Blood

Which type of blood cell is shown in the annotated drawing?

A Erythrocyte

B Lymphocyte

C Monocyte

D Neutrophil

Your answer

Which technique uses fluorescent markers to tag cells so they can be counted and identified when passed through a laser beam?

A Differential staining

B Flow cytometry

C Gel electrophoresis

D Haemocytometry

Your answer

Hypothyroidism is a condition in which a person produces lower concentrations of the hormone thyroxine than normal. Thyroxine affects metabolic rate and has a role in the control of body temperature. Hypothyroidism causes a variety of symptoms.

* During an investigation, a group of students plan to compare the core body temperature of people with hypothyroidism with people who do not have hypothyroidism.

Describe an experimental plan that would allow the students to collect enough data to be able to complete this investigation.

Your answer should include a method to measure core body temperature and a description of an appropriate statistical test with which to analyse the data.

Extra answer space if required.

Hypothyroidism can affect blood pressure.

Describe how to use a sphygmomanometer to measure the blood pressure of a person.

A person with hypothyroidism compares their blood pressure measurements with a friend who does not have hypothyroidism.

• The person with hypothyroidism has measurements of mmHg.

• The person without hypothyroidism has measurements of mmHg.

Explain what conclusions can be made from these measurements about the effect of hypothyroidism on blood pressure and describe the limitations of this comparison.

Hypothyroidism can affect the concentration of red blood cells in a person’s blood.

State a method that could be used to measure the concentration of red blood cells in a person with hypothyroidism.

One effect of thyroxine on the cardiovascular system is to cause the dilation of arteries.

This is a photomicrograph of an artery.

Draw a plan diagram of the artery in the space below.

On your diagram, label the lumen and the muscle layer of the artery.

The domestic rabbit, Oryctolagus cuniculus domesticus, is a subspecies of European rabbit. It is a popular pet and has been selectively bred for fur colour and other features.

Complete the taxonomic ranks to show the classification of Oryctolagus cuniculus domesticus.

Phylum: Chordata

Class: Mammalia

Order: Lagomorpha

Family: Leporidae

A student bred two pet rabbits several times to produce a total of 48 offspring.

One of the parental rabbits had upright ears and black fur. The other parental rabbit had floppy ears and brown fur.

The student researched the genetics of the two traits (ear position and fur colour) and the family tree of the two rabbits. The student predicted the offspring phenotypes would be:

• 25% black fur, upright ears

• 25% black fur, floppy ears

• 25% brown fur, upright ears

• 25% brown fur, floppy ears

The student used the chi squared (²) test to determine whether the phenotypic ratio of the offspring was significantly different from their expectations.

Their null hypothesis was: ‘There is no difference between the expected phenotypic ratio of the offspring and the observed phenotypic ratio of the offspring.’

The student’s expected and observed results are shown in Table 4.1.

Table 4.1

Calculate² for the results shown in. Use the formula: (i) Table 4.1

Give your answer to 3 significant figures.

A² probability table is shown in. (ii) Table 4.2

Table 4.2

Using your answer to (i) and the data in Table 4.2, state and explain what you can conclude about the student’s results.

Another aspect of rabbit fur colour is colour density.

One gene controls colour density. This gene has several alleles, including:

• C^F, which results in full colour. This allele is dominant to the other two alleles.

• C^S, which results in shaded colour. This allele is dominant to C^A.

• C^A, which results in albino fur (no colour).

A pair of rabbits were bred. 50% of their offspring had full colour, 25% were shaded, and 25% were albino.

State the genotypes of the two parental rabbits that produced these offspring.

Rabbits can inherit genetic diseases.

The probability of a rabbit inheriting a genetic disease can be assessed.

Name the method used for assessing the risk of an animal inheriting a genetic disease.

* Rabbits can also develop diseases such as anaemia and lymphosarcoma that affect the number of erythrocytes and leucocytes in their circulatory system.

If such a disease is suspected, the rabbit’s blood can be sampled and the blood cells can be analysed.

Describe a method that could be used to observe blood cells and a method used to identify blood cells from the blood of a rabbit.

Additional answer space if required.

Rabbits, like all mammals, have a double circulatory system.

Explain the importance to mammals, such as rabbits, of having a double circulatory system.

The diagram shows a blood bag label with information about the stored blood product contained in

Which of the options, A to D, about this stored blood product is correct?

A Contains plasma and erythrocytes with no A or B glycoprotein antigens in the plasma membrane.

B Contains plasma with anti-A and anti-B antibodies and erythrocytes.

C Contains concentrated erythrocytes with A and B glycoprotein antigens in the plasma membrane.

D Contains concentrated erythrocytes with no A and B glycoprotein antigens in the plasma membrane.

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

Fig. 7.1 shows the structures visible in a light micrograph of a generalised animal cell.

Identify the structures labelled D to H in Fig. 7.1.

Describe two functions of structure H and one function of structure J.

The route taken by proteins that are secreted from the cell has been worked out by many different experiments. One series of experiments involved the following steps:

• A virus was modified so that one of its proteins (VSVG) was tagged with green fluorescent protein (GFP).

• Cells were infected with the modified virus.

• The virus produced the tagged protein, VSVG-GFP, using the cells’ organelles, but only when the temperature was reduced from 40 °C to 32 °C.

• This allowed the path through the cell taken by the VSVG-GFP to be followed by fluorescence microscopy from the time the temperature was reduced.

Fig. 7.2 shows the results of one experiment where the distribution of fluorescence within individual cells was followed for up to 600 minutes.

Using Fig. 7.2 and your knowledge of the synthesis and secretion of proteins, identify the organelles corresponding to curves K, L and M on Fig. 7.2.

Give reasons for your answers.

Using Fig. 7.2, estimate the time taken for secretion of VSVG-GFP to reach a maximum.

Vinblastine is a drug used in the treatment of cancer. It inhibits the assembly of microtubules.

Another experiment similar to that described in part (b) was carried out, but the cells were treated with vinblastine before the temperature was reduced from 40° C to 32° C.

When VSVG-GFP fluorescence was followed through the treated cells, only curve M disappeared.

Suggest why.