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GNUR 150 Human anatomy > Human physiology chapter 3, cell metabolism > Flashcards

Human physiology chapter 3, cell metabolism Flashcards

1
Q

define cell metabolism

A
  • the sum of all chemical reactions occurring in a cell
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2
Q

define energy metabolism

A

reactions involved in energy storage and use

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3
Q

define catabolic

A
  • breakdown of larger molecules into smaller molecules
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4
Q

define anabolic reactions

A

synthesis of larger molecules from smaller reactants

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5
Q

Define hydrolysis and its formal

A
  • reactant side: breaks bonds sing H20
    formula: A-B + H20 = A-OH + H-B
    (Eg. sucrose + h20 = glucose + fructose)
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6
Q

define condensation and its formula

A
  • product side: make new bonds - releasing H20
    A-OH + H-B = A-B + H20
    (eg: glucose + fructose = sucrose + H20)
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7
Q

define phosphorylation and its formula.

A
  • adding phosphate group (+Pi)
  • reactant side: adding inorganic phosphorous)
    A + Pi = A-P
    (eg: ADP + Pi = ATP + H20)
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8
Q

Define dephosphorylation and it’s formula

A
  • removing a phosphate group (-Pi)
  • product side: releasing inorganic phosphorous
    A-P = A + Pi
    (eg: ATP = H20 = ADP + Pi (also a hydrolysis reaction)
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9
Q

what is a oxidation reduction reaction?

A
  • oxidation = loss of electrons
    • removal of electrons:
      A* + B AB*
      where * is an electron
      A is oxidized (loses electron)
      B is reduced (gains electron)
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10
Q

What is ATP synthesis

A
  • ADP + Pi + energy → ATP (+ H2O)
  • A condensation reaction
  • A phosphorylation reaction
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11
Q

what is a EXERGONIC REACTION

A
  • energy is released
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12
Q
A
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13
Q

what is glucose oxidation?

A
  • the central reaction of energy metabolism
  • ΔE = –686 kcal/mole
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14
Q

how much energy is released durring glucose oxidation

A

= 686 kcal

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15
Q

what are the 4 stages of glucose oxidation?

A
  • glycolysis
  • Krebs cycle
  • oxidative phosphorylation
  • electraon transport chain
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16
Q

what is glycolysis?

A
  • breakdown of glucose to 2 pyruvate molecules
  • sequence of 10 enzyme - catalyzed reactions that take place in the cytosol
  • naet gain of 2 ATP moleucles
17
Q

How does glycolysis get linked to the Kerbs cycle?

A
  • pyruvate get converted to acetyl CoA
  • unidirectional
18
Q

what is the Krebs cycle?

A
  • the sequence of reactions by which most living cells generate energy during the process of aerobic respiration. It takes place in the mitochondria, consuming oxygen, producing carbon dioxide and water as waste products, and converting ADP to energy-rich ATP.
19
Q

what is the first step of the Krebs cycle?

A
  1. Acetyl-CoA Formation: The cycle begins when a molecule called acetyl-CoA combines with a four-carbon molecule called oxaloacetate to form a six-carbon molecule called citrate. This step is catalyzed by the enzyme citrate synthase.
20
Q

What is the second step of the krebs cycle?

A

Isomerization: Citrate undergoes a series of rearrangements and isomerizations to form its isomer, isocitrate. This step is catalyzed by the enzyme aconitase.

21
Q

what is the third step of the krebs cycle?

A

Alpha-Ketoglutarate Formation: Isocitrate is then oxidized to form alpha-ketoglutarate, releasing carbon dioxide and reducing the coenzyme NAD+ to NADH. This step is catalyzed by the enzyme isocitrate dehydrogenase.

22
Q

what is the fourth step of the Krebs cycle?

A

Succinyl-CoA Formation: Alpha-ketoglutarate is oxidized to form succinyl-CoA, releasing another molecule of carbon dioxide and reducing NAD+ to NADH. This step is catalyzed by the enzyme alpha-ketoglutarate dehydrogenase complex.

23
Q

what is the fifth step of the Krebs cycle?

A

Succinate Formation: Succinyl-CoA is then converted into succinate while transferring a phosphate group to GDP, forming GTP (which can later be converted into ATP). This step is catalyzed by the enzyme succinyl-CoA synthetase

24
Q

what is the sixth step of the Krebs cycle?

A

Fumarate Formation: Succinate is oxidized to form fumarate, reducing FAD to FADH2. This step is catalyzed by the enzyme succinate dehydrogenase, which is unique because it is bound to the inner mitochondrial membrane and participates in both the Krebs cycle and the electron transport chain.

25
Q

what is the seventh step of the krebs cycle?

A
  • Malate Formation: Fumarate is hydrated to form malate. This step is catalyzed by the enzyme fumarase.
26
Q

what is the eighth step of the Krebs cycle?

A

Oxaloacetate Regeneration: Malate is oxidized to form oxaloacetate, reducing NAD+ to NADH. This completes the cycle, as oxaloacetate can then combine with another molecule of acetyl-CoA to begin the process again.

27
Q

what is oxidative phosphorylation?

A
  • Glycolysis + Krebs cycle = net gain of 4 ATP molecules
  • Bulk of ATP is formed in the electron transport chain
  • Movement of electrons down the electron transport
    chain is used to synthesize ATP
  • Requires oxygen
28
Q

what is the electron transport chain?

A
  • Electron transport system: chain of molecules in the
    inner mitochondrial membrane
  • Molecules undergo oxidation-reduction reactions, going
    from high to low energy
  • Energy released is used to synthesize ATP by oxidative
    phosphorylation
  • ATP synthase
  • Last electron acceptor = O2
    Donation of electrons to chain
  • NADH + H+ → NAD+ + 2 H+ + 2 e–
  • FADH2 → FAD + 2 H+ + 2 e–
  • Final accepting of electrons
  • 2 e– + 2 H+ + 1⁄2 O2 → H2O
    STEP 3: Electron Transport Chain
    Reducing (removes H+) coenzymes: NAD and FAD
29
Q

what does glucose catabolism in the absence of o2 look like?

A
  • electron transport chain backs up
  • Krebs cycle stops
  • glycolysis can continue only if NADH is oxidized
  • lactate is synthesized
30
Q

what is the effect of the conversion of pyruvate to lactate?

A
  • allows muscles to operate in low o2 conditions
  • ## atp production is inefficient
31
Q

what is gluconeogenesis?

A
  • synthesis of new glucose molecules
  • occurs mainly in liver
  • Not simply the reverse of glycolysis—other enzymes are involved
32
Q

What does the suffix ase stand for?

A
  • something relating to phosphate
  • Hexokinase (adds phosphate groups to glucose)
  • Glucose-6-phosphatase (removes phosphate groups
33
Q

How is energy stored?

A
  • Most energy is stored as triglycerides
  • Triglycerides = 3 fatty acids + glycerol
  • Lipids have greater energy per weight than
    carbohydrates or proteins
  • Most triglycerides are stored in adipocytes
34
Q

what is lipolysis?

A
  • breaking down lipids
  • Triglycerides + lipases → glycerol + 3 fatty acids
35
Q
A

GNUR 150 Human anatomy (14 decks)

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