Question

which of the following are differences between mitosis and meiosis 1? Choose all that apply

A)Crossing over occurs during meiosis 1 but not mitosis

B)DNA replication takes place prior to mitosis but not before meiosis

C)Sister chromatids separate in mitosis and homologs (homologous chromosomes) separate in meiosis 1

D)Only meiosis 1 results in daughter cells that contain identical genetic information

E)Miosis 1 results in two daughter cells, while mitosis results in four daughter cells

Answer 1

Cell division phases :-

Interphase - This is preparatory phase of cell division. In this phase DNA is replicated and other substances like protein which are required for cell division are synthesized.
This phase occurs before both meiosis and mitosis division.

Mitosis division :-
• This type of division occurs in somatic cells of our body.
• In this division one mother cell is divided into two identical daughter cells.
• There are four phases - prophase, metaphase, anaphase and telophase.
In prophase, chromosomes condense.
In metaphase, chromosomes arranged in middle of cell.
In anaphase, centromere of chromosome is splitted and sister chromatids separated.
In telophase, chromatids reaches opposite pole of cell and cytokinesis starts.

Meiosis division :-
• This division occurs during gamete formation.
This division completed in two cycles - meiosis 1st and meiosis 2nd.
• In prophase of meiosis 1st, crossing over between chromatids occurs.
• In anaphase of meiosis 1st, centromere doesn't split and homologous chromosomes separated. After this stage, chromosome number remains half in each daughter cells.
• After meiosis 1st, two daughter cells are formed and these cells haploid and genetically different from each other.
• Meiosis 2nd is similar to mitosis.
• Interphase occurs only before meiosis 1st and there is no interphase before meiosis 2nd.
• After all two cycles of meiosis, four haploid cells are formed.

Now in question,
(A) Correct.
Crossing over occurs only during prophase of meiosis 1, and not in mitosis.

(B) Incorrect.
• DNA replication takes place before both meiosis and mitosis during interphase.

(C) Correct.
• Sister chromosomes seperate during anaphase of mitosis by centromere splitting.
• Homologous chromosomes seperate during anaphase of meiosis 1.

(D) Incorrect.
Meiosis 1 results in two genetically different daughter cells because of crossing over in prophase.

(E) Incorrect.
• Both mitosis and meiosis 1 result into two daughter cells.
• Mitosis results into diploid daughter cells whereas meiosis 1 results into two haploid cells.