Biology study guide chapter 6

Kinetic vs potential energy?

Kinetic energy: energy of motion

Potential energy: stored energy based on position/structure

What is chemical energy?

Potential energy stored in chemical bonds

Catabolic vs Anabolic Reactions what is the Difference?

Catabolic: breaks down molecules → releases energy

Anabolic: builds molecules → requires energy

Which is exergonic/endergonic? (out of catabolic and anabolic)

Catabolic = exergonic

Anabolic = endergonic

what is a Reactant

Starting material in a reaction

what is a product

Substance formed after the reaction occured

what is a substrate

A reactant an enzyme acts on

what is a enzyme

Protein that speeds up reactions

what is activation energy

the minimum amount of energy required to initiate a chemical reaction

Endergonic vs Exergonic what is the difference? (energy wise and is it spontaneous or not)

Exergonic: releases energy, spontaneous

Endergonic: requires energy, not spontaneous

What work do cells do?

Chemical (building molecules)

Transport (moving substances)

Mechanical (movement)

Where does energy come from for cells to do work?

ATP (from food breakdown)

Role of ATP in metabolism?

Main energy carrier in cells

What part of the molecule is separated to release a large amount of
energy from ATP? Is that separation by hydrolysis or dehydration synthesis? What are products of this reaction?

Terminal phosphate group - Hydrolysis
Products: ADP + phosphate + energy

What type of molecule are most enzymes?

Protein

Explain how enzymes are specific for their substrates

Shape fits substrate

What is the term for the part of the enzyme that holds the substrate?

Active site

Describe induced fit.

Enzyme changes shape slightly to fit substrate better

Describe three possible mechanisms by which enzymes lower activation energy.

Bring reactants together

Stress bonds (make breaking easier)

Create favorable environment (e.g., proper pH)

Be able to predict how conditions like temperature can affect an enzyme’s ability to function.

Too low = slows down an enzyme

Too high = denatures an enzyme

Be able to predict how conditions like pH can affect an enzyme’s ability to function.

Each enzyme has optimal pH

Wrong pH = denature/change shape

Be able to predict how conditions like interaction with inhibitors or activators can affect an enzyme’s ability to function

Inhibitors decrease activity

Activators increase activity

Explain competitive inhibition

Compete with substrate for the active site

Can be overcome by adding more substrate

Explain non-competitive inhibition (talk about site, enzymes shape and if it works, and can it be fixed)

Bind to a different site (allosteric site)

Change enzyme shape = active site no longer works

Cannot be fixed by adding more substrate

Explain regulation of enzyme pathways

Cells regulate pathways to conserve energy, mainly through feedback inhibition, where the final product binds to an enzyme early in the pathway (at an allosteric site) and shuts the process down. Regulation also occurs through allosteric activation or inhibition, where molecules bind away from the active site to turn enzymes on or off.

Explain allosteric activation

molecule binds to an enzyme at a site other than the active site (the allosteric site), causing a conformational change that increases the enzyme’s efficiency and activity

What is an enzyme pathway?

A series of reactions where each step is controlled by a different enzyme