Biology exam qs that i didn't get full marks

Question 1

Zinc ions are necessary for the enzyme carbonic anhydrase to work
which statement correctly describes the nature and function of zinc ions in their interactions with carbonic anhydrase?
A) inorganic ions and coenzymes
B) Vitamins and prosthetic groups
C) Inorganic ions and prosthetic groups
D) Vitamins and coenzymes

Answer 1

c

Question 2

Triglycerides contain 3 elements
M and N are formulae for 2 macromolecules
c55 h98 o6 - M N- C18 H36 O16
which of the formulae corresponds to a triglyceride
explain

Answer 2

M because of a high ratio of hydrogen to oxygen

Question 3

Explain how the structure of phospholipids allow them to form the bilayer of a plasma membrane (3)

Answer 3

Phospholipids have hydrophobic tails , the tails point inwards due to the membrane outside being aqueous and hydrophobic tails repel water , they however have also hydrophilic heads which point outwards towards the aqueous medium outside. These tails prevent water from coming into the cell by osmosis and the cell from swelling

Question 4

Describe how the second amino acid would bond to cysteine in forming the primary structure of a protein (3)

Answer 4

The second amino acid would form covalent peptide bonds between the amine group of it self and the carboxyl group of the other amino acid through condensation, that occurs between peptide chains.

Question 5

3. The rate of transpiration of water can be estimated by recording the rate of water uptake using a potometer.
   Two potometers were set up, one with large leaves and one with small leaves.
   A calibrated capillary tube that had a diameter of 1 mm was used to introduce the bubble.
   Which of the options, A to D, shows the most appropriate units to compare the rate of transpiration of large
   leaves compared to small leaves?

A mm2 cm−1 min−1
B mm3 cm−1 min
C mm2 cm−2 min−1
D mm3 cm−2 min−1

Answer 5

D

Question 6

Mistletoe is a plant parasite that lives on the stems of other plants. It survives by removing water and
assimilates from the host plant.
The mistletoe binds to the stem of the host plant and grows a specialised root-like tissue called a haustorium
that attaches to different tissues in the stem.
One species of mistletoe, Viscum minimum, contains no chloroplasts.
Which of the options, A to D, explains why V. minimum does not need chloroplasts?

A the haustorium of V. minimum attaches to sieve tube elements
B the haustorium of V. minimum attaches to xylem vessels
C the haustorium of V. minimum attaches to meristem cells
D the haustorium of V. minimum attaches to cambium tissue

Answer 6

A

Question 7

14. Which of the following statements, A to D, describes the movement of water across plant roots?
    A The Casparian strip blocks movement by the symplast pathway.
    B The symplast pathway requires water to cross partially permeable membranes.
    C Water moves from the soil to the root hair cells up a water potential gradient.
    D Water moves through the leaves only by the symplast pathway and across the roots only by the
    apoplast pathway

Answer 7

b

Question 8

16. Which of the following statements, A to D, does NOT correctly describe the structure or formation of plant
    vascular tissues?
    A Companion cells are linked to xylem vessels by plasmodesmata.
    B Mature sieve tube elements do not contain nuclei.
    C Phloem and xylem are formed by differentiation of vascular meristems.
    D Xylem vessels have non-lignified pits to allow movement in and out.

Answer 8

A

Question 9

19. Which of the following, A to D, is not an adaptation to reduce water loss in plants?

A an extensive root system that extends far from the plant
B leaves that are reduced to spines that prevent damage from animals
C the ability to store carbon dioxide so stomata only need to open at night
D the surface covered in reflective hairs

Answer 9

A

Question 10

. Translocation occurs through the sieve elements by …………………1………………… . Sucrose is
loaded into the phloem at regions of the plant known as …………………2………………… . This mechanism
is …………………3………………… . The addition of sucrose …………………4………………… the water
potential of the sieve element sap. This causes water to enter from surrounding tissues by
…………………5………………… which in turn increases the …………………6………………… of the
sap.
Which words correctly complete the numbered gaps 1–6?
1 2 3 4 5 6
A active transport sources active raises osmosis concentration
B mass flow sources active lowers active transport pressure
C mass flow sinks passive raises diffusion concentration
D mass flow sources active lowers osmosis pressure

Answer 10

d