Nucleotides

Question 1

A glycosidic bond?

Answer 1

Bond between a sugar and another group

Question 2

Ester bond

Answer 2

C-O-R

Question 3

Purine?

Answer 3

Fused 5 and 6 memebered rings

Question 4

Pyrimidine

Answer 4

6 membered rings

Question 5

In purines, N … forms glycosidic bond. In pyrimidines, N … forms

Answer 5

9, 1

Question 6

Structure of pyrimidines

Answer 6

TUC
Thymine has double bonded O at position 2, 4 and Ch3 and 5

Uracil has no CH3 at position 5

Cytosine has no CH3 either had NH2 instead at position 4

Counting starts form nitrogen at extreme bottom.

Question 7

Purine structure

Answer 7

Counting starts from top left and down

Adenine has nh2 at position 6

Guanine has nh2 at position 2 and and o at position 6

AG

Question 8

Phosphate groups linked to

Answer 8

5’ or 3’ carbon

Question 9

Common Adenosine derivatives

Answer 9

ATP
3' 5' Cyclic Adenosine monophosphate
Flavin Adenosine Dinucleotide( FAD and FMN)
Nicotinaminde Adenosine Dinucleotide 
S- adenoysylmethionine

Question 10

Funtions of ATP

Answer 10

Energy storage and transfer, release of third phosphate to produce ADP. ADP releases energy for cell activity

Question 11

What is an analogue

Answer 11

Organic chemical compound related to another by substitution of atoms with other groups

Question 12

Anti tumour agents used in chemotherapy

Answer 12

Interfere with DNA synthesis and kill rapidly dividing cells such as tumour cells

6 mercaptopurine
5 fluorouracil

Question 13

Note

Answer 13

Some analogs inhibit the synthesis of purines and pyrimidines and so biosynthesis of dna. Clinically active in cancer treatment

Question 14

Gour, caused by an accumulation of uric acid is treated by a base analog called

Answer 14

Allopurinol which is a structural analog of hypoxanthine

Question 15

Biomedical importance of nucleotides

Answer 15

Storage and transfer of energy
Precursors of nucleic acids
Storage and transfer of genetic information, DNA and RNA
Components of important coenzimes like NAD and fAD and conenzyme A

Question 16

Order of stability of nucleotides

Answer 16

dA, dG < rA, rG < dC, dT < rC, rU

Question 17

Palindromic sequence

Answer 17

sequence on a double stranded DNA or RNA where 5’ to 3’ reading forwards in one strand matches the sequence reading in same direction on complementary strand with which it forms double helix

Recognized by restriction enzyemee. Restriction enzymes cut DNA at palindromic sequences

Question 18

Mendelian inheritance

Answer 18

Manner in which a particular genetic trait or disorder is passed on from one generation to the next generation

Question 19

Types of inheritance

Answer 19

Autosomal

Sex linked

Question 20

Autosomal inheritance pattern

Answer 20

Inheritance pattern in which the transmission of traits depends on the presence of absence of certain alleles on autosomes

Question 21

Autosomal Dominant Disease Inheritance

Answer 21

Patterm of inheritance in which the transmission of a dominant allele on an autosome causee a trait to be expressed

Question 22

Examples of autosomal dominant diseases

Answer 22

Achrondroplasia

Huntington’s disease

Question 23

Huntington’s disease is…

Answer 23

Progressive brain disorder caused by a single defective gene on chromosome 4

Question 24

Neurofibromatosis ?

Answer 24

Growth of noncancerous tumors called neurofibromas on the nerves
Caused by a mutation in the NF1 gene on chromosome 17

Question 25

Achrondoplasia

Answer 25

Short limbed dwarfism. Point mutation of FGFR3 on chromosome 4
Negative controller of bone growth. Super activity causes bone growth arrest

Question 26

Autosomal recessive inheritance

Answer 26

Pattern of inheritance resulting from the transmission of a recessive allele on an autosome

Question 27

Examples of autosomal recessive disorders

Answer 27

Galactosemia
Tay sach’s disease
Phenulketonuria
Sicke cell disease

Question 28

Tay Sachs disease

Answer 28

Progressively destroys nerve cells in brain and spinal cord. Caused by absence of hexosaminidade A on chromosome 15

Question 29

Galactosemia

Answer 29

Lack of enzyme GALT.

Galactose concentration rises causing kidney failure, cataracts, enlarged liver, etc..

Question 30

Galt gene found on chromosome…?

Answer 30

Chromosome 9

Question 31

Phenylketornuria

Answer 31

Affeects the way the body breaks down protein. Destructive to nervous system and causes intellectual disability

Question 32

Phenylketonuria caused by mutation in

Answer 32

PAH gene on chromosome 12

Question 33

Sickle cell anemia

Answer 33

Xaused by mutation of haemiglobin beta gene on chromosome 11

Question 34

Cyclic AMP functions

Answer 34

1. Second messenger in signal transduction

2. regulate metabolism.

Question 35

Conenzyme a function

Answer 35

Coenzyme serving as acyl group in certain enzymatic reactions

Question 36

S adenosylmethionine function

Answer 36

Methyl CH3 donor in methylation reactions

Question 37

Ribothymidine

Answer 37

Role in thermal stability of trna

Question 38

Nucleotide analogues are prepared by

Answer 38

Altering the base ring or sugar moiety

Question 39

Function of azidothymidine

Answer 39

Use to interfere with replication of viruses by terminating DNA synthesis