Week 15: lipids and amino acids, integration of metabolism

Question 1

Where is the site major of amino acid degradation?

Answer 1

LIVER

Question 2

what happens to amino acids that are not used?

Answer 2

degraded

Question 3

What breaks down amino acids in the stomach and intestine for adsorption?

Answer 3

proteolytic enzymes

to di and tri peptides

Question 4

What absorbs amino acids?

Answer 4

intestinal cells and released into the blood for absorption by other tissues.

Question 5

Is there a storage form of amino acids?

Answer 5

no

Question 6

What is another way that the body generates free amino acids that it needs to deal with?

Answer 6

protein turnover

Question 7

What is protein turnover?

Answer 7

forms a very important part of the intercellular quality control process

Question 8

What is protein turnover important for?

Answer 8

rapid changed, damaged proteins have to be removed

Question 9

Amino acids contains a amide side chain but where else can N be found?

Answer 9

some amino acids also contain nitrogen in the side chain

Question 10

What is produced when amino acids are broken down?

Answer 10

NH3 (ammonia) & ammonium NH4+

Question 11

Is NH4+ toxic?

Answer 11

YES

Question 12

What can happen if there is a build up of Nitrogen compounds?

Answer 12

Leads to severe problems

needs a safe way of exerting excess Nitrogen

Question 13

What are you left with after removal of alpha-amino group (N)?

Answer 13

carbon skeleton

Question 14

What is the remaining carbon skeleton converted to after removal of alpha-amino group?

Answer 14

major metabolites intermediates

Question 15

What can the major metabolic intermediates then be converted to?

Answer 15

converted to glucose or oxidised in the TCA cycle

Question 16

What are the 2 categories of amino acids?

Answer 16

ketogenic AA

Glucogenic AA

Question 17

What can ketogenic AA be degraded to?

Answer 17

• Degraded to acetyl-CoA or acetoacetyl-CoA

- Give rise to ketone bodies or fatty acids

Question 18

What can glucogenic AA be degraded to?

Answer 18

• Degraded to pyruvate or TCA cycle intermediates

- Can be converted into phosphoenolpyruvate and then into glucose

Question 19

What 3 disorders that effects amino acid degredation?

Answer 19

Alcaptonuria
Maple syrup Urine disease
Phenylketonuria

Question 20

What type of amino acids are phenylalanine and tyrosine?

Answer 20

ketogenic and glucogenic AA

Question 21

What enzymes are degraded and blocked in maple syrup urine disease?

Answer 21

degradation of valine, isoleucine

blockage of leucine

Question 22

What enzymes are accumulates in Phenylketonuria?

Answer 22

phenylalanine in body fluids

Question 23

What enzymes are degraded and blocked in Alcaptonuria?

Answer 23

phenylalanine degraded

tyrosine blocked

Question 24

What is the prevention for maple syrup urine disease?

Answer 24

prevented by appropriate diet

Question 25

What is the therapy for phenylketonuria?

Answer 25

Low phenylalanine diet

Question 26

What happens when you have increased fat intake without appropriate energy expenditure?

Answer 26

increased number of adipocytes more fat in adipocytes obesity

Question 27

How do you control energy balance in the body?

Answer 27

- Genetically linked factors (protein messengers regulating appetite - Environmental factors (food abundance, fashionable foods)

Question 28

What are medical complications of being obese?

