Fat Digestion

Question 1

Aliphatic meaning

Answer 1

Open chains of carbon atoms rather than rings

Question 2

Source of basic lipids

Answer 2

From diet (e.g. meat), as well as our own bodies synthesising it

Question 3

Energy yield from 1 mol of fat

Answer 3

120 mol ATP - 16kJ/mol

Question 4

Energy yield from 1 mol glucose

Answer 4

32 mol ATP - 36kJ/mol

Question 5

How fats are separated out, considering that enzymes exist in an aqueous solution and can’t get into fat?

Answer 5

Emulsification with bile salts, derived from the liver. Allows mixing in water. Fat breaks into micelles.

Question 6

Enzymes involved in breaking the ester linkages between fatty acids and glycerol

Answer 6

Lipase & colipase. First diacylglycerol is formed, then monoacylglycerol, etc.

Question 7

Where fat is sent for processing

Answer 7

Muscle, adipose tissue, liver, etc. Fatty acids can’t be used to fuel the brain.

Question 8

Roles of phospholipids

Answer 8

Biomembrane structure & bio-signalling

Question 9

Roles of sphingolipids

Answer 9

Biomembrane structure and bio-signalling

Question 10

Role of cholesterol

Answer 10

Used with bile salts in energy and used as steroid hormones in bio-signalling

Question 11

Role of triglycerides

Answer 11

Energy

Question 12

Role of fatty acids

Answer 12

Biomembrane structure, bio-signalling and energy

Question 13

Where is the alpha carbon on fatty acid chains

Answer 13

In the carboxyl group; it is the carbon attached to the carbon with a double bond to oxygen

Question 14

Where is the beta carbon on fatty acid chains

Answer 14

The carbon adjacent to the alpha carbon

Question 15

Amount of double bonds in stearic acid and length of the molecule

Answer 15

No double bonds and 18 carbons in total, including the carboxyl group

Question 16

To what degree are animal fats saturated

Answer 16

Mainly saturated

Question 17

To what degree are tropical oils of palm and coconut saturated

Answer 17

Mainly saturated

Question 18

To what degree are some common vegetable oils saturated, such as olive and canola?

Answer 18

Mainly monounsaturated

Question 19

To what degree are the majority of vegetable oils saturated? For example, corn oil and sunflower oil

Answer 19

Mainly polyunsaturated, w6 linoleic

Question 20

What weight of glycogen associates with what weight of water?

Answer 20

1g glycogen with 2g water

Question 21

What is triacylglycerol converted to in the small intestine? And why?

Answer 21

Fatty acid and monoacylglycerol. Two fatty acids are removed. This is to remove them into micelles. Simultaneous digestion by lipase and colipase, then stabilized by bile salts.

Question 22

What cells absorb mycelles from digestion of fats by lipase?

Answer 22

Epithelial cells

Question 23

What is formed in the golgi apparatus of epithelial cells when triacylglycerides combine with proteins?

Answer 23

Chylomicrons

Question 24

Describe what happens to chylomicrons after leaving epithelial cells

Answer 24

They enter lymph capillaries and get transported away by lacteals.

Question 25

What happens to fat during excess

Answer 25

Lipogenesis; acetyl-coa to triacylglycerol, stored in adipose tissue. Fatty acyl coa and glycerol-3-phosphate are turned into triacylglycerol

Question 26

What organ are fatty acids used in

Answer 26

Muscle

Question 27

Where is glycerol sent to and why

Answer 27

The liver and adipose tissue

Question 28

Role of LPL (lipoprotein lipase) in chylomicrons

Answer 28

Fatty acids released from triacylglycerides, mainly sent to muscles