Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Metabolic Pathways > Fat catabolism > Flashcards

Fat catabolism Flashcards

1
Q

How can we obtain fatty acids for catabolism ?

A
  • diet
  • stored fats (triglycerols - adipocytes)
  • newly synthesized fats (triglycerols that the body makes)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What are triglycerols?

A

These are 3 long chain fatty acid chains esterified to the glycerol backbone.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What are the major functions of triglycerols?

A
  • energy (~80%)

- more reduced, less hydrated than glycogen so can stockpile (adipocytes,better storage than glucose)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What happens in stage one of fat catabolism?

A

The long chain fatty acid is catabolised to form acetyl units in the form of acetyl co A

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What is the name of stage one of fatty acid catabolism?

Where does it occurs?

A

Beta-oxidation

Occurs in the mitochondrial matrix.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What happens in stage 2 of fat catabolism?

A

Acetyl groups are oxidised in the citric acid cycle.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What happens in stage 3 of fat catabolism?

A

Electrons are derived from oxidations of stages 1&2 pass to O2.
Via the mitochondrial respiratory chain ATP synthesis by oxidative phosphorylation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

How are TAGs stored?

A

within lipid droplets core of Tags and sterol esters.

surrounded by monolayer o phospholipids

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What is the surface of the adipocyte droplet coated in ?

A

Protein called perilipin - a protein which restricts untimely access to TAGs.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What receptors do adipocytes have?

A

adrenaline and glucagon - low blood glucose.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What do adrenaline and glucagon receptors activate on adipocytes?

A

Adenylyl cyclase - increase cAMP = activation of PKA

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What does protein kinase do?

A

It mobilises a number of different responses in the cell - it phosphorylates perilipins and other proteins to ‘open’ the lipid droplet.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What activity does PKA allow for?

A

3 cytosolic lipases including hormone sensitive lipase = degrade TAGs to liberate f.a

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What does the dissociated perilipin do ?

A

Stimulates the first lipase - allows access into lipid.

Tri - di.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What does the phosphorylated perilipin do?

A

It associated with the phosphorylated HSL - allowing access and convert tri to di.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What is the role of monoacylglycerol?

A

To hydrolyze monoacylglycerol.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

Where do the released fatty acids from the adipocyte go?

A

Into the blood bound to serum albumin. go to liver, skeletal muscle and enter via fatty acid transporter protein.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

What do all of the lipases do?

A

Hydrolyse ester linkages in tri/di and mono - acyl glycerol.

Liberating them

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

What happens when the fatty acids dissociate from the serum albumen?

A

They go through the fatty acid transporter protein into cytosol of cells which need energy.

20
Q

Where does beta oxidation fatty acid occur?

A

In the mitochondria, where fatty acid chains less than 14 carbon can enter.

21
Q

How are fatty acid chains longer than 14 carbon helped into the mitochrondria?

A

By activation and use of enzymes and transporter protein in inner mitochondrial membrane.

22
Q

What happens initially in fatty acid activation?

A

They are energised using fatty acid acyl-CoA synthetase isoenzymes.

23
Q

What is the role of fatty acyl coA synthetase?

A

It energises fatty acids - activating them.

- catalyses the formation of thioester linkage to yield fatty acyl CoA (ATP)

24
Q

Is fatty acyl CoA high energy compound more amenable to catabolism than fatty acids?

A

Yes

25
Q

Where is fatty acyl coA synthetase?

A

Outer mitochondrial membrane.

26
Q

How are fa longer than 14C transported into the mitochondrial matrtix?

A

Acyl-carnitine transporter called the carnitine shuttle

27
Q

How does fa acyl CoA join to the carnitine shuttle?

A

hydrolysed (more interactive)
attaches to the -OH of carnitine in outer mm
Catalysed: carnitine acyl-transferase-1

28
Q

What is the enzyme transfer involved in the mm?

A

Fatty acid group enzymatically transferred to intramitochondrial CoA
Catalysed: carnitine acyl-transferase-2

29
Q

What happens during the dehydrogenation-dehydrogenase beta oxidation pathway?

A

Removes 2H+ to FAD = FADH2

Double bond produced

30
Q

What are the 4 enzymes in the beta-oxidation pathway?

A
  • dehydrogenase
  • hydratase
  • dehydrogenase
  • thiolase
31
Q

What happens during the hydration - hydratase beta oxidation pathway?

A

H20 is added to form a double bond

1 H20 input

32
Q

What happens during dehydrogenation - dehydrogenase?

A

Removes 2H+ to NAD+ = NADH + H

1 NADH and H is formed.

33
Q

How many times are the 4 steps of the Beta oxidation carried out for the complete conversion of 16C palmitoyl-CoA to 8 molecules of Acetyl-CoA?

A

7 times

34
Q

How much energy is obtained from the beta oxidation of 16C palmitoyl CoA?

A

Lots - 7FADH2 and 7NADH - delivers electrons to respiratory chain and 8 acetyl COA to enter citric acid cycle.

35
Q

How many kilojoules does the beta oxidation pathway yield in comparison to glycolysis?

A

~9800kj/mol (1 palmitate to CO2 and H20)

~ 2380kj/mol (1 glucose)

36
Q

What configuration are double bonds usually in ?

A

Cis configuration (H atom same side)

37
Q

Which type of fatty acids have double bonds?

A

Unsaturated
mono - one
poly - more than one

38
Q

What two extra enzymes are needed to catabolise unsaturated fatty acids during beta oxidation?

A

Isomerase (cis - trans)

Reductase (Poly)

39
Q

Where are fatty acids stored in higher vertebrates?

A

adipocytes

40
Q

What is the name of the major storage fat?

A

Triacyglycerols

41
Q

What tissues use a lot of fatty acids for energy?

A

Liver, skeletal muscle

42
Q

Are fatty acids more or less reduced than glucose?

A

Much more reduced.

43
Q

Why are TAGs a better storage form of energy than glycogen?

A

Highly concentrated
Reduced
Anhydrous

44
Q

What part of the cell does fatty acid beta-oxidation take place?

A

Inside mitochondria.

45
Q

What does fatty acid activation involve?

A

Fatty acyl coA synthetase = Fatty acyl coA

Metabolic Pathways (13 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions