Interconversion

Question 1

How is Glucose stored in liver, and released

Answer 1

As G6P, and dephosphorlyated to form Glucose. G6P can be further reacted to form glycogen

Question 2

How is TAG stored in adipose tissue

Answer 2

FFA (binded to albumin) in blood and TAG binded to chylemicron(–> VLDL in liver) is transported to WAT

TAG in VLDL is broken into FFA and glycerol

While the latter one is sent to liver while FFA becomes FA Co-A

Glucose is converted to DHAP then G3P, which combines with FA Co-A to form TAG

Question 3

How abt in Liver?

Answer 3

It is converted to liver lipid directly

Question 4

How is excess amino acid stored

Answer 4

It is nvr stored

Question 5

So how to cope with them

Answer 5

They are removed by deamination where their amino group is removed as urea and carbon skeleton as carbs

Question 6

How can Glucose used to release ATP

Answer 6

It forms pyruvate then acetyl Co-A and enters TCA cycle then ETC

Question 7

How can Lipid release ATP. Where?

Answer 7

At liver, skeletal muscles and Cardiac muscles

FFA undergoes Beta oxidation to release ATP, NADH and Acetyl Co-A

Acetyl Co-A forms Ketone body which travels in blood and can be converted to Acetyl Co-A

NADH enters ETC

Question 8

how to release energy by Amino acid

Answer 8

In deamination, the carbon skeleton of Alanine is used to synthesize pyruvate, which can be converted to glucose via gluconogenesis or enter TCA cycle

Question 9

How to convert Glucose to TAG (iN LIVER)

Answer 9

Glucose forms acetyl Co-A, which is converted into cholesterol and FA by citrate

FA combines with glycerol to form TAG

Question 10

TAG –> Glucose (In liver)

Answer 10

FA forms Acetyl Co-A which enters TCA cycle or export as ketone bodies.

Acetyl Co-A forms oxaloacetate to make PEP/pyruvate , which then forms glucose by gluconegenesis

Glycerol form glucose via gluconogenesis

Question 11

Amino acid–>Carbs

Answer 11

Via deamination

Become G6P then glucose via gluconogenesis

Form acetyl Co-A and forms glucose via oxaloacetate then PEP

Question 12

Carbs –> amino acid

Answer 12

Glucose enters TCA cycle to form oxaloacetate and a-ketoglutarate

Oxaloacetate can form TATA SCGP (Trp, Asp, Tyr, Asn, Ser. Cys, Gly, Phe

a-Ketoglutarate –> Glu–> Glu, Pro, Arg

Question 13

How to form nucleotides

Answer 13

Glu can be used to form purines

Asp and Asn (derived from oxalacetate) can form pyramidines

Question 14

How to replenish TCA intermediates

Answer 14

Oxaloacetate (In liver and kidney)

Pyruvate +HCO3-+ ATP
–> (pyruvate carboxylase)
Oxaloacetate + ADP+ Pi

In heart and skeletal muscle
Phosphoenolpyruvate +NAD(P)H
–> (carboxykinase)
Oxaloacetate +GTP

In most eukaryotes and bacteria
Pyruvate + HCO3- +NAD(P)H
–> (malic enzymes)
Malate + NAD(P)

Question 15

Why we have to regulate the catabolism and anabolism

Answer 15

It is wasteful to simultaneously synthesize and degrade some substances

Question 16

How to regulate

Answer 16

1. Some antagonistic pathway may share some metabolites but they will have at least 1-2 steps using different enzymes, which serves as the site for regulation
2. Different sites of reaction

Question 17

What is purpose of metabolic homeostatis

Answer 17

To control balance between subtrate need and subtrate availabilty

Question 18

How does Metabolic homeostatis work

Answer 18

1. Conc of nutrients or metabolites in blood affect the rate of their usage and stored in different tissues
2. The body detects the change in level, hence hormones are sent to different tissues to tell their target tissue about the physiological state of the body and the nutrient supply or demand
3. The CNS will use neural signals to control metabolism in tissues directly or via the release of hormones

Question 19

What does insulin do interms of fuel mobilization

Answer 19

It promote storage of fuels, like Glucose to glycogen and TAG while inhibit the mobilization of fuel in these stores.

It promote protein synthesis from amino acid

It promote use of glucose

Question 20

What does glucagon do. What tissue does it NOT working on

Answer 20

1.Stimulate formation of glucose from glycogen, lactate, glycerol and amino acid.

2.Stimulate the release of FFA to release energy

It has no effect on skeletal muscle

Question 21

Name 2 more Insulin-countering hormones except glucagon.How are they secreted

Answer 21

Cortisol and epinephine. By neuronal signals