OCR GCSE Combined Science A (Gateway) Biology Paper 7 Higher June 2024 question paper J250/07

The length of a bacteria cell is 5.3 m.

What is the length of this cell in mm ?

(1 mm = 1000 m)

5.3 × 10^–6 A

5.3 × 10^–3 B

5.3 × 10³ C

5.3 × 10⁶ D

What are two characteristics of a cell membrane?

A Non-selective barrier and contains plasmids

B Non-selective barrier and contains receptors

C Selective barrier and contains plasmids

D Selective barrier and contains receptors

The diagrams show stages in the hypothesis used to explain the mechanism of enzyme action.

Which term describes the molecule labelled M?

A Active site

B Enzyme

C Lock and key

D Substrate

What is a difference between embryonic stem cells and adult stem cells?

A Adult stem cells are less likely to be rejected when used in transplants.

B Only embryonic stem cells can differentiate.

C Only embryonic stem cells produce a full range of different cell types.

D There are more ethical issues in the use of adult stem cells.

The resolution of a microscope is limited to half the wavelength of light used to see the image.

Our eyes only detect light with a wavelength greater than 400 nm.

What is the approximate resolution of a light microscope?

(1000 nm = 1 m)

A <0.2 m

B ~0.2 m

C ~0.4 m

D >0.4 m

The photograph shows two different blood vessels.

Which statement about these blood vessels is correct?

A Blood flows through blood vessel T at a slower rate.

B Blood vessel S has a thinner muscular wall.

C Blood vessel T has a larger lumen diameter.

D Both blood vessels transport blood to the heart.

Which statement correctly compares mitosis and DNA replication in eukaryotic cells?

A Only DNA replication is part of the cell cycle.

B Only DNA replication occurs inside sub-cellular structures.

C Only mitosis is needed to produce new cells.

D Only mitosis is part of the cell cycle.

The pH inside the small intestine of the human digestive system is between pH 7 and pH 8.

The pH inside the stomach of the human digestive system is between pH 1 and pH 2.

The graph shows the effect of pH on the activity of two enzymes.

Which statement about the enzymes is correct?

A Both enzymes would be denatured inside the small intestine.

B Enzyme Q would be more efficient inside the small intestine compared to enzyme P.

C Neither enzyme would work at its highest activity inside the stomach or small intestine.

D Only enzyme P would be active in the stomach.

Fig. 11.1 and Fig. 11.2 show two different transport vessels in plants.

Fig. 11.1
Fig. 11.2

Xylem vessels
Phloem vessels

The arrows show direction of movement inside the vessels.

Give two reasons why Fig. 11.2 shows phloem vessels.

Compare the type of substances transported in xylem and phloem vessels.

Explain how the transport of substances through xylem changes on a warm day compared with a cold day.

A teacher investigates the effect of different enzymes on starch. They want to find out if the enzyme breaks down the starch into sugar.

This is the method they use:

• Add 1 cm³ of an enzyme to 5 cm³ of starch solution in a boiling tube.

• Leave the mixture for 5 minutes.

• Add Benedict’s solution to the mixture.

• Place the boiling tube in a hot water bath.

• Record the colour of the Benedict’s solution after heating.

Benedict’s solution is a blue solution that, when heated, forms a coloured precipitate if sugar is present.

Fig. 12.1 shows how the teacher tested for the presence of sugar in the mixture.

Fig. 12.1

The teacher repeats the method with different enzymes.

Identify the dependent variable in this investigation.

Suggest one hazard in this investigation and the precaution the teacher should take.

Complete the table.

The concentration of sugar in mixture C stated in the table is not an accurate value.

How can the student tell that it is not an accurate value?

The amount of light absorbed by different colours can be measured.

The graph compares absorbance with the percentage of sugar concentration.

The teacher investigates the light absorbed by the different coloured mixtures.

They record an absorbance of 0.2 for mixture C.

Use the graph to find the sugar concentration of mixture C.

The answer to (i) is outside the range stated in the results table.

Suggest how the student could improve their method to find out how precise their measurement is for mixture C.

Calculate the surface area to volume ratio of agar cube C.

Write your answer in the table.

One of the times recorded is an anomaly.

Identify this anomalous result.

The anomaly was due to random error.

Suggest one random error that could have caused the anomaly.

Describe and explain the pattern in the results.

Doctors can test your eye reflexes by touching the eye to make you blink. Fig. 14.1 shows the reflex arc involved in blinking.

Fig. 14.1

Explain how the components of the nervous system produce the response of blinking. Use Fig. 14.1.

The endocrine system also controls the body.

Which endocrine gland releases thyroxine into the blood?

Describe two effects of adrenaline on the human body.

Hormones are used in the contraceptive pill.

Explain how the progesterone contraceptive pill prevents pregnancy.

Identify hormone Y.

Explain why hormone X is glucagon.

Compare the functions of glucagon and hormone Y.

The diagram shows apparatus used to investigate photosynthesis.

The number of oxygen bubbles released each second indicates the rate of photosynthesis.

A student counts the number of oxygen bubbles released from the pondweed in 2 minutes.

They use their result to correctly calculate a rate of 0.525 bubbles per second.

How many bubbles did the student count in the 2 minutes?

* The student develops their investigation to find the effect of light intensity on the rate of photosynthesis.

Describe how they should develop their investigation. Explain how a change in light intensity will affect the rate of photosynthesis.

The diagram shows drawings of red blood cells.

Explain two ways red blood cells are adapted to their function.

This diagram shows a frog heart.

Describe the function of the structure labelled Z.

Explain why the structure of the frog heart makes it less efficient than a human heart.