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LO: To describe the appearance and function of the main organelles found within cells Starter Complete worksheet ‘Well - what do you know?’

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Presentation on theme: "LO: To describe the appearance and function of the main organelles found within cells Starter Complete worksheet ‘Well - what do you know?’"— Presentation transcript:

1 LO: To describe the appearance and function of the main organelles found within cells Starter Complete worksheet ‘Well - what do you know?’

2 BATS Describe outline of course and expectations of teachers Name organelles in eukaryotic and prokaryotic cells Identify similarities and differences between eukaryotic and prokaryotic cells Describe the functions of the organelles in eukaryotic and prokaryotic cells

3 1. Holiday pack - collect in 2. Handbook - go through key points 3. Expectations 4. Independent study 5. Revision Guides 6. Science Blog - Mrs Skuse’s AS Keynotes Introduction to course

4 You will discover that things are a lot more complicated and detailed than you thought at GCSE THISbecomesTHIS!

5 You Tube clips to watch - the inner life of a cell ( 3 mins) - Exploring the living cell - (3 mins) - Exploring the living cell - (3 mins) hhttp://www.youtube.com/watch?v=Ao9cVhwPg84&feature=related - voyage inside the cell (15 mins)(15 mins) - - good lecture about the cell (14 mins)

6 There are 2 main types of cells - (NOT animal and plant as you learnt at GCSE) Prokaryotic - these are the oldest types of cells and mainly consist of bacteria - they do NOT have any membrane- bound organelles Eukaryotic - these evolved more recently and consist of all plant and animal cells - they contain membrane bound organelles Prokaryotic and Eukaryotic

7 Copyright © Dean Madden, 2010 The bacterium Bacterial chromosome Plasmids Ribosomes Cell wall Cell membranes Cytoplasm

8 Today we are going to focus on Eukaryotic cells Cells are very small and we need microscopes to study them To see the structures within a cell we need to use a special kind of microscope called and ‘electron microscope’ - we will learn more about this next week The detail within a cell is called its ‘ultrastructure’

9 Structure of an epithelial cell An epithelial cell is a eukaryotic cell Epithelium is one of the four basic types of animal tissue, along with connective tissue, muscle tissue and nervous tissue. Epithelial tissues line the cavities and surfaces of structures throughout the body, and also form many glands.animal, alonissue, muscle tissue. Epithelie cavities and and als

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11 Put the following in order of size starting with the smallest organ, cell, atom, system, organism, organelle, tissue An organelle is a specialised subunit within a cell that has a specific function, and is usually separately enclosed within its own lipid bilayer.

12 You have been given 2 diagrams of eukaryotic cells They contain organelles that are visible with an electron microscope. Using textbooks label as many as you can

13 What do cells have organelles? A cell does a huge number of complex things. It is basically a factory. Why does your house need rooms? The cell does different things in different organelles. It is very similar to your body doing different things with different organs (e.g. your lungs breathe). In a cell mitochondria produce energy, ribosomes make protein....

14 Organelles make cells more efficient All the molecules, enzymes etc needed for each purpose can be found close together in each organelle e.g. all the reactants and enzymes needed for photosynthesis can be found in a chloroplast

15 You need to know the function of the main organelles Worksheet Cell Ultrastructure mainz.de/FB/Medizin/Anatomie/workshop/EM/EM ZelleE.html Electron micrographs - 6 min clip

16 Write down everything you know about the nucleus The nucleus - Contains the cells hereditary material - Controls the cells activities micrometers

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19 Nucleus - main parts 1. Nuclear envelope - double membrane. It’s outer membrane is continuous with the endoplasmic reticulum and often has ribosomes on its surface. It controls the entry and exit of materials and contains the reactions happening within it. 2. Nuclear pores - allows the passage of large molecules e.g. mRNA. About 3000 pores in each nucleus - each nm in diameter.

20 Nucleus - main parts 3. Nucleoplasm - the granular, jelly-like material that makes up bulk of the nucleus 4. Chromatin - the DNA found within the nucleoplasm - it makes up chromosomes. When the cell is not dividing chromosomes are not tightly coiled but are in a relaxed looser form known as chromatin 5. Nucleolus - manufactures ribosomal RNA and assembles the ribosomes

21 Nucleus - FUNCTIONS 1. Control centre - of the cell. It produces mRNA and hence protein. 2. Retains the genetic material - in the form of DNA or chromosomes 3. Manufactures ribosomal RNA and ribosomes

22 The mitochondrion 1. Rod shaped 1-10 micrometers in length 2. Double membrane - the outer one controls entry and exit of material. The inner membrane is folded to form cristae.

