proper growth of other living beings. They are either free-living or form a symbiotic relationship with animals or plants. National 4/5 Biology Course Unit 1

Structure of Bacteria Bacteria can occur in different shapes. However their basic structure is the same. Task: Collect the bacterial cell diagram handout and the information sheet. Use the information to complete the labels on the diagram and to complete the table. National 4/5 Biology Course Unit 1

Cytoplasm Cell Wall Capsule Plasmid Genetic material Cell Membrane National 4/5 Biology Course Unit 1

Structure Function and importance Capsule Cell Wall Cell Membrane Genetic Material Plasmid Cytoplasm Provides additional protection from the environment It strengthens and supports the cell Controls the movement of substances into and out of the cell Made of DNA and controls the activities of the cell Circular genetic material. Can convey special abilities, e.g. a resistance to certain antibiotics. They can be manipulated by man to produce bacterial cells that produce useful products e.g. Insulin, hormones and enzymes. Most chemical processes take place here controlled by enzymes National 4/5 Biology Course Unit 1

Structure of a fungal cell
Task: Collect the diagram sheet and label any of the structures and organelles you recognise. National 4/5 Biology Course Unit 1

Structure of a fungal cell
Nucleus Cell Wall Cytoplasm Vacuole Cell Membrane National 4/5 Biology Course Unit 1 32

All the cell parts are now familiar. You should be able to compare all the cell types and identify which parts are similar and which are not. While all the cell parts have the same functions as before there is one difference. The fungal cell wall. Just as the bacterial cell wall has a different chemical structure from a plant cell wall, so does the fungal cell wall. The fungal cell wall is made from a chemical called chitin. National 4/5 Biology Course Unit 1

It is important that you know
The cell walls in plant, bacterial and fungal cells is structurally and chemically different. National 4/5 Biology Course Unit 1

Measuring cell size LI: 1. Be able to calculate the length and breadth of cell seen through a microscope. National 4/5 Biology Course Unit 1

Just how tiny are cells? “How big?” This link will show you how tiny cells are. Cells can be seen more clearly using a microscope. National 4/5 Biology Course Unit 1

Magnification Total magnification is worked out by multiplying the eyepiece lens magnification by the objective lens magnification. Eyepiece Lens Objective Lens National 4/5 Biology Course Unit 1

Copy and complete this table
Eyepiece lens magnification Objective lens magnification Total magnification X 10 X 4 X 100 National 4/5 Biology Course Unit 1

Working out the size of a cell
The field of view is the area you can see down the microscope. Field of view = 2 mm Field of view Length = of each cell (mm) Number of cells e.g. 2 ÷ 5 = 0.4 mm So each cell measures 0.4 mm. National 4/5 Biology Course Unit 1

Field of view = 2 mm Collect a version of this diagram. Your teacher will tell you how many cells to draw in the circle. Calculate the length of your cell in millimetres (mm). Swap with other and calculate the length of their cells. National 4/5 Biology Course Unit 1

2. Transport across cell membranes

The cell membrane LI: 1. Describe the composition of the cell membrane 2. Describe how the structure of the membrane relates to its permeability. 3. Define the term “passive transport” National 4/5 Biology Course Unit 1

The Cell Membrane The cell membrane (or plasma membrane) is made up of a bilayer of lipids with protein scattered throughout and is selectively permeable. Proteins can; be attached to the surface be embedded within the bilayer span the whole bilayer form channels in the lipid bilayer National 4/5 Biology Course Unit 1

Small molecules can pass through pores in the membrane made by channel forming proteins and enter or leave the cell. This is why the plasma membrane is selectively permeable. This transport of molecules is passive and requires no energy as it is with the concentration gradient. National 4/5 Biology Course Unit 1

Diffusion LI: 1. Define the term “diffusion” 2. Explain how the process of diffusion occurs across a selectively permeable membrane. National 4/5 Biology Course Unit 1

Diffusion Diffusion is the name given to this movement of the molecules of a substance from a region of high concentration of that substance to a region of low concentration of that substance until the concentration becomes equal. National 4/5 Biology Course Unit 1

Diffusion Activity Cut a 20cm piece of visking tubing and tie a knot in one end. Soak the tubing in water and never let it dry out during the experiment. Fill the visking tubing with 5-10cm3 starch and glucose solution and seal with another knot. Place this in a boiling tube of water completely submerged and leave until the next lesson. National 4/5 Biology Course Unit 1

Take a small sample of the water from around the test tube. Test for starch and sugar 2. Add 4 drops of IODINE Test for starch 1. Put sample on tray 3. If starch is present it goes from brown to black 2. Add 4 drops of BENEDICTSSOLUTION Test for sugar BOILING WATER 1. Put sample in test tube – IN a beaker of BOILING WATER 3. If sugar is present it goes from blue to orange National 4/5 Biology Course Unit 1

Activity Perform Benedict’s test and starch test on the water in the boiling tube from Diffusion in a Model Cell experiment you set up last lesson. Explain your results in terms of diffusion. (LO1 assessment). National 4/5 Biology Course Unit 1

Importance of diffusion to cells
In an animal cell, food (such as glucose), oxygen and carbon dioxide will diffuse like this: National 4/5 Biology Course Unit 1

