lec 4: lipid metabolism

Question 1

fate of absorbed lipids

Answer 1

1. uptake by tissue.
2. utilization by tissue:
   -oxidation
   -conversion to glucose
   -formation of tissue fat
3. storage (adipose tissue as triacylglycerols)
4. secretion (sebaceous glands and lactating mammary glands).

Question 2

synthesis of TAG

Answer 2

lipogenesis

Question 3

destruction of stored fats to get energy

Answer 3

lipolysis

Question 4

promotes glycolysis

Answer 4

insulin hormone

Question 5

a hormone that stimulates glycogenesis (storage of glycogen)

Answer 5

insulin hormone

Question 6

insulin restricts this process

Answer 6

glycogenolysis (breaking down of glycogen)

Question 7

key enzyme of lipolysis

Answer 7

hormone sensitive lipase (HSL)

Question 8

a process which is important for providing energy when fasting

Answer 8

lipolysis

Question 9

synthesis of ketone bodies

Answer 9

ketogenesis

Question 10

examples of ketone bodies

Answer 10

acetoacetate - acetone - β-hydroxubutyrate

Question 11

only site of ketogenesis

Answer 11

liver

Question 12

liver enzymes that help in ketogenesis

Answer 12

HMG-CoA synthase (synthesis) & HMG-CoA lyase (breaking down)

Question 13

mainly derived from the oxidation of fatty acids

Answer 13

ketone bodies e.g. acetyl CoA

Question 14

a process that happens only in the mitochondria of extra hepatic tissues

Answer 14

ketolysis

Question 15

how does acetyl CoA help in the production of energy

Answer 15

by entering krebb’s cycle and as a result forming ATP

Question 16

a condition characterized by the elevation of the level of ketone bodies in blood

Answer 16

ketosis (ketogenesis > ketolysis)

Question 17

causes of ketosis

Answer 17

1. severe diabetes mellitus
2. prolonged fasting or starvation
3. high fat and low carbs in diet
4. prolonged administration of anti-insulin hormones especially in diabetic patients

Question 18

an organ responsible for the synthesis of cholesterol present in blood

Answer 18

liver

Question 19

key enzyme of cholesterol synthesis

Answer 19

HMG CoA reductase

Question 20

a high level of cholesterol in blood

Answer 20

hypercholesterolemia (higher than 240 mg/dl)

Question 21

causes of hypercholesterolemia

Answer 21

1. dietary causes rich in fats, carbs and cholesterol.
2. diabetes mellitus
3. hypothyroidism

Question 22

termed bad cholesterol

Answer 22

LDL

Question 23

termed good cholesterol

Answer 23

HDL

Question 24

important for reverse cholesterol transport

Answer 24

HDL

Question 25

lipoproteins that protect against atherosclerosis

Answer 25

HDL