Ch. 6 Metabolism

Question 1

what is energy?

Answer 1

the capacity to do work

Question 2

forms of energy

Answer 2

• potential energy

- kinetic energy

Question 3

potential energy

Answer 3

stored energy

Question 4

kinetic energy

Answer 4

energy of motion

Question 5

where does energy come from?

Answer 5

• main source of energy on Earth: the sun

- energy is captured and stored in organic molecules

Question 6

how do cells use energy

Answer 6

• chemical work
• mechanical work
• electrochemical work
• thermal work/ heat

Question 7

First Law of Thermodynamics

Answer 7

energy cannot be created nor destroyed

• the total amount of energy before and after every conversion always remains the same
• amount of energy in the universe remains the same

Question 8

One- way flow of energy

Answer 8

the sun is the primary source of energy for life

• producers: trap energy from the sun and convert it to chemical energy
• all organisms use the energy stored in organic compounds to do work

Question 9

Law of Conservation of Mass

Answer 9

matter cannot be created nor destroyed

~ matter only changes in form

Question 10

Second Law of Thermodynamics

Answer 10

energy is always flowing from high energy forms to lower energy forms

• energy tends to disperse spontaneously
• *no conversion is 100% efficient, some energy is always lost as heat to the environment**

Question 11

entropy

Answer 11

measure of disorder/randomness/dispersion of energy in a system

Question 12

exergonic reaction

Answer 12

energy is released

• products have less energy that starting substance
• to retrieve energy stored in bonds of organic compounds

Question 13

endergonic reaction

Answer 13

energy input required

• products have more energy than starting substance
• to store energy in bonds of organic compounds

Question 14

ATP’s role

Answer 14

to carry energy

*made up of adenine, ribose, and phosphates
1 phosphate: adenosine monophosphate
2 phosphates: adenosine diphosphate
3 phosphates : adenosine triphosphate

Question 15

phosphorylation

Answer 15

transfer of a phosphate from one molecule to another
-when ATP gives up a phosphate group: ADP is formed
-ATP can reform when ADP binds to another phosphate group
phosphorylation processes help drive metabolic reactions (both exergonic and endergonic)

Question 16

oxidative phosphorylation

Answer 16

production of ATP during cellular respiration where there’s involvement of oxidized molecules in the process

Question 17

chemiosmosis

Answer 17

• used during the light reaction of photosynthesis to harness energy of sunlight
• generate ATP from catabolism of glucose

Question 18

anabolic reactions

Answer 18

small molecules are assembled into larger ones’

• also called ‘biosynthetic
• products have more stored energy

Question 19

catabolic reactions

Answer 19

large molecules are broken down into small ones

• also called ‘degradative’
• products have less stored energy

Question 20

metabolic pathways

Answer 20

• photosynthesis is biosynthetic

- cellular respiration is degradative

Question 21

Activation energy

Answer 21

amount of energy required to cause molecular bonds to break

Question 22

enzymes and activation energy

Answer 22

enzyme reduce amount of energy (activation) necessary to start the reaction
-proteins that acts at a catalytic molecules

Question 23

features of enzymes (1)

Answer 23

enzymes do not make anything happen that could not happen on its own– just speed it up

Question 24

features of enzymes (2)

Answer 24

reactions do not alter or use up enzyme molecules

Question 25

features of enzymes (3)

Answer 25

the same enzyme usually works for the forward and backwards of a reaction

Question 26

features of enzymes (4)

Answer 26

each type of enzyme recognizes and binds to only certain substrates

Question 27

enzyme/substrate complex

Answer 27

• substrates binds enzyme at the active site (lock and key)

- enzyme is then released to be used again if needed

Question 28

factors that affect enzyme reactiosn

Answer 28

• temperature (internal and external)
• pH value (external and internal)
• enzyme synthesis
• presence of regulatory on the enzyme
• cofactors- make them more reactive
• coenzymes-transfer protons and electrons
• ions-effect chemical charge can slow or quicken an enzyme

Question 29

types of enzyme inhibitors

Answer 29

• allosteric inhibitors

- allosteric activators

Question 30

allosteric inhibitors

Answer 30

modify the active site of the enzyme so that substrate binding is reduce/prevented

Question 31

allosteric activators

Answer 31

modify the active site of the enzyme so that affinity for the substrate increases

Question 32

what do statins do?

Answer 32

• class of drugs that reduce cholesterol levels
• compounds are inhibitors of the enzyme HMG-CoA reductase, the enzyme that synthesizes cholesterol from lipids in the body

Question 33

what does acetaminophen do?

Answer 33

also called “Tylenol”

• is an inhibitor of the enzyme: cyclooxygenase
• effective in providing relief from fever and inflammation

Question 34

cofactors

Answer 34

inorganic ion like iron (Fe++), magnesium (Mg++), and zinc (Zn++)

• helps enzymes become catalysts*
• one example of an enzyme that requires a metal ion as a cofactor is the enzyme DNA polymerase

Question 35

REDOX reactions

Answer 35

most energy pathways are a combination of reduction and oxidation reactions

• oxidation and reduction usually occur together
• shift of an electron from one compound to another removes some potential energy from first compound (oxidized) and increase the potential energy for the second compound (reduced)

Question 36

electron carriers

Answer 36

• bind, carry high energy between compounds
  
  • must derive from the B vitamin group
• these compounds can be easily reduced or oxidized
• NAD: nicotinamide adenine dinucleotide
• NAD+: oxidized
• NADH: reduced

Question 37

biolumeniscence

Answer 37

enzyme-mediated reactions that release energy as fluorescent light
-luciferase is the enzyme that interact with an oxidized substance luciferin in order to produce the byproduct: oxyluciferin
the chemical reaction producing oxylucerfin produces light