BIO202 Final Term Current Paper by Kainat Alvi Arshi

BIOCHEMISTRY -I (BIO202) · CURRENT FINAL PAPER SPRING 2023(25August) · SHORT QUESTIONS(3) · 1) Types of lipoprotein

The lipoprotein particles include

1. chylomicrons (CM),
2. very-low-density lipoproteins (VLDL),
3. low-density lipoproteins (LDL), and
4. high-density lipoproteins (HDL).

2) Components of nucleotides

Nucleotides are composed of three main components:

1. a nitrogenous base (adenine, guanine, cytosine, thymine, or uracil),
2. a pentose sugar (ribose or deoxyribose), and
3. a phosphate group.

These components come together to form the building blocks of nucleic acids like DNA and RNA.

Q3. Write three modified bases?

These unusual bases(also called modified bases) include

1. Dihydrouracil
2. Pseudouridine
3. Thymine.

Q4. Functional group of pyrimidines and purines?

The most important functional groups of pyrimidines and purines are

1. ring nitrogens,
2. carbonyl groups, and
3. exocyclic amino groups.

5) Three names of polyunsaturated fatty acid

Polyunsaturated fatty acids contain more than one double bond • These include:

1. Linoleic acid (18: 2Δ9, 12 )
2. α-Linolenic acid (18 : 3Δ9, 12, 15)
3. Arachidonic acid series (20 : 4Δ5, 8, 11, 14)

6) Enzyme activity in three steps

• Enzyme-catalyzed reactions have three basic steps:

1. binding of substrate: E+S ES
2. conversion of bound substrate to bound product: ES EP
3. release of product : EP E+P

7) Mention inorganic cofactors

The inorganic cofactor involved in coenzymes include:

a. Zinc (Zn) b. Iron (Fe) c. Magnesium (Mg) d. Copper (Cu) e. Manganese (Mn)

Q8. Name Of three pyrimidine

1. Cytosine C—in both DNA and RNA
2. Thymine (T)—only in DNA
3. Uracil (U) —only in RNA
4. Cytosine is 2-oxy-4- amino-pyrimidine
5. Thymine is 2,4-dioxy-5- methyl-pyrimidine
6. Uracil is 2,4-dioxypyrimidine

9) Pepsin PH

pepsin, a digestive enzyme in the stomach, is maximally active at pH 2.

10)

Concentration of tRNA in cell

tRNAs compose roughly 20% of total cellular RNA • There are at least 20 species of tRNA molecules in every cell.

11)

Number of carbon atom in Stearic acid

Stearic acid is a saturated fatty acid, meaning it does not contain any double bonds in its carbon chain. It consists of 18 carbon atoms in total.

12)

Monosaccharides

Monosaccharides (simple sugars) are those which cannot be hydrolyzed further into simpler forms . e.g: Glucose

13)

Polysaccharides with two example

These are complex carbohydrates made up of multiple monosaccharide units. Examples include starch (energy storage in plants), glycogen (energy storage in animals), and cellulose (structural component in plant cell walls).

14)

How fireflies produce light?

The light produced by fireflies is the result of a reaction involving the protein luciferin and ATP, catalyzed by the enzyme luciferase.

15)

Result of reduction of glutamate

• Removal of glutamate residue from LTC4(4 is subscript) forms LTD4 • LTD4 on removal of glycine becomes LTE4

16)

Hypercholesterolemia

"hypercholesterolemia," which is a condition characterized by high levels of cholesterol in the blood. This condition can increase the risk of heart disease and other cardiovascular issues.

17)

Effect of increase in GC base pairs

• The higher the content of GC base pairs, the higher the melting point of the DNA. • This is because GC base pairs, with three hydrogen bonds, require more heat energy to dissociate than AT base pairs.

18)

Enantiomers and diastereomers

Stereoisomers that are mirror images of each other are called enantiomers

Pairs of stereoisomers that are not mirror images of each other are called diastereomers

19)

Diff. B/w Tyrosine Tryptophan and phenyl alanine on ring structure

Tyrosine: Amino acid with phenyl group and hydroxyl (-OH).

Tryptophan: Amino acid with indole ring and nitrogen atom.

