Brainscape's Knowledge GenomeTM

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


See full index

Genes, molecules and cells (2) > Fat metabolism > Flashcards

Fat metabolism Flashcards

You may prefer our related Brainscape-certified flashcards:
Organic Chemistry 101 flashcards
1
Q

What type of molecules are lipids?

A

Hydrophobic organic molecules

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

What are 3 functions of a lipid?

A
  1. Bilayer
  2. Energy stores
  3. Intra cellular signalling
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What are the 2 main types of lipids?

A

Fatty acids

Glycerols (mono, di, tri)

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

What is the structure of a fatty acid?

A

Carboxylic acid with long chain hydrocarbon side groups

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

What species contain fatty acids?

A

Higher plants and animals

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

Where can fatty acids found in the body and how is it transported?

A

Plasma - serum albumin

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

How can fatty acids be used by tissues?

A

They are oxidised (liver & muscle) for energy

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

Can the brain metabolise fatty acids?

A

No - albumin cannot pass blood membrane barrier

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

What is the structure of a glycerol?

A

H2OC - HOC - H2OC

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

How are the tails attached to the glycerol?

A

Esterification

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

What Carbon number do the double bonds appear?

A

Carbon 9

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

Where are glycerols found? (2)

A

Fats and oils of plants and animals

Energy reserves - most abundant fatty acid

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

Where are fatty acids stored?

A

Adipose tissue

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

How are fatty acids stimulated to be released?

A

Hormone-sensitive lipase (removes fatty acid from C1 or C3)

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

How does hormone sensitive lipase become active? (2)

A
  1. Phosphorylated by a 3’-5’ cyclic amp protein kinase

2. Glucagon/epinephrine binds to the cells

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

How is hormone-senstive lipase deactivated?

A

High insulin or glucose causes dephosphorylation and inactivates

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

Where does glycerol released go?

A

To the liver via the blood

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

How does the Beta carbon (2) chain get broken down, where does this occur and what are the products?

A

Oxidation
Mitochondrial matrix
Acetyl CoA, NADH, FADH2

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

What is the equation for long fatty acid chain breakdown?

A

Fatty acid + CoA + ATP Acyl-CoA + AMP + PPi

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

What is used to prime long chain fatty acid breakdown?

A

Thiokinases

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

What is the long chain fatty acid breakdown driven by?

A

Exergonic hydrolysis of pyrophosphate - highly exergonic

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

What is the carnitine shuttle? (3)

A

A rate-limiting process
Fatty acids transfers its acyl-CoA on to carnitine
Transfers acyl group from there cytosol to the mitochondrial matrix via the outer mitochondrial membrane and inner mitochondrial membrane

23
Q

What is the purpose of acylcarnitine?

A

Transported into the matrix to allow free carnitine to go the other way

24
Q

What enzyme is used to remove carnitine and reattach CoA?

A

Transferase 1

25
Q

What enzyme is used to break up carnitine from CoA in the mitochondrial matrix?

A

Carnitine palmitoyltransferase 2

26
Q

How can the carnitine shuttle be inhibited?

A

Malonyl CoA means palmitate cannot be transferred

27
Q

How do we obtain carnitine? (2)

A

Diet

Synthesised from LYSINE and METHIONINE in the kidneys and liver

28
Q

What can cause carnitine deficiencies? (4)

A

Liver disease
Malnutrition
Pregnancy/burns victims
Haemodialysis

29
Q

How do short/medium chained fatty acids enter the mitochondria?

A

They do not need the carnitine shuttle and can cross the membranes freely

30
Q

What are the 4 sequences in the fatty acyl-CoA formation?

A
  1. Formation of a trans - alpha,beta double bond
  2. Hydration of the double bond
  3. NAD+ dependent dehydrogenation of the beta - hydroxyacyl-CoA
  4. Carbon alpha - Carbon Beta cleavage in thiolysis reaction with CoA to from acetyl-CoA and a new acyl-CoA
31
Q

What happens in the 1st sequence of fatty acyl-CoA formation and what does it produce? (3)

A

Formation of a trans alpha-beta double bond

  • via dehydrogenase by flavoenzyme acyl-CoA dehydrogenase
  • Produces FADH2
32
Q

What happens in the 2nd sequence of fatty acyl-CoA formation and what does it produce? (3)

A

Hydration of the double bond

  • Enoyl-CoA hydratase
  • forms 3-L-hydroxyacyl-CoA
33
Q

What happens in the 3rd sequence of fatty acyl-CoA formation and what does it produce? (3)

A

NAD+ dependent dehydrogenation of the beta-hydroyacyl-CoA

  • by 3-L-hydroxyacyl-CoA dehydrogenase
  • forms beta-ketoacyl-CoA, forms NADH
34
Q

What is the effect if acetyl-CoA on pyruvate carboxylase?

A

A positive allosteric effector

35
Q

What does each round of Beta-oxidation produce? (3)

A

NADH
FADH2
Acetyl CoA

36
Q

How much ATP is used in beta-oxidation?

A

129 ATP

37
Q

Where are ketone bodies formed?

A

Liver

38
Q

What are the 3 ketone bodies?

A
  1. Acetoacetate
  2. 3 - hydroxybutyrate
  3. Acetone
39
Q

What are ketone bodies important for?

A

Energy sources in heart and skeletal muscle

They do not need transport proteins

40
Q

Where does lipid biosynthesis occur?

A

Cytosol

41
Q

What is the first step of de novo fatty acid synthesis?

A

Transfer of acetate units from mitochondrial acetyl CoA to the cytosol

42
Q

How is acetyl CoA produced?

A

Oxidative carboxylation of pyruvate by pyruvate dehydrogenase

43
Q

What does the tricarboxylate transport system do? (3)

A
  1. The CoA portion of acetyl CoA cannot cross the inner mito-membrane
  2. OAA is reduced to malate by malate dehydrogenase
  3. Male is oxidatively decarboxylated to pyruvate by malic enzyme, then returned
44
Q

How does Acetyl-CoA form malonyl CoA

A

Carboxylation - biotin is the coenzyme

45
Q

How is palmitic acid formed? (7)

A
  1. Acetate is transferred from acetyl CoA to SH group of ACP
  2. This 2-C unit is transferred to the thiol group of a cysteine residue
  3. The ACP accepts a 3-C malonate unit it from lankly CoA
  4. The acetyl group on the cysteine residue condenses with the malonyl group on ACP
  5. The ketogenic group is reduced to an alcohol
  6. Water is removed to introduce a double bond between C2 and C3
  7. The double bond is reduced
46
Q

How many times is the palmitic cycle repeated?

A

5

47
Q

How is the palmitic cycle terminated?

A

Palmitoyl - S - ACP

48
Q

How can palmitate be elongated?

A

SER or mitochondria

49
Q

How are long chain fatty acids desaturated?

A

Desaturates - add cis - double bonds

50
Q

What are fatty acids stored in?

A

Triacylglycerides - glycerol phosphate is the initial acceptor

51
Q

What is the purpose of turning a fatty acid into a ketone?

A

Transport

52
Q

What is the main biosynthesis step of lipids?

A

Condensation of C2 units

53
Q

What do insulin and glucagon regulate?

A

Opposing pathways

Genes, molecules and cells (2) (14 decks)

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