Tag: organization of life

Questions Related to organization of life

Cell wall is absent in

biology organization of life comparison of prokaryotic vs eukaryotic cells prokaryotic cell and eukaryotic cell types of cell

  1. Mycoplasma

  2. Gametes

  3. Animal cells

  4. All the above

Show answer
Correct Option: D
Explanation:
Cell wall is composed of cellulose and it is mostly prominent in plant cell. It provides structural frame work to the cell and provides strength and rigidity to the cell.
Mycoplasma lacks cell wall around its plasma membrane which makes it resistant towards common antibiotics such as penicillin or other beta-lactam antibiotics that target cell wall synthesis.
Gametes are the haploid cells which is lined by basal germinal epithelium.
Animal cell lacks the cell wall and starts with the plasma membrane.
So, the correct answer is option D.

Which is correct option amongst the following statements?
(a) Nuclear membrane, chloroplast, mitochondria, microtubules and pili are absent in prokaryotic cells.
(b) Nuclear membrane, chloroplast, mitochondria, microtubules and pili are present in eukaryotic cells
(c) Ribosomes are 70S in prokaryotic cells and mitochondria. They are 80 S in animal cells.

biology organization of life comparison of prokaryotic vs eukaryotic cells prokaryotic cell and eukaryotic cell types of cell

  1. a and b are wrong, c is correct

  2. a is correct, b and c are wrong

  3. a and b are correct, c is wrong

  4. a and c are correct, b is wrong

  5. a, b and c are wrong

Show answer
Correct Option: A
Explanation:
  • Pilus refers to a thin and rigid hair-like appendage that protrudes from the cell surface of bacteria (prokaryotic cell) and is responsible for bacterial conjugation.
  • They are absent in eukaryotic cells.
  • The ribosomes present in a bacteria and the cellular organelles (mitochondria and chloroplasts) are 70S type and those present in a eukaryotic cell (both plants and animals) are 80S type.
  • So, the correct answer is 'a and b are wrong, c is correct'.

Plant cell differs from animal cell by

biology organization of life comparison of prokaryotic vs eukaryotic cells prokaryotic cell and eukaryotic cell types of cell

  1. Presence of vacuoles

  2. Presence of cell wall and chloroplast

  3. Absence at cell wall

  4. Absence of chloroplast.

Show answer
Correct Option: B
Explanation:

Plant and animal cells have several differences and similarities. For example, animal cells do not have a cell wall or chloroplasts but plant cells do. Animal cells are mostly round and irregular in shape while plant cells have fixed, rectangular shapes.

Hence B is the correct option. 

Assertion:  Initiation step of protein synthesis in prokaryotes and eukaryotes has several differences.

Reason:  They both form mRNA - tRNA complex with smaller subunit of ribosome.

biology organization of life comparison of prokaryotic vs eukaryotic cells prokaryotic cell and eukaryotic cell types of cell

  1. If both the assertion and the reason are true and the reason is a correct explanation of the assertion

  2. If both the assertion and reason are true but the reason is not a correct explanation of the assertion

  3. If the assertion is true but the reason is false

  4. If both the assertion and reason are false

  5. If the assertion is false but reason is true

Show answer
Correct Option: B
Explanation:

The differences between initiation step of protein synthesis in eukaryotes and prokaryotes are : 

(i) In prokaryotes initiation factors are three - IF1, IF2 and IF3. Eukaryotes have at least ten initiation factors - eIF1, eIF2, elF3, eIF4A, eIF4B, eIF4C, eIF4D, eIF4F, eIF5 and eIF6. 
(ii) In eukaryotes, formylation of methionine does not take place. In prokaryotes tRNA is charged with formylated methionine.
 (iii) The larger subunit of ribosome combines with 40S - mRNA - tRNAMet (in case of prokaryotes, 30S) complex to form intact ribosome. It requires initiation factor IF1 in prokaryotes and factors eIF1, eIF4 (A, B, C) in eukaryotes.

