OCR GCSE Combined Science A (Gateway) Biology Paper 7 Higher June 2025 question paper J250/07

What is the main source of testosterone in the human body?

A Adrenal glands

B Pancreas

C Pituitary gland

D Testes

Which substance has a net outward movement from plants during the day?

A Nitrates

B Nitrogen

C Oxygen

D Urea

What is the definition of resolution ?

A How large an image is compared to the object.

B The shortest distance apart that two objects can be and still be seen as separate objects.

C The magnification of an eyepiece and an objective lens multiplied together.

D The wavelength of light used to view an object.

Which statement describes the structure of DNA?

A A monomer made of one strand

B A monomer made of two strands

C A polymer made of one strand

D A polymer made of two strands

Which process do cells go through when they specialise?

A Differentiation

B Meiosis

C Mitosis

D Osmosis

A scientist is investigating the action of amylase enzymes on the digestion of starch into maltose.

What would increase the rate of reaction?

A Decreasing the enzyme concentration

B Decreasing the pH to 2

C Increasing the pH to 7

D Increasing the temperature to 70 C

How is this image of a cell generated?

A Electron microscope

B Hand lens

C Light microscope

D X-ray machine

Which sub-cellular structure is not found in eukaryotic cells?

A Chloroplast

B Nucleus

C Plasmid

D Ribosome

Plants need to move water and other molecules through their stems.

A student uses this apparatus to estimate water uptake by a leafy shoot.

State the name of this apparatus.

Describe how the student can use this apparatus to find the rate that the gas bubble moves in cm/minute.

To find this estimate of water uptake in 10 minutes, the student took measurements for 60 minutes and divided their answer by 6.

Suggest why they did this.

The student wanted to check the reproducibility of their results.

State one way that they could do this.

The student wants to extend their experiment to investigate the effect of leaf area on the rate of water uptake.

Suggest how the student could measure the area of a leaf.

The student then investigates the number of stomata on the upper and the lower surfaces of one of the leaves from the shoot.

The table shows their results.

Calculate the mean number of stomata on the upper surface.

Mean number of stomata =........ per mm²

The mean number of stomata on the lower surface of the student’s leaf is 49 per mm². (i)

Use this value and the graph to find the transpiration rate for this plant.

Transpiration rate =........ arbitrary units

Suggest two conclusions that can be made from the trends shown in this graph.

The image shows cheek cells magnified at 550×.

Calculate the actual length of the cell marked X.

Use the line on the image.

State the function of the sub-cellular structure labelled Y.

Photosynthesis is affected by many factors. The graph shows how the rate of photosynthesis in a plant is affected by varying light intensity.

Describe how light intensity affects the rate of photosynthesis.

Include how the graph changes from A–B, and B–C.

A student set up the apparatus below to measure how light intensity affects the rate of photosynthesis in a pond plant.

Suggest two variables they should have controlled in their investigation.

Describe how they could have done this.

This is controlled by........

This is controlled by........

Many biological processes involve enzymes.

Explain how enzymes increase the rate of biological processes.

Explain how temperature affects the progress of an enzyme-controlled reaction.

Many lizards have a body temperature that matches the external temperature.

In the morning, these lizards often lie in the sun before they can become active and hunt.

Explain why they need to lie in the sun before they can hunt.

Many large multicellular organisms have a mass transport system to supply all cells with their requirements.

The diagram shows a mammal’s heart.

Explain how the left ventricle is adapted to carry out its function.

Explain why small organisms like amoeba do not need a transport system.

Animals produce coordinated responses when there are changes to their internal or external environments.

An animal’s nervous system is important in coordinating responses.

Put a tick (✓) next to any statements that correctly describe the functions of parts of an animal’s

Hormones are responsible for coordinating longer lasting responses.

Describe how low thyroxine levels would stimulate a response by the body.

Use the words in the list within your answer.

hypothalamus pituitary gland TRH TSH

* IVF is a treatment some people use when they have difficulty getting pregnant.

This treatment involves the use of hormones involved in the menstrual cycle and eggs being fertilised by sperm in a laboratory.

Embryos are then transferred into a female’s uterus.

This treatment has different results depending on age:

• females under 35 have a 32% success rate

• females aged 40–42 have an 11% success rate.

Name the hormones which are used in IVF treatment and explain their function. Evaluate the effectiveness of using IVF treatment.

Many substances move in and out of cells, maintaining the internal environment of the organism.

State the name given to the type of transport where ions move against their concentration gradient.

Water can move in and out of plant cells.

Potato chips can be used to demonstrate this type of transport.

The mass of three potato chips are measured at the start of the experiment and after 20 minutes in 3 different concentrations of sugar solution.

The table shows these results.

Calculate the percentage change in mass at 0.0 mol / cm³.

Explain the percentage change in mass shown by the potato chip in the 0.5 mol / cm³ solution.