Cellular respiration Flashcards
(139 cards)
1
Q
Luft syndrome
A
Over active mitochondria. Lots of oxygen being used, little ATP being produced.
2
Q
Diseases the mitochondria effects
A
ALS, Parkinson’s, Alzheimer’s, Huntington’s disease
3
Q
Mitochondria
A
Key reactions of cellular respiration occur here. Energy from food molecules is taken and used
4
Q
Cellular respiration
A
Collection of metabolic reactions that break down food molecules and use the free energy to make ATP
5
Q
Biosynthetic reactions
A
AKA anabolic reactions.
6
Q
Production of carbohydrates
A
In photosynthesis light energy extracts electrons from water. The electrons connect CO2 and H+ to make glucose
7
Q
Carbohydrates make
A
Proteins and fats with their energy
8
Q
Biproducts of photosynthesis
A
Oxygen. Which is needed for cellular respiration. A continual cycle
9
Q
What are carbohydrates good fuel
A
An abundance of C—H bonded molecules
10
Q
C—H bonds
A
High energy because their electrons are held equally between the two atomic nuclei loosely. Easily removable to do work
11
Q
C—O bonds
A
More electronegative, so lower potential energy because electrons are being held tighter to oxygen
12
Q
Why fats are more Kcal
A
Only made of C—H bonds so more energy is produced
13
Q
Oxidized
A
Losing an electron and becoming more positive
14
Q
Reduced
A
Gaining an electron and becoming more negative
15
Q
Redox reactions
A
The complimentary processes of oxidation and reduction happening
16
Q
Redox reaction basis
A
Xe- + Y —- X + Ye-
17
Q
Oxidation name
A
Many fuels oxidized involve oxygen as the molecule that gains electrons and gets reduced
18
Q
Oxygen in reactions
A
Car engines, oil fires and cellular respiration
19
Q
Redox problems
A
Not all reactions involve oxygen
Electrons can be transferred completely of incompletely
20
Q
Incomplete electron transfer
A
A shift in how much an electron is shared between 2 atoms
21
Q
Redox of glucose
A
Through combustion energy is released as electrons to oxygen, reducing water. Carbon is oxidized to CO2
22
Q
Glucose activation energy
A
High. A flame or enzyme-catalyst can be used to each a small activation energy. The thermodynamics are the same
23
Q
Difference in glucose activation energy
A
A flame creates a large amount of sudden heat, controlled combustion creates small amounts of usable energy
24
Q
Dehydrogenases
A
Enzymes that facilitate electrons from food to an energy carrying molecule (shuttle)
25
Nicotinamide adenine dinucleus
NAD+ oxidized, NADH reduced
26
NADH
A coenzyme and the most common energy carrier. Removes 2 H+ and returns 2 electrons and one proton. Highly efficient
27
Main job of cellular respiration
Turn potential energy in food into ATP, glucose goes through all the steps and therefore is our focus
28
Phases of CR
Glycolysis, pyruvate oxidation and citric acid cycle, oxidative phosphorylate
29
Glycolysis
Glucose and enzyme--- 2 pyruvate +some ATP + some NADH
30
Pyruvate oxidation and citric acid cycle
Pyruvate oxidation---acetyl coenzyme A which is oxidized into CO2. Some ATP and NADH is formed
31
Oxidative phosphorylate
NADH is oxidized from electrons traveling down the electron transport chain until oxygen turn's into H2O. Free energy creates a proton gradient used to make ATP
32
Archaea and bacteria
Glycolysis and citric acid cycle in the cytosol, oxidative phosphorylation occurs in the internal membrane
33
Eucharyotes
Step 2 and 3 take place in the mitochondria
34
Glycolysis in detail
10 enzyme catalyzed reactions leading to the oxidation of 6 carbon glucose. Produces 2 pyruvate molecules, ATP and NADH.
35
Experiment discovering glycolysis
100 years ago they proved you can do reactions in an isolated, cell free environment. The foundation of biochem
36
Glycolysis is ancient because
1. It is universal between bacteria, archaea, and eukaryotes
2. It does not need oxygen (life existed before oxygen did)
3. Occurs in the cytosol. Not requiring complex, evolved organelles
37
3 concepts of glycolysis
Energy investment followed by pay off
No carbon is lost
ATP is generated by substrate level phosphorylation
38
Energy investment followed by payoff
Has two phases. Energy requiring and energy releasing
39
Energy requiring phase
5 steps. 2 ATP's used by glucose and fructose. 6-phosphated becomes phosphorlated
40
Energy returning phase
4 ATP and 2 NADH are produced
41
No carbon is lost
Glucose (6 carbons) becomes 2 pyruvate (3 carbons). Oxidation has occurred as the potential energy of pyruvate is less than the glucose
42
ATP is generated by substrate level phosphorylation
A phosphate group is transferred from a high energy substrate to ADP making ATP used in the citric acid cycle
43
Pyruvate oxidation and the citric acid cycle
Extraction of remaining free energy and trapping it in ATP and electron carriers
44
Pyruvate movement
Cytosol to outer MM through simple diffusion to the inner MM passes using a pyruvate specific membrane carrier into the mitochondrial matrix
45
Pyruvate oxidation
Multistep process where pyruvate becomes acetyl-CoA
46
Step 1-Decarboxlation reaction
Carboxyl (COO-) is removed from pyruvate and becomes co2
47
Step 2-Acitate production
The oxidation of the 2-carbon molecules produces acetate
48
Step 3-Dehydrogenation reaction
2 electrons and a proton are transferred to NAD+ making NADH
49
Step 4-CoA
Acetyl group reacts with CoA forming high energy acetyl CoA
50
Citric acid cycle
C-H bonds exist in acetyl CoA, here they are broken and the energy is used. 8 enzyme catalyzed reactions.
51
Reactions 1-7
Soluble enzymes in the mitochondrial matrix
52
Reaction 8
Bound to the matrix side of the inner membrane. Is insoluable
53
Citric acid cycle overall
The acetyl group is oxidized, ATP, NADH, and FAD are made
54
FAD
Nucleotide base molecule flavin adenine dinucleotide. Reduced to FADH2
55
1 turn of the citric acid cycle
3 NADH, 1 FADH2, 1 ATP, 2 CO2 is made from 1 acetyl unit. All of the C is now CO2
56
CoA molecule carrier
Released to participate in pyruvate oxidation after carrying the CoA
57
Citric acid cycle equation
1 acetyl CoA + 3 NAD+ + 1 FAD + 1 ATP + 1 Pi + 2H2O----2CO2 + 3 NADH + 1 FADH + 1 ATP + 3 H+ + 1 CoA. Double the coefficients when thinking of glycolysis because 2 pyruvates were formed
58
Oxidative phosphorylation
Except ATP all energy is now in NADH or FADH2
59
ETC and chemiosmosis
Take remaining potential energy and make ATP
60
Repository ETC
A system on the inner mitochondrial membrane. Electrons from NADH and FADH2 turn into oxygen molecules
61
4 proteins of the ETC
Complex 1-NADH dehydratase
Complex 2-Succinate dehydratase
Complex 3- Cytochrome complex
Complex 4- Cytochrome oxidase
62
Complexes 1, 3, 4
Are made from multiple proteins
63
Ubiquinol
Hydrophobic, found in the core of the inner MM. Acts as a shuttle between complex 1 and 2 and 2 and 3
64
Cytochrome
Shuttles electrons from complex 3 to 4. On the intermembrane side of the inner MM
65
Prosthetic groups
Non protein molecules that transport electrons in the ETC. Redox active cofactors that alternate between red/ox. Accept electrons from upstream, donate downstream
66
Heme
A cytochrome that is the oxygen carrying part of hemoglobin. Contains redox active iron. Fe2+---Fe3+
67
Protein subunits
Bind to prosthetic groups 1-3 precisely.
68
Electron transport path
FMN (reduced) + electrons from NADH--- Fe/S--- ubiquinone---...--- oxygen--- water
69
FNM
Flavin mononucleate. Prosthetic of complex 1. There is an excess of H+ in cells for their use
70
Why does the ETC occur
Prosthetics organize high to low free energy. NADH easily oxidized starts to oxygen which is easily reduced ends. Occurs because of theromdynamics
71
In the ETC
No ATP is made, just water
72
Energy released during ETC
Does work by transporting protons across the inner MM from inside the matrix to out. The intermembrane space increases in H+ and decreases in pH
73
Proton translocation
Uses energy from electron release. Ubiquinone brings electrons from the matrix to the third complex, drops 2 protons in the intermembrane space so it can be neutral
74
Proton gradient
Creates potential energy that can do work. 2 factors
75
Factor 1
Chemical gradient exists because proton concentration is skewed
76
Factor 2
Proton charge creates an electrical gradient, creating proton motive force.
77
Chemiosmosis
Harnessing proton motive force to do work. Makes ATP and moves the flagella
78
Oxidative phosphorylation
ATP synthesis linked to oxidation of energy high molecules in the ETC. Relays on ATP synthase
79
ATP synthase
Large multiprotein complex spanning the inner mitochondrial membrane. Consists of the basal unit, head, and stalk. Forms a channel for H+ to freely travel
80
Basal unit
Embedded in the inner MM
81
Head
Extends into the matrix. A proton bonding here makes it spin and an ATP is formed from ADP
82
Stalk
Connects the head and basal unit
83
Active transport pump
Uses the free energy from hydrolysis of ATP
84
Proton gradient and evolution
Evolved early as plant, animal, bacteria, and archaea all use it
85
Coupled processes
ATP from the ATP synthase to the ETC via proton gradient. These reactions can be uncoupled
86
The ETC doesn't
Make ATP
87
Ionophores (uncouplers)
Form channels for ions (protons) to flow freely through. Proton gradient cannot happen with these because the protons can flow freely back.
88
Ionophores toxicity
Cause weight loss and were promoted as a weight loss drug in the 1930's
89
Uncoupled reactions
Energy from ETC is lost as heat rather than establishing proton motive force
90
Uncoupling proteins
Localized to the inner MM and help regulate body temperature
91
Oxidative phosphorylation products
For every NADH (2e-) 10 protons go into the intermembrane space.
3-4 flow back though the ATP synthase
92
How many molecules per NADH
3
93
How many ATP's per FADH2
2
94
Glycolysis products
2 ATP and 2 NADh
95
Citric acid cycle products
2 ATP, 6 NADH, 2 FADH2. Now there is a total of 2 FADH2 and 10 NADH's for the ETC
96
How many total ATP are made
38/mole of glucose, ideally
97
Why is 38 rarely acheived
38 is for bacteria, reaction coupling, and proton motive force
98
38 is for bacteria not eukaryotes
Eukaryotes need ATP for pyruvate transport from the cytosol to the M matrix
99
Reaction coupling
ETC and oxidative phosphorylation ae rarely fully coupled. The inner MM is naturally leaky to protons
100
Proton motive force
Used for other processes such as moving pyruvate
101
Kcal
ADP to ATP produces 7.3 kcal/mol
1 mol produces 263 kcal of energy
Full glucose oxidation provides 686 kcal/mol
102
Cellular respiration effecency
38% of energy in glucose becomes ATP. Lots goes to entropy
103
Sucrose CR
And other disaccharides are broken into monosaccharaides and enter like glucose
104
Starch CR
It is hydrolyzed into glucose by digestive enzymes
105
Glycogen
In broken down into glucose-6-phosphate
106
Fats CR
Triglycerides are hydrolyzed into glycerol and fatty acids.
Glycerol becomes glceraldehyde-3-phosphate and enters glycolysis
Fatty acids- Become acetyl-CoA and enter the citric acid phase
107
Proteins
An amino acid group is removed from the amino acid. The rest enters as pyruvate. Acetyl is carried by CoA or intermediates the citric acid cycle
108
Repiritory intermediates
Supply carbon backbone for hormones, growth factors, prosthetic groups, and cofactors
109
CR rate
Regulated by how much energy the cell needs. Supply and demand through feedback inhibition
110
Glycolysis control
An allosteric enzyme phosphofructokinase who's workings are effected by ATP and ADp
111
ATP phosphofructokinase
Inhibits PFK from working when it is in excess, therefore fructose- 1,6 biphosphate concentration decreases
112
ADP phosphofructokinase
An allosteric activator for PFK
113
Citrate
First product of the citric acid cycle. High build up inhibits PFK because the demand for ATP is low
114
Fermentation
Oxygen-less cellular respiration without the citric acid cycle or ETC
115
Anarobic respiration
Oxygen-less cellular respiration with the citric acid cycle and ETC
116
Fermentation details
Occurs when eukaryote cells don't have oxygen for CR. Pyruvate remains in the cytosol and in reduced, consuming NADH---NAD+
117
Types of fermentation
Lactate and alcohol
118
Lactate fermentation
Bacteria, some plants, and animals. Pyruvate is turned into a 3-carbon molecule lactate. When oxygen becomes present the reverse reaction happens forming NADH and pyruvate
119
Alcohol fermentation
Microorganisms. Pyruvate is reduced to ethyl (co2 is released) and NADH--NAD+
120
Saccharomyces Cervidae
Yeast in bread. The rising occurs from CO2, baking kills the ethyl alcohol
121
Natural fermentation
Over ripe fruit
122
In fermentation
Not enough ATP is made to support the brain, so it is only used in times of emergency
123
Bacteria and Archaea ETC
Most have them in their internal membrane systems. Some are similar to eukaryotes and use oxygen others don't (anaerobic)
124
Anaerobic respiration
Not using oxygen as the final electron acceptor but rather SO42-, NO3-, or FE3+
125
Why did aerobic respiration evolve
Because oxygen loves electrons, leading to the highest extraction of potential energy
126
3 lifestyles of organisms
Strict aerobes, facultative anaerobes, strict anaerobes
127
Strict aerobes
Some archaea, bacteria, and eukaryotes. Must use oxygen to survive
128
Facultative anaerobes and examples
Can switch between fermentation and aerobic respiration. E. coli, yogurt bacteria, brewing and baking yeast
129
Strict anaerobes
Few fungi and bacteria. Only survive in oxygen free environments. Use fermentation or anaerobic respiration. Bacteria that cause botulism or tendonitis
130
Paradox of aerobic life
Oxygen is essential for life, but can be toxic to some organisms
131
Why can be oxygen dangerous
Oxygen +4e- ---H2O. If 3 or less electrons are present they become powerful oxidizing agent like superoxide's or H2O2, stealing electrons from proteins, lipids and DNA
132
Reactive oxygen species (ROS)
If it is high, it can be lethal. A part of aerobic life that is unavoidable (3 of less electrons on oxygen)
133
In response to ROS
An antioxidant defense system is creates. Enzymes and non enzymes that intercept and inactivate them
134
2 enzymes in ROS
Superoxide dismutase-Turns the super oxide into H2O2.
| Catalase-Reduces H2O2 to water
135
Vitamins C and E
Play the same role as enzymes is ROS
136
Excess ROS is linked to
Parkinson's disease, and Alzheimer's disease
137
Why do anaeroibs die in oxygen
They lack one or both the enzymes or oxygen inhibits key metabolic reactions
138
Cytochrome oxidase
The last enzyme of the ETC produces almost no reactive oxygen. It is a complex with 4 redox centers
139
Redox centers
All hold and release 1 electron at the same time making reactive oxygen into unreactive water
