Cell respiration Flashcards

1
Q

Define respiration

A

break down molecules (food) for energy (converted to ATP)

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2
Q

Differentiate breathing and respiration

A

Breathing
- inspiration (inhaling) and exhalation
- mainly to exchange gas
Respiration
- “breathing” (external respiration) under this broader term — encompasses also cellular processes where oxygen is used to produce energy and carbon dioxide is the byproduct // (general): break down of organic molecules to gain energy (-> ATP)

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3
Q

Outline the two types of respiration

A

1.) aerobic(oxygen)

2.) anaerobic (w/o oxygen)

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4
Q

Outline the two types of anaerobic respiration

A

1.) Lactic acid fermentation
2.) Ethanol / Alcoholic fermentation

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5
Q

Differentiate lactic acid and ethanol respiration

A

Ethanol respiration
- Done by plants

Lactic acids
- done by animals

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6
Q

If ethanol respiration is present in bread (yeast breaking down food thus producing ethanol), why don’t we get drunk when making bread?

A

High heat in the baking will cook the alcohol and reduce the alcohol contents to be scarcely sensible

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7
Q

Where is most of the respiration happening?

A

In the mitochondria (the powerhouse of the cell)

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8
Q

What happens in the electron transport chain and krebs cycle (DB)?

A

Chemiosmosis

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9
Q

Why does eukaryotic cell has more ATP

A

It has mitochondria — therefore it do the Kreb’s cycle and the electron transport chain

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10
Q

Define glycolysis

A

The breaking down of sugar

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11
Q

Define phosphorylation

A

When a phosphate group adds a phosphate molecule to become unstable (so the added molecule can be rearranged — can break away?)

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12
Q

What is the formula of glucose

A

C6 H12 O6

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13
Q

When a glucose is under glycolysis into 2 molecules what will be their formula?

A

C3 H6 O3

(half of the original formula of glucose)

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14
Q

What kind of respiration is glycolysis?

A

Anaerobic — small net gain of ATP (only 2)

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15
Q

Define cell respiration

A

The controlled release of energy by enzymes: metabolic pathways and cycles

(explanation: via reactions aka metabolic pathways(chains)/cycles the cell is able to produce and control the energy. ig by control, they control some of the enzymes via end-product inhibition for example? not sure)

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16
Q

Where is chemical energy stored?

A

In bonds — which is why respiration is catabolic

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17
Q

How can the energy from glucose be made usable for the body?

A

It must be converted to ATP in order for it to be used by the body

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18
Q

Outline the three organic compounds for energy

A

Carbs, lipids, proteins

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19
Q

Why are lipids so filled with energy

A

Many bonds due to lots of hydrogen bonds (also see the triglycerides)

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20
Q

Define ketones

A

Lipids/fatty acids converted to a form of energy usable by the body

  • Keto diet
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21
Q

Outline the form of ATP

A

light blue pentose - carb (bc of the shape)

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22
Q

Why is the tri-phosphate recognized by energy in the body?

A

The bond between the phosphates contain energy

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23
Q

How do we get ADP (adenosine di-phosphate)

A

When one of the phosphates broke off for energy

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24
Q

How does ADP return to being ATP

A

Stray phosphate bonds to ADP to create ATP (2->3 phosphates)

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25
Q

What is the chemical equation of Cell Respiration 😰

A

(glucose -> C6 H12 O6)
(under the glucose — it says “or other organic molecule”)

in regular words: specifically, glucose plus oxygen forms carbon dioxide plus water.(pay attention to those you know)

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26
Q

What type of respiration is cell respiration?

A

Aerobic
- as seen in the chemical equation, there’s oxygen

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27
Q

How many ATP does anaerobic respiration have per glucose?

A

2 ATP per glucose

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28
Q

In animals. what will anaerobic respiration produce?

A

Glucose - forms -> Lactate + 2 ATP

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29
Q

In plants and yeast, what will anaerobic respiration produce?

A

ethanol + carbon dioxide + 2 ATP

30
Q

Where does anaerobic respiration (glycolysis) happen?

A

Always cytoplasm
- because it has water — breaking down (dissolving?)
- also glucose can’t go into mitochondria as is

31
Q

What is anaerobic resp good for:

A
  • short rapid ATP production (easier to break down glucose rather than lipids.)
  • low oxygen supply in environments (good for anaerobic organisms)
32
Q

When glucose is broken down, what is it called?

