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CBA- 1 > Biochemistry > Flashcards

Biochemistry Flashcards

1
Q

what is width of plasma membrane

A

7-10 nm wide

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2
Q

what is the chemical composition of plasma membrane

A

43% lipids
49 % proteins
8 % carbohydrates

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3
Q

what are the types of lipids in cell membrane

A

Phospholipids (Lecithin & Cephalin)
Glycosphingolipids (Cerebrosides & Gangliosides)
Cholesterol

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4
Q

what is significance of lecithin in cell membrane

A

Lecithin is composed of units of choline, phosphoric acid, fatty acids and glycerol. … Without lecithin, the cell membranes would become less fluid, thus less permeable.

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5
Q

what is the significance of cephalin in cell membrane

A

Cephalin plays a role in membrane fusion. Fusion is the process by which two initially distinct lipid bilayers merge their hydrophobic cores, resulting in one interconnected structure.

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6
Q

what is the function of ganliosides in cell membrane

A

Gangliosides is a component of the plasma membrane that modulates cell signal transduction events.
The functions of gangliosides as specific determinants suggest its important role in the growth and differentiation of tissues as well a
s in carcinogenesis.

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7
Q

what is the significance of cholesterol in cell membrane

A

Cholesterol provides stability to the plasma membrane by limiting the movement of the phospholipids.
cholesterol in the cell membrane is to maintain stability, anchor other molecules.
Cholesterol acts as a bidirectional regulator of membrane fluidity because at high temperatures, it stabilizes the membrane and raises its melting point, whereas at low temperatures it intercalates between the phospholipids and prevents them from clustering together and stiffening.

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8
Q

write a short note on the fatty acids in cell membrane

A

They are also major component of cell membrane. 50% of fatty acid groups are saturated. The other half contains unsaturated and polyunsaturated fatty acids.
Oleic acid is the most abundant unsaturated fatty acids in animal membranes.
The degree of unsaturation determines the fluidity of the membranes.

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9
Q

which types of proteins form the cell membrane

A

Integral or intrinsic proteins
Peripheral or extrinsic proteins
Trans-membrane proteins
(span the whole width )

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10
Q

what is integral membrane protein and write about its signifiance

A

An integral membrane protein (IMP) is a type of membrane protein that is permanently attached to the biological membrane.
IMPs include transporters, linkers, channels, receptors, enzymes, structural membrane-anchoring domains, proteins involved in accumulation and transduction of energy, and proteins responsible for cell adhesion. Common examples are Insulin receptors, Glycophorin, Rhodopsins. Band-3 proteins etc

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11
Q

what is peripheral membrane protein and its significance in cell membrane

A

Peripheral membrane proteins are membrane proteins that adhere only temporarily to the biological membrane with which they are associated.
Peripheral enzymes participate in metabolism of different membrane components, such as lipids (phospholipases and cholesterol oxidases).

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12
Q

what is transmembrane protein and write about its significance

A

A trans membrane protein (TP) is a type of integral membrane protein that spans entirely the cell membrane to which it is permanently attached. Many trans membrane proteins function as gateways to permit the transport of specific substances across the membrane.

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13
Q

what are the major functions of membrane proteins

A 
Transport
Enzymatic activity
Signal transduction
Cell-cell recognition
Intercellular joining
Attachment to the cytoskeleton and extracellular matrix (ECM)
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14
Q

which carbohydrates are present in cell membrane

A

Glycoproteins

Glycolipids

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15
Q

what is glycosylation

A

The carbohydrate is attached to the protein in a posttranslational modification. This process is known as glycosylation.

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16
Q

what is the significance og glycoprotein and give a detailed example

A

Glycoproteins are also often important integral membrane proteins, where they play a role in cell–cell interactions. One example of glycoproteins found in the body is mucins, which are secreted in the mucus of the respiratory and digestive tracts. The sugars when attached to mucins give them considerable water-holding capacity and also make them resistant to proteolysis by digestive enzymes.

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17
Q

what are glycolipids and write about their significance

A

Glycolipids are lipids with a carbohydrate attached by a glyosidic (covalent) bond. Their role is to maintain the stability of the cell membrane and to facilitate cellular recognition, which is crucial to the immune response and in the connections that allow cells to connect to one another to form tissues. They include glyceroglycolipids and glycosphingolipids.

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18
Q

what is glycocalyx and write about its significance

A

The glycocalyx, is a glycoprotein and glycolipid covering that surrounds the cell membranes. This viscous coating consists of several carbohydrate moieties of membrane glycolipids and glycoproteins, which serve as backbone molecules for support. Generally, the carbohydrate portion of the glycolipids found on the surface of plasma membranes helps these molecules contribute to cell–cell recognition, communication, and intercellular adhesion.

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19
Q

how are caveolae formed

A

The caveolae are formed by the curving inward of the inner leaflet of the plasma membrane an integral protein named caveolin forces the formation of caveolae which are involved in the membrane transport and rigidity

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20
Q

how are rafts formed and write about their structure

A

The rafts are made by the clustering of sphingolipid with cholesterol in the outer monolayer of the plasma membrane. The rafts appear to have receptors and signaling proteins.

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21
Q

write about the clinical significance of cell membrane

A

ALZHEIMER’S DISEASE: Oxidative stress in brain results in alterations in phospholipids that comprise the cell membrane and disrupts the functions of effected brain cells.
CYSTIC FIBROSIS: Defect in calcium ion channels for the unclear reasons in excess production of fluid in lungs

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22
Q

what are ion channels and describe their types

A

Ion channels are transmembrane channels, pore like structures composed of proteins”.

All channels have gates & are controlled by opening
and closing.

TYPES:

Ligand gated channels:
In this a specific molecule binds to a receptor and opens the channel.

Voltage gated channels:
These channels open or close in response to changes in membrane potential.

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23
Q

write a short note on simple or passive diffusion

A

It depends on concentration gradient of a particular substance across the membrane
The solute passes from higher concentration to lower concentration till equilibrium is reached
The process neither requires any carrier protein nor energy

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24
Q

write a short note on facilitated diffuision

A

It is similar to passive diffusion in that the solutes move along the concentration gradient.
But it differs from passive diffusion in that it requires a carrier protein or transport protein.
Energy is not required.

