Unit 2.5: Cell Communication/Energy and Enzymes

Metabolism

totality of an organism’s chemical reactions

Catabolic pathway

pathways that release energy by breaking down complex molecules ex. cellular respiration

Anabolic pathway

pathways that consume energy to build molecules from simpler ones (ex. amino acid synthesis, protein synthesis)

Exergonic

release energy, spontaneous, change is negative, reactant energy > product energy, breaking bonds, catabolic

Endergonic

requires energy, not spontaneous, change is positive, reactant energy < product energy, building bonds, anabolic

What is the 1st law of energy?

energy cannot be created or destroyed, only transformed (conservation of energy)

What is the 2nd law of energy?

some energy is converted to thermal energy and released as heat

Entropy

measure of molecular randomness

What kind of system is life?

open system

Closed system

no energy in/no energy out, boring, equilibrium for life = death, reaches state of equilibrium

Open system

can’t reach equilibrium as long as it receives inputs and produces outputs, continuous inputs and outputs

What is ATP made of?

sugar (ribose), nitrogenous base (adenine), chain of 3 phosphate groups

Phosphorylation

transfer of phosphate group from ATP to another molecule

Cofactor

help enzymes catalyze (minerals, vitamins)

What happens to enzymes if the temperatue is too cold?

not enough collisions, denatures

What happens to enzymes if the temperature is too hot?

bonds break, denatures

What happens to enzymes if the pH level is to low or high?

enzyme denatures

What do you have to do to keep things organized in a living cell?

put in work

What increases entopy?

exergonic reactions

What decreases entropy?

endergonic reactions

How do you overcome a competitve inhibitor?

add more substrate

Photolysis

plant splitting water molecule to get electrons

What is the final electron acceptor?

oxygen

What happens to cellular respiration if no oxygen is available?

switches to fermentation

What does fermentation not produce?

ATP

What do both photosynthesis and cellular respiration use?

a proton gradient for ATP synthase