A

Pyruvate

33
Q

contrast aerobic and anaerobic resp. on terms of OSYP

A
  • Oxygen: Aerobic: ✅ ; Anaerobic ❌
  • Substrate: Aerobic: Glucose or lipids ; Anaerobic: glucose only
  • Yield of ATP: Aerobic: larger ; Anaerobic respiration: smaller
  • Products: Aerobic: CO2 + water; Anaerobic: (Humans; lactate); (Yeast: CO2 and ethanol)
34
Q

Differntiate aerobic and anaerobic respiration

A
35
Q

Why is the third phosphate that joined to the ADP to create ATP considered “inorganic”? (GUESS)

A

It is because it was originally not part of the ADP but it joined

36
Q

Give the similarities between aerobic and anaerobic respiration

A

On the glycolysis part:
- glycolysis is an anaerobic process
- BUT cell respiration (aerobic) HAS glycolysis

On the production of CO2:
- (Aerobic): e.g. Link reaction produces 2 CO2 (+ 2 NADHs + 2 Acetyl-CoA) from the oxidation of pyruvate
- (Anaerobic): In alcohol fermentation, it produces ethanol + Co2 (+2 ATP)

37
Q

Define catabolic pathway

A

kdown if complex molecules
e/g/: hydrolysis

38
Q

Define redox

A

Oxidation is inseparable with reduction

39
Q

Compare and contrast oxidation and reduction

A
  • Electrons: Oxidation: loss; reduction: gain;
  • Hydrogen: loss; gain (if hydrogen is given away then electron is given away — give & take)
  • Oxygen: Gaining Oxygen; losing oxygen;
  • Product: C-O bonds; C-H bonds (because gaining in hydrogen)*
  • Energy levels: compund w/ lower: cmpnd with higher (due to loss/gain of electrons respectively)

*Why carbon?: present in all organic compounds — thus in living creatures and their life processes like metabolism
Why oxygen? - oxidation: removal of electron -> hydrogen and the addition of oxygen

40
Q

What will be oxidized in cellular respiration (general)0

A

The glucose
(C6H12O6 [glucose] + 6O2 -> 6 Co2 [ oxidation to become carbon dioxide — no hydrogen for glucose] + 6 H2O [ reduction to become water — adding hydrogen/electrons for O] + energy])

41
Q

Define oxidation

A

loss of electrons/hydrogen -> less energy

42
Q

What are the electron carriers with their reduced and oxidized form?

A
  • NAD (oxidized) -> NADH (reduced form)
  • NADP -> NADPH (reduced)
  • FAD -> FADH2 (reduced)
43
Q

Define reduction

A

gain of electrons/hydrogen -> more energy

44
Q

why is the reduced form of FAD is FADH2

A

Because it can hold 2 hydrogen atoms

45
Q

What does the hydrogen represent?

A

Electrons — therefore, it’s an indicator of electron presence

46
Q

What is the other name for pyruvate oxidation?

A

Link reaction

(Because after decarboxylation, the free C atom becomes a CO2 atom. — oxidation)

47
Q

Outline the four main processes of cell respiration

A

Glycolysis, link reaction, citric acid cycle/krebs cycle, electron transport chain

48
Q

At the first step (glycolysis), how many ATP is produced?

A

2 ATP because glycolysis is anaerobic (but not the whole cell resp. bc of ETC)

49
Q

What are the 2 pyruvates converted to in order to get into the mitochondria?

A

2 Acetyl CoA via oxidation (2C -> 3 C)

50
Q

Which stage will yield the most atp

A

ETC with 34 ATP

51
Q

Describe the cell respiration process of glycolysis? (process + end product)

A

2 stages: energy investment and energy harvest.

Energy investment
- Glucose w/ 6 carbons
- 2 ATP borrowed from cytosol and reduced to 2ADP
- 2 phosphates of ADP to go to the two ends of glucose — made unstable to break [phosphorylation, glc-6-PO4]
- [lysis] break down of glucose to 2 pyruvates

Energy Harvest
- Phosphate from cytosol attach to pyruvates — rephosphorylation for later
- Will cause NAD -> NADH + H [oxidation of reduced electron carrier, has an additional hydrogen because each NADH received 2 electrons from G3P]
- [Rephosphorylation] 2 ADP -> ATP [Both process simultaneous, REDOX]

END PRODUCT: 2 Pyruvate + 2 ATP

52
Q

Why does glycolysis only yield 2 ATP at the end?

A

Because paid 2 ATP to start reaction [Energy investment], must pay back by 2 ATP —> 4 ATP (Total “end product”) - 2 ATP(payment) = 2

  • also anaerobic respiration — oxygen not the terminal electron acceptor in glycolysis because the electron carriers like NADH haven’t released their electron (?)
53
Q

Describe link reaction [3]

A

In the matrix
Main objective: convert the 2 pyruvate to 2 acetyl-CoAs by removing one carbon from the two pyruvate
1.) [Decarboxylation] pyruvates oxidized get removed.

2.) The stay/freed carbon will be Oxidized (becomes CO2)
- If there’s oxidization, there’s reduction -> NAD -> NADH
produced 2 NADH (now from glycolysis, total = 4 NADHs because of the 2 pyruvates).

