MB

Question 1

what is molecular biology ?

Answer 1

field ofscienceconcerned with studying the chemical structures and processes of biological phenomena that involve the basic units of life

Question 2

molecular biology especially focused on what ?

Answer 2

nucleic acids(e.g.,DNAandRNA)

proteins—macromolecules

Question 3

The central dogma of molecular biology states, that genetic material is transcribed into RNA and then translated into protein.

Answer 3

فهم

Question 4

what The compounds produced by living organisms called ?

Answer 4

biochemicals

Question 5

what is the four categories that macromolecules divided into ?

Answer 5

proteins
nucleic acids
polysaccharides,
certain lipids

Question 6

proteins, nucleic acids, polysaccharides are polymers composed of a large number of lowmolecular‐weight building blocks,

Answer 6

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Question 7

what is the process that
macromlecules constructed by ?

Answer 7

polymerization

Question 8

Each monomer is first activated by
attachment to a carrier molecule that helps the monomer to chemically react with the end of the growing macromolecule

Answer 8

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Question 9

A macromolecule is disassembled by hydrolysis of the bonds that join the monomers together

Answer 9

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Question 10

what is the hydrolysis ?

Answer 10

is the splitting of a bond by water.

Question 11

Macromolecules reactions are catalyzed by what ?

Answer 11

enzymes

Question 12

what are the low‐molecular‐weight precursors that are ready to be incorporated into macromolecules ?

Answer 12

Sugars, which are the precursors of polysaccharides;
Amino acids, which are the precursors of proteins;
Nucleotides, which are the precursors of nucleic acids;
Fatty acids, which are incorporated into lipids

Question 13

what is the metabolic intermediates ?

Answer 13

The compounds that formed along the pathways leading to the end products that have no function

Question 14

examples of Molecules of miscellaneous function ?

Answer 14

vitamins, which function
primarily as materials to proteins

certain steroid or amino acid hormones

molecules involved in energy storage, such as ATP

urea

cyclic AMP

Question 15

what is vitamin A function ?

Answer 15

required for the formation of rhodopsin, a photoreceptor pigment in the eye

Question 16

Cyclic AMP

Answer 16

allow the mobilization of glucose from glycogen.

Question 17

Carbohydrates function ?

Answer 17

work as stores of chemical energy

work as durable building materials for biological construction

Question 18

Most sugars have the general formula (CH2O)n . The sugars of importance in cellular metabolism have values of n that range from 3 to 7

Answer 18

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Question 19

Sugars can be joined to one another by covalent glycosidic bonds

Glycosidic bonds form by reaction between carbon atom C1 of one sugar and the hydroxyl group of another sugar, generating a
-C- O- C- linkage between the two sugars.

Oligosaccharides are particularly important on the glycolipids and glycoproteins of the plasma membrane,

Answer 19

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Question 20

Sucrose and lactose are two of the most common disaccharides. Sucrose is composed of glucose and fructose joined by an α (1 → 2) linkage, whereas lactose is composed of glucose and
galactose joined by a β (1 → 4) linkage

Answer 20

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Question 21

Bernard concluded what ?

Answer 21

food materials were carried to the liver where they were chemically converted to glucose and stored as glycogen.

Question 22

In Bernard ’ s hypothesis, the balance between glycogen formation and glycogen breakdown in the liver was the prime determinant in maintaining the relatively constant level of glucose in the blood.

Answer 22

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Question 23

what is the lipids ?

Answer 23

a diverse group of nonpolar biological molecules.

Question 24

some common properties of the lipids ?

Answer 24

ability to dissolve in organic solvents

 inability to dissolve in water

Question 25

Lipids of importance in cellular function ?>

Answer 25

Fats
Steroids
Phospholipids

Question 26

Fats( triacylglycerol ) consist of what ?

Answer 26

Glycerol molecule
Three fatty acids

Question 27

what is the bonds between The glycerol moiety and carboxyl groups
of three fatty acids ?

Answer 27

linked by three ester bond

Question 28

Fats are very rich in chemical energy; a gram of fat contains over twice the energy content of a gram of carbohydrate. Carbohydrates function primarily as a shortterm, rapidly available energy source, whereas fat reserves store energy on a long‐term basis

Answer 28

.

Question 29

what is the adipocytes ?

Answer 29

special cells whose cytoplasm is filled
with one or a few large lipid droplets

Question 30

Adipocytes exhibit a remarkable ability to change their volume to accommodate varying quantities of fat.

Answer 30

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Question 31

Steroids are built around a characteristic four‐ringed hydrocarbon skeleton

Answer 31

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Question 32

Cholesterol function ?

Answer 32

component of animal cell membranes and a precursor for the synthesis of a number of steroid hormones, such as testosterone, progesterone and estrogen

Question 33

The molecule of phospholipids resemble
A fat (triacylglycerol), but has only two fatty acid chains rather than three; it is a diacylglycerol .
The third hydroxyl of the glycerol backbone is covalently bonded to a phosphate group, which in turn is covalently bonded to a small polar group, such as choline, as shown in Figure.

Answer 33

فهم

Question 34

the three groups of amino acids ?

Answer 34

Essential amino acids
Nonessential amino acids
Conditional amino acids

Question 35

what is PKU ?

Answer 35

an inherited metabolic disease in which the body can’t change one essential amino acid

I t is inherited from parents due to a mutated PAH (phenylalanine hydroxylase) gene on chromosome 12

Question 36

Symptoms of PKU ?

Answer 36

Light hair, eyes, and skin
Eczema-like rash
Seizures
Hyperactivity
Unpleasant musty/ mousy body odor
Mental retardation
Phenylketones in urine