Cellular Respiration Flashcards
What is cellular metabolism
the sum of all chemical reactions in a cell
Point of cellular respiration?
Convert energy stored in glucose to ATP
Order of the three phases?
Glycolysis -> Citric acid cycle -> oxidative phosphorylation
Where does Glycolysis occur
In the cytoplasm (anaerobic)
What is the point of Glycolysis
Begin oxidation of Glucose
First reaction of Glycolysis?
Hexokinase (addition of inorganic Pi from ATP makes glucose more reactive)
Third reaction of Glycolysis?
Phosphofructokinase (another ATP required to phosphorylate the sugar)
Meaning of phosphorylate?
Introduce a phosphate group into a molecule
What happens after phosphofructokinase?
Glucose is split into 2x3C (G3P)
Two phases of Glycolysis?
Energy investment (Hexokinase & phosphofructokinase) and energy payoff
First step of energy payoff phase?
NADH is produced from NAD+ (organic C has been partially oxidized)
The first reactions of the energy payoff phase occur __ times each
two
What is substrate level phosphorylation?
When energy for ATP synthesis comes from the dephosphorylating of a substrate (losing P)
How many ATP does Glycolysis provide per Glucose?
Two (2 used, 4 produced)
How many NADH are produced per Glucose in Glycolysis
two
What is the product of Glycolysis?
Pyruvate (3C)
What is the site of cellular respiration?
Mitochondria
How many times does Glycolysis happen per glucose?
twice
Pyruvic acid is _______ into Acetyle CoA by ________ when pyruvate enters the ___________ because otherwise it is ____________.
- oxidized
- Coenzyme A
- mitochondria
- impermeable
How many carbons in acetyl CoA
two
Point of Krebs/Citric acid cycle?
Complete oxidation of glucose (CH -> CO2)
Where does the Krebs cycle occur?
In the matrix
What is FADH2?
Another type of electron carrier (lower energy electrons than NADH)
How many times does the Krebs cycle turn per Glucose?
Twice
How many ATC are produced by the Krebs cycle?
Two
What is the strongest oxidizing agent?
oxygen
What happens at the end of the electron transport chain?
Oxygen is reduced (O2 -> H2O)
What is Chemiosmosis
Synthesis of ATP using an H+ gradient
Where does the energy for chemiosmosis come from (difference btw Photosynthesis and Cell Resp)
In photosynthesis: energy for H+ gradient comes from light (Photophosphorylation)
In Cell resp: energy for H+ gradient comes from redox reactions: glucose (oxidative phosphorylation)
When does fermentation occur
O2 depleted in environmen
What is the point of fermentation?
recycle NAD+ for continued glycolysis in the absence of TEA (oxygen)
How many ATP does fermentation produce per glucose?
two
How does pyruvates role change during fermentation?
Acts as an electron acceptor to free up NAD+
How is pyruvate a “decision point”?
It decides whether or not to enter mitochondria, dependent on presence of O2
What happens when there’s no sugars available?
Secondary source of nutrients is fats (enter Krebs as 2C acetyl CoA)
Tertiary source of nutrients is proteins
What are the two inhibitors of Cellular Respiration?
ATP: when there’s enough ATP, ATP will bind yo phosphofructokinase and cause a change in shape of the enzyme
Citrate: too much acetyl CoA, citrate inhibits PFK