Glucose Oxygen Carbon dioxide National 4/5 Biology Course Unit 1

Substances which diffuse in or out of cells
Diffuse OUT Oxygen (raw material for respiration) Carbon dioxide (waste from respiration) Carbon dioxide (PLANTS ONLY, raw material for photosynthesis) Oxygen (PLANTS ONLY, made in photosynthesis) Glucose (raw material for respiration) Urea (a cell waste product) Amino acids (raw materials to build the cell) National 4/5 Biology Course Unit 1

Osmosis LI: 1. Define the term “osmosis” 2. Explain how the process of osmosis occurs across cell membranes. 3. Describe the effects of osmosis on animal and plant cells. National 4/5 Biology Course Unit 1

Gummi bears in water Take a gummi bear (Haribo works best) and measure its height and width. Place in a 50 ml beaker of water. Leave for several days. Carefully remove from the water, and measure the height and width. What has happened to the Gummi bear? Why has this happened? National 4/5 Biology Course Unit 1

Osmosis: the diffusion of water
National 4/5 Biology Course Unit 1

Osmosis The diffusion of water through a selectively-permeable membrane from an area of high concentration of water molecules to an area of low concentration of water molecules is called osmosis. National 4/5 Biology Course Unit 1

Effects of Osmosis on Plant Cells
Cells in a dilute solution become turgid Cells in concentrated solutions become flaccid. Cells in the same solution stay the same. Plasmolysed cell – cytoplasm is pulled away from the cell wall. National 4/5 Biology Course Unit 1

Turgid Cells Osmosis makes plant cells swell. Water moves into the plant cell vacuole and pushes against the cell wall. The cell wall stops the cell from bursting. We say that the plant is turgid. This is useful as it gives plant stems support. National 4/5 Biology Course Unit 1

Flaccid Cells If a plant lacks water, it wilts and the cells become flaccid as water has moved out of the cell. If alot of water leaves the cell, the cytoplasm starts to peel away from the cell wall. We say the cell has undergone plasmolysis. National 4/5 Biology Course Unit 1

Osmosis in Animal Cells

Active transport LI: Define the term “active transport” Explain how active transport occurs across cell membranes. National 4/5 Biology Course Unit 1

Active Transport Active transport is the movement of molecules across a cell membrane from a low to a high concentration i.e against a concentration gradient. Active transport works in the opposite direction to the passive transport of diffusion and always requires energy. This energy is released during respiration. National 4/5 Biology Course Unit 1

ENERGY National 4/5 Biology Course Unit 1

3. Producing New Cells

Producing new cells LI: Describe the stages of mitosis. Describe the maintenance of the diploid chromosome complement by mitosis. Explain why mitosis is used by cells. National 4/5 Biology Course Unit 1

Everyone in this room started life as a single cell, a fusion of a sperm and egg cell. What processes must have happened to develop you from that single cell? National 4/5 Biology Course Unit 1

How many new cells do you think you will make in a day?
Cell Division throughout Life National 4/5 Biology Course Unit 1

in 20 minutes so… 23,760,000,000 new cells every day! National 4/5 Biology Course Unit 1

What do these pictures all have in common?

They are all examples of Cell Division in action for growth or repair!

How do Cells Divide? Mitosis – watch this clip on the process of mitosis and answer the following questions: How are new cells produced? What are chromosomes? Where are they found? What kind of cells undergo mitosis? What are the only kind of cells that do not undergo mitosis? National 4/5 Biology Course Unit 1

Put the following stages of mitosis in the correct order:
New nuclear membranes form around the chromosomes, followed by new cell membranes, creating two new identical cells. Chromosomes replicate to form identical chromatids. Spindle fibres then pull the matching chromatids apart, to opposite poles of the cell. The membrane around the nucleus breaks down, and spindle fibres attach to the chromatids and line them up in the centre of the cell - equator. National 4/5 Biology Course Unit 1

Why do chromosomes need to be copied so carefully and put into each new cell? Chromosomes carry GENES, which are stretches of DNA. Each GENE codes for one protein e.g. one gene codes for haemoglobin, the substance in red blood cells that carries oxygen. Other genes will code for other molecules that make up the body. National 4/5 Biology Course Unit 1

Chromosome Complement
The number of chromosomes that a species of animal or plant possesses. Why so you think it is important that each new cell has the same chromosome complement as the parent cell? National 4/5 Biology Course Unit 1

During growth and development of an organism will be able to provide the animal or plant with all the characteristics of its species. Losing any chromosome would mean a loss of genetic information – the information that forms the code allowing the cell to function correctly! National 4/5 Biology Course Unit 1

What goes wrong in Cancer?
Decreased cell death = more cells Ability to invade surrounding tissues 4 5 3 4 4 5 1 2 5 3 4 4 4 1 4 4 5 5 5 5 5 4 4 4 5 4 4 5 5 4 5 5 5 2 4 4 4 5 5 5 4 5 5 5 5 4 4 4 5 4 4 5 5 5 5 Increased cell division = more cells Loss of contact inhibition – the cells no longer stay in one place Ability to move - metastasis Escape from immune surveillance = cells not destroyed National 4/5 Biology Course Unit 1 Loss of DNA Repair

Cancer cells – Research Task
1. Find out the meaning of the following terms… Benign Malignant Metastasis 2. Research a type of cancer and find out the following: What part of the body does this cancer affect? What are the clinical symptoms? How common is this cancer (in the UK)? What is the treatment given for this cancer? What research is being done on this cancer? Is there a charity fundraising to help support people affected by this type of cancer? National 4/5 Biology Course Unit 1