Phenylalanine: Amino acid with simple benzene ring.

20)

Cis-isomerism

Cis-isomerism refers to the arrangement of atoms or groups on the same side of a double bond in a molecule. It is important because it affects the physical and chemical properties of the molecule, such as its melting point, boiling point, and reactivity.

21)

Mention the name and symbol of alanine arginine

The name and symbol of alanine are “Alanine” and “Ala” respectively. For arginine, the name and symbol are “Arginine” and “Arg” respectively.

22)

Allosteric hemoglobin

Allosteric hemoglobin refers to the ability of hemoglobin to undergo conformational changes in response to the binding of molecules, such as oxygen or carbon dioxide, at sites other than the active site. This allows for the regulation of oxygen binding and release in different tissues.

23)

Eicosanoid

Eicosanoids are a large group of lipid messengers with potent effects on every tissue in the body. Eicosanoids are derived from metabolism of 20carbon, polyunsaturated fatty acids (eicosanoic acids). Eicosanoids are derived from either Omega-3 (ω-3) or Omega-6 (ω-6) fatty acids. Arachidonic acid is the most common precursor of the eicosanoids.

24)

Structure of the amino acid

The structure of an amino acid includes a central carbon atom (α-carbon) bonded to an amino group (NH2), a carboxyl group (COOH), a hydrogen atom (H), and a variable side chain known as the R group. The R group determines the specific characteristics of each amino acid.

25)

Bond between DNA strand

The bond that holds the two strands of DNA together is a hydrogen bond. These hydrogen bonds form between complementary nitrogenous bases: adenine (A) with thymine (T) and cytosine (C) with guanine (G). This base pairing is a key structural feature of the DNA double helix.

26) · What is simple lipids discuss its two types · Simple lipids:

Esters of fatty acids with various alcohols

These contain:

a. Fats (and Oils) and b. Waxes.

Fats: Esters of fatty acids with glycerol (Oils are fats in the Liquid state)

Waxes: Esters of fatty acids with higher molecular weight monohydric alcohols. (having one OH group)

27)

Waxes

Esters of fatty acids with higher molecular weight monohydric alcohols(having one OH group).

28)

Types of waxes

• Waxes are of two types:

1. True Waxes • Waxes are solid, simple lipids containing a monohydric alcohol (with a higher molecular weight than glycerol)
2. Other Waxes or Non true waxes • include esters of: • Cholesterol • Vitamin A • Vitamin D

29)

Bees wax and spermaceti

• Waxes are widely distributed in nature such as the secretion of certain insects as; • Bees-wax, • Spermaceti of the sperm whale

Bees-wax is secreted by the honeybees that use it to form the combs. • It is a mixture of waxes • chief constituent is myricyl (30C ), palmitate (16C )

Spermaceti is a wax that is primarily found in the head cavities of sperm whales. It consists of fatty esters, mainly cetyl palmitate and cetyl myristate. Spermaceti has been used in cosmetics, pharmacy, and candles, but its use has been restricted due to international regulations on whale captures. Synthetic cetyl palmitate is now used as a replacement.

30)

Five properties of waxes

o Waxes are insoluble in water, but soluble in fat o Solvents and are negative for acrolein test. o Very resistant to rancidity. o Waxes are not easily hydrolyzed as the fats o waxes are indigestible by lipases (enzymes responsible for fat Digestion in body) Thus they are of no nutritional value

31)

what is sterol & write example

Sterols are a type of lipid that have a specific structure, including a four-ring core. They are found in cell membranes and are important for maintaining membrane fluidity and stability. Cholesterol is a well-known example of a sterol, which is found in animal cell membranes and serves various functions in the body, including hormone synthesis and cell signaling.

32)

Cholesterol amphiphilic or amphipathic

" Amphipathic" and "amphiphilic" are often used interchangeably to describe molecules that have both hydrophilic and hydrophobic regions in their structure. Cholesterol is considered amphiphilic, as it has both hydrophilic (water-attracting) and hydrophobic (water-repelling) parts in its molecular structure. This characteristic enables it to interact with both water-soluble and lipid-soluble molecules in biological systems.