Cell Division. 3.1 Cell Division Cell division occurs in all organisms, but does different things or...
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Transcript of Cell Division. 3.1 Cell Division Cell division occurs in all organisms, but does different things or...
Cell Division
3.1 Cell Division
Cell division occurs in all organisms, but does different things or functions.
Unicellular organisms reproduce through cell division.
Multicellular organisms use cell division to grow, develop, repair themselves, and reproduce.
Genetic Material
The genetic material of a cell contains information needed for the cell’s growth and other activities.
When a cell divides into two new cells, each cell receives a full set of genetic material.
The genetic material is contained in DNA molecules.
DNA DNA stands for deoxyribonucleic acid DNA is a molecule that contains information
for an organism’s growth and functions. James Watson and Francis Crick
discovered the shape of DNA and made a model of it in 1953.
They showed that DNA
Twists like a ladder or a
Double helix
DNA and Chromosomes
DNA is stored in the nucleus of a cell DNA is wrapped around proteins to be
made smaller or more compact in structures called chromosomes.
DNA is replicated or copied so each new cell gets a copy.
Chromosomes
Chromosomes consists of 2 chromatids held together by a centromere.
Humans have 46 chromosomes, 23 from mom and 23 from dad
Cell Division
Cell Division is involved in growth, development and repair.
Through cell division a single cell becomes 2, and then they divide into 4 cells and so on.
Even when a person, animal or plant stops growing cell division still occurs because old cells need replaced with new ones.
Cells don’t live forever Throat cells only last a few days
Cell Growth
A large organism (animal or plant) does not have bigger cells then a smaller organism, it simply has more cells.
Cells grow in size but there is a limit to how big they can grow.
If cells get to big they can’t function properly (do their jobs correctly)
Cell Development
A multicellular organism starts as a single cell and grows into a larger one through cell division.
But as an organism develops each cell specializes and takes on a specific job.
Blood cells, muscle cells etc. All cells have the same DNA and parts but
they perform a specific job.
Cell Repair
If you have ever had a cut or broken bone, your body has repaired itself through cell division.
As cells age and die, they need to be replaced. Some cells last a long time and others wear out quickly
Skin cells- age very quickly Brain cells- live very long and don’t get
replaced often
3.1 Question: ____is a molecule that contains the information for a cell to grow and develop and is stored in a nucleus. A. Chromosomes B. RNA C. DNA D. Ribosomes E. Water
3.1 Question: DNA is wrapped around proteins to be made into_____.
A. Nucleotides B. RNA C. DNA D. Ribosomes E. Chromosomes
3.1 Question: Cell Division helps multicellular animals to ______.
A. get smarter B. grow, develop, and get smarter C. grow, develop, and repair D. turn purple E. reproduce
3.2 Cell Cycle
Living things grow, reproduce, and die in a process called a life cycle.
Cells have life cycles too, called the cell cycle.
The cell cycle is the normal sequence of development and division of a cell.
Cell cycle has 2 phases Interphase and Mitosis (Cell Division)
3.2 Cell Cycle
Interphase is the part of the cell cycle during which a cell carries out its normal functions and it is NOT dividing.
Mitosis is the part of the cell cycle during which the nucleus divides.
Only eukaryotic cells go through mitosis. The purpose of mitosis is to move DNA and
other material in position for cell division. Cytokinesis- division of the cytoplasm and
all organelles
Interphase: normal activities
Mitosis- Division of the Nucleus
Cytokinesis- Division of cytoplasm and other organelles
3.2 Cell Division
Cell division produces two genetically identical cells- they have the same DNA
If a skin cell divides you then have 2 identical skin cells
Mitosis has 4 phases- Prophase, Metaphase, Anaphase, and Telophase
3.2 Prophase
The first phase of mitosis DNA condenses (becomes smaller) into
chromosomes The chromosomes become visible The membrane around the nucleus breaks
down
First
3.2 Metaphase
Second phase of mitosis Chromosomes line up in the middle of the
cell
3.2 Anaphase
Anaphase is the 3rd phase of Mitosis The chromosomes split and are pulled to
opposite sides of the cell.
3.2 Telophase
Telophase is the 4th phase in mitosis A new membrane forms around the
chromosomes to form a nucleus Chromosomes return to their threadlike form
Recap
Interphase- The cell is doing its daily functions or jobs
Mitosis- Nucleus is preparing for Division and there are 4 phases- prophase, metaphase, anaphase, and telophase
Cytokinesis- The cytoplasm divides resulting in 2 identical cells.
3.2 Question: ____is the part of the cell cycle during which the cell is not dividing and just carrying out its normal functions. A. Prophase B. Mitosis C. Cytokinesis D. Anaphase E. Interphase
3.2 Question: ____is the division of the cytoplasm at the end of mitosis. A. Prophase B. Mitosis C. Cytokinesis D. Interphase E. Anaphase
3.2 Question: ____ is the phase of mitosis where the chromosomes first appear. A. Metaphase B. Prophase C. Telophase D. Anaphase E. Interphase
3.2 Question: is the part of mitosis where a new nuclear membrane forms and chromosomes turn threadlike. A. Metaphase B. Prophase C. Telophase D. Anaphase E. Interphase
3.2 Question: This is the phase of mitosis where the chromosomes line up in the middle. A. Metaphase B. Prophase C. Telophase D. Anaphase E. Interphase
3.2 Question: This is the phase in mitosis where the chromosomes separate and get pulled to opposite sides of the cell. A. Metaphase B. Prophase C. Telophase D. Interphase E. Anaphase
3.3 Cell Division for Unicellular Organisms For unicellular organisms cell division
produces 2 new organisms. This form of reproduction is called asexual
reproduction. Asexual reproduction is where a parent
organism produces offspring that are genetically identical to the parent.
Asexual reproduction involves one parent
3.3 Types of Asexual Reproduction Binary Fission is a type of asexual
reproduction and occurs when the parent replicates it’s DNA and then splits in two.
Budding- is a process where an organism develops tiny outgrowths called buds which break off to form a new organism.
Regeneration- is a process in which missing body parts are replaced. (Starfish, some plants)
Binary Fission
Budding
Sexual Reproduction vs. Asexual Repro. Two parents involved Offspring’s genes are
combined from two parents
Reproduce more slowly
Advantages: increased genetic variation
Disadvantages: slower, more energy required, must find a mate
One parent organism Offspring’s genes are
identical to parents Reproduces quickly
Advantages: fast and easy
Disadvantage: not much genetic variation
3.3 Question: _____is where a parent organism produces offspring that are genetically identical to them. A. Binary Fission B. Sexual Reproduction C. Asexual Reproduction D. Regeneration E. Splitting in half
3.3 Question: _____occurs when the parent organism replicates its DNA and then splits in two. A. Binary Fission B. Sexual Reproduction C. Asexual Reproduction D. Regeneration E. Mitosis
3.3 Question: ____is the process in which body parts can be replaced.
A. Binary Fission B. Sexual Reproduction C. Asexual Reproduction D. Mitosis E. Regeneration
3.3 Question: ____takes longer but results in genetically different offspring. A. Binary Fission B. Sexual Reproduction C. Asexual Reproduction D. Regeneration E. Mitosis