Mock Exam Set 1 - Paper 1

The giant algae Acetabularia can be a model organism for studying the biology of a plant cell. Which characteristics of Acetabularia make it a good model organism?

• A.$\hspace{1em}$ Both, Acetabularia cells and plant cells, do not have a cell wall.

• B.$\hspace{1em}$ Acetabularia is composed of one large cell.

• C.$\hspace{1em}$ Acetabularia is composed of many large cells.

• D.$\hspace{1em}$ Acetabularia contains a pigment which makes its structures easily visualised.

The important properties of animal cell membranes are fluidity and permeability. Which molecule is responsible for ensuring the membrane’s fluidity?

• A.$\hspace{1em}$ Cholesterol

• B.$\hspace{1em}$ Integral Membrane Proteins

• C.$\hspace{1em}$ Glycolipids

• D.$\hspace{1em}$ Peripheral Membrane Proteins

When is the concentration of cyclin E the highest during the cell cycle ?

Which of the structures A-D represents the -R group in the molecule below?

$\hspace{1.5em}$A.			B.
$\hspace{1.5em}$C.			D.

Which of the following statements about lipids is true?

• A.$\hspace{1em}$ It is advisable to add trans fats to one’s diet.

• B.$\hspace{1em}$ There is a carbon-carbon triple bond in monounsaturated fats.

• C.$\hspace{1em}$ Polyunsaturated fats are made up of carbon-carbon single bonds to keep them in a liquid state.

• D.$\hspace{1em}$ Saturated fats are made up of carbon-carbon single bonds.

What is the substrate for the enzyme lactase?

• A.$\hspace{1em}$ Glucose

• B.$\hspace{1em}$ Galactose

• C.$\hspace{1em}$ Lactose

• D.$\hspace{1em}$ Fructose

Which substance would need the greatest amount of energy to raise its temperature?

• A. $\hspace{1em}$ Air
• B. $\hspace{1em}$ Methanol
• C. $\hspace{1em}$ Water
• D. $\hspace{1em}$ Coconut oil

Which of the following statements is false regarding translation?

• A.$\hspace{1em}$ Translation needs mRNA, which carries genetic information in the form of codons.

• B.$\hspace{1em}$ The process of translation starts with the start codon AUG.

• C.$\hspace{1em}$ Translation takes place in the nucleus.

• D.$\hspace{1em}$ tRNAs contain anticodons which are complementary to the mRNA’s codons.

The graph shows the amount of oxygen inside a chamber containing yeast cells and substrates as measured by an oxygen sensor. The experimental investigation compared the rate of oxygen consumption during aerobic respiration by the yeast cells using three different substrates: sucrose, fructose and glucose.

What can be concluded from the graph?

• A.$\hspace{1em}$ The hydrolysis of sucrose forms glucose and fructose

• B.$\hspace{1em}$ The breakdown of glucose and fructose is much slower than sucrose

• C.$\hspace{1em}$ The rate of cellular respiration decreases the more complex the substrate

• D.$\hspace{1em}$ The cumulative amount of oxygen consumed by the yeast cells increases over time

The image shows an abnormal human karyotype.

What is the abnormality in this karyotype and its cause?

A biological male with haemophilia and a biological female without haemophilia have a daughter without haemophilia. What are the possible genotypes of the daughter?

• I.	XHXH
  II.	XHXh
  III.	XhXh

• A.$\hspace{1em}$ I only

• B.$\hspace{1em}$ II only

• C.$\hspace{1em}$ II and III only

• D.$\hspace{1em}$ I, II and III

The diagram shows a DNA profile of a child and the profiles of three potential pairs of parents. Which pair(s) could be the actual parents of the child?

• A.$\hspace{1em}$ Parents X only

• B.$\hspace{1em}$ Parents Y only

• C.$\hspace{1em}$ Parents Y and Z only

• D.$\hspace{1em}$ Parents X and Z only

The micrographs show four phases of meiosis I in a plant. In what order do these phases occur?

• A.$\hspace{1em}$ X-Y-W-Z

• B.$\hspace{1em}$ W-Z-X-Y

• C.$\hspace{1em}$ Y-X-W-Z

• D.$\hspace{1em}$ Z-W-X-Y

Chytrids are unicellular organisms that feed on pollen through extracellular secretion of digestive enzymes and absorption of the breakdown products. Which statement describes the nutritional mode of this organism?

• A.$\hspace{1em}$ Autotrophic producer

• B.$\hspace{1em}$ Autotrophic consumer

• C.$\hspace{1em}$ Heterotrophic detritivore

• D.$\hspace{1em}$ Heterotrophic saprotroph

The illustration shows a rice cultivation system that eliminates the need for fertilizers, herbicides and pesticides by raising ducks in rice paddies. Additionally, Azolla, an aquatic floating fern, is grown in these fields because they harbour blue-green algae that fixes N$_2$. This system produces duck, fish and rice for human consumption.

