NUCLEOTIDES

Question 1

______ are long chains of repeated nucleotides

Answer 1

Nucleic acids (DNA and RNA)

Question 2

Nucleic acids are formed by the combination of nucleotide molecules through

Answer 2

sugar-phosphate

bonds known as phosphodiester linkages

Question 3

A nucleotide consists of:

Answer 3

o Nitrogenous base
o Pentose sugar
o One or more phosphate groups

Question 4

They are monomeric units of nucleic acids and also serve as sources of chemical energy (ATP,
GTP), participate in cellular signalling (cAMP, cGMP) and function as important cofactors of
enzymatic reactions (coA, FAD, FMN, NAD+)

Answer 4

NUCLEOTIDES

Question 5

The molecule without the phosphate group of nucleotides is called as ____.

Answer 5

nucleoside

Question 6

___ are glycosylamines consisting simply of a nitrogenous base and a five-carbon sugar (either ribose or deoxyribose)

Answer 6

Nucleosides

Question 7

With all three joined, a nucleotide is also termed a

Answer 7

“nucleoside phosphate”

Question 8

The nitrogenous base is either a

Answer 8

purine or a pyrimidine.

Question 9

There are ___ major bases found in cells.

Answer 9

five

Question 10

The derivatives of purine are called

Answer 10

adenine and guanine

Question 11

derivatives of pyrimidine are called

Answer 11

thymine, cytosine and uracil.

Question 12

Purines include adenine and guanine and have

Answer 12

two rings

Question 13

Adenine has an _____ group on its rings, whereas guanine has a ___ group.

Answer 13

ammonia

ketone

Question 14

Pyrimidines include cytosine, thiamine, and uracil and have ____.

Answer 14

one ring

Question 15

Thymine (found in DNA) and uracil (found in RNA) are

Answer 15

similar in that they both have

ketone groups, but thymine has an extra methyl group on its ring.

Question 16

Bonds between guanine and cytosine (three hydrogen bonds) are stronger than

Answer 16

bonds between adenine and thymine (two hydrogen bonds).

Question 17

The five-carbon sugar is either a

Answer 17

ribose (in RNA) or a deoxyribose (in DNA) molecule.

Question 18

In nucleotides, both types of pentose sugars are in their

Answer 18

beta-furanose (closed five- membered ring) form.

Question 19

PROPERTIES OF NUCLEOTIDES

Answer 19

 Sparingly soluble in water
 Absorb light in UV region at 260 nm. 
 Capable of forming hydrogen bond
 Aromatic base atoms numbered 1 to 9
 Purine ring is formed by fusion of pyrimidine ring with imidazole ring

Question 20

STRUCTURE OF NUCLEOSIDES

Answer 20

In a nucleoside, the base is bound to either ribose or deoxyribose via a beta-glycosidic linkage at 1’ position.

Examples of nucleosides include cytidine, uridine, adenosine, guanosine, thymidine and inosine.

Question 21

PROPERTIES OF PYRIMIDINE BASES

Answer 21

 Soluble at body pH
 Also absorb UV light at 260 nm
 Capable of forming hydrogen bond
 Aromatic base atoms are numbered 1 to 6 for pyrimidine.
 Atoms or group attached to base atoms have same number as the ring atom to which they are bonded.

Question 22

PROPERTIES OF PENTOSE SUGARS

Answer 22

 A pentose is a monosaccharide with five carbon atoms.

Question 23

is the most common pentose with one oxygen atom attached to each carbon atom.

Answer 23

Ribose

Question 24

Deoxyribose sugar is derived from the

Answer 24

sugar ribose by loss of an oxygen atom.

Question 25

The aldehyde functional group in the carbohydrates react with neighbouring hydroxyl functional groups to form

Answer 25

intramolecular hemiacetals.

Question 26

The resulting ring structure is related to furan, and is termed a

Answer 26

furanose

Question 27

The ring spontaneously opens and closes, allowing rotation to occur about the bond between the carbonyl group and the neighboring carbon atom yielding two distinct configurations (α and β). This process is termed

Answer 27

mutarotation.

Question 28

___ if the sugar is ribose.

Answer 28

Ribonucleotides

Question 29

if the sugar is deoxyribose.

Answer 29

Deoxyribonucleotides

Question 30

``` Located in the nucleus of the cell and self- replicating ```

Answer 30

DNA

Question 31

Storage form of genetic information

Answer 31

DNA

Question 32

Base pairing is AT and GC

Answer 32

DNA

Question 33

