chapter 8- metabolism

Question 1

how does the cell get energy and how does it use it

Answer 1

it extracts the energy stored in sugars and other energy containing molecules and applies energy to perform work

Question 2

what is metabolism

Answer 2

totality of an organisms chemical reactions/interactions between molecules within the cell

Question 3

how do metabolic pathways work

Answer 3

they begin with a specific molecule called substrate/reactant and end with product
each step is catalyzed by a specific enzyme

Question 4

what is a catabolic pathway and example

Answer 4

it releases energy by breaking down complex molecules into simpler compounds
cellular respiration

Question 5

what is an anabolic pathways

Answer 5

consumes energy to build complex molecules from simpler ones
synthesis of proteins

Question 6

what is bioenergetics

Answer 6

the study of how organisms manage their energy resources

Question 7

what is energy

Answer 7

capacity to cause change

Question 8

types of energy

Answer 8

kinetic (motion)
heat (movement)
potential (location)
chemical (available to release)

Question 9

what is thermodynamics

Answer 9

study of energy transformation

Question 10

difference between isolated and open system

Answer 10

isolated cant exchange energy or matter with environment
open can exchange with environment

Question 11

are organisms open or closed systems

Answer 11

open

Question 12

what is the first law of thermodynamics

Answer 12

energy cant be created or destroyed

Question 13

what is the second law of thermodynamics

Answer 13

energy transfer/transformation increases entropy of universe

Question 14

do spontaneous processes occur with or without energy

Answer 14

without energy

Question 15

if a process occurs without energy input what does it increase

Answer 15

entropy of universe

Question 16

what does the cell do when it has less ordered materials

Answer 16

creates ordered structures
requires energy input

Question 17

what does an organism do with ordered forms of matter and energy

Answer 17

replaces them with less ordered forms

Question 18

what is free energy

Answer 18

delta G
energy that can do work when the temperature and pressure are uniform (cell env.)

Question 19

what is the formula for free energy

Answer 19

delta G = delta H - (T)(delta S)
delta H: enthalpy
delta S: entropy
T is in kelvins

Question 20

what happens during a spontaneous process regarding free energy and stability

Answer 20

delta G must be negative
stability of system increases (moving towards eq)

Question 21

how is free energy related to stability

Answer 21

free energy is a measure of a system’s instability and its tendency to change to a more stable state

Question 22

what is the state of maximum stability

Answer 22

equilibrium

Question 23

what is an exergonic reaction

Answer 23

reaction with a net release of free energy
spontaneous

Question 24

what is an endergonic reaction

Answer 24

reaction that absorbs free energy from surrounding
nonspontaneous

Question 25

does metabolism ever reach equilibrium

Answer 25

no, open systems have a constant flow of energy and matter

Question 26

what are the three kinds of cellular work

Answer 26

chemical transport mechanical

Question 27

how do cells manage energy resources

Answer 27

energy coupling

Question 28

what is energy coupling

Answer 28

using an exergonic process to drive an endergonic one

Question 29

when atp is broken down what causes the release of energy

Answer 29

comes from the chemical change to a state of lower energy

Question 30

what kind of reaction is atp hydrolysis

Answer 30

exergonic and can be used to drive an endergonic reaction

Question 31

how does atp drive endergonic reactions

Answer 31

by phosphorylation

Question 32

what is the molecule receiving a phosphate now called

Answer 32

phosphorylated intermediate

Question 33

how is atp regenerated

Answer 33

using adp and energy released from catabolic/exergonic reactions

Question 34

what is a catalyst and example

Answer 34

chemical agent that speeds up reaction and is not consumed enzymes are catalysts

Question 35

what is the activation energy/free energy of activation

Answer 35

energy required to start a chemical reaction

Question 36

how do catalytic enzymes affect reactions

Answer 36

lower EA barrier dont affect change in free energy, only speed up reactions that would eventually occur

Question 37

when the enzyme binds to the substrate what is formed

Answer 37

enzyme-substrate complex

Question 38

what is an active site

Answer 38

region on enzyme where substrate binds

Question 39

what is the induced fit of a substrate

Answer 39

enzyme changing shape to better fit around substrate

Question 40

what does the induced fit do

Answer 40

brings chemical groups of active site into positions that enhance their ability to catalyze the reaction

Question 41

how does the active site lower the EA barrier

Answer 41

orients substrates correctly strains bonds in substrate provides favourable microenvironment covalently bonds to substrate

Question 42

enzyme activity is affected by

Answer 42

environmental factors (temp, pH) chemicals that affect that specific enzyme

Question 43

in which conditions does the enzyme work best

Answer 43

conditions that favour the most active shape specific pH

Question 44

what are cofactors

Answer 44

nonprotein enzyme helpers inorganic or organic (coenzyme) can be vitamins

Question 45

what is a competitive inhibitor

Answer 45

binds to active site competes with substrate

Question 46

what is a noncompetitive inhibitor

Answer 46

doesnt bind to active site but causes a change in shape making active site less effective

Question 47

inhibitors example

Answer 47

toxins poisons pesticides antibiotics

Question 48

what does a cell do to regulate metabolism

Answer 48

switches genes that code for specific enzymes on/off regulating enzyme activity

Question 49

what is allosteric regulation

Answer 49

either inhibiting or stimulating an enzyme's activity

Question 50

when does allosteric regulation happen

Answer 50

what a regulatory molecule binds to a protein at one site but affects the proteins functions at a different site

Question 51

how does the binding of an activator vs inhibitor affect the enzyme

Answer 51

the activator stabilizes the active form of the enzyme the inhibitor stabilizes the inactive form of the enzyme

Question 52

what is cooperativity

Answer 52

form of allosteric regulation that can amplify the enzymes activity

Question 53

what happens in feedback inhibition

Answer 53

the end product of a metabolic pathway shuts down the pathway

Question 54

are enzymes located in specific areas of cell

Answer 54

yes enzymes that act as structural components are in membranes enzymes for cellular respiration are in the mitochondria