23 The mitochondrion 3.Cristae - extensions of inner membrane. They provide a large surface area for attachment of enzymes involved in respiration 3. Matrix - rest of mitochondria. semi-rigid material containing protein, lipids and traces of DNA which allows the mitochondria to control production of their own proteins. Enzymes involved in respiration are found in the matrix.

24 The mitochondrion - function Some stages of RESPIRATION happen in the mitochondria. They produce the energy-carrier molecule ATP Q. - why do muscle cells and epithelial cells have more mitochondria than say a skin cell?

25 The Endoplasmic reticulum (ER) Elaborate, 3- dimensional system of sheet-like membranes that spread throughout the cytoplasm - it is continuous with the outer nuclear membrane. The membranes enclose flattened sacs called cisternae 2 types of ER

26 Rough Endoplasmic reticulum (RER) Has ribosomes on the outer surfaces of membranes. Functions 1. To provide a large surface area for the synthesis of proteins and glycoproteins 2. To provide a pathway for the transport of materials, especially proteins throughout the cell.

27 Smooth Endoplasmic reticulum (SER) Lacks ribosomes on its surface and is often tubular. Functions 1. To synthesise, store and transport lipids 2. To synthesise, store and transport carbohydrates

28 Golgi Apparatus Similar to SER but more compact. It consists of a stack of membranes that make up flattened sacs or cisternae, with small rounded hollow structures called vesicles. The proteins and lipids produced by the ER are passed through the Golgi apparatus in strict sequence.

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30 Golgi Apparatus The Golgi modifies the proteins It adds non-protein components e.g. carbohydrate to them. It also labels them which allows them to be accurately sorted and sent to their correct destinations

31 Golgi Apparatus Once sorted the modified proteins and lipids are transported in vesicles which are pinched off from the ends of the Golgi cisternae. These vesicles move to the cell surface where they fuse with the membrane and release their contents to the outside

32 Golgi Apparatus - FUNCTIONS 1. Add carbohydrate to proteins to form glycoproteins 2. Produce secretory enzymes 3. Secrete carbohydrates, such as those used in making cell walls in plants 4. Transport, modify and store lipids 5. Form lysosomes Q. What kinds of cells will have very well- developed Golgi apparatus?

33 Lysosomes These are formed when the vesicles produced by the Golgi apparatus contain enzymes such as proteases and lipases. Q. Why are these enzymes isolated in lysosomes? Up to 50 different enzymes in each lysosome Up to 1.0 micrometers in diameter

34 Lysosomes - FUNCTIONS 1. Break down material ingested by phagocytic cells, such as white blood cells 2. Release enzymes to the outside of the cell (exocytosis) in order to destroy material around the cell 3. Digest worn out organelles so that the useful chemicals they are made of can be re-used Completely break down cells after they have died (autolysis) Q. Name 2 types of cells you might find a lot of lysosomes in

35 Ribosomes Small granules found in all cells either in the cytoplasm or associated with the RER. 2 Types 80S type - found in eukaryotic cells - 25 nm in diameter 70S type - found in prokaryotic cells - slightly smaller

36 Ribosomes - 2 subunits Each subunit contains ribosomal RNA and protein They occur in vast numbers - make up to 25% of the dry mass of a cell. VERY important in protein synthesis

37 Microvilli Finger-like projections of the epithelial cell. What do you think their main purpose is? To increase the surface area to allow more efficient absorption

38 Now do the following Answer Summary questions on Page 49 of text book References Glenn Toole, Susan Toole (2008). A2 Biology. Cheltenham: Nelson You Tube clips to watch - the inner life of a cell ( 3 mins) - Exploring the living cell - (3 mins) - Exploring the living cell - (3 mins) hhttp://www.youtube.com/watch?v=Ao9cVhwPg84&feature=related - voyage inside the cell (15 mins)(15 mins) - - good lecture about the cell (14 mins)


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