OCR A Level Biology B (Advancing) Fundamentals of biology June 2018 question paper H422/01

Which of the rows, A to D, from the table below indicates the type of bond present (✓) or absent (8 in the secondary structure of a protein?

A student is purifying DNA from a bacterial culture.

Which of the molecules, A to D, is required for the precipitation of DNA during the purification process?

A ethanol

B glucose

C lysozyme

D water

Which of the statements, A to D, is true of single nucleotide polymorphisms (SNPs)?

A All SNPs have four possible variations.

B Genetic recombination can generate a SNP.

C SNPs can influence banding patterns on a DNA fingerprint.

D SNPs occur in exons only.

The image below is a photomicrograph of a human blood smear. Three cells are labelled X, Y and

Questions 4 and 5 refer to this image.

The diameter of cell X in the image is 15.5 mm and its actual diameter is 12.4 m.

Which of the options, A to D, is the magnification of the image?

A ×125

B ×800

C ×1250

D ×8000

Which of the rows, A to D, in the table below correctly identifies cells X, Y and Z ?

Meiosis II pauses in the secondary oocyte and is only completed if fertilisation occurs.

Which of the options, A to D, is a description of the last meiotic stage prior to fertilisation?

A Homologous chromosomes align to the equator of the oocyte.

B Homologous chromosomes migrate to opposite poles of the oocyte.

C Single chromosomes align to the equator of the oocyte.

D Sister chromatids migrate to opposite poles of the oocyte.

Which of the options, A to D, is an action of luteinising hormone (LH) in males?

A inhibition of follicle-stimulating hormone (FSH) release

B initiation of spermatogenesis

C sensitisation of testicular cells to testosterone

D stimulation of testosterone release

Antidiuretic hormone (ADH) is required for osmoregulation.

Which of the options, A to D, is a region of the nephron that is responsive to ADH?

A Bowman’s capsule

B collecting duct

C loop of Henle

D proximal convoluted tubule

Which of the options, A to D, is the heart chamber in which electrical activity is initiated?

A left atrium

B left ventricle

C right atrium

D right ventricle

A doctor takes a blood pressure measurement from a patient using a manual sphygmomanometer.

Here are three statements about the doctor’s examination:

1 The patient has hypertension that requires medical treatment.

2 The greatest pressure exerted on the patient’s arterial walls during the cardiac cycle is 260 mm Hg.

3 At cuff pressures below 100 mm Hg, blood flow can be heard using a stethoscope.

Which of the statements is/are correct?

A 1, 2 and 3 are correct

B Only 1 and 2 are correct

C Only 2 and 3 are correct

D Only 1 is correct

Which of the options, A to D, is the long-term effect of aerobic training on VO₂ max and excess post-exercise oxygen consumption (EPOC)?

A decreased VO₂ max and decreased EPOC

B decreased VO₂ max and increased EPOC

C increased VO₂ max and decreased EPOC

D increased VO₂ max and increased EPOC

The diagram below represents the ultrastructure of a single sarcomere in skeletal muscle.

Three features of the sarcomere are labelled P, Q and R.

Here are three statements about the diagram:

1 During muscle contraction, R slides along P.

2 P is responsive to calcium ions.

3 Q is responsive to ATP molecules.

Which of the statements is/are correct?

A 1, 2 and 3 are correct

B Only 1 and 2 are correct

C Only 2 and 3 are correct

D Only 1 is correct

Excitatory and inhibitory postsynaptic potentials have similarities and differences.

Which of the options, A to D, is a feature of an excitatory, but not inhibitory, postsynaptic potential?

A all-or-nothing response

B depolarising

C graded in response

D hyperpolarising

Which of the options, A to D, is a molecule that requires vitamin C for its synthesis?

A collagen

B deoxyribonucleic acid

C haemoglobin

D rhodopsin

Which of the options, A to D, is true of type 2 diabetes?

A caused by autoimmunity

B present from birth

C rapid onset

D slow onset

Glaucoma is an eye condition caused by increased pressure within the eye.

