Tag: botany

Questions Related to botany

Chromosome carrying centromeres at one end is :

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

  1. Metacentric

  2. Submetacentric

  3. Acrocentric

  4. Telecentric

Show answer
Correct Option: D
Explanation:

A chromosome consists of two identical halves, the chomatids which are held together at one point. This point is known as centromere. The centromere appears as a narrow region called primary constriction, of the chromosome. On the sides of centromere, disc shaped structures are present known as kinetochores.
Depending on the position of centromere, chromosomes can be classified into four types:

  • Metacentric
  • Sub-metacentric
  • Acrocentric
  • Telocentric
Chromosome carrying centromeres at one end is called telocentric. It is also known as terminal chromosome because centromere is present at the terminal end. Thus, this chromosome appears to have a single arm.

Human chromosomes have been grouped on the basis of size and centromere into ____ types

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

  1. $5$

  2. $6$

  3. $7$

  4. $10$

Show answer
Correct Option: C
Explanation:

We group chromosomes into 7 groups, based on their size (how long they are), and the position of their centromeres (the narrow part that separates the two arms from one another). Some chromosomes have their centromeres at or near the middle, some have them somewhere between the middle and the end, and some have centrosomes at the very end of the chromosomes.


So, the correct answer is '7'.

A chromosome with centromere in the middle is

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

  1. Metacentric

  2. Telocentric

  3. Acrocentric

  4. Dicentric

Show answer
Correct Option: A
Explanation:
A. Metacentric chromosomes are X-shaped chromosomes and the centromere are present in the center so that the two arms are equal.
B. 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.
C.  An acrocentric chromosome is a  chromosome in which the centromere is located near to one end of the chromosome. 
D. A dicentric chromosome (abnormal centormere) is formed by the fusion of two chromosome segments thus, have two centromere.
So, the correct answer is 'Metacentric'.
Select the incorrect match from the following.
botany cell structure and organization membrane bound organelles cell: size and differentiation microscopy

  1. Terpenoids - Monoterpenes

  2. Lectins - Concanavalin A

  3. Toxins - Anthocyanins

  4. Drugs - Vinblastin

Show answer
Correct Option: C
Explanation:
 Some Secondary Metabolites Some Secondary Metabolites 
 Pigments  Carotenoids, anthocyanins, etc. 
 Alkaloids Morphine,Codeine ,etc. 
 Terpenoids Monoterpenes, Diterpenes, etc. 
 Essential oils Lemongrass oil,etc. 
 Toxins Abrin,Ricin 
Lectins  Concanavalin A 
 Drugs Vinblastin, Curumin, etc. 
 Polymeric substance  Rubber,Gums,Cellulose. 

So, the answer is 'Toxins - Anthocyanins'.

The chromosome in which centromere lies slightly away from the middle of the chromosome resulting into one shorter arm and one longer arm, is called as
botany nucleus and chromosome membrane bound organelles cell: size and differentiation microscopy

  1. Metacentric

  2. Submetacentric

  3. Acrocentric

  4. Telocentric

Show answer
Correct Option: B
Explanation:

In submetacentric type of chromosome, the centromere lies at some distance away from the midpoint, dividing the chromosomes into two unequal arms.

So, the correct answer is 'Submetacentric'

Nucleoprotein structures found at the end of chromosome are

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

  1. Centromere

  2. Telomeres

  3. Satellites

  4. Centrosomes

Show answer
Correct Option: B
Explanation:
  • Telomeres are essential nucleoprotein structures at the ends of eukaryotic chromosomes. They play several essential roles preserving genome stability and function, including distinguishing chromosome ends from DNA double-stranded breaks (DSBs) and maintenance of chromosome length.
  • The centromere is the point of attachment of the kinetochore, a structure to which the microtubules of the mitotic spindle become anchored.
  •  Satellite DNA consists of very large arrays of tandemly repeating, non-coding DNA. Satellite DNA is the main component of functional centromeres, and form the main structural constituent of heterochromatin.

So, the correct answer is 'Telomeres'.
Read the given statements.

(i) Centromere is present in the middle of the chromosome and forms two equal arms.
(ii) Chromosome has a terminal centromere.
(iii) Centromere lies close to the end of the chromosomes forming one extremely short and one very long arm.
(iv) Centromere lies slightly away from the middle of the longer arm.

Select the correct option as per the codes given above.
botany nucleus and chromosome membrane bound organelles cell: size and differentiation microscopy

  1. $Metacentric - (i), Submetacentric - (iv), Acrocentric - (iii), Telocentric - (ii)$

  2. $Metacentric - (i), Submetacentric - (ii), Acrocentric - (iii), Telocentric - (iv)$

  3. $Metacentric - (iv), Submetacentric - (i), Acrocentric - (iii), Telocentric - (ii)$

  4. $Metacentric - (iv), Submetacentric - (ii), Acrocentric - (iii), Telocentric - (i)$

Show answer
Correct Option: A
Explanation:

metacentric chromosome - has centromere in the center with arms of identical length on either sides (p=q) telocentric chromosome: has centromere at terminal end, one single arm, not distinguished as p and q sub metacentric chromosome: centromere slightly away from the centre, forming two unequal arms - p -shorter and q-longer acrocentric chromosome : centromere farther away from the center, closer to the terminal end. forms unequal arms, p-much shorter, q- quite longer. So, the correct answer is 'Metacentric−(i),Submetacentric−(iv),Acrocentric−(iii),Telocentric−(ii)'

The chromosome in which centromere lies slightly away from the middle of the chromosome resulting into one shorter arm and one longer arm, is called as _____________.

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

  1. Metacentric

  2. Submetacentric

  3. Acrocentric

  4. Telocentric

Show answer
Correct Option: B
Explanation:
In submetacentric type of chromosome, the centromere lies at some distance away from the midpoint, dividing the chromosomes into two unequal arms.
So, the correct answer is 'Submetacentric'

Select the incorrect match : 

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

  1. Submetacentric - L-shaped chromosomes chromosomes

  2. Allosomes - Sex chromosomes

  3. Lampbrush - Diplotene bivalents chromosomes

  4. Polytene - Oocytes of chromosomes amphibians

Show answer
Correct Option: D
Explanation:

Polytene chromosomes are large chromosomes which have thousands of DNA strands. They provide a high level of function in certain tissues such as salivary glands of Drosophila.

Lampbrush chromosomes are a special form of chromosome found in the growing oocytes of most animals, except mammals. Lampbrush chromosomes of amphibians, birds and insects are described best of all. Chromosomes transform into the lampbrush form during the diplotene stage of meiotic prophase I. They are bivalent.
So, the correct option is 'Polytene - Oocytes of chromosomes amphibians'.

Which of the following cellular structure contain pigments ?

botany cell structure and organization membrane bound organelles cell: size and differentiation microscopy

  1. ER, Golgibody, Chloroplast

  2. Vacuole, Chromoplast, Chloroplast

  3. Chloroplast, Chromoplast, Leucoplast

  4. Chloroplast, Nucleus, Mitochondria

Show answer
Correct Option: B
Explanation:

Chromoplast and chloroplast are types of plastics containing pigments while leucoplasts do not contain pigments. That is why leucoplasts are colourless. Also, many pigments (e.g., anthocyanins) are localized in the vacuoles of epidermal cells from flowers, leaves, and stems.


So, the correct option is 'Vacuole, Chromoplast, Chloroplast'.