UDEE 2224 GENETICSBACHELOR OF SCIENCE (HONS) BIOCHEMISTRY

YEAR 2 SEMESTER 1

NAME : SANMUGAPRIYA ELAMPARUTHI

STUDENT ID : 09ANB08398

LECTURER’S NAME : Mr. Kam

EXPERIMENT : 3

EXPERIMENT TITLE : Mitosis and Meiosis

Title: Mitosis and Meiosis

Objectives:

1. To determine the chronological order the main events of mitosis.

2. To demonstrate the process of mitosis by preparing a squash of onion root

tip.

3. To compare and contrast the mitotic event in metaphase between a normal onion

root tip and a colchicines-treated onion root tip.

4. To compare and contrast the mitotic process in plant and animal cells.

Results:

Activity 1: Characteristic of Mitosis

1) Prophase 2) Prophase 3) Prophase

4) Metaphase 5) Anaphase 6) Anaphase

7) Anaphase 8) Telophase

Activity 2: Mitosis in Onion Root Tip Squashes

Prophase

Metaphase

Anaphase

Activity 3: Mitosis in plants vs. Mitosis in Animals

Animal:

Fish blastodisc Ascaris male

Plant:

Telophase

Prophase

Anaphase

Metaphase

Onion Mitosis root tip Allium I.s.

Activity 4: Characteristic of Meiosis

Activity 5: Meiosis in Grasshopper Spermatogenesis

Anaphase

Early prophase

Metaphase

Metaphase I Leptonema

Activity 6: Meiosis in Flowering Plants

Lily Anther First Meiotic Division Lily Anther Pollen Tetrad

Lily Ovulary First Meiotic Division Lily Ovulary Second Meiotic Division

Metaphase I

Lily Ovulary Megasporocyte c.s. Lily Ovulary First-Four Nucleate Stage

Table 1: Differences between mitosis in animal and plant cells.

Plant cells Animal cells

During telophase plants cell gets a cell

phase

During telophase, animal cells gets a

cleavage furrow during separation

Plant cells do not have centrioles. Animal cells have centrioles that migrate to

the ends of the cell to create the web of

spindle fibers that the chromatids attach to.

The plant cells have to form the cell wall

between the new cells.

Animal cells go through cleavage

cytokinesis, which is division of the cell

membranes

Activity 8: Compare and contrast between mitosis and meiosis

Mitosis Meiosis

Compare

o The chromosome of the diploid mother cell (mitosis) and diploid meiocyte

(meiosis) have been duplicated, associated with DNA synthesis before mitosis

and meiosis begin.

o Both mitosis and meiosis involve Cytokinesis in which the cleavage furrow splits

the cell in to two (mitosis and meiosis I) and four (meiosis II).

Contrast

o Mitosis consists of a single step of

cell division which includes

Prophase, early Metaphase,

Metaphase, Anaphase, Telophase.

o Meiosis consists of a two steps of

cell division which include

Prophase I and II, Metaphase I and

II, Anaphase I and II, Telophase I

and II

o Two identical diploid daughter (2n)

cells are produced after cell division

of mitosis.

o Two identical diploid daughter cells

are produced after cell division of

meiosis I. However, four

nonidentical haploid (n) cells are

produced after the cell division of

meiosis II.

o The Prophase stage in the mitosis

does not divide into five stages.

o The Prophase I of the meiosis is

divided into five stages which are

Leptonema, Zygonema,

Pachynema, Diplonema and

Diakinesis.

o The chromosomes have been

replicated before during Interphase.

o The chromosomes do not replicate

before meiosis II.

o The metaphase of the mitosis is

divided into two stages which are

early Prophase and Prophase. Both

steps occur continuously.

o The metaphase of the meiosis is

divided into two stages which are

meiosis I and II. Both steps occur

from meiosis I then to meiosis II.

o No synapsis and crossing over

occur in the mitosis.

o Synapsis and crossing over or

exchange of genetic materials

occurs in the Diplonema and

Pachynema of the Prophase I

respectively.

o Prophase

i. Centrosome duplicates,

chromosomes begin to

o Prophase I

i. Leptonema replicated

chromosomes become visible.

condense and become

visible.

ii. Formation of the spindle

accompanied by

fragmentation of many

intracellular.

iii. The nucleolus begins to

disappear.

iv. The nuclear membrane

breaks up into many

vesicles

v. Microtubules are formed

within the cytoplasm invade

the nuclear space. Some

microtubules attach to the

kinetochores.

ii. Zygonema homologous

chromosomes pair.

iii. Pachynema homologous

chromosomes fully paired. Crossing

over occurs.

iv. Diplonema homologous

chromosomes begin to repel each

other. Chromatids become fully

visible. Chiasmata become visible.

v. Diakinesis chromosomes

continue to shorten and thicken.

Nucleolus and nucleus membrane

disappear and microtubules attach

to kinetochores.

o Prophase II

Chromosomes condense and move

to metaphase plate.

o Metaphase

i. The duplicated

chromosomes move to

positions midway between

the spindle poles.

ii. The sister chromatids of a

duplicated chromosomes is

connected to a different pole

via microtubules attached to

its kinetochores.

o Metaphase I

Assembly of spindle is completed.

Each chromosome pair aligns

across the metaphase plate of the

spindle.

o Metaphase II

Kinetochores attach to the spindle

fibers. Chromosomes line up on

metaphase plate.

o Anaphase

i. The sister chromatids of

duplicated chromosomes are

separated from each other.

ii. The separation is

accompanied by shortening

o Anaphase I

Homologous chromosome pairs

separate and migrate toward

opposite poles.

o Anaphase II

Sister chromatids separate and the

of the microtubules that

attached to the kinetochores

and by degrading material

that hold the sister

chromatids together.

iii. The separated sister

chromatids (chromosomes)

are pulled to opposite poles

of the cell. Then the poles

begin to move apart.

move to opposite poles as separate

chromosomes.

o Telophase

i. Decondensation of the

chromosome.

ii. The nuclear membrane

reforms.

iii. The restoration of the

internal organelles.

o Telophase I

Chromosomes (each with two sister

chromatids) complete migration to

the poles and new nuclear

membranes may form.

o Telophase II

Nuclear membrane forms around

chromosomes and chromosomes

uncoil and Nucleolus re-forms.

Conclusion:

There are four stages (prophase, metaphase, anaphase and telophase) that presents

in mitosis which produce identical offspring. The differences between animal cell

and plant cell identified and able to differentiate. Meiosis 1 and 2 involve in the

spermatogenesis of grasshopper. Flowering plants have distinct alternation of

generation. The formation of megasporogenesis and megagametophyte in Lilium

involve four megaspores which play major role in the formation of the eight-

nucleate female gametophyte.

References:

1) Klug, Cummings, Spencer. Concepts of Genetics (9th edition). Pearson

International Edition.