AOS 2 EXAM QUESTIONS Flashcards
give one example of a type of protein within a yeast cell that may change in concentration and explain why this change is necessary
VCAA 2021 Q2a
Enzyme: If there is a change in substrate concentration, then more or less enzyme may be produced to conserve ATP
OR
Structural protein: repair or synthesis of organelles if organelles are damaged due to increased or decreased temperature
OR
Regulatory/repressor protein: more or less repressor protein is required to inhibit or promote a reaction when there is a change in substrate availability
OR
Transcription factors: more or less is required for transcription if environmental conditions result in increased or decreased need for protein synthesis.
why is biofuel more environmentally friendly than fossil fuels
ACED 2022 TRIAL 2
- Biofuels are renewable, whereas fossil fuels are not renewable.
- Biofuels are (theoretically) carbon-neutral, whereas fossil fuels are not carbon-neutral.
- Biofuels recycle waste from industries such as crops, farming and forestry; fossil fuels are derived from raw materials.
why does temperature need to be controlled in photosynthesis experiment
A+ 2022 Q3a
- photosynthesis is catalysed by enzymes which produce the highest rate of photosynthesis at its optimal temperature
- temperature higher than its optimal causes the enzymes to denature, changing its shape
would green wavelengths enable the greatest rate of photosynthesis
A+ 2022 Q3b
- chlorophyll reflects green light an dhence appears green
- red and blue wavelengths are absorbed at a greater rate for photosynthesis
why is the rate of reaction higher in location B than A of the chloroplast
NHT 2017 Q5biii
- this may be explained by B having more chlorophyll to trap light
- this may be explained by region B membranes containing a higher concentration of
enzymes, which would lead to a greater rate of reaction.
what occurs within cells of the leaves that result in the formation of the bubbles in elodea aquarium
NHT 2018 Q1a
Chlorophyll absorbs light energy, water is split to form hydrogen ions or oxygen gas, and oxygen
will diffuse out through the plasma membrane.
explain difference in photosynthesis in low light intensity compared to high light intensity
NHT 2018 Q1bii
At low light intensities the amount of ATP and NADPH produced is smaller OR there is less
energy to produce H + as fewer chlorophyll molecules are excited.
- in the carbon fixation/light-independent stage, less glucose is produced at lower light
intensities.
if the temperature increased above the optimal for cellular activity, would the activity of theproteins of gene expression, increase, decrease or stay the same?
NHT 2022 Q1bii
- An increase in temperature would lead to decreased activity of the enzyme
- and the eventual denaturation of enzymes
- substrates no longer able to fit or bind to the active site of the enzyme.
consider the reactions of photosynthesis. Why would it be important to maintain the temperature
within narrow limits in a commercial greenhouse? Justify your answer.
VCAA 2020 Q3a
- photosynthesis is regulated by enzymes.
- enzymes have an optimum temperature.
- enzymes may denature at high temperatures or activity is decreased at lower temperatures.
- the greater the rate of reaction the more growth will occur.
scientists are developing a new material to cover greenhouses, which can split incoming light and
convert the rays from green wavelengths into red wavelengths. explain how this new material increases crop yields.
VCAA 2020 Q3b
- green plants reflect green light OR do not use it for photosynthesis.
- red light is used in photosynthesis OR increased availability of light for photosynthesis.
- more glucose is produced due to greater rate of photosynthesis.
in plants and algae, photosynthesis is carried out in chloroplasts. It is thought that chloroplasts
originated from bacteria.
Describe two features of chloroplasts that support the theory that chloroplasts originated from bacteria.
VCAA 2020 Q3c
- chloroplasts have their own circular DNA like the DNA found in bacteria.
- chloroplasts have their own ribosomes.
- new chloroplasts are made by existing chloroplasts dividing in a similar way to how bacterial cells reproduce.
- chloroplasts have a double membrane, one eukaryotic and one prokaryotic.
- they have a similar size and appearance.
in most mammalian cells the ATP produced from the complete breakdown of glucose occurs by a series of chemical reactions. coenzymes also play an important role in glucose metabolism.
describe the roles of coenzymes in the formation of ATP.
VCAA 2023 Q4a
- coenzymes, such as NAD and FAD, carry hydrogen ions and/or electrons to the electron transport chain in aerobic cellular respiration.
- enables ADP and Pi to join, forming ATP.
plant materials containing cellulose and other polysaccharides are reacted with acids to break them down to produce glucose. this glucose is then used by yeast cells for fermentation.
a. why is fermentation important for yeast cells?
b. What are the products of fermentation in yeast cells?
VCAA 2016 2a & b
a. to provide energy or ATP
b.
- ethanol/alcohol
- carbon dioxide
- ATP
- (energy is not accepted)
prediction of the change in oxygen concentration of the mixture in the reaction tube after the addition of each substance and give a reason for your prediction. Suspension of mitochondria
glucose: no change - glucose is not metabolised (broken down) by the mitochondria.
pyruvate: decrease - pyruvate is a substrate of the Krebs
prediction of the change in oxygen concentration of the mixture in the reaction tube after the addition of each substance and give a reason for your prediction. Cytosol of cells from which the mitochondria had been removed
glucose: no change - glycolysis is anaerobic (or glucose converted to pyruvate but no mitochondria so oxygen is not used).
pyruvate: no change - no aerobic breakdown of pyruvate.
