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MCAT Biochem (Mine) > Chapter 5 > Flashcards

Chapter 5 Flashcards

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MCAT flashcards
1
Q

The bond between two sugar molecules is called what?

A

Glycosidic linkage (they are named based on where they & how they are linked)

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2
Q

The hydrolysis of polysaccharides into monosaccharides is favored _________________

A

Thermodynamically

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3
Q

Enzymes that are used in the hydrolysis of polysaccharides into monosaccharides are named how?

A

Based on the sugar that they hydrolyze (ex. Maltase breaks maltose into two glucose)

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4
Q

Humans & other mammals can’t break down Beta linkages but we can break down lactose due to the enzyme __________ which can digest lactose

A

Lactase

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5
Q

The oxidation of glucose is accompanied by what?

A

NAD+ & FAD where during redox reactions they form NADH & FADH2

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6
Q

__________ is required for activation of adenylate cyclase by cholera toxin & _______ can associate with a protein to become a flavoprotein

A

NAD+, FAD

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7
Q

What is the 4- step process that is used to oxidize glucose?

A
  1. Glycolysis
  2. The pyruvate dehydrogenase complex (PDC)
  3. The Krebs cycle
  4. Electron transport/oxidative phosphorylation
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8
Q

In _____________ (glucose splitting) the glucose is partially oxidized while it is spilt in half into two identical pyruvic acid molecules

A

Glycolysis

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9
Q

Glycolysis occurs in the ____________ & does require oxygen

A

Cytoplasm

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10
Q

In PDC the pyruvate produced in glycolysis is decarboxylated to form an _________ group where that group is then attached to coenzyme A which carries it into the Krebs cycle (small amounts of NADH is produced)

A

Acetyl group

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11
Q

In the Krebs cycle (critic cycle) the acetyl group from PDC is added to oxaloacetate to form _________ acid. The PDC & Krebs cycle occurs in the matrix

A

Citric acid

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12
Q

In electron transport/oxidative phosphorylation, the high energy electron carried by NADH & FADH2 is oxidized by the ____________ in the inner mitochondrial membrane.

A

Electron transport chain

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13
Q

In ___________ a glucose molecule is oxidized and split into two pyruvate molecules, producing a net surplus of 2 ATP(from ADP + P(i) & producing 2 NADH (from NAD+ + H+)

A

glycolysis

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14
Q

What is the formula for glycolysis?

A

Glucose + 2 ADP + 2P(i) + 2NAD+ —> 2 Pyruvate + 2ATP + 2NADH + 2H2O + 2H+

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15
Q

Hexokinase

A

Catalyzes the first step in glycolysis, the phosphorylation of glucose to G6P. G6P feedback-inhibits hexokinase

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16
Q

_________ is produced in only one step: when an aldehyde (-de) is oxidized to a COOH (-ate) (in glycolysis)

A

NADH

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17
Q

_______ is converted to ADP in (in glycolysis) every time a phosphate is added to a substrate & ADP is made into ATP every time a phosphate comes off a substance

A

ATP

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18
Q

Phosphofructokinase (PFK)

A

Catalyzes the 3rd step which is the transfer of a phosphate group from ATP to fructose-6-phosphate to form fructose -1,6-bisphosphate (F1,6bP)

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19
Q

Under aerobic conditions (presence of oxygen) the pyruvate produced in glycolysis enters the PDC and Krebs cycle to be oxidized completely to ______

A

CO2

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20
Q

In ___________ conditions (without oxygen) , electron transport can not function and the limited supply of NAD+ becomes entirely converted to NADH

A

Anaerobic

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21
Q

Fermentation

A

Has evolved to regenerate NAD+ in anaerobic conditions thereby allowing glycolysis to continue in the absence of oxygen

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22
Q

Oxidative decarboxylation

A

Is a reaction in which a molecule is oxidized to release CO2 and produce NADH

23
Q

In _________________ pyruvate is changed from a 3- carbon molecule to a 2-carbon molecule while CO2 is given off and NADH is produced

A

Oxidative decarboxylation

24
Q

The PDC changes pyruvate into an activated _________ unit

A

Acetyl

25
Q

An activated Acetyl means the Acetyl attached to a carrier called _____________

A

Coenzyme A

26
Q

Prosthetic group

A

When a cofactor is very tightly or covalently bound to the enzyme

27
Q

Krebs Cycle

A

Is a group of reactions which take the 2-carbon acetyl unit from acetyl - CoA combine it with oxaloacetate & release two CO2 molecules (NADH & FADH2 are produce in the process)

28
Q

In the first stage of the Kreb cycle what happens?

