1. Which process decreases when the human body · PDF file1 1. Which process decreases when the human body temperature decreases? A. Blood flow to the internal organs B. Secretion

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1. Which process decreases when the human body temperature decreases?

A. Blood flow to the internal organs

B. Secretion of sweat

C. Secretion of insulin

D. Shivering (Total 1 mark)

2. Which organ secretes enzymes that are active at a low pH?

A. Mouth

B. Pancreas

C. Stomach

D. Liver (Total 1 mark)

3. Which vessel carries deoxygenated blood?

A. The pulmonary artery

B. The coronary artery

C. The aorta

D. The pulmonary vein (Total 1 mark)

4. Anti-diuretic hormone has its main effect on which part of the nephron?

A. Proximal tubule

B. Bowman’s capsule

C. Loop of Henle

D. Collecting duct (Total 1 mark)

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5. Why do antibiotics kill bacteria but not viruses?

A. Antibiotics stimulate the immune system against bacteria but not viruses

B. Viruses have a way of blocking antibiotics

C. Viruses are too small to be affected by antibiotics

D. Viruses do not have a metabolism (Total 1 mark)

6. During the process of translation which of the following statements describes the relationship between nucleic acids?

A. Anticodons on mRNA bind to complementary codons on DNA.

B. Anticodons on tRNA bind to complementary codons on mRNA.

C. Bases on DNA bind to complementary bases on mRNA.

D. A single strand of mRNA is produced from the DNA in the nucleus. (Total 1 mark)

7. In thermoregulation, what would happen over a short period of time in each of these areas, if a person was placed in water at 15°C ?

Peripheral circulation Sweat glands Liver Skeletal muscle

A Increased blood flow Increased secretion Decreased temperature Decreased shivering

B Decreased blood flow Decreased secretion Decreased temperature Increased shivering

C Decreased blood flow Increased secretion No change in temperature Increased shivering

D Decreased blood flow Decreased secretion No change in temperature Increased shivering (Total 1 mark)

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8. What is the function of DNA polymerase I?

A. To add appropriate nucleotides in the 3′ → 5′ direction

B. To remove the RNA primers and replace them with DNA

C. To join together the Okazaki fragments

D. To join together both strands of DNA to the histones (Total 1 mark)

9. What is the role of active transport in the transmission of nerve impulses by neurones?

A. Propagates an action potential by pumping sodium ions across the membrane out of the neurone.

B. Propagates an action potential by pumping sodium ions across the membrane into the neurone.

C. Initiates the action potential needed for the transmission of an impulse by pumping calcium ions out of the endoplasmic reticulum.

D. Establishes the resting potential needed for the transmission of an impulse by pumping sodium and potassium ions across the membrane.

(Total 1 mark)

10. According to the induced fit model of enzyme function, which of the following statements is correct?

A. Active sites on enzymes are specific to a single substrate.

B. The shape of the active site can be changed by the binding of an allosteric inhibitor.

C. The binding of the substrate changes the shape of the active site slightly.

D. Competitive inhibitors can change the shape of enzymes. (Total 1 mark)

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11. What is a difference between the sense and antisense strands of DNA?

A. Nucleotides are linked to the sense strand by hydrogen bonding during transcription, but not to the antisense strand.

B. The sense strand has the same base sequence as tRNA, but the antisense strand does not.

C. Nucleotides are linked to the antisense strand by hydrogen bonding during transcription, but not to the sense strand.

D. The antisense strand has the same base sequence as mRNA but the sense strand does not. (Total 1 mark)

12. In the menstrual cycle in humans, which hormone causes the wall of the follicle to develop after ovulation and to secrete more progesterone?

A. Estrogen

B. FSH

C. LH

D. Oxytocin (Total 1 mark)

13. The walls of blood capillaries in the kidney are fenestrated. How does the fenestration of these capillaries help in the production of urine?

A. A larger volume of fluid can be filtered out of the blood per minute.

B. Small molecules are allowed through but not large ones.

C. Higher blood pressures can be tolerated without damage to the capillaries.

D. Phagocytes are able to escape from the capillaries and prevent kidney infections. (Total 1 mark)

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14. When an impulse arrives at a synapse which way do calcium ions move?

A. Into the synaptic knob from the synaptic cleft

B. Into the post synaptic nerve cell from the synaptic cleft

C. Out from the synaptic knob into the synaptic cleft

D. Out from the post synaptic nerve cell into the synaptic cleft (Total 1 mark)

15. Women should periodically have a Pap smear test performed to detect cervical cancer. Which letter indicates the cervix in the diagram below?

