Tag: the origin of cells and cell division

Questions Related to the origin of cells and cell division

Identify the wrong statement about meiosis.

  1. Pairing of homologous chromosomes

  2. Four haploid cells are formed

  3. At the end of meiosis number of chromosomes are reduced to half

  4. Two cycle of DNA replication occur


Correct Option: D
Explanation:

Meiosis is a specialized type of cell division that reduces the chromosome number by half, creating four haploid cells. In meiosis, DNA replication is followed by two rounds of cell division to produce four daughter cells, each with half the number of chromosomes as the original parent cell. The two meiotic divisions are known as Meiosis I and Meiosis II.

So, the correct option is 'two cycles of DNA replication occur'.

Which of the following statement is not true for meiosis?

  1. It is a process in which the chromosomes duplicate only once

  2. It is a process in which the cell divides twice

  3. The karyokinesis skips one of the phases compared to mitosis

  4. It results in the formation of four haploid cells


Correct Option: C
Explanation:

The stage of karyokinesis does not skip any phase in mitosis as compared to meiosis because the cell division phases are the same in meiosis and mitosis.

So, the correct option is 'The karyokinesis skips one of the phases compared to mitosis'.

The sequence of origin of life may be

  1. Inorganic materials $\rightarrow$ Organic materials $\rightarrow$ Colloidal aggregate $\rightarrow$ Eobiont $\rightarrow$ Cell

  2. Organic materials $\rightarrow$ Inorganice materials $\rightarrow$ Colloidal aggregate $\rightarrow$ Eobiont $\rightarrow$ Cell

  3. Inorganic materials $\rightarrow$ Organic materials $\rightarrow$ Eobiont $\rightarrow$ Cell $\rightarrow$ Collodial aggregate

  4. Organic materials $\rightarrow$ Inorganic materials $\rightarrow$ Eobiont $\rightarrow$ Cell $\rightarrow$ Colloidal aggregate


Correct Option: A
Explanation:
Scientists have proved that organic materials are formed from the inorganic materials. The organic matter along with water have formed colloidal aggregate which later resulted in Eobiont and then cells.
So, the correct option is 'Inorganic materials $\rightarrow$ Organic materials  $\rightarrow$ Colloidal aggregate  $\rightarrow$ Eobiont  $\rightarrow$ Cell'

The book "Origin of species" was written by

  1. Darwin

  2. Beagle

  3. Mendel

  4. None of the above


Correct Option: A
Explanation:

On the Origin of Species (more completely, On the Origin of Species by Means of Natural Selection or the Preservation of Favoured Races in the Struggle for Life) published on 24 November 1859, is a work of scientific literature by Charles Darwin which is considered to be the foundation of evolutionary biology.

So, the correct answer is "Darwin".

A novel species with double stranded genetic material consists of 5 bases namely P. Q. R. S. T. with percentages given below. 

P Q R S T
Percentage  22 28 22 12 16

Based on the above information, which ONE of the following infrences is NOT supported by the observation?

  1. S- base pairs with T, and Q base pairs with R

  2. S base pairs with Q,and T base pairs with Q

  3. P base pairs with R, and S base pairs with Q

  4. P base pairs with R, and T base pairs with Q


Correct Option: A
Explanation:

P and R have the same percentage hence they must bond with each other.

The total percentage of S and T is equal to the percentage of Q hence Q binds to both S and T.
So the correct answer is ' Sbase pairs with T, and Q base pairs with R'.

First life consisted of.

  1. Protovirus

  2. Provirus

  3. Bacteria

  4. Virus


Correct Option: A
Explanation:
According to protovirus theory, first life consists of protovirus. It was given by Temin in 1971. It explained that a region of DNA in a cell transcribed into RNA then the RNA is copied back into DNA which can become integrated in the genome either of the original cell or other cells in the body, or both. It can function like gene amplification and cellular differentiation.

So the correct answer is 'Protovirus'.

In the successive seral stages , the following takes place, except : 

  1. Change in the diversity of species of organisms

  2. Increase in the number of species

  3. Increase in the number of organisms

  4. Decrease in the total biomass


Correct Option: A

Species belonging to different time period are called?

  1. Syntype

  2. Paratype

  3. Lectotype

  4. Isotype


Correct Option: A

Reptiles like mammals originated in ______________.

  1. Jurassic

  2. Cretaseus

  3. Triassic

  4. Permian


Correct Option: C
Explanation:
Answer is option D i.e. "Triassic"
The Triassic Period was the first period of the Mesozoic Era and occurred between 251 million and 199 million years ago. During the Triassic period, mammal-like reptiles called therapsids co-existed with ancestors to dinosaurs, crocodiles, mammals, pterosaurs, turtles, frogs, and lizards.

Timeline of the era can be shortly explained as: 
  • Jurassic - 200 million to 145 million years ago - first birds, first mammals.
  • Cretaseus - 145 million to 66 million years ago - first flowering plant, extinction of dinosaurs.
  • Triassic Period - 251 million and 199 million years ago - mammal-like reptiles.
  • Permian period - 299 to 251 million years ago - Fern plants, amphibians, fish, and invertebrates.

Which is incorrect about protobionts in abiogenic origin of life ?

  1. They were partially isolated from surroundings

  2. They could maintain an internal environment

  3. They were able to reproduce

  4. They could separate combination of molecules


Correct Option: A