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MSK Week 1 > Glycolysis > Flashcards

Glycolysis Flashcards

1
Q

General Results for Glycolysis

A

6 carbon glucose molecule to two 3 carbon molecules (each called pyruvate) Needs 2 ATPS to make 4 ATPs = 2 net ATPs produced Anaerobic, does not need oxygen

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2
Q

First irreversible rxn

A

take glucose, and using hexokinase we take a phosphate from that ATP to make it ADP and use that phosphate to make Glucose 6 Phosphate

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3
Q

Second irreversible rxn

A

It happens after we use Phosphoglucose isomerase to turn our Glucose-6-phosphate to Fructose 6-Phosphate. We take another phosphate from another ATP (this is our second ATP for investment) and do the above step again to make the complex have 2 phosphates. This time it is done via PK-1 or Phosphofructokinase-1.

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4
Q

Final Irreversible rxn

A

Phosphoglycerate mutase followed by Enolase turn our 3-PGs to phosphoenolpyruvates (PP), which are acted on by Pyruvate Kinase to turn our PPs into Pyruvates (the last irreversible rxn of glycolysis), in the process generating 2 ATPs from 2 ADPs (remember everything is X2)

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5
Q

Draw out the iireversible tautomerization reaction that turns our enol pyruvate to a pyruvate in keto form

A
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6
Q

Draw glycerol

A
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7
Q

Draw glyceraldehyde

A
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8
Q

Draw glyceric acid

A
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9
Q

Draw glycerate

A
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10
Q

Draw Acetone

A
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11
Q

Draw Hydroxy-Acetone

A
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12
Q

Draw di-hydroxy acetone

A
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13
Q

Why are certain glycolysis steps irreversible?

A

Making these irreversible is great for fast energy production, but these steps must be bypassed during gluconeogenesis in the liver.

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14
Q

How does glucose enter the cell?

A

Passive transport via GLUT4

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15
Q

What are the 3 irreversible steps in glycolysis

A

Step 1: Glucose to G6P

Step 3: F6P to F16BP

Step 10: PEP to pyruvate

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16
Q

What steps produce ATP

A

Step 7: 13BPG to 3-phosphoglycerate

Step 10: PEP to pyruvate

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17
Q

What does glucokinase have a high Km

A

A high Km (aka low affinity) means that glucose uptake in the liver is restricted to when blood glucose is very high

Unlike hexokinase, glucokinase is not inhibited by its products and continues to function until blood glucose levels drop to normal level

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18
Q

What is the major product of digestion of carbohydrates?

A

Glucose, but some galactose and fructose are also produced

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19
Q

Pentose Phosphate Pathway

A

G6P used to make NADPH (which is used in the biosynthesis of fatty acids) and ribose-5-phosphate (nucleotide production)

20
Q

What is a carbohydrate?

A

Compounds that contain at least three carbons, a number of hydroxyl groups, and usually an aldehyde or ketone group

21
Q

Where can glucose and fructiose be phosphorylated?

A

On carbons 1 and 6

22
Q

Common dissarcharides

A

Maltose, Lactose, and Sucrose

I DIe watching soccer (MLS)

23
Q

What happens to RBCs when they are exposed to high levels of blood glucose?

A

The glycosylated fraction of hemoglobin (normally 4-6%) increases

Measuring this is helpful when determining glycemic control for individuals with diabetes

24
Q

Proteoglycans

A

Found in the EM or ground substance of connective tissue, synovial fluid, virteous humor, secretions of mucus-producing cells, and in cartilage

25
Q

Glycoproteins

A

Serve as enzymes, hormones, antibodies, and structural proteins

Found in the extracellular fluid and in lysosomes

Involved in cell-cell interactions

26
Q

What are the major dietary carbohydrates?

A

Strach, sucrose, and lactose

27
Q

What is glycogen?

A

The major storage form of carbohydrate in animals

28
Q

What does glycogen degradation produce?

A

glucose-1-phosphate, but free glucose is also formed

29
Q

What controls glycogen breakdown in the liver?

A

Glucagon and epinephrine via cAMP

30
Q

What controls muscle glycogen breakdown?

A

Epinephrine via cAMP

31
Q

Glycogen synthesis

A

Glucose enters the cell and is phosphorylated to G6P

Phosphoglucomutase converts G6P to G1P

G1P reacts with UTP, forming UDP-glucose (catalyzed by UDP-glucose pyrophosphorylase)

32
Q

What is the key regulatory enzyme for glycogen synthesis

A

Glycogen synthase (transfers glucose residues from UDP-glucose to the nonreducing ends of a glycogen primer)

33
Q

What is the key regulatory enzyme for glycogen degradation?

A

Glycogen phosphorylase: removes glucose residues, one at a time, from the nonreducing ends of glycogen molecules

Produces G1P

34
Q

Regulation of glycogen degradation

A

Glucagon (liver cells) and epinephrine (live and muscle) activate adenylate cyclase, which converts ATP to cAMP

cAMP activates protein kinase A

protein kinase A phosphorylates glycogen synthase (less active) and phorphorylase kinase

Phosphorylase kinase phsophorylates phosphorylase b, converting it to its active from, phosphorylase a (good luck)

phosphorylase a cleaves glusose residues, producing G1P

35
Q

What activates phosphorylase b?

A

AMP (occurs during muscle contraction)

36
Q

What activates phosphorylase kinase?

A

Calcium (released from SR)

37
Q

Insulinomas

A

Leads to hypoglycemia

Stimulaion of glucose transport into the muscle and fat cells

38
Q

Glucagonomas

A

Leads to hyperglycemia, as the liver is instructed to release glucose via glycogenolysis and gluconeogenesis in the presence of glucagon

39
Q

GLUT1 deficiency

A

The GLUT1 transporter translocates glucose across the blood-brain barrier

When one allele is defective, the rate of glucose entry into the nervous system is insufficent for the cells’ needs, leading to seizures, developmental delays, and microcephaly

40
Q

Deficiency of pyruvate kinase

A

Leads to decreased production of ATP from glycolysis

RBCs have insufficient ATP for their membrane pumps, and a hemolytic anemia results (oxygen delivery to tissues is not necessarily affected)

41
Q

Why does pyruvate kinase deficiency not necessarily lead to decreased oxygen delivery?

A

As phosphoenolpyruvate accumulates, it is converted to 2PG, which leads to increased levels of 2,3BPG in the RBCs

Elevated levels of 2,3BPG promote oxygen release from hemoglobin

42
Q

Major sites of regulation in skeletal muscle

A

Hexokinase and PFK1

43
Q

Major sites of regulation in the liver

A

Glucokinase, PFK1, and pyruvate kinase

44
Q

What determines if pyruvate is converted to lactate or acetyl-CoA

A

The activity of pyruvate dehydrogenase

45
Q
A

MSK Week 1 (14 decks)

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