Tag: nucleus and chromosome

Quizzes (2) Questions (129)

Questions Related to nucleus and chromosome

Multiple choice botany nucleus and chromosome membrane bound organelles cell: size and differentiation microscopy

Which chromosome does not provide attachment site for spindle fibers?

  1. Acrocentric

  2. Metacentric

  3. Submeta centric

  4. Acentric
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation
A chromosome in which the centromere is located quite near one end of the chromosome is called the acrocentric chromosome. Humans normally have five pairs of acrocentric chromosomes. Down syndrome is caused by an extra acrocentric chromosome (chromosome21). The acrocentric chromosome does not provide the attachment site for spindle fibers because centromere is located quite near one end of the chromosome.
So, the correct answer is 'Acrocentric'.
Multiple choice botany nucleus and chromosome membrane bound organelles cell: size and differentiation microscopy

Centromere is required for 

  1. Transcription

  2. Crossing over

  3. Cytoplasmic cleavage

  4. Movement of chromosomes towards poles
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

The late prophase or metaphase chromosome has two similar threads or chromatids attached to each other by a narrow non stainable area called as centromere. The two parts of the chromatids on either side of centromere are called as arms. Centromeres bind to spindle fibres and help in movement of chromosomes to opposite poles.

Multiple choice botany nucleus and chromosome membrane bound organelles cell: size and differentiation microscopy

Kinetochore is the

  1. Fibrous granular structure within centromere.

  2. Protein disc near centromere

  3. Construction near chromosome end.

  4. End of chromosome.
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation
  • The kinetochore is a disc-shaped protein complex associated with the centromere of a chromosome during cell division, to which the microtubules of the spindle attach.
  • It forms on a chromatid during cell division.
  • Hence Kinetochore is the protein disc near the centromere.
  • So, the correct answer is 'Protein disc near centromere'.
Multiple choice botany nucleus and chromosome membrane bound organelles cell: size and differentiation microscopy

Which chromosome may lost during cell division?

  1. Giant chromosome

  2. Acentric chromosome

  3. Polycentric chromosome

  4. Telocentric chromosome
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Acentric chromosomes may be lost during cell division. An acentric fragment is a segment of a chromosome that lacks a centromere. Because the centromere is the point of attachment for the mitotic apparatus, acentric fragments are not evenly distributed to the daughter cells in cell division. As a result, one of the daughters will lack the acentric fragment. Lack of the acentric fragment in one of the daughter cells may have deleterious consequences, depending on the function of the DNA in this region of the chromosome

Multiple choice botany nucleus and chromosome membrane bound organelles cell: size and differentiation microscopy

If the centromere is sub-median and the two arms are unequal then the chromosome is called as

  1. Metacentric

  2. Submetacentric

  3. Acrocentric

  4. Telocentric
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation
The centromere is the part of a chromosome that links sister chromatids. During mitosis, spindle fibers attach to the centromere via the kinetochore. 
Having the centromere near the center but not in the middle, so that one arm is shorter than the other is the property of a submetacentric chromosome.
Multiple choice botany nucleus and chromosome membrane bound organelles cell: size and differentiation microscopy

Which type of chromosome will appear 'L' -shaped during anaphase?

  1. Telocentric

  2. Acrocentric

  3. Metacentric

  4. Submetacentric
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

'L' shaped chromosomes that appear during anaphase are sub-metacentric. According to the position of the centromere, the metacentric chromosomes are X shaped and due to the unequal length of the arms of the chromosomes, they become L shaped and are called sub-metacentric.

Multiple choice botany nucleus and chromosome membrane bound organelles cell: size and differentiation microscopy

Arm ratio in metacentric condition is

  1. 1:1

  2. 1:2

  3. 1:3

  4. 2:3
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

The arm ratio in metacentric condition is 1:1. These are X-shaped chromosomes, with the centromere in the middle, so that, the two arms of the chromosomes are almost equal. A chromosome is metacentric, if its two arms are roughly equal in length. In a normal human karyotype, two chromosomes are considered metacentric: chromosomes 1 and 3. In some cases, a metacentric chromosome is formed by balanced translocation: the fusion of two acrocentric chromosomes to form one metacentric chromosome.

Multiple choice botany nucleus and chromosome membrane bound organelles cell: size and differentiation microscopy

Chromosome with centromere at one end is

  1. Metacentric

  2. Submetacentric

  3. Telocentric

  4. Acrocentric
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Chromosome with centromere at one end is telocentric. A telocentric chromosome's centromere is located at the terminal end of the chromosome. Telomeres may extend from both ends of the chromosome. Humans do not possess telocentric chromosomes.

Multiple choice botany nucleus and chromosome membrane bound organelles cell: size and differentiation microscopy

Small chromosomes which do not produce any detectable phenotypic expression are termed as

  1. Heterochromatic chromosomes

  2. Supernumerary chromosomes

  3. Nonsense chromosomes

  4. Nucleoids
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

A chromosome present in addition to the normal chromosome complement is called as a supernumerary chromosome, also known as accessory chromosome. These chromosome does not produce any detectable phenotypic expression in an organism. These chromosomes are not essential for the life of a species, and are lacking in some (usually most) of the individuals. Thus a population would consist of individuals with 0, 1, 2, 3 (etc.) supernumeraries.

Multiple choice botany nucleus and chromosome membrane bound organelles cell: size and differentiation microscopy

A chromosome with centromere at one end is called as

  1. Telocentric

  2. Metacentric

  3. Apocentric

  4. None of the above
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

The rod-like chromosomes which have the centromere on the proximal end are known as the telocentric chromosomes. Humans do not possess telocentric chromosomes but they are found in other species such as mice. Thus, the correct answer is option A.