Cell culture LI: Describe how cells are produced using cell-culture techniques. Describe the aseptic techniques that are used when culturing cells. National 4/5 Biology Course Unit 1

Cell culture Growing cells in the laboratory is known as cell culture. To grow cells in the lab you need: A suitable growing medium Availability of oxygen A suitable temperature A suitable pH level National 4/5 Biology Course Unit 1

Cells can be grown in nutrient broth in fermenters or flasks. Or the broth can be mixed with agar to make a solid agar plate. National 4/5 Biology Course Unit 1

To provide ideal growing conditions cultures are grown in incubators. These allow temperature, humidity, pH, carbon dioxide and oxygen levels to be controlled. National 4/5 Biology Course Unit 1

Aseptic techniques In order to work with cell cultures you have to use aseptic techniques in order to prevent contamination. Your teacher will then show you how to streak out bacterial colonies using aseptic techniques. National 4/5 Biology Course Unit 1

Read page 45 of the textbook. Using what you learned streaking out the bacteria, take a page in your jotter and create a “Guide to being aseptic”. National 4/5 Biology Course Unit 1

4. DNA and Protein Production

DNA LI: Describe the structure of DNA. State the names of the four bases that make up the genetic code. National 4/5 Biology Course Unit 1

What is DNA? Watch the following video that introduces DNA and its importance. DNA video This video also covers some different types of protein that could link with the protein and enzymes section. Synopsis of Video Issues of genetics and DNA are constantly cropping up in the news from food production and health, to legal cases and ethics. We hear about DNA in movies like Jurassic Park and X-men, we learn bits and pieces about it from TV shows like Dexter and and CSI, but what exactly is DNA, and how does it work? This animated short film has been made for those wanting a simple introduction (or even a refresher) on how DNA creates a living creature. In this video you will learn a bit about genetic code, DNA transcription and translation, and the importance of proteins in the chemistry of life. Video was written, presented, and animated by Jon Perry Music by Anthony Danzl (check out his website at ) Research and instructional design by Varinia Acosta You can learn more about DNA and Stated Clearly on our website at National 4/5 Biology Course Unit 1 87

DNA, genes and chromosomes
The cell’s nucleus contains chromosomes made from long DNA molecules. DNA DNA molecules are large and complex. They carry the genetic code that determines the characteristics of a living thing. Genes Think back to the last section! National 4/5 Biology Course Unit 1

DNA, genes and chromosomes
The diagram shows the relationship between the cell, its nucleus and the chromosomes in the nucleus that are made up of DNA, and genes. DNA Image adapted from:- National 4/5 Biology Course Unit 1 Collect the handout sheet and stick it into your jotters. 89

From Genes to Proteins? Watch the following video that gives a basic definition of a gene and what genes do. What exactly is a gene? Synopsis of video Published on 26 Nov 2012 You've probably heard about GMOs or Genetically Modified Organisms but what exactly is a gene and what does it mean to modify the genes of a plant or animal? We hear about DNA and genes all the time in the news and in our biology classes but very few of us can actually explain what a gene is? This short film is designed to help. Here we discuss a basic definition of a gene, show what a gene looks like, what it is that genes actually code for, and the basic idea behind Genetically Modified Organisms. The video also briefly mentions one of the ways DNA strongly suggests that all living things are related and share an evolutionary history. Even though the content given here is just a simplified overview of genetics, after watching this video (along with our first video on DNA you should be able to easily follow any news article, basic conversation, or 100 level college course lecture on genetics, even if you've never taken a biology course or studied genetics in the past. Special thanks to Hip Hop Artist Anthony Danzl for the music Content for this video has been modified from two text books: Molecular Biology of the Cell, third edition: Bruce Alberts, Dennis Bray, Julian Lewis, Martin Raff, Keith Roberts, James D. Watson Biology Eighth Edition: Neil Campbell, Jane Reece, Lisa Urry, Michael Cain, Steven Wasserman, Peter Minorsky, Robert Jackson Chimps and humans share 96% of their DNA comes from National Geographic: Fruit flies share about 50% their genes with humans comes from NASA and NCBI (National Center for Biotechnology Information) Hope you liked the video, more are in the works. Stay Curious! National 4/5 Biology Course Unit 1 90

DNA Structure DNA consists of two molecules that are arranged into a ladder-like structure called a Double Helix. A molecule of DNA is made up of millions of tiny subunits called Nucleotides. National 4/5 Biology Course Unit 1

Nucleotide Structure Each nucleotide consists of: Phosphate Group Deoxyribose Sugar Organic Base Copy this diagram into your jotters. National 4/5 Biology Course Unit 1

DNA Structure The phosphate and sugar form the backbone of the DNA molecule, whereas the bases form the “rungs”. Collect the handout and stick it into your jotters. Teacher discussion about strong chemical bonds that hold the nucleotides together and the base pairs being held together by weak hydrogen bonds. Pupils do not need to know this information. National 4/5 Biology Course Unit 1 93

The Genetic Code The genetic code determines the order in which amino acids are joined together to produce a specific protein. The code itself is determined by the order of the organic bases in the DNA molecule. There are 4 different bases. Guanine Cytosine Adenine and Thymine Proteins are covered in the next section 5. Proteins and Enzymes but it maybe useful to discuss the importance of the different types of proteins here. To help remember the way in which the base pairs join together G-CAT. National 4/5 Biology Course Unit 1 94

