Unit 3 Flashcards
(163 cards)
1
Q
What is metabolism?
A
Metabolism is all of the chemical reactions in an organism.
2
Q
What are metabolic pathways?
A
Metabolic pathways are series of chemical reactions that either build complex molecules or break down complex molecules.
3
Q
What are the two types of metabolic pathways?
A
The two types of metabolic pathways are catabolic pathways and anabolic pathways.
4
Q
What are catabolic pathways?
A
Catabolic pathways are pathways that release energy breaking down complex molecules into simpler compounds.
5
Q
What are anabolic pathways?
A
Anabolic pathways are pathways that consume energy to build complicated molecules for simpler compounds.
6
Q
What is energy?
A
Energy is the ability to do work.
7
Q
Why do organisms need energy?
A
Organisms need energy to survive and function.
8
Q
What will happen to an organism if there is a loss in energy flow?
A
If an organism has a loss in energy flow it results in death.
9
Q
What is kinetic energy?
A
Kinetic energy is energy associated with motion.
10
Q
What is thermal energy?
A
Thermal energy is energy associated with the movement of atoms or molecules.
11
Q
What is potential energy?
A
Potential energy is stored energy.
12
Q
What is chemical energy?
A
Chemical energy is potential energy available for release in a chemical reaction.
13
Q
What is thermodynamics?
A
Thermodynamics is the study of energy transformations in matter.
14
Q
What is the 1st law of thermodynamics?
A
The 1st law of thermodynamics is energy cannot be created or destroyed but energy can be transferred or transformed.
15
Q
What is the 2nd law of thermodynamics?
A
The second law of thermodynamics is that energy transformation increases the entropy (disorder) of the universe. During energy transfers or transformations, some energy is unusable and often lost as heat.
16
Q
What is the concept of free energy used for?
A
The concept of free energy is used to determine the likelihood of reactions in organisms or if the reactions are energetically. It determines whether a reactions occurs spontaneously.
17
Q
Based on free energy, what are the two things chemical reactions be classified as?
A
The two things chemical reactions can be classified as are exergonic reactions or endergonic reactions.
18
Q
What are exergonic reactions?
A
Exergonic reactions are reactions that release energy.
(reaction is spontaneous)
ex. cellular respiration
19
Q
What are endergonic reactions?
A
Endergonic reactions are reactions that absorb energy.
(reaction is not spontaneous and absorbs free energy)
ex. photosynthesis
20
Q
How does material flow in living cells?
A
Living cells have a constant flow of materials in and out of the membrane, and are not at equilibrium.
21
Q
What are the three kinds of work cells perform?
A
The three types of work that cells perform are mechanical, transport, and chemical.
22
Q
What is mechanical work done by cells?
A
Mechanical work done by cells is movement.
23
Q
What is transport work done by cells?
A
Transport work done by cells is pumping substances across membranes against spontaneous movement.
24
Q
What is chemical work done by cells?
A
Chemical work done by cells is synthesis of molecules.
25
What is adenosine triphosphate?
Also known as ATP, adenosine triphosphate is a molecule that organisms use as a source of energy to perform work.
26
How does ATP power cellular work?
ATP couples exergonic reactions to endergonic reactions to power cellular work.
27
What is phosphorylation?
Phosphorylation is when the released phosphate moves to another molecule to give energy .
28
How can ATP be regenerated?
ADP can be regenerated to ATP via the ATP cycle.
29
What do enzymes help do in cells?
Enzymes help cells to speed up reactions and break things down.
30
What are enzymes?
Enzymes are macromolecules that catalyze (speed up) reactions by lowering the activation energy. They are a type of protein and are not consumes by the reaction.
31
What do enzymes act on?
Enzymes act on a reactant called a substrate.
32
What is an active site in an enzyme structure?
An active site is an area for substrates to bind.
33
What is an induced fit in the enzyme structure?
An induced fit is when an enzyme will change the shape of their active site to allow the substrate to bind better.
34
What happens during enzyme catabolism?
During enzyme catabolism an enzyme helps break down complex molecules.
