Biochemistry 2 week 13

Question 1

Explain how the water soluble vitamins are characterised as

Answer 1

• Non B complex
  -B complex vitamins

Question 2

How are the B complex vitamisn grouped by

Answer 2

Grouped by function

Question 3

What vitamin is folic acid

Answer 3

Vitamin B9

Question 4

Is folic acid biologically active or inactive

Answer 4

inactive

Question 5

What is the natural form of folic acid + characteristic

Answer 5

-Folate- biologically inactive

Question 6

How can folate become active- folic acid

Answer 6

• It must be converted to tetrahydrofolate( THF) to become active via DHFR ( Dihydrofolate reductase)

Question 7

Where is folic acid stored + as what

Answer 7

Liver as polyglutamate

Question 8

Name foods rich in folate

Answer 8

• Citrus fruits, dark leafy greens, okra, broccoli, celery, corn

Question 9

What are the causes of folic acid deficiency

Answer 9

• Increased demand during pregnancy, lactation
  -Poor absorption
  -Alchohlism
  -Drugs

Question 10

What is the symptoms/effects of folic acid deficiency

Answer 10

• Megaloblastic anemia
  -Neural tube defects in fetus :spina bifida, anencephaly

Question 11

What is the function of THF (tetrahydrofolate) derivtes( in realtion to folic acid)- what does carry + needed for

Answer 11

• Carres one carbon unit
  -Needed for biosynthesis of serine, methionine, glycine, choline, purine bases

Question 12

What is Vitamin B9

Answer 12

Folic acid

Question 13

What vitamin is Cobalamin

Answer 13

Vitamin B 12

Question 14

Vitamin B12(Cobalamin) is required in humnas for what 3 main reactions?

Answer 14

• Remethylation of homocysteine forming methionine
  -Isomerization of methylmalonyl CoA forming succinyl COA
  -Thymidine synthesis

Question 15

Explain the structure of cobalamin (vitamin B12)

Answer 15

• Cobalt ion at the center of a corrin ring, coordinated by 4 pyrrole nitorgen atoms

Question 16

Name the sources of Vitamin B12 foods

Answer 16

• Liver, red meat, fishm eggs, dairy
  -Fortifed foods

Question 17

Explain the process of how vitamin B 12 ( Cobalamin ) is absorbed

Answer 17

Bound to proteins in food (as methylcobalamin or 5′-deoxyadenosylcobalamin)

Released in stomach by:

Gastric acid

Trypsin

Binds to intrinsic factor (IF)

IF is secreted by parietal cells of the stomach

Absorbed in the ileum (IF-B12 complex is taken up)

Transported in blood bound to transcobalamin II

Stored in liver

Question 18

What does deficiency of vitamin B12 lead to

Answer 18

Megoblastic anemia

Question 19

What is the effect/symptom of deficiency of vitamin B 12 (Cobalamin)

Answer 19

• Inceases in propionyl coA and methlymalonylcoA , this gets misincorporated into neuronal lipids instead of acteyl coA
  -Then this causes demyeination of spinal cord , brain, oerioheral nerves

Question 20

What vitamin can improve the anemia caused by B12 defieicny

Answer 20

-Folic acid , but it waint fix the neurological damage

Question 21

What vitamin is ascorbic acids

Answer 21

Vitamin C

Question 22

What is the active form of Ascorbic acid- VC

Answer 22

• Ascorbate

Question 23

Name both the passive and active way ascorbic acid VC is resorped

Answer 23

• Passive: Oral mucosa
  -Active: small intestine

Question 24

Name the 3 functions of ascorbic acid
2.Promotes

Answer 24

• Antioxidant
  -Promotes iron absoprtion
  -Coenzyme for collagen synthesis + noradrenaline synthesis

Question 25

What clinical conditionn does the deficency of ascorbic acid lead to

Answer 25

- Scurvy

Question 26

Why does the deficiency of ascorbic acid VC, lead to scurvy+ the other deficiency symptoms

Answer 26

- Due to decreased collagen hydroxylation, which leads to defective connective tissue -Decreased iron absoprtion which leads to microcytic or normocytic anemia

Question 27

What is vitamin C

Answer 27

Ascorbic acid

Question 28

What is Pyridoxine

Answer 28

Vitamin B6

Question 29

Name the 3 forms of pyridoxine( Vitamin B6)

Answer 29

- pyridoxine -Pyridoxal -Pyridoxamine

Question 30

What are all the forms of Pyridoxine (Vitamin B6) converted to

Answer 30

- Pyridoxal Phosphate ( PLP)

