CHAPTER 6 Flashcards
(94 cards)
1
Q
When a reaction is exergonic
A
- free energy change is neg
- its spontaneous
- doesn’t need energy to process
- entropy increases
2
Q
Why do cells use ATP hydrolysis
A
to drive endergonic reaction
3
Q
kinetic energy
A
mvmnt
4
Q
potential energy
A
energy held by an object because of its position relative to other objects
5
Q
chemical potential energy
A
energy stored in bonds between atoms
6
Q
List the types of energy
A
- light
- heat
- mechanical
- chemical potential
- electrical/gradient ion
7
Q
how many laws of thermodynamics is there
A
2
8
Q
what is the first law of thermodynamics
A
energy can not be created or destroyed but transferred from one place to another ex chemical energy to heat
9
Q
second law of thermodynamics
A
relation between heat and other forms of energy (such as mechanical, electrical, or chemical energy), and, by extension, of the relationships between all forms of energy.
10
Q
entropy
A
degree of disorder
11
Q
what happens when a physical system becomes distorted
A
entropy increases
12
Q
what happens when energy becomes evenly distributed
A
that energy is less able to promote change or do work
13
Q
what is needed for all cellular process
A
energy
14
Q
useable energy
A
used to promote change or do work
15
Q
unusable energy
A
not able to do work
16
Q
what are the factors of total energy
A
usable+unusable
17
Q
enthalpy
A
total energy of a system
18
Q
exergonic
A
spontaneous (neg)
19
Q
endergonic
A
not spontaneous (pos)
20
Q
phosphorylation
A
attachment of a phosphate to a molecule.
21
Q
what determines the fate of a chemical reaction
A
direction , rate
22
Q
how long do chemical reactions go on for
A
until equilibrium
23
Q
what happens after chemical equilibrium is met
A
rate of formation of products equals rate of formation of reactants.
24
Q
what do enzymes increase
A
the rate of chemical reactions
25
what is the most common catalyst
enzymes
26
Activation energy
initial input of energy in a chemical reaction that allows the molecules to get close enough to cause a rearrangement of bonds.
27
transition state
chemical reaction, a state in which the original bonds have stretched to their limit; once this state is reached, the reaction can proceed to the formation of products.
28
How do enzymes lower the activation energy barrier of chemical reactions?
- straining reactants
| - positioning reactants close together
29
Active site
The location in an enzyme where a chemical reaction takes place.
30
substrate
1. The reactant molecules and/or ions that bind to an enzyme at the active site and participate in a chemical reaction. 2. The organic compounds such as soil or rotting wood that fungi use as food.
31
what does the binding between enzyme and substrate produce
enzyme-substrate complex
32
what is a key feature of nearly all enzymes
ability to bind their substrates with a high degree of specificity
33
induced fit
substrate binds to an enzyme and the enzyme undergoes a conformational change that causes the substrate to bind more tightly to the enzyme.
33
induced fit
substrate binds to an enzyme and the enzyme undergoes a conformational change that causes the substrate to bind more tightly to the enzyme.
34
Affinity
degree of attraction between an enzyme and its substrate(s).
35
Vmax
The maximal velocity of an enzyme-catalyzed reaction.
36
kM
substrate concentration at which an enzyme-catalyzed reaction is half of its maximal value.
37
competitive inhibitor
A molecule that binds to the active site of an enzyme and inhibits the ability of the substrate to bind.
38
noncompetitive inhibitor
A molecule that binds to an enzyme at a location that is outside the active site and inhibits the enzyme’s function.
39
allosteric site
A site on an enzyme where a molecule can bind noncovalently and affect the function of the active site.
40
how do most enzymes maximally function
in a narrow range of temperature and pH
41
why do enzymes sometimes need nonprotein molecules
to function, and other factors, including temperature and pH, can affect the proper functioning of enzyme
42
The main effect of enzymes on a chemical reaction is to
lower the activation energy and thereby increase the rate of the reaction.
43
An inhibitor raises the KM for an enzyme but has no effect on the Vmax. This inhibitor probably binds to
the active site
44
metabolic pathway
series of chemical reactions in which each step is catalyzed by a specific enzyme.
45
catabolic reaction
A metabolic pathway in which a molecule is broken down into smaller components, usually releasing energy.
46
anabolic reaction
A metabolic pathway that involves the synthesis of larger molecules from smaller precursor molecules. Such reactions usually require an input of energy.
47
are anabolic reactions endergonic or exergonic
endergonic
48
are catabolic reactions endergonic or exergonic
exergonic
49
what do catabolic reactions result in
breakdown of larger molecules into smaller ones
50
name one reason to breakdown macromolecules
to recycle their organic molecules which then are used as building blocks to construct new molecules and macromolecules
51
oxidation
A process that involves the removal of electrons; occurs during the breakdown of small organic molecules.
52
reduction
A process that involves the addition of electrons to an atom or a molecule.
53
redox reaction
a type of reaction in which an electron that is removed during the oxidation of an atom or a molecule is transferred to another atom or molecule, which becomes reduced; short for reduction-oxidation reaction.
