Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Y1B1 (PAECH & PBBG) πŸ“• > Biochemistry πŸ§ͺ > Flashcards

Biochemistry πŸ§ͺ Flashcards

1
Q

What are cabohydrates?

A

-they are organic compounds that are formed mainly of CHO but not always where is the ratio of hydrogen to oxygen is 2:1 like water they are called carbohydrates.

  • they are defined as polyhydroxy aldehydes and polyhydroxy ketones or any other compounds yielding them on Hydrolsis.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What is the function of carbohydrates?

A

they are the main source of energy and they enter in the structure of sugar-phosphate backbone,cell membrane,glycolipids and glycoproteins. they play a role in cell recognition as well

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

What are monosaccharides classified according to?

A

They are classified according to the number of carbon atoms and active carbonyl group whether it is aldehyde or Ketone.

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

Triose

A

Glycerldehyde

Dihydroxy acetone

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

Tetrose

A

Erythrose

Erthyroluse

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

Pentose

A

Arabinose
Ribose
Xylose

Xylulose
Ribulose

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Hexose

A

Glucose
Galactose
Mannose

Fructose

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

Heptose

A

β€”β€”-

Sedoheptulose

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

What is the importance of glucose?

A

-It is a major source of energy for tissues and cells.

-some tissues and cells like brain and erthrocytes depends mainly on glucose as it cant oxidize on the any other alternatives for fuel.

-therefore the body keeps a fairly constant amount in the blood ranging between 70 to 110 mg/dl.

-all the ingested sugar is absorbed in the form of glucose.

-It is a changed into other forms like galactose,ribose,fructose and glygogen in other organs like the liver.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Galactose

A

-It is formed in mammary glands.

  • It helps in the formation of lactose.

-It is a constituent Of glycolipids and glycoproteins.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Mannose

A

It is a constituent of glycoproteins and Amino sugar acids.

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

Fructose (levulose) (fruit sugar)

A

-It is found in the seminal fluid as to provide energy for the sperms.

-It is also a constituent in the formation of Inulin which is a polysaccharides and sucrose which is a disaccharide.

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

Ribose

A

-It enters in the structure of sugar-phosphate backbone.

-It enters in the formation of co enzymes like NAD.

-Deoxy ribose enters in the formtion of DNA.

-Ribose enters in the formation of RNA - ATP -NAD.

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

What are sugar derivatives?

A

-Sugar acids
-Deoxy sugars
-Amino sugar
-Amino sugar acids
-Glycosides

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

What are sugar acids?

A

-They are the yield of the oxidation of carbon atoms to carboxylic groups.

Firstβ€”β€”> aldonic acids
Lastβ€”β€”> uronic acids
Bothβ€”β€”> aldaric acids β€œglucaric is sacharic acid”

And ascorbic acid β€œvitamen C” which is six carbon sugar acid and it is soluble in water and optically active and must be supplied in diet.

By glucose oxidase enzymes and this technique is used in test stripes to test the amount of sugar in blood and urine

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

Give examples for amino sugars

A

-glucosamine
-Galactoseamine

β€œAnd they are found in glycoseamineglycans (GAGS)
And glycoproteins”

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

What are amino sugar acids?

A

-They are the yield of condensation reaction between acids and amino sugars like neuraminic acid which is found in neural tissues and is formed duet l the reaction between mannosamine and pyruvic acid.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

What are glycosides?

A

They are compounds that are connected by glycosidic bonds and there are two types of glycosidic bonds O and N.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

What are O-Glycosides ?

A

-they are compounds that contain O-glycosidic bond between and it arises by the attachment of the hydroxyl group on the sugar with the hydroxyl group on the other compound whether it is a CHO or not by removal of water.

From the examples:glycoproteins (Hydroxy amino acids) ,Glycolipids ,Disaccharides ,Poly saccharides and oligosaccharides, Cardiac glycosides β€œgalactose + steriod β€œ(digitalis used for treating heart failure).

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

What are N-Glycosides?

A

-They are compounds that contain N-Glycosidic bonds between them that arise from the attachment of the hydroxyl group of the sugar with the amino group of the other compound.

For example:- DNA and RNA nucleotides.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

Symptoms of diabetes

A

-Polyuria
-Polyphagia
-Polydipsia

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

How are glycosides named?

A

-They are named according to the sugars they contain.

E.g: Glucosides, galactosides

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

what do disaccharides consist of?

A

two monosaccharides

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

what are non-reducing diasaccharides?

A

Non-reducing disaccharides: two aldehyde/or ketone groups are involved in the linkage (anomeric C not free) e.g. sucrose (reduction happens to fehling solution)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

what are reducing disaccharides?

A

if one of aldehyde/or ketone groups is free (free anomeric C) e.g. Lactose and Maltose.
Classification:

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

what are the most abundant disaccharides? β€œMLS”

A

sucrose, lactose and maltose.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

what are other names of maltose?

A

(malt sugar, maltose syrup)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

Maltose(malt sugar, maltose syrup)

A

2 alpha Dextro glucose - alpha 1 4 glycosidic bond
(reducing)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
29
Q

isomaltose

A

It is formed of two Ξ±-glucose but linked together by Ξ± 1-6 glycosidic bonds. It is a reducing sugar.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
30
Q

cellobiose

A

It is formed of two units Ξ²-glucose linked together by a Ξ²1-4 glycosidic bond.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
31
Q

sucrose(cane sugar, beet sugar, table sugar)

A

Formed of Ξ±-glucose and Ξ²-fructose linked by an Ξ±-1- Ξ²-2 glycosidic bond (involving the anomeric Cs). (non-reducing)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
32
Q

lactose(milk sugar)

A

It is formed from Ξ²-galactose and Ξ²-glucose via a Ξ² (1-4) link with free anomeric C. It is a reducing sugar.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
33
Q

starch hydrolysis

A

starch is hydrolyzed by pancreatic and salivary amylase giving maltose which is hydrolyzed by maltase giving two glucose units.

starch is also be hydrolyzed by acids giving dextrins which are hydrolyzed by alpha dextrinase giving smaller units.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
34
Q

dextran hydrolysis

A

dextran is hydrolyzed into isomaltose

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
35
Q

cellulose hydrolysis

A

is ts hydrolyzed by acids into cellobiose.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
36
Q

sucrose hydrolysis

A

it is hydrolyzed by sucrase into alpha glucose and beta fructose.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
37
Q

lactose hydrolysis

A

it is hydrolyzed by intestinal lactase into beta glucose and beta galactose

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
38
Q

what are the characteristics of lactose sugar?

