Biology chapter 6 test

What is metabolism

the total of an organisms chemical reaction

what is the difference between kinetic and potential energy

potential energy is based on spatial arrangement and position while kinetic is based on relative motion

which reaction increases entropy

exergonic

which reaction decreases entropy

endergonic

what are the characteristic of endergonic reactions

products have more energy than reactants

delta g is positive

free energy is absorbed (cold)

non spontaneous

anabolic

uphill reaction

stable to unstable

decreases entropy

what are the characteristic of exergonic reaction

reactants have more energy than products

downhill reaction

increases entropy

stable to unstable

spontaneous

delta g is negative

free energy released (hot)

catabolic

what is an example of an exergonic reaction

cellular respiration

what is an example of an endergonic reaction

photosynthesis

what is the role of ATP in metabolism

provides energy to do cellular work

what is the purpose of a catalyst

speeds up a chemical reaction without being consumed by it

what is the difference between competitive and noncompetitive inhibitors

competitive bonds at active site

noncompetitive bonds not at active site

what is the role of an allosteric activator

lock it in the active position

what is the role of an allosteric inhibitor

lock it in the inactive position

what are some factors that change the reaction of an enzyme and how are they changed?

temperature and pH and they are changed by Denaturation

what is the role of enzymes in biological systems

they speed up reactions by lowering the activation energy

what is the relationship between enzyme structure and enzyme specificity

the active site is specific to the substrate

active site

groove or pocket where substrate binds

substrate

the thing that binds to the active site

list 4 ways that enzymes can lower activation energy

1. template for reactions to come together

2. bends bonds to get in the transition state

3. good microenvironment (pH)

4. bonding or place for them to come together

how does substrate concentration affect the rate of an enzyme controlled reaction

more substrates equals more reactions

what happens to the rate of an enzyme controlled reaction when the substrate level is high and remains high? and why does that happen

The enzyme activity would level out because there is a limited number of enzymes and you can only bond a limited number of substrates to a limited number of enzymes

what environmental conditions affect enzyme activity

temperature and pH

Small nonprotein molecules needed for enzyme reactions

cofactor

organic cofactors; vitamins

coenzymes

chemicals that inhibit enzyme activity

inhibitor

enzyme inhibitors that resemble the substrate and compete with the substrate for the active site

competitive inhibitors

enzyme inhibitors that bind to the enzyme at a site other than the active site and cause the enzyme to change shape

noncompetitive inhibitors

enzymes with two conformations one active and one inactive

allosteric enzymes

what happens during feedback inhibition

the regulation of a metabolic pathway by its end product, which inhibits an enzyme at an earlier point in the pathway

catabolism

releases energy by breaking down complex molecules to simple molecules

anabolism

consumes energy to synthesize a complex molecule from simpler molecules

energy

The ability to do work or cause change

child at top of slide

PE

child sliding down slide

KE

water behind dam

PE

Water turning turbines

KE

Glucose

PE

Food molecules

PE

according to the first law of thermodynamics if the total energy before a reaction is 500kcal then the total energy after the reaction must be

500kcal

According to the second law of thermodynamics if the total energy before an energy exchange is 500kcal then the amount of useful energy after the exchange is

less than 500kcal

does the second law of thermodynamic contradict the first law

the second law does not contradict because the first law refers to a closed system while the 2nd law refers to an open system

do highly ordered living organisms violate the second law of thermodynamics

no because we consume and release energy

Organisms cannot use heat energy to drive their energy requiring processes does this mean that the heat released by metabolism is of no use to them

no because it helps us maintain homeostasis

what are the 3 main kinds of work performed by or in cells

mechanical chemical and transport

Explain how ATP performs cellular work

ATP is hydrolyzed a phosphate breaks off and energy is released

When ATP is produced, energy is required. What is the source of this energy?

glucose

When ATP is broken energy is released How is this energy used

to do cellular work and it is used in endergonic reactions to build molecules

What is the delta G of a system that is in equilibrium

there is none

Can a system at equilibrium do work?

no: because you have nothing to do work with if you are at equilibrium

of the light energy reaching the earth from the sun the earth's plants are believed to convert less than 1% into the form of potential energy stored in the chemical bonds of food molecules. What happens to the rest of the energy

gets released as heat (lost)