free download Chromosome and DNA Cha 20 (0bj)

 Chromosome and DNA Ch 20 (0bj)

Q 1: Encircle the correct answer. (17)

1. Interphase nucleus contains:

a) chromatin   b) chromosomes      c) Microtubules     d) Spindles

2. More than 500 pairs of chromosomes are found in some:

a) Mosquitoes    b) Honey bees    c) Ferns     d) Sugar cane species

3. The particular array of chromosomes that an individual possesses is called its:

a) Karyotype     b) Primary constriction    c) Kinetochore  

 d) Secondary constriction

4. A typical human chromosome contains about -------- nucleotides in its DNA:

a) 100 million   b) 200 million   c) 140 million   d) 240 million

5. Histone proteins combine with DNA to from a complex:

a) Nucleosome    b) Kinetochore   c) chromatin  d) Centromere

6. Highly condensed portions of chromatin are called:

a) Euchromatin    b) Heterochromatin    c) chromatin   d) chromatids

7. Who did proposed the chromosomal theory of inheritance:

a)Karl Correns      b) alter Sutton       c) T.H.Morgan    d) F. Griffth

8. A.  Hershy and Chase performed experiments on bacterophage:

a) T₂-phage        b) T₃ -phage      c) T₄-phage      d) λ-phage

9. Repeating units of DNA are  called:

a) Histones      b) Nucleosides     c) Nucleotides     d) Amino acids         

10. Base pairs of DNA molecule are planar and stack------ apart:

a) 0.2nm     b) 2nm      c) 0.34 nm      d) 34nm

11. Meselson and Stahl grew bacteria in a medium containing heavy isotope of:

a) Sulphur      b) Nitrogen      c) Phosphrous     d) Oxygen

12. It is a relatively small enzyme which plays a supporting role in DNA replication:

a) DNA polymerase I      b) DNA polymerase II

c) DNA polymerase III     d) RNA polymerase I

13. RNA primer is a consequence of about --------RNA nucleotides:

a) 10     b) 20     c) 30     d) 40

14. Patients produce urine that contain homogentisic acid:

a) Phenylketonuria     b) Alkaptonuria       c) Sickle cell anemia  

d) Down’s syndrone

15. A sequence of nucleotides that determines the amino acid sequence of protein is called:

    a) Codon      b) Anticodon       c) Gene      d) Genotype

16. Enzymes are responsible for assembly of :

a) Nucleic acid     b) Protein     c) Carbohydrates     d) All of these

17. Which one is not appropriate to point mutation:

a)      Mutational changes affecting message it self

b)      Producing alterations in sequence of DNA nucleotides

c)      Due to spontaneous pairing errors

d)     Down’s syndrome is an example
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