metabolism

Question 1

what is metabolism

Answer 1

all chemical reactions in an organism

Question 2

what is a metabolic pathway?

Answer 2

starts with a molecule that is then altered in a series of steps and ends in a product, with each step being catalyzed by an enzyme

Question 3

what is a catabolic pathway

Answer 3

degradative process, breaks down complex molecules, releases energy (downhill)

Question 4

what is a anabolic pathway

Answer 4

biosynthetic, build molecules, uses energy (uphill)

Question 5

what is an example of kinetic energy

Answer 5

thermal energy

Question 6

what is thermal energy

Answer 6

the movement of atoms/molecules

Question 7

how is thermal energy transferred

Answer 7

as heat

Question 8

what is an example of potential energy

Answer 8

chemical energy

Question 9

what type of system are cells

Answer 9

open sestems

Question 10

what is an open system

Answer 10

both matter and energy are exchanged

Question 11

what is an isolated system

Answer 11

neither energy nor matter are exchanged

Question 12

what is a closed system

Answer 12

only energy is exchanged

Question 13

what is the first law of thermodynamics

Answer 13

energy is conserved and constant

Question 14

what does an open system for cells mean

Answer 14

constant flow of energy, never at equilibrium, never stops working

Question 15

what is the second law of thermodynamics

Answer 15

every transformation increases the entropy of the universe

Question 16

what is entropy

Answer 16

measure of disorder/randomness

Question 17

what does an increase in entropy mean

Answer 17

spontaneous

Question 18

what does a decrease in entropy mean

Answer 18

non spontaneous

Question 19

what is gibbs free energy

Answer 19

the portion of systems energy that can perform work at constant pressure and temperature

Question 20

what does negative gibbs mean

Answer 20

spontaneous, exergonic, energy lost, final state more stable

Question 21

what does positive mean

Answer 21

nonspontaneous, endergonic, enrgy gained

Question 22

what is exergonic and an example

Answer 22

release of free energy, respiration

Question 23

what is endergonic and an example

Answer 23

absorbs free energy, photosynthesis

Question 24

what three types of work does ATP power

Answer 24

chemical, mechanical, and transport

Question 25

what is energy coupling

Answer 25

the use of an exergonic process to drive and endergonic one

Question 26

breakdown of ATP reaction

Answer 26

ATP + H2O ----> ADP + P + energy

Question 27

what makes ATP like a compressed spring?

Answer 27

three phosphate groups with a negative charge = mutual repulsion, very unstable

Question 28

regeneration of atp reaction

Answer 28

ADP + P + energy ----> ATP + H2O

Question 29

what is an enzyme and what does it do

Answer 29

catalyst, speeds up a reaction without being consumed

Question 30

what is activation energy

Answer 30

barrier, energy required to initiate a reaction

Question 31

what do enzymes do to activation energy

Answer 31

lowers it

Question 32

how does an enzyme lower activation energy

Answer 32

orientation, stretch substrate, active site (microenvironment), amino acids

Question 33

how does an enzyme react (general reaction)

Answer 33

enzyme + substrate ---> enzyme-substrate complex ----> enzyme + product

Question 34

how do enzymes recognize their specific substrate

Answer 34

3D shape, induced fit

Question 35

what are optimal conditions for an enzyme

Answer 35

conditions that favour the most active shape for an enzyme

Question 36

what are two factors considered for optimal conditions

Answer 36

temperature and pH

Question 37

what are cofactors

Answer 37

nonprotein helpers for catalytic activity

Question 38

what do competitive inhibitors do and how

Answer 38

lower productivity by blocking substrates from entering active sites (bind to the active site)

Question 39

what do non competitive inhibitors do and how

Answer 39

lower productivity by binding to another part of the enzyme changing its shape

Question 40

what are enzyme inhibitors used for

Answer 40

regulation of metabolism

Question 41

what is the difference between irreversible and reversible inhibitors

Answer 41

irreversible = covalent bonds, reversible = weak interactions

Question 42

what is allosteric regulation

Answer 42

protein function at one site is affected by the binding of a regulatory molecule to a separate site

Question 43

what does allosteric regulation result in (2)

Answer 43

inhibition or stimulation

Question 44

what does an activator do

Answer 44

stabilizes the active form

Question 45

what does an inhibitor do

Answer 45

stabilizes the inactive form

Question 46

are all active sites of all subunits affected by a single molecule bonding

Answer 46

yes

Question 47

what does cooperativity do

Answer 47

increases response of enzymes to substrates

Question 48

what happens in cooperativity

Answer 48

a substrate binds to an active site in a multisubunit enzyme, changes the shape of all subunits and increaseing acitivty

Question 49

what is feedback inhibition

Answer 49

metabolic pathway halted by inhibitory binding of an end product to enzyme that acts early in the pathway