Reproduction

There are 2 kinds of reproduction: Asexual Reproduction Sexual Reproduction

Asexual Reproduction

Asexual Reproduction This type of reproduction involves only ONE parent organism (either unicellular or multicellular). Occurs by MITOSIS and cytoplasmic division The offspring contains the same DNA as the parent and is therefore a CLONE Ex: An ameba reproduces asexually by splitting in two

Types of Asexual Reproduction

Three types of Asexual Reproduction: Binary Fission Budding Regeneration

Binary Fission

I. Binary Fission The simplest form of asexual reproduction. Splitting of an organism into 2 or more individuals of equal size

Where is the Parent? No parent is left! The parent has become two individuals Organisms that perform Binary Fission are: paramecium, bacteria, ameba

Budding

II. Budding The parent organism divides into two parts that are unequal Budding differs from binary fission because the parent and the offspring are not the same size Ex: Hydra, Yeast

Regeneration

III. Regeneration A new individual can arise from a segment of an existing organism Helpful for replacement of injured or lost body parts Ex: Starfish, Planarian, Worms

Mitosis

Mitosis Our body cells, such as skin and hair, reproduce asexually by splitting and dividing through a process we call MITOSIS Mitosis is used when cells/tissues need to grow and repair

Mitosis creates clones of the parent cell Body cells contain 46 chromosomes (the Diploid number)

DNA

What is DNA? All the information needed to create an entire organism is encoded in DNA DNA is segmented into Genes A single molecule of DNA has thousands of genes lined up like train cars

Chromosomes DNA is coiled into a structure called a chromosome When DNA is copied – the exact copy is called a chromatid Two chromatids are joined by a centromere

Single-Stranded Chromosomes

Stages of Mitosis

Mitosis

Cell Division Animation

Mitosis in Animal Cell

Mitosis in Plant Cell

Mitosis gone wrong: Cancer

What is Cancer? Sometimes body cells do not respond to normal control mechanisms, and continue to divide as long as nutrients are available Eventually a tumor forms If cancer cells remain at the original site they are considered benign

If they spread to neighboring tissues, they are considered malignant This spread of cancerous cells beyond the original site is called metasasis May be treated with high energy radiation and poisonous chemicals (chemotherapy)