Which of the options, A to D, is a correct explanation for the increased pressure?

A decreased production of aqueous humour

B increased production of vitreous humour

C poor drainage of aqueous humour

D poor drainage of vitreous humour

15 cases of thyroid cancer were recorded in Iceland between December 2009 and January 2011.

The graph below shows, for each case, the month of diagnosis (▲) and month of recovery (▼) or death (X) from the disease.

Iceland has a population of 330 000 people.

Which of the options, A to D, was the incidence rate (per 100 000) of thyroid cancer in 2010?

A 2.1

B 2.7

C 3.3

D 4.2

Scientists are producing a vaccine against a disease-causing bacterium.

The table below shows the locations and mutation rates of four proteins, A to D, in the bacterium.

Which of the proteins, A to D, is most suitable as the basis of a vaccine against this bacterium?

Which of the options, A to D, describes the type of gene mutation that causes Huntington’s disease?

A change of nucleotide that affects the protein

B change of nucleotide that does not affect the protein

C deletion of nucleotides

D insertion of nucleotides

Here are three statements about the BRCA1 gene:

1 Women with mutations in BRCA1 are at increased risk of breast cancer.

2 BRCA1 mutations can be inherited by males.

3 BRCA1 is a proto-oncogene.

Which of the statements is/are correct?

A 1, 2 and 3 are correct

B Only 1 and 2 are correct

C Only 2 and 3 are correct

D Only 1 is correct

Which of the statements, A to D, is true of epigenetics?

A Guanine is the most commonly methylated DNA base.

B Identical twins show identical epigenetics.

C Proteins cannot undergo epigenetic modification.

D Some epigenetic changes can be reversed.

The polymerase chain reaction (PCR) involves a repeating sequence of temperature changes.

Which of the options, A to D, occurs at a temperature of 72 °C?

A annealing of primers

B detachment of primers

C polymerisation of free nucleotides

D separation of DNA strands

Here are three statements about the evolution of language:

1 Sequencing the genome of extinct human ancestors helps to indicate the origins of language.

2 The evolution of language will have been influenced by reproductive (mating) preferences.

3 The ‘gossip’ hypothesis relies on trust between animals for the acceptance of unfamiliar sounds.

Which of the statements is/are correct?

A 1, 2 and 3 are correct

B Only 1 and 2 are correct

C Only 2 and 3 are correct

D Only 1 is correct

The genetic diversity of monkey populations in a forest ecosystem was studied. The data for one population are shown in the table below.

Which of the options, A to D, is the proportion of polymorphic genes in the monkey population?

A 0.11

B 0.33

C 0.67

D 0.78

Wind speed influences the rate of transpiration in a plant.

Which of the options, A to D, would increase in windy conditions?

A kinetic energy of water molecules in leaf airspaces

B probability that stomata are open

C relative humidity of the atmosphere

D water potential gradient between airspaces in the leaf and the atmosphere

Which of the options, A to D, would promote flowering in a short-day plant?

A longer exposure to cold temperatures

B longer exposure to darkness

C shorter exposure to cold temperatures

D shorter exposure to darkness

A study was conducted to compare the effectiveness of two fertilisers, TomatoXL ® and TomatoGro 27 on the growth of tomato plants.

Twenty plants of similar height were divided randomly into two groups of ten. Each day, one group was fed with TomatoXL ® and the other group with TomatoGro ®.

After one month, the height of each tomato plant was measured and the results were analysed.

Which of the options, A to D, would be the appropriate statistical method to determine which fertiliser was the more effective?

A Chi squared test

B paired Student’s t-test

C Spearman’s rank correlation coefficient

D unpaired Student’s t-test

Which of the molecules, A to D, is the source of electrons in photosynthesis?

A ATP

B CO₂

C H₂O

D NADPH

DCPIP is a molecule that is used to measure the rate of the Hill reaction in isolated chloroplasts.

Which of the options, A to D, correctly describes DCPIP during the Hill reaction?

A it becomes oxidised

B it loses electrons

C it mimics NADP

D it turns from colourless to blue

Proton pumps establish electrochemical gradients, which are required for ATP production.

