Cell Division

You started as a cell smaller than a period at the end of a sentence… Where it all began… You started as a cell smaller than a period at the end of a sentence… .

Why do the nuclei need to be identical? How Do Cells Divide? Cell’s divide through a process called mitosis. Mitosis takes the nucleus of the cell and divides it into two. These two nuclei are identical. Why do the nuclei need to be identical?

WHAT IS DNA? In the nucleus is the cell’s DNA. DNA gives you your specific traits! It is the code that makes you who you are! Hair color Eye color Height

Getting Started The DNA is wound up into a chromosome. Unwound DNA is called chromatin. Think of a ball of yarn… chromatin chromosome

Chromosomes Most human cells have 23 pairs of chromosomes. This includes a pair of chromosomes determine our gender. XY chromosome means your are a male XX chromosome means you are a female.

Cell Division Mitosis in a Nutshell Cell division increases the number of cells and causes many-celled organisms to grow. Cells have life cycles. Mitosis Life Cycle Mitosis in a Nutshell

How Does Cell Division Happen? Occurs in a series of phases, or steps. Interphase Prophase Metaphase Anaphase Telophase

Interphase Period of growth and development in a cell’s life cycle. During interphase, a cell duplicates its chromosomes and prepares for cell division Cell’s are in interphase the longest time TIME

Starting Mitosis After interphase, the nucleus divides, and then the cytoplasm separates to form two new identical cells. This process is called mitosis. There are 4 steps in mitosis. Animal cells have centrioles which help them divide.

Prophase Chromosomes becomes visible The nuclear membrane dissolves Centrioles move to opposite ends of the cell

Metaphase Chromosomes line up Spindle fibers form

Anaphase Chromosomes separate The spindle fibers pull the chromosomes apart

Telophase Cytoplasm Divides A new nucleus forms Spindle fibers disappear

The End Result Mitosis in a Nutshell TADA! You have two new cells! These cells are identical. This is because they reproduced asexually. Mitosis in a Nutshell

Organisms can COPY themselves another way too…

Asexual Reproduction In asexual reproduction, a new organism is produced from one organism. The new organism will have heredity (DNA) material identical to the heredity material of the parent organism.

Examples of Asexual Reproduction MITOSIS!!!!!! HELLO!!!!!!

Examples of Asexual Reproduction Regeneration - a whole new organism grows from each piece of the parent.  For example – sponges, planaria, and sea stars

Examples of Asexual Reproduction Budding – a small, exact copy of the adult grows from the body of the parent.  For example – Hydra

Examples of Asexual Reproduction Fission - an organism with no nucleus that divides into two identical organisms.  For example – Bacteria