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 reproduction in angiospermic plants artificial vegetative propagation common modes of vegetative propagation vegetative propagation asexual modes of reproduction

In a grafted plant, stock has $48$ chromosomes while scion has $24$ chromosomes. The chromosome number for root cells and eggs are.

  1. $48$ and $24$
  2. $24$ and $24$
  3. $24$ and $12$
  4. $48$ and $12$
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

The stock is the plant part containing strong root system and sicon is the plant part which contains better fruit and fruit yield. In root cells, the chromosome number remains constant, reduced half in egg cell. So the chromosome number for root cells are 48 and eggs are 12.

So the correct option is '48 and 12'.

Multiple choice botany heredity: from parents to offsprings experiments of mendel mendel's law of inheritance works of mendel

Independent assortment is absent in case of

  1. Genes located on the same chromosome

  2. Genes located on homologous chromosomes

  3. Genes located on nonhomologous chromosomes

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

Independent assortment is segregation of factors for a trait independent of other factors during gamete formation followed by their random rearrangement in progeny thereby producing both parental and new combinations. The linkage is the tendency of closely placed genes on a chromosome to stay together during inheritance; it produces more parental combination and less/no new combinations of the gene. The linkage is indirectly proportional to the distance between genes; the less the distance between the genes, the more linkage frequency between them. Genes present together on a chromosome may show linkage, if they are close enough, and do not follow independent assortment. Genes present on homologous and nonhomologous chromosomes are too far apart from each other to show linkage. The correct answer is A.

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

During cell division, spindle fibers attach to which part of chromosomes?

  1. Primary constriction

  2. Secondary constriction

  3. Chromomere

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

During cell division, spindle fibers attach to primary constriction of the chromosomes. Spindle fibres are mainly composed of microtubules which contract and relax to align the chromosomes at a particular orientation.

So, the correct answer is option A.

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

Bead like thickened portions of leptotene chromosomes are 

  1. Centromeres

  2. Chromomeres

  3. Centrioles

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

Bead-like thickened portions of leptotene chromosomes is chromomeres. During the leptotene stage, those duplicated chromosomes each consisting of two sister chromatids condense from diffuse chromatin into long, thin strands that are more visible within the cytoplasm.

So, the correct answer is option B.

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

Apart from sex chromosome, which is the other type of chromosome?

  1. Autosome

  2. Cytosome

  3. Both A and B

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

Chromosomes in humans can be divided into two types, autosomes, and sex chromosome. The sex chromosomes carry the characters linked to a particular trait. The autosomes contain the rest of the genetic hereditary information. Human cells have 23 pairs of chromosomes (22 pairs of autosomes and one pair of sex chromosomes), giving a total of 46 per cell.

So, the correct answer is option A. 

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

.......... gives chromosome its characteristic shape.

  1. Centrosome

  2. Centromere

  3. Centriole

  4. P-arm
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation
A chromosome is composed of DNA and proteins. DNA are the hereditary units which mainly carries the information from one generation to the other. The functional segments of the DNA are known as genes. Proteins are mainly present as histones which form a complex structure known as a nucleosome.
Each chromosome has a point where sister chromatids attached and give shape to the chromosome, called as the centromere, which divides the chromosome into two sections, or arms. It can be used to describe the location of specific genes. 
So, the correct answer is option B.
Multiple choice botany the mitotic cell cycle chromosome and its structure chromosome nucleus and chromosome

By which chromosomes are made of?

  1. DNA and RNA

  2. DNA and proteins

  3. DNA only

  4. Proteins only
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 protein and a single molecule 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

Chromosomes contain information for inheritance of features from parents to next generation in the form of 

  1. DNA

  2. RNA

  3. Proteins

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

Chromosomes are composed of DNA and proteins. DNA molecules contain the information necessary for constructing and organizing the cells. Functional segments of DNA are called as genes. In a cell, which is not dividing, this DNA is present as part of a chromatin material. Whenever the cell is about to divide, the chromatin material gets organized into chromosomes and transferred  to the next generation.

So, the correct answer is option A.

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

Chromosome carry .......... which helps in the inheritance or transfer of characters from the parents to the offspring.

  1. Genes

  2. Enzymes

  3. RNA

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

The nucleus of a cell contains chromosomes, which carry genetic information in a long molecule called as DNA. Genes are regions of DNA that carry the code to control a particular cell activity or the production of a particular protein.

So, the correct answer is option A.

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

The sex chromosomes of plants were first discovered in

  1. Algae

  2. Fungi

  3. Pteridophyta

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

Sex determination method is well understood in animals but not in plants. Plants may be monoecious or dioecious but the mechanism of sex differentiation was not well understood. It now appears that at least higher or flowering plants may be having sex determination mechanism based on sex chromosomes like animals, as humans which have XX and XY system of sex determination.

So, the correct answer is option D.

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

Eukaryotic chromosomes always exist

  1. In pairs

  2. In association with mitochondria

  3. Singly

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

Let's take Human somatic cell as an example for the typical eukaryotic cell.

The Human somatic cell is diploid that means the chromosomes exists in double number. 
And these chromosomes in the eukaryotic cell are located in the nucleus and no where associated with mitochondria.
The human somatic cell has 23 pairs of chromosomes but there are 24 types of chromosomes because X and Y chromosomes which are called as sex chromosomes were structurally not similar. 
The remaining 22 types of chromosomes exists in pairs which are homologous (structurally relative) with their pairs.
Hence, all the chromosomes doesn't exist in pairs.
And during the cell division process the homologous chromosomes were separated to opposite poles and therefore doesn't always exists in pairs.
And they also don't exist always in single.