Biochemistry week 6

Question 1

What organs play dominant roles in fuel metabolism

Answer 1

liver
adipose tissue
muscle
brain

Question 2

What do insulin and glucagon regulate + what supports the process

Answer 2

Energy metabolism
- epinephrine and norepinephrine supports the processes

Question 3

What is C pepttide essential for in relation to Insulin

Answer 3

• Essential for proer insulin folding

Question 4

What is insulin secretion regulated by

Answer 4

blood glucose levels

Question 5

Where is GLP-1- Glucagon-like-peptide-1 produced + function

Answer 5

-Produced in the intestines
-Inceases beta cell sensititivy to glucose

Question 6

Explain insulin affects on carbohydrate metabolism
-What it promotes

Answer 6

• Insulin promtes glucose storage, in the liver,muscle and adipose tissue

Question 7

Explain insulin effect in lipid metabolism
-What it inhibits
-What it activates

Answer 7

• Insulin inhibits hormone-sensitive lipase
  -Activates lipoprotein lipase

Question 8

Explain Insulin effect in protein metabolism
-What it stimulates
-What it promotes

Answer 8

• Insulin stimulates aminoacid uptake into cells
  -Promots protein synthesis

Question 9

What is glucagon secreted by

Answer 9

• a cells of the pancreatic islets of Langerhans

Question 10

What does glucagon oppose + what does it work alongside

Answer 10

Insulin
-Hormones such as epinephrine, norepinephine,cortisol, growth hromrone

Question 11

What is the primary stimulus from glucagon release

Answer 11

• Decreased plasma glucose concentration

Question 12

What else also stimulates glucagon release

Answer 12

Amino acids and elavted levels of epinephrine

Question 13

What is glucagons affect on carbohydrate metabolism
-What it promtoes

Answer 13

-Glycogenolysis and gluconeogenesis is promtoed

Question 14

What is glucagons effect on lipid metabolism
-Inhibition
-What it activates

Answer 14

• Inhibits fatty acid synthesis by phosphyorylating and inactivating acetyl coCarboxylase
  =Activates Hormone sensitive Lipase

Question 15

What is Glucagons effect on protein metabolsim

Answer 15

• Increases the uptake of amino acids by the liver

Question 16

What is the time period for the Absorptive State( Well-fed)

Answer 16

• 2-4 hours after eating a normal meal

Question 17

What is the Absorptive ( well fed state) characterised by

Answer 17

Increased plasma glucose, amino acids and TAGs

Question 18

What is the pancreatic response during the Absoprtive(well fed ) state

Answer 18

-Pancrease secretes more insulin and less glucagon due to elevated glucos elevels

Question 19

When does the fasting state begin

Answer 19

When no food is ingested after the absorptive period `

Question 20

What happens to the plamsa levels during fasting state

Answer 20

• Levels , of glucose, amino acids and TAG drop

Question 21

What happens during venous drainage

Answer 21

The liver recieves nutrients from the gut and pancreas via the hepatic portal vein

Question 22

During the absorptive state what does the liver uptake

Answer 22

• Carbohydrates
  -Lipids
  -Amino acids

Question 23

Explain what happens in carbohydrate metabolism during the well fed state
-What is increases(3)
-Decreased-Activated

Answer 23

-Increase in glucose phosphorylation
-Increase in glycogenesis
-Increased glycolysis
-Decreased glucose productiom
-Pentose Phosphate patwhay is activated

Question 24

What is the liver regulated by in the well fed state

Answer 24

• Various allosteric effectors that enhance or inhibit specific enzymes

Question 25

What is enzyme activity regukated by in the well fed state

Answer 25

- Phosphorylation

Question 26

What happens in fat metabolsim

Answer 26

1.Increased Fatty Acid syntheis: ACC( Acetyl coA carbocylase) is dephosphorylated, ctalauxing the formation of malonyl coA to acetlcoA -Increased TAC synthesis

Question 27

Explain what happens In adipose tissue in relation to energy storage: in Carbohydrate metabolism -In Fat metabolism

Answer 27

Carbohydrate metabolsim: - Increased glucose transport via GLUT 4 -Increased glycolysis and HMP Fat metabolism: -Fatty acids released

Question 28

Explain what happens in resting skeletal muscle in: -Carbohydrate metabolism -Fat metabolism -Amino acid metabolism

Answer 28

Carbohydrate metabolism -Increased glucose transprt via GLUT 4 -Increased glycogenesis Fat metabolism: - Fatty Acid releas Amino acid metabolism: -Increased protein synthesis

Question 29

What does the brain use as its main fuel + the name of transport and funvtion

Answer 29

- Glucose -Glut 1 , facilitates glucose entry in the blood brain barrier

Question 30

Explain what are the 2 main priorities in the fasted state + why

Answer 30

- To maintain plasma glucose, to sustain energy metabolism in the brain and red blood cells -To mobilize fatty acids , which provides enrgy for tissues

Question 31

What is the primary role of the liver in Fasting

Answer 31

- It maintains blood glucose levels through glycogenolysis and gluconeogenesis

Question 32

What are the metabolic pathwasy taking place in the liver during fasting + their effect

Answer 32

- Glycogenolysis- increases glucos e reelase -Gluconeogenesis- Fructose 1,6 bisphosphatase and PEPCK is activated gy glucagon to produce glucose -Fatty Acid oxidation: promotes B oxidation by -Ketogenesis: Which increases production of ketone bodies

Question 33

Exlain what the brain uses in early fasting + what maintains the blood glucose levels in the brain during early fasting

Answer 33

- Glucose as fuel -Hepatic gluconeogenesis from glucogenic precursors maintan blood glucose levels

Question 34

What happens in the brain during prolonged fasting( beyond 2 -3) weeks

Answer 34

- Plasma ketone bodues increase and replace glucose as the brains primary fuel soruce