In eukaryotic cell,

biology organization of life comparison of prokaryotic vs eukaryotic cells prokaryotic cell and eukaryotic cell types of cell

  1. A spindle apparatus is produced during nuclear division.

  2. A spindle apparatus is not formed during division.

  3. Gametes are not formed

  4. Ribosomes are of 70S type

Show answer
Correct Option: A
Explanation:
The spindle apparatus (or mitotic spindle) refers to the cytoskeletal structure of eukaryotic cells that forms during cell division to separate sister chromatids between daughter cells. It is referred to as the mitotic spindle during mitosis, a process that produces genetically identical daughter cells, or the meiotic spindle during meiosis, a process that produces gametes with half the number of chromosomes of the parent cell.

So, the correct answer is 'A'.

Which of the following statements is not true for Nostoc?

biology organization of life comparison of prokaryotic vs eukaryotic cells prokaryotic cell and eukaryotic cell types of cell

  1. It is prokaryotic

  2. It is autotrophic

  3. It is filamentous

  4. It is macroscopic

Show answer
Correct Option: D
Explanation:
Nostoc  is a filamentous blue green alga or cyanobacteria. It is prokaryotic and microscopic.
So, the correct answer is 'It is macroscopic'

Which of the given structures of prokaryotes, resemble in composition to that of eukaryotes?

biology organization of life comparison of prokaryotic vs eukaryotic cells prokaryotic cell and eukaryotic cell types of cell

  1. Cell wall

  2. Cell membrane

  3. Ribosomes

  4. Both (2) and (3)

Show answer
Correct Option: B
Explanation:
Both prokaryotic and eukaryotic cells have a cell membrane, a double layer of lipids that separates the cell interior from the outside environment. This double layer consists largely of specialized lipids called phospholipids.
Thus, the correct answer is 'Cell membrane.'

The division of the plant kingdom into prokaryota and eukaryota is based on the characters of 

biology organization of life comparison of prokaryotic vs eukaryotic cells prokaryotic cell and eukaryotic cell types of cell

  1. Nucleus only

  2. Chromosomes only

  3. Cell organelles only

  4. All of the above

Show answer
Correct Option: A
Explanation:

The primary distinction between a prokaryotic cell and a eukaryotic cell is based on the nucleus. Hence, a cell having a 'pro' or primitive nucleus is called as prokaryotic, where the word 'karyon' means nucleus. Similarly, the cells with the advanced or well-developed nucleus are called as eukaryotic, where the word 'karyon' means nucleus. A prokaryotic cell also lacks membrane-bound cell organelles like chloroplast, mitochondria, Golgi bodies. etc., which are a characteristic of eukaryotic cell.

Lowest number of chromosomes is found in

biology organization of life comparison of prokaryotic vs eukaryotic cells prokaryotic cell and eukaryotic cell types of cell

  1. Radiolaria

  2. Amoeba

  3. Ascaris meglocephala

  4. None of the  above

Show answer
Correct Option: C
Explanation:

Ascaris meglocephala (horse round worm ) has chromosome number 2n = 2. 

Amoeba has chromosome number 2n = 12. 
The maximum numbers of chromosomes is found in a protozoan (Radiolarian), where total number of chromosomes are 1600 i.e. 2n = 1600.

Statement I : All prokaryotes have a cell wall, eukaryotes do not.
Statement II : Prokaryotes have a true nucleus, eukaryotes have a primitive nucleus.

biology organization of life comparison of prokaryotic vs eukaryotic cells prokaryotic cell and eukaryotic cell types of cell

  1. Both statement I and statement II are true and statement II is the correct explanation of statement I.

  2. Both statement I and statement II are true but statement II is not the correct explanation of statement I.

  3. Statement I is true but statement II is false.

  4. Both statement I and statement II are false.

Show answer
Correct Option: D
Explanation:
Prokaryotes generally have a tough layer which helps to maintain the strength and rigidity of the cells known as the cell wall. All the prokaryotes do not possess cell walls such as Mycoplasma. Eukaryotes like animals lack cell walls it starts with plasma membrane while plants have a cell wall.
Prokaryotes have a primitive nucleus that lacks membrane while eukaryotes have a true nucleus that has a double membrane nucleus. Thus, the correct answer is option D.