Chapter 9: Cellular Respiration Flashcards
What are the two types of muscle fiber?
Slow Twitch & Fast Twitch
Slow Twitch
Sustain repeated contractions
For endurance
Not meant for power
Great for long distance running
Fast Twitch
Contract quicker than slow fiber
Fatigue easily
Meant for power
Great for short distance running
What are the key pathways of cellular respiration?
Glycolysis, Kerb/Citric Acid Cycle, oxidative phosphorylation,
Fermentation
A catabolic process that partial degrades sugar (carbs) w/out oxygen
Aerobic Respiration
Oxygen is consumed as along w/ the organic fuel
Oxygen is needed to gain energy from food molecules
Anaerobic Respiration
Oxygen is not used as a reactant in the reaction
Inorganic
Cellular respiration
A chemical process in which oxygen is used to make energy from glucose
C6H12O6 +6O2–> 6CO2 + 6H2O+ Energy (ATP + Heat)
Redox Reaction
A transfer of one or more electron from one reactant to another
Oxidation
The loss of electrons from one substance
Reduction
The addition of electrons to another substance
Reducing Agent
The electron donor
Oxidizing Agent
The electron acceptor
In cellular respiration, what is getting oxidized?
Glucose
In cellular respiration what is being reduced?
Oxygen
Where does the hydrogens from glucose go to?
Oxygen
Why does cellular respiration doesn’t oxidize all of glucose at once?
Because the cell wouldn’t be able to harness all the energy that is released all at once efficiently.
After electrons are stripped from glucose, where are the electrons 1st transferred to?
NAD+
What is NAD+
A coenzyme that is an electron carrier acts as an oxidizing agent during respiration
How does NAD+ trap electrons from glucose
Dehydrogenase enzyme remove a pair of enzymes from substrate thereby oxidizing it. The enzyme delivers the 2 electrons and 1 proton to the coenzyme NAD+
What does NAD+ become?
NADH
Why is NADH neutral?
1 proton 2 electron
What do NADH represent
Stored energy
How can NADH be tapped to make ATP?
When the electrons complete their fall down the energy gradient from the NADH to oxygen
How do electrons extracted from glucose and then stored as potential energy in NADH finally reach oxygen?
There is a release of energy (exergonic reaction)as the electrons from the hydrogens fall towards the electronegative oxygen “bottom” lower energy end of electron chain
Electron Transport Chain
Breaks the fall of the electron to the oxygen into several energy releasing steps occurs in the mitochondria membrane
Electrons drop in free energy as they go down the chain and are passed to O2
Electrons are passed through a number of proteins including cytochromes(each w/ iron atom) to O2
Generates no ATP
Purpose is to maintain manageable amounts of energy release
Crista
A fold in the inner mitochondria membrane
Where do the NADH & FADH2 shuttle the electrons to
The “top” higher energy end of the electron transport chain
What carry’s the electrons to the oxygen?
Series of electron carriers that are more electronegative downhill than the uphill carrier so that it’s capable of oxidizing the other carrier, series of redox reactions
What are the parts of the oxidative phosphorylation?
Electron transport and Chemoisis
Glycolysis
Occurs in the cytsol/cytoplasm , begins the degradation process by breaking glucose into two compounds called pyruvate
“Sugar splitting”
Glucose is split into two 3-carbon sugars, oxidized and then rearranged to make pyruvate.
In cytoplasm, no oxygen needed
Citric Acid Cycle /Kerb Cycle
In mitochondria, completes the breakdown of the glucose by oxidizing a derivative of pyruvate to carbon dioxide.
Needs oxygen
What happens to on the energy released at each stage of the electron transport?
The energy gets stored in a form that the mitochondrion can use to make ATP
The small amounts of energy is utilized to build a concentration gradient of H+ ions across the membrane
What % of ATP does the oxidative phosphorylation account for in respiration?
