AS Biology Revision (Chapter 7-11)

How does sucrose move from chloroplasts to the phloem?

 

1        mass flow

2        apoplast pathway

3        symplast pathway

• all the above

• 1 and 2

• 1 and 3

• 2 and 3

What is the role of ATP in a companion cell when sucrose is loaded into a sieve tube element?

 

• moving sucrose into the sieve tube element

• removing protons out of the cytoplasm of the companion cell

• removing protons from the sieve tube element.

• taking up sucrose into the cytoplasm of the companion cell

Different substances, such as sucrose and amino acids, can move in different directions in the phloem sieve tubes.

 

Which statement explains this?

• Active transport occurs in some phloem sieve tubes and mass flow occurs in other phloem sieve tubes.

• Both active transport and mass flow occur in each individual phloem sieve tube.

• Mass flow occurs in both directions at the same time in each individual phloem sieve tube.

• Mass flow occurs in different directions in different phloem sieve tubes at the same time.

Which feature of xylem vessel elements helps adhesion during transpiration?

• lignin forms an incomplete secondary wall

• new vessels carry extra water as the plants grow

• there are no cross walls between vessel elements

• the vessel elements form a narrow tube

Which type of tissue is present in the walls of all blood vessels?

• elastic

• endothelial

• fibrous

• smooth muscle

Which feature enables the aorta to withstand high pressure at ventricular systole?

• collagen fibres and elastin fibres

• collagen fibres and semilunar valves

• elastin fibres and large lumen

• semilunar valves and smooth muscle

Which statement correctly identifies a similarity between blood plasma and tissue fluid?

• Protein is found in equal concentration in both blood plasma and tissue fluid.

• The blood plasma is under the same pressure as the tissue fluid.

• The water potential of the blood plasma and tissue fluid are equal.

• White blood cells are found in both blood plasma and tissue fluid.

An oxygen molecule diffuses directly from the air in an alveolus to haemoglobin in a red blood cell.

 

What is the minimum number of cell surface membranes through which this molecule must pass?

• 2

• 3

• 4

• 5

When red cells leave the lungs, haemoglobin is 98 % saturated.

 

How many molecules of oxygen will be carried by the majority of haemoglobin molecules?

• 2

• 4

• 6

• 8

What is systolic blood pressure?

• the blood pressure in the arteries when the heart is relaxing

• the blood pressure in the left ventricle at the end of a contraction

• the maximum blood pressure in the arteries

• the maximum blood pressure in the right ventricle