Each base can only join with one other type of base:- Guanine always pairs with Cytosine Adenine always pairs with Thymine G-C and A-T These are called complementary base pairs. National 4/5 Biology Course Unit 1

Complementary Base Pairs
Image from: National 4/5 Biology Course Unit 1 96

Build your own DNA Molecule
Task 1: Collect the handout sheets DNA origami instructions and template Follow the instructions to complete your own model DNA! Links to this task can be found at - An additional task could be to link all the DNA models produced to form one very long DNA chain for display in the class or elsewhere in the school – the DNA of the biology class! National 4/5 Biology Course Unit 1 97

DNA and proteins LI: Explain the relationship between DNA and proteins. Explain the relationship between the order of bases on DNA and the amino acids in a protein. Describe the role of mRNA in protein production. Name the basic units that proteins are made from and where protein synthesis takes place. National 4/5 Biology Course Unit 1

Protein Structure Proteins are made up of amino acids. The order of the amino acids determines the proteins molecular structure, its shape and its function. The order of the amino acids is determined by the order of the bases in the DNA molecule – the genetic code. National 4/5 Biology Course Unit 1

So how does the genetic code get translated into a protein? National 4/5 Biology Course Unit 1

Watch Again Watch the ‘What is DNA?’ video again. This time try to answer the following questions:- Video How is the genetic code from the DNA molecule copied? What happens to the copy of the genetic code? Where does it go? In which organelle is the copy of the genetic code translated to form proteins? How are the proteins formed? Watch the video from 2.14 minutes in. The video only mentions RNA and doesn’t refer to it as mRNA. National 4/5 Biology Course Unit 1 101

Teacher to use this image to discuss protein synthesis for clarification. Pupils do not need to know about tRNA or detail of how transcription and translation take place. National 4/5 Biology Course Unit 1 102

Translating the genetic code
Task 1: Using the information in the video, the questions and discussion with your teacher write a short paragraph to describe how the genetic code from the DNA is translated into a protein. Or use the following slide and cloze exercise to make a record of how the genetic code is translated. You could use a diagram to help illustrate you description. National 4/5 Biology Course Unit 1 103

The genetic code in the DNA is copied or transcribed by another molecule called Messenger RNA (mRNA). The mRNA carries the code out of the nucleus to the ribosomes in the cytoplasm. The ribosomes then translate the code from the mRNA into the specific protein using amino acids found free in the cytoplasm. Optional slide to be used in conjunction with the CLOZE exercise – Translating the genetic code or/ Use this slide to check pupils work. National 4/5 Biology Course Unit 1 104

mRNA The DNA for the gene being turned into a protein is copied into a mRNA molecule. It is different from DNA, it is: Shorter Single stranded Have URACIL instead of THYMINE. National 4/5 Biology Course Unit 1

How does mRNA become a protein
Every 3 letters in the mRNA tell the ribosome which amino acid to add to the protein. A U G C G A U G G A C G mRNA Alanine Serine Glycine Proline National 4/5 Biology Course Unit 1

Task 3: In groups produce an A4 poster to illustrate protein synthesis. Your poster should contain the following information:- DNA carries the genetic code for producing proteins mRNA copies the code mRNA carries the copy of the code to the ribosomes The ribosomes translate the copy of the code to produce proteins National 4/5 Biology Course Unit 1 107

5. Genetic Engineering

Genetic engineering LI: Describe how genetic information can be transferred from one cell to another. Explain the process of genetic engineering and the stages involved. National 4/5 Biology Course Unit 1

What is genetic engineering? What is it used for? National 4/5 Biology Course Unit 1

Watch the following clip on Genetic Engineering and in pairs answer the following questions: What 3 things are produced by genetically modifying microbes? Name the first organisms to be genetically modified and when this was done. What does insulin normally do? What condition arises from not making insulin? National 4/5 Biology Course Unit 1

GMO Defined… An organism that is generated through genetic engineering is considered to be a genetically modified organism (GMO). The first GMOs were bacteria in 1973; GM mice were generated in Insulin-producing bacteria were commercialized in 1982 and genetically modified food has been sold since 1994. National 4/5 Biology Course Unit 1

The process of Genetic Engineering
The control of all the normal activities of a bacterium depends upon its single chromosome and small rings of genes called plasmids. In genetic engineering pieces of chromosome from a different organism can be inserted into a plasmid. This allows the bacteria to make a new substance. National 4/5 Biology Course Unit 1

Use the following diagram to help you.
Task 1 – Use the cut out sheet and put the stages of genetic engineering in the correct order. Use the following diagram to help you. National 4/5 Biology Course Unit 1

Uses of Genetic Engineering 1
Genetic engineering is used for the production of substances which used to be both expensive and difficult to produce. Examples include: insulin for the control of diabetes antibiotics such as penicillin various vaccines for the control of disease enzymes for laundry detergent National 4/5 Biology Course Unit 1

Uses of Genetic Engineering 2
Genetic engineering is a way of producing organisms which have genotypes best suited for a particular function. In the past man has used selective breeding to achieve this. This was done by choosing only his most suitable animals and plants for breeding. National 4/5 Biology Course Unit 1

Genetic engineering has several advantages over selective breeding. Some are: particular single characteristics can be selected the selection may be quicker a desirable characteristic can be transferred from one species to another National 4/5 Biology Course Unit 1

Genetic Engineering – now and the future?
It is not just bacteria that can be genetically modified, plants and animals can be modified too. It is therefore possible to genetically engineer people! It holds the promise of curing genetic diseases like cystic fibrosis, and increasing the immunity of people to viruses. National 4/5 Biology Course Unit 1

