1. Cell biology Revision

2. KEY WORDS: Gland cells Nucleus Algal cell Cellulose Chloroplast ASSESSMENT: Animal & Plant Cells B2 REVISION – CHAPTER 1 – Cells F StructurePurposePlant/Animal/ Bacteria/all Controls the cells activities Cytoplasm Both Mitochondria RibosomesProtein synthesis takes place Plant Contain chlorophyll, absorb light energy to make food Vacuole Eukaryotic and prokaryotic cells Where is the genetic material in a bacteria cell? Where is the genetic material in a plant cell? Where is the genetic material in an animal cell? What type of cell is shown to the right? What is a prokaryotic cell? What is a eukaryotic cell? Specialised Cells Cells are specialised to carry out a specific function. The structure gives a clue to its function. If a cell has many chloroplasts what would its job be? Where would it be found? If a cell has many mitochondria it is making a lot of energy, which type of cell might it be? How is a root hair cell adapted to absorb water and minerals? How is a sperm cell adapted to swim to the egg?

3. KEY WORDS: Gland cells Nucleus Algal cell Cellulose Chloroplast ASSESSMENT: Animal & Plant Cells B2 REVISION – CHAPTER 1 – Cells H StructurePurposePlant/Animal/ Bacteria/all Controls the cells activities Cytoplasm Both Mitochondria RibosomesProtein synthesis takes place Plant Contain chlorophyll, absorb light energy to make food Vacuole Eukaryotic and prokaryotic cells Where is the genetic material in a bacteria cell? Where is the genetic material in a plant and animal cell? Describe the structure of a bacteria cell (pictured right) Specialised Cells If a cell has many chloroplasts what would its job be? Where would it be found? If a cell has many mitochondria it is making a lot of energy, which type of cell might it be? Say how each are specialised to carry out their function functionA daptations to carry out function 1.sperm cells 2.nerve cells 3.muscle cells 4.root hair cells 5.xylem 6.phloem

4. Exam Questions Questions 1.Why did you flame the loop? 2. Why did you allow the loop to cool? 3. Why is the Petri dish only opened a little? 4. Why do we incubate the bacteria at 25 C? 5. Why do we seal the Petri dish before incubation? 6. What do you call a bacteria that causes disease ? Practical: Growing Bacteria Growing micro-organisms Method Uncontaminated cultures of microorganisms are required for investigating the action of disinfectants and antibiotics. To prepare an uncontaminated culture: Petri dishes and agar must be ________ before use to kill unwanted microorganisms inoculating loops used to transfer microorganisms to the media must be sterilised by passing them through a _________ the lid of the Petri dish should be secured with adhesive tape to prevent __________________ from the air contaminating the culture, and stored _________ _________to stop condensation drops falling onto the agar surface. Missing words: flame, sterilised, microorganisms, upside down Disinfectant = Antibiotic =

5. Chromosomes Learning Outcomes RAG Know that chromosomes are found in the nucleus and carry genes. Know that genes control characteristics of the body. Keywords Cell Nucleus Chromosome DNA characteristics Gene Inherited Gametes Use the key words to fill in the spaces… Information that results in plants and animals having similar characteristics to their parents is carried by ________________, which are passed on in the __________________________ from which the offspring develop. Different _______________ control the development of different _______________________ of an organism. Questions Where in the cell is the genetic information found? What are the X shaped structures in the nucleus? What molecule are chromosomes made of? What do chromosomes carry that control characteristics of the body? Sexual reproduction Male and female ________________ join. The mixture of genetic information from two parents means that offspring are genetically different from their parents.

6. KEY WORDS: Meiosis Ova DNA fingerprint ASSESSMENT: Cell division & Growth Mitosis and the cell cycle H What cell division results in two identical cells being produced from an original cell? What are unspecialised cells called? In body cells, what are found in pairs? Cell division in sexual reproduction By which process are gametes(sex cells) produced? What are the gametes in plants called? What are the gametes in animals called? What is the difference between gametes and body cells? Stem Cells What is so special about stem cells? How could stem cells be used to cure some disorders? More on Mitosis…. Cells divide in a series of stages called the cell ________. One of these stages is __________ where the DNA, which has already been copied, divides. During the cell cycle the ______________ material is doubled and then divided into two ______________ cells. Before a cell can divide it needs to ________ and increase the number of sub-cellular structures such as ribosomes and ____________. The DNA replicates to form two copies of each chromosome. One set of ______________ is pulled to each end of the cell and the nucleus divides. Finally the cytoplasm and cell membranes divide to form two identical cells. Cell division by mitosis is important in the growth, __________, replacement of worn out ________ and _____________ Missing words reproduction, identical, mitosis, genetic, repair, cycle, grow, chromosomes, cells, asexual, mitochondria,

