Cellular Respiration: How our body uses what we eat Flashcards

(48 cards)

1
Q

_______________is stored in food due to the arrangement of the electrons in the bonds?

A

potential energy

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2
Q

Bonds must be ___________to release energy?

A

Broken

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3
Q

What are the two pathways of cellulular respiration?

A
  • aerobic
  • anaerobic
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4
Q

energy harvested is used to produce__________

A

ATP

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5
Q

the equation for aerobic respiration is?

A

: C6H12O6 + 6O2 ——————> 6 CO2 + 6 H2O + ATP

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6
Q

What role do redox reactions play in respiration?

A

transfer of electrons releases energy stored in organic molecules.

: C6H12O6 + 6O2 ——————> 6 CO2 + 6 H2O + Energy (ATP and heat)

is exergonic

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7
Q

energy is harvested in a _____manner?

A

stepwise

-electrons stripped from glucose at key steps in the process

e- don’t travel alone-travel with a proton=hydrogen atom

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8
Q

if glucose were oxidized all at once?

A

too much energy would be lost

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9
Q
A
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10
Q

Hydrogen atoms are not tranferred directly to oxygen. They are passed to ______________

A

electron carrier–NAD+ (NADH reduced)

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11
Q

What are the stages of cellular respiration?

A
  1. Glycolysis
  2. Pyruvate Oxidation and the Citric Acid Cycle
  3. Oxidative Phosphorylation
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12
Q

What is the equation for glycolysis?

A

glucose+2ATP+2NAD+—->2 pyruvate +4 ATP (2 NET) + 2NADH

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13
Q
  1. Pyruvate Oxidation and the Citric Acid Cycle
A

Pyruvate + Coenzyme A + NAD+ Acetyl CoA + CO2 + NADH Acetyl CoA + H2O + 3 NAD+ + FAD 2 CO2 + H2O +3 NADH + FADH2 + GTP (ATP)

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14
Q

Oxidative Phosphorylation

A

NADH + FADH2 + ½ O2 + ADP + Pi ATP + H2O + NAD+ + FAD

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15
Q

where does glycolysis take place?

A

cytosol

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16
Q

what happens during glycolysis?

A

glucose split into two molecules of pyruvate

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17
Q

How much ATP does glycolysis require? how much does it yield?

A

2, yields 4

net yield: 4 ATP

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18
Q

An enzyme transfers a phosphate group from a substrate molecule to ADP instead of using ______

A

pi

in image–products used in the next step

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19
Q

in Pyruvate Oxidation:

  1. Pyruvate enters the mitochondria through?
A

active transport

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20
Q

What reactions take place?

A

reactions take place – COO‐ is removed and given off as co2

– Remaining 2‐carbon molecule is oxidized :NADH

formed – Coenzyme A is added to form acetyl CoA (high potential energy)

21
Q

Citric Acid Cycle (Krebs/TCA Cycle) consists of 8 steps–each step is catalyzed by a specific enzyme..

What kind of reactions?

where does it occur?

A

redox

mitochondrial matrix

22
Q

one krebs cycle produces?

how many products are produced per glucose molecule?

A

2 CO2

1 GTP (ATP)

3 NADH

1 FADH2

2X that produced by one cycle

23
Q

in the citric(krebs/TCA cycle) what is recycled?

