B1-Cell Level Systems

Question 1

36.) List four features that animal and plant cells have in common.

Answer 1

1. ) Nucleus - this contains chromosomes which is coiled up DNA and the nucleus controls all of the cells reactions.
2. ) Mitochondria - they contain enzymes and are the site of respiration
3. ) Cytoplasm - This is were chemical reactions occur and it is a gel-like substance.
4. ) Cell membrane - it is a selective barrier which allows thing to go in and out of it, it also contains receptor molecules which allows for cell communication and it holds everything together.

Question 2

37.) What do plant cells have that animal cells don’t?

Answer 2

1. ) they have cell walls made of cellulose which helps to support the structure.
2. ) Chlorophyll which is made up of chloroplasts and this is where photosynthetic reactions occur.
3. ) They have vacuoles which contain substances needed for the plant to survive.

Question 3

1.) list four features that animal and plant cells have in common.

Answer 3

1. )a.) Cytoplasm
   b. ) Cell membrane
   c. ) Nucleus
   d. ) Mitochondria

Question 4

2.) Give two sub-cellular structures that are present in prokaryotic cells but not eukaryotic cells.

Answer 4

2. )a.) Plasmid rings

b. ) Chromosomal DNA

Question 5

3.) How have electron microscopes been able to increase our understanding of sub-cellular structures?

Answer 5

3.) They let us see much smaller things in more detail allowing us to see sub-cellular structures like plasmids and viruses in high resolution and high magnification.

Question 6

4.) Why is it important to take a thin slice of a sample before looking at it under a light microscope?

Answer 6

4.) It allows light to pass through the specimen allow you to observe it to thick and light won’t pass through it and you can’t see it.

Question 7

5.) How can you calculate the magnification of an image if you dont know what lenses are used.

Answer 7

5.) image size / actual size

Question 8

6.) Give the initials of the four bases present in DNA

Answer 8

G,C and A,T

Question 9

7.) Describe the structure of a nucleotide

Answer 9

7.) pentose sugar and phosphate backbone and a base in a double helix structure.

Question 10

8.) What is a gene?

Answer 10

8.)A section of DNA which codes for a particular protein.

Question 11

9.) What is a triplet code

Answer 11

9.) Three bases or codon

Question 12

10.) What is the process of making mRNA from DNA called ?

Answer 12

10.) Transcription the process of making tRNA is called translation.

Question 13

11.) In what part of the cell are amino acids joined together to make a protein?

Answer 13

11.) Cytoplasm in the ribosomes

Question 14

12.) Draw a diagram to show how the ‘lock and key’ mechanism of enzymes work.

Answer 14

12.) X <

W

Question 15

13.) What does it mean when an enzyme has denatured ?

Answer 15

13.) It means the enzyme has lost its shape and the substrate no longer fits the active site.

Question 16

14.) Sketch a graph to show different scenarios and how they effect enzymes.

Answer 16

14. ) a.) Temperature
    b. ) Enzyme to substrate concentration
    c. ) pH (see page 18)

Question 17

15.) Give two things that you could measure when investigating the rate of an enzyme in a controlled reaction.

Answer 17

15. )a.) How fat the product appears

b. ) How fast the substrate disappears.

Question 18

16.) Give two variables that need controlling when investigating the effect of pH on an enzyme-controlled reaction.

Answer 18

16. )a.) Enzyme to substrate concentration

b. ) Temperature

Question 19

17.) What is respiration?

Answer 19

17.) the process of transferring energy from the break down of glucose. It happens in the mitochondria.

Question 20

18.) Is respiration an exothermic or endothermic reaction?

Answer 20

18.) exothermic

Question 21

19.) Name the type of respiration that requires oxygen.

Answer 21

19.) Aerobic

Question 22

20.) Give an example of when lactic acid would be produced as a product of respiration.

Answer 22

20.) When animals breathe anaerobically

glucose —> lactic acid

Question 23

21.) Which form of respiration transfers more energy per one glucose molecule?

Answer 23

21.) Aerobic, because it transfers 32 ATP per glucose molecule and anaerobic only produces 2 ATP per glucose.

Question 24

22.) Briefly describe an experiment to show that carbon dioxide is a product of respiration.

Answer 24

22.)a.) boil germination beans to kill them get two test tubes and put hydrogen-carbonate indicator in both of the tubes get some gauze and put it in the test tube and place the dead beans in one of the test tubes on top of the gauze and live beans in the other the live beans the solution will go from red to yellow the dead will stay red.

Question 25

23.) What type of polymer do you get when you join simple sugars together?

Answer 25

23.) Complex carbohydrates like starch and glycogen

Question 26

24.) What units are lipids made of ?

Answer 26

24.) one glycerol per three fatty acids.

Question 27

25.) What can you conclude if a test turns blue-black colour when Iodine is added?

Answer 27

25.) Starch is present.

Question 28

26.) How can you test for lipids?

Answer 28

26. ) a.) emulsion test: shake the substance with ethanol until dissolves then add water if a milky emulsion is made a lipid is present b. ) red sudan test: add it and if a fat is present it goes red.

Question 29

27.) How do you test for proteins?

Answer 29

27.) Biuret test : add sodium hydroxide to the protein solution and add copper (II) sulfate if it turns purple it has protein if it stays blue it doesn't contain a protein.

Question 30

28.) How do you test for sugars not including the iodine test.

Answer 30

28. )a.) Reducing sugars - Benedict reagent: add Benedict reagent to the sample and place it in a water bath at 75oC it should turn from blue to red if it is really strong. b. ) Non-reducing sugars - Benedict reagent: the same as above just add dilute hydrochloric acid a coloured precipitate should form like above and the same rules apply.

Question 31

29.) In what part of the cell does photosynthesis take place?

Answer 31

29.) Chloroplasts

Question 32

30.) Is photosynthesis endothermic or exothermic

Answer 32

30.) endothermic

Question 33

31.) What are the two stages of photosynthesis?

Answer 33

31. )a.) The light splits water into H ions and oxygen gas | b. ) The H ions join onto the carbon dioxide to form glucose.

Question 34

32.) What are the three factors of photosynthesis and how do they effect the rate?

Answer 34

32. )a.) Light intensity: At first it increases but then it get to a limit where something else is effecting the rate of photosynthesis as there isn't enough water or carbon dioxide. b. ) Carbon Dioxide: Again the same principal it increases but get to a point where it no longer matters. c. ) Temperature: Its like enzymes it increases as the collision rate increases due to more energy but too hot the enzymes begin to denature.

Question 35

33.) What is the relationship between light intensity and distance from the plant?

Answer 35

33.) light intensity is inversely proportional to 1 over the distance squared.

Question 36

34.) How could you investigate the effect of carbon dioxide on the rate of photosynthesis?

Answer 36

34.) You could dissolve different amounts of sodium hydrogen-carbonate in the water which gives of carbon dioxide and measure how much oxygen is made from the plants.

Question 37

35.) Draw graphs for the limiting factors of photosynthesis.

Answer 37

35. )a.) Temperatures b. ) Light intensity c. ) Carbon dioxide levels