Question

Activity Writing :-

Write an activity on the topic –


→ Binary fission in amoeba



Mention these in the activity :-

★ Objective of the activity
★ Materials required in the activity.
★ Theory
★ Procedure
★ Observation
★ Inference
★ Precaution​

Answer 1

[ Refer in the attachment ]

${\bf{ \bold{ \underline{ \pink{Objective \: of \: the \: activity : }}}}}$

To Study Binary fission in Amoeba.

${\bf{ \bold{ \underline{ \green{Material \: Required: }}}}}$

Permanent slides of amoeba showing binary fission, compound microscope.

${\bf{ \bold{ \underline{ \blue{Theory: }}}}}$

✫ Binary fission is a method of asexual reproduction spatially in protozoans. In binary fission, a living organism divides in two e.g. in Bacteria, Amoeba, Paramecium etc.

✫ During binary fission in Amoeba, the nucleus of an adult Amoeba divides amitotically into two nuclei. It is followed by the appearance of a constriction in the cell membrane. It gradually deepens and divides the cytoplasm into two parts. Thus, forming to daughter Amoeba.

${\bf{ \bold{ \underline{ \orange{Procedure: }}}}}$

• Put a few drops of the pond water on a clean glass slide.

• Cover the water drops carefully with the coverslip.

• Remove the excess water coming out of the slides of the coverslip with the help of a filter paper.

• Observe the slide under low magnification and then in high magnification.

${\bf{ \bold{ \underline{ \purple{Observation: }}}}}$

1. The body of amoeba elongates. The nucleus also elongates and becomes thinner in the middle.

2. Constriction appears even in the body of the amoeba corresponding to the thinner part of the nucleus.

3. The nucleus elongates more and more and ultimately divides into two.

4. Division of nucleus (Karyokinesis) is followed by the division of cytoplasm (cytokinesis) Constriction becomes deeper and deeper ultimately divides the body of the amoeba.

5. Thus two daughter amoeba are formed from a single parent and the parent's identity is lost.

${\bf{ \bold{ \underline{ \red{Inference: }}}}}$

➙ The slide shows the elongated body of the amoeba with a constriction in the middle. The nucleus is under the process of division, hence the given slide shows the binary fission in amoeba.

${\bf{ \bold{ \underline{ \green{Precaution: }}}}}$

1. The slide should be observed first in law magnification and then in high magnification.

2. Focus the slide first by using coarse adjuster and then focus the slide by using fine adjustment knob.

3. Always lower the lens of microscope very slowly and gradually, looking through eye piece.

______________________________

Answer 2

AIM

To study

binary fission in Amoeba, and

budding in yeast with the help of prepared slides.

MATERIALS REQUIRED

Compound microscope, permanent slides of binary fission in Amoeba and budding in yeast.

THEORY

Binary Fission – This is a type of asexual reproduction which takes place in Amoeba. In this type of reproduction, parent cell divides into two small, nearly equal sized identical daughter cells. The two daughter cells then grow into adult organism. In binary fission parental identity is lost.

Budding – This is also a type of asexual reproduction which is common in yeast. In this type of reproduction a small bud-like outgrowth develops at the parent cell. This bud enlarges in size. The nucleus also enlarges in size and divides to form two nuclei. Out of these two nuclei, one goes into developing bud. When the bud attains almost the same size as that of parent cell, a separating wall is laid down between the bud and parent cell. This bud may detach from the parent cell or may produce another bud over it.

PROCEDURE

Select the slide of binary fission in Amoeba and budding in yeast.

Set-up a compound microscope. While looking through the eye piece, adjust the mirror and diaphragm so that microscope is illuminated.

Now, place the slide on stage and focus at low power. Observe it.

Without removing the slide, now change the focus to high power. Observe it.

OBSERVATIONS

(a) Binary Fission in Amoeba

This is a type of asexual reproduction in which two daughter cells (or two individuals) are formed from a single parent.

Parent cell becomes elongated.

Nucleus divides first and then the cytoplasm divides.

At the point of fission, constriction appears and deepens to divide the cell into two daughter cells.

b) Budding in Yeast

In this type of asexual reproduction, a small protuberance or outgrowth arises from the parent body called bud.

Nucleus divides to form two daughter nuclei, of which one passes into the bud.

The bud now detaches from the parent body and grows independently as a new individual or may remain attached to parent body, forming chain of cells.

Parental identity is not lost.

RESULT

The slides show reproduction by binary fission in Amoeba and budding in yeast.

PRECAUTIONS

Always focus the slide, first at low power and then at high power.

While focussing at high power, do not use coarse adjustment of microscope. Only use fine adjustment.