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25
Q

write a short note on active transport

A

It occurs against a concentration gradient
Energy is required
40% of the total energy requirement in a cell is utilized for active transport system
Carrier or transport proteins are needed

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26
Q

write a short note on uniport

A

This system involves the movement of certain substance across the plasma membrane singly and independently of any other substance
The transporter involved is called uniporter

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27
Q

write a short note on symport

A

This system involves the movement of two substances across the membrane together & in the same direction
The transporter involved is called symporter

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28
Q

write a short note on antiport an give an example

A

Also called counter transport
This system involves the movement of two different substances simultaneously, but in two different directions
Example: Efflux of 3 Na + ions to cell exterior & a simultaneous influx of 2 K+ ions

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29
Q

what are the mechanisms for transport of macromolecules

A 
The mechanism of transport of macromolecules such as proteins, hormones, immunoglobulins, LDL, and even viruses takes place across the membrane by two independent mechanisms
 Exocytosis
 Endocytosis 
 Phagocytosis = “cellular eating”
 Pinocytosis = “cellular drinking
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30
Q

what is exocytosis

A

In exocytosis, transport vesicles migrate to the membrane, fuse with it, and release their contents. Many secretory cells use exocytosis to export their products.

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31
Q

what is endocytosis

A

In endocytosis, the cell takes in macromolecules by forming vesicles from the plasma membrane. Endocytosis is a reversal of exocytosis, involving different proteins

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32
Q

describe the types of endocytosis

A

Phagocytosis (cellular eating): Cell engulfs particle in a vacuole
Pinocytosis (cellular drinking): Cell creates vesicle around fluid
Receptor-mediated endocytosis: Binding of ligands to receptors triggers vesicle formation

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33
Q

describe the activity of sodium potassium pump and its significance

A

Transports sodium from inside to outside the cell and at the same time pumps K+ from outside to inside the cell.
Maintain sodium and potassium concentrations
Establishing a negative electrical voltage inside the cells

Complex of two separate globular proteins
 subunit, with a molecular weight of about 100,000.
β subunit, with a molecular weight of about 55,000.

It has three receptor sites for binding sodium ions on the portion of the protein that protrudes to the inside of the cell.
It has two receptor sites for potassium ions on the outside.
The inside portion of this protein near the sodium binding sites has ATPase activity

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34
Q

write about the primary active transport of calcium

A

Calcium is actively transported from inside to outside the cell by calcium pump.

Energy is obtained from ATP by the catalytic activity of ATPase.

Present in the sarcoplasmic reticulum of muscle cells and the mitochondria of all the cells.

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35
Q

write about the primary active transport of hydrogen ions

A

In the gastric glands of the stomach
Involved in the formation of hydrochloric acid
In the late distal tubules and cortical collecting ducts of the kidneys
Hydrogen ions are secreted from the blood into the urine

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36
Q

what is the biochemical importance of carbohydrates

A

Glucose is major metabolic fuel for mammals & is precursor for synthesis of all other carbohydrates in the body
Glycogen for storage
Ribose & deoxyribose in nucleic acids
Galactose in the lactose of milk (milk sugar)
Carbohydrates occurs in cell membranes as glycoproteins & glycolipids
Present in lipoproteins
Diseases related to CHO metabolism include galactosemia, lactose intolerance, glycogen storage diseases, diabetes mellitus

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37
Q

what are carbohydrates

A

Poly hydroxy aldehydes
or
Poly hydroxy ketones

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38
Q

describe classification of carbohydrates

A 
Monosaccharides
 Disaccharides
 Oligosaccharides
 Polysaccharides
 Derived carbohydrates
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39
Q

write a short note on monosaccharides

A

Monosaccharides are simple sugars
Can not be further hydrolyzed
A carbonyl group (aldehyde or ketone) & several hydroxyl groups
Eg. Glucose, fructose, galactose
General formula (CH2O)n ( n= 3 or some larger number

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40
Q

write a short note on disaccharides

A

Those sugars which yield two molecules of the same or different monosaccharides on hydrolysis
The two monosaccharides are linked by a glycosidic bond
Eg. lactose, sucrose, maltose, isomaltose, trehalose
General formula Cn(H2O)n-1

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41
Q

what are glucose dimers

A

Maltose α 1-4 linkage…..isomaltose α 1-6 linkage…..trehalose α 1-1 linkage…..all are glucose dimers

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42
Q

write a short note on oligosaccharides

A

Those sugars which yield 3 to 10 monosaccharides on hydrolysis
Monosaccharides are joined to each other covalently through O- glycosidic bonds or linkages
E.g α dextrins ( polymer of eight glucose molecules)

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43
Q

write a short note on polysaccharides

A 
Those sugars which yield more than 10 molecules of monosaccharides on hydrolysis
General formula   (C6H10O5)n  
Further divided into
    Homopolysaccharides (homoglycans)
    Heteropolysaccharides (heteroglycans)
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44
Q

what are homopolysaccharides

A

Polymer of same monosaccharide units

Eg . Starch, glycogen, dextrin, dextran, cellulose

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45
Q

what are heteropolysaccharides

A

Polymer of different monosaccharide units
Eg. Mucopolysaccharides ( GAGs)
Glycoconjugates, Mucilages

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46
Q

write a short note on complex/derived carbohydrates and their examples

A

Derived from carbohydrates by various reactions
Eg. Oxidation products, reduction products, amino sugars, deoxy sugar

Oxidation… gluconic acid glucaric acid ascorbic acid……. Reduction… polyhydroxy alcohols-glycerol….. Amino sugar ….glucosamine….. Deoxysugar… deoxyribose

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47
Q

monosaccharides can be classified into

A

aldoses

ketoses

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48
Q

aldoses can be classified into ——– according to number of carbon atoms

A 
triose     (3 C atoms) (glyceraldehyde)
tetrose   (4 C atoms) (erythrose)
pentose  (5 C atoms) (ribose)
hexose   (6 C atoms) (glucose, galactose, mannose)
heptose (glucoheptose)
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49
Q

ketoses can be classified into ——— according to number of carbon atoms

A 
tritulose (dihydroxy acetone)
tetrulose   (4 C atoms) (erthrulose
pentulose  (5 C atoms) (ribulose)
hexulose   (6 C atoms) (fructose)
heptulose (sedoheptulose)
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50
Q

what are disaccharides and give some examples

A

A disaccharide consists of two monosaccharides.

Glucose + Glucose Maltose + H2O

	Glucose + Galactose	                      Lactose + H2o

  Glucose + Fructose		                 Sucrose + H2o
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51
Q

what is fisher projection

A

straight chain representation

3D structure of stereoisomers can easily be drawn and represented in 2D

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52
Q

what is harworth projection

A

simple ring in perspective

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53
Q

what are conformational representation

A

chair and boat configuration

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54
Q

what are hemiacetal and hemiketal

A

aldehyde and alcohol from hemiacetal

ketone and alcohol form hemiketal

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55
Q

write a short note on D-glucose

A

Found in fruits, corn syrup, and honey.
An aldohexose with the formula C6H12O6.
Known as blood sugar in the body.
The monosaccharide in polymers of starch, cellulose, and glycogen.

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56
Q

write a short note D-fructose

A

Is a ketohexose C6H12O6.
Is the sweetest carbohydrate.
Is found in fruit juices and honey.
Converts into glucose in the body.

