Asexual Reproduction and Mitosis Complete Notes€¦ · material of the parent organism (clone). •Some organisms with eukaryotic cells asexually reproduce by cell division (division

Asexual Reproduction and Mitosis Complete Notes

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Cell Reproduction1. Asexual Reproduction, Cell Division and

Mitosis2. Sexual Reproduction and Meiosis

3. DNA

https://www.thoughtco.com/mitosisandcelldivisionquiz4078417


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Asexual Reproduction• In order for an organism to produce other organisms of its kind, it must

undergo reproduction.• In asexual reproduction, a new organism (or organisms) is produced from just

one organism.• The new organism will have hereditary material identical to the hereditary

material of the parent organism (clone). • Some organisms with eukaryotic cells asexually reproduce by cell division

(division of the nucleus known as mitosis).> Sweet potato in a jar of water. All the stems, leaves, and roots that grow

from the sweet potato have been produced by cell division and have the same hereditary material.


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Asexual Reproduction• Fission

> Some organisms, like bacteria, do not have a nucleus so they cannot use mitosis to reproduce.

> Instead bacteria reproduce asexually by fission.– This is the simplest form of reproduction.

> During fission, the cell without the nucleus simply copies the genetic material and then divides into two identical organisms.


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Asexual Reproduction• Budding

> Some organisms reproduce by growing from the body of the parent organism.

> Hydra reproduce in this manner.> Budding is a type of asexual reproduction made possible because of cell

division (mitosis).> When a bud on the adult becomes large enough, it breaks away to live on its

own.• Regeneration

> Some organisms can re-grow damaged or lost body parts.> Regeneration is the process that uses cell division to re-grow a body part.> Sponges, planaria, starfish can regenerate to reproduce. They break into

pieces and a whole new organism will grow from each piece.

Hydra budding

Starfish regenerating


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So What is Cell Division?


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Cell Division• Many organisms begin as a single cell. How does that single cell grow? That cell

divides into two, two become four, four become eight, and so on.• Many-celled organisms (you) grow because cell division makes more cells.• Cells in your body wear out and are replaced every day.• In a matter of a few seconds, bone marrow produces about 6 million red blood

cells!• One-celled organisms use cell division to reproduce.• However, it is a more complicated process than just dividing a cell in half.

One-celled amoeba


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The Cell Cycle• All living things have a life cycle. A cell has a life cycle too.• Length of the Cycle

> A series of events that takes place from one cell division event to the next.> The time it takes to complete a cell cycle varies.

– 19 hours for bean plants– Cells in animal embryos take less than 20 min

> Cells in humans that are needed for repair, growth, or replacement constantly repeat the cycle.

**Animal Cell


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Interphase ("Enter")• Most of the life of Eukaryotic cells ( cells with a nucleus) is spent in a period

of growth and development called interphase.• There are cells in your body that no longer divide, like nerve and muscle

cells, so they are always in interphase. They just grow and develop.• Cells that actively divide, or will continue with further phases, copy the

hereditary material (DNA) and prepare for cell division during interphase.> Skin cells for example

• Why does the hereditary material need to be copied?> Think of a script needing to be copied for a play.> Before a cell divides, a copy of the hereditary material must be made so

that each of the two new cells will get a complete copy.• After interphase, the process of cell division begins.• Think of interphase like " entering into the phases of cell division".

Nerve and muscle cells always here

Interphase


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Mitosis• Mitosis is the division of body cells. This is a type of asexual reproduction.

> Mitosis = "My Toe sis"• Mitosis is the process in which the nucleus divides to form two identical nuclei.

> The new nuclei are identical to each other and the original (parent) nucleus.• Mitosis has a series of phases, or steps. There are 4 phases of mitosis.

> You will not be responsible for knowing the exact phases of mitosis, but you will need to recognize what generally happens.

https://www.khanacademy.org/science/biology/cellularmolecularbiology/mitosis/a/phasesofmitosis


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Mitosis• Chromosomes play an important role in cell

division.• A chromosome is a structure in the nucleus

that contains hereditary material (DNA).• Interphase (entering): Cell's chromosomes

duplicate. Why is this so important? • This is the step before cell division.• Mitosis (cell division) begins:

1. After the chromosomes duplicate the cell starts to elongate.

2. The cell pinches in the middle and becomes two identical cells (called daughter cells).

3. A complete set of chromosomes is in each new cell.

• Two new, identical cells are created at the end of mitosis. These two cells are also identical to the original cell.

• These two cells then begin the period of growth, or interphase, again.

(center)

DNA


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Summary of Mitosis


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Results of Mitosis• IMPORTANT!

1. Mitosis is the division of the nucleus. 2. Mitosis creates two new nuclei that are identical to each other and the

original nucleus• After mitosis, each new nucleus has the same number and type of chromosomes.• Your body cells have 46 chromosomes (23 pairs).• You began as a single cell with 46 chromosomes.• Each of your body cells has a copy of the same hereditary material.• However, all of your cells use different parts of the same hereditary material to

become different types of cells.> Just like actors in a play learn different lines for their different parts.

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Asexual Reproduction and Mitosis Complete Notes€¦ · material of the parent organism (clone). •Some organisms with eukaryotic cells asexually reproduce by cell division (division