35
What happens during enzyme anabolism?
During enzyme anabolism an enzyme helps build complex molecules.
36
What can affect the efficiency of enzymes?
The efficiency of enzymes can be affected by temperature, pH, and chemicals.
37
What does a change in shape mean for enzymes?
A change in shape means a change in function for enzymes.
38
What are optimal conditions for enzymes?
Optimal conditions are the conditions (temperature & pH) that allow enzymes to function optimally and at their best.
39
What are enzyme cofactors?
Cofactors are non protein molecules that assist enzyme function. They can bound loosely or tightly.
40
What is a holoenzyme?
A holoenzyme is an enzyme with the cofactor attached.
41
What are coenzymes?
Coenzymes are organic cofactors.
42
What are enzyme inhibitors?
Enzyme inhibitors reduce the activity of specific enzymes and they can be permanent or reversible.
43
What does it mean when an enzyme inhibitor is permanent?
A permanent inhibitor binds with covalent bonds.
44
What does it mean when an enzyme inhibitor is reversible?
A reversible inhibitor binds with weak interactions.
45
What are competitive inhibitors?
Competitive inhibitors reduce enzyme activity by blocking substrate from binding to the active site.
46
How can competitive inhibitors be reversed?
Competitive inhibitors can be revered with increased substrate concentrations.
47
What is a noncompetitive inhibitor?
Noncompetitive inhibitors bind to an area other than the active site (allosteric site) which changes the shape of the active site preventing substrates from binding.
48
How does a cell regulate its metabolic pathways?
A cell must be able to regulate its metabolic pathways by controlling where and when enzymes are active and switch genes that code for enzymes off or on.
49
What are the two binding sites that allosteric enzymes have?
Allosteric enzymes have two binding sites that are 1 active site and 1 allosteric site (regulatory site; site other than the active site).
50
What is allosteric regulation?
Allosteric regulation is when molecules bind (noncovalent interactions) to an allosteric site which changes the shape and function of the active site. This may result in inhabitation (by an inhibitor) or stimulation (by an activator) of enzymes activity.
51
What is an allosteric activator?
An allosteric activator is an allosteric substance that bind to an allosteric site and stabilizes the shape of the enzyme so that the active site remains open.
52
What is an allosteric inhibitor?
An allosteric inhibitor is an allosteric substance that binds to an allosteric site and stabiles the enzyme shape so that the active sites are closed (inactive form).
53
What is cooperativity?
Cooperativity is when an allosteric substrate binds to one active site (on an enzyme with more than one active site) which stabilizes the active form. This is considered allosteric regulation since binding at one site changes to shape of other sites.
54
What is photosynthesis?
Photosynthesis is the conversion of light energy to chemical energy.
55
What are autotrophs?
Autotrophs are organisms that produce their own food (organic molecules) from simple substances in their surroundings.
56
What are heterotrophs?
Heterotrophs are organisms unable to make their own food so they live off of other organisms.
57
Where did photosynthesis first evolve?
Photosynthesis first evolved in prokaryotic organisms.
58
What is cyanobacteria?
Cyanobacteria is early prokaryotes capable of photosynthesis and oxygenated the atmosphere of early earth.
59
Where did the foundation of eukaryotic photosynthesis come from?
Prokaryotic photosynthetic pathways were the foundation of eukaryotic photosynthesis.
60
What is the primary location of photosynthesis is most plants?
Leaves are the primary location of photosynthesis in most plants.
61
What is a chloroplast?
A chloroplast is the organelle for the location photosynthesis.
62
Where are chloroplast found?
Chloroplast are found in the mesophyll.
63
What is the mesophyll?
The mesophyll is the cell that makes up the interior tissue of the leaf.
64
What are stomata?
Stomata are pores in leaves that allow CO2 in and O2 out.
65
What surrounds chloroplasts?
Chloroplasts are surrounded by a double membrane?
66
What is stroma?
Stroma is aqueous internal fluid.
67
What forms grana?
Thylakoids form stacks known as grana.
