progress task 3

Question 1

which of the following is NOT an example of an anabolic reaction?

A: photosynthesis
B: glycolysis
C: protein synthesis
D: an endergonic reaction

Answer 1

B: glycolysis

Question 2

a plant cell was placed into a hypertonic solution but did not have the same outcome as an animal cell. explain why. [2]

Answer 2

because plant cells contain a cell wall whereas animals do not [1],
then the cell wall remains rigid and prevents the cell from shrinking,
therefore the plant cell becomes plasmolysed instead of crenated [1].

Question 3

the ACTN3 gene is a gene in humans known as the ‘sprinters gene’ that codes for a protein (actinin 3). for those people with the ‘ACTN3 sprinters allele’ this enables people to sprint faster due to the protein structure of their muscle fibers. people who have the other allele are not as good at sprinting.

referring to protein structure, and the organelle involved with forming the functional protein, explain why the protein in people with the other allele will not function the same as the sprinter’s allele. [3]

Answer 3

because the primary structure/sequence of amino acids have changed [1],
then it will be folded differently in the rough endoplasmic reticulum [1],
therefore producing a different tertiary/3D structure with a different function [1].

Question 4

students used mitochondria in suspension to determine the effect of different substrates on the activity of aerobic cellular respiration. the mitochondria had been removed from human skin cells. they measured a change in oxygen concentration after 10 mins, using an oxygen probe.

glycogen - no change
glucose - no change
pyruvate - decrease

explain why there was a decrease in oxygen concentration when pyruvate was the substrate. [3]

Answer 4

because pyruvate is an input to the kreb’s cycle in the mitochondrial matrix [1],
then it will be used to produce NADH, allowing the electron transport chain to occur [1],
therefore oxygen will be used in the ETC [1].

Question 5

An experiment was set up to test the effect of the colour of light on photosynthesis rates in spinach leaves. Four beakers were prepared, each one containing 20 spinach leaf discs with the air removed. One beaker was wrapped in red cellophane, one in blue cellophane, one in green cellophane, one in yellow cellophane and one in clear cellophane for white light.
White light from a lamp shone on each beaker. The rate of photosynthesis in the spinach leaves in each beaker was measured in terms of the number of floating leaf discs after 10 minutes. The figure below shows the experimental setup and results.

red: 14 discs floating
yellow: 9
green: 4
blue: 16
white: 20

outline a controlled experiment that this student could have used. [5]

Answer 5

[1] there will be two groups: an experimental group and a control group.
in the experimental group, colour of light will be changed by using red, blue, green and yellow cellophane.
[1] add 50cm3 of water to a beaker.
add 20 spinach discs with air removed to the beaker.
add red celllophane over beaker.
add light 10cm away from beaker.
all other variables will be kept the same, such as species of spinach and light intensity.
[1] the rate of photosynthesis will be measured by the number of floating leaf discs after 10 minutes.
[1] repeat above for other light colours.
for the control group, repeat with no light.
repeat many times.
[1] if ___ light is the best for photosynthesis, then there will be the most spinach leaf discs floating after 10 minutes under the ___ CELLOPHANE.