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Flashcards in FA II Deck (58):
1

FA are made in the cytosol. If they need to be longer, we send them to the _____ or ____.

1. SEr
2. Mitochondria

2

In the blood, _____ must be tagged with albumin to keep them from clumping.

LCFA must be tagged with albumin to keep them from clumping.

3

There are 2 steps to FA degradation

1. FA movement inside the MT
2. B Oxidation

4

_____ and ____ can diffuse into the mitochondria. However, the outer MT membrane is impermeable to _____.

short chain FA and medium chain FA can diffuse into the membrane. However, the outer MT is not permeable to LCFA and VLCFA.

5

How do we combat the fact that LCFA are not permeable to the outer mitochondrial membrane?

ADD A ACYL COA

6

Step 1 Steps

As we have said, the outer membrane is not permeable to LCFA.

So:
1. FA--[Fatty acyl CoA synthetase]--> Fatty Acyl CoA
Fatty Acyl CoA can now cross the membrane into the intermembrane space. But now, there is a problem, it cannot cross the inner mT membrane

This required 1 ATP

2. So we want to remove the Co-A and add a carnitine. Adding a carnitine is its right of passage into the matrix.
Fatty Acyl CoA--[CPT-1: carnitine palmitoytransferase I]--> Fatty Acyl Carntine.

CPT-1 is the rate limiting enzyme in FA breakdown.

3. Fatty acyl carnitine can now move into the matrix via CACT (carnitine shuttle)
Carnitine shuttle is an antiport. It moves Fatty acyl carnitine into the matrix and moves carnitine out

4. Fatty acyl carntine is now acted upon by CPTII to remove the carnitine and change it back to Fatty acyl coA

7

Shortcut of phase 1

To get past outer MT membrane:
1. add a coA
To get past the inner MT membrane
2. add a carnitine
Once inside
3. remove carnitine and add a coA again.

8

Where is fatty acyl coA synthetase located?

on the outer membrane

9

What is CPT-1

Carnitine palmitoytransferase will remove the coA and add a carnitine. Located in the inter mT membrane

10

What is CACT

CACT is the carnitine shuttle that will transport fatty acyl carnitine to the mitochondrial membrane.

It is an antiport and remove the build up of carnitine from inside the matrix

11

What is CPT-II

Removes carnitine and adds coA

12

Where is CPT-1 located

intermembrane space

13

Where is CACT located

inner mt membrane

14

where is CPT-II located

inner mt membrane

15

What is the rate limiting enzyme in FA breakdown?

CPT-1

Carnitine palmitoy transferase!

16

Our typical saturated FA have how many carbons

an even number
16-20

17

What do we make in B oxidation?

1. Acetyl Co-A- taken into the TCA cycle
2. NADH--> move electrons to complex 1
3. FADH2--> move electrons of coQ

18

B oxidation makes 3 things: what is it?

1. Acetyl CoA
NADH
FADH2

19

What is the first substrate of B-oxidation?

Fatty Acyl Co-A

20

Acroynm for B oxidation

OHOT
oxidation
hydration
oxidation
thiolysis

21

Oxidation

ACAD (acyl coA dehydrogenase) will oxidize Fatty acyl coA

FADH2 is made

22

Why is ACAD important

it causes many disease

23

Hydration

NADH is made

24

2nd oxidation step

Acetyl CoA is released

25

The only enzyme to remember in B oxidation is

ACAD

Acyl Co-A Dehydrogenase

26

B oxidation occurs where?

mT matrix

27

Types of ACADS

4 types
1. SCAD
2. MCAD
3. LCAD
4. VLCAD

28

______ is the type of ACAD that causes the most diseases

MCAD

medium chain acyl coA dehydrogenase

29

What happens if we have a FA with a odd number of carbons?

Phase 1- same.

However, if we break it down, we will be left with a 3 carbon compound known as PROPIONYL COA.
So what do we do?

PROPIONYL COA.--[propionyl coA carboxylase]--> methylmelonyl coA (a 4 carbon compound)

methyl melonyl coA will eventually become succinyl coA and go into the TCA cycle

30

3 carbon compound created when oxidizing odd numbered FA

propionyl coA

31

What would we do to proponiol coA

carboxylate it via propionyl coA and make a 4 carbon compound called methmalonyl coA

32

What happens to the methyl-melonyl coA made?

it will eventually become succinyl coA and enter the TCA cycle

33

What happens if we are trying to break down unsaturated FA?

We will need new enzymes. We metabolize it until a DB is reached

1. Reducatases will reduce the DB
2. Isomerase will move the disrupted bond so it can be degraded by a regular enzyme

34

How are VLCFA--> LCFA

perixisomal B oxidation
once you get to 20 carbons, it undergoes normal oxidation

35

When you are undergoing B oxidation in the perixoisome, do you make energy?

NO. You do not make any NRG.

High energy electrons are transferred to O2 to make H202.

36

If you undergo B oxidation in the perixisome, wont it create a build up of H2O2?

No. A catalase will then convert the H2O2 to water and O2.

37

Key difference in peroxisomal B oxidation and regular?

During the 1st oxidation stage, ACAD is not used.
It will use Acyl CoA Oxidase, which still creates FADH2, but not for NRG. electrons are transferred to O2 to make H2O2

38

What enzyme is used instead of ACAD in perixosomal B oxidation?

Acyl CoA Oxidase

39

Zellweger syndrome

patient has a defect in the generation of peroxisomes. Thus, they cannot break down VLCFAs

40

MCAD deficiency

People with MCAD deficiencies cannot break down medium chain FA.
It leads to a secondary deficiency in carnitines because we rare excreting a lot of it out. We are soaking up alot of our carnitines.
Person will have elevated levels of ammonia
Pts will depend on glucose for NRG.
This is preventative

41

Ketone bodies are made when we have a lot of _______

acetyl coA

42

What begins the creation of ketone bodies?

Ketone bodies are made when we have a problem with insulin signaling (people with DB or on a ketogenic diet). Glucose is not getting into the cells; so we cannot use it for energy.

As a result, we start to use our fat stores. Fat is broken down and is made into acetyl coA

We then get a build up of acetyl coA, which will then make ketone bodies.

43

Where are ketone bodies made/

ONLY the mT matrix of the LIVER!!!!

44

Characteristics of ketone bodies

1. acidic
2. water-soluble

45

3 types of ketone bodies

1. acetoacetate
2. acetone
3. beta- hydroxybutryate.

46

What can use ketone bodies?

1. brain
2. muscles
3. kidneys

47

Can RBCs use ketone bodies?

NO!

48

How can we create acetoacetate?

2 acetyl coAs combine--> acetoacetyl CoA-->
HMB CoA--> Acetoacetate

49

few hours after fasting

1. blood glucose
2. glycogen stores
3. gluconeogenesis

50

1 day after not eating

B oxidation of TAGS

51

3 days after eating

1. begin to make ketone bodies
2. proteins in muscles break down
3. glycerol from TAGS and proteins enter glucogonic AA enter gluconeogenesis can provide NRG to the brain and RBC

52

1-2 weeks after

brain will use ketone bodies

53

2-3 months

death

54

When can we get physiological ketosis?

slight elevation of ketone bodies

occurs when fasting, pregnant, excercising, babies and ketogenic diet

55

Pathological ketoacidosis

Glucagon/insulin ratio is increased and we favor FA breakdown

56

in diabetic ketoacidosis

ketones are being formed and they drop your blood pH big time

57

What does CACT stand for

Carnitine acylcarnitine translocate (CACT) shuttles fatty acyl carnitine into the matrix

58

why do we die from ketone bodies

blood pH drop