Which of the options, A to D, are regions of a plant cell into which protons are pumped?

A chloroplast stroma and mitochondrial intermembrane space

B chloroplast stroma and mitochondrial matrix

C thylakoid space and mitochondrial intermembrane space

D thylakoid space and mitochondrial matrix

A Robertsonian translocation is a type of chromosomal translocation in which the long arms of two chromosomes fuse together.

Fig. 31.1 shows this event occurring between chromosomes 14 and 21.

An individual who inherits the translocated chromosome in Fig. 31.1 will either have Down’s syndrome or be a carrier of the disorder.

A couple have a child. The mother is a carrier and the father is genetically normal. The genetic material with respect to chromosomes 14 and 21 in the somatic cells of the parents are shown in Fig. 31.2.

With reference to Fig. 31.2, suggest why the mother does not have Down’s syndrome.

The child is born with Down’s syndrome.

Complete the diagram in Fig. 31.2 to show the genetic material with respect to chromosomes 14 and 21 in:

• the somatic cell of the father

• the gametes of the mother and father

• the zygote of the child.

[Answer on Fig. 31.2]

Down’s syndrome is more commonly caused by a genetic event that is distinct from that shown in Fig. 31.1.

State the name of this event and outline how it arises.

A sample of cells can be collected from a fetus to test for genetic disorders such as cystic fibrosis.

Chorionic villus sampling (CVS) and amniocentesis are two methods of obtaining fetal cells.

State the source of fetal cells that are obtained through these methods.

The sample of fetal cells can be used to produce a karyotype for genetic analysis.

Explain why karyotyping can not be used to detect cystic fibrosis.

Homeostatic mechanisms require hormones, such as thyroxine, to maintain a stable internal environment.

Iodine is required to produce thyroxine.

Explain why a deficiency in iodine could cause weight gain.

The release of thyroxine is regulated by negative feedback and involves two other hormones, as shown in Fig. 32.

Identify hormones X and Y.

Describe the general features of a negative feedback mechanism.

Core body temperature is maintained between 36.5 °C and 37.5 °C.

Describe and explain two physiological mechanisms that would be initiated following a decrease in core body temperature.

Doctors often take temperature measurements from the skin surface, inside the ear or inside the mouth.

Suggest why the ear provides a more accurate measurement of body temperature than the skin surface.

Question 33 begins on page 20

Complete the paragraph below about ecosystems using the most appropriate terms.

Natural change in the community of an ecosystem over time is known as succession.

In this process, biodiversity increases until a …………………………… community is

reached. Human activities such as agriculture and forestry can prevent formation of this

type of community, instead forming a ……………………………. This process is known as

Pioneer species are the first to colonise an ecosystem.

How do pioneer species promote future biodiversity?

Fig. 33 shows a region of coastal land, stretching from tide to woodland.

Outline a sampling method that could be used to investigate succession in this region.

Beef cattle that are produced for their meat are fed maize. In a cow, 13 100 MJ of stored biomass energy are produced from 83 000 MJ of maize.

Calculate the efficiency of this energy transfer in the cow.

In snail farming, snails are fed lettuce leaves.

The efficiency of energy transfer from the lettuce leaves to stored biomass energy in snails is greater than that from maize to stored biomass energy in cattle. Suggest why.

* Cattle are ruminant animals. The stomach of a ruminant animal contains specialised chambers.

Explain how the ruminant stomach digests food to produce important molecules.

Your answer should refer to named chambers of the stomach.

Aerobic respiration involves a series of reactions.

The table below gives three types of reaction involved in aerobic respiration.

Complete the table by inserting, for each type of reaction:

• one metabolic pathway in which the reaction occurs

• the precise location of the metabolic pathway in the cell.

For example, dehydrogenation is a reaction of the Krebs cycle, which occurs in the mitochondrial matrix. The first row has been done for you.

The unbalanced equation for the aerobic respiration of a substrate is shown below.

Balance the equation above by writing the correct numbers in the blank spaces.

