biosci107 2010 exam

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VERSION25981025 - 2 - BIOSCI 107 FC

CONTINUED

SECTION A: THEORY

MULTIPLE CHOICE QUESTIONS

TEST VERSION CODE: 2598102550 marks

Recommended time: 60 minutes

Choose the ONE correct answer from the alternatives provided

Question 1: Membrane transport proteins are proteins that:

1. span the lipid bilayer.

2. contain hydrophilic residues that interface with the lipid bilayer.

3. do not interact with the cytoskeleton.

4. can be removed from the bilayer using high salt conditions.

5. are associated with the surface of the lipid bilayer.

Question 2: The lipid bilayer:

1. has electrical properties that mimic those of a capacitor.

2. is not permeable to water.

3. is formed mainly by a bilayer of cholesterol molecules.

4. has a low permeability to steroids.

5. contains a hydrophilic core which is impermeable to ions.

Question 3: The diffusion of carbon dioxide across cell membranes:

1. is mediated by haemoglobin.

2. is a form of non-mediated transport.

3. utilises the energy of the sodium gradient to drive cellular inux.

4. is an active process that utilises ATP.

5. is via a sodium dependent antiporter.

Question 4: The uptake of glucose by muscle cells:

1. occurs across the basolateral membrane.

2. utilises energy stored in the sodium gradient.3. is driven by the electrochemical gradient for glucose.

4. is maintained by the conversion of glucose to glucose-6-phosphate in the

cytoplasm.

5. occurs via a non-saturable process.

Question 5: Considering the ion gradients across a cell membrane:

1. a channel would mediate sodium ow out of a cell.

2. sodium/hydrogen exchange would lead to a decrease in intracellular pH.

3. active transport is required to accumulate potassium in cells.

4. a channel would mediate calcium movement out of a cell.

5. amino acid accumulation can be coupled to sodium movement out of a

cell.

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CONTINUED

Question 6: The skin:

1. has low resistance tight junctions.

2. contains numerous endocrine glands.

3. contains transitional epithelial cells.4. is an example of an absorptive epithelial tissue.

5. is a stratied squamous epithelium.

Question 7: Transepithelial secretion of a solute:

1. is initiated by the basolateral entry of the solute.

2. involves a transcellular ux of counter ions to preserve electroneutrality.

3. occurs from the blood to the lumen.

4. only occurs via the paracellular pathway.

5. involves the solute exiting the epithelial cells via the basolateral

membrane.

Question 8: Transport via the paracellular pathway is:

1. governed by the electrical resistance of the tight junctions.

2. against the laws of diffusion.

3. increased in the gut in a proximal to distal direction.

4. hormonally regulated.

5. independent of the transcellular transport pathway.

Question 9: Glucose diffusion across the basolateral membrane of an epithelial cell:

1. utilises energy stored in the sodium gradient.

2. does not exhibit saturation.

3. is always directed out of the cell.

4. is driven by the electrochemical gradient for glucose.

5. depends on the direction of the glucose concentration gradient.

Question 10: Glucose/galactose malabsorption syndrome:

1. decreases the osmolarity of the lumen of the small intestine.

2. induces secretory diarrhoea.

3. is caused by a genetic mutation to the facilitative glucose transporter.

4. is a common genetic disease.

5. can be treated by utilisation of an alternative carbohydrate uptakepathway.

Question 11: In patients with cystic brosis:

1. secretory diarrhoea is a clinical symptom.

2. the uptake of chloride ions is defective.

3. there is a failure of chloride reabsorption in their sweat ducts.

4. isotonic uid secretion is normal.

5. the intracellular signalling pathways that regulate CFTR are defective.

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CONTINUED

Question 18: Drug therapy for HIV/AIDS typically includes inhibitors for which of the

following HIV proteins?

1. the integrase, protease and the reverse transcriptase

2. the integrase and the protease

3. the reverse transcriptase and the protease

4. GP41 and the protease

5. GP120 and the integrase

Question 19: Which of the following is TRUE?