(Total 1 mark)

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16. The diagram below shows a channel protein in a membrane. Which parts of the surface of the protein would be composed of polar amino acids.

A. I and II only

B. II and III only

C. III and IV only

D. I and IV only (Total 1 mark)

17. The diagram below shows a short section of DNA molecule before and after replication. If the nucleotides used to replicate the DNA were radioactive, which strands in the replicated molecules would be radioactive?

A. II and III only

B. I and III only

C. I and II only

D. I, II, III and IV (Total 1 mark)

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18. Which structure represents an amino acid?

(Total 1 mark)

19. Which organ secretes FSH (follicle-stimulating hormone)?

A. Ovary

B. Testis

C. Pituitary gland

D. Placenta (Total 1 mark)

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20. What does the body use to control the heartbeat?

I. Adrenalin

II. Pacemaker

III. Nerves from brain

A. II and III only

B. I and II only

C. I, II and III

D. I and III only (Total 1 mark)

21. What is removed to form mature eukaryotic mRNA?

A. RNA primers

B. Exons

C. RNA polymerases

D. Introns (Total 1 mark)

22. What is in vitro fertilization?

A. Fertilization using donated sperm

B. Artificial fertilization of an egg inside the body

C. Fertilization of an egg outside the body

D. Cloning technique to help couples conceive (Total 1 mark)

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23. Do the levels of progesterone and FSH increase or remain low during the first few days of the menstrual cycle?

A. Progesterone and FSH both remain low.

B. Progesterone remains low but FSH increases.

C. Progesterone increases but FSH remains low.

D. Progesterone and FSH both increase. (Total 1 mark)

24. After depolorization what happens to restore the resting potential?

A. Sodium channels open and sodium ions diffuse out of the neuron

B. Potassium channels open and potassium ions diffuse into the neuron

C. Potassium channels open and potassium ions diffuse out of the neuron

D. Sodium channels open and sodium ions diffuse into the neuron (Total 1 mark)

25. The complex structure of proteins can be explained in terms of four levels of structure, primary, secondary, tertiary and quaternary.

(a) Primary structure involves the sequence of amino acids that are bonded together to form a polypeptide. State the name of the linkage that bonds the amino acids together.

..................................................................................................................................... (1)

(b) Beta pleated sheets are an example of secondary structure. State one other example.

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(c) Tertiary structure in globular proteins involves the folding of polypeptides. State one type of bond that stabilizes the tertiary structure.

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(d) Outline the quaternary structure of proteins.

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(Total 5 marks)

26. The surface area to volume ratio is an important variable in determining biological structure.

(a) Explain the importance of the surface area to volume ratio as a factor limiting cell size.

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(b) Define the term absorption.

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(c) State one feature of alveoli that adapts them to gas exchange.

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(d) Figure 1 below shows a cross-section through the small intestine and Figure 2 an enlarged longitudinal section through a single villus.

Figure 1 Figure 2

[Source: adapted from M Roberts et al., [Source: adapted from Taylor et al., Advanced Biology, Nelson, 2000, page 185] Biological Science 1 Cambridge University Press, 1997, page 244]

Using these diagrams, outline three ways in which the structure of the small intestine is related to its function of absorbing food.

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(Total 7 marks)

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27. Draw the structure of a fatty acid.

(Total 1 mark)

28. The information needed to make polypeptides is carried in the mRNA from the nucleus to the ribosomes of eukaryotic cells. This information is decoded during translation. The diagram below represents the process of translation.

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(a) Annotate the diagram to show the direction in which the ribosome moves during translation.

(1)

(b) State the name of the next amino acid which will attach to the polypeptide.

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(c) Explain how the amino acid was attached to the tRNA.

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(d) Identify two locations within a eukaryotic cell where translation occurs.

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(Total 6 marks)

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29. (a) Explain how the skin and mucous membranes prevent entry of pathogens into the body.

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(b) Explain why antibiotics are used to treat bacterial but not viral diseases.

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(Total 5 marks)

30. Describe homeostasis in relation to blood glucose concentration in humans. (Total 6 marks)

31. Explain the roles of LH and FSH in the menstrual cycle, including the timing of their secretion during the cycle.

(Total 6 marks)

32. Discuss the ethical issues of in vitro fertilisation (IVF) in humans. (Total 8 marks)

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33. Draw a labelled diagram of the human elbow joint.

(Total 4 marks)