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Fact sheet B2.1 Cells and tissues Animal and plant cells 1. Are animal and plant cells eukaryotic or prokaryotic? 2. Name the type of cell below 3. Identify the parts of the cell (5) 4. Name the type of cell below 5. Identify the parts of the cell (8) Eukaryotic Animal cell 1. Cell membrane 2. Mitochondria 3. Cytoplasm 4. Nucleus 5. Ribosomes Plant cell 6. Cell Wall 7. Cell membrane 8. Cytoplasm 9. Mitochondria 10. Chloroplast 11. Nucleus 12. Ribosomes 13. Vacuole 6. Give the function of the cell membrane 7. Give the function of the nucleus Controls the passage of substances into and out of cells Controls the activities of the cell 8. Give the function of the cytoplasm Where most chemical reactions take place 9. Give the function of the mitochondria Where energy is released from aerobic respiration 10. Give the function of the ribosomes Where protein synthesis occurs 11. Give the function of the chloroplast Absorb light energy to make food 12. Give the function of the vacuole Filled with cell sap 13. Give the function of the cell wall and say what it’s made of (2) Strengthens the cell Made of cellulose Bacteria 14. Are bacteria cells eukaryotic or prokaryotic? 15. Name a type of single celled organism 16. Name the type of cell below 17. Identify the parts of the cell (5) 18. What do bacteria cells have instead of a nucleus? Specialised cells –animal cells 19. Give the 2 different ways that cells can be specialised (2) 1. State how a sperm cell is specialised, and explain how this enables it to carry out its function/s (2) 2. State how a muscle cell is specialised, and explain how this enables it to carry out its function/s(1) 3. State how a ciliated cell is specialised, and explain how this enables it to carry out its function/s (2) 4. State how a red blood cell is specialised, and explain how this enables it to carry out its function/s (2) Specialised cells –plant cells 5. State how a root hair cell is specialised, and explain how this enables it to carry out its function/s (3) 6. State how a leaf cell is specialised, and explain how this enables it to carry out its function/s (2) Prokaryotic Bacteria A bacterial cell 1. 2. 3. 4. 5. Genes NOT in a distinct nucleus Cell wall Flagellum (not always present) Cytoplasm Membrane A single DNA loop and there may be one or more small rings of DNA called plasmids Have a structure that other cells don’t (e.g. sperm cell has a tail) They can have LOTS of a particular part (e.g. muscle cells have LOTS of mitochondria) –flagellum for movement to reach the egg -lots of mitochondria for respiration to release energy for flagellum to move – lots of mitochondria for respiration to release energy for muscle contraction –cilia to move substances along tubes (e.g. egg along oviduct, mucus out of airways) -lots of mitochondria for respiration to release lots of energy for movement of cilia –full of haemoglobin so can carry lots of oxygen -no nucleus so there is more space for haemoglobin -has a large surface area so that it can absorb lots of minerals and water -long thin hair so it has a larger surface area to absorb more of the substances it needs -no chloroplasts because roots are below the ground (don’t carry out photosynthesis), means higher surface area for minerals and water -lots of chloroplasts to carry out lots of photosynthesis and produce lots of glucose -lots of ribosomes to produce lots of protein Microscopy 1. What are the two types of microscope? 2. Which microscope has a higher magnification and resolving power? 3. What is the calculation for magnification? 4. Put the following measurements into size order, starting with the smallest: mm, µm, nm, cm 5. What do the measurements above represent? Mitosis and the cell cycle 1. Where are chromosomes found in a cell? 2. What are chromosomes made of? 3. Where are genes found? 4. What happens in the first stage of the cell cycle? (3) 5. What happens in the second stage of the cell cycle? (2) 6. What happens in the third stage of the cell cycle? 7. How many cells are produced at the end of mitosis? 8. What can you say about the cells produced by mitosis? 9. Why is mitosis important for multicellular organisms? (2) Stem cells and differentiation 1. What is a stem cell? 2. What happens when a cell differentiates? 3. Why do cells differentiate during the development of multicellular organisms? 4. Name the 2 places where human stem cells are found 5. What could human stem cells potentially be used for and why? (2) 6. When do most types of animal cells differentiate? 7. When do most types of plant cells differentiate? 8. What kind of tissue in plants can differentiate into any type of plant cell, throughout the life of the plant? 