Gluconeogenesis

Question 1

Glucuneogensis

Answer 1

new production of glucose. makes sugar

Question 2

Liver glycogen depleted in:

Answer 2

overnight fast

Question 3

Glucose is the major fuel in

Answer 3

brain

Question 4

No glycogen stores in the

Answer 4

brain; gets it from bloodstrea.

Question 5

Uses ketone bodies when

Answer 5

body is starved or uncontrolled diabetes from the breakdown of fat.

Question 6

Where is the site for gluconeogenesis

Answer 6

Liver; a little in the renal cortex (kidney deals with excess lactate) and intestinal lining

Question 7

3 carbon precursosrs that are starting point

Answer 7

1. Lactate
2. Pyruvate
3. Glycerol

Question 8

Where do most gluconeogenesis reaction occur

Answer 8

in the cytoplasm

Question 9

3 irreversible steps are catalyzed by:

Answer 9

1. Hexokinase
2. Phosphofructokinase (Rate limiting, commited step)
3. Pyruvate kinase (converts PEP to pyruvate and makes ATP)

Question 10

In gluconeogenesis we need

Answer 10

NADH

Question 11

Part of converting Pyruvate to PEP occurs in the

Answer 11

mitochondria

Question 12

Pyruvate or _____usually initate gluconeogenesis

Answer 12

oxaloacetate

Question 13

Pyruvate usually comes from

Answer 13

skeletal muscle via Cori cycle or nitrogen groups from protein breakdown in skeletal muscle which is sent to liver as alanine

Question 14

Alanaine and pyruvate are

Answer 14

related; bc they only differ by the carbonyl group

Question 15

Oxaloacetate comes from

Answer 15

aspartate or TCA cycle; it is an alpha keto acid (amino acid relative, whos sister is aspartate)

Question 16

What shunts oxaloacetate from TCA cycle

Answer 16

malate shuttle

Question 17

Glycerol is also a starting point for

Answer 17

gluconeiogenis; it is the backbone for tryglycerides.

Question 18

No way to build glucose from

Answer 18

acetyl CoA; one exception is glycerol

Question 19

Kinaseses add

Answer 19

phosphate

Question 20

Phosphateases remove

Answer 20

phosphate

Question 21

Glucose 6 phosphatase

Answer 21

removes phosphate grouop from glucose. Bc once its phosphorylated it stays in the cell and we dont want this

Question 22

Hook on CO2 in one step to make oxalocetate and take it off in next step to make PEP

Answer 22

drive reaction forward. Production of CO2 gas drives reaction forward

Question 23

Pyruvate carboxylase is found in

Answer 23

mitochondria

Question 24

CO2 gets attached to pyruvate via

Answer 24

pyruvate carboxylase and goes back into cytoplasm via malate shuttle and is converted from oxaloacetate to PEP

Question 25

Any time you see additon of CO2 you know it needs which cofactor

Answer 25

biotin

Question 26

No transporter for

Answer 26

oxaloacetate; you have to convert it to malate via malate shuttle and convert it back to oxoacelatate

Question 27

Need to take off CO2 and add on phosphate group to make

Answer 27

PEP

Question 28

Use GTP as a phosphate

Answer 28

donor

Question 29

PEP synthesis can occur | PEP carboxykinase step

Answer 29

in cytoplasm or mitochondira

Question 30

Use ATP and ___carrier in the first step of gluconeogenesis

Answer 30

biotin

Question 31

Use GTP for second step of

Answer 31

gluconeogenesis

Question 32

Last step of glycolysis and first step of gluconeogenesis are very highly:

Answer 32

regulated.

Question 33

Biotin attaches

Answer 33

to epsilon amino group of lysine. Makes a flexible structure to move CO2 around the structure

Question 34

The mitochondria is very :

Answer 34

impermeable; very selective and has a lot of proteins

Question 35

What are the mitochondrial transporters

Answer 35

1. Pyruvate 2. PEP 3. Malate Not oxaloacetate!

Question 36

How are we going to decide whether or not we have to use the mallate shuttle to send oxalocetate out of the cell:

Answer 36

Depends on starting point and whether or not starting point is going to provide us with the NADH we need for gluconeogensis to occur

Question 37

If starting point is lactate (from muscle glycogen) the first step in the conversion of lactate back to pyruvate once it gets in liver cell provides us:

Answer 37

with NADH that we need to continue with gluconeogenesis; we dont need malate shuttle; we can convert oxaolocaetate to PEP in mitochondria using PEPCK. PEP transporter sends it to cytoplasm to go foward. Didnt have to borrow any reducing power from mitochondria!

Question 38

If its coming from alanine | protein breakdown

Answer 38

Alanine traseminates to pyruvate. No NADH is produced. Pyruvate goes to mitochondria, converts to oxaloacetate, which converts to malate. Send malate to cytoplasm through malate shuttle and convert it back to oxaloacetate (take off alcohol and make it a keto) using NAD+ and making NADH.

Question 39

If pyruvate is the main source of carbon:

Answer 39

the malate shuttle is used. By transporting malate to the cytoplasm, reducing power is also moved with it and NADH is produced as malate is converted to oxaloacetate. This NADH is needed for gluconeogenesis to proceed

Question 40

Malate needs ____to convert malate (from malate shuttle) to oxaloaceate

Answer 40

NAD+