A

β€’ It is the principal carbohydrate in milk and is of critical nutritional importance to mammals in the early stages of their lives.

β€’ It may appear in the urine in late pregnancy and during lactation

β€’ Low levels of lactase enzyme lead to undigested lactose that undergoes bacterial fermentation in the colon with the generation of large amounts of CO2, H2, and irritating organic acids.

β€’ These products cause painful digestive upsets known as lactose intolerance.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
39
Q

what are oligosaccharides?

A

β€’ Oligosaccharides consist of 3-10 monosaccharide units joined together by glycoside bonds. E.g. Maltotriose.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
40
Q

what is the existence and significance of oligosaccharides?

A

β€’ Oligosaccharides are important as constituents of the glycolipids and glycoproteins of the cell membrane.

β€’ Many secreted proteins, such as antibodies and coagulation factors also contain oligosaccharide units.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
41
Q

what are polysaccharides?

A

β€’ Polysaccharides, also called glycans, consist of more than 10 monosaccharide units and/or their derivatives joined together by glycosidic linkage.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
42
Q

what are polysaccharides classified according to?

A

according to structure and function

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
43
Q

how are polysaccharides classified structurally?

A
  1. Homopolysaccharides (homoglycans): contain only one type of monosaccharide. E.g. starch, glycogen, dextran, dextrin, cellulose, inulin.
  2. Heteropolysaccharides (heteroglycans): contain more than one type of monosaccharides. E.g. glycosaminoglycans (GAGs, mucopolysaccharides), agar.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
44
Q

How are polysaccharides classified functionally?

A

Polysaccharides are classified according to their function into storage and structural polysaccharides.

β€’ Storage polysaccharides: starch, glycogen, dextran, and inulin.

β€’ Structural polysaccharides: cellulose and agar.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
45
Q

starch

A

It is a glucosan (a-D glucose units) consists of 2 layers:
β–Ί An inner linear nonbranching layer called amylose.
β–Ί An outer highly branched layer is called amylopectin. The branch points occur about once every thirty linkages.

-Main storage of polysaccharides in plants.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
46
Q

Glycogen(animal starch)

A

-Glucosan

β–ΊIt is a highly branched molecule (branches every 10 glucose units; more branched than amylopectin). It yields a red-violet color with iodine.

-Main storage of polysaccharides in humans and animals

-It is present mainly in the liver 10% and in the skeletal muscles 1-2% and breaks down to glucose when fasting which helps in maintaining glucose levels in the blood.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
47
Q

dextran

A

-It is formed of Ξ±-glucose units (glucosan).

-It is a storage polysaccharide in yeasts and
bacteria

-Bacterial dextrans are used in laboratories as the support medium for chromatography of macromolecules and as replacement therapy in blood loss.

-Dental plaque is due to dextran synthesized from sucrose by oral bacteria.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
48
Q

cellulose

A

-It is formed of Ξ²-D-glucose units.

-It is the most abundant natural polymer found in the world. It is the structural component of the cell walls of nearly all plants.

-Cellulose is extremely resistant to hydrolysis whether by acid or by the digestive tract amylases. So, it can stimulate peristaltic movement and prevent constipation.

-The bacteria that live in the gut of ruminant animals secrete cellulase enzyme (Ξ²- glucosidase) which is effective in the hydrolysis of cellulose.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
49
Q

inulin

A

-It is formed of fructose (fructosan).

-Hydrolyzed by the enzyme inulinase in plants. It has no dietary importance in human beings as inulinase is absent in human

-It is used in the inulin clearance test to determine the rate of glomerular filtration. It can be used as a diet for diabetics.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
50
Q

alpha dextrin

A

Starch is partially hydrolyzed by acids or enzymes into dextrins and it is hydrolyzed by alpha dextrinase

-It is used as mucilage.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
51
Q

what are the examples of heteropolysaccharides?

A

agar

GAGS (glycosaminoglycans - mucopolysaccharides)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
52
Q

Agar

A

β€’ A polysaccharide isolated from marine red algae.

β€’ Composed of agarose and agaropectin

β€’ Agarose gel is used in gel chromatography and gel electrophoresis.

β€’ Nutrient agar is used in the preparation of culture media in microbiology

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
53
Q

GAGS

A

β€’ GAGs are long linear unbranched chains composed of a repeating disaccharide unit (acidic sugar-amino sugar) .

β€’ The amino sugar: (D-glucosamine or D-galactosamine) and the amino group is usually acetylated (sometimes sulphated).

β€’ The acid sugar: either glucuronic or L-iduronic

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
54
Q

chondroitin sulfate

A

-glucuronic acid
-N-galactosamine (acetylated)
-sulphated
-cartilage, tendons, ligaments, bone, heart valves, aorta.
-Most abundant GAG
-protective and supportive.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
55
Q

keratan sulphate

A

-no uronic acid
-N-glucosamine (acetylated) and galactose -6- sulfate
-Sulfated
-cornea, bone,cartilage
-aggregated with chondroitin sulfate
-protective and supportive

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
56
Q

dermatan sulphate

A

-L-iduronic acid
-N-galactosamine (acetylated)
-Sulfated
-skin, blood vessels, heart valves
-protective and supportive.
Usually replaces hyaluronic acid in aged skin and blood vessels

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
57
Q

heparin

A

-glucuronic and iduronic acid
-Glucosamine (non-acetylated)
-More Sulfated
-Intracellular granules of mast cells lining the arteries of the lungs, liver and skin
-Anticoagulant

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
58
Q

heparan sulphate

A

-glucuronic or iduronic acid
-Glucosamine (acetylated)
-Less Sulfated
-Extracellular GAG, basement membranes of cell surface
-components of the cell surface.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
59
Q

hyaluronic acid

A

-glucuronic acid
-Glucosamine (acetylated)
-Non sulfated
-synovial fluid of joints, vitreous humor
of eye, skin ECM of loose connective tissue
-shock absorbing, lubricant.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
60
Q

what are proteoglycans?

