Cell Biology Questions

An organelle found in plant and algae cells where photosynthesis occurs

Pigment (staring at 40%) absorbing 70% of light around 430 nm, then stays above zero (but next to nothing) until peaks around 680 nm

enzymes must be "turned off" and then "turned on" again as substrate accumulates or more product is required

Cofactors can be permanently bound to the active site or may bind loosely with the substrate during catalysis

Changes in H+ concentration can disrupt hydrogen bond interactions that help maintain enzyme structure

ATP is made up of the nitrogenous base adenine, bonded to ribose and a chain of three phosphate groups. When a phosphate group is hydrolyzed, energy is released in an exergonic reaction. The exergonic release of the phosphate group is used to do the endergonic work of a cell.

Increase in product concentration decreases opportunity for additional substrate, as more product in area = lower chance of collision. The reaction rate slows.

the concentration of hydrogen (H+) ions in a solution

Initial increases in substrate concentration increase the reaction rate, as more substrates = more opportunities to collide with enzyme. However, substrate saturation will eventually occur, and there will be no further increase in the reaction rate.

Assuming unlimited substrate, more enzymes will lead to a faster reaction rate because there is a greater opportunity for substrates to collide with the active site

Within a chemical pathway, the product of one reaction can serve as a reactant in a subsequent reaction

1) a CO2 molecule is removed2) electrons are stripped to convert NAD+ to NADH3) coenzyme A joins the remaining two-carbon fragments to form acetyl CoA, which then enters the citric acid cycle.

the part of a system's energy that is able to perform work when the temperature of a system is uniform

phase where the DNA molecules double their content

Yes; they are not chemically changed by the reaction

The reaction rate initially increases, as the increased speed of molecular movement results in increased frequency of enzyme-substrate collisions. However, temperature increases outside the optimum range will result in enzyme denaturation.

The use of a reaction that releases energy (exergonic) to drive a reaction that requires energy (endergonic)

A reaction that requires energy to proceed and absorbs free energy from the system

by lowering the activation energy of the reaction without altering the free-energy change of the reaction

Feedback inhibition is a type of allosteric inhibition that occurs when the end product on an enzymatic pathway can switch off its pathway by binding to the allosteric site of an enzyme in the pathway.