CELLULAR RESPIRATION Flashcards Preview

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Flashcards in CELLULAR RESPIRATION Deck (24)
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1
Q

What s cellular respiration?

A

A group of catabolic reactions that are jointly called “cellular respiration”

CONSISTS OF:

  • glycolysis
  • Citric Acid Cycle
  • Electron Transport Chain
2
Q

Why is glucose important in these reactions?

A
  • Is the primary source of fuel
3
Q

how does glucose enter the cell?

A
  • using a glucose transport protein - insulin aids in sneaking glucose thru the membrane
  • The cells then begin glucose catabolism and use the energy to create ATP
4
Q

What are anaerobic and aerobic reactions?

A
  • anaerobic: doesn’t require oxygen
  • Aerobic: does require oxygen
    ( most ATP is produced by aerobic reactions)
5
Q

Where does glycolysis take place?

A
  • In the cytosol and doesn’t require oxygen
6
Q

How much ATP does glycolysis produce?

A
  • TWO ATP
7
Q

How much ATP does the citric acid cycle produce?

A
  • TWO ATP
8
Q

How much ATP does the electron transport chain produce?

A
  • generates about 28 ATP.
9
Q

How much ATP is produced per glucose molecule?

A
  • typically 32
10
Q

What are the general characteristics of glycolysis?

A
  • Both aerobic and anaerobic pathways begin with glycolysis
  • Consists of ten enzyme-catalyzed reactions that break down a 6-carbon glucose molecule into two 3-carbon pyruvic acid molecules
11
Q

What are the 3 steps in glycolysis?

A
  1. Priming by phosphorylation
  2. Cleavage
  3. Formation of NADH + ATP
12
Q

What is the first step of glycolysis in detail?

A
  1. Two phosphate groups are added to a glucose molecule, one at each end, in a step called PHOSPHORYLATION.”
  2. This step requires energy from TWO ATPS, which are used to PRIME the glucose to ready it for the upcoming reactions
13
Q

What is the second step of glycolysis in detail?

A
  1. The 6-carbon glucose molecule is cleaved into two 3-carbon molecules
14
Q

What is the third step of glycolysis in detail?

A
  1. The hydrogen carrier NADH is formed, ATP is synthesized, and two 3-carbon pyruvic acid molecules result
15
Q

What happens to the “high energy” electrons released during glycolysis?

A
  • Electrons that are released during glycolysis are hydrogen atoms + contain much of the energy from the chemical bonds in the original glucose molecule
16
Q

What is NAD+ and how is it related to the hydrogen atoms?

A
  • To use hydrogen atoms as cellular energy, they are passed in pairs to bind with NAD+ molecules
    2 protons + 2 electrons bind to the molecules of the hydrogen carrier NAD+
17
Q

How does NAD+ change after the hydrogen bonds bind to it?

A

NAD+ + 2H –> NADH + H+

18
Q

What does NADH do with the hydrogen atoms?

A
  • NADH delivers hydrogen atoms with high energy electrons to the electron transport chain in the mitochondria to be synthesized as ATP
  • NADH is an electron carrier
19
Q

How many ATP are synthesized during glycolysis?

A
  • 4 ATP are synthesized directly, subtracting the 2 ATP molecules in the priming process
  • This yields a net gain of 2 ATP per molecule of glucose
20
Q

What are the products of glycolysis?

A
  • when one glucose molecule is broken down there are 2 ATP and 2 pyruvic acid molecules
21
Q

What is oxygen’s role at the end of the electron transport chain?

A
  • For cellular respiration to continue, NADH + H+ must be able to deliver hydrogen atoms to the electron transport chain to replenish the supply of NAD+
  • This can only happen in the presence of oxygen
  • It is the final electron accept at the end of the ETC
    that enables the chain to continue processing hydrogen atoms and recycling NAD+
22
Q

What happens without oxygen in the Electron Transport Chain?

A
  • The NADH+ has nowhere to unload its hydrogen atoms
  • As an alternative NADH + H+ can give its hydrogen atoms back to the pyruvic acid in a reaction that forms lactic acid
  • this inhibits glycolysis and ATP production declines
23
Q

What is the citric acid cycle?

A
  • Takes place in the fluid of the mitochondrial matrix
  • The citric acid cycle begins when a 2-carbon acetyl CoA molecule combines with a 4-carbon oxaloacetic acid molecule to form a 6-carbon citric acid and CoA
  • The citric aid is changed thru a series of reactions back into oxaloacetic acid
  • The cycle repeats as long as the mitochondrion receives oxygen and pyruvic acid
24
Q

What are the 3 important consequences of the citric acid cycle?

A
  1. One ATP is produced directly for each citric acid molecule that goes thru the cycle
  2. For each citric acid molecule, 8 hydrogen atoms with high-energy electrons are transferred to the hydrogen carriers NAD+, and the related molecule FAD

NAD+ + 2H —> NADH + H+
FAD + 2H –> FADH2

  1. As the 6-carbon citric acid reacts to form the 4-carbon oxaloacetic acid, two carbon dioxide molecules are produced.