Molecular Basis of Inheritance

Question 1

Two types of nucleic acid:

Answer 1

DNA and RNA

Question 2

Base pairs in bacteriophage Φ174:

Answer 2

5386

Question 3

Base pairs in E.coli:

Answer 3

4.6 * 10^6 bp

Question 4

Base pairs in haploid cells:

Answer 4

3.3 * 10 ^ 9 bp

Question 5

Pentose sugar in RNA vs DNA

Answer 5

RNA = Ribose
DNA = Deoxyribose

Question 6

Purines:

Answer 6

Double-ringed (Adenine and Guanine)

Question 7

Pyrimidines:

Answer 7

Single ringed (Uracil, Thymine and Cytosine)

Thymine: 5-methyl uracil

Question 8

Nucleosome:

Answer 8

Histone octamer + DNA

Question 9

Types of chromatin:

Answer 9

Euchromatin and Heterochromatin

Question 10

Griffith’s transforming principle experiment:

Answer 10

(2 strains of streptococcus pneumonia + a mouse)

Question 11

Biochemical characterisation of the transforming principle:

Answer 11

Oswald Avery, McLloyd and McCarty using 3 enzymes: RNAase, DNAase, Protease.

Question 12

Hershey-Chase experiment:

Answer 12

Using a bacteriophage to attack E.coli

Question 13

Organisms with RNA as their genetic material:

Answer 13

Bacteriophages and Tobacco Mosaic Virus.

Question 14

Types of RNA:

Answer 14

• mRNA
• tRNA or sRNA
• rRNA

Question 15

Meselson and Stahl’s experiment:

Answer 15

Using E.coli grown in 2 culture mediums: N15 and N14

Question 16

All the enzymes involved in DNA replication:

Answer 16

• Helicase
• DNA dependent DNA polymerase
• RNA primer (synthesised by Primase)
• DNA ligase
• DNA polymerase

Question 17

Faluire in cell division after replication:

Answer 17

Polyploidy

Question 18

Enzyme that polymerises an RNA

Answer 18

DNA dependent RNA polymerase

Question 19

Template strand:

Answer 19

3’ - 5’

Question 20

Coding strand

Answer 20

5’ - 3’ (used as a reference)

Question 21

3 parts of a transcriptional unit:

Answer 21

• Initiator
• Structural gene
• Terminator

Question 22

Types of structural genes:

Answer 22

• Monocistronic
• Polysistronic

Question 23

Transcriptional steps:

Answer 23

• Initiation
• Elongation
• Termination

Question 24

3 types of RNA polymerase in Eukaryotes:

Answer 24

• RNA polymerase 1 : for rRNA
• RNA polymerase 2: for hnRNA (and mRNA)
• RNA polymerase 3: for tRNA and SnRNA and 55s rRNA

Question 25

Processing of the hnRNA:

Answer 25

• Splicing
• Tailing (adenylate residues in the 3’end)
• Capping ( methyl guanosime triphosphates in the 5’end)

Question 26

Severo Ochoa enzyme:

Answer 26

Polynucleotide phosphorylase (used to polymerise RNA in a template-defined manner)

Question 27

Stop codons:

Answer 27

UAA, UGA, UAG

Question 28

Codon with dual function:

Answer 28

AUG (for methionine and as an initiator)

Question 29

Degenerate codons:

Answer 29

• AUG (for methionine)
• UGG (for tryptophan)

Question 30

The tRNA adapter molecule has:

Answer 30

• An anticodon loop (NODOC)
• Amino acid acceptor end (3’)
• Ribosome binding loop
• Enzyme binding loop

(the stop codons do not have any tRNA)

Question 31

Enzymes associated with Translation:

Answer 31

• Ribozyme (in bacteria)
• aminoacyl tRNA synthetase
• peptidyl transferase

Question 32

Inducer in the lac operon:

Answer 32

Lactose (turns the gene on)

Question 33

Metabolite in the lac operon:

Answer 33

glucose/galactose (turns the genes off)

Question 34

The lac operon is made of:

Answer 34

• inhibitor gene
• structural genes ( y, z and a)
• operator gene

z = beta galactosidase
y = permease
a = transacetylase

Question 35

Duration of the Human Genome project:

Answer 35

1990-2003 (13 years)

Question 36

The HGP was coordinated by:

Answer 36

• U.S Department of Energy
• National institute of Health

Question 37

2 methods of genome sequencing:

Answer 37

• Expressed sequence tags (ESTs)
• Sequence annotation

Question 38

Steps:

Answer 38

Isolation - fragmentation - cloning - sequencing - arranging - alignment

The sequences ar ethen assigned to the 23 chromosomes

(Genetic maps based on polymorphism and repeating DNA sequences called microsatellites)

Question 39

Total no. of base pairs in the human genome:

Answer 39

3,164.7 base pairs

Question 40

Total no. of genes:

Answer 40

30,000 (with 3000 bps each)

Question 41

Largest gene:

Answer 41

Dystrophin on chromosome X

Question 42

Chromosome with most no. of genes:

Answer 42

Chromosome 1

(Least =y)

Question 43

SNPs??

Answer 43

Single-nucleotide polymorphism

Question 44

DNA fingerprinting is also called?

Answer 44

DNA profiling

Question 45

Satellite DNA can be:

Answer 45

• Microsatellites ( VNTR, tandemly repeating units of varying copy no. each unit = 100 bp)
• Minisatellies (STR, each unit = 2-6 bp)

Question 46

DNA polymorphism:

Answer 46

Inheritable hanges/mutations in the nucleotide sequence that can be noticed in a population.

(higher in non-coding DNA)

Question 47

Southern blotting technique

Answer 47

Isolation - digestion - seperation - blotting - hybridisation - detection using autoradiography

Sensitivity of the technique can be amplified through PCR (Polymerase Chain Reactions)

Question 48

Rice genome project application:

Answer 48

• Many mutant variants of rice can be artificially developed.
• It can be used to improve molecular yield
• The rice genome project is an open-access journal dedicated to the rice genome research.

Question 49

Features:

Answer 49

• First genome crop to be completely sequenced.
• Arabidopsis is the experiment plant for the rice genome
• ## Rice was chosen because: It is from the grass family, it is co-linear with maize, wheat and barley and it has a small genome with greater diversity)

430 Mbp