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57
Q

write a short note on D - galactose

A 
An aldohexose C6H12O6
Not found free in nature.
Obtained from lactose, a disaccharide
A similar structure to glucose except for the 
	–OH on C4.
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58
Q

how are glyosidic bonds formed

A

Glycosidic bonds are formed by the enzymes glycosyl transferases that use nucleotide sugars as substrate

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59
Q

write a short note on maltose

A

Maltose, a cleavage product of starch (e.g., amylose), is a disaccharide with an a(1® 4) glycosidic link between C1 - C4 OH of 2 glucoses.
It is the a anomer (C1 O points down).

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60
Q

write a short note on sucrose

A

common table sugar, has a glycosidic bond linking the anomeric hydroxyl of glucose & fructose, the linkage is α (12)

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61
Q

write a short note on lactose

A

milk sugar, is composed of galactose & glucose, with β (14) linkage from the anomeric OH of galactose

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62
Q

what is inversion phenomenon

A

In free form fructose occurs in pyranose form which is strong levorotatory
Rotation is reversed & process is called inversion phenomenon
Product of sucrose hydrolysis ( fructose) is called invert sugar

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63
Q

write a short note on reducing and non-reducing sugars

A

Sugars having atleast one free aldehyde or keto group in their structure are Reducing sugars
Those which do not have any free active group (aldehyde or keto) are known as Non-reducing Sugars
All monosaccharides & disaccharides are reducing except sucrose
A non-reducing sugar can be hydrolyzed using dilute hydrochloric acid. After hydrolysis and neutralization of the acid, the product may be a reducing sugar

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64
Q

what are structural and storage polysaccharides

A

Storage polysaccharides contain only α-glucose units. Important ones are starch & glycogen

Structural polysaccharides contain only -glucose units. Important ones are cellulose and chitin. Chitin contains a modified -glucose unit

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65
Q

write a short note on starch

A

Starch is a storage compound in plants, and made of αD-glucose units
It is a homo-polymer of glucose made up of two components: amylose and amylopectin.
Starch is 15-20% amylose and 80-85% amylopectin
It is also non-reducing (because no potential aldehyde group

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66
Q

describe amylose

A

Amylose – a straight chain structure formed by α 1→4 glycosidic bonds between α-D-glucose molecules.
The amylose chain forms a helix or coiled structure

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67
Q

describe amylopectin structure

A

Amylopectin-a glucose polymer with mainly α -(14) linkages, but it also has branches formed by α -(16) linkages

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68
Q

what is the action of enzymes on starch

A

Salivary & pancreatic amylases (α-amylases) hydrolyze starch into
Maltose
Maltotriose
α- dextrins

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69
Q

write a short note on starch

A

Structural polysaccharide
It is an unbranched polymer of -D-glucose mainly present in plant kingdom
Consists of large number of glucose residues joined to each other through (1→4) linkages
Cellulose is made up of repeating disaccharide units called cellubiose
Cellubiose has same structure as maltose, but unlike maltose it has (1→4) glycosidic linkage

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70
Q

write about significance of cellulose

A

Cellulose is important in our diet because it
Provides fiber & bulk to the food
Serves to satisfy appetite
& Assists with digestive movements in the small and large intestine
Humans can not digest cellulose because they lack the enzyme cellulase to hydrolyze the (1→4) glycosidic bond

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71
Q

write a short note on glycogen

A

Homo-polymer of α D-glucose
Storage polysaccharide also known as animal starch
Present in liver & muscles
Resembles amylopectin but it is more compact
A glucose polymer with mainly α -(14) linkages, but also has branches formed by α -(16) linkages
Glycogenesis
Glycogenolysis

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72
Q

what are dextrins

A

Intermediate products in the hydrolysis of starch by acids or enzyme amylase
Each dextrin molecule consists of 8 α D-glucose residues showing mostly α -(14) linkages in addition to α -(16) linkage at each of branching site
Sweet in taste

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73
Q

what are dextrans

A

Dextrans homo-polymer of α D-glucose residues
Showing mostly α -(16) linkages in addition to (12), (13) & (14) linkages
Used in medicine as plasma substitute or plasma extender in the treatment of hypovolemic shock

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74
Q

what are lipids

A

Heterogeneous group of organic compounds”

Soluble in organic solvents but in soluble in water

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75
Q

what is the biomedical importance of lipids

A 
High energy dietary constituent
Lipoprotein (lipid transporter)
Structural components (plasma membrane)
Protective covering to internal organs
Production of hormones
Fat soluble vitamins
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76
Q

lipids are classified into

A

simple lipids
compound lipids
derived lipids

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77
Q

simple lipids are derived into

A

fats

waxes

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78
Q

simple fats are

A

neutral fats/ triglycerides

esters of fatty acids with glycerol

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79
Q

what are waxes and their types

A 
Esters of fatty acids with long chain alcohols
1.   True Waxes
Bees Wax, Lanolin, 
Spermaceti
2.   Others Waxes
Cholesterol Esters,
Vitamins A & D
Lipase can not hydrolyze waxes
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80
Q

compound lipids include

A 
phospholipids 
sulfolipids
gangliosides
glycolipids
lipopolysaccharides 
lipoproteins
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81
Q

phospholipids include

A

glycerophospholipids
(lecithin, cephalin, plasmalogens)

sphingophospholipids
(sphingomyelins)

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82
Q

derived lipids include

A 
diglyceride
fatty acids 
alcohols
cholesterol
fat soluble vitamins
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83
Q

what are fatty acids and their characteristics

A

“Aliphatic Mono-carboxylic Acids”

Double bonds are always spaced at 3-Carbon intervals from each other

  Numbered from carboxyl end
             CH3-R-COOH
   Even number of carbon atoms
   Unbranched
   Saturated or unsaturated
   Cis or Trans
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84
Q

what are the properties of enzymes

A 
Protein catalysts
 ( except Ribozymes)

Increases the velocity of chemical reactions

Not consumed during reactions they catalyze

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85
Q

what are catalysts

A

Speeds up chemical reactions in living organisms by decreasing the energy needed to start the reaction (activation energy)

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86
Q

describe the location of enzymes

A

Enzymes are localized in specific organelles within the cell

This isolation separates reaction substrates or products from other competing reactions

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87
Q

what are characteristic of enzymes

A

Enzymes are highly specific, interacting with one or few substrates & catalyzing only one type of chemical reaction

Enzyme catalyzed reactions are faster than un catalyzed reactions
Each enzyme molecule is capable of transforming 100-1000 substrate molecules into product each second.

