Quick Write

1. Who do you most agree with? _____________2. Why do you agree with this student? ____________________________________________________________________________________________________________________________________________________

Vocabulary Throwback…

What does it mean when you have the PREFIX ‘A-”

Example: Abiotic?

So…

What do you think the word ASEXUAL means?

Asexual Reproduction

HEREDITY is the process by which parent organisms transfer their genetic information (DNA) to offspring.

Eukaryotic organisms (plant/animal) transfer genetic information (DNA) in the form of CHROMOSOMES (coiled DNA).

Most human cells contain 23 pairs or 46 chromosomes.

ASEXUAL reproduction - the production of genetically identical offspring from one parent using MITOTIC cell division.

What does Asexual Reproduction Result in?

Results in genetic STABILITY between generationsThis means each generation is IDENTICAL

What are the ADVANTAGES?

AdvantagesNo need to find a MATE (saves energy)Rapid population growth

What are the DISAVANTAGES?

DisadvantageNo VARIATION (all identical)

Types of Asexual Reproduction

MITOSIS MITOSIS is the process somatic cells (“body cells”) use

to divide in our body to promote growth and development in an organism. It is ASEXUAL reproduction.

Facts about MitosisDNA REPLICATES (copies itself)

before division# of divisions: 1# of daughter cells: 2Daughter cells are IDENTICAL

BRAINPOP!

http://www.brainpop.com/science/cellularlifeandgenetics/asexualreproduction/

Write the question and answer on the back of #4 Notes:Write question and Answer

1.What is asexual reproduction?

2.How many chromosomes are in the human body?

3.What is binary fission? Which organisms use it?

4.What is budding?

5.Does asexual reproduction create genetically different or identical offspring?

It’s The circle of cell life

How do cells reproduce and grow?

The Basics…

What must be present in EVERY cell?DNA!

What must happen BEFORE a cell divides?DNA REPLICATION!

WHAT IS THIS?WHAT IS THIS?

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Why do cells divide?Why do cells divide?

To To replacereplace other cells that have been other cells that have been damaged or worn outdamaged or worn out

To allow multicellular organisms to To allow multicellular organisms to growgrow

For For asexual reproductionasexual reproduction

Because they get Because they get too bigtoo big!!

What is MITOSIS?

Mitosis is the process by which the nucleus of one cell DIVIDES into two nuclei

Therefore, each cell has the same genetic material as the original cell

Its like “photocopying”(or CLONING) the cell- the two daughter cells are identical

Genetic InformationGenetic Information

Genetic information is Genetic information is contained in the DNAcontained in the DNA of of the cellthe cell

DNA is found in the thread-like coils called DNA is found in the thread-like coils called CHROMATINCHROMATIN when the cell is when the cell is NOT dividingNOT dividing

When the cell is dividing, When the cell is dividing, the chromatin the chromatin condenses (packs into) condenses (packs into) chromosomeschromosomes

genes are small sections of chromosomesgenes are small sections of chromosomes that that contain the information for a specific cell contain the information for a specific cell functionfunction

What makes up a chromosome?

DNA wrapped around PROTEINS!

The Big Picture

Human Chromosomes

The cell cycleThe cell cycle

Cell CycleCell Cycle

The cell The cell spends the spends the most amount of most amount of time in time in interphaseinterphase- - growinggrowing

Cell Cycle- InterphaseCell Cycle- Interphase

During INTERPHASE During INTERPHASE the cell is the cell is GROWING GROWING and preparing to and preparing to reproducereproduce

The cell’s The cell’s DNA is being DNA is being copiedcopied ( (replicatedreplicated))

The The DNADNA is in the form is in the form of loosely coiledof loosely coiled CHROMATINCHROMATIN

What happens during…

G1 Phase: The cell is Growing

S-Phase:Synthesis PhaseDNA is replicated (copied)

G2 Phase:Cell prepares for cell division

Cell Cycle- MitosisCell Cycle- Mitosis

Remember! Mitosis is the stage of the cell Remember! Mitosis is the stage of the cell cycle in which the cycle in which the nucleus nucleus and and cell cell dividesdivides

Mitosis is divided into:Mitosis is divided into:ProphaseProphaseMetaphaseMetaphaseAnaphaseAnaphaseTelophaseTelophase

**(Cytokinesis)****(Cytokinesis)**

Cell CycleCell Cycle

The cell The cell spends a very spends a very short amount short amount of time in of time in mitosismitosis- - dividingdividing

The phases of mitosis

ProphaseProphase ChromosoChromosomes are mes are

condensedcondensed and consist of and consist of 2 sister chromatids2 sister chromatids

The The nuclear membrane nuclear membrane begins to break downbegins to break down

Spindle fibers appearSpindle fibers appear

The The CENTROMERE joins CENTROMERE joins each pair of sister each pair of sister chromatidschromatids to the spindle to the spindle fiberfiber

MEMORY TRICK:MEMORY TRICK: PPro ro PPRIOR (1RIOR (1stst phase) phase)

MetaphaseMetaphase

Chromosomes line upChromosomes line up along the middle of along the middle of the cellthe cell

MEMORY TRICK:MEMORY TRICK:

MMetaphase = etaphase = MMiddleiddle

AnaphaseAnaphase Spindle fibers Spindle fibers separate separate sister chromatidssister chromatids and and pull them apartpull them apart

Once they have Once they have separated they are separated they are individual individual chromosomeschromosomes

MEMORY TRICK:MEMORY TRICK:

AAnaphase = naphase = AAwayway

TelophaseTelophase Spindle fibers Spindle fibers disassembledisassemble

Nuclear envelope Nuclear envelope reformsreforms

The nuclear envelope The nuclear envelope will become the nuclear will become the nuclear membranemembrane

MEMORY TRICK:MEMORY TRICK:

TTelophase = elophase = TTwo (new wo (new cells)cells)

CytokinesisCytokinesis

The The cytoplasm is dividedcytoplasm is divided between the two cells between the two cells

In In animal cells, cell membrane pinches off animal cells, cell membrane pinches off forming two new separate cellsforming two new separate cells

In In plant cells, cell membrane pinches off and a plant cells, cell membrane pinches off and a cell wallcell wall forms forms

Memory Trick: Memory Trick: CYTOCYTOplasm plasm CYTOCYTOkenisiskenisis

KEY FACTS ABOUT MITOSIS

What TYPE of cells? SOMATIC cells = BODY cells (skin, etc.)

WHEN? BEFORE cell division

WHY? REPLACE REPLACE worn out cellsworn out cells

GROWTH GROWTH of multicellular organismsof multicellular organisms

ASEXUAL ASEXUAL ReproductionReproduction

Because they cells get Because they cells get TOO BIG TOO BIG and and must dividemust divide

# of DIVISIONS? ONE (identical daughter cells)

# of DAUGHTER CELLS? 2 (identical) daughter cells

Genetic STABILITY or VARIATION? STABILITY (means IDENTICAL)

Mitosis in action!Mitosis in action!

BRAINPOP!

http://www.brainpop.com/science/cellularlifeandgenetics/mitosis/

Check Point

38

A

B

C

DE