7. KEY WORDS: Meiosis Ova DNA fingerprint ASSESSMENT: Cell division & Growth Mitosis and the cell cycle H What cell division results in two identical cells being produced from an original cell? What are unspecialised cells called? In body cells, what are found in pairs? Cell division in sexual reproduction By which process are gametes(sex cells) produced? What are the gametes in plants called? What are the gametes in animals called? What is the difference between gametes and body cells? Stem Cells A stem cell is an _______________ cell of an organism which is capable of giving rise to ______ other cells type. Stem cells from human ________ and adult ______ marrow can be cloned and made to differentiate into many different types of human cells. Scientific research is trying to find ways that stem cells can be used to cure many _____________. Missing words undifferentiated illnesses bone any embryos More on Mitosis…. Cells divide in a series of stages called the cell ________. One of these stages is __________ where the DNA, which has already been copied, divides. During the cell cycle the ______________ material is doubled and then divided into two ______________ cells. Before a cell can divide it needs to ________ and increase the number of sub-cellular structures such as ribosomes and ____________. The DNA replicates to form two copies of each chromosome. One set of ______________ is pulled to each end of the cell and the nucleus divides. Finally the cytoplasm and cell membranes divide to form two identical cells. Cell division by mitosis is important in the growth, __________, replacement of worn out ________ and _____________ Missing words reproduction, identical, mitosis, genetic, repair, cycle, grow, chromosomes, cells, asexual, mitochondria,

8. Plant Cloning There are two methods of plant cloning… Use the space provided to describe how each method works. CuttingsTissue culture ___________________________________________________ ____________________________________________________ __________________________ Stem Cells F and H Keywords Sexual reproduction Asexual reproduction Gametes Cuttings Tissue culture Embryo transplant Adult cell cloning Clone Asexual reproduction Tick the statements that are true  Only one parent is needed  Male and female gametes join  No joining of gametes  Offspring are genetically identical  Offspring are clones of their parents  Offspring are genetically different to their parents Animal Cloning Embryo transplants An embryo is split up into several groups of cells and each group of cells is put into a host mother. Questions: Is cow A genetically identical to cow B? Is cow B genetically identical to cow C? Adult cell cloning Questions: How do they get the egg cell to begin to divide into an embryo? The lamb is genetically identical to which sheep, A, B or C? Explain your answer. A BC Stem cells from meristems in plants can be used to produce clones of plants quickly and economically. Rare species can be cloned to protect from extinction. Large numbers of identical crop plants with special features such as disease resistance. In therapeutic cloning an embryo is produced with the same genes as the patient. Stem cells from the embryo are not rejected by the patient’s body so they may be used for medical treatment.

9. ______________ = material placed under a microscope. ______________ = the appearance of material when viewed under the microscope. The __________________ of an object is how many times bigger the image is when compared to the object. An electron microscope has much higher ______________ and resolving __________ than a light microscope. This means that it can be used to study cells in much _____________ detail. This has enabled biologists to see and understand many more sub-cellular structures. Missing words Image, magnification, finer, object, power, magnification Top tip – to help you remember the equation I AM Match the unit with the correct symbol Use the triangle to complete the following equations: Magnification = Real/actual size = Image size = Micrometer nm Millimeter cm Centimeter mm Nanometer µm Place the following units in order of size, starting with the largest first Microscopy Resolution The resolution or resolving power of a microscope is the minimum distance apart two objects can be in order for them to appear as separate items. The greater the resolution the greater the clarity. The image produced is clearer and more precise. Light microscope Electron microscope Can see images in colour Small field of view Slides are cheap and easy to prepare Can only view dead objects Magnification is 600x bigger than the object.

10. Surrounding solution Where are there more water molecules? Does water enter or leave the cell. OSMOSIS - definition Osmosis is the movement of ___________ molecules from a _____________ solution to a ______________ solution through a __________ permeable membrane. Pure waterWeak salt concentration Strong salt concentration water concentrated Dilue Partially