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88
Q

what is turnover number

A

The number of molecules of substrate converted to product per enzyme molecule per second is called the turnover number

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89
Q

what are the mechanisms of enzyme catalysis

A

Lock & key model

Induced fit model

90
Q

what is lock and key hypothesis

A

Enzyme and substrate both are rigid structures

Both fit in each other just like a specific key fix in a lock

91
Q

what is induced fit model

A

Enzyme will induce change in its shape when substrate comes close to fit in it

92
Q

what are the classifications of enzymes

A

site of action (intracellular/extracellular)

source of enzymes (plants, animals)

chemical composition (simple/conjugated)

type of reaction (hydrolase, oxidase, dehydrogenase)

type of substrate(proteinn, carb, lipids)

93
Q

what is composition classification of enzyme

A

simple enzymes (composed completlyof protein)

complex enzymes (composed of protein plus non-protein part)

holoenzymes are complex enzymes

protein component is called apoenzyme

94
Q

what is holoenzyme

A

active enzyme with its non-protein component

95
Q

what is co-factor

A

non protein part

usually metal ion of iron and zinc

96
Q

what is co enzyme and its types

A

Non-protein part is a small organic molecule

Coenzyme A & NAD+

Transiently associated coenzyme = Co-Substrate
Permanently associated coenzyme= Prosthetic Group

97
Q

what are the factors that affect enzyme activity

A 
Enzyme concentration
Substrate concentration
Temperature
pH
Product  concentration
Presence of cofactors, coenzymes & prosthetic group
Inhibitors
98
Q

what is the effect of enzyme concetration on rate of reaction

A

directly proportional

99
Q

what is the effect of substrate concetration on rate of reaction

A

Enzyme reaction is directly proportional to the substrate concentration

Substrate concentration α velocity of reaction

When the maximum velocity is achieved the increasing concentration of substrate does not further increase the reaction rate

100
Q

what is the effect of temperature on rate of reaction

A

Optimum temperature

Humans … 35 C- 40 C

The reaction velocity increases with temperature until a peak velocity is reached

Further elevation of the temperature results in a decrease in reaction velocity
(denaturation of the enzyme)

101
Q

what is the effect of ph on rate of reaction

A

Enzymatic activity is maximum at optimum pH

Optimum pH is different for different enzymes
e.g Pepsin —pH 2

Extreme changes in pH may denature enzyme

The reaction rate is decreased

102
Q

what is the effect of product conc on rate of reaction

A

Excess of products may lower the enzymatic reaction by occupying the active site of the enzyme

Reaction slows down or stops

103
Q

what is the effect of inhibitors on rate of reaction

A

Enzymes are proteins which can be inactivated by the agents known inhibitors & this process is known as enzyme inhibition

Inhibitors of enzymes generally resemble particular enzymes substrate(s)

Many therapeutic drugs are some type of enzyme inhibitor

104
Q

what is optimum ph for enzymes in humans

A

Optimum pH of most enzymes is 4-9
Exceptions:
Digestive enzymes in stomach (pH 2)
Digestive enzymes intestine (pH 8)

105
Q

what are inhibitor and their types

A

Enzyme inhibitors inhibits the enzyme activity

Two types
Reversible inhibition (noncovalent bonds)
                          Competitive
 		          Noncompetitive (mixed) 
		          Uncompetitive
Irreversible inhibition (covalent bonds)
106
Q

what are reversible competitive inhibitors

A

These are chemicals that resemble an enzyme’s normal substrate and compete with it for the active site

Increasing the conc. of substrate can reverse this type of inhibition

107
Q

what are reversible non-competitive inhibitors

A

Do not enter the active site, but binds to another part of the enzyme change its shape & alters the active site
Increasing the conc. of substrate cannot reverse this type of inhibition

108
Q

what is non-competitive inhibition

A

An uncompetitive inhibitor binds to the enzyme substrate complex but not to free enzyme

The effect of an uncompetitive inhibitor can not be overcome by high concentrations of the substrate

Result in the destruction or modification of an essential amino acid required for enzyme activity

Suicide inhibitors

109
Q

what are allosteric enzymes

A

Allosteric means “occupy different sites”
In addition to active sites these enzymes possess other sites where certain reagents called effectors ( modifiers & modulators) can bound
Non-covalent linkages
e.g cAMP, cGMP
Allosteric enzyme + effector = change in 3 dimensional structure of enzyme

Inhibition or activation of enzyme activity

110
Q

what are nucleic acids

A

These are non protein nitrogenous substances made up of a monomeric unit called a nucleotide.

111
Q

what are nucleic acids and its types

A

These are non protein nitrogenous substances made up of a monomeric unit called a nucleotide.

DNA and RNA

112
Q

what are nucleic acids types

A

DNA and RNA

113
Q

what are the bases and nucleosides

A 
adenine (adenosine)
guanine (guanosine)
cytosine (cytidine)
uracil (uridine)
thymine (thymidine)
114
Q

what is nucleoside

A

base plus sugar

115
Q

what the nucleosides in DNA

A

ATGC

116
Q

what are the nucleosides in RNA

A

AUGC

117
Q

what are purines and examples

A

two rings structure

AG

118
Q

what are pyrimidine

A

one ring structure

TCU

119
Q

what is the significance of phosphate group

A

Used to form phosphodiester linkage between 5’ and 3’ carbons of adjacent nucleotides in order to form polynucleotide chains.

120
Q

number of hydrogen bonds between two nucleotides

A

AT 2
AU 2
GC 3

121
Q

structure of DNA is

A

double stranded helix

122
Q

describe detailed structure of DNA

A

In crystalline DNA the bases are separated by 0.34nm and each base is rotated 36 in relation to the previous base .
The helical structure repeats at interval of 3.4nm .
Therefore there are 10 base pairs in each completed helix .
The helix is 2nm in diameter .
The molecule shows a minor groove and a major groove .
These grooves wind along the molecule parallel to the phosphodiester linkage .
These grooves serves to accommodate proteins which binds with specific nucleotide sequences without disturbing the base pairing of double helical DNA molecule

123
Q

what are the types of DNA replication

A

conservative

semi-conservative

124
Q

write a short note on DNA replication

A

DNA in the chromosomes replicates itself every cell division .
Maintains correct genetic information .
Two strands of DNA unwind .
Each strand acts like a template .
New bases pair with their complementary base.
Two double helixes are formed that are copies of original DNA .

125
Q

why is DNA called genetic material

A

Present in all cells and virtually restricted to the nucleus .

The amount of DNA in somatic cells (body cells) of any given species is constant (like the number of chromosomes) .

The DNA content of gametes (sex cells) is half that of somatic cells.

In cases of polyploidy (multiple sets of chromosomes) the DNA content increases by a proportional factor .

The mutagenic effect of UV light peaks at 253.7nm. The peak for the absorption of UV light by DNA .

126
Q

why do we need both DNA and RNA

A

DNA holds all the genetic information/instructions for the proteins produced in a cell so why do we need RNA.

It is bcause DNA holds all the genetic information, this means it is Extremely important.

If DNA is damaged in any way, the coding sequence can change and a mutationwill arise that will potentially influence the particular protein and perhaps the whole cell or organism.

