6: Biochemistry - Lipid catabolism Flashcards Preview

Gastrointestinal Week 1 2016/17 > 6: Biochemistry - Lipid catabolism > Flashcards

Flashcards in 6: Biochemistry - Lipid catabolism Deck (41)
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1
Q

What is the accurate name for a fat cell?

A

Adipocyte

2
Q

Increased fat intake without appropriate energy expenditure leads to (an increase / a decrease) in the number and fat content of adipocytes.

A

an increase

3
Q

Fat is an important source of ___.

A

energy

4
Q

What name is given to fatty acids which are required for body function but aren’t synthesised within the body itself?

A

Essential fatty acids

5
Q

Absorption of which important molecules is closely associated with fat absorption?

A

Vitamins (A,D,E,K)

6
Q

Give two examples of simple lipids.

A

Fatty acids

Triglycerides

7
Q

Which compound lipids transport fats in the plasma?

A

Lipoproteins

8
Q

Which group of lipids includes cholesterol** and hormones?

A

Steroids

9
Q

Lipids are (carbohydrates / hydrocarbons).

A

hydrocarbons

10
Q

Lipids are (soluble / insoluble) in water.

A

insoluble

11
Q

Are lipids hydrophilic or hydrophobic?

A

Hydrophobic

remember that they’re insoluble in water

12
Q

Which type of lipid is the primary storage molecule for fat?

A

Triglyceride

13
Q

What are the four main components of a triglyceride molecule?

A

Glycerol

3 fatty acids

14
Q

Molecules around a C=C double bond in fatty acids tend to be of a (cis / trans) configuration.

A

cis

15
Q

Essential fatty acids tend to be (saturated / unsaturated / polyunsaturated).

A

polyunsaturated

16
Q

What are the three main products of triglyceride digestion?

A

Fat is digested into:

glycerol

fatty acids

monoglycerides

17
Q

In which cells is glycerol absorbed in the GI tract?

Why can it be absorbed so early compared to fatty acids?

A

Intestinal epithelial cells

Glycerol is hydrophilic, fatty acids are hydrophobic

18
Q

In which cells are fatty acids and monoglycerides absorbed in the GI tract?

A

Intestinal mucosal cells

19
Q

After their absorption into intestinal mucosal cells, how are long chain fatty acids and monoglycerides prepared for transport in the blood?

A

Converted back into triglycerides

20
Q

Dietary fats (i.e digested fat - fatty acids and triglycerides) are transported in the blood as ___.

A

chylomicrons

cholesterol and protein are added on

21
Q

What is a chylomicron?

A

A transport vessel for dietary fat, made of protein and cholesterol

22
Q

Which enzyme cleaves chylomicrons to release the fatty acids and triglycerides it contains?

A

Lipoprotein lipase

23
Q

Which cells require the breakdown of chylomicrons to use the fatty acids and triglycerides?

Which cells use each product?

What is each product used for?

A

Adipose cells and Muscle cells

Adipose cells use the triglycerides

Muscle cells use the fatty acids

Triglycerides are STORED in adipose cells

Fatty acids are OXIDISED in muscle cells

24
Q

What happens to fatty acids in adipose cells?

A

Resynthesised into triglycerides

Stored

25
Q

What happens to fatty acids in muscle cells?

A

Oxidised for energy

26
Q

What is lipolysis?

A

Breakdown of lipids

27
Q

Which type of enzyme cleaves triglycerides to release fatty acids and glycerol?

A

Lipases

28
Q

Which emergency hormone regulates the effects of lipases?

A

Adrenaline

i.e fat is broken down for oxidation when it is needed, fight or flight

29
Q

Can fatty acids be oxidised immediately to generate energy?

Why?

A

No

They can’t pass through the mitochondrial membrane (hydrophobic) so they require a carrier

30
Q

How are fatty acids modified in the cytoplasm before their transport to the mitochondria for oxidation?

A

CoA added to form acyl-CoA

31
Q

How much ATP is required to add CoA to a fatty acid molecule?

A

2 ATP

32
Q

Which group transports acyl-CoA across the mitochondrial membrane?

A

Carnitine

technically CoA doesn’t pass across but why the fuq would we need to know that for mbchb medicine

33
Q

Each round of beta oxidation (oxidation of fatty acids in the mitochondria) generates electron ___ which can generate energy via the cytochrome system.

A

carriers

like NADH and FADH

34
Q

Oxidation of fatty acids with funny structures requires the catalysis of additional ___.

A

enzymes

35
Q

What byproduct is produced by the digestion of glycerol?

A

Ketone bodies

36
Q

What is the fate of acetyl-CoA generated from fatty acid oxidation?

A

Enters TCA cycle and is oxidised

37
Q

Which ketone usually deals with Acetyl-CoA in the TCA cycle?

A

Oxaloacetate

38
Q

During prolonged starvation, what happens to oxaloacetate?

A

It is consumed for gluconeogenesis

39
Q

What accumulates in the body of someone with diabetes or prolonged starvation?

A

Acetyl CoA

because no oxaloacetate is around to deal with it

40
Q

Acetyl-CoA is (acidic / alkaline).

A

acidic

41
Q

What is the condition caused by accumulation of acetyl-CoA in the body?

A

Ketoacidosis