B4 Life processes Q1 Question Label the animal cell. B4 Life processes. Question: Label the plant cell.

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1 Q1 Label the animal cell. Q2 : Label the plant cell. A cell membrane, B cytoplasm, C nucleus, D- mitochondria A cell wall, B vacuole, C chloroplast, D nucleus, E cell wall, F cytoplasm, G - mitochondria Q3 What are the functions of the following cell parts: Nucleus, cytoplasm, cell membrane, mitochondria? Nucleus: contains DNA (instructions for making proteins) Cytoplasm: enzymes are made here and some reactions in respiration occur here. Cell membrane: holds the cell together and controls what goes in and out. Mitochondria: contain enzymes for the reactions in aerobic respiration. Q4 Name three things that plant cells have that animal cells do not. Cell wall Vacuole Chloroplasts

2 Q5 True or false, yeast have mitochondria and a nucleus? True Q6 What type of cells have a cell wall but no nucleus? Bacterial cells Q7 Give a definition of an enzyme. Enzymes are proteins that speed up chemical reactions. Q8 Describe the lock and key model. Every enzyme has an active site where the substrate joins on to the enzyme. The active site is a specific shape and the substrate must be the correct shape to fit into it just like a key fits into a lock.

3 Q9 Name two things that can affect how quickly an enzyme works. Temperature ph (Could also have concentration of enzyme or substrate). Q10 Describe the effect of temperature on the rate of an enzyme controlled reaction. A higher temperature initially increases the rate of reaction. The rate of reaction will increase until the optimum temperature is reached, after this the rate of reaction will decrease. Q11 Why does a high temperature affect the rate of enzyme controlled reactions? If the temperature is too hot, some of the bonds that hold the enzyme together break. The change in shape of the active site means that the substrate no longer fits in and the enzyme won t work. The enzyme is denatured. Q12 What is an active site? The part of the enzyme where the substrate fits in.

4 Q13 Why are enzymes important? Give an example. Without enzymes the chemical reactions that take place in cells would happen too slowly. Examples could include respiration, photosynthesis, digestion or any other process that involves chemical reactions. Q14 What is a denatured enzyme and how does it happen? One where the active site has changed shape. This is irreversible and could be caused by the temperature being too high or the wrong ph. Q15 Name three things that the energy released by respiration is used for. Movement Active transport Synthesis of large molecules Q16 What is respiration? NOT BREATHING!! Respiration is a series of chemical reactions that release energy by breaking down large food molecules.

5 Q17 What type of respiration releases more energy per glucose molecule? Aerobic Q18 What is the word equation for aerobic respiration? Glucose + Oxygen Carbon + Water (+ Energy dioxide released) Q19 What is the balanced symbol equation for aerobic respiration? Q20 Give an example if when human cells respire anaerobically. C 6 H 12 O 6 + 6O 2 6CO 2 + 6H 2 O When you do vigorous exercise not enough oxygen can be supplied to muscle cells for aerobic respiration.

6 Q21 What are the products of anaerobic respiration in: a) Muscle cells b) Yeast Q22 Briefly describe why yeast is useful for making bread. a) Lactic acid b) Ethanol and carbon dioxide Yeast ferment the carbohydrate in flour and release carbon dioxide which makes the bread rise. Q23 Describe the process of photosynthesis. Q24 What is the word equation for photosynthesis? A series of chemical reactions which use energy from sunlight to produce food. Carbon dioxide + water sunlight Glucose + oxygen

7 Q25 What is the balanced symbol equation for photosynthesis? 6CO 2 + 6H 2 O sunlight C 6 H 12 O 6 + 6O 2 Q26 Explain what is meant by a limiting factor. A factor that is in short supply and can stop the rate of reaction from happening any faster. Q27 Name three factors that can limit the rate of photosynthesis. Light Carbon dioxide Temperature Q28 Describe three ways in which plants use the glucose that is produced in photosynthesis. Respiration To make chemicals for growth (e.g. cellulose) Stored as starch

8 Q29 Describe how to take a transect. Run a tape measure between two fixed points. Start at one end and move along collecting data until the end. Examples of data: percentage cover or species distribution. Q30 Describe how you might use a quadrat when investigating plants. A quadrat can be used to survey the plants present in a square metre. Any plants or animals present within the area of the quadrat are recorded. Quadrats are positioned randomly to remove bias and allow for reliable comparison between locations. Q31 What is an identification key? Q32 What is diffusion? A series of questions to help you identify a species. Each question narrows down your options until you are left with just one. Diffusion is the movement of particles from a region of high concentration to a region of low concentration. It takes place in liquids and gases.

9 Q33 Give two examples of chemicals that can move in or out of leaf cells by diffusion. Carbon dioxide Oxygen Q34 What is osmosis? The movement of water molecules from an area of high concentration to a region of low concentration across a partially permeable membrane. Q35 Give two ways in which active transport differs from diffusion. Q36 Explain how osmosis and diffusion are different. Active transport requires energy. Active transport moves substances from a region of low concentration to a region of high concentration. Osmosis only involves water molecules. Osmosis needs a partially permeable membrane.