If DNA ventured into the cytoplasm to give instructions for protein synthesis it would be vulnerable to damage from chemicals, UV radiation and other mutagens.

RNA acts as a massenger. Damage to mRNA will not permanently affect function of the cell as the DNA template is undamaged.

127
Q

what are the steps involved in DNA replication

A

Identification of site of origin of replication

Unwinding the DNA molecule

Formation of replication fork

Initiation and elongation

Formation of replication bubble and ligation

128
Q

describe the process of unwinding in DNA molecule

A

Replication of DNA begins at a sequence of nucleotides called the origin of replication.

An enzyme called helicase unwinds the dsDNA helix and single-stranded binding proteins (SSBP) react with the ssDNA and stabilize it.

At the same time, DNA gyrase relieves the strain that unwinding causes on the molecule by cutting, winding and rejoining DNA strands.

Under an electron microscope the unwound section looks like a “bubble” and thus is known as the replication bubble.

129
Q

describe step of the formation of new stands in DNA replication

A

DNA polymerase III is the major enzyme involved in DNA replication.
It adds nucleotides to the 3’ end of a pre-existing chain of nucleotides thus generating a new complementary strand of DNA, but it cannot initiate a nucleotide chain.
An RNA polymerase called primase is needed to start a new nucleotide chain.
Primase constructs an RNA primer (sequence of about 10 nucleotides complementary to the parent strand) which DNA polymerase III can then add nucleotides to.
The unwound DNA exposes two parental strands of DNA which are antiparallel. This means they are orientated in different directions and must be replicated by different mechanisms.
The leading strand elongates towards the replication fork (in the direction of unwinding) by the simple addition of nucleotides to is 3’ end by DNA polymerase III.

The lagging strand must elongate away from the replication fork. It is synthesized discontinuously as a series of short segments called Okazaki fragments. When DNA polymerase III reaches the RNA primer on the lagging strand, it is replaced by DNA polymerase I, which removes the RNA primer and replaces it with DNA. DNA ligase then attaches and forms phosphodiester bonds.

Since each new strand is complementary to its old template strand, two identical new copies of the DNA double helix are produced during replication.
In each new helix, one strand is the old template and the other is new synthesised, therefore replication is said to be semi-conservative.
The two DNA molecules rewind into the double-helices, then each double-helix is coiled around histone proteins and further wrapped up to form separate chromatids (still joined by a common centromere).
The two chromatids will become separated in the cell division process to form two separate chromosomes

130
Q

what is transcription

A

Process of RNA synthesis from DNA template is called transcription.

131
Q

write a detailed note on transcription of DNA

A

Process of transcription begins when a section of DNA (a gene) unwinds and the bases separate exposing two single strands of DNA with unpaired bases.
One of these strands act as a template for the formation of an mRNA molecule (it is transcribed).
Individual nucleotides of RNA align with the exposed bases on the DNA template according to base pairing rules. And nucleotides are added to 3’ end of growing RNA molecule.
The formation of the mRNA molecule is catalysed by the enzyme RNA polymerase.
This molecule is actually referred to as pre-mRNA. It is complementary to the template strand but requires some post-transcriptional modification.
Post-transcriptional modification of pre-mRNA or nuclear mRNA involves the removal of introns (non-coding regions within genes) and stitching together of exons (coding regions of genes). This process is known as RNA splicing.
Following RNA splicing a chemical cap is added to the 5’ end of the molecule and a poly-A tail (string of A nucleotides) to the 3’ end. The 5’ cap enables efficient protein synthesis as it is part of the structure recognized by the small ribosomal subunit. The poly-A tail is also important for initiating translation. It also has a role in regulating the degradation of mRNA molecules in the cytoplasm.

132
Q

what is translation

A

It is the process by which RNA synthesizes proteins.

133
Q

write a detailed note on transcription of mRNA

A

mRNA exits the nucleus through nuclear pores and binds to ribosomes within the cytoplasm.
Translation of mRNA begins with the sequence AUG (start codon).
Transfer RNAs (tRNA) bring specific amino acids to the ribosome and these are added to the growing polypeptide chain by condensation polymerisation. New amino acids are added to the carboxyl (COOH) end of the polypeptide.
The tRNA drops away from the mRNA and acquires another specific amino acid from the pool in the cytoplasm. Each tRNA can only carry one type of amino acid.
Translation ends when the ribosome reaches a stop codon – the tRNA molecules corresponding to the stop codons UAG, UGA and UAA don’t carry a amino acid.
The mRNA is then released from the ribosome .

134
Q

what are interons

A

sequences in the DNA that are not used to make mRNA or to make proteins
they are not transcribed

135
Q

what are exons

A

sequences in the DNA that are expressed or used to make mRNA and ultimately are used to make proteins

136
Q

what is codon

A

Codon is the message on mRNA for specific aminoacid required for the protein, which is to b synthesized.
Each codon consists of 3 consecutive nitrogenous bases ,e.g for phenylalanine there are two codons i.e UUU and UUC .

137
Q

what is anticodon

A

Every codon has its specific anti codon . Anti codon has a sequence of 3 nitrogenous bases, which give the tRNA the specific property to recognize the site of codon present on mRNA.
Nitrogenous bases of anti codon are complementary to the nitrogenous bases of the codons.

138
Q

what is post translational modification

A

It is the modification of proteins after they have been synthesized .
Proteins may b modified by phosphorylation, glycosylation ,hydroxylation and addition of other groups .

139
Q

describe the four types of RNA

A 
Messenger RNA (mRNA)
Copied portion of coding DNA
Carries genetic information from the DNA out of the nucleus into the cytoplasm
Transfer RNA (tRNA)
Transports amino acids to the ribosome during protein synthesis
Ribosomal RNA (rRNA)
Structural component of ribosomes

snRNA (snRNA)
Involved in splicing of pre-mRNA message in the nucleus to remove introns

140
Q

describe the structure of tRNA

A

Also called soluble RNA

Largely in cytoplasm

Small and single stranded

At least 20 different tRNA molecules

Consists of 75 nucleotides
Their basis include
A , G , C , U , pseudouridine ,
uracil 5 ribofuranoside and thymine
in one loop

A clover leaf structure

H- bonds between bases

All tRNA molecules contains 4 arms r loops

Once a tRNA gene is transcribed, the RNA that is produced folds to form the shape of a three-leafed clover. This is a functional tRNA molecule.