A

β€’ All of the GAGs except hyaluronic acid and heparin are found covalently attached to a protein, forming proteoglycan monomers.

β€’A proteoglycan monomer found in cartilage consists of a core protein to which the linear carbohydrate chains are covalently attached.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
61
Q

What are amino acids?

A

-The are the structural units of proteins, and they are obtained from proteins by acid,alkali or enzymatic hydrolysis.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
62
Q

What is the general structure of amino acids?

A

All amino acids except proline and hydroxyproline consist of:-

Carboxyl group COOH
Amino group NH2
Side chain (Characteristic to each amino acid)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
63
Q

What are amino acids classified according to?

A

-The acid they are derived from.
-The number of carboxyl and amino groups.
-Their nutritional importance.
-Their metabolism.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
64
Q

How are amino acids condensed?

A

By the reaction between COOH group and NH2 associated with removal of water forming petide bonds.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
65
Q

What are pure glucogenic amino acids?

A

-They are amino acids that can be converted into carbohydrates.

And they are All except leucine,lysine,Isoleucine,Tyrosine,Tryptophan and Phenyl alanine.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
66
Q

What are pure ketogenic amino acids?

A

-They are amino acids that can be converted into ketone bodies like Leucine.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
67
Q

What are mixed amino acids?

A

-They are amino acids that can be converted to both carbohydrates and ketone bodies like Isoleucine,Lysine,Phenylalanine,Tyrosine and tryptophan

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
68
Q

What are essential and non essential amino acids?

A

-Essential amino acids: They are amino acids that are not synthesized in the body and must be taken in diet.

-Non-Essential: they are amino acids that are synthesized in the body and there is no need to be taken in diet

β€œVILAr HM= Ten THousand Pounds”

Valine
Isoleucine
Lysine
Leucine
Arginine
Histidine
Methionine
Tryptophan
Threonine
Phenylalanine

And anything else is non-essential

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
69
Q

What are basic amino acids?

A

They are amino acids in which the number of amino groups is more than the number of carboxylic groups like

Ar - H - Ly

Arginine
Histidine
Lysine

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
70
Q

What are acidic amino acids?

A

-They are amino acids in which the number of carboxylic groups is more than the number of amino groups.

Glutamic acid
Aspartic acid

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
71
Q

What are neutral amino acids?

A

-They are amino acids in which the number of carboxylic groups equal the number of amino groups.

Aliphatic (Gavil): glycine-Alanine-Valine-Isoleucine-Leucine

Containing hydroxyl(TTSH): Tyrosine-Threonine-Serine

Containing sulphur(CCM): Cystine-Cysteine-Methionine

Aromatic amino acids(TTPh):Tyrosine-Tryptophan-phenylalanine

Heterocyclic amino acids: proline-hydroxyproline

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
72
Q

What are amino acids derived from acetic acid?

A

Glycine

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
73
Q

What are amino acids derived from propanoic acid?

A

Alanine
Serine
Cystine
Cysteine
Phenylalanine
Tyrosine
Tryptophan
Histidine

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
74
Q

What are amino acids derived from butyric acid?

A

Threonine
Methionine

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
75
Q

What are amino acids derived from Valeric acid?

A

Arginine

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
76
Q

What are amino acids derived from isovaleric acid?

A

Isoleucine
Valine

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
77
Q

What are amino acids derived from caproic acid?

A

Lysine

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
78
Q

What are amino acids derived from isocaproic acid?

A

Leucine

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
79
Q

What are amino acids derived from dicarboxylic acids?

A

Glutamic acid
Aspartic acid

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
80
Q

What are Imino acids?

A

Proline
Hydroxy proline

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
81
Q

What are branched chain amino acids?

A

Valine, isoleucine and leucine

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
82
Q

Describe chemical reactions of amino acids

A
  • Reaction due to both NH2 and COOH group:

Amino acids condenese with each other by COOH group at one amino acid with of other amino acid to form peptide bond.

If 3 amino acids condense together they form Tripeptide and so on,,,,,

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
83
Q

What are proteins?

A

Organic complex nitrogenous compounds of high molecular weight formed of C, H, O, N [N= 16%].

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
84
Q

What is the biological importance of proteins?

A

1) Antibodies (immunoglobulin) are proteins
2) Buffer system of blood (plasma proteins).
3) Carry hormones and minerals in blood (plasma proteins), Carry oxygen (Hemoglobin).
4) Structure of cell membrane.
5) Support bone, skin, nails, and hair.
6) Hormones as insulin.
7) Enzymes are proteins.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
85
Q

What are proteins classified according to?

A

1) According to shape
2) According to Nutritional value
3) According to their chemical structure

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
86
Q

What are the types of proteins according to shape?

A

Fibrous and globular

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
87
Q

Fibrous proteins

A

-Long, narrow fibers
-More than 10
-Insoluble
-More stable
-Actin, Myosin, collagen

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
88
Q

Globular proteins

A

-Rounded (spherical)
-Axial ratio Less than 10
-Soluble
-Less stable
-Albumin, hemoglobin, insulin

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
89
Q

What are proteins classified to according to nutritional value?

A

-nutritionally rich proteinsβ€”>contain all the essential amino acids.
-incomplete proteinsβ€”->Lack one essential amino acid.
-poor proteinsβ€”->Lack many essential amino acids.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
90
Q

Give examples of proteins classified according to their nutritional value respectively.

A

1-caseinogen(protein of milk)

2-proteins of pulses lack methionine, proteins of cereals lack lysine.

3- zein of maize protein lacks lysine and tryptophan.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
91
Q

What are proteins classified into according to their chemical structures?

A

-simple, compound, and derived.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
92
Q

What are simple proteins?

A

On hydrolysis, they produce only amino acids.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
93
Q

Give examples for globular and fibrous simple proteins.

A

The first six are globular.

1-albumin
2-globulin
3-Glutillin
4-Prolamin
5-Protamin
6-histones
7-albuminoids(scleroproteins)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
94
Q

Albumin

A

Coagulated by heat

-present in egg (egg albumin),blood (plasma albumin)and milk (lactoalbumin)

95
Q

Globulin

A

-Coagulated by heat

-present in egg (egg globulin), blood (plasma globulin), milk (lactoglobulin)

96
Q

Glutellin

A

as glutenin of wheat.

97
Q

Prolamin

A

-as Zein of corn and maize.

  • deficient in tryptophan amino acid β†’
98
Q

Protamin

A

-Rich in basic amino acids.

-found in combination with nucleus acid of Salomon.

99
Q

Histones.

A

-rich in basic amino acids.

-found in combination with nucleic acids in human

-found in globin of HB.

100
Q

Albumins

A

they are fibrous proteins.

Insoluble in water ,dilute acids and alkali and all neutral solvents.

Not digested by proteolytic enzymes.

Found in animal tissues and having supportive and protective functions.

Ex:
A. Keratin:present in hair, nail

B. Elastin: present in joints, wall of lung alveoli and ligaments

C. CollageN:present in skin, bone, cartilage, and connective tissues

101
Q

What are conjugated proteins?

A

they are formed of protein and non-protein part.

102
Q

Give examples for conjugated proteins

A

-Glycoproteins
-lipoproteins
Phosphoproteins
-metalloproteins
-Chromoproteins(hemo and flavo)
-Nucleoprotein

103
Q

What are glyco proteins(much-proteins)?

A

proteins are conjugated with carbohydrates

οƒœ Ex: Hormones (FSH, LH), Enzymes.
οƒœ Mucin of GIT.
οƒœ Antibodies, blood group Antigen. .

104
Q

What are lipoproteins?

A

proteins are conjugated with lipids.

Ex: Chylomicrons VLDL
LDL, HDL.

105
Q

What are phosphoproteins?

A

Proteins are conjugated with phosphoric acid.

Ex: Caseinogen (main protein of milk).

106
Q

What are metalloproteins?

A

Proteins are conjugated with metals.

Ex: Ceruloplasmin (protein + Cu).

οƒœ Insulin (protein + Zinc).

οƒœ Ferritin (Fe)

107
Q

What are chromatoproteins?

A

-Hemoproteins
-Flavoproteins

108
Q

What is hemoproteins?

A

protein + heme (red pigment)

as Hemoglobin and cytochromes (components of electron transport chain)

109
Q

What are favoproteins?

A

proteins + FAD (yellow color).

110
Q

What are nucleoproteins?

A

Proteins are conjugated with nucleic acids.

Ex:
Histone + DNA in chromosome.

protein + RNA in Ribosome.

111
Q

What are derived proteins

A

they are denaturated or hydrolytic products of simple or conjugated proteins .

112
Q

What are the types of derived proteins ?

A

Primary and secondary

113
Q

What are primary derived proteins?

A

result from of proteins from its native state without hydrolysis of peptide bond

Ex:-meta which are produced by hydrolysis with a cid or alkali

Coagulated which result from hydrolysis with heat

114
Q

What are secondary derived proteins?

A

They are hydrolysis products of proteins.

Proteomes: Products of partial hydrolysis of proteins

Peptones: Products of proteoses hydrolysis.

Peptides: Products of peptones hydrolysis.

115
Q

What are the orders of protein structure?

A

There are four orders of protein structures:
1) Primary structure of Proteins
2) Secondary structure of Proteins
3) Tertiary structure of Proteins
4) Quaternary structure of Proteins

116
Q

Primary structure of the protein

A

οƒœ Referred to the number, type, and sequence of amino acids in the polypeptide chain.

οƒœ Any change in one of the amino acids in the polypeptide chain produces a physiological defect.

οƒœ The main bond in this structure is the peptide bond.

οƒœ The free -NH2 group of the 1st amino acid is called as N-terminal end and the free - COOH end of the last amino acid is called as C-terminal end.

117
Q

What is the secondary structure of proteins?

A

The polypeptide chain will be folded to give a specific shape form which may be:
a) Ξ±-Helix
b) Ξ²-pleated Sheets
c) Supersecondary structures(motifs)

118
Q

Ξ±-Helix

A

οƒœ The polypeptide chain is twisted to a right-handed coiled helix.
οƒœ each turn contains 3.6 amino acids, which is a common secondary structure in globular proteins.
οƒœ The formation of the Ξ±-helix is spontaneous and is stabilized by Hydrogen bonds between carbonyl Oxygen of peptide bond and hydrogen of NH of the next 4th peptide bonds in the chain.

119
Q

Ξ²-pleated Sheets

A

οƒœ Formed when hydrogen bonds are formed between two or more adjacent polypeptide chains.
οƒœ The hydrogen bonds are inter-chain.
οƒœ It is pleated due to the angles of bonds.

120
Q

Super secondary structures (motifs)

A

οƒœ Combinations of Ξ±-helix and Ξ²-sheets to form a specific shape.
οƒœ It gives protein a specific structure feature to enable a particular function.

οƒœ EX: Helix-turn-helix (HTH)
οƒœ Two Ξ± helices are joined by a short strand of amino acids.
οƒœ Is a major structural motif capable of binding DNA.

121
Q

The tertiary structure of proteins

A

οƒœ Secondary structures are arranged to form a final functional 3D structure called domain.
οƒœ It occurs due to interaction between side chains (R) of the amino acids.
domain.
οƒœ There are forces controlling tertiary protein structure.