A

coA and oxaloacetate

24
Q

• Per glucose molecule…

A

– glycolysis + 2 ATP

– krebs+ 2 ATP TOTAL

= Net + 4 ATP

25
Most of the energy extracted from glucose is tied up in ________ and _________ So how do we use these molecules to make ATP?
NaOH FADH2
26
what does Oxidative Phosphorylation do?
Generates ATP by adding Pi to ADP
27
what are the steps of oxidative phosphorylation?
electron transport chain chemiosmosis **This is where the majority of ATP is produced**
28
What is the electron transport chain?
collection of molecules embedded in the mitochondrial inner membrane
29
\_\_\_\_\_\_\_are dropped off by NADH and FADH2?
Electrons electron carriers alternate between redced and oxidized states as they accept and donate electrons. -the final electron acceptor is oxygen which also picks up 2 ions to form H2O (still no atp production)
30
Chemiosmosis •
Exergonic flow of electrons is used to pump H+ across the membrane (into the intermembrane space) – Generates a gradient = proton motive force
31
chemiosis
the energy‐coupling mechanism that uses energy stored in a H+ gradient to drive cellular work NOTE: NADH and FADH2 enter the ETC at different complexes = less energy for ATP synthesis when e‐ come from FADH2
32
Using the Proton‐Motive Force to Generate ATP ATP synthase
• \_\_\_\_\_\_\_\_\_\_\_= uses energy of the H+ gradient to power ATP synthesis – Located in the mitochondrial inner membrane • H+ ions flow through ATP synthase down their concentration gradient – Bind to active sites and cause __________________ = rotor spins – Activates catalytic sites that generate ATP **bulk of ATP produced**
33
H+ ions flow through ATP synthase down their concentration gradient – Bind to active sites and cause __________________ = rotor spins – Activates catalytic sites that generate ATP
confrontational change
34
why does the amount of atp that we get vary?
1. # of NaDH molecules to ATP molecules aren't in a 1:1 ratio of NADH molecules to ATP molecules produced not 1 to 1 • 1 NADH = 10H+ pumped across membrane and ~4H+ =1 ATP • 1 NADH = 2.5 ATP and 1 FADH2 = 1.5 ATP – ATP yield varies depending on shuttle used to transport e‐ into mitochondria – Use of proton motive force to drive other work (i.e the uptake of pyruvate) – Proton leakage (wear and tear on membranes, not working as efficiently, not using proton t run ATP synthase
35
\_\_\_\_ of the PE of glucose is transferred to ATP? what happens to the rest?
34% released as heat
36
37
what does anaerobic respiration use?
still uses electron transport chain but O2 isn't the final electron acceptor - other electronegative substances can also work - some marine bacteria use so42-, produce h2s instead of water other substances include: NO3, CO2, S, Fe, uranium (used to clean radioactivity)
38
what is fermentation?
process to generate energy without using oxygen on the electron transport chain Basically an extension of glycolysis (glucose splits to pyruvate)– Glycolysis + a process to regenerate NAD+ • Different types of fermentation – Differ in the end products formed – Two common types: alcohol and lactic acid fermentation
39
Alcohol Fermentation
allows glycolysis by making sure that NAD+ is available • Pyruvate is reduced to ethanol--\> biproduct purpose: regenerate NAD+--wouldn't be able to pick up more pyruvate looses co2 as bread rises, pocket where co2 was before evaporation * Used by some bacteria and yeast * Used to make beer, wine, liquor and bread!
40
What is the purpose of lactic acid fermentation?
NAD+ - pyruvate is reduced directly to by NADH to form lactate - used to make yogurt, cheese muscle cells uses this process when supply of oxygen is unable to keep up with the energy demand- -working out--not enough oxygen--\> switch to LAF (no oxygen to anaerobic. cooling down is important for flushing out extra lactic acid (muscle soreness)
41
what is the purpose of fermentation?
to regenerate NAD+ so that glycolysis continues, need to have NAD+ to pick up electrons for glycolysis form NaDH--\>NAD+
42
What happens when you're deprived of oxygen?
oxygen--final electron acceptor if its blocked Electron chain shuts down--no protons are in the inner membrane, no gradient, can't make atp--cells will die without receiving the energy that they need
43
why can't cells switch to fermentation when suffocating?
fermentation can't make enough ATP (2 net atp, not enough to keep cell alive) cellular 30 for 2 glucose
44
How do we use other molecules for energy?
-glucose isn't the only molecule that can be broken down-other carbs, fats, proteins can be used.
45
A gram of fat produces 2x the ATP generated from 1g of carbohydrate. WHY? Why does this make it hard to lose weight?
fat 2x atp- a lot more hydrogens can be stripped off 2x as hard to burn it off, 2x as much energy
46
Biosynthesis •
Cells need building blocks to make their own molecules – Food provides the carbon skeletons necessary in addition to energy • Amino acids can be incorporated into cell’s own proteins • Many intermediates from glycolysis and the Krebs cycle can be used as precursors for molecules the cell requires • Requires energy (anabolic)
47
How is Cellular Respiration Regulated?
* Follows principles of supply and demand * Prevents cell from wasting energy making something it already has * Main mechanism of control is feedback **inhibition**
48