68
What is chlorophyll?
Chlorophyll is green pigment in the thylakoid membrane.
69
How does photosynthesis affect H2O?
Photosynthesis splits H2O into H and O.
70
What is a redox reaction?
A redox reaction is a reaction involving complete or partial transfer of one or more electrons from one reactant to another.
71
In photosynthesis how is a sugar formed?
In photosynthesis the electrons are transferred with H+ (from split H2O) to CO2 reducing it to sugar.
72
What is oxidation?
Oxidation is loss of electrons.
73
What is reduction?
Reduction is gain of electrons.
74
What are the two stages of photosynthesis?
The two stages of photosynthesis are the light reaction and the Calvin cycle.
75
What is light defined as?
Light is electromagnetic energy.
76
What is light made up of?
Light is made up of particles of energy called photons.
77
How does light travel?
Light travels in waves.
78
What is wavelength?
Wavelength is the distance from the crest of one wave to the crest of the next.
79
What is the electromagnetic spectrum?
The electromagnetic spectrum is the entire range of wavelengths.
80
What is the range of visible light wavelengths?
Visible light comes in wavelengths of 320 nm to 750 nm.
81
What do short wavelengths indicate?
Short wavelengths have higher energy.
82
What do long wavelengths indicate?
Long wavelengths indicate lower energy.
83
What can happen when light interacts with matter?
Light can be reflected, transmitted, or absorbed when it interacts with matter.
84
What is chlorophyll a?
Chlorophyll a is the primary pigment. It is involved in the light reactions and is a blue/green pigment.
85
What is chlorophyll b?
Chlorophyll b is an accessory pigment and is a yellow/green pigment.
86
What are carotenoids?
Carotenoids broaden the spectrum of colors that drive photosynthesis and are yellow/orange pigment.
87
What is photoprotection?
Photoprotection is when carotenoids absorb and dissipate excessive light energy that could damage chlorophyll or interact with oxygen.
88
Where do light reactions occur?
Light reactions occur in the thylakoid membrane in the photosynthesis.
89
What does photosynthesis do?
Photosynthesis convers solar energy to chemical energy.
90
What are the two forms of chemical energy?
The two forms of chemical energy are NADPH and ATP.
91
How do cells accomplish energy conversion?
Cells accomplish this conversion by using light energy (photons) to excite electrons.
92
How is light important to chlorophyll?
Chlorophyll absorbs a photon of light, which excites the electrons. This causes the electron to become unstable and fall back to ground state which results in energy being released as heat and emits photons as fluorescence.
93
What are photosystems?
Photosystems are reaction center and light capturing complexes.
94
What is a reaction center?
A reaction center is a complex of proteins associated with chlorophyll a and an electron acceptor.
95
What are light capturing complexes?
Light capturing complexes are pigments associated with proteins.
96
What are the two photosystems in the thylakoid membrane?
The two photosystems in the thylakoid membrane are photosystem 2 and photosystem 1.
97
What does the fall of electrons do for ATP?
The fall of electrons from PSII to PSI provides energy to form ATP.
98
What kind of energy is the H+ gradient?
The H+ gradient is a form of potential energy.
99
What does the ATP synthase do?
ATP synthase couples the diffusion of H+ to the formation of ATP.
100
What are the inputs of light reactions?
The inputs of light reactions are H20, ADP, and NADP+.
101
What are the outputs of light reactions?
The outputs of light reactions are O2, ATP, and NADPH.
102
Why is the splitting of water important in light reactions?
The splitting of water helps form a proton gradient across the membrane, which later will be used for fueling the production of ATP as the protons move down their concentration gradient through ATP synthase.
103
Where are chlorophyll and the ETC located?
Chlorophyll and the ETC is located in the thylakoid membrane.
104
How are the products produced in the light reactions used in the Calvin cycle?
The products of light reactions help fuel the Calvin cycle.
105
What is the Calvin cycle?
The Calvin cycle is cyclic electron flow. It uses NADPH, ATP, and CO2. It also produces a 3 - C sugar G3P.
