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 generations  This means each generation is IDENTICAL

What are the ADVANTAGES? Advantages  No need to find a MATE (saves energy)  Rapid population growth

What are the DISAVANTAGES? Disadvantage  No 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 Mitosis DNA REPLICATES (copies itself) before division # of divisions: 1 # of daughter cells: 2 Daughter cells are IDENTICAL

BRAINPOP! eandgenetics/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? 15

Why do cells divide? To replace other cells that have been damaged or worn out To replace other cells that have been damaged or worn out To allow multicellular organisms to grow To allow multicellular organisms to grow For asexual reproduction For asexual reproduction Because they get too big! Because they get too 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 Information Genetic information is contained in the DNA of the cell Genetic information is contained in the DNA of the cell DNA is found in the thread-like coils called CHROMATIN when the cell is NOT dividing DNA is found in the thread-like coils called CHROMATIN when the cell is NOT dividing When the cell is dividing, the chromatin condenses (packs into) chromosomes When the cell is dividing, the chromatin condenses (packs into) chromosomes genes are small sections of chromosomes that contain the information for a specific cell function genes are small sections of chromosomes that contain the information for a specific cell function

What makes up a chromosome? DNA wrapped around PROTEINS!

The Big Pictur e

Human Chromosomes

The cell cycle

Cell Cycle The cell spends the most amount of time in interphase- growing The cell spends the most amount of time in interphase- growing

Cell Cycle- Interphase During INTERPHASE the cell is GROWING and preparing to reproduce During INTERPHASE the cell is GROWING and preparing to reproduce The cell’s DNA is being copied (replicated) The cell’s DNA is being copied (replicated) The DNA is in the form of loosely coiled CHROMATIN The DNA is in the form of loosely coiled CHROMATIN

What happens during… G1 Phase:  The cell is Growing S-Phase:  Synthesis Phase  DNA is replicated (copied) G2 Phase:  Cell prepares for cell division

Cell Cycle- Mitosis Remember! Mitosis is the stage of the cell cycle in which the nucleus and cell divides Remember! Mitosis is the stage of the cell cycle in which the nucleus and cell divides Mitosis is divided into: Mitosis is divided into:  Prophase  Metaphase  Anaphase  Telophase **(Cytokinesis)**

Cell Cycle The cell spends a very short amount of time in mitosis- dividing The cell spends a very short amount of time in mitosis- dividing

The phases of mitosis

Prophase Chromoso mes are condensed and consist of 2 sister chromatids Chromoso mes are condensed and consist of 2 sister chromatids The nuclear membrane begins to break down The nuclear membrane begins to break down Spindle fibers appear Spindle fibers appear The CENTROMERE joins each pair of sister chromatids to the spindle fiber The CENTROMERE joins each pair of sister chromatids to the spindle fiber MEMORY TRICK: MEMORY TRICK: Pro  PRIOR (1 st phase) Pro  PRIOR (1 st phase)

Metaphase Chromosomes line up along the middle of the cell Chromosomes line up along the middle of the cell MEMORY TRICK: MEMORY TRICK: Metaphase = Middle Metaphase = Middle

Anaphase Spindle fibers separate sister chromatids and pull them apart Spindle fibers separate sister chromatids and pull them apart Once they have separated they are individual chromosomes Once they have separated they are individual chromosomes MEMORY TRICK: MEMORY TRICK: Anaphase = Away Anaphase = Away

Telophase Spindle fibers disassemble Spindle fibers disassemble Nuclear envelope reforms Nuclear envelope reforms The nuclear envelope will become the nuclear membrane The nuclear envelope will become the nuclear membrane MEMORY TRICK: MEMORY TRICK: Telophase = Two (new cells) Telophase = Two (new cells)

Cytokinesis The cytoplasm is divided between the two cells The cytoplasm is divided between the two cells In animal cells, cell membrane pinches off forming two new separate cells In animal cells, cell membrane pinches off forming two new separate cells In plant cells, cell membrane pinches off and a cell wall forms In plant cells, cell membrane pinches off and a cell wall forms Memory Trick: CYTOplasm  CYTOkenisis Memory Trick: CYTOplasm  CYTOkenisis

KEY FACTS ABOUT MITOSIS What TYPE of cells?SOMATIC cells = BODY cells (skin, etc.) WHEN?BEFORE cell division WHY? REPLACE worn out cells REPLACE worn out cells GROWTH of multicellular organisms GROWTH of multicellular organisms ASEXUAL Reproduction ASEXUAL Reproduction Because they cells get TOO BIG and must divide Because they cells get TOO BIG and must divide # of DIVISIONS?ONE (identical daughter cells) # of DAUGHTER CELLS?2 (identical) daughter cells Genetic STABILITY or VARIATION?STABILITY (means IDENTICAL)

Mitosis in action!

BRAINPOP! eandgenetics/mitosis/ eandgenetics/mitosis/

Check Point 38 A B C D E