Medicine Sem 2 > Biochemistry 2 week 12 > Flashcards

Biochemistry 2 week 12 Flashcards

(48 cards)

Study These Flashcards
1
Q

Where is vitamin D synthesized

A

In the skin via sunlight

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

What is vitamin K synthesizewd by

A

Intestinal flora

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

What does the absorption of fat soluble viamins require

A

lipds, bile salts, and proper intestinal and pancreatic functiomn

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

Where are fat soluble vitamins stored

A

Liver and adipose tissue

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

Name the forms of vitamin A + characteristics/what they derived from or formed by

A

Retinol- Main form
Retinal-Derived from retinol
Retinoic acid-Formed by oxidaion of retinol
Carotenoids- converted into the body into retionol

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

Where is retinol stored and as what

A
  • In the liver as retinyl esters
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What is retinal derived from + essential for

A

-Derived from retinol
Essential for visual cycle

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

What is retinoic acid involed in

A

Gene regulation

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

What is retinol and retinalk essential for 3

A
  • reproduction, supporting spermatogenesis in the male + preventing fetal resorption in the female
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What are carotenoids + what are they used as
+ what are they converted into

A
  • Provitamins A
    -Converted into the body to retinol
    -Used as dietary supplements
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Explain the mechanims of retinoic acid action

A

Retinol → oxidized to retinoic acid

Retinoic acid binds to retinoic acid receptors (RARs) in the nucleus

RARs bind to DNA → regulate transcription of specific genes

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

Name all the main functions of Vitamin A

A

Vision
Epithelial maintenance
Reproduction

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

Explain vision(visual cycle) as a function of vA + what form used

A

Light → converts 11-cis-retinal to all-trans-retinal

Dissociates from opsin to generate a nerve impulse

Must regenerate back to cis form for continuous vision

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

Explain epithelial maintenance as a function of vitamin A + What form
What does it promote and support

A

Promotes differentiation and mucus secretion

Supports barrier defense against pathogens

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

What are the cuases of Vitamin A DEficiency

A

Malnutrition
Fat malabosprtion

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

What are symptoms of Vitamin A deficiency

A

Night blindness
Dry eyes( Xerophthalmia)
Bitot spots

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

What causes vitamin a toxicity

A
  • Excessive intake from supplements or medications
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

Wht are acute symptoms of vitamin A toxicity

A
  • Nausea, vomiting, headacheW
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

What are chronic symptoms of vitamin A toxicity

A

Dry skinm, scaling, alopecia

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

Explain the absorption and transport of vitamin A

Study These Flashcards
A
  • Dietary retinal esters are packed in chylomicrons
  • Chylomicrons remnants taken up by the liver
    When needed ;
  • Retinol is realised from the liver
  • Binds to retinol binding proteins ( RBP) and transthyretin
  • Delivered to target tissues
21
Q

What is vitamin d

Study These Flashcards
A

STEROL with hormone like function

22
Q

Name the different forms of vitamin D

Study These Flashcards
A

D2 - Ergocalciferol
D3- Cholecalciferol

23
Q

What are sources of vitamin D2

Study These Flashcards
A
  • Mushrooms
    -Fortifed food (milk, cereals )
    -Yeast
24
Q

What are sources of vitamin D3+ where its synthesised

Study These Flashcards
A

Fortified foods
-Fatty fish, liver, egg yolks, plants
-Synthesised in skin

25
What is active vitamin d CALLED
- Calcitriol
26
Name the main 3 functions of active vitamin D calcitriol
- Maintains blood calcium levels -Mechanism in intestine -Mechanism in bone
27
Explain how Calcitriol maintains blood calcium levels
- By : ↑ Calcium absorption from the intestine ↓ Calcium excretion by the kidneys ↑ Bone resorption (releases calcium when levels are low)
28
Explain the function of mechanism in intestine by active Vitamin D
Calcitriol binds cytosolic receptor → enters nucleus Binds DNA response elements → ↑ calbindin expression → ↑ Ca²⁺ absorption
29
Explain the function of calcitriol in mechanism of bone - what does it stimulate
Stimulates bone resorption and releases calcium
30
What is vitamin D deficiency in adults and children +name 2 other conditions
Children-Rickets Adults - Osteomalcia -Renal osteodystrophy -Hypopparathyroidism
31
Explain what rickets and osteomalcia entails/characteristics of Vitmin D deficiency disorders+ what they lead to
Rickets: Poor bone mineralization which leads to soft pliable bones Osteomalcia: Demineralisation of existing bone - which leads to fractures
32
What are the causes of Vitamin D Toxixity
- Excessive supplementation -Granulomatous diseases
33
What are symptoms of Vitamin D toxicity
Hypercalcemia Hypercalciuria - Increases calcium in urine
34
Name the main 3 functions Active vitamin d
Maintains blood calcium levels -Mechanism in intestine -Mechanism in bone
35
Name the only vitamin that can fully synthesize
- Vitamin D
36
Name the 3 forms of vitamin K 1. Where its found 2. What its produced by 3. Characteristics
-Phylloquinone (Vitamin K1): Found in plants Menaquinone (Vitamin K2): Produced by intestinal bacteria Menadione: Synthetic form, can be converted to K2
37
What is the function of vitamin K - what is required and needed for
-Required for hepatic synthesis of clotting factors: Factors II (prothrombin), VII, IX, X Protein C and Protein S (anticoagulant proteins) Needed for γ-carboxylation of glutamic acid residues → forms Gla residues
38
Name 4 food sources rich in vitamin K
- sPINACH -Kale -Broccoli -Cabbage (GREEN VEG AND FRUITS)
39
What is the cuases of vitamin K deficiency 4
- Liver failure -Fat malabsorption -Vitamin K anatgonists -Neonatal deficiency
40
Give a cinical feature of vitamin K deficency
- Hermorrhage : bleeding petechiae
41
What is the cause of Vitamin K toxiciy+ EFFECT in infants
- From high doses of menadione - Hemolytic anemia -Jaundice
42
How many and name the different forms of vitamin E
8 forms : tocopherols and tocotrienols
43
Name the most active + important form of Vitamin E
- a-Tocopherol
44
Name and explain the main function of Vitamin E
Antioxidant~: - Protects the cell membranes from free radical damage + protectsRBCs
45
Name other functions of Vitamin E -3
- Inhibits platelet aggegation -Inhibits cell proliferation and monocyte adheson -Inhibits certain enzymes: -Protein Kinase C, Phospholipase A2
46
Deficiency of which vitamin is uncommon
E
47
Wht are the causes of Vitamin E deficiency
- Fat malabsoprtion -Genetic defects in a-TTP(α-tocopherol transfer protein)
48
Give clinical features of Vitamin E deficiency
- Demyelination of spinal tracts -Hemolytic anemia -Muscle weakness
Medicine Sem 2
flashcards
Decks in class (91)
# Cards
Brainscape helps you reach your goals faster, through stronger study habits.
© 2026 Bold Learning Solutions. Terms and Conditions