What would be a possible food chain for the rice cultivation system shown in the image?

• A. $\hspace{1em}$ algae $\rightarrow$ fish $\rightarrow$ duck $\rightarrow$ human

• B. $\hspace{1em}$ algae $\leftarrow$ fish $\leftarrow$ duck $\leftarrow$ human

• C. $\hspace{1em}$ insects $\rightarrow$ algae $\rightarrow$ duck $\rightarrow$ human

• D. $\hspace{1em}$ insects $\leftarrow$ algae $\leftarrow$ duck $\leftarrow$ human

Which process is most likely responsible for the origin of mitochondria as a eukaryotic cell organelle?

• A.$\hspace{1em}$ Osmosis

• B.$\hspace{1em}$ Exocytosis

• C.$\hspace{1em}$ Apoptosis

• D.$\hspace{1em}$ Endocytosis

Which characteristics of carbon dioxide make it a greenhouse gas of concern?

• A.$\hspace{1em}$ Absorbs long wave radiation and has a significant concentration in the atmosphere.

• B.$\hspace{1em}$ Emits shortwave radiation and has a significant concentration in the atmosphere.

• C.$\hspace{1em}$ Absorbs shortwave radiation and has a high stability.

• D.$\hspace{1em}$ Blocks infrared radiation and has a high stability.

A population of plants with no resistance to herbivores may develop into a population of plants that secrete a compound toxic to herbivores. How could this change occur?

• A.$\hspace{1em}$ The gene for the toxic compound was inherited from an ancestor of the plant population.

• B.$\hspace{1em}$ A mutation during DNA replication, prior to meiosis, resulted in a DNA sequence that codes for the compound.

• C.$\hspace{1em}$ The enzyme needed to produce the compound was transferred by a plant from another population.

• D.$\hspace{1em}$ Individuals in the plant population mutated in response to the pressure from herbivores.

The phylogenetic tree below shows relationships among species in four phyla of land plants.

The divisions of land plants have important differences. Which of these phyla produce seeds?

• A.$\hspace{1em}$ Angiospermophyta only

• B.$\hspace{1em}$ Coniferophyta and angiospermophyta

• C.$\hspace{1em}$ Bryophyta only

• D.$\hspace{1em}$ Bryophyta and filicinophyta

What helps prevent the backflow of blood in a vein?

• A.$\hspace{1em}$ Relaxation of skeletal muscles

• B.$\hspace{1em}$ Venous valves

• C.$\hspace{1em}$ Relaxation of the heart

• D.$\hspace{1em}$ Thin vessel walls

Which of the following is associated with non-specific immunity?

• A. $\hspace{1em}$ Lymphocytes

• B. $\hspace{1em}$ Antibodies

• C. $\hspace{1em}$ Memory cells

• D. $\hspace{1em}$ Mucus

Which row in the table below correctly outlines the sequence of events for the digestion and absorption of starch products?

Which of the following is not an example of speciation?

• A. $\hspace{1em}$ Evolution of different beak shapes in finches (C. olivacea)

• B. $\hspace{1em}$ Breeding varieties of green apples (M. domestica) with desirable characteristics

• C. $\hspace{1em}$ Squirrels on the North and South rims of the grand canyon, who cannot interbreed

• D. $\hspace{1em}$ Buffalo grass (B. dactyloides) is able to grow in polluted soil but other species of grass cannot

The diagram shows a process that occurs in the membranes of neurons during a stage of the action potential. What process does the diagram depict?

• A.$\hspace{1em}$ Open sodium channels initiating depolarisation.

• B.$\hspace{1em}$ The sodium/potassium pump initiating depolarisation.

• C.$\hspace{1em}$ Open sodium channels restoring the resting potential.

• D.$\hspace{1em}$ The sodium/potassium pump restoring the resting potential.

The diagram shows a frontal view of the female reproductive organs.

What structures are labeled by the numbers 1, 2, and 3?

Hershey and Chase conducted experiments using the radioactive isotopes ³⁵S and ³²P which demonstrated that DNA is the genetic material. What would they have observed about the distribution of isotopes in the centrifuged sample if protein, rather than DNA, were the genetic material?

• A.$\hspace{1em}$ High proportion of ³⁵S in the bacterial pellet relative to the supernatant.

• B.$\hspace{1em}$ High proportion of ³²P in the bacterial pellet relative to the supernatant.

• C.$\hspace{1em}$ High proportion of both ³⁵S and ³²P in the bacterial pellet relative to the supernatant.

• D.$\hspace{1em}$ Low proportion of both ³⁵S and ³²P in the bacterial pellet relative to the supernatant.

Why can a eukaryote produce a larger number of mRNA transcripts than the number of genes in its genome?