54
Ae-+B--->A+Be-
| which letter is oxidized and which letter is reduced
A: oxidized
B: reduced
55
nicotinamide adenine dinucleotide (NAD+)
A dinucleotide that functions as an energy intermediate molecule. It combines with two electrons and H+ to form NADH.
56
what level does the regulation of catabolic and anabolic occur at
genetic, cellular, biochemical
57
gene regulation
Enzymes are proteins that are encoded by genes.
58
cell signaling pathways
Cells integrate signals from their environment and adjust their metabolic pathways to adapt to those signals
59
biochemical
noncovalent binding of a molecule to an enzyme directly regulates the enzyme’s function.
60
feedback inhibition
A form of regulation in which the product of a metabolic pathway inhibits an enzyme that acts early in the pathway, thus preventing the overaccumulation of the product.
61
cellular respiration
A process by which living cells obtain energy from organic molecules and release waste products
62
aerobic respiration
A type of cellular respiration in which O2 is consumed and CO2 is released.
63
What are the different types of organic molecules used as energy sources to drive aerobic respiration
carbohydrates, proteins, and fats,
64
what is metabolism the sum of
chemical reactions in a living organism.
65
cristae
Projections of the highly invaginated inner membrane of a mitochondrion.
66
A general reason for the catabolism of organic molecules is
- the recycling of building blocks.
| - the synthesis of energy intermediates, such as ATP.
67
The breakdown of glucose commonly occurs in which of the following orders
glycolysis, the breakdown of pyruvate, the citric acid cycle, oxidative phosphorylation
68
how many steps does glycosides have
10
69
how many phases can these steps be grouped into
3
70
what are the three phases
energy investment, cleavage, energy liberation
71
energy investment phase
The first phase (steps 1–3) involves an energy investment. Two ATP molecules are hydrolyzed, and the phosphates from those ATP molecules are transferred to glucose, which is converted to fructose-1,6-bisphosphate. The energy investment phase raises the free energy of glucose, thereby allowing later reactions to be exergonic.
72
cleavage phase
During steps 4 and 5, a six-carbon molecule is cleaved into two molecules of glyceraldehyde-3-phosphate.
73
energy liberation phase
The end result of steps 6–10 is to produce four ATP, two NADH, and two molecules of pyruvate. Because two molecules of ATP are used in the energy investment phase, the net yield is two molecules of ATP
74
how do cells control glycosis
availability of substrates, such as glucose, and by feedback inhibition
75
when does feedback inhibition occur
cell has a sufficient amount of ATP,
76
what happens at high concentrations
ATP binds reversibly to an allosteric site in phophofru.. this causes a conformational change that renders the enzyme functionionally inactive
77
During glycolysis, ATP is used during the __________ phase, and ATP is synthesized during the __________ phase.
energy investment, energy liberation
78
Which of the following is not a product of glycolysis?
CO2
79
products of glycosides
ATP, NADH, pyruvate
80
In eukaryotes what does glycosides produce
pyruvate in the cytosol.. then pyruvate is transported into the mitochondria
81
what happens once the pyruvate is in the mitochondrial matrix
pyruvate molecules are broken down (oxidized) by an enzyme complex called pyruvate dehydrogenase
82
What are the products of the breakdown of pyruvate
NADH, acetyl group (attached to CoA), acetyl group (attached to CoA)
83
citric acid cycle
A cycle that results in the breakdown of carbohydrates to CO2; also known as the Krebs cycle.
84
During the citric acid cycle, what happens to carbon?
- Organic carbon is released as inorganic carbon dioxide
| - Carbon is oxidized to make NADH and FADH2.
85
oxidative phosphorylation
A process during which NADH and FADH2 are oxidized to make more ATP via the phosphorylation of ADP.
86
electron transport chain (ETC)
A group of protein complexes and small organic molecules within the inner membranes of mitochondria and chloroplasts and the plasma membrane of prokaryotes. Electrons are passed from one component to the next via a series of redox reactions and produce an H+ electrochemical gradient.
87
H+ electrochemical gradient
A transmembrane gradient for H+ composed of both a membrane potential and a concentration difference for H+ across a membrane.
88
H+ electrochemical gradient
A transmembrane gradient for H+ composed of both a membrane potential and a concentration difference for H+ across a membrane.
89
The electrons that travel down the electron transport chain come from
NADH or FADH2
90
The source of energy that directly drives the synthesis of ATP during oxidative phosphorylation is
the H+ gradient.
91
The spinning of the γ subunit of ATP synthase is caused by
- the hydrolysis of ATP.
| - the movement of H+ through ATP synthase.
92
Compared with oxidative phosphorylation in mitochondria, anaerobic respiration in bacteria differs in that
something other than O2 acts as a final electron acceptor of the ETC.
93
Compared with oxidative phosphorylation in mitochondria, anaerobic respiration in bacteria differs in that
something other than O2 acts as a final electron acceptor of the ETC.