122
Q

What are the forces controlling the tertiary structure of proteins?

A

Hydrogen bond: Between polar side chains of amino acids.

Hydrophobic forces: Between the non-polar (R) groups of the amino acids

Electrostatic forces(ionic bonds, salt bridges): Between oppositely charged (R) groups of amino acids

Disulfide bonds: Between sulfur amino acids (cysteine)

123
Q

Quaternary structure of the protein

A

οƒœ Special arrangement of more than one polypeptide chain (subunits = monomers).
οƒœ The bonds: Non-covalent (hydrogen or ionic bonds)
οƒœ This high level of organization is essential for the activity of some proteins like hemoglobin, enzymes.

124
Q

What are the examples of oligomeric proteins (quaternary structure of proteins)?

A

-Creatine kinase (CK) enzyme is a dimer.

  • Haemoglobin and lactate dehydrogenase (LDH) enzymes are tetramers.
125
Q

What is the definition of protein folding?

A

It is a physical and dynamic process by which a string of amino acids interacts with itself to form a stable three-dimensional (3D) structure during the production of the protein within the cell.

126
Q

What is the importance of protein folding?

A

1) Production of protein structures that can perform specific functions in the cell.
2) Prevent non-specific interaction of the protein with other proteins (prevent protein aggregation).

127
Q

What is the mechanism of protein folding?

A

Occurs spontaneously, but there is a class of specialized proteins; chaperones, whose function is to assist in this process.

128
Q

What are the causes of protein misfolding?

A

1-Spontaneous

2-Mutation in a particular gene, which then produces an altered protein.

3-Some proteins after abnormal proteolytic cleavage can take on a
unique conformational state that leads to the formation of long fibrillar protein assemblies consisting of Ξ² pleated sheets (its accumulation β†’Amyloidosis).

129
Q

What are the effects of protein misfolding?

A

There is a deposition of misfolded proteins as insoluble aggregates within the cell.

130
Q

What are examples of diseases due to protein misfolding?

A

Alzheimer’s disease: deposits of amyloid-beta and tau.

Type II diabetes: deposits of amylin.

Parkinson’s disease: deposits of alpha-synuclein.

131
Q

What is protein denaturation? What is the definition of protein denaturation?

A

Disruption of the secondary, tertiary, and wherever applicable quaternary organization of a protein molecule due to cleavage of non-covalent bonds.

N.B: The primary structure of protein molecule is not affected, i.e. peptide bond is not affected

132
Q

What are the agents for protein denaturation?

A

Physical:
1) Heat
2) UV light
3) Ultrasound
4) Hight pressure
5) Violent shaking

Chemical:
1) Strong acids
2) Strong alkalies
3) Organic solvents
4) Heavy metal salts

133
Q

What are the applications of denaturation?

A

οƒœ Medical supplies and instruments are sterilized by heating to denature proteins in bacteria and thus destroy the bacteria.

οƒœ The acid gastric juices cause the denaturation of protein.

οƒœ 70% alcohol solution is used as a disinfectant on the skin. This concentration of alcohol is able to penetrate the bacterial cell wall and denature the proteins and enzymes inside of the cell.

134
Q

What are the results of denaturation?

A
  • Chemical:
     Unfolding of the protein molecule.
     Destruction of some subsidiary hydrogen bonds.
     Exposure of some groups as (SH) of cysteine.
  • Biological:
     Loss of activity if it is a hormone or enzyme.
     Easily digested.
135
Q

What are lipids?

A

❖ Lipids are compounds that are relatively insoluble in water, but freely soluble in non-polar organic solvents like benzene, ether, and acetone, etc.

136
Q

What is the biological importance of lipids?

A

1) Storage form of energy (triglycerides).

2) Structural components of membranes (phospholipids and cholesterol).

3) Metabolic regulators (e.g. steroid hormones).

4) Help in the absorption of fat-soluble vitamins (A, D, E, and K).

5) Protect internal organs by providing a cushioning effect (pads of fat).

6) Provide insulation against changes in external temperature (subcutaneous fat).

7) Act as electric insulators in neurons.

137
Q

What are lipids classified into?

A

1) Simple lipids:
❖ They are formed of fatty acids and alcohol.
❖ They are further classified according to the type of alcohol present into:
 Fats and oils.  Waxes.

2) Compound lipids:
❖ They are formed of simple lipids and another non-lipid part.

3) Derived lipids:
❖ They are substances derived from simple lipids and compound lipids by hydrolysis.
❖ They also include substances related to lipids and associating lipids in nature.

138
Q

What is glycerol?

A

It is polyhydric alcohol containing 3 OH groups.

139
Q

What is the importance of glycerol?

A

It is used in pharmaceutical (e.g. glycerin suppositories) and cosmetic preparations.

It is used as a vasodilator agent in coronary heart disease in form of nitro-glycerine.

140
Q

fatty acids

A

❖ Fatty acids are usually monocarboxylic straight aliphatic chains with a methyl group at one end (called the Ο‰-carbon) and a carboxyl group at the other end.
❖ It is the most common component of lipids in the body.
❖ They are generally found in ester linkage in different classes of lipids

141
Q

How are fatty acids numbered?

A

1) C-system numbering starts from the carboxyl-terminal:
2) Ο‰-system numbering starts from the methyl end:

142
Q

How are fatty acids classified depending on the total number of carbon atoms in the chain?

A

Even chain:
οƒœ They have carbon atoms 2, 4, 6, and similar series.
οƒœ Most of the naturally-occurring lipids contain even chain fatty acids.

Odd chain: οƒœ They have carbon atoms 3, 5, 7, etc.

143
Q

How are fatty acids classified?

A

Acc. To total number of carbon atoms in the chain

Acc. To the length of the hydrocarbon chain

Acc. To the nature of the hydrocarbon chain

144
Q

How are fatty acids classified depending on the length of the chain?