This tRNA is charged with the amino acid lysine at the amino acid attachment site. The anticodon UUU will bind to the complementary AAA sequence in the mRNA

141
Q

what are the sources of calcium

A 
• Sources in the diet
• Milk
• Yogurt
• Cheese
• Dark green vegetables
• Fortified sources
• Cereals
• Bread
• Orange Juice
broccli
figs 
spinach 
sesame seeds 
cabbage
142
Q

what is daily requirement of calcium

A

Daily Recommended Intakes
• 9-18 years = 1300 mg
• 19-50 years = 1000 mg
• 51 years and older =1200 mg

143
Q

what are he functions of calcium

A 
Major component of bones and teeth
•A small amount of calcium circulates in the 
blood
•Essential for clotting of the blood
•Aids in the normal functioning of the 
nerves, muscles, and heart

• Ca salts in bone provide structural integrity of the skeleton.
• Ca is the most abundant mineral in the body.
• The amount of Ca is balance among intake, storage, and
excretion.
• This balance is controlled by transfer of Ca among 3
organs: intestine, bone, kidneys.
• Ca ions in extracellular and cellular fluids is essential to
normal function of a host of biochemical processes
• Neuoromuscular excitability and signal transduction
• Blood coagulation
• Hormonal secretion
• Enzymatic regulation
• Neuron excitation

144
Q

who is at risk of calcium deficiency

A
  • Children and youth
  • Post-menopausal women
  • Elderly
  • People with poor diets, lacking in dairy food
145
Q

how to reduce risk of osteoporosis

A

Calcium in the diet
• habitual exercise
• avoidance of smoking and alcohol intake
• avoid drinking carbonated soft drinks

146
Q

describe the formation and resorption of bone with respect to age and gender

A

The total bone mass of humans peaks at 25-35 years of age.
•Men have more bone mass than women.
•A gradual decline occurs in both genders with aging, but women
undergo an accelerated loss of bone due to increased resorption during
perimenopause.
•Bone resorption exceeds formation.

147
Q

what is the relationship of calcium with blood

A

Ca2+ normally ranges from 8.5-10 mg/dL in the plasma.
•The active free ionized Ca2+ is only about 48% 46% is bound to
protein in a non-diffusible state while 6% is complexed to salt.
•Only free, ionized Ca2+ is biologically active.

148
Q

what is the relationship of calcium with bone

A

• 99% of Ca is found in the bone. Most is found in hydroxyapatite
crystals. Very little Ca2+ can be released from the bone– though it is
the major reservoir of Ca2+ in the body.

149
Q

describe the intake of calcium

A

•About 1000 mg of Ca is ingested per day.
•About 200 mg of this is absorbed into the body.
•Absorption occurs in the small intestine, two mechanisms ve been
proposed for absorption of calcium by gut mucosa
1/ simple diffusion and
2/ active transport .

150
Q

describe the storage of calcium

A

•The primary site of storage is our bones (about
1000 grams).
• Some calcium is stored within cells (endoplasmic
reticulum and mitochondria).
•Bone is produced by osteoblast cells which
produce collagen, which is then mineralized by
calcium and phosphate (hydroxyapatite).
•Bone is remineralized (broken down) by
osteoclasts, which secrete acid, causing the release
of calcium and phosphate into the bloodstream.
•There is constant exchange of calcium between
bone and blood

151
Q

describe the excretion of calcium

A

The major site of Ca excretion in the body is the
kidneys.
•The rate of Ca loss and reabsorption at the kidney
can be regulated.
•Regulation of absorption, storage, and excretion of
Ca results in maintenance of calcium homeostasis

152
Q

describe the characteristics of plasma calcium and its subfractions

A

•Occurs in two forms.
Non- diffusible; This fraction cannot be dialyzed out bcoz it is in firm
combination with negatively charged plasma proteins specially albumin
and immunoglobulin.
Its level is 3.4 to 4.4mg/dl
Diffusible; It can b dialyzed out. It occurs in two subfractions.
• Ionized calcium
• Complexed calcium
•Ionized calcium 50%
• Protein-bound calcium 40%
• 90% bound to albumin
•Remainder bound to globulins
•Calcium complexed to serum constituents 10%
•Citrate and phosphate
•The normal level of plasma calcium is 9-10 mg / dl
•About 0.5 – 1 % of bone calcium is freely exchangeable
i.e in chemical equilibrium with calcium in ECF
•The exchange process is regulated primarily by the PTH, Active
Vitamin D & Calcitonin

153
Q

what are the factors affecting calcium level in plasma

A
  • Intestinal absorption
  • Excretion in urine
  • Amount of Ca absorbed from GIT
  • Parathyroid hormone
  • Inverse relation between plasma Ca and P levels
  • Plasma protein level
  • Renal excretion
  • calcitonin
154
Q

what are the actions of parathyroid hormone on bone

A

PTH acts to increase degradation of bone (release
of calcium).
- causes osteoblasts to release cytokines, which
stimulate osteoclast activity
- stimulates bone stem cells to develop into
osteoclasts
- net result: increased release of calcium from bone
- effects on bone are dependent upon presence of
vitamin D

155
Q

describe PTH general characteristics

A

PTH is synthesized and secreted by the parathyroid
gland which lie posterior to the thyroid glands.
•The blood supply to the parathyroid glands is from
the thyroid arteries.
•The Chief Cells in the parathyroid gland are the
principal site of PTH synthesis.
•It is THE MAJOR of Ca homeostasis in humans.

156
Q

how is PTH regulated

A

The dominant regulator of PTH is plasma Ca2+
.
• Secretion of PTH is inversely related to [Ca2+].
•Maximum secretion of PTH occurs at plasma Ca2+ below 3.5 mg/dL.
•At Ca2+ above 5.5 mg/dL, PTH secretion is maximally inhibited.

157
Q

describe the action of PTH

A

•The overall action of PTH is to increase plasma Ca2+ levels and
decrease plasma phosphate levels.
• PTH acts directly on the bones to stimulate Ca2+ resorption and kidney
to stimulate Ca2+ reabsorption in the distal tubule of the kidney and to
inhibit reabosorptioin of phosphate (thereby stimulating its excretion).
• PTH also acts indirectly on intestine by stimulating 1,25-(OH)2
-D
synthesis.

158
Q

what is the relationship between calcium and phosphate

A

Ca is tightly regulated with P in the body.
• P is an essential mineral necessary for ATP, cAMP 2nd messenger
systems, and other roles

159
Q

describe calcitonin with respect to calcium regulation

A

•Calcitonin acts to decrease plasma Ca2+ levels.
•While PTH and vitamin D act to increase plasma Ca2+
– only
calcitonin causes a decrease in plasma Ca2+
.
•Calcitonin is synthesized and secreted by the parafollicular cells of the
thyroid gland.
•They are distinct from thyroid follicular cells by their large size, pale
cytoplasm, and small secretory granules.
•Role of calcitonin in normal Ca2+ control is not understood—may be
more important in control of bone remodeling.
•Used clinically in treatment of hypercalcemia and in certain bone
diseases in which sustained reduction of osteoclastic resorption is
therapeutically advantageous.
•Chronic excess of calcitonin does not produce hypocalcemia and
removal of parafollicular cells does not cause hypercalcemia. PTH and
Vitamin D3 regulation dominate.
•May be more important in regulating bone remodeling than in Ca2+
homeostasis.
The major stimulus of calcitonin secretion is a rise in plasma Ca2+
levels
•Calcitonin is a physiological antagonist to PTH with regard to Ca2+
homeostasis
The target cell for calcitonin is the osteoclast.
•Calcitonin acts via increased cAMP concentrations to inhibit
osteoclast motility and cell shape and inactivates them.
•The major effect of calcitonin administration is a rapid fall in Ca2+
caused by inhibition of bone resorption.

