B2 Knowledge Test - Answers
1. Label these diagrams of cells:
Chloroplast
Cell membrane
Nucleus
Nucleus
Cell wall
Cell membrane
Cytoplasm
Vacuole
Cytoplasm
2. Complete this table to give the function of the following organelles:
Organelle
Cell
Membrane
Cell Wall
Chloroplast
Mitochondria
Vacuole
Function
Controls movement of substances in and out of the cell.
Supports the cell.
Absorbs LIGHT. Where photosynthesis takes place
Where respiration occurs.
Helps support the plant by keeping the cell rigid
3. Electron Microscope
4. Bacterial cell has plasmids, animal cell does not, bacterial cell has a flagellum, animal cell does not, bacterial
cell has a cell wall, animal cell does not, bacterial cell has a circular loop of DNA, animal cell has DNA in
chromosomes, animal cell has a nucleus, bacterial cell does not.
5. A section of DNA which codes for a specific protein.
6. Double helix – two strands held together by hydrogen bonds between complementary bases
7. A=T, G=C
8. A pairs with U instead of T. T is replaced by U in the mRNA.
9. Salt, water, washing up liquid, (protease)
10. Watson and Crick
11. Took Rosalind Franklins x ray photograph
12. To sequence all of the bases in the human genome.
13. Improved genetic testing for disorders; New ways of finding new genes that may increase risk of certain
diseases; New treatments and cures for diseases; New ways of looking at changes in the genome over time;
Personalised medicines that work with a particular genotype.
14. A circular loop of DNA.
15. Altering the DNA of an organism by inserting DNA from another organism into its genome.
16. Enzymes
17. Complete the table below to give one advantage and one disadvantage of Genetic Engineering for each
example:
Advantage
Disadvantage
Beta carotene in Golden Rice
Used to make vitamin A
Could cross breed with wild
Vitamin A will reduce death
rice and contaminate wild rice
and blindness.
DNA
Producing insulin
Production of herbicide
resistant crops
Can be used by vegans
Supply not affected by animal
diseases
Supply not affected by demand
for meat
Can be made in vast quantities
Cheaper
Reduces amount of crop
spraying
Levels of beta carotene in
Golden Rice might not be high
enough to make a difference
Can be expensive to buy
Produces sterile seeds so
farmers have to buy them
every year
Bacteria produce insulin slightly
differently so may not work for
some people
Herbicide resistant weeds can
develop
Cross pollination with wild
plants
Potential loss of biodiversity
18. Complete this table to compare mitosis and meiosis
Number of daughter cells
formed
Are the daughter cells identical
to the parent cell?
Do the daughter cells have
haploid or diploid nuclei?
Used for…
Mitosis
2
Meiosis
4
yes
No
diploid
Haploid
Growth and repair
Making gametes
19. Haploid gametes join to form a diploid zygote
20. The production of a genetically identical individual. An example of asexual reproduction.
21. Remove a diploid nucleus from a body cell; Enucleate an egg cell; Insert diploid nucleus into enucleated egg
cell; Stimulate the diploid nucleus to divide by mitosis; Implant into surrogate mother.
22. Discarded embryos from fertility treatment. Embryo destroyed in the process
23. .
Cloning
Embryonic stem cell research
Advantage
Can make a genetically
identical copy of an animal with
desirable characteristics.
Can be used to make copies of
GM animals to guarantee all
offspring have the trait.
Embryonic stem cells can
develop into almost every type
of human cell.
Bone marrow stem cells can be
used to treat leukaemia.
Adult stem cells may be used in
future instead of embryonic
stem cells.
Disadvantage
Cloned animals often die
young.
Cloned animals often age more
quickly.
Complicated process.
Embryonic stem cells can
come from leftover embryos
from fertility treatments.
Risk of rejection if not from a
patients own stem cells.
Could lead to tumours
forming.