A

-Short with 2 to 6 carbon atoms.
-medium with 8 to 14 carbon atoms.
-long with 16 to 22 carbon atoms.
-very long with more than22 carbon atoms.

145
Q

How are fatty acids classified according to the nature of the hydrocarbon chain?

A

❖ Saturated fatty acids.

❖ Unsaturated fatty acids:
May be sub-classified into:

Mono-unsaturated (mono-enoic)
οƒœ having a single double bond.

Polyunsaturated (poly-enoic)
οƒœ with 2 or more double bonds.

146
Q

What are examples of saturated fatty acids?

A

Acetic 2

Butyric 4

Caproic 5

Palmitic 16

Stearic 18

Propionic 3

Valeric 5

147
Q

What are the examples of monounsaturated fatty acids?

A

Palmitoleic (16: 1βˆ†9, W7)

Oleic (18: 1βˆ†9, W9)

Nervonic (24: 1βˆ†15, W9)

148
Q

What are the common sources for mono-unsaturated fatty acids?

A

3S-2C-ON

❖ Common sources: Many vegetable oils: sunflower, olive, nuts, corn, sesame, soybean, and cod liver oils.

149
Q

What are the poly-unsaturated fatty acids (PUFA)?

A

❖ They are fatty acids that contain more than one double bond.
❖ They must be taken into the diet because the body cannot synthesize them as the enzymes
needed for their synthesis are absent in humans.

150
Q

What are the common sources for PUFA?

A

Many vegetable oils: sunflower, olive, nuts, corn, soybean, and cod liver oils.

151
Q

What is the Importance of essential fatty acids (PUFAs)?

A

 They are essential for growth.
 They are essential for phospholipid formation
 Important for prostaglandins biosynthesis.

152
Q

What are examples of PUFAs?

A

Linoleic (18: 2βˆ†9,12, W6)
Linolenic (18: 3βˆ†9,12,15, W3)
Arachidonic. (20: 4βˆ†5,8,11,14, W6)

153
Q

What are simple lipids?

A

They are esters of fatty acids with various alcohols. The alcohol may be glycerol or other than glycerol.

154
Q

What are simple lipids classified into?

A

They are classified into fats, oils, and waxes, according to the type of alcohol they contain.

155
Q

What are the other names for fats and oils?

A

(triglycerides = triacylglycerol)

156
Q

What are triglycerides?

A

They are esters of fatty acids with glycerol.

The fatty acids may be the same forming simple triglycerides e.g. palmitic or stearic
acids forming tripalmitate or tristearate respectively, or they may be different forming mixed triglycerides with 3 different fatty acids.

157
Q

Why are triglycerides called by this name?

A

because they are triesters formed of glycerol and 3 fatty acids

158
Q

What is the function of triglycerides?

A

1) Storage of energy as fat:
 The triacylglycerols are the storage form of lipids in the adipose tissue.

2) Provide essential fatty acids.

3) Carriers of fat-soluble vitamins (A-D-E-K).

159
Q

What are waxes?

A

They are esters of fatty acids with a long-chain monohydric alcohol.

160
Q

What are examples of waxes?

A

-The most commonly known animal wax is beeswax
-One of the most important waxes in plasma and tissues is cholesterol esters (cholesterol wax).
-Cerumen (earwax) from the ceruminous glands in ears.

161
Q

What are Compound (Conjugated) Lipids?

A

❖ Fatty acids + alcohol + other groups.
❖ They are classified according to the other group into:

οƒœ Phospholipids: phosphoric acids
οƒœ Glycolipids: Sugars
οƒœ Sulfolipids: sulfate
οƒœ Lipoproteins: proteins

162
Q

What is the structure of phospholipids?

A

❖ Alcohol + fatty acids + phosphoric acid Β± nitrogenous base.

163
Q

What are the types of phospholipids?

A

Glcrolphospholipids (phosphoglycerides) : Glycerol

Sphingophospholipids (sphingomyelin) : Sphingol (sphingosine)

164
Q

What are examples of glycerophospholipids (phosphoglycerides)?

A
  1. phosphatidic acid: Glycerol + 2 fatty acids +Phosphoric acid (No base)
  2. Lecithin (Phosphatidylcholine): Phosphatidic acid + choline base.
  3. Cephalin (phosphatidylserine or ethanolamine) :phosphatidic acid + serine or ethanolamine
  4. Phospatidyl Inositol (Lipoinositol): phosphatidic acid + Inositol.
165
Q

What is the structure of sphingophospholipids?

A

❖ Sphingol + unsaturated fatty acid + phosphoric acid + choline.

166
Q

What is the function of phospholipids?

A

They are amphipathic (hydrophilic part + hydrophobic part) which helps:
 Formation of the lipid bilayer in the cell membrane.
 Micelle formation to help T.G absorption in the small intestine
 The structure of plasma lipoprotein carries lipids in the blood.

2) Di-palmitoyl lecithin (DPL) is a component of lung surfactant (prevent lung collapse).

3) Lecithin is a lipotropic agent (prevent fatty liver).

4) Membrane phospholipids provides arachidonic acid for the synthesis of prostaglandins,
leukotrienes.

5) Essential for blood clotting as platelet-activating factor (PAF) is choline plasmalogen

6) Phosphatidylinositol bisphosphate (PIP2) is 2nd messenger for hormones.

7) sphingomyelin is present in myelin sheath around nerves (electrical insulator

167
Q

What is the structure of glycolipids?

A

❖ Fatty acids + alcohol + sugar

168
Q

What are glycolipids classified into?

A

-cerebrosides: ❖ sphingol+ fatty acid +monosaccharide usually galactose (Galacto-cerebrosides), may be glucose (Gluco-cerberosides)

-gangliosides: ❖ sphingol + fatty acid + oligosaccharide chain

169
Q

What is the function of gangliosides?

A

-Electrical insulator in nervous tissue.
-Gangliosides are receptors for many hormones

170
Q

What is the structure of sulpholipids?

A

as cerebrosides + sulfate group at C3 of galactose

171
Q

What is the function of sulpholipids?

