QnA Revision 2 Flashcards
Why (or why not) might a plant be able to swap between C3 and C4 photosynthesis, or vice versa.
You need to consider the fact that C4 have anatomical and biochemical differences compared to C3 as C4 plants have PEPc and spatial segregation (with specialised cells that one collects CO2 and the other is for Calvin cycle). It is not easy for C3 plants to be C4.
What are similarities and differences between autotrophic and heterotrophic modes of “nutrition”?
Autotrophic - makes their own food, obtains energy from the light, can take in inoragnic carbon source (CO2)
Heterotrophic - needs to eat, cannot make their own food, only ingests organic carbon
Both needs to release energy from the food they ingest
Explain how compartmentation is important for function of chloroplasts and mitochondria?
Compartmentation helps isolate the specific environments needed to do the specific processes within mitochondria and chloroplast. One example is that it helps separates the concentration of protons (chemiosmosis) which is useful for ATP synthesis
What might have
caused his blindness? What could the boy do to achieve a healthier diet? What help could he be
given? How could this situation have been prevented? (Q3 Murray)
His diet does not compromise of any vitamins such as vitamin A or retinol that helps improve his sight. His diet only consists of not very complex carbohydrate. He could have prevented this by starting to have a diet comprised of vitamins or take vitamin supplements. His diet also lacks essential amino acids as the protein could have helped repair his eyesight to a certain extent. His diet also lacks copper, a mineral used in the nervous system as it helps maintain the structure (myelin sheath) and helps in signal transduction.
What might happen if a fish had a mutation that caused a methyl group (-CH3) to be substituted
for the OH group on the first ring of cholesterol?
The OH group in cholesterol is used as an anchor between phospholipids which helps it stop from moving. The O in OH is attracted to the phospholipid head since they’re both polar. The cholesterol is important for controlling the fluidity of the phospholipid membrane. It is also important for packing the phospholipid membrane tightly to avoid water from coming in. This avoids from making the cell to be hypotonic and the contents of the cell to be severely diluted which could stop the cells from functioning.
What might be the consequence to a salamander’s cell biology if it had a mutation that
prevented the calcium channel in the sarcoplasmic reticulum from binding ATP?
The sarcoplasmic reticulum holds calcium ions that when a stimuli is received, the calcium ions are released, transported by binds to the troponin on the tropomyosin which then changes the structure that exposes the myosin binding site. The actin will then attach itself on the binding site and the power stroke begins. If the calcium channel is unable to bind with ATP, it cannot release the calcium channels. This is because the calcium channels initially contain amino acids where they may be initially repulsed with each other but due to the phosphate group binding, it becomes attracted with each other which causes the other side of the channel to open up
Throughout pregnancy the concentration of CRH in the blood progressively rises to reach 1,000
times that of non-pregnant levels. What effects would you expect that might have on the physiology
of the pregnant woman.
In pregnancy, cortisol is an essential component that helps during the final stages of pregnancy where there is a positive feedback on cortisol to help push the baby out. However, this cortisol comes from the baby not the mom. A lot of the CRH produced from the mom goes towards the baby to initiate contractions and the initial stages of labor. When contractions happen, this sends a signal to the hypothalamus of the mom to stimulate more release of oxytocin.
Discuss the implication of cortisol exerting negative feedback on the hypothalamus
Hypothalamus receives stress stimuli so CRH is released and goes towards the pituitary gland to release ACTH. ACTH then travels to the adrenal medulla to the adrenal cortex to release cortisol. Cortisol then breaks down fats and proteins to reduce the stress or adapt to the stress stimuli
Not a Review Q: Where does cortisol come from?
The adrenal cortex. Adrenaline comes form the adrenal gland while cortisol comes from the adrenal cortex,
