Tag: chromosome and its structure

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Multiple choice botany the mitotic cell cycle chromosome and its structure chromosome nucleus and chromosome

Exceptionally, large chromosome is

  1. Lampbrush chromosome

  2. Polytene chromosome

  3. Megachromosomes

  4. All of the above
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

All chromosomes mentioned are large chromosomes. These chromosomes are producing large amounts of RNA for the oocyte, and most of the genes present in the DNA loops are being actively expressed. Each lateral loop contains one or several transcription units with polarized RNP-matrix coating the DNA axis of the loop.The majority of the DNA, however, is not in loops but remains highly condensed in the chromomeres on the axis, where genes are generally not expressed. This is about lampbrush chromosomes, the polytene and mega chromosomes are also larger than the other normal chromosomes.

So, the correct answer is option D.

Multiple choice botany the mitotic cell cycle chromosome and its structure chromosome nucleus and chromosome

A thread like structure in the nucleus of a cell formed of DNA which carries the genes is

  1. DNA

  2. Genes

  3. Chromosomes

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

Deoxyribonucleic acid (DNA) is the information-carrying molecule found in all living organisms. In most animal, plant and fungal cells, DNA is stored in the nucleus coiled up in thread-like structures called chromosomes.

So, the correct answer is option C.

Multiple choice botany the mitotic cell cycle chromosome and its structure chromosome nucleus and chromosome

Nucleus contains ________ which are rod shaped structures.

  1. Cytoplasm

  2. Chromosomes

  3. Chromatin

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

Chromosomes are thread like structures located inside the nucleus of animal and plant cells. Each chromosome is made of deoxyribonucleic acid (DNA). Passed from parents to offspring, DNA contains the specific instructions that make each type of living creature unique.

Multiple choice botany the mitotic cell cycle chromosome and its structure chromosome nucleus and chromosome

Which chromosomes are called as supernumerary?

  1. B-chromosome

  2. Sex chromosome

  3. Double minutes chormosome

  4. Lampbrush chromosome
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

B chromosomes are called supernumerary or accessory chromosomes. It is because these chromosomes are not considered as essential for being normal. These are not found in every individual. During alloploids, it suppresses homologous pairing which reduces multiple pairing between homologous chromosomes in allopolyploids.  

So, the correct option is A.

Multiple choice botany the mitotic cell cycle chromosome and its structure chromosome nucleus and chromosome

Who used the word "chromosome"

  1. Huxley

  2. Flemming 1888

  3. Kollikar 1888

  4. Waldeyer 1888
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation
Johannsen coined the term phenotype and genotype and conducted his pure line experiment in genetics.
Waldeyer 1888 used the term chromosome to describe certain structures that form during the process of cell division.
Benda coined the term mitochondria to describe their tendency to form long chains.
Flemming coined the term chromatin and mitosis, and also described the threadlike structure in the cell nucleus that was later named chromosome.
So, the correct option is 'Waldeyer 1888'.
Multiple choice botany the mitotic cell cycle chromosome and its structure chromosome nucleus and chromosome

Swellings present over the chromosomes are

  1. Centromeres

  2. Centrosome

  3. Puffs

  4. Chromomeres
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation
The centromere is the specialized DNA sequence of a chromosome that links a pair of sister chromatids
During mitosis, spindle fibers attach to the centromere via the kinetochore.
Centromeres were first thought to be genetic loci that directs the behavior of chromosomes
So, the correct answer is 'Centromeres'
Multiple choice botany the mitotic cell cycle chromosome and its structure chromosome nucleus and chromosome

Kinetochore is 

  1. Granule within centromere

  2. Surface of centromere

  3. Constriction near chromosome end

  4. End of chromosome
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation
The centromere is the lighter staining region on the chromosome of a cell which appears as a constriction.
They are also known as a primary constriction or kinetochore.
The kinetochore is a proteinaceous structure that assembles at the surface of the centromere which forms the site for binding of spindle fibres during cell division.
So, the correct answer is 'Surface of centromere'.
Multiple choice botany the mitotic cell cycle chromosome and its structure chromosome nucleus and chromosome

Telomeres

  1. Initiate RNA synthesis

  2. Help chromatids to move towards poles

  3. Seal ends of chromosomes

  4. Identify correct members of homologous pairs of chromosomes.
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation
  • A telocentric chromosome is a chromosome in which the centromere is located at the terminal end of the chromosome and their shape is similar to the letter i.
  • These chromosomes have a repetitive nucleotide sequence at each end of chromosomes. 
  • It seals and protects each end of the chromosomes from deterioration or fusion with the neighbouring chromosomes during cell division.
  • So, the correct answer is 'Seal ends of chromosomes'.
Multiple choice botany the mitotic cell cycle chromosome and its structure chromosome nucleus and chromosome

A constriction on the chromosome is

  1. Centromere

  2. Centrosome

  3. Centriole

  4. Chromomere.
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation
  • The centromere is the lighter staining region on the chromosome of a cell which appears as a constriction.
  • They are also known as a primary constriction or kinetochore.
  • It is a specialized DNA sequence that links a pair of sister chromatids where the spindle fibres are attached during cell division.
  • It is responsible for the transfer of replicated chromosomes into the two daughter cells during the cell division.
  • So, the correct answer is 'Centromere'
Multiple choice botany the mitotic cell cycle chromosome and its structure chromosome nucleus and chromosome

Satellite means

  1. Terminal part of the chromosome beyond secondary constriction

  2. Terminal part of the chromosome beyond primary constriction

  3. Terminal part of chromosome beyond tertiary constriction

  4. None of the above
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation
  • Satellite chromosomes or SAT chromosomes are those chromosomes which have secondary constrictions other than a centromere.
  • The terminal end of the chromosome present beyond the secondary constriction is called satellite which is attached to the chromosome by a thin thread called chromatin.
  • So, the correct answer is 'Terminal part of the chromosome beyond the secondary constriction'.