8.1 Flashcards Preview

PR - Big book > 8.1 > Flashcards

Flashcards in 8.1 Deck (49)
Loading flashcards...
1
Q

ribose

A

is glucose without the third finger

“the RIB is missing the third bone”

2
Q

hydrolysis of polysaccharides is/is not thermodynamically favorable?

A

YES, MONOSACCHARIDES are lower energy than polysaccharides. we GET ENERGY from breaking down polysaccharides

3
Q

Glycolysis

A
produces ATP and NADH (2 each, net)
occurs CYTOPLASM (how does NADH get into the mitochondria - glycerol phosphate shuttle / malate-acetate shuttle)
does NOT require oxygen
4
Q

Pyruvate dehydrogenase (PDH)

A

pyruvate is decarboxylated to form an acetyl group

which is attached to coenzyme A with a Sulfur

2 NADH is produced per glucose

5
Q

Mg2+

A

required for ALL reactions involving ATP

stabilizes the negatives

6
Q

NADH is produced during glycolysis when

A

an glyceraldehyde (GAD3P) is oxidized to COOH (-ate) in the 5th step of glycolysis

mediated by GAP-DH (glyceraldehyde dehydrogenase)

7
Q

glycolysis ATP is made

A

when a phosphate comes OFF a substrate

is consumed when a phosphate is ADDED to a substrate

8
Q

PFK

A

Phosphofructokinase (3rd step, phosphorylates F-6-P)

irreversible, a “COMMITTED STEP”

Note: it is allosterically down-regulated by ATP, even though a reactant is ATP

9
Q

coenzyme A (CoA)

A

attached to acetyl unit, used to pass acetyl around (useful in fatty acid and cholesterol synthesis)

10
Q

pyruvate is oxidized/reduced to form acetyl-CoA

A

decarboxylated = oxidized

PDH

11
Q

glycerol phosphate shuttle

A

transports NADH from cytoplasm to the mitochondria, delivers directly to Ubiquinone (like FADH2) which generates 1.5 ATP per NADH

12
Q

Flavoprotein

A

FAD - useful in redox

13
Q

PGK and PK

A

In the second half of glycolysis, these KINASES take phosphates FROM the substrate and create 1 molecule of ATP

PK - 10
PGK - 7 (reversible)

pk = pyruvate kinase (think point to the right)
pgk = phosphoglycerate kinase
14
Q

HK, PFK

A

“Hong Kong is first”

they are kinases that phosphorylate in steps 1 and 3 of glycolysis - they PLACE phosphate on the substrate = LOSS OF ATP

15
Q

Gluconeogenesis

A

We’re out of GLUCOSE AND GLYCOGEN

occurs in LIVER (and kidneys)

NONCARB precursors -> glucose

precursors include LACTATE, PYRUVATE, Krebs cycle intermediates (less Krebs = more energy), carbon skeleton of amino acids

REQUIRES NADH and ATP

16
Q

Regulatory control of glycolysis

A

Steps 1, 3, and 10 are most IRREVERSIBLE

HK, PFK, PK

17
Q

glycerol enters (in gluconeogensis)

A

at DHAP

18
Q

phosphorylated glucose

A

CANNOT CROSS THE CELL MEMBRANE

dephosphorylation must occur before glucose can leave the liver

19
Q

ATP and GTP are

A

HYDROLYZED = release energy

20
Q

pyruvate carboxylase

A

CARBOXYLASE = ADD CARBOXYL GROUP (COOH)

1st step of gluconeogenesis

21
Q

PHOSPHATASE

A

two useful at the END of gluconeogenesis

  1. Fructose-1,6-bisphosphatase
  2. Gluce-6-phosphatase
    - TASE = REMOVE PHOSPHATES

“TASER removes criminals”

22
Q

Steps of glycolysis that gain and lose ATP

A
Step 1: LOSE ATP
Step 3: LOSE ATP
Step 6: GAIN 2 NADH
Step 7: GAIN 2 ATP
Step 10: GAIN 2 ATP

gluconeogenesis (steps in reverse order)

Step 1: LOSE 2 ATP
Step 2: LOSE 2 GDP
Step 5 (same as step 7): LOSE 2 ATP
Step 6: LOSE 2 NADH

GNG: needs 4 ATP, 2 GTP, and 2 NADH

23
Q

what intermediates can take part in GNG?

