1mark

Question 1

Which is true according to chargaff’s rule?

Answer 1

A+G=T+C

Question 2

Sugar-phosphate chains in DNA acts as

Answer 2

Backbone

Question 3

Number of base pairs in the haploid content of Human DNA is

Answer 3

3.3×10⁹bp

Question 4

Information flow of central dogma in biology is

Answer 4

DNA–>RNA–>proteins

Question 5

Radioactive element used to label DNA of bacteriophage in experiment of hershey and chase was

Answer 5

S³⁵

Question 6

RNA is less stable genetic material as compared to DNA, the reason for this

Answer 6

●In RNA 2’ position of -OH group is present while DNA does not have
●RNA is known to be catalytic
●RNA has uracil where as DNA has thymine

Question 7

Transcriptionally active chromatin is

Answer 7

Euchromatin

Question 8

Okazaki fragments are formed on one of the strands of DNA known as

Answer 8

Lagging strand

Question 9

mRNA in prokaryotes is usually

Answer 9

Polycistronic

Question 10

Which is a starter codon?

Answer 10

AUG

Question 11

Aminoacylation of tRNA is essential for

Answer 11

Formation of peptide bond

Question 12

The lac operon of E.coli contains genes involved in lactose metabolism. It is expressed only when lactose is ________ and glucose is __________

Answer 12

Present, absent

Question 13

A nitrogeneous base is linked to the OH of 1’C pentose sugar through ___________ linkage to form a nucleoside

Answer 13

N-glycosidic

Question 14

Histones are rich in basic amino acid residues

Answer 14

Lysine and arginine

Question 15

___________ is said to be transcriptionally active chromatin, whereas heterochromatin is inactive

Answer 15

Euchromatin

Question 16

The ________________ of ‘transforming principle’in griffith’s experiment was determined by Oswald avery, colin macleod and maclyn Mc Carty

Answer 16

Biochemical nature

Question 17

_____________ and _____________ performed an experiment in 1958 and proved the semi conservative replication of DNA

Answer 17

Matthew meselson and Franklin stahl

Question 18

A failure in cell division after DNA replication results into

Answer 18

Polyploidy

Question 19

DNA dependent RNA polymerase catalyse the polymerisation in only one direction ________

Answer 19

5’–>3’

Question 20

Some amino acids are coded by more than one codon hence the code is

Answer 20

Degenerate

Question 21

Point mutation is a change of single base pair in the gene for beta globin chain that results in the change of amino acid residue glutamate to ______ which results into a disease called as sickle cell anemia

Answer 21

Valine

Question 22

A polycistronic structural gene is regulated by a common promoter and regulatory genes. Such arrangement is reffered to as ________

Answer 22

Operon

Question 23

Which RNA is also called adapted molecule?

Answer 23

Transfer RNA(t-RNA)

Question 24

Define transcription

Answer 24

The process of copying of genetic information from one strand of DNA into RNA is called transcription

Question 25

What is elution?

Answer 25

The separated bands of DNA are cut off from the arose gel and extracted from the gel piece. This step is known as elution

Question 26

Define translation

Answer 26

The formation of polypeptide by the polymerisation of amino acids is called translation

Question 27

What is the total number of genes in chromosome Y?

Answer 27

231

Question 28

How does exons differ from introns?

Answer 28

The exons are coding or expressed sequences whereas introns are non coding sequences present in RNA

Question 29

Give an example for a non pathogenic nematode whose genome has been completely sequenced.

Answer 29

Caenorhabditis elegans

Question 30

Which chromosome of humans has the most number of genes?

Answer 30

Chromosome 1(2968)

Question 31

Name the linkage between nitrogenous base and pentose sugar in DNA

Answer 31

N-glycosidic linkage

Question 32

How do introns differ from exons?

Answer 32

Introns are non coding sequences whereas exons are coding sequences in m-RNA

Question 33

Genetic code is degenerate. Give reason.

Answer 33

Some amino acids are coded by more than one codon therefore genetic code is said to be degenerate

Question 34

RNA splicing is necessary in eukaryotes. Give reason

Answer 34

RNA splicing helps in removal of non functional introns and joining of exons present in the newly formed hnRNA to make it a functional m-RNA

Question 35

Why DNA replication is termed as semiconservative?

Answer 35

During DNA replication each daughter DNA retains one parental strand and other strand is newly formed hence DNA replication is semiconservative

Question 36

Eukaryotic genes are called split genes. Why?

Answer 36

The structural genes in eukaryotes have interrupted coding sequences

Question 37

Structural genes in prokaryotes are called polycistronic. Give reason

Answer 37

Prokaryotic genes code for many proteins or polypeptides during protein synthesis

Question 38

Wy t-RNA is called an adaptor molecule?

Answer 38

t-RNA has an amino acid accepter and there by binds to amino acids and carry them to ribosomes during protein synthesis

Question 39

How does repressor protein prevent the transcription of structural genes?

Answer 39

Respressor protein binds to the operator region of the operon and prevents RNA polymerase from transcribing to the operon

Question 40

Define replication

Answer 40

The process by which DNA produces its own copy(daughter DNA) is called replication