Biology

Cell Cycle and Chromosomes

1,348 Questions

Explore a curated list of questions covering the cell cycle, mitosis, and meiosis. Topics include DNA replication, chromosomal structures, and genetic disorders. This material is essential for students preparing for biology and general science competitive exams.

Cell cycle eventsDNA replicationMeiosis processChromosomal structuresGenetic disorders

Cell Cycle and Chromosomes Questions

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

Chromatid is

  1. One half of chromosome

  2. Haploid chromosome

  3. Complete chromosome

  4. Duplicate chromosome
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation
1) A chromatid is one-half of two identical copies of a replicated chromosome. During cell division, the identical copies are joined together at centromere. Joined chromatids are known as sister chromatids. Once the joined sister chromatids separate from one another in anaphase of mitosis, each is known as a daughter chromosome.

2) In gamete cells, the cell contains half the number of chromosomes as body cells, are called Haploid chromosomes.

3) Body cells such as muscle,skinblood etc. These cells contains a complete set of chromosomes (46 in humans),are called Diploid or complete chromosomes.

So, the correct answer is 'One half of chromosome'.
Multiple choice botany the mitotic cell cycle chromosome and its structure chromosome nucleus and chromosome

The nuclear component that contains genes which are responsible for heredity or transfer of characteristics from parents to children is/are

  1. the Chromosomes

  2. the Cytoplasm

  3. the Nucleolus

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

The chromosomes are thread-like structures which can be seen enclosed in a cell nucleus. These chromosomes contain genes which are responsible for the transfer of characteristics from parents to the children.

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

Choose the correct statement.

  1. Genes are located in the chromosomes

  2. Cell is locked in the nucleus

  3. Chromosomes are located in the nucleolus

  4. Cell membrane surrounds the nucleus
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

The chromosomes are the condensed chromatin. They are made up of DNA and proteins Those sequences of DNA that code for proteins are called the genes. 

A. Genes are the segment of DNA that is located in the chromosome. The location of a gene on a chromosome is called the locus.
B. Nucleus is an organelle present inside the cell.
C. Nucleolus is the region on chromosomes that forms the ribosomal RNA.
D. Nuclear membrane surrounds the nucleus. Cell membrane surrounds the cell.
Hence, the correct answer is 'Genes are located in the chromosomes'

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

Chemical composition of chromosome : 

  1. DNA and lipids

  2. DNA and carbohydrates

  3. Proteins and lipids

  4. DNA and proteins
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

The chemical composition of a chromosome is DNA and proteins(histone). Because chromosome is a supercoiled structure made up by coiling of DNA on the proteins like histone

So the correct option is"DNA and Proteins".

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

Which of the following statements is incorrect?

  1. Every chromosomes essentially has a secondary constriction

  2. The interphase nucleus has a loose and indistinct network of nucleoprotein fibres called chromatin
  3. A single human cell has approximately $2.2$ metre long thread of DNA distributed among its forty six chromosomes

  4. Chromatin contains DNA and some basic proteins called histone, some non histone proteins and also RNA
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Not all chromosomes have a secondary constriction; only specific chromosomes (SAT-chromosomes) possess them. The other statements correctly describe chromatin, DNA length, and composition.

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

Chromosome consists of

  1. DNA only

  2. DNA and histone protein

  3. DNA, histone proteins and non-histones proteins

  4. DNA and non-histones protein
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Chromosomes are made up of DNA and protein. Histone and non-histones proteins are associated with chromosomal DNA. Histone participate as structural components and provide strength and stability and protect DNA from shearing and breakage while the non-histones act as functional or regulatory components either in activation or repression of genes.

So, the correct answer is option C.

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

Chromosomes are composed of

  1. DNA, RNA, histones, non-histones

  2. DNA and histones

  3. DNA and RNA

  4. DNA, RNA and histones
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Chromosomes are composed of DNA, RNA, histones, non-histones. A chromosome is a packaged and organized chromatin, a complex of macromolecules found in cells, consisting of DNA and protein. The functional segments of DNA are known as genes. The DNA-bound macromolecules are proteins, which serve to package the DNA and control its functions.

So, the correct answer is option A.

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

The non-sticky chromosomal ends are known as

  1. Chromatids

  2. Centromere

  3. Chromomere

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

The telomeres do not have any overhanging ends of nucleotides so it is known as non sticky chromosome ends called telomere. A telomere is a region of repetitive nucleotide sequences at each end of a chromatid, which protects the end of the chromosome from deterioration or from fusion with neighboring chromosomes. 

So, the correct answer is option D.

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

Bead like structure found on chromosome are called as

  1. Chromomeres

  2. Chromonemata

  3. Chromonema

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

A chromomere  is one of the serially aligned beads or granules of a eukaryotic chromosome, resulting from local coiling of a continuous DNA thread. It is visible on a chromosome during the prophase of meiosis and mitosis. The chromomeres are present during leptotene phase of prophase I during meiosis. During zygotene phase of prophase I, the chromomeres of homologs align with each other to form a homologous rough pairing. These chromomeres help provide a unique identity for each homologous pairs.

So, the correct answer is option A.

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

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.