Fat storage

Question 1

Where are triglycerides and cholesterol esters synthesised?

Answer 1

Smooth ER

Question 2

What makes up VLDL?

Answer 2

Triglyceride and cholesterol
Apoprotein B

Question 3

Where is apoprotein B synthesised?

Answer 3

Rough ER

Question 4

What is function of microsomal TAG transfer protein?

Answer 4

Add lipid components to Apoprotein B

Question 5

What is rate limiting for VLDL production?

Answer 5

FA *

Question 6

State process of Fatty Acid export?

Answer 6

1) Apoprotein B (ApoB) synthesised in rough ER
2) Lipid components (TG, Cholesterol esters) synthesised in smooth
ER
3) Microsomal TAG transfer protein adds lipid components to ApoB
4) Transported in vesicle to Golgi
5) ApoB is glycosylated
6) Glycosylated Apo’s with lipid components bud off golgi
7) Migrate to sinusoidal membrane of hepatocyte
8) Vesicles fuse with the membranes and VLDL is releasd

Question 7

Where is ApoB glycosylated?

Answer 7

Golgi apparatus

Question 8

Where does glycosated Apo with lipid component migrate to?

Answer 8

Sinusoidal membrane of hepatocyte

Question 9

What occurs if excess intake triglycerides?

Answer 9

1) Triglycerides reach liver
Accumulation

Question 10

What function of lipogenesis?

Answer 10

Produce triglycerides from acetyl-CoA subunits
Triglycerides used as energy reserve
Stored in adipose tissue

Question 11

What controls lvls of lipogenesis?

Answer 11

Insulin

Question 12

What is rate limiting step in lipogenesis?

Answer 12

Acetyl-coA to malonyl-coA

Question 13

What catalyses lipogenesis?

Answer 13

Acetyl CoA carboxylase

Question 14

Does lipogenesis increase or decrease during fasting?

Answer 14

Reduce
Hepatic glycogen stores depleted
Triglycerides broken down in adipocytes
Free FA released

Question 15

Is lipogenesis anabolic or catabolic?

Answer 15

Anabolic
Store

Question 16

Where are FFA oxidised for energy source?

Answer 16

Liver

Question 17

Where do lipids flow into liver from? (3)

Answer 17

1) Portal vein
2) Heptatic artery
3) Lymphatics

Question 18

In what form are lipids transported to liver? (4)

Answer 18

1) Triglycerides
2) Lipoproteins
3) Chlyomicron remnants
4) HDLs
5) FA bound albumin

Question 19

How are lipids uptaken into adipocyes?

Answer 19

Triglycerides can’t diffuse through cell membrane
1) Lipoprotein lipase breaks down triglycerides
2) Release free fatty acids
3) Fatty acids are lipophilic so diffuse through bilayer
4) Facilitated transport into the cells

Question 20

What are the 3 transport systems for fa into liver? (3)

Answer 20

1) Fatty acid binding protein (mitochondrial AST)
2) Fatty acid translocase (FAT)
3) Fatty acid transport polypeptide (FATP)

Question 21

Can triglycerides diffuse through membrane?
If not what can?

Answer 21

No
FFA can

Question 22

What enzyme breaks down triglycerides

Answer 22

Lipoprotein lipase

Question 23

What occurs do FA in adipocytes?

Answer 23

Re-esterified to triglycerides
Stored

Question 24

Where does FA move after adipocytes?

Answer 24

Hepatocytes

Question 25

Explain process movement from adipocytes to hepatocytes?

Answer 25

1) Sensitive lipase releases FFA 2) Hepatic lipase enables uptake FFA into hepatocytes

Question 26

What hormone releases FFA from adipocytes?

Answer 26

Hormone Sensitive lipase

Question 27

What enzyme enables uptake of FFA into hepatocytes?

Answer 27

Hepatic lipase

Question 28

In what form are lipids released from liver?

Answer 28

VLDLs

Question 29

How is energy released?

Answer 29

Oxidation

Question 30

Is demand or storage greater for lipds?

Answer 30

Storage

Question 31

List 3 functions of insulin?

Answer 31

Promotes fat storage in adipocytes Stimulates lipoprotein lipase (break TG allow FA diffuse) Reduces the activity of HSL (release FFA from adipo)

Question 32

Explain process insulin resistance?

Answer 32

1) Increased lipolysis– more circulating triglycerides 2) More free fatty acids for hepatocytes to take up 3) Increased glucose level means lipids are less used as an energy source

Question 33

How is the liver protected from large fatty acid influx?

Answer 33

Chylomicrons can bypass the liver Transported in lymphatic system

Question 34

Draw process fat moving inti adipocyte and into hepatocyte?

Answer 34

Question 35

What function of glucagon?

Answer 35

1) Stimulate liver break down glycogen- released in blood as glucose 2) Activate gluconeogenesis- conversion of aa into glucose 3) Break down stored triglycerides into FA

Question 36

What cells secrete glucagon?

Answer 36

Alpha cells of pancreas

Question 37

What cells secrete insulin?

Answer 37

Pancreatic beta cells

Question 38

Hypoglycemia results in.....g and i?

Answer 38

Alpha cells release glucagon Beta cells prod insulin inhibit

Question 39

Hyperglycemia results in....g and i?

Answer 39

Inhibits glucagon secretion Stimulate beta cells prod insulin

Question 40

Effect on blood sugar: glucagon and insulin

Answer 40

Glucagon- increases blood suger lvl Insulin- decrease blood sugar lvl