The Big Picture Cell Biology What are cells

The Big Picture Cell Biology

What are cells? Cells are the basic unit of structure and function of living things. You are made of trillions of specialized cells all working together.

Why are cells important? Cells help keep living things alive Some of the functions of cells are: Obtaining oxygen Getting rid of wastes Obtaining food Growth and repair

What’s the purpose of cells? Cells help us stay alive and reproduce Cells in your lungs provide oxygen for your body Cells in your stomach provide energy by digesting food Cells in your muscles protect your weaker organs

What's inside a cell? • • • Mitochondria Cytoplasm Ribosomes Nucleus Endoplasmic Reticulum • • Golgi Body Cell Membrane Vacuole Lysosomes

Nucleus The nucleus is the “brain” of every cell Every cell has a nucleus Chromosomes are found inside the nucleus

Quick Group Brainstorm In your groups answer the following question. One square centimeter of your skin’s surface contains more than ________ cells. 100, 000

Two types of cell division Mitosis Meiosis

Purpose of cell division (Mitosis) The purpose of cell division is to take one cell and make two new identical “daughter” cells. Cells need to divide for reproduction, growth, and for repair.

Mitosis happens in order to create new identical cells Majority of cells under-go mitosis Main purpose of mitosis is growth and repair

Mitosis 46 92 Parent Cell DNA replicates 46 x 2 = 92 46 46 Two new identical daughter cells

Meiosis only occurs in sex cells The only purpose for meiosis is for reproduction The result of meiosis is four new cells with HALF the number of chromosomes.

Meiosis Parent Cell 46 DNA replicates 92 46 23 DNA splits 46 23 23 23 DNA splits again

Play-doh Cells With a partner, you will be modeling what changes cells go through during mitosis and meiosis. Using play-doh, model a cell going through mitosis and meiosis. Be sure to include the proper number of parent cells and daughter cells. Use your resources if you are unclear on anything.

Meiosis Mitosis 46 46 92 92 46 46 46 23 23 46

Mitosis and Meiosis How are they Different? Mitosis Occurs in every cell Divides once Makes identical copies For growth and repair Occurs your entire life Meiosis Only in sex cells Divides twice Makes different copies For reproduction Occurs during PART of your life.

Compare and Contrast Mitosis and Meiosis HOW ARE THEY ALIKE? Both make new cells Both go through similar phases

Summary How does mitosis and meiosis connect to cell theory? (Write your answer on the bottom of your notes)