M2: Chemical Basis of Heredity

Question 1

Characteristics of a Genetic Material

Answer 1

1. Replication
2. Storage of Information
3. Variation by Mutation

Question 2

Direct Proof that DNA is a Genetic Material

Answer 2

1. Avery-Macleod-McCarty Experiment
   - DNA causes a transformation in bacteria
2. Hershey-Chase Experiment
   - DNA directs the reproduction of viruses

Question 3

Indirect Proof that DNA is a Genetic Material

Answer 3

1. Griffith’s Transforming Principle
2. Recombinant DNA Technology
3. Phage DNA-mediated infection
4. DNA absorbance wavelength
5. DNA found on organelles

Question 4

Building blocks of DNA

Answer 4

2-deoxyribonucleotide

Question 5

Building blocks of RNA

Answer 5

ribonucleotide

Question 6

Bond between phosphate and pentose sugar

Answer 6

Phosphoester bond

Question 7

Bond between base and pentose sugar

Answer 7

n-glycosidic bond

Question 8

Difference between 2-deoxyribose and ribose

Answer 8

presence of -OH group in 2’ of pentose sugar in Ribose

Question 9

Pyrimidine

Answer 9

Single rings like Thymine, Uracil and Cytosine

Question 10

Purine

Answer 10

Double rings like Adenine and Guanine

Question 11

Bond between 2 nucleotide

Answer 11

Phosphodiester bond

Question 12

Basis of Watson and Crick DNA model

Answer 12

B DNA

Question 13

Suggested that DNA is similar to a helix

Answer 13

X-ray Diffraction Data

Question 14

Position of nitrogenous bases

Answer 14

Nitrogenous bases are planar, perpendicular to the axis, and stacked on one another

Question 15

Diameter of DNA

Answer 15

20 A or 2.0 nm

Question 16

Covalent bonds in DNA

Answer 16

bases and sugar (phosphodiester bond)

Question 17

Hydrophobic bond in DNA

Answer 17

Stacked base pairs

Question 18

Erwin Chargaff rule

Answer 18

A=T & C=G

Question 19

DNA that is prevalent under high-salt or dehydration conditions

Answer 19

A-DNA

Question 20

DNA with greater dehydration condition than A/B DNA

Answer 20

C-DNA

Question 21

DNA occurring in helices lacking in guanine

Answer 21

D & E DNA

Question 22

Artificially stretched DNA

Answer 22

P-DNA

Question 23

Small synthetics DNA oligonucleotide with G-C pairings

Answer 23

Z-DNA

Question 24

DNA organization in Eukaryotes

Answer 24

1. DNA double helix (2 nm)
2. Chromatin (11 nm)
3. Chromatin fibre (30 nm)
4. Extended Chromosome (300 nm)
5. Condensed Chromosome (700 nm)
6. Mitotic Chromosome (1400 nm)

*ideally, the measurements are familiarize

Question 25

First level of packaging | DNA unwinding around histones

Answer 25

Nucleosome

Question 26

Second level of packaging | six-fold compaction

Answer 26

Solenoid

Question 27

First to observed Polytene chromosomes

Answer 27

E.G. Balbiani

Question 28

Giant chromosomes formed during interphase found in fly larvaes, protozoans and plants

Answer 28

Polytene Chromosmes

Question 29

Linear series of alternating bands and interbands | Paired homologs

Answer 29

Bands in Polytene Chromosomes

Question 30

Visible manifestation of inidividual genes

Answer 30

Chromomeres

Question 31

Visible manifestations of high level transcription | localized unwinding ## Footnote `

Answer 31

Puffs in Polytene Chromosomes

Question 32

Resemble brushes that is observable in oocytes and spermatocyte | Occurs meiosis I at chismata

Answer 32

Lampbrush Chromosome

Question 33

Process of inducing reversible changes in chromatin structure

Answer 33

Chromatin Remodeling

Question 34

Opening of Chromatin

Answer 34

Histone Modification

Question 35

Gene activation | Requires histone acetyltransferase

Answer 35

Acetylation

Question 36

Gene repression | Requires methyltransferase

Answer 36

Methylation

Question 37

Gene activation, cell cycle arrest, apoptosis, and damage repair | Requires kinase

Answer 37

Phosphorylation

Question 38

DNA Organization in Bacteria

Answer 38

* Supercoiling * Short surface area * Devoid of Associated proteins | * May also include functionally inert after packaging

Question 39

DNA structuring protein influence DNA compaction such as bridging, wrapping, and bending

Answer 39

Nucleoid-Associated Protein | Alternatives of Histone in Bacteria and Viruses

Question 40

DNA Organization in Virus

Answer 40

* Supercoiling * Active when released into a host cell | *Functionally inert as well after packaging

Question 41

Prone to mutation

Answer 41

RNA virus