Unit 3: Cellular Energetics Flashcards

1
Q

metabolism

A

sum of all of an organism’s chemical reactions

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2
Q

catabolic reactions

A

chemical reactions that release energy by breaking down molecules

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3
Q

anabolic reactions

A

chemical reactions that consume energy by building larger molecules

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4
Q

spontaneous process

A

process that occurs on its own in an organism

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5
Q

free energy

A

energy of a system that is easily availiable work; denoted by G

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6
Q

endergonic reactions

A

nonspontaneous reactions that are not energetically favorable; consume energy; positive change in G

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7
Q

exergonic reactions

A

spontaneous reactions that are favorable; release energy; negative change in G

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8
Q

What are the three kinds of work that a cell does?

A

Chemical work
Transport work
Mechanical work

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9
Q

ATP

A

adenosine triphosphate; “energy currency” in the cell. When one of the phosphates is broken off, releases energy that can be used for work

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10
Q

What is ATP made of?

A

Adenine nucleotide
Ribose sugar
3 Phosphate groups

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11
Q

energy coupling

A

using energy from a exergonic reaction to power an energy-requiring endergonic reaction

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12
Q

phosphorylated intermediate

A

a molecule that has a phosphate attached to it from ATP and is unstable

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13
Q

catalyst

A

speeds up a chemical reaction without being consumed by the reaction

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14
Q

activation energy

A

the energy needed to weaken molecules enough so that their bonds can break

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15
Q

enzyme

A

protein that speeds up a chemical reaction by lowering the activation energy

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16
Q

substrate

A

reactants that enzyme will act on

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17
Q

active site

A

parts where the substrate binds

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18
Q

products

A

final substances formed from the substrates

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19
Q

induced fit

A

the idea that the enzyme active site will change its shape so that it fits the substrate

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20
Q

What mechanisms does an enzyme use to lower activation energy?

A

Stressing and bending the chemical bonds
Provides an optimal environment for chemical reactions to take place
The active site directly binds to substrates and binds the substrates together

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21
Q

What factors affect enzyme function?