106
What does the Calvin cycle use to reduce CO2 to sugar (G3P)?
The Calvin cycle uses ATP and NADPH to reduce CO2 to sugar (G3P).
107
What are the three phases of the Calvin cycle?
The three phases of the Calvin cycle are carbon fixation, reduction, and regeneration of ATP.
108
What happens in phase one of the Calvin cycle (carbon fixation) ?
In carbon fixation CO2 is incorporated into the Calvin cycle one at a time. Each CO2 attaches to a molecule of RuBP, which is then catalyzed by the enzyme rubisco. This forms 3 - phosphoglycerate.
109
What happens in phase two of the Calvin cycle (reduction)?
In reduction each molecule of 3 - phosphoglycerate is phosphorylated by ATP (using 6 total).
110
What happens in phase three of the Calvin cycle (regeneration of RuBP)?
In the regeneration of RuBP 5 molecules are used to regenerate 3 molecules of RuBP, which means the cycle is now ready to take in CO2 again.
111
What are the inputs of the Calvin cycle?
The inputs of the Calvin cycle are 3 CO2, 9 ATP, and 6 NADPH.
112
What are the outputs of the Calvin cycle?
The outputs of the Calvin cycle are 1 G3P, 9 ADP, and 6 NADPH+.
113
What is photorespiration?
Photorespiration is when on very hot days plants close their stomata to stop water loss. This causes less CO2 to be present and more O2. Rubisco binds to O2 and uses ATP, which produces CO2 but no sugar. This is bad for plants.
114
What do C4 plants do?
C4 plants use spatial separation of steps. They partially close their stomata to conserve water.
ex. corn, grasses, sugarcane
115
What do CAM plants do?
CAM plants open their stomata at night and close during the night. During the day light reactions occur.
ex. pineapples, cacti, succulents
116
What is the name of the enzyme that catalyzes the first step of the Calvin cycle?
The enzyme that catalyzes the first step of the Calvin cycle is Rubisco.
117
For every 3 molecules of CO2 that enter the Calvin cycle how many G3P are formed?
For every 3 molecules of CO2 that enter the Calvin cycle, 6 G3P are formed.
118
How many of the G3P that come from the Calvin cycle are net, and how many are used to regenerate RuBP?
Only 1 is net, the other 5 G3P molecules are recycled to regenerate RuBP.
119
Why is the process of photorespiration harmful to plants?
The process of photorespiration is harmful to plants because O2 will bind to Rubisco.
120
What is the major source of fuel for animals?
Starch is the major source of fuel for animals.
121
What do cells harvest in organic molecules to generate ATP?
Cells harvest chemical energy stored in organic molecules and use it to generate ATP.
122
What does starch break down into?
Starch breaks down into glucose.
123
What releases energy to be used in ATP synthase?
The oxidation of glucose transfers an electron to a lower energy state, releasing energy to be used in ATP synthase.
124
During cellular respiration, what is the "downhill" exergonic path?
The "downhill" exergonic path is glucose > NADPH > ETC > oxygen.
125
What is an electron transport chain (ETC)?
The ETC is a sequence of membrane proteins that shuttle electrons down a series of redox reactions.
126
What are the three stages of cellular respiration?
The three stages of cellular respiration are glycolysis, pyruvate oxidation and the Citric Acid cycle, and oxidative phosphorylation (ETC & chemiosmosis).
127
What is the process of glycolysis?
Glycolysis is the starting point of cellular respiration and it occurs in the cytosol. It splits glucose (6C) into pyruvates (3C).
128
What are the two stages of glycolysis?
The two stages of glycolysis are the energy investment stage, and the energy payoff stage.
129
What happens during the energy investment stage in glycolysis?
During the energy investment stage the cell uses ATP to phosphorylate compounds of glucose.
130
What happens during the energy payoff stage in glycolysis?
During the energy payoff stage energy is produced y substrate level phosphorylation; the net energy yield per 1 glucose: 2 ATP & 2 NADPH.
131
What is the net outcome of glycolysis?