It is speculated that genetic engineering could be used to change physical appearance, metabolism, and even improve mental faculties like memory and intelligence, although for now these uses seem to be of lower priority to researchers and are therefore limited to science fiction. National 4/5 Biology Course Unit 1

Issues? There are dangers involved with genetic engineering since it involves creating completely new strains of bacteria. There is a possibility of creating some which are harmful to animal or plant life. What is your opinion on GM Food (plant and animal), GM organisms for research and GM People? National 4/5 Biology Course Unit 1

Task 2 – Genetically Engineering the Future
Thinking about the possibilities and issues surrounding genetic engineering, I want you to imagine 50 years from now. Technology has moved on and GMO is commonplace in agriculture, medicine and all organisms. Write a letter to your present self, describing this new world. Be honest in this letter, what are the good and bad points about GMO in the future? National 4/5 Biology Course Unit 1

6. Proteins and Enzymes

Protein structure LI: Explain how the variety of protein shapes and functions arises. Describe some of the main functions of proteins. National 4/5 Biology Course Unit 1

Protein structure Proteins are made up of sub-units called amino acids. There are 21 amino acids. The order of amino acids in a protein is dictated by the genetic code. Every protein has different amino acids in different orders. National 4/5 Biology Course Unit 1

The order of the amino acids affects the shape of the protein. Proteins can be fibrous or globular: GLOBULAR – enzymes FIBROUS – keratin (hair) National 4/5 Biology Course Unit 1

Protein functions Read pages 58 – 60. Make a mind-map showing the 5 main functions of proteins. National 4/5 Biology Course Unit 1

Enzymes LI: State what enzymes are and where they can be found. Describe the main function of an enzyme. Define the terms “active site” and “substrate”. Explain the relationship between the active site of an enzyme and its substrate. National 4/5 Biology Course Unit 1

Catalysts A catalyst speeds up a chemical reaction, but is unchanged in the process and can be used over and over again. In living things, catalysts are known as enzymes. National 4/5 Biology Course Unit 1

If cells did not have enzymes in their cytoplasm, then the chemical reactions which happen in our cells would happen so slowly that life would be impossible! National 4/5 Biology Course Unit 1

An example of an enzyme: CATALASE
Hydrogen peroxide (H2O2) is a liquid similar to water (H2O), but with one extra oxygen. Over a long period of time hydrogen peroxide naturally breaks down into water and oxygen. National 4/5 Biology Course Unit 1

The word equation for this reaction is: Hydrogen peroxide water + oxygen This process can be sped up using an enzyme. National 4/5 Biology Course Unit 1

Into each test tube – measure out 5 ml of Hydrogen peroxide AND 5 drops of detergent.
CAUTION!! Hydrogen peroxide is a dangerous chemical. Safety goggles must be worn!! Add nothing Potato Carrot Liver Leave for 10 minutes. Measure the height of the foam bubbles. National 4/5 Biology Course Unit 1

Test tube contents Height of foam (mm) Nothing – “CONTROL” Potato Carrot Liver National 4/5 Biology Course Unit 1

Conclusion Only the plant and animal tissues speed up the breakdown of hydrogen peroxide. This is because the cells contain catalase. Catalase is an enzyme found in living cells. National 4/5 Biology Course Unit 1

Catalase Hydrogen peroxide water + oxygen The tissue which contained the most catalase was ______________. National 4/5 Biology Course Unit 1

Breakdown and Synthesis
Catalase is an enzyme involved in chemical breakdown. “Breakdown” means chopping up larger molecules into smaller molecules. National 4/5 Biology Course Unit 1

Other enzymes do the opposite – the build large molecules from smaller molecules. This is called synthesis. National 4/5 Biology Course Unit 1

An example of a synthesis enzyme: Phosphorylase
Glucose-1-phosphate is a chemical made by plants during photosynthesis. It is stored in plant cells be converting it into a large molecule called starch. National 4/5 Biology Course Unit 1

Phosphorylase Phosphorylase Glucose-1-phosphate Starch National 4/5 Biology Course Unit 1

Substrates and products
The substrate is the substance the enzyme works on. The product is the substance the enzyme makes. Enzyme Substrate Product National 4/5 Biology Course Unit 1

Enzyme Substrate Product Catalase Phosphorylase Amylase Pepsin Lipase National 4/5 Biology Course Unit 1

How enzymes work Enzymes are made of protein. This protein has a special shape which is unique to each enzyme. Enzyme Active site National 4/5 Biology Course Unit 1

Substrate Enzyme The active site is the correct shape to fit the substrate. Substrate Turned into the products Enzyme National 4/5 Biology Course Unit 1

Substrate Enzyme Other substrates are the wrong shape to fit in the active site of the enzyme. Therefore the enzyme will only work with one substrate. This is described as being SPECIFIC. National 4/5 Biology Course Unit 1

“Specific” When talking about enzymes, SPECIFIC means that the ENZYME WILL ONLY WORK WITH ONE SUBSTRATE. National 4/5 Biology Course Unit 1

One enzyme = one substrate
5 ml Starch 5 ml Starch 5 ml Starch 5 ml Starch 3 ml Water 3 ml Amylase 3 ml Pepsin 3 ml Lipase Put in waterbath for 10 minutes. Test all 4 test-tubes with Benedict’s Solution National 4/5 Biology Course Unit 1