``` Copied from DNA and is working form of the information ```

Answer 33

RNA

Question 34

``` Made in the nucleus and mRNA is exported to the cytosol ```

Answer 34

RNA

Question 35

Base pairing is | AU and GC

Answer 35

RNA

Question 36

Adenosine nucleotides:

Answer 36

ATP, ADP, AMP, Cyclic AMP

Question 37

Guanosine nucleotides:

Answer 37

GTP, GDP, GMP, Cyclic GMP

Question 38

Cytidine nucleotides:

Answer 38

CTP, CDP, CMP and certain deoxy CDP derivatives of glucose, choline and ethanolamine

Question 39

Uridine nucleotides:

Answer 39

UDP

Question 40

Miscellaneous :

Answer 40

PAPS (active sulphate), SAM (active methionine), certain coenzymes like NAD+, FAD, FMN, Cobamide coenzyme, CoA

Question 41

The ____are of great importance to living organisms, as they are the building blocks of nucleic acids, the substances that control all hereditary characteristics.

Answer 41

nucleotides

Question 42

consist of nucleosides joined by 3′,5′-phosphodiester bridges. The genetic message resides in the sequence of bases along the polynucleotide chain.

Answer 42

Polynucleotides

Question 43

have a variety of roles in cellular metabolism. They are the energy currency in metabolic transactions.

Answer 43

Nucleotides

Question 44

They act as essential chemical links in the response of cells to hormones and other extracellular stimuli.

Answer 44

NUCLEOTIDES

Question 45

They are the structural components of an array of enzyme cofactors and metabolic intermediates.

Answer 45

NUCLEOTIDES

Question 46

The structure of every protein, and ultimately of every biomolecule and cellular component, is a product of information programmed into the

Answer 46

nucleotide sequence of a cell’s nucleic acids.

Question 47

Serving as energy stores for future use in phosphate transfer reactions. These reactions are predominantly carried out

Answer 47

ATP.

Question 48

A cell’s hereditary information is encoded in in the cell’s nucleus.

Answer 48

chromosomes

Question 49

Each chromosome is composed of

Answer 49

proteins and deoxyribonucleic acid (DNA).

Question 50

The chromosomes contain smaller hereditary units called ___, which are relatively short segments of DNA.

Answer 50

genes

Question 51

The hereditary information is expressed or used through the synthesis of

Answer 51

ribonucleic acid (RNA).

Question 52

Both nucleic acids—DNA and RNA—are polymers composed of monomers known as ___, which in turn consist of phosphoric acid (H3PO4), a nitrogenous base, and a pentose sugar.

Answer 52

nucleotides

Question 53

RNA is a single-chain nucleic acid, whereas DNA possesses two nucleic-acid chains intertwined in a secondary structure called a

Answer 53

double helix.

Question 54

Hydrogen bonding between ___ holds the two strands of the double helix together; A always pairs with T and C always pairs with G.

Answer 54

complementary bases

Question 55

Cell growth requires ____ of the cell’s DNA.

Answer 55

replication, or reproduction

Question 56

For protein synthesis, three types of RNA are needed: messenger RNA (mRNA), ribosomal RNA (rRNA), and transfer RNA (tRNA). All are made from a DNA template by a process called

Answer 56

transcription

Question 57

is the process in which proteins are synthesized from the information in mRNA.

Answer 57

Translation

Question 58

It occurs at structures called ___, which are located outside the nucleus and are composed of rRNA and protein.

Answer 58

ribosomes

Question 59

The ____ possible three-nucleotide combinations of the 4 nucleotides of DNA constitute the ____ that dictates the sequence in which amino acids are joined to make proteins.

Answer 59

64 genetic code

Question 60

Each three-nucleotide sequence on mRNA is a ___.

Answer 60

codon

Question 61

Each kind of tRNA molecule binds a specific amino acid and has a site containing a three- nucleotide sequence called an anticodon.

Answer 61

ANTICODON

Question 62

The general term for any change in the genetic code in an organism’s DNA is ___.

Answer 62

mutation

Question 63

A change in which a single base is substituted, inserted, or deleted is a

Answer 63

point mutation

Question 64

The chemical and/or physical agents that cause mutations are called

Answer 64

mutagens

Question 65

Diseases that occur due to mutations in critical DNA sequences are referred to as

Answer 65

genetic diseases

Question 66

The 5’terminus of mRNA is “capped” with a

Answer 66

methylated base of Guanosine 5’ triphosphate.

Question 67

The length of tRNAs ranges from

Answer 67

65-110 nucleotides with a corresponding molecular weight of 22, 000-37500 Daltons.

Question 68

The __ is a single stranded.

Answer 68

tRNA

Question 69

___ are found associated with large number of proteins in an ordered complex.

Answer 69

Ribosomal RNA

Question 70

has a helical structure resulting from the folding back of single stranded polymer and constitute about 74-80% of total RNA in a cell.

Answer 70

Ribosomal RNA

Question 71

are synthesized in cytoplasm of most of the tissues.

Answer 71

Purine nucleotides

Question 72

The major site for purine | synthesis is

Answer 72

liver

Question 73

Since purine ring are synthesized from different small components, they are makorly denoted by

Answer 73

de novo synthesis

Question 74

(PRPP)

Answer 74

Phospho ribosyl phyrophosphate

Question 75

(APRTase)

Answer 75

Adenine phosphor ribosyl transferase

Question 76

(HGPRTase)

Answer 76

Hypoxanthine guanine phosphoribosyl transferase

Question 77

The most common abnormality of purine metabolism is

Answer 77

elevation of uric acid level in blood.

Question 78

Elevated level of uric acid in blood is called as

Answer 78

hyper-uricemia

Question 79

In hyperuricemia the serum uric acid level | exceeds the level of

Answer 79

7 mg/dl for male and 6 mg/dl in female.

Question 80

This increased uric acid may or may not be | excreated via urine and the condition is called as

Answer 80

uricosuria