160
Q

what are the actions of calcitonin

A

•The major action of calcitonin is on bone
metabolism.
•Calcitonin inhibits activity of osteoclasts, resulting
in decreased bone resorption (and decreased
plasma Ca levels).

161
Q

how does vitamin D facilitate calcium absorption

A

It facilitates intestinal absorption of calcium, as
well as stimulates absorption of phosphate and
magnesium ions.
In the absence of vitamin D, dietary calcium is not
absorbed at all efficiently.
Vitamin D stimulates the expression of a number of
proteins involved in transporting calcium from the
lumen of the intestine, across the epithelial cells
and into blood.
The vitamin D form, 1,25-dihydroxcholecalciferol
[1,25(OH)2D3],

•stimulates the synthesis of the epithelial calcium channels in the
plasma membrane calcium pumps , and
• induces the formation of the calbindins.

Once joined with ingested vitamin D, facilitate
increased serum calcium levels
Shows Expressed Calbindins and How this facilitate
transport of Calcium through the Membranes
•Calcium absorption is transport across the epithelial cell,
which is greatly enhanced by the carrier protein calbindin, the
synthesis of which is totally dependent on vitamin D

162
Q

describe excretion of calcium

A

Reabsorption occurs in proximal convoluted tubules, thick ascending
loop of Henle and in distal convoluted tubules amounting to 65%,
20%, and 10% respectively.
1… is coupled to Na+ reabsorption and takes place paracellularly.
2… is helped by protein paracellin & also paracellularly.
3… is occuring transcellularly. Ca enters the luminal surface of the
cell through apical Ca channels followed by its entry into cell interior
with calcium binding proteins Calbindin- D 28 K.

163
Q

what are the factor affecting absorption of calcium

A 
Ph of intestinal milieu
•Composition of the diet
 a) high protein diet
 b) fatty acids
 c) minerals
 d) sugars and organic acids
• State of the health of the individual and old age
•Hormonal
 a) PTH
 b) calcitonin
 c) glucocorticoids
164
Q

what is hypo and hyper calcium with their causes

A

Hypercalcemia
Serum calcium level exceeds 11.0 mg/dl

  • Hyperparathyroidism
  • Malignancy
  • Over dosage of vitamins
  • Drug induced hypercalcemia
  • Acute renal failure

Hypocalcemia
When serum calcium less than 8.5mg/dl

  • Hypoparathyroidism
  • Renal disease
  • Hypoalbuminaemia
  • Neonatal hypocalcemia
165
Q

what are macrominerals

A

required in amounts greater than 100mg/dl

166
Q

what are microminerals

A

required in amount less than 100mg/dl

167
Q

name the macrominerals

A 
calcium 
MG
K
S
Cl
P
Na
168
Q

what is the requirement of phosphorus

A

WBC contain 47mg P /dl as inorganic phosphate
RBC contain more P than plasma
Plasma contain more phosphorus than plasma
it plasma level is 3-4.5 mg/dl in adults
plasma level in children is 4-7 mg/dl (due to growth hormone)
dietary requirement is 1.5g

169
Q

sources of P are

A

cheese
milk
nuts
egg

170
Q

sources of iron are

A

Animal sources are the best and include liver, meat & egg yolk.
• Plant sources include spinach and green leafy vegetables.
• Milk is very low in iron.
• Cooking in iron utensils increases iron content of food

171
Q

what is the function of iron

A 
Helps in the formation of very important structures and compounds
of the body e.g
• Hemoglobin
• Myoglobin
• Cytochromes
• Catalase
172
Q

describe absorption of iron

A

Only 10% of ingested iron is absorbed.
• Absorption takes place at mid jejunum.
• Iron is first converted to ferrous form.
• It enters the intestinal mucosal cells by an energy dependant
transport mechanism.
• From the mucosal cells iron enters the plasma

173
Q

factors that increase iron absorption are

A

Increased erythropoieses e.g. At high altitude ,blood loss.
• Decreased iron stores e.g. In iron deficiency anemia and also after multiple
pregnancies.
• Increased iron absorption e.g. in case of taking vitamin C with iron.
• Inorganic form e.g. In iron supplements is absorbed very quickl

174
Q

factors that decrease iron absorption are

A

• Malabsorption as in steatorrhea, celiac disease.
• Diarrhoea because there is less time for iron to stay in intestine.
• Excess of phosphates and oxalates because these make insoluble
complexes with iron preventing its absorption.
• Antacid therapy.

175
Q

describe loss of iron from the body

A
  • Males ….0.5 -1 mg of iron /day
  • Females….35-70 ml of blood/day
  • Women lose iron during and after pregnancy
176
Q

describe iron deficiency

A

• Iron deficiency leads to Hypochromic- microcytic anaemia

177
Q

what are the causes of iron deficiency

A

Nutritional deficiency of iron
• Lack of absorption: Subtotal gastrectomy and hypochlorhydria
• Hookworm infection: One hookworm will cause the loss of
about 0.3 mL of blood per day.

178
Q

what is the required daily intake of iron

A

Adult - 20 mg of iron
•
• Children between 13–15 years need 20–30 mg/day.
• Pregnant women need 40 mg/da

179
Q

sources of copper and its content in body

A

The body contains about 100mg coThe body contains about 100mg
copper distributed in different organs.
• Liver is the richest source
• Copper distributed in different organs.