The net outcome of glycolysis is 2 pyruvate+2 H20, 2 ATP, and 2 NADH+2 H+.
132
What is the net production of ATP in glycolysis?
The net production of ATP in glycolysis is 2 ATP.
133
What happens during pyruvate oxidation?
Pyruvate is oxidized into acetyl CoA.
134
What happens during the citric acid cycle?
The citric acid cycle turns acetyl CoA into citrate. This releases CO2. ATP is then synthesized. Electrons are transferred to NADH and FADH2.
135
What is the citric acid cycle also known as?
The citric acid cycle is also known as the Krebs cycle.
136
What are the inputs of the citric acid cycle?
The input of the citric acid cycle are 2 acetyl CoA.
137
What are the outputs of the citric acid cycle?
The outputs of the citric acid cycle are 2 ATP, 6 NADH, 4 CO2, and 2 FADH2.
138
Where does the citric acid occur?
The citric acid occurs in the mitochondrial matrix.
139
What does oxidative phosphorylation consists of?
Oxidative phosphorylation consists of electron transport chain and chemiosmosis.
140
Where is the ETC for cellular respiration located?
The ETC for cellular respiration is located in the inner membrane of the mitochondria.
141
What is the ETC for cellular respiration a collection of?
The ETC is a collection of proteins.
142
What happens to proteins in the ETC (cellular respiration) as electrons "fall"?
As the electrons fall proteins alternate between a reduced (accepts e-) and oxidized (donates e-) state.
143
What does the cristae do?
The cristae increases the surface area for reactions to occur. It helps manage the release of energy by creating several small steps for fall electrons.
144
What is the final electron acceptor?
The final electron acceptor is oxygen. Each oxygen pairs with 2 H+ ad 2 e- to form H2O.
145
What is ATP synthase?
ATP synthase is the enzyme that makes ATP from ADP + P. It uses energy from the H+ gradient across the membrane.
146
What happens during chemiosmosis?
H+ ions flow down their gradient through ATP synthase. ATP synthase acts like a rotor (when H+ bind the rotor spins). This activates catalytic sites to turn ADP + P into ATP.
147
What does chemiosmosis produce?
Chemiosmosis produces about 26 - 28 ATP per glucose.
148
How is a proton gradient formed across the inner mitochondrial membrane?
The exergonic flow of electrons from NADH and FADH2 powers the complexes in the ETC to pump H+ into the intermembrane space.
149
How does ATP synthase obtain energy to convert ADP + P to ATP?
ATP synthase uses energy from the H+ gradient across the membrane (from proton gradient).
150
What are the inputs of pyruvate oxidation?
2 pyruvate
151
What are the outputs of pyruvate oxidation?
2 acetyl CoA, 2 CO2, 2 NADH
152
What are the inputs of oxidative phosphorylation?
10 NADH, 2 FADH2
153
What are the outputs of oxidative phosphorylation?
26 - 28 ATP
154
What is the total amount of ATP that comes from cellular respiration?
30 - 32 ATP
155
When does a pyruvate move into the mitochondria and is oxidized into Acetyl CoA?
when oxygen is present
156
How do organisms produce ATP in the absence of oxygen?
anaerobic respiration & fermentation
157
What is anaerobic respiration?
Anaerobic respiration generates ATP using an ETC in the absence of oxygen.
158
Where does anaerobic respiration take place?
in prokaryotic organisms that live in environments with no oxygen
159
What are the final electron acceptors in anaerobic respiration?
sulfates & nitrates
160
What is fermentation?
Fermentation generates ATP without an ETC. It is an extension of glycolysis. It occurs in the cytosol, requires no oxygen, and recycles NAD+.
161
What are the two types of fermentation?
alcohol fermentation & lactic acid fermentation
162
What is alcohol fermentation?
Alcohol fermentation is when a pyruvate is converted into ethanol.
ex. bacteria, yeast
163
What is lactic acid fermentation?
Lactic acid fermentation is when a pyruvate is reduced directly by NADH to form lactate.
ex. muscle cells