Results Sugar present? Starch + water Starch + amylase Starch + Pepsin Starch + Lipase National 4/5 Biology Course Unit 1

Conclusion The test-tube containing Starch and Amylase had the most sugar. This shows that only Amylase can convert starch to sugar. Amylase is said to be SPECIFIC to starch. National 4/5 Biology Course Unit 1

Factors affecting enzyme activity
LI: Explain the meaning of the term “optimum” as applied to enzymes. Give factors that affect enzymes and their proteins, and describe their effect. Explain the meaning of the term “denatured” and why it happens to enzymes. National 4/5 Biology Course Unit 1

Effect of temperature on enzymes

5 ml Starch ml Starch ml Starch 3 ml Cold Amylase 3 ml Amylase 3 ml 80oC Amylase Iced water oC oC Put in waterbath for 10 minutes. Test all 3 test-tubes with Benedict’s Solution National 4/5 Biology Course Unit 1

Temperature Was sugar present? 0 oC 37 oC 80 oC National 4/5 Biology Course Unit 1

All enzymes have a temperature at which the work fastest. This is called the optimum temperature. In humans the optimum temperature for all enzymes is 37oC. National 4/5 Biology Course Unit 1

Enzymes work slowly at cold temperatures. National 4/5 Biology Course Unit 1

At very high temperatures enzymes become changed and do not work. This is called being denatured. Once an enzyme is denatured it will never work again. National 4/5 Biology Course Unit 1

The effect of pH on enzymes
Into all 5 test tubes put 5ml Hydrogen Peroxide and 5 drops of soap 3ml pH1 buffer 3ml pH4 buffer ml pH7 buffer 3ml pH9 buffer 3ml pH 14 buffer LAST: Add 1 cm cylinder of potato to each test tube. Measure height of foam after 10 minutes. National 4/5 Biology Course Unit 1

Results pH Height of foam (mm) 1 4 7 9 14 National 4/5 Biology Course Unit 1

Conclusion The optimum pH for the catalase enzyme is pH _______. All enzymes have a different optimum pH depending on where they are found in the body. National 4/5 Biology Course Unit 1

Yoghurt and cheese making Biological detergents
Uses of enzymes Yoghurt and cheese making Biological detergents

Yoghurt and cheese Yoghurt and cheese making depend on the activities of enzymes in bacteria. Bacteria used lactose sugar in milk as a source of energy. National 4/5 Biology Course Unit 1

They make the waste product called lactic acid which makes the milk increasingly acidic and sour tasting. Lactose energy + lactic acid National 4/5 Biology Course Unit 1

This is another example of fermentation. National 4/5 Biology Course Unit 1

Yoghurt making Milk is heated to kill microbes Special yoghurt bacteria are added The lactose in the milk is fermented by the bacteria. The milk becomes acidic and so it: Thickens Tastes sour National 4/5 Biology Course Unit 1

2. Cheese making The process is similar to yoghurt making, but after the fermentation, rennet is added which curdles the milk. The solid curds are separated from the liquid whey. The curds are then pressed into hard cheese. National 4/5 Biology Course Unit 1

Task 3 – Note Taking The following slides will tell you about biological detergents; how they are made, why they are useful and their environmental impact. Your task is to take notes from the slides – this could be mind mapping key words and concepts under the headings above or a table of information or bullet point. Decide quickly which method you find most useful when revising and try it this way. National 4/5 Biology Course Unit 1

How Biological Detergents are produced:
Biological detergents contain enzymes such as protease, amylase and lipase to digest proteins, starch and fats respectively. Enzymes can be produced using bacteria that have been genetically engineered to make these enzymes. They are grown in industrial fermenters in vast quantities. This equipment ensures that the bacteria receive food and oxygen so that they grow well. The bacteria will produce the enzymes and pass them out into the culture liquid. The bacteria and the filtered off and the enzymes extracted from the liquid. The enzymes are purified and added to washing powder. National 4/5 Biology Course Unit 1

Value and Use of Product:
Advantages of using biological detergents include reducing fuel costs as clothes can be washed at lower temperatures reducing the electricity consumption; Less damage to delicate fabrics such as acrylic and wool whilst still cleaning effectively and the ability to remove difficult stains such as grass and blood. These will be completely removed by biological washing powder but not by non-biological even at high temperatures. National 4/5 Biology Course Unit 1

Environmental Impact 1:
Reduced Fuel Consumption - using Biological Detergents has a positive impact on our environment as it reduces CO2 and SO2 production from burning fossil fuels in Power Stations to generate electricity. National 4/5 Biology Course Unit 1

Environmental Impact 2:
Detergents are rich in chemicals called phosphates. This chemical passes from waste water from people’s homes to sewage works. Unfortunately it is hard to remove during processing and can end up in local rivers where they cause algal bloom. This single celled plant can overwhelm the balance of the ecosystem and when it dies can cause bacterial numbers to increase. The bacteria use up oxygen in the water which leads to the death of other organisms. National 4/5 Biology Course Unit 1

Task 3 – Note Taking Your task was to take notes from the slides – it would be useful to check your notes with a peer. Have you covered similar key areas? If you are not sure, the check with your teacher! National 4/5 Biology Course Unit 1

7. Respiration

Cellular respiration LI: Explain what is meant by the term “respiration”. Describe the build up and break down of ATP in cells. Name the cellular uses of ATP. Give the summary word equation for aerobic respiration. National 4/5 Biology Course Unit 1