11. 1. Complete the equation for respiration Glucose + ___________ water + ___________ _________ + energy What gas is needed for respiration? Where does respiration occur? What is the useful product of respiration? What is the waste product of respiration? How do these gases enter and leave the cell? Diffusion and definitions.. 2. Substances may move into and out of cells across the cell membranes via diffusion. Diffusion is the ____________ of the particles of any substance in ______________, or particles of a gas, resulting in a net movement from an area of ___________ concentration to an area of _____________ concentration ( __________ a concentration gradient). Some of the substances transported in and out of cells by diffusion are _____________ and ____________ ________in gas exchange, and of the waste product _______ from cells into the blood plasma for excretion in the kidney. 3 Factors which affect the rate of diffusion are: 1. 2. 3. Missing words Oxygen, solution, spreading, lower, carbon dioxide, higher, down, urea 4. In multicellular organisms the smaller surface area to volume ratio means surfaces and organ systems are specialised for exchanging materials. This is to allow sufficient molecules to be transported into and out of cells for the organism’s needs. The effectiveness of an exchange surface is increased by 4 things: 1. 2. 3. 4. 3. Surface area to volume ratios.. Single cells have a _________ surface area to volume ratio. This means their surface is large enough to be able to exchange essential substances. Multicellular organisms have a ___________ surface area to volume ratio. This means their surface is not large enough to be able to exchange essential substances. They overcome tis by having organs specialised for exchange. E.g. humans have ________ and the ___________ ______________.

12. Fish use gills for gas exchange. Gills allow oxygen to enter the blood and carbon dioxide to leave. 1.Gills have numerous folds and fine gill filaments that give them a very large surface area. 2.The folds are kept supported and moist by the water that is continually pumped through the mouth and over the gills, so water is constantly refreshed 3.The walls are thin. 4.The gills have a very good blood supply 5.The oxygenated blood is pumped away to maintain a concentration gradient.. Humans have lungs for gaseous exchange Lungs allow oxygen to enter the blood and carbon dioxide to leave. Lungs have numerous alveoli. Alveoli 1.Are very thin – only one cell thick. 2.Have a very good blood supply 3.Are numerous and so create a very large surface area 4.Are ventilated so a concentration gradient is maintained. Humans have the small intestine to absorb small soluble food (such as glucose, amino acids, fatty acids and glycerol) The small intestine has villi…. 1.The villi INCREASE THE OVERALL SURFACE AREA of the small intestine, thus increasing the volume of substances which can be absorbed by diffusion. 2.The villi have a very GOOD BLOOD SUPPLY as each contains a capillary, which leads to the main blood supply, so when substances diffuse, they can go straight to the bloodstream. 3.Villi have very thin walls to allow faster diffusion. 4.Villi are covered in cells that have thousands and thousands of MICROVILLI. These are exactly the same as the villi, except a lot smaller. They further increase the surface area. Plants have leaves for gaseous exchange. This is so oxygen and carbon dioxide can be exchanged for photosynthesis and respiration. During the day photosynthesis needs carbon dioxide to enter the leaves and oxygen to leave. Leaves 1.Are flattened to increase the surface area so more gases can enter and leave (and more sunlight can be absorbed. 2.Are thin so there is a shorter distance for the gases to diffuse in and out. 3.Have numerous stomata. These are holes mainly on the underside of the leaves. They can open (usually in daylight) to allow gases to enter and leave. Examples of specialised exchange surfaces

13. Create a revision table using the previous slide.. Organism Exchange surface Substances that are exchanged How the surface is adapted for exchange

14. Active transport moves substances from a more ___________ solution to a more ______________ solution (against a concentration gradient). This requires _____________ from ___________. Active transport allows ____________ ions to be absorbed into plant root hairs from very dilute solutions in the soil. Plants require ions for healthy growth. It also allows ___________ molecules to be absorbed from ____________ concentrations in the gut into the blood which has a __________ sugar concentration. Sugar molecules are used for cell respiration. Missing words: lower, respiration, dilute, mineral, energy, concentrated, sugar higher. Active Transport Give the definition of active transport: How is it different to diffusion: Describe the how glucose is absorbed in the gut, place the sentencess in the correct order Describe active transport in the root hair cell: How is the root hair cell adapted for active transport? Describe the effects of osmosis in animal cells: Describe the effects of osmosis in plant cells: Which type of solution would an animal cell burst in? Why wouldn’t a plant cell burst if also placed in this solution? The molecules are then released into the cell This increases the concentration inside the cell A carrier protein is used to transport molecules across the cell membrane The concentration of glucose is higher inside the cell than outside Molecules need to be taken into the cell against the concentration gradient Active transport occurs when glucose is being moved from a low concentration to a high concentration Energy is required to make the carrier protein work. This energy comes from respiration What would happen if root hair cells absorbed mineral ions by diffusion? What would happen if intestinal cells absorbed glucose by diffusion?

15. Active transportOsmosisDiffusion Does it require energy?NoYesNo Does it require a membrane?yes No An example… Carbon dioxide diffuses into a leaf through stomata for photosynthesis Oxygen diffuses from the alveoli to the blood. Absorption of glucose in the small intestine and mineral ions by root hair cells Absorption of water by root hair cells Reabsorption of water in the kidneys Does it go down a concentration gradient? Substances move along a concentration gradient Substances move against the concentration gradient Water moves along its concentration gradient Comparing the 3 modes of transport – rearrange the mixed up table below