A

The initial concentration of substrate
pH
Temperature

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22
Q

cofactor

A

nonorganic substance that help enzymes function

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23
Q

coenzymes

A

organic substances that help enzymes function

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24
Q

competitive inhibitors

A

mimic substrate and fight for active site to inhibit enzyme

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25
noncompetitive inhibitors
bind to another place on enzyme other than the active site to inhibit enzyme
26
allosteric regulation
enzyme's function is inhibited via the binding of a regulatory molecule to a separate site other than the active site
27
allosteric activator
increases activity of enzyme
28
allosteric inhibitor
decrease the activity of an enzyme
29
cooperativity
when one substrate binds to one subunit of an enzyme, all other substrates have an affinity for that substrate
30
feedback inhibition
when the product of a metabolic pathway inhibits the enzyme of the metabolic pathway
31
cellular respiration
the process by which eukaryotic organisms turn glucose into ATP energy
32
What is the equation for cellular respiration?
C6H12O6 + 6O2 ----> 6CO2 + 6H2O
33
redox reactions
chemical reactions where electrons are transferred between two substances
34
reduction
gaining of electrons
35
oxidation
loss of electrons
36
reducing agent
substance that gives off electrons
37
oxidizing agent
a substance that gains electrons
38
electron carrier
substance that can hold electrons
39
NAD+ and NADH
electron carrier in cellular respiration that holds one electron and one H+ proton
40
What is the final electron acceptor in cellular respiration?
Oxygen
41
oxidative phosphorylation
set of ATP producing processes involving the electron transport chain and chemiosmosis
42
substrate-level phosphorylation
ADP is phosphorylated into ATP
43
glycolysis
breakdown of glucose into two pyruvates in the cytosol
44
What are the two phases of glycolysis?
energy investment and energy payoff
45
What are the products of glycolysis?
2 pyruvate, 2 net ATP, and 2 NADH
46
How is pyruvate converted into acetyl COA?
CO2 is removed | pyruvate is oxidized by NAD+
47
pyruvate dehydrogenase complex
converts pyruvate into acetyl COA
48
citric acid cycle (Krebs cycle)
oxidizes acetyl COA into 3 NADH, 1 FADH2, ATP, and 2 CO2; runs twice per glucose, once per pyruvate
49
chemiosmosis
movement of H+ ions across the inner membrane of the mitochondria through ATP synthase to form ATP
50
electron transport chain
series of enzymes that break the transfer of electrons from NADH to Oxygen into several small steps, so that energy is not wasted in one explosive step and send H+ ions outside the matrix
51
What happens during oxidative phosphorylation?
NADH and FADH2 release their electrons and protons into the electrons transport chain to power the transfer of H+ protons into the intermembrane space of the mitochondria. The H+ protons flow back through ATP synthase producing ATP from ADP and organic Phosphate. The electrons then go to oxygen to form water using H+ ions as well. 30-32 ATP is produced per glucose
52
fermentation
anaerobic metabolic reactions that give energy
53
What is the electron acceptor in fermentation?
Pyruvate
54
Alcohol fermentation
glucose splits into pyruvate, and CO2 is removed from pyruvate to form acetaldehyde, which is reduced by NADH to form ethanol, recycling NAD+ to be used again. Produces 2 ATP every cycle
55
lactic acid fermentation
glucose split into 2 pyruvates, pyruvate reduced by NADH to form lactate, recycling NAD+ to be used again
56
photosynthesis
formation of glucose using sunlight, water, and carbon dioxide
57
What is the equation for photosynthesis?
6CO2 + 6H2O + sunlight energy ----> C6H12O6 + 6O2
58
What happens in the light reactions in photosynthesis?
1. light as photons strike chlorophyll in photosystem 2 in the light-harvesting complex, which is passed around from chlorophyll to chlorophyll until reaches the central chlorophyll a and excites electrons there. 2. The excited electrons from chlorophyll a are transferred to the primary electron acceptor, which becomes reduced. 3. H2O is split into 2H+, 1/2 O2, and electrons, (O2 is released as a by-product). The H and O are released into the thylakoid space. 4. The electrons travel from PS2 to PS1 via the electron transport chain, releasing the electrons' energy to form an H+ gradient. 5. The H+ gradient makes ATP in chemiosmosis 6. photons strike chlorophyll in PS1 exciting electrons until they reach the central chlorophyll of PS1. 7. electrons transfer to NADP+ reductase reduce NADP+ into NADPH for the Calvin cycle.
59
What happens in the calvin cycle?
ATP and NADPH energy are used in the process of fixing CO2 to a 5-carbon chain in a cycle to form glucose
60
absorption spectrum
measures how well different pigments absorb different wavelengths of light
61
action spectrum
measures how well photosynthesis works on different wavelengths of light
62
photosystem
protein complex with a reaction center complex surrounded by light-harvesting complexes; where conversion of solar energy to chemical energy occurs
63
light harvesting complex
harvests light using its numerous chlorophyll molecules. Photon light energy is passed from chlorophyll to chlorophyll until it reaches the central chlorophyll a
64
reaction center complex
holds chlorophyll-a molecules as well as a primary electron acceptor
65
primary electron acceptor
becomes reduced when receives electrons, completing the conversion of light energy to chemical energy
66
What happens in the Calvin cycle?
1. 3 CO2 are fixed to 3 RuBP (5-C sugar) by an enzyme called rubisco to make 3 6-carbon chains 2. the 3 6-Carbon chains are broken into 6 3 carbon chains, which are then "zapped" by NADPH with electrons as well as being phosphorylated by ATP to form 6 G3P. One of these G3P goes to become glucose by attaching to another one from a second cycle. 3. The other 5 G3P are recycled into 3 RuBP to complete the cycle
67
C3 plant
direct organic product of carbon fixation is 3 carbon compound of G3P
68
photorespiration
rubisco fixes O2 to RuBP rather than CO2 to RuBP, which can kill plants
69
C4 plant
CO2 is first fixed to a 4-C sugar, which is broken down to 2 CO2 to then be used again in Calvin cycle
70
CAM plant
at night, collect CO2, at day, release it and use it with ATP and NADPH in the Calvin cycle normally