Lipid Catabolism

Question 0

How is acyl-carnitine transported from cytoplasm to mitochondria?

Answer 0

Acyl-carnitine shuttle

Question 1

How are fatty acids activated?

Answer 1

Conversion to acyl-coA (requires 2ATP)

Question 2

What is the substrate for beta oxidation?

Answer 2

Acyl-coA

Question 3

Products of each beta oxidation cycle

Answer 3

• 1 acetyl coA
• 1 fatty acyl coA (shortened by 2 carbon atoms)
• complete me

Question 4

What type of fatty acids cannot be synthesised by the body?

Answer 4

Polyunsaturated fatty acids

deficiencies can lead to membrane disorders, increased skin permeability, mitochondrial damage

Question 5

Fat soluble vitamins

Answer 5

ADEK (often stored in body fat)

-if fat intake or absorption is inadequate, secondary deficiencies can occur

Question 6

What are compound lipids?

Answer 6

Lipids associated with other functional groups

Question 7

Fatty acids, triglycerides and waxes are what kinds of lipids?

Answer 7

Simple lipids

Question 8

Which molecules are the main energy storage form in adipose tissue?

Answer 8

Triglycerides

high energy yield per gram

Question 9

More common to have an even or odd number of C’s in fatty acids?

Answer 9

Even (usually straight as well)

Question 10

Polyunsaturated

Answer 10

Several double bonds

Question 11

Are double bonds usually in cis or trans formation?

Answer 11

cis (same plane)

Question 12

Most common fatty acid in humans

Answer 12

Palmitic acid (16C)

Question 13

How many carbons in stearic acid?

Answer 13

18

Question 14

How many carbon atoms in oleic acid?

Answer 14

18 but also has a double bond, cheekay ;)

Question 15

Body can only make double bonds in fatty acids up to (?) carbons away from carboxyl end

Answer 15

9

Question 16

Essential fatty acids?

Answer 16

Polyunsaturated fatty acids that cannot be synthesised by the body

Question 17

Lineolic acid

Answer 17

18:2

Question 18

Fatty acids-nomenclature

Answer 18

Carboxyl group is C1
C adjacent is alpha
C furthest away is omega

Question 19

Fatty acids with up to (?) atoms are liquid at room temperature?

Answer 19

8

Question 20

What do double bonds do to the melting point?

Answer 20

They lower it

Question 21

Animal fats contain mostly what fatty acids?

Answer 21

Palmitic and stearic

Question 22

Why is absorbing fatty acids more complicated than absorbing glycerol?

Answer 22

Glycerol is an alcohol

Fatty acids are hydrophobic

Question 23

Short and medium length fatty acids

Answer 23

enter portal blood
(longer chain FA and monoglycerides-resynthesised to TG. This TG is then coated with a layer of protein, phospholipid and cholesterol to form a chylomicron, enter lymph and then blood)

Question 24

Lipoprotein lipases

Answer 24

Chylomicrons

Question 25

Hormone sensitive lipases

e.g. adrenaline sensitive

Answer 25

Cleavage of stored fat

Released free fatty acids and glycerol when energy is needed

Question 26

Why are fatty acids linked to CoA

Answer 26

To activate them (requires 2ATP)

This generates an acyl-coA

Question 27

Difference between acetylcoA and acyl-coA?

Answer 27

Acetyl coA contains 2 carbons, acyl coA contains an undefined number of carbons (any fatty acid attached to a coA)

Question 28

Where does the linking of fatty acids to coA occur?

Answer 28

In the cytoplasm of cells

Question 29

Where does oxidation of fatty acids occur?

Answer 29

Mitochondrial matrix

Question 30

Function of the carnitine shuttle?

Answer 30

Transports fatty acids from cytoplasm to mitochondria
(fatty acid from acyl-coA transferred onto carnitine to form acyl-carnitine)
CoA molecules never transported across the membrane

Question 31

Where does beta oxidation take place?

Answer 31

The mitochondrial matrix

Question 32

How many steps in beta oxidation?

Answer 32

4
Products are acetyl coA and a new acyl coA (shortened by 2 carbon atoms)
1 FADH2
1 NADH+ plus H+

Question 33

Where is glycerol-3-phosphate absent from?

Answer 33

Skeletal muscle, adipose tissue and the heart