Past exam questions - module 1?

Question 1

The resting membrane potential results from [2 marks]

A uneven distribution of ions across the cell membrane only
B differences in membrane permeability to ions only
C rapid removal of neurotransmitters from the synaptic cleft
D uneven distribution of ions across the cell membrane and differences in membrane
permeability to ions
E activity of the sodium/potassium pump only

Question 2

Which of the following statements about cell-to-cell communication is CORRECT?
[2 marks]

A Paracrine signalling is utilised for long distance signalling
B Reception is the process of a signalling molecule binding to a specific receptor
C Hydrophilic signalling molecules act on receptors located inside cells
D Synaptic signalling is slow
E A hormone is defined as a signalling molecule that is released from a neuron

Question 3

Which of the following statements is an INCORRECT description of changes in membrane
potential? [2 marks]

A Depolarisation makes the membrane potential less negative
B Depolarisation is caused by the flow of sodium ions out of the neuron
C Hyperpolarisation is caused by the flow of potassium ions out of the neuron
D Depolarisation is caused by the flow of sodium ions into the neuron
E Hyperpolarisation makes the membrane potential more negative

Question 4

Establishing the resting membrane potential depends on all of the
following EXCEPT

the closing of most Na+ and Cl-
channels in the cell membrane
movement of K+ ions out of the cell via constitutively open K+
channels

delayed opening of voltage-gated K+ channels to allow
movement of K+ ions out of the cell

establishing a balance between the electrical and chemical
gradients across the cell membrane

activation of the electrogenic pump, Na+/K+-ATPase

Question 5

Which of the following organelles is NOT found in plant cells? [2 marks]
A nucleus
B peroxisome
C centriole
D Golgi apparatus
E smooth endoplasmic reticulum

Question 6

In a eukaryotic cell, the ribosome is responsible for [2 marks]

A synthesising RNA
B storing cell wastes
C detecting invading (foreign) DNA sequences
D generating energy
E protein synthesis

Question 7

A scientist dissolves 15 g of cactose in 500 mL of water. Cactose has a molar mass of 80 g/mole.
What is the molarity of the cactose solution? [2 marks]
A 0.375 moles
B 0.1875 M
C 0.375 M
D 0.215 moles
E 2.67 M

Question 8

In a eukaryotic cell, the process of translation can directly produce [2 marks]

A DNA
B mRNA
C fats
D peptidoglycan
E protein

Question 9

A urine sample has a pH of 6.0. Which of the following statements about the sample is
CORRECT? [2 marks]

A This sample contains no water molecules
B This sample contains more hydroxyl ions than hydronium ions
C This sample contains 1.0 x 10-6 mol/L hydronium ions
D This sample has the same pH as human saliva
E This sample contains 1.0 x 106 mol/L hydronium ions

Question 10

In a covalent bond [2 marks]

A both bonding partners share electrons
B one bonding partner donates an electron
C one bonding partner contributes all of the electrons
D one bonding partner always has more electrons than the other partner
E both bonding partner atoms share the electrons equally

Question 11

During replication of DNA, the DNA strands are separated by [2 marks]

A primase
B helicase
C topoisomerase
D DNA polymerase
E single-stranded DNA binding protein

Question 12

How many ATP molecules are required to ‘activate’ glucose during the first, ‘energy
investment’ phase of glycolysis? [2 marks]

A none
B one
C two
D three
E six

Question 13

Which of the following is NOT found in a DNA molecule? [2 marks]

A adenine
B uracil
C guanine
D phosphate
E deoxyribose

Question 14

The transport of molecules across the plasma membrane against a concentration gradient (i.e.
from low to high concentration) [2 marks]

A generates energy in the form of ATP
B is mediated by facilitated diffusion
C is required for protein synthesis
D depends on the presence of cholesterol
E requires active transport and consumes energy

Question 15

Co-transport of glucose and Na+
ions occurs across intestinal epithelial cells. Which of the
following statements about this process in the intestinal cells is CORRECT? [2 marks]

A Glucose cannot accumulate against its concentration gradient
B Glucose transport using the co-transporter can occur even if Na+
ions are not present
C Na+
/K+
-ATPase coupled to the co-transporter can indirectly drive active transport of
glucose
D The co-transporter can only move Na+
ions against their concentration gradient
E Energy from GTP is required for the transport of glucose and Na+
ions

Question 16

Establishing the resting membrane potential depends on all of the following EXCEPT
[2 marks]

A delayed opening of voltage-gated K+
channels to allow movement of K+
ions out of the
cell
B movement of K+
ions out of the cell via constitutively open K+
channels
C most Na+
and Clchannels in the cell membrane being closed
D establishing a balance between the electrical and chemical gradients across the cell
membrane
E activation of the electrogenic pump, Na+
/K+
-ATPase

Question 17

An action potential normally only moves in one direction along the axon, because
[2 marks]

A there are no conditions under which an action potential can be generated in both directions
in an axon

B Na+
/K+
-ATPase quickly restores the resting membrane potential

C voltage-gated Na+
channels ‘behind’ the site of depolarisation are inactivated and cannot
open in response to depolarisation

D voltage-gated Na+
channels ‘behind’ the site of depolarisation are open
E Na+
ions rush into the cell

Question 18

You wish to prepare 16 mL of 150 mM MgCl2 solution using a 2.0 M stock solution. Which of
the following are the correct volumes of solutions you will mix together? [2 marks]
A 1.6 mL of distilled water and 14.4 mL of stock
B 1.2 mL of stock and 14.8 mL of distilled water
C 8 mL of stock and 8 mL of distilled water
D 12.9 mL of distilled water and 3.1 mL of stock
E 2.0 mL of stock and 16 mL of distilled water

Question 19

When red blood cells of a sheep are placed in a 200 mOsmol/L solution of glucose, which of
the following statements regarding extracellular fluid (ECF) CORRECTLY describes what will
happen? [2 marks]
A There will be a net movement of water out of cells and into the ECF where there is a
lower concentration of solutes
B There will be a net movement of water out of cells and into the ECF because the glucose
solution is hypertonic relative to the contents of the red blood cells
C There will be a net movement of water from the ECF into the cells where there is a higher
concentration of solutes
D There will be no net movement of water
E There will be a net movement of water from the ECF into the cells where there is a higher
concentration of water

Question 20

During DNA replication, you observe that the Okazaki fragments are not joined, and the RNA
primers on the lagging strand are not being replaced by DNA?

Which TWO (2) DNA replication enzymes do you think are NOT functioning correctly?

Justify your answer for EACH ONE with a brief explanation of what the protein does, and why
a mutation in this protein would contribute to the effect described above. [2.5 marks for each
protein]

Please choose your two proteins from this list:

DNA polymerase I Okazakase
DNA polymerase III primase
DNA ligase single-stranded binding protein
exogenase topoisomerase
helicase

[5 marks]

Question 21

Here is a DNA molecule:
5’ P GGTAGCTTT 3’
3’ CCATCGAAA 5’

The promoter and the direction of transcription are indicated by the letter P and the arrow.

Assuming that the RNA produced from the DNA is translated from the beginning, what is the
sequence of the protein product? [5 marks]
[58839]

Show your working for your answer (including the mRNA sequence that will be translated).
The Genetic Code table is shown below for your use.

Question 22

Which of the following is a CORRECT sequence of levels in life’s hierarchy, proceeding
upward from a cell? [2 marks]

A tissue, ecosystem, atom
B organism, organs, tissues
C organelle, molecule, atom
D tissue, organ, organism
E organ, ecosystem, tissue

Question 23

In a eukaryotic cell, the chloroplast is responsible for [2 marks]

A detecting invading (foreign) DNA sequences
B synthesising hormones
C capturing the energy in sunlight
D synthesising RNA
E storing cell wastes

Question 24

A scientist dissolves 28 g of cactose in 500 mL of water. Cactose has a molar mass of 130
g/mole. How many moles of cactose are in the solution? [2 marks]

A 4.64 moles
B 0.215 M
C 0.215 moles
D 0.43 moles
E 0.43 M

Question 25

In a eukaryotic cell, the process of transcription can directly produce [2 marks]

A DNA
B tRNA
C protein
D peptidoglycan
E fats

Question 26

During replication of DNA, the single-stranded DNA is protected by [2 marks]

A primase
B single-stranded DNA binding protein
C topoisomerase
D helicase
E DNA polymerase

Question 27

How many pyruvate molecules are produced per glucose during the glycolysis step in cellular
respiration? [2 marks]

A none
B one
C two
D three
E six

Question 28

The side chain of an amino acid can NOT be [2 marks]

A hydrophilic
B aliphatic
C aromatic
D hydrophobic
E a nitrogenous base