Calculate the respiratory quotient (RQ) of this respiratory substrate. Give your answer to two significant figures.

Suggest one reason for an RQ greater than 1 in an organism respiring aerobically.

* A respirometer is used to investigate the rate of respiration.

Fig. 34 shows the setup of a respirometer with two chambers.

Discuss how the respirometer in Fig. 34 can be used to calculate the RQ of germinating peas.

This question is about the development of medicines.

What are the features of a chronic disease?

Over half of commonly-used drugs are similar or identical to chemicals found in plants.

Name one such drug and state its medical use.

Drugs must be evaluated for safety and effectiveness in clinical trials before they are licensed for the treatment of specific diseases.

A clinical trial was conducted to investigate the effect of a drug on blood glucose levels in patients with type 2 diabetes. Blood glucose levels can be monitored by measuring glycosylated (or glycated) haemoglobin (HbA_1C).

• Sixty patients with untreated type 2 diabetes were recruited.

• HbA_1C levels were measured before the trial began.

• The patients were divided into two groups.

• One group received daily drug treatment and the other group received a daily placebo.

• After three months, HbA_1C levels were measured and changes from pre-trial measurements were calculated.

Fig. 35 shows the results of the trial. The boxes show the mean change in HbA_1C levels after three months and the error bars represent standard deviations.

State the phase of the clinical trial in which the data in Fig. 35 were obtained.

Describe what a placebo is and explain why it was used.

Compare the results shown in Fig. 35 for the group receiving the placebo with the group receiving the drug.

Suggest two reasons why this trial does not support the use of the drug in the treatment of type 2 diabetes.

Water is a polar molecule. Molecules of water are attracted to each other.

Fig. 36.1 shows the structure of a water molecule.

Fig. 36.1

Draw a second water molecule on Fig. 36.1, in the position it might take up beside the first water molecule.

Your drawing should show:

• the bond(s) between the two molecules

• the name of each bond

• the charges on each atom.

[Answer on Fig. 36.1]

Water is required for many metabolic reactions, such as the hydrolysis of starch.

The enzyme that catalyses this reaction, amylase, is commonly used in the food industry. It is produced in large-scale bacterial cultures.

A group of students investigated the amylase activity of five bacterial species.

The bacterial species were treated using the following method:

1. Prepare three nutrient agar plates containing 1% potato starch.

2. Soak five paper discs with cultures of five bacterial species, A to E.

3. Allow excess liquid to drain from the paper discs and then place onto an agar plate.

4. Repeat steps 1–3 for the other two agar plates.

5. Incubate the agar plates at 25 °C for 3 days.

6. After 3 days, flood the agar plates with reagent X.

7. Measure the diameter of any clear zones around the paper discs using a ruler.

Fig. 36.2 shows an agar plate at the end of the investigation.

State the precise name of the chemical bond in starch that is hydrolysed by amylase.

Reagent X was used to indicate the presence or absence of starch in the agar plates.

State the name of this reagent and its colour in the presence of starch.

The table below shows the results of the investigation.

Calculate the standard deviation for the data for bacterial species E.

The investigation did not include any control experiment.

Suggest one control experiment that could have been included in this investigation explain its importance.

Suggest one other way in which the method could be changed to improve the validity of the conclusions.

The process of gas exchange involves several specialised cell types.

Fig. 37.1 shows a human bronchiole and surrounding alveoli under a light microscope. Two cell types are labelled R and S.

Complete the table below by inserting, for each cell type:

• the precise name

• one role in gas exchange.

The health campaign claimed that giving up cigarette smoking improves quality of life and prevents smoking-related death.

Evaluate this claim using the data from the graph in Fig. 37.2.

During the campaign, doctors warned that the graph in Fig. 37.2 could not accurately predict the lung function of individual cigarette smokers over time.

Suggest two reasons why.

Cigarette smoking increases an individual’s risk of a heart attack.

A heart attack can lead to respiratory arrest.

Describe how expired air resuscitation is performed to manage an adult in respiratory arrest.