1. A haemoglobin molecule has 4 amino acid chains and binds 2 oxygen

atoms.

2. Human serum albumin has 4 amino acid chains and 2 identical binding

sites.

3. An IgG immunoglobulin molecule has 4 identical antigen binding sites.

4. A haemoglobin molecule is predominately alpha-helical.

5. An IgG immunoglobulin molecule is predominately alpha-helical.

Question 20: Formed elements in the blood that are biconcave discs about 7-8 m in

diameter are:

1. small lymphocytes.

2. erythrocytes.

3. brinogen.

4. blast cells that should not be present in circulation.

5. platelets.

Question 21: Which of the following mammalian defenses against invading pathogens is a

specic defense mechanism?1. Anti-microbial proteins.

2. The skin.

3. The immune system.

4. The inammatory process.

5. The mucous membranes.

Question 22: Histamine released in the local inammatory response has which of the

following effect(s)?

1. Attracts erythrocytes to the infection site.

2. Attracts T-lymphocytes to the infection site.

3. Attracts phagocytes to the infection site.

4. Attracts plasma cells to the infection site.

5. All of the options are correct.

Question 23: Why can a normal immune response be described as polyclonal?

1. Diverse antibodies are produced for different epitopes of a specic

antigen.

2. Multiple immunoglobulins are produced from descendants of a single B

cell.

3. The generation of an immune response requires many different types of

cells.4. Macrophages, T cells, and B cells are all involved in normal immune

response.

5. Blood contains many different antibodies to many different antigens.

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CONTINUED

Question 24: Which of the following cell types is responsible for initiating a secondary

immune response?

1. mast cells2. B cells

3. stem cells

4. memory cells

5. macrophages

Question 25: The resting membrane potential in neurons is mainly affected by the

permeability of the cell membrane to K+and Na+ions. At the resting state

(i.e. when no action potentials are red), the permeability ratio PNa+

/P

K+is

approximately:

1. 1/1000.2. 1/40.

3. 1/10.

4. 1/100.

5. 1/1.

Question 26: The equilibrium potential for Na+(ENa+

) represents the point at which:

1. the efux of Na+along its electrical gradient is balanced by the inux of

Na+along its electrical gradient.

2. the inux of Na+along its concentration gradient is balanced by the efux

of Na

+

along its electrical gradient.3. the inux of Na+along its concentration gradient is balanced by the efux

of Na+ along its concentration gradient.

4. the activity of Na+/ K+ATPase is at its maximum.

5. there is no potential difference between the inside and outside of the cell.

Question 27: The amplitude of action potentials in neurons is approximately:

1. 100 mV.

2. 1 mV.

3. 10 mV.

4. 1000 mV.

5. 100 V.

Question 28: The duration of action potentials in neurons (not including the duration of after-

hyperpolarisation, AHP) is approximately:

1. 1000 ms.

2. 1 ms.

3. 10 ms.

4. 1 sec.

5. 0.1 ms.

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CONTINUED

Figure 1

Question 29: Figure 1 above shows an action potential recorded in the axon. What is

happening during stage 3?

1. Activation of voltage-gated K+channels.

2. Cell membrane repolarisation due to activation of Na-K ATPase (Na+/ K+pump).

3. Rapid inux of K+ ions into the cell.

4. Activation of voltage-gated Na+channels.

5. Rapid inux of Na+ions into the cell.

Question 30: Continuous (non-saltatory) conduction of an action potential along nerve bres:

1. occurs only in myelinated axons.

2. occurs only in unmyelinated axons.

3. occurs only in the central nervous system.

4. occurs only in the peripheral nervous system.5. is faster than in nerve bres in which action potentials are conducted in

saltatory way.

Question 31: The conduction velocity in unmyelinated nerve bres is approximately:

1. 100 m/sec.

2. 1000 m/sec.

3. 10 m/sec.