Why do cells need energy? National 4/5 Biology Course Unit 1

Respiration Why do cells need energy? Living cells need energy to carry out a variety of cell functions. energy in living cells cell growth muscular contraction cell division nerve impulses building up large molecules chemical reactions National 4/5 Biology Course Unit 1

energy from food National 4/5 Biology Course Unit 1

The three main food groups are _____, ____________, and __________. _____ contains the most energy. National 4/5 Biology Course Unit 1

Aerobic Respiration Energy in a cell is produced by a chemical reaction called aerobic respiration. carbon dioxide glucose + oxygen water + Activity – blow into lime water, yeast and balloons. energy released National 4/5 Biology Course Unit 1

ATP The energy produced during aerobic respiration is stored in a molecule called ATP (Adenosine triphosphate). Every molecule of glucose that is “burned” in the cell produces 38 ATP molecules. National 4/5 Biology Course Unit 1

ATP structure ATP is made up of one Adenosine and three phosphates 3 PHOSPHATE GROUPS ADENOSINE High Energy Bond P National 4/5 Biology Course Unit 1

ATP is made by joining ADP (Adenosine diphosphate) and phosphate. ADP  Pi ATP National 4/5 Biology Course Unit 1

As a molecule to transfer energy in cells Glucose + Oxygen Carbon Dioxide Water Energy ATP ADP Pi e.g. Amino Acids Protein molecule RESPIRATION ENERGY TRANSFER WORK National 4/5 Biology Course Unit 1

Aerobic respiration LI: Describe the stages of aerobic respiration with reference to the number of ATP molecules produced. State the location of aerobic respiration in cells. National 4/5 Biology Course Unit 1

Glycolysis Respiration should be seen as a series of enzyme controlled reactions in which 6-carbon glucose is oxidised (broken down) to form carbon dioxide this is accompanied by the synthesis of ATP from adenosine diphosphate (ADP) and inorganic phosphate (Pi). National 4/5 Biology Course Unit 1

Glucose (6C) 2ADP + 2Pi 2ATP Pyruvic Acid (2x3C) National 4/5 Biology Course Unit 1

The first stage of respiration is called Glycolysis. This process takes place within the cytoplasm. does not require oxygen involves the step by step breakdown of a 6-carbon sugar such as glucose to form two 3-carbon pyruvic acid units Glycolysis results in a production of 2ATP. National 4/5 Biology Course Unit 1

What happens next? If there is oxygen available ( the normal situation), then the pyruvic acid produced by glycolysis diffuses into an organelle called mitochondrion for further breakdown if oxygen becomes available. National 4/5 Biology Course Unit 1

Structure of a Mitochondrion Outer Membrane Inner Membrane Cristae Matrix Fluid National 4/5 Biology Course Unit 1

Pyruvic acid from glycolysis diffuses into central matrix fluid Pyruvic acid is broken down further in the presence of oxygen by a cycle of reactions called the Kreb’s cycle releasing most of the 38 ATP produced during respiration National 4/5 Biology Course Unit 1

Anaerobic respiration
LI: State when anaerobic respiration occurs. Describe what happens in anaerobic respiration in animal cell. Describe what happens in anaerobic respiration (fermentation) in yeast/plant cells. National 4/5 Biology Course Unit 1

Anaerobic respiration
If there is no Oxygen- Anaerobic Respiration occurs. Anaerobic respiration occurs in human after heavy exercise. National 4/5 Biology Course Unit 1

Pyruvic acid is converted to either (i) Lactic Acid (in animal and bacterial cells) (ii) Ethanol and carbon dioxide (in plant and fungal cells) No further ATP is made – so only the net 2 ATPs are produced. In animal cells the Lactic Acid is converted back to Pyruvic Acid when oxygen becomes available. National 4/5 Biology Course Unit 1

Complete this summary table
Aerobic respiration Anaerobic respiration Humans Yeast/Plant Site in the cell Number of ATP Final products National 4/5 Biology Course Unit 1

Complete this summary table
Aerobic respiration Anaerobic respiration Humans Yeast/Plant Site in the cell Cytoplasm & Mitochondria Cytoplasm Number of ATP 38 2 Final products Carbon dioxide & water Lactic acid Ethanol & Carbon dioxide National 4/5 Biology Course Unit 1

8. Photosynthesis

The importance of plants
LI: Explain why plants are important. Give examples of plants that are useful to man, and explain what they are used for. National 4/5 Biology Course Unit 1

Photosynthesis Why are plants important? What is photosynthesis? What do plants need for photosynthesis? National 4/5 Biology Course Unit 1

The importance of plants Create a spider diagram with uses/importance of plants. National 4/5 Biology Course Unit 1

Raw materials National 4/5 Biology Course Unit 1

Food National 4/5 Biology Course Unit 1

Medicines National 4/5 Biology Course Unit 1

Photosynthesis Importance of plants FOOD RAW MATERIALS MEDICINES Wheat – for bread Wood – for building Poppy – pain killers Grapes – for wine Cotton – for clothes Foxglove – heart medicine Sugar cane – for sugar Flowers – for perfumes Mint – menthol for cough sweets National 4/5 Biology Course Unit 1

Photosynthesis LI: Give the summary word equation for photosynthesis. Describe what happens during the light reaction. Describe what happens during carbon fixation. State the possible uses of the sugar made in photosynthesis. National 4/5 Biology Course Unit 1

