test

Question 1

What can the cell cycle be divided into?

Answer 1

1. Short Dividing or Mitotic Phase (M Phase)—1 hr
2. Long Non-Dividing or Interphase

Question 2

What can interphase be divided into?

Answer 2

G1, synthesis, and G2

Question 3

When and What happens during G1?

Answer 3

It happens between the end of m phase and at the begining of the s phase.
During G1 phase, cells differentiate & perform their specialized functions as part of the whole tissue.

Question 4

What happens during s phase?

Answer 4

Synthesis or S phase: (10-12 hours)
Nuclear DNA is replicated—-completed sometime before the onset of mitosis

Question 5

What happens during G2?

Answer 5

Second Gap or G2 phase: (Relatively short)
The interval between the end of “S” phase & the beginning of the “M” phase, is relatively short & is the period in which cells prepare for mitotic division.

Question 6

What are the two events that occur in cell division? What are the ways that karyokinesis can occur in?

Answer 6

Twoevents occur in cell division
1. Karyokinesis - division of nucleus
2.Cytokinesis - division of cytoplasm

Karyokinesis- nuclear division can occur in 2 ways​:

1. amitotic or direct division - in this, nuclear material is randomly distributed in resultant cells​(it occurs in pathologicalconditions​)
   2. indirectdivision
   Mitosis
   Meiosis

Question 7

What are the phases of mitosis?

Answer 7

prophase
prometaphase
metaphase
anaphase
telophase

Question 8

What happens during prophase?

Answer 8

Thechromosomes begin to coil,contract and condense (C, C, C)

mitoticspindle forms

astral raysform

Thespindleand two asters together constitute the achromatic figure or disasteror/(amphiaster)

Question 9

What happens during prometaphase?

Answer 9

Chromatidsbecome distinguishable (you are becoming a real pro now and you become distinguished)

The nucleoli disintegrate anddisappear (your fears disengrate bc your becoming a pro)

Thechromosomes are released in thecytoplasm (your out on the filed now, not only in the training room)

Thespindlemicrotubules invade the central region ofcell (you get closer to your goal)

Thechromosomes movefrom the center towards the equator of thespindle (your assembling your forces )

Question 10

What happens during metaphase?

Answer 10

46 double structured chromosomes line up along theequatorialplane

Thedoubled structure of chromosomes isclearly visible (bc they’re in the middle now, they’re in the line of sight)

The centromere in metaphase is also a double structure (bc your dedication is stronger than ever, so it is fortified)

Question 11

What happens during Anaphase?

Answer 11

chromosomes get seperated to the opposite poles

Cleavagefurrowforms at thisstage (bc the furrow is between the a and a Anaphase)

Question 12

what happens during telophase?

Answer 12

Chromosomes lengthen and uncoil (they’re telling (telo) their friends about everything that happened (فضفضة))

Nucleus and Nucleoli reappear reappear (The roof that was holding you back comes back again)

New centrioles are formed (you close your knifes)

Division of cytoplasm occurs (you discover yourself again)

Question 13

What happens to the dna and number of chromosomes during meisois 1?

Answer 13

During meiosis-I, the amount of DNA is halved to diploid amount and the chromosome number is also halved from diploid to haploid. i.e., 23 (double structured)

(bc meiosis-1, so only one of then is haploid)

Question 14

What happens to the dna and number of chromosomes during meisois 2?

Answer 14

During meiosis-II, the amount of DNA is again halved and becomes the haploid but
the number of chromosomes remain the
same i.e., haploid (23) (single structured)

(both are haploid now bc meiosis 2)

Question 15

What are the stages of prophase-I

Answer 15

1. Prophase-I - It is divided into five phases

L ——– Leptotene
Z——— Zygotene
P ——– Pachytene
D———Diplotene
D———Diakinesis
(LZPDD) ——— LET ZAFAR PROVE DOUBLE DIVISION

Question 16

What happens during the Leptotene stage?

Answer 16

Chromosomes initially thin, begin to shorten and thicken

Chromosome appear as thin individual threads (bc lipton tea has the string thing )
Chromosomes are attached by their one end to nuclear envelope (the string is attached to the square thing on the thread of lipton)
Chromosomes show characteristic beaded appearance throughout their length. (each bead is called as chromomere)
Aster are formed
Spindle is formed
Nucleolus is present
Nuclear envelope is present

Question 17

What happens during Zygotene stage (stage of pairing)?

Answer 17

The homologous chromosomes come close to one another and form pairs without the attaching at the centromere

(from the name, like zygote bc from the mother and father)

Question 18

ًWhat is the Pachytene stage

Answer 18

Chromatids become visible attached at centromere (bc they form a patch)

**Each chromosome pair consist of 4 chromatids forming a tetrad **

crossing over happens, (They take patches from each other)

Question 19

What happens during Diplotene stage

Answer 19

Homologous pairs start separating except where crossing over has occurred (bc they become di again they become 2 instead of 4)

Question 20

What happens during Diakinesis?

Answer 20

The chiasama move farther away (kinesis so they used kinetic energy to move)

Question 21

What happens in prometaphase 1?

Answer 21

same as mitosis

Question 22

METAPHASE-I

Answer 22

23 pairs of chromosomes align along the equator

The bodies attaching to spindle microtubules are not single chromosomes but the bivalents i.e., pairs

Question 23

What is the result of meiosis-I

Answer 23

Diploid amount of DNA
Haploid number of chromosomes i.e., 23 (each chromosome is a double structured)