Tag: botany

Quizzes (264) Questions (5276)

Questions Related to botany

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

Choose the correct answers from the alternatives given :
The centromere or primary constriction of the chromosome contains rings of protein that are intimately associated with a spindle fibre. These rings are called

  1. asters

  2. secondary constrictions

  3. centrioles

  4. kinetochores
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation
  • The kinetochore is the region which is present in the center of the chromosome near the centromere or the primary constriction.
  • The spindle fibers which are formed from the centrioles are required to pulled the chromosome towards the poles of the dividing daughter cells.
  • The spindle fiber of the centrioles are attached to the kinetochore which is a protein ring or made up of protein which forms bonds with tubulin protein of the spindle fiber, so that the chromosomes can be pulled apart towards the poles. 
  • Therefore the answer option 'kinetochores' is correct.
Multiple choice botany the mitotic cell cycle chromosome and its structure chromosome nucleus and chromosome

Which is not a major function of the genetic material?

  1. Store information

  2. Catalyse chemical reactions

  3. Replicate itself

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

Enzymes are present inside cells for catalyzing chemical reactions. While genetic material is present inside the nucleus as storage of information for all the cellular activities in the form of genes. Genetic material replicates during cell division. It can also undergo mutation during replication. 

So, the correct option is 'Catalyse chemical reactions'.

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

Select the correct option:

Which of the following stains is not used for staining chromosomes?

  1. Basic Fuchsin

  2. Safranin

  3. Methylene green

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

Chromosomes are heavily coiled DNA, a DNA molecule is negatively charged and has to be therefore stained with basic dyes like Basic fuchsin, Methylene green and carmine.while safranin is used to stain cell walls of plants and bacteria (counter stain)

So, the correct answer is 'Safranin'

Multiple choice botany the mitotic cell cycle chromosome and its structure chromosome nucleus and chromosome
According to most recent studies, each chromosome consists of

  1. Single double helical DNA which is highly coiled and folded

  2. Variable number of DNA helices, depending upon the length of chromosome

  3. Many small DNA helices, which are joined by peptide linkages

  4. Small DNA helices, wrapped around each other like a rope
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

There is a single, long, double-stranded, linear DNA molecule in a chromosome. The DNA contains biological and genetic information. It is highly coiled and folded, however this packing varies during the cell cycle.

So, the correct answer is 'Single double-helical DNA which is highly coiled and folded'.

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

Mark the correct option w.r.t. chromosomes.

  1. mRNA + ribosomes

  2. mRNA + protein

  3. DNA + Protein

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

The nucleus of each cell, the DNA molecule is packaged into thread-like structures called chromosomes. Each chromosome is made up of DNA tightly coiled many times around proteins called histones that support its structure.

So, the correct option is 'DNA + protein.

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

which of the following is typically not found in normal somatic cells of human male?

  1. the entire genetic information possesed by the original zygote

  2. an inactivated X chromosome

  3. forty four autosomes

  4. a diploid nucleus

  5. A Y chromosomes
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

An inactivated X-chromosomes : female have XX chromosomes and male have XY chromosomes ,for balance Xlinked gene between male and female,one X chromosome undergo inactivated during the female embryo development this is termed as X chromosomes inactivation

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

Which of the following dyes is best suited for staining chromosomes ?

  1. Basic Fuchsin

  2. Safranin

  3. Methylene blue

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

(a) Basic Fuchsin-  It is a green crystalline dye. It includes staining of tissues sections.

(b) Safranin- It is used to stain gram-negative bacteria, mucin, etc.
(c) Methylene blue- It is used to examine DNA or RNA under the microscope.
(d) Carmine -  It is a type of stain used to stain chromosomes, nuclei etc.
So, the correct option is 'Carmine'.

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

Which of the following does not occur during condensation of chromosomes?

  1. Unfolding of protein molecules

  2. Coiling of DNA

  3. Dehydration

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

Chromosome condensation is the dramatic re-organization of the long thin chromatin strands into the compact short chromosomes that occur in mitosis and meiosis. Here, the unfolding of proteins takes place, the DNA coils, dehydration takes place. However, there is no addition of water molecule or hydration that takes place during condensation.

So, the correct answer is option D.

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

Structure which provide shape to chromosome is called as

  1. Telomere

  2. Satellite

  3. Centromere

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

Centromere provides structure to the cell. The sister chromatids are linked together at the centromere. During mitosis, spindle fibers attach to the centromere via kinetochore. Their physical role is to act as the site of assembly of the kinetochore, a highly complex multiprotein structure that is responsible for the actual events of chromosome segregation, i.e., binding microtubules and send signals to the cell cycle machinery.

So, the correct answer is option C.

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

Part of chromosome after secondary constriction is called as

  1. Chromomere

  2. Telomere

  3. Satellite

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

Chromosomes are the carrier of genetic information in form of DNA. The secondary constrictions are used as a point of identification of chromosomes. These are always constant in their positions and hence, can be used as markers that identify particular chromosomes. A satellite chromosome or SAT chromosome has a chromosome segment that is separated from the main body of the chromosome by such a secondary constriction.

So, the correct answer is option C.