9. Why would we want to clone plants quickly and economically? -light microscope -electron microscope Electron microscope magnification = size of image size of real object nm, µm, mm, cm mm = millimetre, µm = micrometre nm = nanometre, cm = centimetre In the nucleus DNA Large numbers on each chromosome The cell grows The number of organelles increases (e.g. ribosomes and mitochondria) The DNA replicates MITOSIS –one set of chromosomes is pulled to each end of the cell The nucleus divides The cytoplasm and cell membranes divide (to form two identical cells) 2 They are identical to each other For growth and development An undifferentiated cell which is capable of giving rise to many more cells of the same type It becomes specialised/ adapted to carry out a specific function To become specialised so that they can carry out different functions Embryos and adult bone marrow To treat conditions such as paralysis and diabetes As they can be made to differentiate into many different types of cells, e.g. nerve cells At an early stage They retain the ability to differentiate throughout life Meristem tissue Rare species can be cloned to protect from extinction Crop plants with special features (such as disease resistance) can be cloned to produce large numbers of identical plants for farmers 10. What is cell division mostly restricted to in mature animals? (2) 11. What is produced in therapeutic cloning? 12. Why do we do therapeutic cloning? 13. Give an example of the potential risks that are associated with the use of stem cells 14. Why might some people object to the use of stem cells? (2) • Repair of tissues • Replacement of lost/ dead cells An embryo with the same genes as the patient (a clone) To obtain stem cells (from the embryo) that will not be rejected by the patient’s body which means they can be used for medical treatment Transfer of viral infection Ethical or religious objections Diffusion, active transport and osmosis 1. How do dissolved substances move into and out of cells across a cell membrane? 2. Define ‘diffusion’ (2) 3. Name 3 factors that would affect the rate of diffusion 4. Give two examples of substances diffusing into and out of cells by diffusion 5. As organisms get larger the surface area to volume ratio gets… A single celled organism has a ________ surface area to volume ratio. This allows for direct ________ of substances into and out of the cell. A complex _______ ________ is not required to meet the _____ of the organism. Why do multicellular organisms need exchange surfaces and a transport system? 6. 7. 8. The effectiveness of an exchange surface is increased by (4) Diffusion 1. The net movement of particles in a gas or liquid 2. from an area of higher concentration to an area of lower concentration. Concentration gradient (difference in concentrations) Temperature The surface area of the membrane Oxygen and carbon dioxide in gas exchange (between the lungs and the blood) Urea from cells into the blood plasma for excretion in the kidney smaller Large Diffusion Transport system needs Because diffusion alone is not sufficient to meet the needs of the organism as the surface area to volume ratio is too small. Having a large surface area A membrane that is thin, to provide a short diffusion path (in animals) having an efficient blood supply (in animals, for gas exchange) being ventilated Two factors which cause organisms to need specialised exchange surfaces are: (2) 10. Two ways that dissolved substances can move are: (2) 11. Water moves across boundaries by: ■ increased size ■ increased complexity 12. Osmosis is the diffusion of water from a _________ to a more ___________ solution through a _________ ________ ________(4) 13. Differences in the concentrations of the solutions ________ and _________ a cell cause water to move into or out of the cell by osmosis. 14. What is required to absorb a substance against a concentration gradient? (2) 15. A process which requires energy to move substances is called? 16. Active transport enables cells to absorb _______ from very dilute solutions. In humans: dilute (1) concentrated (1) partially permeable (1) membrane (1) Inside and outside (1) 9. ■ diffusion ■active transport Osmosis Energy (1) from respiration (1) Active transport ions 17. the surface area of the lungs is increased by the ____________ the surface area of the small intestine is increased by __________. 18. The villi provide a large surface area with an extensive network of capillaries. What is their function? In plants: 19. What increases the surface area of i) Roots ii) Leaves alveoli villi To absorb the products of digestion by diffusion and active transport. Root hairs flattened shape and internal air spaces (2)