4. 1 m/sec.

5. 10000 m/sec.

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CONTINUED

Question 32: Action potentials are usually propagated in only one direction along an axon

because:

1. both Na+and K+voltage-gated channels open in one direction.

2. ions can ow along axons only in one direction.

3. the nodes of Ranvier conduct current only in one direction.

4. the brief absolute refractory period prevents opening of voltage-gated Na+

channels.5. the axon hillock has a higher (i.e. more negative) membrane potential than

axon terminals.

Question 33: An increased amplitude of Excitatory Postsynaptic Potentials (EPSPs) can be

observed when excitatory synapses located on a single neuron are activated

repeatedly at short intervals. This process is called:

1. dendritic summation.

2. spatial summation.

3. temporal summation.

4. dendritic facilitation.5. postetanic potentiation.

Question 34: Excitatory Postsynaptic Potentials (EPSPs):

1. are usually evoked in neurons by GABA.

2. are effective in depolarising the trigger zone (axon hillock) to threshold

and evoking action potentials when produced by activation of only one

excitatory synapse.

3. are produced by opening of channels in the postsynaptic membrane that

are permeable to several cations (e.g. Na+, K+and often Ca2+).

4. are produced in neuronal cell bodies but not in dendrites.

5. cause hyperpolarisation of the postsynaptic membrane.

Question 35: Inhibitory Postsynaptic Potentials (IPSPs):

1. are produced in dendrites but not in neuronal cell bodies.

2. are evoked by glutamate.

3. can be evoked also in striated muscle bres.

4. are produced by opening of channels in the postsynaptic membrane that

are permeable to K+or Cl-.

5. cause depolarisation of the postsynaptic membrane.

Question 36: All the following electrical changes in neurons are graded events, EXCEPT: 1. depolarisation evoked by electrical stimuli.

2. receptor potentials.

3. IPSPs.

4. EPSPs.

5. action potentials.

Question 37: Which of the following is a neuropeptide (as opposed to a classical

neurotransmitter)?

1. acetylcholine

2. substance P3. GABA

4. dopamine

5. glutamate

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CONTINUED

Question 38: In a skeletal muscle bre:

1. adjacent sarcomeres are delineated by the A-bands.

2. sarcomeres are activated by Ca2+entering via L-type Ca2+channels.

3. sarcomeres are independently activated.

4. sarcomeres respond to stretch by decreasing force production.5. none of the other options is correct.

Question 39: In type 2b skeletal muscle bres:

1. the maximum ATPase rate is low compared to type 1 bres.

2. the maximum shortening velocity is low compared to type 1 bres.

3. the SR pumping capacity is low compared to type 1 bres.

4. none of the other options is correct.

5. the glycolytic capacity is lower than type 1 bres.

Question 40: In all muscles: 1. force is regulated by troponin.

2. myosin is a monomeric protein.

3. force is normally regulated by ATP levels.


5. actin forms a polymer.

Question 41: Myosin:

1. does not need actin to hydrolyse ATP.

2. uses ADP to detach from actin.


4. releases ATP to create a power stroke.

5. cannot bind to actin when ADP is present.

Question 42: Actin:

1. splits ATP to produce force.

2. is a brous protein.


4. laments are longer than myosin laments.

5. laments are attached at M-lines.

Question 43: Cardiac muscle cells: 1. cannot produce force without light chain phosphorylation.

2. are innervated by multiple neurons.

3. use sodium/calcium exchange to regulate resting calcium levels.


5. are mainly glycolytic in metabolism.

Question 44: Smooth muscle:


2. has a limited range of contraction.

3. uses troponin to regulate force production.4. does not use bones to transmit force.

5. is controlled directly by central nervous system nerves.

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CONTINUED

Question 45: The neurotransmitter acetyl choline (ACh):

1. is released by the parasympathetic nervous system.

2. is broken down by ACh reductase.

3. does not activate skeletal muscle.4. increases heart rate.


