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Which three of molecules could be linked together to form a ribonucleotide?
- Ribose sugar
- Phosphate group
- Nitrogenous base
Describe the role of dynein arms in the structure and function of flagella
Dynein arms serve to change conformation in response to the hydrolysis of ATP such that they cause microtubules in the flagella to slide past each other and cause the flagella to move
In photosynthesis in green plants, how is light energy collected and transmitted through the light reactions?
Light energy is absorbed by antenna chlorophyll molecules in light harvesting complexes of photosystems. That energy s transferred among other chlorophyll molecules until it is used to excite electrons derived from splitting water. The excited electrons are passed along proteins in the e-transport chain; eventually the energy is used to reduce NADP+ and NADPH
Why is cyclic electron flow needed in photosynthesis, in addition to linear electron flow?
It is needed in photosynthesis to generate additional ATP, since more ATP than NADPH is needed in the Calvin cycle
Describe the differences between phagocytosis, pinocytosis and membrane-mediated-endocytosis
- Phagocytosis involves an active pushing-out of the plasma membrane via the use of cytoskeletal fibers and motor proteins to surround and engulf large particles.
- Pinocytosis involves an invagination of the plasma membrane in order to non-selectively trap small particles and molecules in the fluid around the cell.
- Membrane-mediated endocytosis is similar to pinocytosis, except that receptors on the plasma membrane selectively bind specific molecules
Describe the differences between competitive and non-competitive inhibition of enzyme action.
- Non-competitive inhibition slows enzymatic action by changing the shape of the enzyme
- competitive inhibition slows enzymatic action by the inhibitor blocking the regular substrate from accessing the active site.
At which step of glycolysis is the 6-carbon reactant split into 3-carbon products?
When Fructose 1, 6 bisphosphate becomes Glyceraldehyde
Describe the mechanism and role of "phosphorylation cascades" in signal transduction
- A phosphorylation cascade is a sequence of enzymatic events where kinase enzymes activate other ones by phosphorylating them
- This allows small amounts of signal to become effective quickly, ultimately activating enzymes/proteins that carry out a specific cellular function