24. The sequence of bases on the DNA
25. DNA double helix unzips; The complementary mRNA strand is made in the nucleus and passes out through a
pore; mRNA attaches to the ribosome; A triplet of bases on the mRNA (codon) code for a specific amino acid;
tRNA transfers amino acids to the ribosome.
26. A change in the sequence of bases in the DNA
27. Amino Acids
28. They have a specific shape, they have a specific sequence of Amino Acids
29. A biological catalyst
30. It speeds up its activity up to 40oC after which it denatures and stops working.
31. Enzymes only work at a specific pH. Either side of the optimum, it will not work as well.
32. Active site
33. The shape of the active site has changed
34. Digestion – Many enzymes break larger molecules down into smaller ones in digestion. This happens outside
of the body. Stain digesting enzymes in washing powders break down stain in clothes. Microorganisms
excrete enzymes onto food to break them down outside the body and then absorb the products.
35. DNA replication, protein synthesis
36. A process where all living organisms release energy from their food. Glucose + oxygen  Carbon Dioxide and
Water. Oxygen diffuses from air into blood and blood into cells. Glucose diffuses from gut into blood and
blood into cells. Carbon dioxide diffuses from cells to blood and blood to air, water diffuses from cell to
blood.
37. The movement of a substance from high to low concentration/down a concentration gradient. It is a passive
process.
38. It increases it because the body has a greater demand for oxygen and glucose, and produces more waste
carbon dioxide to be removed. The blood circulates these substances to and from the cells.
39. 4560cm3
40. When there is not enough oxygen available for aerobic respiration. After a period of rapid exercise. After
death.
41. Glucose  Lactic Acid
42. Excess post-exercise oxygen consumption. Required more oxygen to be paid back after a period of anaerobic
respiration.
43. Large surface area, contains chlorophyll to absorb light, stomata for gas exchange.
44. Water + Carbon dioxide  glucose + oxygen
45. Light intensity, CO2 concentration, temperature.
46. It increases up to a point where another factor will become limiting.
47. The movement of water through a plant.
48. By active transport using energy from the soil to the cells of the root
49. By osmosis from the soil to the cells of the root then up the xylem.
50. To transport glucose up and down the plant.
51. The movement of water from high water concentration to low water concentration across a semi permeable
membrane. .
52. Large surface area to increase water absorption.
53. Because fossils do not always form, because soft tissue decays, because many fossils are still to be found.
54. Suggests all vertebrates evolved from one common ancestor as there are similarities between bone
structure.
55. Divide, elongate, differentiate
56. .
Component
Red Blood Cell
Function
Transport oxygen
White Blood Cell
Plasma
Platelets
Fight infection
Transport CO2, hormones, glucose
Blood clotting
57. .
Carries oxygenated blood
pulmonary vein, aorta,
left ventricle, left atrium
Carries deoxygenated blood
Pulmonary artery, vena cava
right ventricle, right atrium,
58. Valves
59. Thicker wall
60. Artery – carries blood away from the heart, vein – carries blood to the heart, capillary – exchange of
substances between tissues.
61. Describe the function of each of the following parts of the digestive system:
Organ
Mouth
Function
Food broken up into smaller pieces, mixed with
saliva, starch digestion
Moves food to stomach by peristalsis
Mixes food with enzymes and acid
Absorption of food
Absorption of water
Makes enzymes
Makes bile, breaks down some substances
Stores bile
Oesophagus
Stomach
Small intestine
Large intestine
Pancreas
Liver
Gall bladder
62. Pushes food along the digestive system by muscular contraction. Peristalsis
63. Complete this table about digestive enzymes:
Enzyme Group
Carbohydrases
Proteases
Lipase
Example
Amylase
Pepsin
Function
Breaks starch into glucose
Breaks protein into amino acids
Digests fat into glycerol and
fatty acid
64. Emulsifying fats, neutralising stomach acid.
65. Large surface area, good blood supply, one layer of cells thick for efficient absorption