Question 46: Smooth muscle contraction force:


2. is regulated by myosin light chain kinase.

3. develops faster than type 2 skeletal muscle bres.

4. drops at short sarcomere lengths.

5. is independent of shortening velocity.

Question 47: Smooth muscle cells:

1. dont need high calcium levels to maintain force.


3. dont form motor units.

4. contain multiple nuclei.

5. are found only in hollow organs.

Question 48: Muscle action potentials are always:

1. dependent on sodium inux.

2. faster than in nerves.

3. shorter than the contraction time.


5. generated by nervous system activity.

Question 49: The sarcoplasmic reticulum:

1. is most abundant in type 2 muscle bres.


3. stores ATP for muscle contraction.

4. is not found in all muscle cell types.

5. uses sodium/calcium exchange to transport calcium.

Question 50: Cardiac muscle:

1. can be myogenic.

2. can be myogenic, is striated like skeletal muscle and contracts more

slowly than type 2 skeletal muscle bres.

3. contracts more slowly than type 2 skeletal muscle bres.


5. is not striated like skeletal muscle.

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CONTINUED

SHORT ANSWER QUESTIONS FOLLOW

THERE ARE NO QUESTIONS ON THIS PAGE.

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CONTINUED

THE UNIVERSITY OF AUCKLAND

BIOSCI 107

Short Answer Questions Section

Instructions

Print your name and ID at the top of each answer page.

Record your answers in the spaces provided. Only answers in the specifedareas will be

marked.

All questions should be attempted.

Short Answer Format

Section B: Cell Processes 15 marks

Section C: Blood and Immune Systems 15 marks

Section D: Excitable Tissues: Neurons 10 marks

Section E: Excitable Tissues: Muscle 10 marks

Total: 50 marks. Recommended time: 60 minutes.

CP B&I ET:M ET:N ALL

Admin Use Only

ID NUMBER: ___________________________

SURNAME: ____________________________ FIRST NAME: ______________________

15 15 10 10 50

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CONTINUED

THERE ARE NO QUESTIONS ON THIS PAGE.

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CONTINUED

QUESTION/ANSWER SHEET

ID NUMBER: ___________________________


SECTION B: CELL PROCESSES

15 marks


7Circles for use

of markers

only

51. Please use Figure 2 to answer the following questions.

(a) On the diagram indicate whether the 4 membrane transport proteins shown are

either primary active transporters, secondary active transportersor ion

channels. (2 marks)

(b) Fill in the blanks: (5 marks)

The _____________________________ utilises the Na+gradient to accumulate

Cl-ions against its __________________________ gradient. This gradient is

maintained by the active removal of _____________________ and enhanced by

the recycling of _______________________ to generate a negative membrane

potential. Cl-exit across the apical membrane is the ________________________

in Cl-secretion and is mediated by a channel called ________________________.

To preserve ___________________ Na+ions are pulled across the epithelium to

negate the ___________________ potential established in the lumen of the gland.

The resultant _______________ difference generated across the epithelium

produces a nett water ow that results in a(n) ___________________ secretion.

Please study the following gure.

Figure 2

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CONTINUED

8

51. (c) In the space provided draw and label a simple diagram that explains how cholera

toxin produces secretory diarrhoea. (3 marks)

52. Ion channels and transporters have fundamentally different properties. Complete the tableby inserting yesor noto indicate whether the Na+channel or the facilitated glucose

transporter have the listed properties. The rst row of the table has been completed for

you. (5 marks)

Property Na+Channel Facilitated glucose

transporter

Exhibits specifcity No Yes

Contains ion selectivity lter

Exhibits saturation

Mediates passive diffusion

Forms a water lled pore

Exhibits gating of open

probabilty

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CONTINUED


ID NUMBER: ___________________________


SECTION C: BLOOD AND IMMUNE SYSTEMS

15 marks


10

53. Please study the following diagram.

Figure 3

(a) For each of the circles

numbered from 1 to 9 in

Figure 3, choose the mostappropriate label from the

following list. Please note

that each letter may be used

more than once.