Almost 90%
Substrate Level Phosphorylation
The smaller amount of ATP formed directly in a few reactions of glycolysis and kerb cycle
When an enzyme transfers a phosphate group from substrate molecule to ADP
Directly for Direct Use
1 second supply
What are the 2 phases of glycolysis
Energy investment and energy payoff
Energy investment phase
Cell spends ATP
Energy Payoff
Energy spend during investment is repaid w/ interest
What is the net energy yielded from glycolysis per glucose molecule?
2 ATP + 2 NADH
Step 1 of Glycolysis
Hexokinase enzyme phosphorylated glucose, this transfers a phosphate group from ATP to sugar
ATP—> ADP
Step 2 of Glycolysis
Glucose-6 phosphate is converted to its isomer fructose-6 phosphate
Step 3 of Glycolysis
Phosphofructokinase transfers a phosphate group from ATP to the sugar (2 total ATP been used). W/ phosphate groups on opposite ends, sugar is now ready to split
Step 4 of Glycolysis
Adolase, enzyme cleaves the sugar molecule into 2 dif. 3 carbon sugars, dihydroxyacetone phosphate and glyceraldehyde-3 phosphate. Sugars are isomers to each other
Step 5 of Glycolysis
Isomerase catalyzes the reversible conversion b/tw 2 3 carbon sugars. This reaction never reach equilibrium b/c next enzyme only uses glyceraldehyde-3 phosphate
Step 6 of Glycolysis
Step 7 of Glycolysis
Step 8 of Glycolysis
Step 9 of Glycolysis
Step 10 of Glycolysis
Myoglobin
Red protein found in mitochondria
Carrier of Oxygen
Muscle cells appear dark when there is a lot of it in the muscle
Muscle cells w/ myoglobin appear lighter in color
Dark Meat
High in Myoglobin
Carry large amounts of oxygen
Less susceptible to fatigue
Found in wing, leg, thigh muscles of turkeys
White Meat
Low amount of myoglobin
Carry small amounts of oxygen
Highly susceptible to fatigue and cramping
Found in thigh muscle of turkey
How efficient is aerobic respiration?
40%
How efficient is anaerobic respiration?
2%
How many ATP does it take to power 1 muscle cell/sec
It takes 10,000 ATP per seconds
Oxidation Phosphoryation
The cells store potential energy in a form of a gradient and releases it all at once to create ATP
In mitochondria, generates ATP, needs oxygen
Chemiosmosis
The cell stores potential energy in concentration gradient across the a membrane & uses it to make energy in ATP.
Performed in mitochondria, across the cristae membrane.
The energy in the concentration gradient is used to power the ATP synthesis
Why isn’t there a large explosion in cellular respiration?
The hydrogen that reacts with oxygen is derived from organic molecules not H2, ETC uses many small redox reactions reducing the amount of energy
Phosphofructokinase
Allosteric enzyme can be inhibited and activated
How many of the original 6 carbons from glucose are left
6
What occurs at the beginning of Kerb’s Cycle
The 3 carbon pyruvate is converted into 2 carbon acetyl coenzyme A
NADH is made for each pyruvate invested (2 total)
CO2 is made from each pyruvate invested (2 total)
How many of the original 6 carbons from glucose is left? After Kerb cycle
4, 2 carbons are lost as CO2 in intermediate step
What do you need in total of the Kerb’s Cycle?
2 Acetyl CoA, 6NAD+, 2FAD, 2ADP +P
What to gain in total after the Kreb Cycle?
4CO2, 6NADH, 2FADH2, 2ATP
How many of the original 6 carbons from the glucose are left after the kreb cycle?
0
After Glycolysis and Kerb Cycle, How many ATPs are made?
4 net
Where is most of the energy from glucose is now?
In NADH, FADH2
How much ATP does NADH make ?
About 3
How much ATP does FADH make
2 ATP
After glycolysis, kerb cycle, chemoisis, how many ATP will there be?
38 under ideal conditions, 36 at the lowest
What are the types of fermentations?
Yeast: produce ethyl alcohol & CO2.
Can be added to grapes to make wine.
Animal and Bacteria: produce lactic acid and CO2
Can be added to milk to make cheese