Question 31

Epxlain how the drug isoniazid for tubercolosis reacts with Pyridoxal Phosphate (PLP)

Answer 31

- Binds to PLP which leads to deficiency

Question 32

What are the symptoms of Vitamin C defiency

Answer 32

- Corkscrew hairs -Perifollicular hemorrhage -Easy brusing -Fatigue

Question 33

What is the function Pyridoxine VB6-active coenzyme for

Answer 33

PLP( pyridoxal phosphate )is a coenzyme involved the synthesis of heme, histamine, niacin, glutathione, neurotransmitters e.g serotonin, dopaminem epinephrine

Question 34

Name clinical features of Pyridoxine V-B6 deficiency

Answer 34

-Cheilosis -stomatitis -Sideroblastic anemia -seizures

Question 35

What vitamin is Thiamine

Answer 35

- Vitamin B1

Question 36

What is the active form of thiamine B1+ how its formed

Answer 36

Thiamine phyrophosphate(TPP) -Formed by a transfer of pyrophosphate grp from ATP to thiamine

Question 37

What is the functions of thiamine- what is TTP a coenzyme for - 4 | (ttp- thiamine pyrophosphate)

Answer 37

- Transketolase - Pyurvuate dehydorgenase -A-ketoglutarate dehydrogenase -Branches chain a keto acid dehydorgenase

Question 38

What are the causes of thiamine deficiency

Answer 38

- Chronic alchohlism -Malnutrition -Malabsoprtion syndromes -Vomiting

Question 39

Name 2 disorders( acute and chronid ) that resukts from chronic alchohlics as a symptom of thiamine deficiency

Answer 39

- Wernicke encephalopathy -Korsakoff syndrome

Question 40

Name the condition that results from severe thiamaine deficiency

Answer 40

Beriberi: -Dry and wet beriberi - ifantile beriberi

Question 41

Give a symptom of wernicke encephalopathy and korsakoff syndrom

Answer 41

-Wernicke encephalopathy: -Mental confusion Koraskoff syndrome -Memory loss , hallucinations

Question 42

Give a symptoms of the 3 diffeent types of beriberi

Answer 42

Dry- paralysis Wet- peripheral edema infantile-Vomiting seizures

Question 43

What vitamin is Niacin

Answer 43

Votamin B3

Question 44

What is the active forms of Niacin

Answer 44

-NaD+/NADH -NADP+/NADPH

Question 45

What does the active forms of Niacin - NAD+/NADH function as and involved in

Answer 45

Functions as an electron carrier in redox reactions Primarily involved in catabolic cellular processes

Question 46

What does the active forms of NADP+/NADPH dontate + involved in

Answer 46

Donates electrons in anabolic reactions -Involved in : -Oxidation-reduction reactions -Respiratoy burst -Glutathione reductase

Question 47

Where can niacin be found in

Answer 47

Meat especially liver. Cereals seeds

Question 48

What is clinical condition is result of niacin deficiency+ what it affects + symptoms

Answer 48

- Pellagra -Affects the skin, GI tract and CNS -symptoms: 3Ds -Dermatitis -Diarrhea -Dementia

Question 49

What is Vitamin B3

Answer 49

nIACIN

Question 50

What vitamin is riboflavin

Answer 50

Vitamin B2

Question 51

Name the active forms of riboflavin

Answer 51

- FMN -FAD

Question 52

Explain the functiosn of the ribflavin actove forms -what does it act as

Answer 52

- Act as cofactors for redoz enxymes

Question 53

Where can riboflavin - VB2 be found

Answer 53

- Meat, fish, eggs, milk , green veg, yeast

Question 54

Give 3 symptoms of ribflavin deficiency

Answer 54

-Dermatitis -Cheilosis -Gloossitis

Question 55

What is vitamin B7

Answer 55

Biotin

Question 56

What is pantothenic acid

Answer 56

Vitamin B5

Question 57

What is the function of Biotin v B7- What does it act as- what does it serve as

Answer 57

- Acts as a coenzyme in carboxylation reactions -Serves as a carrier of activated carbon dioxide

Question 58

What water soluble vitamin has rare deficiency

Answer 58

- Biotin- Bitamin B7 -Pantothenic acid- B5

Question 59

What are symptoms of Biotin- vitamin b7

Answer 59

- Dermatitis -Hair loss -Losso of appetitie

Question 60

What is the function of pantothenic acid VB5 -What is it a component of + part of

Answer 60

-Component of coenzyme A -Part of the acyl carrier protein (ACP)

Question 61

Where can pantothenic acid VB5 BE FOUND

Answer 61

eggs, liver yeast