NSAA 2023 Section 1, Part D (Biology questions)

Ambrosia beetles carry fungal spores from tree to tree. The beetles make holes in the branches of trees and create a network of tunnels in the wood. The fungus grows along the walls of the tunnels providing the only food source for the beetles. The fungus can penetrate xylem vessels and block them, which eventually kills the tree.

Which option correctly describes the relationship between these organisms?

Which of the following graphs could describe processes taking place in the leaf of an oak tree in the presence of light?

Three graphs are shown:
1. rate of photosynthesis against temperature;
2. mass of carbon dioxide used in the leaf against temperature;
3. rate of photosynthesis against time of day (from 0:00 to 24:00) and against distance from a light source.

The diagram shows the flow of energy in a year's growth of grass from $$\begin{gathered} 1 \\ {\mathrm{m}}^2 \end{gathered}$$ of grassland.

- 3000 kJ eaten by the cow
- 3520 kJ eaten by other herbivores
- 14800 kJ to decomposers
- of the energy taken in by the cow: 1860 kJ lost in faeces and urine, 1020 kJ in breath, movement and heat loss, and 120 kJ to growth of the cow

Which of the following statements is/are correct?

1. 62% of the energy consumed by the cow is lost in faeces and urine.
2. The diagram illustrates all the main processes of carbon uptake and release in the carbon cycle.
3. 4% of the energy absorbed by the cells of the cow is used for growth.

A Petri dish was filled with agar that had been mixed with starch. The agar is not digested by the enzymes used in the experiment.

Four small wells were cut in the agar. Three were filled with different solutions. Well Y was filled with water to act as a control.

The dish was kept at $$\begin{gathered} 30{ \\ }^{\circ }\mathrm{C} \end{gathered}$$ for 30 minutes. The surface of the agar was then washed with iodine solution, turning parts of it blue-black in the presence of starch.

The Petri dish was placed on a piece of graph paper to measure the clear areas around the wells. The area of each well should be considered negligible.

Which of the statements is/are correct?

1. The area of starch digested around well W is 4 times the area digested around well X.
2. Amylase could have been used in well W and protease could have been used in well X.
3. The solution put in well Z could have contained boiled enzyme.

The diagram shows a bubble potometer at the start of an experiment. The apparatus has a reservoir of water, a sealed rubber tube with a screw clip, and a horizontal glass tube laid against a ruler marked in cm (0 to 12), with an air bubble in the glass tube.

The glass tube has an internal diameter of 1 mm.

After five minutes, one end of the air bubble had moved to the 4 cm mark on the scale.

Which row is correct?

(Each option gives the name of the process being investigated and an expression for the volume of water taken up, in $\mathrm{m}{\mathrm{m}}^3$.)

A chemical was added to a cell dividing by mitosis. This chemical binds to molecules, preventing the separation of the replicated chromosomes.

Using this information, which of the following effects could this chemical have on this cell division?

1. The four daughter cells contain double the normal number of chromosomes.
2. The gametes contain the haploid number of chromosomes.
3. The cell does not divide and contains the diploid number of replicated chromosomes.

A student viewed a bacterial cell using a microscope. The cell was measured with a microscope ruler on which each division measures $$\begin{gathered} 2.5 \\ \mu \mathrm{m} \end{gathered}$$.

The student made a drawing of this cell. The drawing was 5.0 cm in length and included the structures that the student expected to see.

Which row of the table gives the magnification of the student's drawing and one of the structures that should be included?

(Each option gives the magnification of the drawing and a structure that should be included.)

The table shows details of genetic characteristics of three species of organisms and the genetic crosses carried out with them.$$\begin{array}{ccccc}\text{cross}& \text{organism}& \text{dominant characteristic}& \text{recessive characteristic}& \text{description of parents in cross}\\ & & & & \\ V& \text{cattle}& \text{have horns}& \text{hornless}& \text{heterozygous horned}\times \text{hornless}\\ & & & & \\ W& \text{fruit flies}& \text{grey-bodied}& \text{ebony-bodied}& \text{heterozygous grey-bodied}\times \text{heterozygous grey-bodied}\\ & & & & \\ Y& \text{pea plants}& \text{round seeds}& \text{wrinkled seeds}& \text{wrinkled seeds}\times \text{homozygous round seeds}\\ & & & & \end{array}$$All alleles exhibit simple dominant/recessive relationships.

