Cell Reproduction How do cells make new cells

Cell Reproduction How do cells make new cells?

Cell Reproduction • Reproduce: process by which living things give rise to other living things – Two Types of Cell Reproduction • Asexual: one parent offspring is identical • Sexual: two parents offspring is not identical

Types of Asexual Reproduction • Binary Fission – Primary way that bacteria (unicellular) cells reproduce

Budding • Usually seen in yeast cells • Cell replicates when a piece of the cell pinches off and separates from the parent cell

Spore • Found in fungi, algae, protozoa • Airborne cells that are released from the parent. They are enclosed and developed when the environment is appropriate

Regeneration • Ability to re-grow lost parts • Found in starfish, earthworms, some reptiles

Vegetative Propagation • Regeneration in plants from an area that is remaining

Mitosis • The process where animal cells divide • This is a type of asexual reproduction • Body cells (somatic cells) go through the process of mitosis

Sexual Reproduction in cells • Meiosis – Process where sex cells are made in the gonads • Gonads organs where sex cells are made – Male testes make and house sperm – Females ovaries make and house eggs We will discuss meiosis later!!!!

Cell Cycle • Why is the cell cycle called a cycle? • Why do you think it’s important for a cell to grow in size during its cell cycle?

Cell Cycle- The Cell’s Timeclock

What happens in each stage cell reproduction?

Interphase: not part of mitosis • Interphase-(technically not part of mitosis, but it is included in the cell cycle) • Cell is in a resting phase, performing cell functions • DNA replicates (copies) • Organelles double in number, to prepare for division – G 1 - First growth – S - synthesis (copy DNA) – G 2 - Second growth

Process of Mitosis

Prophase • • Spindle forms Centrioles move to opposite poles Chromosomes become visible Nuclear membrane breaks down in prometaphase

Metaphase • Chromosomes line up along the equator

Anaphase • Centromeres divide • Chromatids separate and move to opposite poles

Telophase • Nuclear membrane forms around each group of chromosomes • Chromosomes unwind, nuclear membrane forms again

Cytokinesis begins • Cell pinches inward and forms two daughter cells

Visit Biology Corner • www. biologycorner. com Click on the images link on the top Scroll on the right hand side where the animations section is then scroll down to cells and look for any animation on mitosis to look at

Results of Mitosis • Same number of chromosomes from generation to generation (46 in humans) • Each daughter cell (offspring) gets exact copy of chromosomes

Consequences of Incorrect Mitosis • Cancer: uncontrolled mitotic division in cells – Timeclock does not work properly

Plant Mitosis • Same process as in animal cell but plants don’t have the centrioles

Uses for Mitosis • Replicate young embryonic cells • Replicate body (somatic) cells. Skin, blood cells • Repair damaged cells • Controls cell growth and death. – Cytokinins: chemicals that regulate cell replicating