Name the process by which an amoeba reproduces. Draw the various stages of its reproduction in a proper sequence. OR A student is viewing under a microscope a permanent slide showing various stages of asexual reproduction by budding in yeast. Draw diagrams of what he observes. (in proper sequence)

Q: Name the process by which an amoeba reproduces. Draw the various stages of its reproduction in a proper sequence. OR A student is viewing under a microscope a permanent slide showing various stages of asexual reproduction by budding in yeast. Draw diagrams of what he observes. (in proper sequence)

### Reproduction in Amoeba Amoeba reproduces asexually through the process of **Binary Fission**. #### **Stages of Binary Fission in Amoeba:** 1. **Parent Cell:** The mature Amoeba cell prepares for division. 2. **Karyokinesis (Nuclear Division):** The nucleus begins to elongate and constrict in the middle. 3. **Cytokinesis (Cytoplasmic Division):** The cytoplasm starts to constrict along the plane of division, dividing the cell body. 4. **Daughter Cells:** The constriction deepens until the cell splits completely into two independent, identical daughter Amoebae. ```diagram {"xrange": [-1.08, 10.08], "yrange": [-1.0, 1.0], "lines": [{"from": [0.0, 0.0], "to": [3.0, 0.0], "label": ""}, {"from": [3.0, 0.0], "to": [6.0, 0.0], "label": ""}, {"from": [6.0, 0.0], "to": [9.0, 0.0], "label": ""}], "points": [{"x": 0.0, "y": 0.0, "label": "1. Parent Amoeba\n(Nucleus in center)"}, {"x": 3.0, "y": 0.0, "label": "2. Elongation of Nucleus\n(Karyokinesis starts)"}, {"x": 6.0, "y": 0.0, "label": "3. Cytoplasmic Constriction\n(Cytokinesis begins)"}, {"x": 9.0, "y": 0.0, "label": "4. Two Daughter Amoebae\n(Fully separated)"}]} ``` --- ### OR: Budding in Yeast If observing asexual reproduction in **Yeast**, the process is called **Budding**. #### **Stages of Budding in Yeast:** 1. **Parent Yeast Cell:** A mature unicellular yeast cell. 2. **Bud Initiation:** A small protuberance or outgrowth (bud) appears on the parent cell body. 3. **Nuclear Division:** The nucleus of the parent cell divides, and one daughter nucleus migrates into the growing bud. 4. **Bud Separation / Chain Formation:** The bud matures, constricts at the base, and may either detach to form a new individual or remain attached to form a chain of buds.

How do Organisms Reproduce?

Binary Fission in Amoeba and Budding in Yeast

Official Answer

Reproduction in Amoeba

Amoeba reproduces asexually through the process of Binary Fission.

#### Stages of Binary Fission in Amoeba:

Parent Cell: The mature Amoeba cell prepares for division.
Karyokinesis (Nuclear Division): The nucleus begins to elongate and constrict in the middle.
Cytokinesis (Cytoplasmic Division): The cytoplasm starts to constrict along the plane of division, dividing the cell body.
Daughter Cells: The constriction deepens until the cell splits completely into two independent, identical daughter Amoebae.

OR: Budding in Yeast

If observing asexual reproduction in Yeast, the process is called Budding.

#### Stages of Budding in Yeast:

Parent Yeast Cell: A mature unicellular yeast cell.
Bud Initiation: A small protuberance or outgrowth (bud) appears on the parent cell body.
Nuclear Division: The nucleus of the parent cell divides, and one daughter nucleus migrates into the growing bud.
Bud Separation / Chain Formation: The bud matures, constricts at the base, and may either detach to form a new individual or remain attached to form a chain of buds.

Binary FissionAmoebaBuddingYeastKaryokinesisCytokinesisDaughter cellsBud

Marking Scheme

10.5 marks
20.5 marks
30.5 marks
40.5 marks

Hint

For Amoeba, show the nucleus elongating first, followed by the constriction of the cell membrane. For Yeast, show a small outgrowth forming on the parent cell.

Quick Oral Answer

Amoeba reproduces by binary fission. First, its nucleus elongates and divides into two. Then, the cytoplasm constricts and splits, forming two identical daughter cells.

Analysis & Explanation

Binary fission in Amoeba is a simple mitotic division where karyokinesis (division of the nucleus) is followed by cytokinesis (division of the cytoplasm). Since Amoeba has no fixed shape, this splitting can occur in any plane. In contrast, budding in yeast is an asymmetric division where a small daughter cell (bud) is produced on a larger parent cell, which may remain attached to form a colony before eventually separating.

Common Mistakes

1Drawing cytoplasmic division before nuclear division. The nucleus must always divide first.
2Forgetting to label the nucleus, cytoplasm, and daughter cells in the diagrams.

Interesting Facts

Unlike Leishmania, which has a whip-like flagellum and divides only along a definite longitudinal plane, Amoeba can divide in any plane because of its irregular, dynamic body shape.

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Frequently Asked Questions

How many marks does this question carry in CBSE Class 10 Science 2018?

This question carries 2 marks in the CBSE Class 10 Science 2018 examination.

Which chapter does this question come from in Science?

This question is from the chapter "How do Organisms Reproduce?" in the CBSE Class 10 Science syllabus.

What topic does this question cover in Science?

This question covers the topic "Binary Fission in Amoeba and Budding in Yeast" from CBSE Class 10 Science.

What type of question is this in the CBSE Class 10 Science 2018 paper?

This is a Short Answer question from Section B in the CBSE Class 10 Science 2018 paper.