A

most intermediate of cellular respiration

EXCEPT ACETYL-COA

Free fatty acids CANNOT be converted to glucose

Glycerol backbone CAN

24
Q

GNG is highly

A

ENDERGONIC

25
Q

starvation mode induces…

A

glycogenolysis, gluconeogenesis, lipolysis, and ketogenesis

REDUCE insulin, INCREASE glucagon and epi and norepi

ELEVATED cellular AMP which ACTIVATE PFK and inhibit F-1,6-BPase

26
Q

glucagon

A

associated with Gluconeogenesis

27
Q

insulin stimulates

A

F-2,6-BP, which stimulates PFK, which stimulates glycolysis, inhibits F1,6-bPase and therefore reduces gluconeogenesis

28
Q

what regulates?

A
  1. Enzymes that are irreversible
  2. Intermediates inhibit (citrate decrease PFK)
  3. Energy supplies

Respiration is stimulated by high ADP:ATP NAD+/NADH

inhibited by the opposite

29
Q

memorize the glycolysis/gluconeogenesis table (p. 157)

A

Glycolysis is downregulated by ATP (“Think, the purpose of glycolysis is to MAKE ATP”)

30
Q

Glycogenesis and glycogenolysis occur in

A

LIVER and SKELETAL MUSCLES

skeletal muscle LACKS glucose-6-phosphatase; the glucose stays phosphorylated and cannot leave the muscle cell

31
Q

insulin stimulates

A

GLYCOLYSIS AND GLYCOGENESIS (“we have lots of sugar, let’s create more glycogen”)

decreases GNG (“we have enough glucose”

32
Q

glucagon stimulates

A

GLYCOGENOLYSIS, when blood sugar is low, release glucose from the liver into the blood

“Break down glycogen, we need more glucose”

and GNG.

33
Q

NADPH

A

reducing agent in ANABOLIC processes = Fatty Acid synthesis

NEUTRALIZES ROS!!

34
Q

PPP primary enzyme

A

the first step is Glucose-6-phosphate dehydrogenase (G6PDH) = PRIMARY POINT OF REGULATION = inhibited by NADPH

G-6-P -> 6-phosphogluconate

35
Q

pyruvate decarboxylase

A

First step in alcohol fermentation; REMOVE a CO2 from pyruvate

create Acetylaldehyde (2 carbon)

36
Q

ETC is… versus substrate level phosphorylation

A

OXIDATIVE PHOSPHORYLATION!! NADH, FADH2

Substrate-level phosphorylation occurs with production of ATP or GTP from ADP and GDP (2 per krebs cycle)

37
Q

fatty acid catabolism

A

an ALTERNATIVE to glycolysis/cellular respiration

38
Q

fermentation products

A

Lactate, ethanol

DRAW the steps (ethanol is two carbon, meaning pyruvate had to be decarboxylated via PDC)

Lactate keeps the carboxylic acid, reduces the carbonyl group

39
Q

Hexose monophosphate shunt

A

PPP

produces NADPH and Ribose-5-phosphate, and intermediates of glycolysis

40
Q

Ribose-5-phosphate

A

5 carbon: produces nucleotides

41
Q

glycogen metabolism (glycogenolysis): phosphoglucomutase (reversible), glycogen phosphorylase (adds P to glucose)

A

glycogen phosphoryLASE = 1 glucose is REMOVED from glycogen and phosphorylated to form Glucose-1-P

Glucose-1-P and Glucose-6-P is reversible, enzyme is phosphoglucomutase

G-6-phosphaTASE = REMOVES phosphate (phosphotase = REMOVE!)

42
Q

Phosphorylase versus kinase

A

Phosphorylase and kinase are very similar

Phosphorylase takes from INORGANIC phosphate sources

43
Q

glutamATE versus glutamic acid

A

ATE is the ANIONIC FORM

“acid has the H”

44
Q

3PG

A

phosphoglyceric acid (anionic form) - this is a carboxylic acid

PGK = kinase that takes phosphate from ATP and adds it to 3PG

45
Q

ENOlase

A

cleaves C-O bonds

Step 9 of glycolysis

removes H2O

46
Q

PEP carboxykinase (PEPCK)

A

the 2nd step of GNG

2 GTP -> GDP
two CO2 leave

form PEP

47
Q

hormonal control of Glycolysis and GNG

A

F-2,6-bP

up-regulates PFK, inhibits fructose-1,6-bisphosphatase

reciprocal control

insulin + (lots of glucose, low ADP), glycolysis

glucagon - (little glucose, high ATP), GNG

48
Q

ATP downregulates

A

Glycolysis

49
Q

CAC is regulated by…

A

ATP and NADH

step 3) isocitrate dehydrogenase (D->S)

step 4) α-ketoglutarate dehydrogenase