A

present in the brain and nervous tissue.

172
Q

What are Lipoproteins formed of?

A
  • lipid part (Triglycerides T.G, cholesterol, phospholipids)
  • protein part (Apolipoprotein, may be Ξ± or Ξ² globulin)
173
Q

What is the function of Lipo proteins?

A
  • Structure of cell membrane
  • Lipid transport in the blood.
174
Q

What are the types of Lipo proteins?

A

1) Chylomicrons (CM)

2) Very Low-Density Lipoprotein (VLDL)

3) Low Density Lipoprotein (LDL)

4) High Density Lipoprotein (HDL)

175
Q

Compare between chylomicrons, VLDL, LDL and HDL

A
176
Q

What are derived lipids?

A

Lipids derived from simple lipids and compound lipids by hydrolysis (fatty acids, alcohol) or related to lipids (steroids)

177
Q

What are steroids?

A

Large group of biologically important compounds contain steroid nucleus.

178
Q

What do steroids include?

A

They include:
1) Sterols
2) Steroid hormones
3) Vitamin D
4) Bile acids

179
Q

What are sterols?

A

Cholesterol and ergosterol

180
Q

Compare between cholesterol and ergosterol

A
181
Q

What are the sources of cholesterol?

A

Exogenous (dietary cholesterol):
- butter, cream, milk, egg yolk, and meat.

Endogenous: Synthesized in the body

182
Q

What are the sites (occurrence) of cholesterol?

A
  • It is widely present in body tissues.
  • largest amounts in brain, liver, skin, small intestinal, and adrenal
    cortex
183
Q

What is a normal level of blood cholesterol?

A

Normal level of total cholesterol is below 200 mg/dl.

184
Q

What is hypercholesteremia associated with?

A

atherosclerosis, myocardial infarction and cerebral stroke.

185
Q

What are the forms of blood cholesterol?

A
  • Free Cholesterol
  • Cholesterol ester (70%), linked with fatty acids

(75% of cholesterol is carried in LDL, the reminder in HDL)

186
Q

Compare between sex hormones

A
187
Q

What are adrenal cortex hormones (corticoids)?

A

❖ Glucocorticoids (21 C):
- Corticosterone & Cortisol (17-OH corticosterone)

❖ Mineralocorticoids (21 C):
- 11-Deoxy corticosterone (DOC)
- 11 deoxy cortisol
- Aldosterone (most active)

188
Q

What are the forms of vitamin D?

A
  • Vitamin D3: derived from 7-dehydrocholesteorl by U.V rays.
  • Vitamin D 2: derived from ergosterol by U.V rays.
189
Q

What is the function of vitamin D?

A

increase Ca absorption from GIT and increase bone ossification

190
Q

Compare between bile acids

A
191
Q

Formation of bile salts

A

❖ Bile acids unit with glycine (glycocholic acid) or taurine (taurocholic acid).

❖ Glycocholic acid and Taurocholic acid + Na or K β†’ Na or K -glycocholate and taurocholate (bile salts).

192
Q

What is the definition of enzymes?

A

En= inside Zyme=yeast

Enzymes are organic thermo-labile catalysts.

193
Q

What is a catalyst?

A

catalyst is a substance that increases the chemical reaction without change (not consumed, not affect the end product).

They accelerate the chemical reactions inside the biological systems (living cells).

194
Q

What is the chemical nature of enzymes?

A

All enzymes are protein in nature except ribozymes (RNA in nature).

195
Q

What are the types of enzymes?

A

1) Simple protein enzymes: They are formed of protein only.
2) Complex (conjugated) protein enzymes: formed of two parts

196
Q

What are the parts of the complex enzyme?

A

The protein part is called apoenzyme

The Non-protein part is called the cofactor.

The whole enzyme is called a holoenzyme.

197
Q

What is the active site?

A

A restricted region of an enzyme molecule that binds to the substrate.

198
Q

How is the active site formed?

A

It is formed from Amino acids sequences in the polypeptide chain.

199
Q

What is the mechanism of the enzyme action?

A

1) The substrate (S) binds to the enzyme (E) to form an activated intermediate enzyme-substrate complex (ES).
2) The activated complex (ES) cleaved to the products (P) and the original enzyme (E).

200
Q

What does the cofactor do in complex enzymes?

A

In complex enzymes, the coenzyme helps the cleavage of the substrate.

201
Q

What are the enzymatic reaction steps?

A

1) Substrate approaches active site.
2) Enzyme-substrate complex forms.
3) Substrate transformed into products.
4) Products released.
5) Enzyme recycled.

202
Q

What are the theories that explain the E-S complex?

A

Lock and key theory. (Proposed by Fischer in 1894)
Induced fit theory.

203
Q

Lock and key theory (Proposed by Fischer in 1894)

A

❖ In this model, the active sites of the unbound enzyme are complementary (fit) in shape to the substrate.
❖ The substrate fits in this catalytic site in a similar way to lock and key. The key will only fit its own lock.

204
Q

Induced fit theory

A

ο‚΅ It is a more flexible model.

ο‚΅ The catalytic site of the enzyme is not complementary to the substrate.

ο‚΅ The binding of the substrate to the enzyme induces changes in the shape of the catalytic site making it fitter for the substrate.

205
Q

What are the factors affecting the rate of enzyme action?

A

1- Effect of enzyme conc.
2- Effect of substrate conc.
3- Effect of temperature
4- Effect of PH
5- Concentration of coenzymes
6- Concentration of ion activators
7- Presence of enzyme inhibitors
8- Effect of time

206
Q

Th effect of enzyme conc.

A

The rate of enzyme action is directly proportional to the concentration of enzyme provided sufficient supply of substrate & constant conditions.

207
Q

The effect of the substrate conc.

A

The rate of reaction increases as the substrate concentration increases up to a certain point at which the reaction rate is maximal (Vmax.)

At Vmax, the enzyme is completely saturated with the substrate, then any increase in substrate concentration doesn’t affect the reaction rate.