A

Oxaloacetate (OAA) & acetyl-CoA react together to form citric acid (citrate)

29
Q

On stage 2 of the Krebs cycle _________ is further oxidized to release CO2 & to produce NADH from NAD+ with oxidative decarboxylation

A

Citrate

30
Q

The oxidation of glucose has created what?

A
  1. 2 ATP and 2 NADH per glucose molecule in glycolysis
  2. Pyruvate dehydrogenase: 2 NADH per glucose (one per pyruvate)
  3. Krebs cycle: 6 NADH, 2FADH2, & 2 GTP per glucose
31
Q

What are the two goals of electron transport/oxidative phosphorylation?

A
  1. Reoxidize all the electron carriers reduced in glycolysis, PDC, and the Krebs cycle
  2. Store energy in the form of ATP in the process
32
Q

Oxidative phosphorylation

A

Is the oxidation of the high energy electron carriers NADH &FADH2 coupled to the phosphorylation of ADP to produce ATP

33
Q

Electron - transport chain

A

Is a group of five carbon electron carriers

34
Q

ATP synthase

A

A large protein complex which contains a proton channel that spans the inner membrane

35
Q

The committed step in glycolysis

A

The conversion of F6P to F1, 6bP with the PFK enzyme is the first committed step in glycolysis

36
Q

The two goals of electron transport/oxidative phosphorylation are what?

A
  1. Reoxidize all the electron carriers reduced in glycolysis, PDC, & the krebs cycle
  2. Store energy in the form of ATP in the process
37
Q

Oxidative Phosphorylation

A

Is the oxidation of the high-energy electron carrier NADH & FADH2 coupled to the phosphorylation of ADP to ATP

38
Q

The electron-transport chain

A

Is a group of five electron carriers

39
Q

Beta linkages is when the oxygen on carbon one is ________ & alpha linkage is when its ________

A

Up, down

40
Q

The enzyme used in the hydrolysis of linkages are named by the ___________ they hydrolyze

A

sugar

41
Q

Glycolysis produces what?

A

2 pyruvate molecules , ATP, & NADH (doesn’t require oxygen)

42
Q

________ is however need for the first few steps o f glycolysis

A

ATP

43
Q

Fermentation

A

Regenerates NAD+ in anaerobic conditions so that glycolysis can continue in anaerobic conditions (pyruvate turning into lactate)

44
Q

Excess lactate build goes through the _________ cycle

A

Cori

45
Q

The energy released through oxidation of NADH & FADH2 by the electron transport chain (source of energy to drive the phosphorylation of ADP to ATP) is used to pump out of the _______________ & into the intermembrane space

A

Mitochondrial matrix

46
Q

The electron-transport chain is a group of ______ large electron carriers & each member reduces the next member down the line (& some small molecules)

A

5

47
Q

The 1st large carrier in the electron transport chain is _____________________________

A

NADH dehydrogenase (coenzyme Q reductase)

48
Q

NADH dehydrogenase passes its electron to ___________________________

A

Ubiquinone (Coenzyme Q) (not part of the 5 large member its a small one)

49
Q

Ubiquinone passes its electron to ___________________________ (small molecule) where it passes its electron to ___________________________ (large member) where it then passes its to the last member which is _____________________ (large member)

A

Cytochrome C reductase, Cytochrome C, Cytochrome C oxidase

50
Q

The end product of the electron transport chain is ________

A

H2O (Cytochrome passes its electrons to O2reducing it to H2O)

51
Q

The pentose phosphate pathway (PPP) diverts glucose 6 phosphate from glycolysis to form _________________, ribose 5-phosphate, & glycolytic intermediates

A

NADPH

52
Q

The first enzyme in the PPP is _____________________________ & its the primary point of regulation

A

Glucose 6-phosphate dehydrogenase (G6PDH)

53
Q

In the PPP its product NADPH acts via ______________ feedback to inhibit G6PDH

A

Negative

MCAT Biochem (Mine) (4 decks)

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