Which of the following statements is/are correct?

1. If two of the offspring from cross V are bred together, three different crosses could result, with three different probabilities of phenotypes in the next generation: 100% hornless, 50% hornless, or 25% hornless.
2. The genotypes of the offspring with the dominant characteristic from cross W will be identifiable through their phenotypes.
3. A farmer planted seeds collected from the offspring of cross Y. If these seeds grew and produced flowers which were then cross-pollinated with each other, the resulting seeds would yield a crop containing 50% homozygous plants.

The table shows the relationship between heart rate and blood output from the left ventricle of a healthy human heart.$$\begin{array}{ccccccccc}\text{heart rate / beats per minute}& 55& 70& 80& 90& 120& 140& 150& 175\\ & & & & & & & & \\ {\text{blood output each minute / dm}}^3& 4.0& 5.0& 5.2& 5.6& 6.0& 6.0& 5.8& 4.6\\ & & & & & & & & \end{array}$$Which of the following statements is/are correct?

1. The volume of blood pumped out of the heart each minute is directly proportional to the heart rate.
2. When the heart rate increased from 55 to 70 beats per minute, the blood output from the heart increased by 20%.
3. Blood output from the heart to the lungs will be less than that to the rest of the body.

The diagram shows a flow chart representing the hormonal activity associated with the menstrual cycle. In the chart the hypothalamus releases gonadotrophin-releasing hormone (GnRH), which acts on the anterior pituitary; the anterior pituitary releases hormone 1 and hormone 2; the ovarian follicle releases hormone 3 and the ovarian corpus luteum releases hormone 4. A minus sign indicates a negative feedback loop, and a plus sign indicates a loop in which an ovarian hormone stimulates the release of a second hormone from the pituitary gland.

Which of the following statements about the menstrual cycle is/are correct?

1. Hormone 1 stimulates follicle maturation and the release of hormone 3 from the ovarian follicle.
2. Hormone 4 maintains the uterus lining.
3. At the end of the menstrual cycle the levels of hormone 1 and hormone 2 will reach their highest point and then decrease, leading to menstruation.

A scientist investigated the effect of substrate concentration on the activity of the enzyme lipase.

Two test tubes were set up: one containing a sample of full-fat milk mixed with an alkaline solution and a pH indicator, and one containing lipase. The pH indicator turned the alkaline milk sample pink. Both tubes were incubated in a water bath at the optimum temperature for lipase.

The scientist then added the lipase to the tube with the milk and measured the time taken for the indicator to turn colourless. This colour change was caused by an increase in the concentration of one of the products of the reaction.

Further samples of the milk were diluted and added to the same quantity of alkaline solution and pH indicator to produce another six different substrate concentrations, and the experiment was repeated. All other variables were kept constant.

Each substrate concentration caused the pH indicator to change to colourless in a different length of time, and the results were plotted on a graph of the time taken for the pH indicator to change to colourless against substrate concentration.

Which option correctly identifies the shape of the graph of the results, the limiting factor during the experiment and an explanation for the change in colour of the pH indicator?

(Each option gives the shape of the graph, the limiting factor and the reason for the colour change.)

Even when sufficient oxygen is available, yeast will respire anaerobically using glucose as a substrate. However, if its source of glucose runs out and oxygen is available, yeast can switch to using ethanol as a substrate, which it uses to respire aerobically.

A sample of yeast was added to $$\begin{gathered} 100 \\ \mathrm{c}{\mathrm{m}}^3 \end{gathered}$$ of glucose solution in an open flask. The contents were monitored over 32 hours. The graph shows the concentration of glucose, the concentration of ethanol and the concentration of yeast against time.

Which of the following statements are correct?

1. Carbon dioxide would be produced in the flask at all times throughout the observation period, regardless of whether the yeast was respiring aerobically or anaerobically.
2. The yeast was respiring using ethanol as the only substrate for 22 hours.
3. The yeast started respiring anaerobically from the start of the observation period.
4. The yeast used an average of 4 g glucose per hour for the first 10 hours.

The diagram represents part of the carbon cycle. Arrows numbered 1 to 7 connect a pool of carbon in the air, plants, animals, decomposers and fossil fuels.