(9 marks)

A. Stimulates

B. Gives rise to

C. Prevents

D. Free antigens directlyactivate

E. Engulfed by

F. Secrete

Answers:

1. ____________

2. ____________

3. ____________

4. ____________

5. ____________

6. ____________

7. ____________

8. ____________

9. ____________

(b) What is an MHC-II molecule? (1 mark)

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CONTINUED

2

1

Cell membrane

CytoplasmNucleus

Chromosomal DNA

Figure 4a Figure 4b Figure 4c

3

5

54. Please study the following diagram. (5 marks)

Figure 4

Figure 4 shows diagrams representing the three stages of the life-cycle of HIV, after the

infection of a T-helper cell.

(a) For Figure4A, what does label 1 point to?

(b) For Figure4A, what does label 2 point to?

(c) BRIEFLY describe in the space below what is happening in Figure4B.

(d) For Figure4C, what is the small circle indicated by label 3?

(e) BRIEFLY describe in the space below what is happening in Figure4C.

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CONTINUED

55. In the boxes below, place the events involved in generating an action potential and

synaptic transmission in a sensory neuronin the order in which they occur:

A. The receptor potential is transmitted passively to the trigger zone of the axon.

B. The action potential arrives at the pre-synaptic terminal of the axon causing

release of the neurotransmitter glutamate. This evokes excitatory postsynaptic

potentials (EPSPs) in the postsynaptic membrane of the receiving neurons.

C. Threshold depolarisation occurs in the trigger zone of the axon and an action

potential is evoked.

D. A stimulus acts on the receptor and causes a local depolarisation of the cellmembrane, known as the receptor potential.

E. The current generated by the action potential in the trigger zone of the axon

spreads passively to the adjacent region of the axon, causing threshold

depolarisation and the generation of a new action potential in that region.

(5 marks total)

Answers:


ID NUMBER: ___________________________


SECTION D: EXCITABLE TISSUES: NEURONS

10 marks


5

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CONTINUED

56. The list 15 shows ve denitions. The list AtoEshows ve terms. Please match thecorrect terms with the correct denition. (5 marks total)

1. The minimum level of

depolarisation required for

an action potential to be

generated.

A. Inhibitory Postsynaptic

Potential (IPSP)

2. A neurotransmitter caused

hyperpolarisation of the

postsynaptic membrane.

B. Relative refractory

period

3. Area where the actionpotentials arise.

C. Absolute refractoryperiod

4. Time during which a neuron

cannot produce an action

potential even with a very

strong stimulus.

D. Threshold

5. Period of time when a second

action potential can be initiated

with a very strong stimulus.

E. Axon hillock

Answers:

1. _____________

2. _____________

3. _____________

4. _____________

5. _____________

5

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10


ID NUMBER: ___________________________


SECTION E: EXCITABLE TISSUES: MUSCLE

10 marks


57. The following summarises events during contraction of the heart. Please insert the

missing word(s) or number(s) to complete the paragraph. (Total 10 marks)

In the heart, the beat is initiated by ________________ cells found in the ____________

node. The rate of discharge of these cells is controlled by the neurotransmitters

______________________ and ______________________. The neurotransmitter

_________________ increases the heart rate which also __________________the

force of cardiac ________________. From there, the action potential passes through

the ______________________ to the __________________ node and then

down the _______________ via the bundle of __________________ to reach the

___________________ bres that cover and enter the __________________. The

______________________ complex of the ECG reects the _________________ of

the ventricular muscle mass and the contraction phase known as_________________

and the peripheral blood pressure _________________. As the ventricular cells

repolarise, the _________________ of the ECG is seen which marks the start of the

_________________ period when the ventricle rells with blood. This is normally

followed by a _________________ marking the start of the next heart beat.

biosci107 2010 exam

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