208
Q

What is the Michael is constant (Km)?

A

It is the substrate concentration that produces half the maximum velocity of enzyme (1/2
Vmax).

209
Q

What are enzymes with low Km?

A

have high affinity to the substrate i.e. they act at maximal velocity at low substrate concentration.

210
Q

What are examples of enzymes with low Km?

A

Hexokinase which acts on glucose at low concentration (fasting state)

211
Q

What are enzymes with high Km? And what are their examples?

A

have low affinity to the substrate i.e. they act at maximal velocity at high substrate concentration.

E.g. Glucokinase enzyme acts on glucose at high concentrations (fed state).

212
Q

What is the effect of temperature on the rate of the reaction?

A

ο‚΅ The rate of reaction increases gradually with the rise in temperature until reaches a maximum at a certain temperature, called optimum temperature.

ο‚΅ The optimum temperature is around 37Β°C in humans

ο‚΅ After the optimum temperature, the rate of reaction decreases

213
Q

What does the enzyme activity decrease after a certain point of temperature?

A

due to the denaturation of the enzyme (60-65).

214
Q

Why does the increase in temperature (up to a certain limit) affect the enzyme activity?

A

The effect of temperature on reaction rate is due to:
a)Increase in temperature increases the initial energy of the substrate and thus decreases the activation energy.

b) Increase of collision of molecules.

215
Q

Effect of pH on the enzyme activity

A

Each enzyme has an optimum PH at which its activity is maximal.

Change of PH above or below optimum PH decrease rate of enzyme action

216
Q

Why does Change of PH above or below optimum PH decrease the rate of enzyme action?

A

due to:
1) The enzyme activity depends on the ionization state of both enzyme and substrate which is affected by PH.

2) Marked change in PH will cause denaturation of the enzyme.

217
Q

Concentration of coenzymes

A

In the conjugated enzymes that need coenzymes, the increase in the coenzyme concentration will increase the reaction rate.

218
Q

The concentration of ion activators

A

The increase in metal ion activator increases the reaction rate.

Many enzymes are activated by ions:
1- Chloride ion activate salivary amylase
2- Calcium ions activate the thrombokinase enzyme

219
Q

Presence of enzymes inhibitor

A

presence of enzyme inhibitor decreases or stops the enzyme activity

220
Q

Effect of time

A

In an enzymatic reaction, the rate of reaction is decreased over time.

221
Q

Why does the rate of enzymatic reaction decrease with time?

A

This is due to:
a) The decrease in substrate concentration
b) The accumulation of the products.
c) The change in PH than optimum PH.

222
Q

What is the definition of isoenzymes?

A

Iso = the same

Different molecular forms of the enzyme, have the same
catalytic activity.

223
Q

What are the characters of isoenzymes?

A

Although they have the same catalytic activity, they are physically distinct & differ in:
1) Electrophoretic mobility (migration in an electric field).
2) Liability to inhibitors.

224
Q

What are examples of isoenzymes?

A

οƒœ Lactate dehydrogenase (LDH)
οƒœ Creatine kinase (CK)
οƒœ Acid phosphatase
οƒœ Alkaline phosphatase

225
Q

LDH

A

❖ LDH enzyme is a tetramer formed of (4) protein subunits, each subunit is called protomer.
❖ The subunits of LDH are of 2 types, H (heart) and M (muscle).

226
Q

LDH types

A

LDH 1 HHHH Myocardial infraction

LDH 2 HHHM Myocardial infraction

LDH 3 HHMM Leukemia

LDH 4 HMMM Viral hepatitis

LDH 5 MMMM Viral hepatitis

227
Q

Creatine kinase (CK)

A

❖ CK enzyme is a dimmer formed of 2 protein subunits.
❖ The subunits of CK are of 2 types, B (brain) and M (muscle

228
Q

CK types

A

CK BB BB Brain tumors
CK MB BM Heart diseases
CK MM MM Skeletal muscle diseases

229
Q

What are the sources of isoenzymes?

A

1- True genetic variants (True isoenzyme)
οƒœ may be produced by more than one gene; each gene produces one subunit

2- Multiple forms (post-translational modification)
οƒœ Isoenzymes may be produced by the same gene, but the subunits undergo different post-translation modifications in different organs

230
Q

What is the medical importance of isoenzymes?

A

Isoenzymes are important in the diagnosis of diseases and indication of the diseased organ

231
Q

What are the types of plasma enzymes?

A

❖ Plasma contains many enzymes: Functional and non-functional plasma enzymes

232
Q

Functional plasma proteins Vs. non-functional plasma proteins

A

οƒœ Higher in comparison to tissue
οƒœ Have known functions
οƒœ Always present in plasma
οƒœ Liver
οƒœ They decrease in liver diseases

Ex:-
οƒœ Clotting factors e.g. Prothrombin
οƒœ Lipoprotein lipase
οƒœ Pseudocholinesterase

οƒœ Very low in comparison to tissue
οƒœ No known functions
οƒœ Absent from plasma
οƒœ Different organs e.g. liver, heart, skeletal muscles, and brain
οƒœ They increase in different organ diseases

Ex:-
οƒœ ALT, AST, Alkaline phosphatase
οƒœ Acid phosphatase
οƒœ Lipase

233
Q

What are the sources of non-functional plasma enzymes?

A

❖ Obstruction of the normal pathway.
❖ Increased permeability of cell membrane: as in tissue hypoxia.
❖ Cell damage with the release of its contents of enzymes into the blood.

234
Q

What is the medical importance of non-functional enzymes?

A

ALT: Liver disease
AST: Liver, heart disease
CK: Brain tumors, Myocardial infarction, SM disease
LDH: Myocardial infarction, Leukemia, Viral hepatitis
Alk. Phosphatase: Obstructive liver disease, bone disease
Acid phosphatase: Prostate cancer
Amylase, lipase: pancreatitis

Y1B1 (PAECH & PBBG) πŸ“• (5 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions