Section 3: Cellular Respiration Flashcards
This is an overall oxidative, exergonic process
Cellular Respiration
What is the ΔG for cellular respiration
-686 kcal/mole
This is defined as the entry of air into lungs and gas exchange between alveoli and blood
External respiration
This is defined as exchange of gas between the blood and the cells, + the intracellular respiration proccess
Internal Respiration
During respiration, what high energy atoms are removed from organic molecules?
What type of reaction is this?
H atoms
Dehydrogenation
What is the net equation for cellular (aerobic) respiration of glucose
C6H12O6 + 6O2 –> 6CO2 + 6H2O + energy
This type of respiration occurs in the presence of O2
Aerobic Respiration
What are the processes of aerbobic respiration?
What is the final product?
Glycolysis, pyruvate decarboxylation
Water
This is the part of aerobic respiration comprising the decomposition of glucose into pyruvate in cytosol
Glycolysis
How many ATP does glycolysis use?
How much NADH produced?
How much ATP produced?
How much pyruvate produced?
2ATP used
2NADH produced
4 ATP produced
2 pyruvate produced
What is the process that produces ATP during glycolysis?
Substrate level phosphorylation
This part of glycolysis is defined as the direct enzymatic transfer of a phosphate to ADP, no extraneous carriers needed
Substrate level phosphorylation
In substrate level phosphorylation, what enzyme phosphorylates glucose?
This is important because…
Hexokinase
The resulting can’t move out and tricks the gradient?
What molecule adds the 2nd phosphate to glucose?
What is the resulting molecule?
Why is this important?
PFK (phosphofructokinase-1)
fructose 1,6-biphosphate
Because this step is reversible and commits to glycolysis, major regulatory point!
After glycolysis, what occurs?
Where does this occur?
pyruvate decarboxylation
Mitochondrial Matrix
What is consumed and produced in pyruvate decarboxylation?
Pyruvate is consumed
Turns into Acetyl CoA, producing 1 NADH and 1 CO2
The net result is 2 NADH and 2 CO2
What enzyme catalyzes pyruvate decarboxylation?
PDC enzyme (pyruvate dehydrogenase complex))
This is the last step of aerobic respiration for the pyruvate molecules produced during glycolysis
Krebs Cycle aka Citric Acid Cycle aka Tricarboxylic Acid Cycle
In the Krebs cycle, _____ merges with ____ to form _____
The cycle goes with ___ intermediates
Acetyl CoA merges with oxaloacetate to form citrate
7 intermediates
What is produced per turn of the Krebs cycle?
3 NADH, 1 FADH2, 1 ATP (via sub phos), and 2 CO2 are produced per turn
What happens to the 2 CO2 molecules produced during the Krebs cycle in animals?
They are exhaled
What is the net products produced from one molecule of glucose during the Krebs cycle?
How many CO2 produced during both glycolysis and krebs cycle?
Total 6 NADH, 2 FADH2, 2 ATP (technically GTP), 4CO2
This is because there are 2 pyruvate molecules per glucose, multiply the products per turn by 2
6 total!
How is the ATP produced in the Krebs cycle?
Substrate level phosphorylation
Where does the citric acid cycle take place?
In the mitochondrial Matrix
What occurs after the Krebs cycle in aerobic respiration?
Where does it occur
The Electron Transport chain
At the inner membrane/cristae of the mitochondria
What do the cristae (folds) do for the mitochondria and the ETC?
Increase surface area for more ETC action
This is the process of converting ADP to –> ATP from NADH and FADH2 in the ETC via passing of electrons through various carrier proteins.
oxidative phosphorylation
Where does the energy come from in the ETC?
Electrons in the ETC establishing an
H+ gradient that supplies energy to ATP synthase
Which makes more energy, NADH or FADH2?
NADH, more H+ is pumped across per NADH (3:2 yield)
What is the final electron acceptor in the ETC?
Oxygen
What does the final electron acceptor (oxygen) form?
H2O, it combines with native H+
In the ETC, carrier proteins extract energy from NADH and FADH2 while pumping protons into the intermembrane space, what uses this gradient to make atp?
Where does it shuttle the H+ to?
ATP synthase (the gradient is both a pH and electrical)
Back into the inner matrix
This is a soluble carrier dissolved in the membrane that can be fully reduced/oxidized, it passes electrons through the membrane in the ETC
Coenzyme Q/Ubiquinone
This is a protein carrier in the ETC, common in many living organisms, used for genetic relation
They have non protein parts for ____ reactions
Cytochrome C
Redox reactions
This process of the ETC couples exergonic flow of electrons with endergonic pumping of protons across the cistae membrane
Oxidative Phosphorylation
What is the total energy released from glucose in cellular respiration in eukaryotes?
How much in prokaryotes?
~36 ATP
~38 ATP
What accounts for the difference in total energy released from one molecule of glucose in prokaryotes and eukaryotes?
Prokaryotes have no mitochondria so they don’t need to transfer pyruvate to the mitochondrial matrix (requires active transport), they use the cell membrane for respiration
Where does cellular respiration occur in prokaryotes?
The cell membrane
This organelle has an outer membrane, intermembrane space (H+), inner membrane (ox. phosph) mitochondrial matrix (krebs)
Mitochondrial matrix
This is the mechanism of ATP generation in the mitochondria that occurs when energy is stored in the form of a proton concentration gradient across a membrane
Chemiosmosis
Krebs produces ______ and _____ , they are oxidized (lose electrons), H+ transported from matrix to __________
_______, pH and electric charge gradient is created, ATP synthase uses the energy in this gradient to create _____ by letting the protons flow through the channel
NADH, FADH2
Intramembrane space
ATP
increases H+ cxn INCREASES/DECREASES pH
Decreases pH
ATP is a DNA/RNA nucleotide
What type of sugar does it have?
RNA nucleotide
Ribose (like RNA and DNA)
Is ATP stable or unstable? Why?
Unstable because the 3 phosphates are all negatively charged so they repel one another
In ATP, a phosphate group is removed via ____ rxn
This creates a LESS/MORE stable ADP molecule
This releases or absorbs energy?
Hydrolysis
More stable
Releases energy (exergonic)
This molecule provides energy for all cells by transferring one of its phosphates to another molecule
ATP
What are the two processes of anaerobic respiration?
Glycolysis and fermentation
Aerobic respiration regenerates NAD+ via ___, which is required for continuation of glycolysis
O2
Without O2 in glycolysis during anaerobic respiration, there would be no replenishing
______ accumulates, the cell would die with no ATP, so ______ occurs
NADH accumulates
Fermentation
This process occurs in plants, fungi (yeasts) and bacteria (botulinum)
It converts pyruvate to acetaldehyde and CO2,
Acetaldehyde is then converted to ______
And NADH—>
Fermemntation
Ethanol
NAD+
What is the final electron acceptor in anaerobic respiration?
What does this form?
Acetaldehyde
Ethanol (similar to O2 being electron acceptor and forming H2O)
This type of anaerobic respiration occurs in human muscle cells and other microorganisms
Lactic Acid Fermentation
In lactic acid fermentation, pyruvate is converted to
Lactate (and NADH–> NAD+)
In lactic acid fermentation, lactate is transported back to the liver for conversion back to _____ once surplus ATP is available
Glucose
These anaerobes can tolerate oxygen presence but don’t use it
These cannot live in the presence of oxygen
These can grow with or without oxygen because they can metabolise energy aerobically and anaerobically
Aerotolerant anaerobes
Obligate anaerobes
Facultative Anaerobes
When glucose supply is low, body uses other energy sources, in the priority order of:
These substances are first converted to ___ or ___ intermediates, then decraded in ____ or _____
other carbs, fats, and proteins
Glycolysis or CAC
We don’t just break down glucose, we can produce it. This process is called
Where does it occur in the body?
Gluconeogenesis
Liver and Kidney
What organ is responsible for maintaining glucose cxn in the blood?
The liver
This is a glucose polymer, important in the storage of glucose
What amount of glycogen is stored in the liver?
The kidney?
Glycogen
2/3 in liver
1/3 in kidney
____ after large meals stores glucose as glycogen
____ has the opposite effect and turns on glycogen
Insulin
Glucagon
What enzyme does insulin activate/glucagon inhibits it?
PFK enzyme
Disaccharides are converted into ____, most of which can be converted to glucose or glycolytic intermediates
Monosaccharides
All cells in the body are capable of producing and storing glycogen but only ____ cells and especially __ cells have large amounts
Muscle cells and liver cells
Fats store MORE/LESS energy than carbohydrates per carbon
This is because the carbons in fats are in a MORE/LESS reduced state
More energy
more reduced
Triacylglycerides are converted by ______ in the lumen of small intestine to….
Lipases
Monoacylglycerides and fatty acids
Where are the lipases located in the body that convert triacylglycerides to monoacylglycerides and fatty acids
Lumen of the small intestine
The monoacylglycerides broken down by lipases are absorbed in the surface ___ cells
There, they are reformed into _______
These are packed into ____ particles packaged with ____
This creates ___ tissue for storage
Intestinal
Triacylglycerides
Chylomicron particles packaged with cholesterol
Adipose tissue
Adipose tissue is broken down by _______ which creates ____ and _____
Lipases
Glycerol and fatty acids
In the breakdown of adipose tisue, glycerol goes to the ______ for _____ or ______
Fatty acids are converted to _____ which goes to other tissue cells, to the __ organelles. It enters the ___ cycle
liver for glycolysis or gluconeogenesis
Acetyl CoA, goes to mitochondria of cells and enters the CAC cycle
Lipases in adipose tissue are sensitive to _____
hormones (ex: glucagon)
Glycerol in adipose tissue is converted into ___ which enters glycolysis
PGAL (glyceraldehyde 3 phosphate)
When fatty acids are converted to acetyl CoA, every ___ carbon from fatty acid chain makes an Acetyl CoA
Every 2 carbons
Fatty acids in the blood combine with ____ which carriers them
Albumin
Fatty acids are broken down for energy via ________
This takes place in the __________
How many ATP are spent activating the entire fatty acid chain?
Beta oxidation
Mitochondrial Matrix
2 ATP
In fatty acid metabolism, how much NADH and FADH2 does every cut into 2 carbons in SATURATED fatty acids produce?
Therefore, an 18C chain is 9 2C pieces, how many times is it cut?
1 NADH, 1 FADH2 (1 of each)
8 times! tricky business. 9 fragments formed from 8 cuts
How much less FADH2 is produced for each double bond in saturated fatty acids than saturated fatty acids?
1 less FADH2
Note: fatty acid metabolism results in BIG yield of ATP , yields more ATP per carbon than carbohydrates, more energy in fats than
sugars
!
This is the least desirable source of energy, it’s only used when carbs and fat are unavailable
Protein
Most amino acids undergo _____ in the liver
deamination
Amino acids are deminated in the _______ organ
Liver
After AAs undergo deamination, they are converted to _____ or _____ or other CAC intermediates, enter cellular respiration at these various points (varies by AA)
Pyruvate or Acetyl CoA
Oxidative deamination removes _____ molecules directly from AAs.
Ammonia
Ammonia, released after deamination of AAs, is _______ to vertebrates
Fish excrete it, insects and birds convert in to uric acid, mammals convert to urea for excretion
Toxic