Photosynthesis Green plants make their own food using light energy Green plants convert light energy to chemical energy (food) using a green pigment in the leaves called chlorophyll. National 4/5 Biology Course Unit 1

Carbon Dioxide taken up from air Glucose used for energy or stored as starch Light energy - from sun Oxygen given off as waste Water - from soil National 4/5 Biology Course Unit 1

This can be summarised by the following equation Light energy Carbon dioxide Water Glucose Oxygen Chlorophyll Energy source and pigment which traps it Products Glucose is used for energy, stored as starch or built up into cellulose Oxygen is waste gas Raw Materials National 4/5 Biology Course Unit 1

Chloroplast structure

Stages of Photosynthesis biochemistry
There are two stages of photosynthesis. The equation you have just learned is actually more complex and occurs at two separate stages. National 4/5 Biology Course Unit 1

Stage 1 The first stage is called PHOTOLYSIS. This stage involves using energy from the sunlight to split water molecules into hydrogen and oxygen. National 4/5 Biology Course Unit 1

WATER Oxygen Hydrogen ATP ENERGY Released to the air as oxygen gas Passed on to second stage Passed on to second stage National 4/5 Biology Course Unit 1

Light energy Chlorophyll ADP + Pi Water Chemical energy ATP Hydrogen Oxygen Passed on to second stage Passed on to second stage Released to the air as oxygen gas National 4/5 Biology Course Unit 1

Stage 2 The second stage is known as the Carbon Fixation stage Here the energy and hydrogen from stage one are used along with the carbon dioxide. It is at this stage where glucose molecules are produced. National 4/5 Biology Course Unit 1

From the first stage From the first stage ATP ADP + Pi Hydrogen Glucose Carbon dioxide Enzyme controlled reactions From the air National 4/5 Biology Course Unit 1

This stage is energy consuming so that is where the ATP comes in. This stage is also controlled by enzymes. Carbon dioxide and hydrogen join to give us glucose National 4/5 Biology Course Unit 1

What happens to the glucose?
Glucose which are used for energy (respiration) Storage carbohydrates such as starch - these can be broken down to simple sugars if needed Structural carbohydrates such as cellulose - these are used to build the cell wall National 4/5 Biology Course Unit 1

Limiting factors LI: Describe the limiting factors of photosynthesis. Explain the impact of limiting factors on photosynthesis and growth. National 4/5 Biology Course Unit 1

Limiting factors Three possible factors can limit the rate of photosynthesis in a plant when they are in short supply :- Light intensity – this limits the energy available. Carbon dioxide concentration – this is an essential raw material Temperature – this limits the rate at which the enzymes controlling photosynthesis work. National 4/5 Biology Course Unit 1

Effect of light on the rate of photosynthesis We can use the rate of production of oxygen bubbles by pond weed to measure the rate of photosynthesis Diagram “bubbler” National 4/5 Biology Course Unit 1

Experiment – effect of light on rate of photosynthesis – can use cabomba/elodea and measure oxygen produced or immobilised algae with bicarbonate indicator. Pupils to write up experiment in full. National 4/5 Biology Course Unit 1

A large water trough or sheet of glass stops the heat from the lamp from affecting the experiment. Lamp moved away -> less oxygen bubbles produced The amount of light therefore limits the rate of photosynthesis. It is called a limiting factor. National 4/5 Biology Course Unit 1

Point X Optimum Increasing rate of photosynthesis Increasing light intensity Part B Further increases in light causes no further increase in the rate of photosynthesis since the rate is limited by a shortage of some other factor e.g. carbon dioxide or temperature Part A As light intensity increases the rate of photosynthesis increases. National 4/5 Biology Course Unit 1

Point X Optimum Increasing rate of photosynthesis Carbon Dioxide Concentration Part B Further increases in CO2 conc. causes no further increase in the rate of photosynthesis since the rate is limited by a shortage of some other factor e.g. light or temperature Part A As CO2 conc. increases the rate of photosynthesis increases. National 4/5 Biology Course Unit 1

Increasing rate of photosynthesis 0.2% CO2 Increasing light intensity light intensity is limiting factor CO2 is limiting factor National 4/5 Biology Course Unit 1

Point X Optimum Increasing rate of photosynthesis Increasing temperature Part A As temperature increases the rate of photosynthesis increases. Part B Further increases in temperature results in a drop in the rate due to the denaturing of the enzymes that carry out photosynthesis National 4/5 Biology Course Unit 1

Photosynthesis and horticulture National 4/5 Biology Course Unit 1

Use of lights in horticulture. National 4/5 Biology Course Unit 1

Addition of CO2. National 4/5 Biology Course Unit 1

Photosynthesis and horticulture Horticulture is the cultivation of plants in gardens and greenhouses. The use of a greenhouse helps remove limiting factors: National 4/5 Biology Course Unit 1

(a) Lighting and heat By increasing the light, the rate of photosynthesis increases and leads to an increase in the growth rate of the crop: crop is ready to be picked earlier. increased crop yield. National 4/5 Biology Course Unit 1

(b) Carbon dioxide enrichment Increased carbon dioxide in the atmosphere increases the yield (size) of crops. This happens because the rate of photosynthesis is increased. National 4/5 Biology Course Unit 1

Unit One: Cell Biology.

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Unit One: Cell Biology.

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Presentation on theme: "Unit One: Cell Biology."— Presentation transcript:

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