END PRODUCTS: 2 Acetyl-CoA (2C)
2 CO2 and 2 NADH

54
Q

Where does glycolysis happen?

A

Cytosol — water in cytosol break down the glucose

55
Q

Define cristae

A

The inward fold of the mitochondria membrane to maximize surface area

56
Q

Describe krebs cycle

A

objective: have the same start product (bc cycle) and produce as much reduced electron carriers (NADH + FADH2) as possible

CITRIC ACID CYCLE
1.) [Citric acid cycle] The acetic acid-CoA (2 carbons) + oxoloacetate ( a 4 carbon molecule )-> citrate (6 carbons)

DECARBOXYLATION
- ig to oxidize more NAD -> NADH?
2-3.) [Decarboxylation x2] 6 carbons -> 4 Carbons
- [x2 Reduction] NAD -> NADH
- [x2 oxidation] C -> CO2

REGENERATION

4.) No more carbon of original pryuvate, the substance become an oxoloacerate to combine with another acetyl-CoA (which is supplied by the link reaction + glycolysis!)
- Reduced reactions:
- NAD -> NADH
- 2FAD -> 2 FADH2
- 2 ADP -> 2 ATP

57
Q

Describe the electron transport chain

A

In the inner membrane — cristae
- [Oxidative phosphorylation]: oxidation of hydrogen/electron carriers -> synthesis of ATP
-Objective: create ATP

STEP 1: Proton Motive Force
- NADH (and FADH2) supplies 2 electrons (in the ETC) and protons (@ the matrix) to first carrier in the chain.
- The electrons transferred to the electron transport chain
- ^ passing through the chain, ^ loses energy due to proton pumps for pumping energy (pumping the H+ ions) | matrix -> inter membrane space
- creates electrochemical gradient (high - inter-membrane space-> low - matrix) — proton motive force

STEP 2: CHEMIOSMOSIS
- Due to proton motive force, the protons will return to matrix via transmembrane enzyme ATP synthase
- By moving through the ATP synthase, the enzyme will rotate, synthesis of ATP

STEP 3: Reduction of Oxygen
- De-energized protons (travelled using ATP synth) need to be removed (for the ETC to work)
- Oxygen as final electron receptorremoves the de-en. protons by forming water with them via bonding.

58
Q

Why is it called “chemiosmosis?”

A

High to low electron concentration
- like osmosis (passage of water in and out of the cell)
- but replace that with electrons — chemistry-related

59
Q

Define electron transport chain

A

Series of electron carriers in the inner membrane of the mitochondrion including the cristae

60
Q

Why is oxygen the terminal electron acceptor?

A

So remove the de-energized protons which where de-energized from travelling using the ATP synthase.

61
Q

Define the mitochondria part “matrix”

A
62
Q

What is the end product of the electron transport chain?

A

32-34 ATP (total after cell respiration: 36 ATP — 2 from krebs 2 from glycolysis)
H2O
NAD+ (reduced, made positive because electrons fueled the proton pumps0
FAD (ditto)

63
Q

Why will the electron transport chain not work if the de-energized protons are not removed?

A

*Electron flow in the ETC will stop because the reduced NAD cannot go back to NAD -> the supplies of NAD run out (wuh-oh! #shortage alert!) *link reaction and krebs cycle continue no more!**

64
Q

What is the goal of the first step in ETC?

A

Proton motive force - to make the protons matrix -> intermembrane space (for ATP synthesis) -> matrix to remove the de-energized protons

65
Q

What is the goal of the second step in the electron transport chain?

A

To produce ATP by making the protons go through ATP synthase

66
Q

What is the goal of the third step in electron transport chain?

A

To remove the de-energized protons so there’s a steady supply of NADH

67
Q

After cell respiration, what are the products?

A

34-36 ATPs
(2 from Glycolysis, 2 from Krebs, 34 from ETC)

68
Q

Why does phosphorylation make bonds more unstable?

A

It makes bonds more unstable because the addition phosphate: ^ energy = ^ mvmt = ^ more chance for the bond to break = ^ instability

69
Q

What is the purpose of krebs cycle in cell respiration?

A

To produce many electron carriers (3 NADHs, 1 FADH + 2 ATPs — additional)

70
Q

What is the purpose of yeast undergoing respiration?

A

To make the bread rise
- by trapping the end products of anaerobic reaction (water, Co2) inside bread dough as pockets of gas
- The Co2 expands -> bread rise

71
Q

What type of cells does anaerobic reaction take place? And how is this related to their structure?

A

Prokaryotic cells;
- because they have no mitochondria;
- no krebs cycle, and ETC (that’s why they only yield 2 ATP — can only do glycolysis);