Which of the following is part of a haemoglobin molecule?

• calcium

• iron

• vitamin C

• vitamin D

The diagram shows a human kidney and its blood supply.
Compared with the blood in vessel P, the blood in Q has:

• less urea and more oxygen.

• less urea and less oxygen.

• more urea and less oxygen.

• more urea and more oxygen.

In which direction does blood circulate in the body?

• from the left ventricle through the tricuspid valve

• from the limbs to the right atrium

• from the lungs along the pulmonary artery

• from the right ventricle to the right atrium

The diagram shows a section through the heart with blood vessels, seen from the front.
In one circulation of the body, excluding the lungs, in which order does blood flow through the vessels shown?

• 1 → 2 → 4 → 3

• 2 → 3 → 1 → 4

• 3 → 4 → 1 → 2

• 4 → 3 → 1 → 2

What is the correct sequence for blood being pumped from the heart to the lungs?

• left atrium → left ventricle → pulmonary artery

• left atrium → left ventricle → pulmonary vein

• right atrium → right ventricle → pulmonary artery

• right atrium → right ventricle → pulmonary vein

Why is the circulatory system of mammals described as a double circulation?

• Blood flows firstly through arteries and then through veins.

• Blood flows through the heart twice on one complete circuit of the body.

• In the heart, blood flows firstly through atria and then through ventricles.

• The atria and the ventricles contract alternately.

What is carried by the xylem?

• chlorophyll

• mineral ions

• starch

• sugars

Which substance, needed for protein synthesis, is carried into a leaf from the stem?

• carbon dioxide

• nitrate

• oxygen

• starch

Which substances are dissolved in human blood plasma?

• carbon dioxide, haemoglobin and glucose

• carbon dioxide, oxygen and haemoglobin

• glucose, hormones and urea

• oxygen, urea and starch

Which chamber of the heart has the thickest muscle wall?

• left atrium

• left ventricle

• right atrium

• right ventricle

What is carried by the xylem in plants?

• A) chlorophyll

• B) mineral ions

• C) starch

• D) sugars

What is the correct sequence for blood being pumped from the heart to the lungs?

• A) left atrium → left ventricle → pulmonary artery

• B) left atrium → left ventricle → pulmonary vein

• C) right atrium → right ventricle → pulmonary artery

• D) right atrium → right ventricle → pulmonary vein

Why is the circulatory system of mammals described as a double circulation?

• A) Blood flows firstly through arteries and then through veins.

• B) Blood flows through the heart twice on one complete circuit of the body.

• C) In the heart, blood flows firstly through atria and then through ventricles.

• D) The atria and the ventricles contract alternately.

Which blood vessel, if it becomes blocked, could lead directly to a heart attack?

• A) coronary artery

• B) pulmonary artery

• C) pulmonary vein

• D) vena cava

A hospital patient who is feeling unwell is given a blood test. The results of the blood test show a very low level of platelets.
What effect will this have?

• A) The blood will be unable to transport nutrients, hormones and carbon dioxide.

• B) The blood will not be able to carry as much oxygen to the tissues as normal.

• C) There will be a greater risk of bleeding because the blood will take longer to clot.

• D) There will be a greater risk of infection because the blood cannot make antibodies.

Which statement describes transpiration?

• A) evaporation of water from leaf mesophyll cells

• B) intake of water from the atmosphere through the stomata

• C) transport of water through xylem tissue to the leaves

• D) uptake of water by root hairs in the soil

Oxygenated blood returns to the heart from the lungs in vessel X and leaves the heart to circulate
around the body in vessel Y.
What are X and Y?

Which is a description of translocation?

• A) movement of amino acids and sucrose from sink to source

• B) movement of amino acids and sucrose from source to sink

• C) movement of water down a water potential gradient

• D) movement of water up a water potential gradient

Active transport is the movement of:

• A) molecules from a region of their higher concentration to a region of their lower concentration.

• B) particles from a region of lower concentration to a region of higher concentration using energy from respiration.

• C) urine by relaxation of a sphincter muscle in the bladder.

• D) water through a partially permeable membrane from a more dilute to a more concentrated solution.

In which order does water pass through the cells of a plant, as the water travels from the roots to a leaf?

• A) mesophyll cells → root hair → root cortex → xylem

• B) root cortex → root hair → xylem → mesophyll cells

• C) root hair → mesophyll cells → root cortex → xylem

• D) root hair → root cortex → xylem → mesophyll cells

The diagram shows a cross-section through a plant root.
Q shows the part that is stained red when the root is placed in water containing a red dye.
What is found at Q?

• A) guard cells

• B) palisade cells

• C) phloem

• D) xylem

A decrease in which factor normally causes transpiration rate to increase?

• A) humidity

• B) light intensity

• C) stomatal opening

• D) temperature