Crossing is an enzyme-mediated process. The enzyme is:

(1) DNA ligase      

(2) Recombinase  

(3) RNAase           

(4) DNAase

Match Column-I with Column-II:
Column-I                                                                               Column-II
I. Chromosomes are moved to spindle equator                        A. Pachytene
II. Centromere splits and chromatids apart                               B. Zygotene
III. Pairing between homologous chromosomes takes place    C. Anaphase
IV. Crossing between homologous chromosomes                    D. Metaphase

(1) I-A, II-B, III-C, IV-D                               

(2) I-B, II-C, III-D, IV-A

(3) I-D, II-C, III-B, IV-A                               

(4) I-C, II-A, III-D, IV-B

Which event is not associated with prophase I?

(a) Synizesis                   (b) Synapsis                   (c) Segregation     (d) Terminalization

A cell cycle includes:

1. Interphase + M-phase / divisional phase

2. Prophase + Metaphase + Anaphase + Telophase

3. G₁ + S + G₂ – phase

4. Karyokinesis + Cytokinesis

Interphase:
(1) Includes karyokinesis and cytokinesis
(2) Some time called resting phase, is the preparatory phase for division in which cell undergoes growth and DNA replication in an order
(3) Is the shortest phase in which biomolecules are synthesised very fast
(4) Includes 5% duration of the cell cycle

Which one is correct for G₀ stage?

1. All are correct                         
2. I, II and III are correct
3. I and II are correct                       
4. I and IV are correct

At metaphase of mitosis, each chromosome consists of _______ chromatid(s) _______ centromere(s) ________ kinetochore(s) and _______ molecules of DNA:

(1) 2, 1, 2, 2        

(2) 2, 2, 2, 2       

(3) 2, 1, 1, 1                  

(4) 2, 1, 2, 1

In prophase mitosis, which one of the following events occurs in animal cells but not in plant cells?

(1) Centrioles migrate to opposite sides of the nucleus

(2) Homologous chromosomes do not associate

(3) The nuclear envelope (membrane) breaks down

(4) Nucleoli disappear

Synaptonemal complex is more conspicious at:

(1) Zygotene        

(2) Pachytene      

(3) Diplotene         

(4) Leptotene

Cellular structures which disappear during late prophase and reappear during telophase are:

(1) Mitochondria and spindle fibres   

(2) Plasma membrane

(3) Nuclear membrane and nucleolus 

(4) Plastid