Thermodynamics/ Enzymes practice questions

How do living systems illustrate the two laws of thermodynamics

1st- transfer of energy between organisms in food chains 2nd- entropy difference between organisms in food chains

How is ATP regenerated

ATP is broken down into ADP, which can be regenerated into ATP with catabolism

How do enzymes increase the rate of chemical reactions

Lowers the level of activation energy and allows the reaction to speed up

which has more free energy? a. glutamic acid + ammonia + ATP b. glutamine + adp + Pi

a. because delta G is negative (exergonic).

how can activator and inhibitor have different effects on an allosterically regulated enzyme

activator binds in a way that stabilizes the active form of an enzyme; inhibitor stabilizes the inactive form

If an enzyme in solution is saturated with substrate, the most effective way to obtain a faster yield of products is to

add more of the enzyme

In most cases, how does ATP transfer energy from exergonic to endergonic reactions in the cell

atp transfers to endergonic when it adds phosphate groups to other molecules (phosphorylating, or, the regeneration of adp)

cellular respiration uses glucose and oxygen, which have high levels of free energy, and release co2 and water, which have low levels of free entropy. is respiration spontaneous or not? is it exergonic or endergonic? what happens to the energy released from glucose.

cellular respiration is spontaneous and exergonic. energy released from glucose is used for cellular work or is transferred to heat.

is the chemical reaction of snapping a glow stick endergonic or exergonic? explain

exergonic because it releases energy in the form of light.

Malonate is an inhibitor of the enzyme succinate dehyrogenase. How would you determine whether malonate is a competitive or noncompetitive inhibitor?

increase concentration of normal substrate (succinate) and observe if the reaction rate increases as this will show malonate as a competitive inhibitor.

describe the forms of energy found in an apple as it grows on a tree, then falls and is digested by someone who eats it

on tree= gravitational potential falls= kinetic digested= chemical

most spontaneous reactions occur slowly. why aren't they instant?

spontaneous=exergonic. High activation energy would cause the reaction rate to be slow

If you place a teaspoon of sugar in the bottom of a glass of water, it will dissolve completely over time. Left longer, crystals will reappear. Explain these observations in terms of entropy

sugar entropy increases when they dissolve. when the water disappears, the sugar forms again bc there isn't enough water to keep them in the solution. this reappearance is a decrease in entropy, which is balanced out by the high entropy of the water vapor.

Why do enzymes only react with specific substrates

the enzyme has a specific shape for its activation site that only the specific substrate can fill that shape to start the reaction

Some bacteria are metabolically active in hot springs because

their enzymes have high optimal temperatures

Why do we break down food

to use the molecules to make ATP for cellular work

How is ATP usable

when ATP is broken down, it drives the chemical reactions for cellular work