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 ## Footnote (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 ## Footnote 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