• A.$\hspace{1em}$ Some mRNA transcripts are double-stranded.

• B.$\hspace{1em}$ There are genes that produce multiple different mRNA transcripts.

• C.$\hspace{1em}$ Not all mRNA transcripts are produced by genes.

• D.$\hspace{1em}$ Some mRNA transcripts are produced by other mRNA transcripts.

Which characteristics distinguish between an alpha helix and a beta-pleated sheet?

• I.	The positions of hydrogen bonds between different amino acids
  II.	The location of hydrophobic interactions between nonpolar R groups
  III.	The positions of disulfide bridges between cysteine residues

• A.$\hspace{1em}$ I only

• B.$\hspace{1em}$ I and II only

• C.$\hspace{1em}$ II and III only

• D.$\hspace{1em}$ I, II, and III

The diagram shows the pathway that converts threonine to isoleucine.

What is the name and mechanism of the process through which isoleucine interacts with threonine dehydratase?

A mitochondrion is shown in the diagram. Which letter indicates the site where protons accumulate prior to the formation of ATP?

In which structure of the chloroplast does ribulose bisphosphate undergo carboxylation?

• A.$\hspace{1em}$ Thylakoid space

• B.$\hspace{1em}$ Stroma

• C.$\hspace{1em}$ Thylakoid membrane

• D.$\hspace{1em}$ Chloroplast membrane

The graph shows the results of an experiment which used radioactively labelled carbon dioxide (¹⁴CO$_2$) to investigate the time taken for sap to travel to different colonies of aphids present on a plant.

Which conclusion could be supported by these results?

• A.$\hspace{1em}$ All colonies received an equal amount of sap.

• B.$\hspace{1em}$ All colonies were equally spaced along the stem of the plant.

• C.$\hspace{1em}$ Colony 1 fed on the sap more quickly than other colonies.

• D.$\hspace{1em}$ Colony 1 was located closest to the leaves.

Plant shoots detect and respond to light. What plant protein detects light, and what mechanism initiates the response?

What causes flowering?

• A. $\hspace{1em}$ Differentiation in the lateral meristem

• B. $\hspace{1em}$ Changes in gene expression in the apical meristem

• C. $\hspace{1em}$ Stimulation of phototropins

• D. $\hspace{1em}$ Gene mutation in the apical meristem

The diagram shows gametes produced from two homologous chromosomes.

What single crossover event could have occurred to produce the gametes?

• I.	Crossover between Gene A and B
  II.	Crossover between Gene B and C
  III.	Crossover between Gene C and D

• A.$\hspace{1em}$ I only

• B.$\hspace{1em}$ II only

• C.$\hspace{1em}$ I and II only

• D.$\hspace{1em}$ II and III only

A dihybrid cross was carried out between two sunflower plants (Helianthus annuus) to see if the genes for seed number and seed shape are linked. The critical value for the chi-squared test at the 0.05 significance level was 7.82. The calculated value for the chi-squared test was 10.05; what does this indicate?

• A. $\hspace{1em}$ The null hypothesis can be rejected and the genes are linked

• B. $\hspace{1em}$ The null hypothesis can be accepted and the genes are unlinked

• C. $\hspace{1em}$ The alternative hypothesis can be rejected and the genes are linked

• D. $\hspace{1em}$ The alternative hypothesis can be accepted and the genes are unlinked

In blood donation, an acute hemolytic transfusion reaction occurs when red blood cells are attacked by the recipient’s immune system. Which property of red blood cells explains this response?

• A.$\hspace{1em}$ B cells recognize all red blood cells as foreign.

• B.$\hspace{1em}$ Foreign red blood cells have surface antibodies that interact with T cells.

• C.$\hspace{1em}$ Foreign red blood cells have surface antigens that stimulate antibody production.

• D.$\hspace{1em}$ Antibodies are unable to bind to foreign red blood cells.

Which statement(s) are true for ATP hydrolysis during muscle contraction?

• I.	ATP is hydrolysed by the sarcoplasmic reticulum
  II.	ATP hydrolysis causes myosin heads to move into the ready position
  III.	ATP hydrolysis causes the cross-bridges to break

• A.$\hspace{1em}$ I, II and III

• B.$\hspace{1em}$ I only

• C.$\hspace{1em}$ II only

• D.$\hspace{1em}$ III only

Which letter indicates the part of the nephron that is impermeable to salts and plays a role in increasing filtrate solute concentration to 200 - 300% relative to normal blood solute concentration?

Which hormone is released by an embryo early in pregnancy in order to stimulate the ovary to secrete progesterone?

• A.$\hspace{1em}$ LH

• B.$\hspace{1em}$ Estrogen

• C.$\hspace{1em}$ hCG

• D.$\hspace{1em}$ FSH