180
Q

describe absorption and secretion of cooper from the body

A

Only 5-10% of the ingested Cu is absorbed mainly in duodenum and
the remaining passes out in feces.
• Metallothionein is a transport protein that facilitates copper
absorption.
• Zinc and Molybedenum decrease copper uptake

181
Q

what are copper containing substances in the body

A 
Ceruloplasmin
• Erythrocuprin
• Cerebrocuperin
• Copper containing enzymes:
• Cytochrome oxidase
• Catalase
• Tyrosinase
• Monoamine oxidase
182
Q

what are the functions of copper

A

Copper is an essential constituent of several enzymes:
• Cytochrome oxidase
• Catalase
• Tyrosinase
• Monoamine oxidase
• Hemoglobin synthesis
• Lysyl oxidase (Cu containing enzyme):
• It is required for the conversion of certain lysine residues of collegen and
elastin to allysine which are necessary for cross-linking these structural
proteins.
• Ceruloplasmin serves as ferroxidase and is involved in the conversion of
iron from Fe⁺⁺ to Fe⁺⁺⁺ ,a form in which iron is transported in plasm
Copper is necessary for the synthesis of melanin and phospholipids.
• Development of bone and nervous system require Cu.
• Hemocyanin, a copper protein complex in invertebrates, functions
like hemoglobin for O₂ transpor

183
Q

what is RDA of copper

A

Adults __ 2-3 mg/day

• Infants and children__ 0.5-2 mg/day

184
Q

what are the clinical disorder associated with copper

A
  • Wilson’s disease

* Menke’s disease

185
Q

describe wilsons disease

A

Hepatolenticular degeneration)
• In liver, lenticular nucleus of brain and the descements membrane of
the cornea.
• Diagnostic feature is the presence of Kaeyser Fleischer ring in
the cornea

186
Q

describe menke’s disease

A

Genetic disorder of poor Cu++ absorption.
• Failure to grow
• Mental deterioration
• Degenerative changes in the metaphysis
and in the elastin of aorta

187
Q

what are sources of zinc

A

shellfish
poultry
meat

mushrooms
legumes
whole grains

188
Q

what is the RDA of zinc

A

• Men: 11 mg/day
• Women: 8 mg/day
• The total content of zinc in an adult body is about 2 g.
• Erythrocytes contain higher content of Zn (1.5 mg/dl) which is
found in association with the enzyme carbonic anhydrase

189
Q

what are the functions of zinc

A

It is an essential component of several enzymes e.g
Carbonic anhydrase, Alkaline phosphatase etc
• It may be regarded as an antioxidant since the enzyme superoxide dismutase
protects the body against free radical damage.
• The storage and secretion of insulin from β-cells of pancreas require Zn.
• It is required for wound healing
• Gusten, a zinc containing protein of the saliva, is important for taste

190
Q

describe zinc deficiency

A

• Zinc deficiency is associated with growth retardation, poor wound
healing, anaemia, loss of appetite, loss of taste sensation, impaired
spermatogenesis .
• Deficiency of Zn may result in depression, dementia and other
psychiatric disorders.
• Acrodermatitis Enteropathica:
Rare inherited metabolic disease of zinc deficiency caused by defect
in Zn absorption from intestine.

191
Q

describe zinc toxicity

A

Is often observed in welders due to inhalation of zinc oxide fumes.
• Manifested by nausea , gastric ulcer , pancreatitis and excessive
salivation

192
Q

what are the sources of sulfur

A 
meat 
fish 
eggs 
cheese
tea
cocoa
dried apricots
193
Q

what are the functions of sulfur

A

Sulfur containing amino acids are important constituents of body
proteins.
• The disulfide bridges keep polypeptide units together, e.g. insulin,
immunoglobulins.
• Chondroitin sulfates are seen in cartilage and bone.
• Keratin is rich in sulfur, and is present in hair and nail
• Co-enzymes derived from thiamine, biotin, pantothenic acid and
lipoic acid also contain sulfur.
• Sulfates are also important in detoxification mechanisms, e.g.
production of indoxyl sulfate

194
Q

describe content, absorption, excretion of iodine

A

• The total body contains about 20 mg iodine, most of it (80%) being
present in the thyroid gland.
• It is mainly absorbed from the small intestine.
• Iodine absorption also occurs through skin and lungs.
• Its excretion mostly occurs through kidney & also through saliva, bile,
skin and milk (in lactating women)

195
Q

what is the RDA of iodine

A

ADULTS ➔ 100-150 µg/day

• PREGNANT WOMEN ➔ 200 µg/day

195
Q

what are the sources of iodine

A 
Sea foods
• Drinking water
• Vegetables
• Fruits
• Iodized salt
196
Q

describe deficiency of iodine

A
  • Simple Goitre:
  • Thyroxin function is low
  • Weight gain
  • Thick skin
  • Sleepiness
  • Coarse voice
  • Constipation.
197
Q

describe toxic goiter

A 
Hyper functioning of the thyroid gland
• Weight loss
• Anxiety
• Lack of sleep,
• Fine tremors of fingers
• Bulging eyes (Exophthalmos)
• Diarrhoea
198
Q

describe cretinism

A

Deficiency of Iodine in newborns
may lead to hypothyroidism
which may cause problems
with brain growth.

199
Q

what is RDA of selenium

A

• Upper level for adults: 400 g/day

200
Q

what are the sources of selenium

A

Seafood, meat
• Whole grains
• Vegetables

201
Q

what are the functions of selenium

A

Acts as co-factor of glutathione (an antioxidant tripeptide).
• Defends against oxidation (antioxidant role).
• Regulates thyroid hormone

202
Q

describe role of selenium as antioxidant

A

Helps in lowering oxidative stress
in the body, which reduces
inflammation and enhances
immunity

203
Q

describe deficiency of selenium

A

• Predisposition to heart disease characterized by cardiac tissue
becoming fibrous.

204
Q

describe toxicity of selenium

A

Loss and brittleness of hair and nails
• Skin rash, fatigue, irritability, and nervous system disorders
• Garlic breath odor

205
Q

what is the RDA of fluoride

A

Men: 3.8 mg/day.
• Women: 3.1 mg/day.
• Upper level for adults: 10 mg/day

206
Q

what are chief functions of fluoride

A
  • Involved in the formation of bones and teeth.

* Helps to make teeth resistant to decay

207
Q

sources of flouride

A
  • Drinking water (if fluoride containing or fluoridated).

* Tea, seafoo

208
Q

describe deficiency of fluoride

A

• Susceptibility to tooth decay.

209
Q

what are symptoms of fluoride toxicity

A

Fluorosis (pitting and discoloration of teeth).

210
Q

what is RDA manganese

A
  • Men: 2.3 mg/day
  • Women: 1.8 mg/day
  • Upper level for adults: 11 mg/day
211
Q

what are the sources of manganese

A

Nuts
• Whole grains
• Leafy vegetables

212
Q

what are the functions of manganese

A

: cofactor for many enzymes that metabolize carbohydates,

lipids and amino acids

213
Q

what is the RDA of chromium

A

Men: 35 g/day.

• Women: 25 g/day.

214
Q

what is the function of chromium

A

• Enhances insulin action.

215
Q

what are sources of chromium

A

Meats (especially liver).

• Whole grains, brewer’s yeast

216
Q

what are symptoms of chromium deficiency

A

Diabetes-like condition

217
Q

what is RDA of molybdenum

A

for adults: 45 g/day.

• Upper level for adults: 2 mg/day.

218
Q

what are sources of molybdenum

A
  • Legumes, cereals.
  • Organ meats.
  • Reproductive effects in animals
219
Q

what is the function of molybdenum

A

• Cofactor for several enzymes e.g. xanthine oxidase

CBA- 1 (8 decks)

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