Which of the arrows represent processes resulting in at least one organic product (a product that contains carbon and hydrogen)?

In an experiment, 8 identical cubes of potato were each weighed and placed in a different test tube. Each tube contained a different concentration of sodium chloride solution. All other conditions were kept the same.

After 30 minutes the potato cubes were removed, weighed, and the percentage change in mass was calculated and plotted against the concentration of sodium chloride. The percentage change in mass is positive at low concentrations and negative at high concentrations, passing through zero at a sodium chloride concentration of about $$\begin{gathered} 0.3 \\ \mathrm{mol} \\ \mathrm{d}{\mathrm{m}}^{-3} \end{gathered}$$.

Which of the following statements is/are correct?

1. The initial concentration of sodium chloride inside the potato cubes must be $$\begin{gathered} 0.3 \\ \mathrm{mol} \\ \mathrm{d}{\mathrm{m}}^{-3} \end{gathered}$$.
2. Osmosis involves the diffusion of water molecules from a solution of high solute concentration to one of low solute concentration.
3. In this experiment, the rate of osmosis is fastest at a sodium chloride concentration of $$\begin{gathered} 0.8 \\ \mathrm{mol} \\ \mathrm{d}{\mathrm{m}}^{-3} \end{gathered}$$.

The same section of a gene was taken from two different people and the DNA sequenced to show the triplets on one strand. The results for each person are shown.$$\begin{array}{cc}\text{person 1}& \text{person 2}\\ & \\ \mathrm{TCC}& \mathrm{TCC}\\ & \\ \mathrm{GCG}& \mathrm{GCG}\\ & \\ \mathrm{AGC}& \mathrm{AGC}\\ & \\ \mathrm{CCC}& \mathrm{CCG}\\ & \\ \mathrm{TTG}& \mathrm{TTA}\\ & \\ \mathrm{AGG}& \mathrm{AGG}\\ & \end{array}$$Which of the following statements about the sequences could be correct?

1. Person 2 has one mutation in the section of the gene.
2. Both people have the same phenotype for this gene.
3. This section of the gene codes for up to 6 bases.

The family tree shows the inheritance of an autosomal recessive genetic condition. The key identifies males without the condition, females without the condition and females with the condition. Four individuals are numbered 1 to 4.

Which of the following statements is/are correct for this family?

1. If one cheek cell is collected from each individual, the overall ratio of X chromosomes to Y chromosomes will be $3.67:1$.
2. The probability of individual 2 and individual 3 having the same alleles on their X chromosomes is 100%.
3. The probability of individual 2 and individual 3 having the same genotype for the condition is 50%.

(Assume no mutations.)

The sugar present in DNA contains 5 carbons.

A section of single-stranded DNA contains five different triplets. Which of the following statements about this strand could be correct?

1. There are 75 carbons in the sugar-phosphate backbone in this section.
2. The minimum number of different bases present in the base sequence is 2.
3. The number of sugar-to-phosphate bonds is equal to the number of nucleotides.

The graph shows the change in the pressure in the space X between the wall of the thorax and the lungs during one complete breathing cycle. An accompanying diagram shows the wall of the thorax, the lung, the diaphragm and the space X between the thorax wall and the lung. The pressure in space X is plotted in arbitrary units against time in seconds, over one cycle lasting 4 seconds.

Which of the following statements is/are correct?

1. The person is breathing out between 0 and 1.5 seconds.
2. The diaphragm is relaxing between 2 and 3 seconds.
3. The rate of breathing is 15 breaths per minute.

(Assume the person continues breathing at the same rate.)

In a mammal, an impulse travels along a neurone of length 45 cm in $3.0\times 10^{-3}$ seconds. Transmission across the synapse to another neurone takes $4.0\times 10^{-10}$ seconds. The synapse has a width of 20 nm.

Which row correctly compares the speed of transmission across the synapse with the speed of transmission along the neurone, and gives the method of transmission across the synapse?

(Each option gives the speed across the synapse compared to the speed along the neurone, and the method of transmission across the synapse.)

Four blood cells were taken from a human:

- one that was about to start cytokinesis
- one actively producing antibodies
- two that cannot use oxygen for respiration

What is the total number of chromosomes present in all of the cells mentioned above?

(Ignore mitochondrial DNA.)