OBJECTIVES OF CHROMOSOME AND GENE LINKAGE

Multiple Choice Questions MCQs

Four options are given at the end of each statement. You should encircle one option from them.

Which of the followings is linker protein?

(a) H1                           (b) H2A,                      (c) I-12B                     (d) H3
Which of the following proteins is absent is in nucleosome?

(a) Fl1                           (b) H2A,                     (c) H2B                    (d) Birds

XO system is found in:

(a) man           (b) Earthworm                         (c) Protenor             (d) Birds

ZW system is found in:

(a) man           (b) Earthworm                         (c) Protenor             (d) Birds

XY system is found in:

(a) man           (b) Earthworm                         (c) Protenor             (d) Birds

2n —0 is:

(a) Nullisomics             (b) Tertrasomics           (c) Monosomic            (d) Trisomic

2n + 1 is:

(a) Nullisomics             (b) Tertrasomics           (c) Monosomic            (d) Trisomic

2n + 2 is:

(a) Nullisomics             (b) Tertrasomics           (c) Monosomic            (d) Trisomic

A :

1. a) 2. (a) 3. (c) 4. (d) 5. (a) 6. (a) 7. (d) 8. (c)*

Fl I in the blanks

  1. The fifth histone H1 is called the_______________ protein
  2. The active portions of chromosomes are called ____________ regions.
  3. Chromosomes that are represented differently in females and males and function in sex determination are called____________ chromosomes.
  4. Chromosomes that are alike and not involved in determining sex are called____________ .
  5. The XY system in birds and butterfly is called _________________ system.
    1. The change of sequence of nucleotides is called _______________ mutation.
    2. If a chromosome is missing the aneuploidy is _____________

    8.   If a set of chromosome is missing the aneuploidy is _____________.
    Ans:1. nker                                   2. euchromatic                      3. sex

    4. a tosomes                         5. ZW                                      6. point

    7. onosomic                          8. nullisomics

Short Questions

  1. What is chromatin?

An : The highly dispersed state of .chromosomes is called chromatin. The chromosome remains in chromatin state during most of the life cycle of cell. Therefore, the genes actively participate in the formation of protein.

  1. What is Chromosome?

Ans: The highly folded form during division of cell is called chromosomes. This condensed state distributes chromosomes equally between newly formed cells.

  1. Name different types of histone proteins. Ans: H1, H2A, H2E3, H3, H4
  2. What is linker protein?

Ans: T.he fifth histone H1 is called the linker protein. It is not needed to form the nucleosome. Rather it fixes the DNA with nucleosomes.

  1. What is heterochromatic region?

Ans: These are inactive portions of chromosomes. They show a banding pattern with certain stains. So they are called heterochromatin. The DNA of heterochromatin is not transcribed.

  1. What are euchromatic region?

Ans: The active portions of chromosames are called euchromatic regions.

  1. Differentiate between sex chromosomes and autosomes.

Ans: Chromosomes that are represented differently in females and males and function in sex determination are called sex chromosomes. Chromosomes that are alike and not involved in determining sex are called autosomes.

  1. What is XO system?

Ans: The system of sex determination in Protenor is called the XO system. It involves only one kind of chromosome. So it is the simplest system of sex determination.

  1. What is ZW system?

Ans: The XY system in birds and butterfly is called ZW system. In this case the male is XX and female is XY.

       10.   Give effects of mutation.


----------------------------


----------------------------

Ans: Some mutations are unnoticed. Some are beneficial. But mutations disrupt the structure of proteins. The evolutions of these proteins occur as result of evolution of million of years. Therefore, the results of mutations are always negative.

         11.    What is aneuploidy? How is it caused?

Ans: The random abnormal number of chromosomes in the animals is called as aneuploidy. Aneuploidy is mostly caused by an occasional accident, called a nondisjunction.

           12.    What is polyploidy?

Ans: A condition in which the organisms have more than two complete sets of chromosomes is called polyploidy.

             13.    Give comparison of aneuploidy and polyploidy.

Ans: Polyploids are more normal in appearance than aneuploids. One extra (or missing) chromosome disrupts genetic balance in aneuploids.

8> Chromosome and gene linkage 161  
 
True/ False            (For Punjab University only)

N arks are True or False statement. Give correct statement if false

Statement

  1. The highly dispersed state of chromosomes is called chromatin.
  2. The highly folded form during division of cell is called chromatin.
  3. Four types of Histone protein form a core particle called nucleosome
  4. The fifth histone H1 is called the nucleosome.
  5. Chromosomes that are alike and not involved in determining sex are called
  6. The genes present on the same chromosomes are called linked gene.
  7. Mutant flies have gray bodies and normal wings.
  8. Linked genes are located on the same chromosomes. So they do not assort independently.

9..The change of sequence of nucleotides is called point mutation.

Ans:

Statement T/F Correct Statement
  1. The highly dispersed state of
    chromosomes is called chromatin.
T  
  1. The highly folded form during division
    of cell is called chromatin.
F The highly folded form during division of cell is called chromosomes.
  1. Four types of Histone protein form a
    core particle called nucleosome.
T _
  1. The fifth histone H1 is called the nucleosome.
F The fifth histone Hi is called the linker protein.
  1. Chromosomes that are alike and not involved in determining sex are called autosomes.
T  
  1. The genes present on the same chromosomes are called linked gene.
T  
  1. Mutant flies have gray bodies and normal wings.
F Wild-type flies have gray bodies and normal wings.
  1. Linked genes are located on the same chromosomes. So they do not assort independently.
T  
  1. The change of sequence of lucleotidesis called point mutation.
T  

 

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