Answer 28

``` diabetes type 2 coronary heart disease hypertension stroke arthritis gall bladder disease ```

Question 29

What is fat required for?

Answer 29

- As an energy source | - For essential fatty acids (some polyunsaturated fatty acids can not be made by the body)

Question 30

What can a deficiency in essential fatty acids lead to?

Answer 30

membrane disorders, increased skin permeability, mitochondrial damage

Question 31

What are fat-soluble. vitamins stored in fat?

Answer 31

A, D, E , K

Question 32

What can happen id you don't have enough fat to store vitamins?

Answer 32

a secondary deficiencies can occur | efficiency in the vitamins

Question 33

What is the building block of steroids?

Answer 33

cholesterol

Question 34

Does cholesterol contain fatty acids?

Answer 34

Not usually | occur in natural fats

Question 35

What is the chemical structure of cholesterol?

Answer 35

rigid structure, multiple rings, in cell membranes | changes membrane properties

Question 36

What hormones is cholesterol an important pre-cursor for?

Answer 36

adrenocortical and sex hormones (progesterone, testosterone & oestrogen)

Question 37

What is another form of fats that are needed to try and digest a meal?

Answer 37

Triglycerides | triacylglycerols

Question 38

What is the main energy storage form in adipose tissue?

Answer 38

triglycerides

Question 39

Why are triglycerides used as storage in the adipose tissue?

Answer 39

-Very compact the acyl groups mean they are hydrophobic and don't require water so become very compact leads to a high energy yield per gram

Question 40

What is the features of a fatty acid structure?

Answer 40

mainly straight chains aliphatic (no rings) usually an even number of c atoms (2-120 or more) can be... saturated, unsaturated, polyunsaturated

Question 41

Do fatty acids usually have odd branched chains?

Answer 41

NO, usually even no. C atoms & no branches

Question 42

What configuration are double bonds normally in?

Answer 42

cis/trans

Question 43

What is the main products of fat digestion?

Answer 43

glycerol fatty acids monoglycerides (1 fatty acid + 1 glycerol)

Question 44

Where is glycerol readily absorbed into?

Answer 44

intestinal epithelial cells

Question 45

Where are fatty acids and monoglycerides absorbed into?

Answer 45

mucosal cells of intestine

Question 46

Where do short and medium length fatty acids enter after being absorbed into mucosal cells?

Answer 46

enter portal blood

Question 47

Where do long chain fatty acids and monoglycerides enter after being absorbed into mucosal cells?

Answer 47

Are re-synthesised to triacyglycerides in the mucosal cell

Question 48

What are the monoglycerides and fatty acids coated with to form?

Answer 48

layer of protein, phospholipid, cholesterol to form | Chylomicrons (now can facilitate transport)

Question 49

Where does the chylomicrons enter after synthesis

Answer 49

the lymph system then blood stream

Question 50

What happens to chylomicrons when it reaches muscle and adipose tissue?

Answer 50

- Attacked and cleaved by lipoprotein lipases | - Release free fatty acids

Question 51

What are the free fatty acids re-synthesised to in adipose tissue, for storage?

Answer 51

triacyglycerols

Question 52

What does the stored triacyglycerols get oxidised to to provide?

Answer 52

ENERGY | outcome depends on energy needs

Question 53

What is lipopolysis?

Answer 53

breakdown of lipids

Question 54

Can fatty acids be straight oxidised to generate energy?

Answer 54

NO, have to be converted to CoA derivatives.

Question 55

What is CoA role on fatty acid?

Answer 55

Forms as an activator, makes chains more active

Question 56

Does the fatty acid+ CoA--> acyl CoA require energy?

Answer 56

YES 2 ATP

Question 57

What does fatty acid bind to and what does it produce in order to be oxidised?

Answer 57

fatty acid+ CoA --> acyl-CoA

Question 58

Where does the fatty acid pick up the CoA?

Answer 58

cytoplasm must go to the mitochondria via carrier mechanism for it to be oxidised need to get to the matrix

Question 59

In the cytoplasm, fatty acids are transferred from acyl-CoA to what?

Answer 59

carnitine

Question 60

When Acyl-CoA transfers its fatty acids to carnitine, what does carnitine become?

Answer 60

Acyl-carnitine and enters the matrix

Question 61

When the acyl-carantine enters the mitochondrial matrix what can now occur?

Answer 61

beta oxidation

Question 62

What is produced in the the beta-oxidation (cycle)?

Answer 62

1 acetyl-CoA 1FADH2 1NADH+ H+ 1 fatty acyl-CoA, shortened by 2 carbon atoms

Question 63

When does a free (second) CoA enter the beta oxidation (cycle)?

Answer 63

The last step added to 3-ketoacyl CoA

Question 64

whhat are the 2 end products of the beta oxidation cycle?

Answer 64

acyl coA & acetyl CoA

Question 65

What is the fate of acetyl-coA after beta oxidation?

Answer 65

TCA cycle

Question 66

What produces more ATP, fatty acids or glucose?

Answer 66

FATTY ACIDS! 120ATP

Question 67

Give and example of what a triglyceride is?

Answer 67

e.g 3 stearic acids bonded to a glycerol

Question 68

What is glycerol?

Answer 68

the connector of the 3 fatty acids

Question 69

How do you breakdown glycerol?

Answer 69

glycerol kinase activates the glycerol-3-phosphate

Question 70

Where is the glycerol kinase present?

Answer 70

liver and kidney but not adipose tissue, skeletal and heart muscle

Question 71

What is glycerol-3-phosphate dehydrogenated to?

Answer 71

dihydroxyacetone phosphate | DHAP

Question 72

What can the DHAP be converted to (isomerism)?

Answer 72

G3P and enter glycolysis

Question 73

What is the process of making fatty acids?

Answer 73

lipogenesis | when more energy is taken in than needed

Question 74

Where does lipogenesis occur?

Answer 74

liver, kidney, mammary glands, adipose tissue & brain

Question 75

What is the excess of carbohydrate converted to?

Answer 75

fatty acids and triglycerides in the liver

Question 76

What are fatty acids then bound to in plasma? (excess of carbohydrate)

Answer 76

albumin

Question 77

Where do triglycerides go after carbohydrate is converted to triglycerides?

Answer 77

triglycerides formed in the liver are transported to adipose tissue by VLDL for storage

Question 78

What is VLDL?

Answer 78

very low density protein | transport triglycerides from liver to adipose tissue

Question 79

Is lipogenesis reductive or an oxidative process?

Answer 79

reductive | electrons are required

Question 80

What are the three states of your body in metabolism?

Answer 80

- Post prandial (after food) - Post absorptive (after digestion is complete) - Fast state (prolonged period of fasting)