Cell Biology The big picture So tell me what you know about cells So tell me why they are important So tell me the purpose of cells So tell me what’s inside a cell

Important questions What are cells? Why are they important? What’s the purpose of cells? What’s inside a cell?

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. There are plant cells as well as animal cells, the main difference between the two is that plant cells have a cell wall.

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, repair, and reproduction The length of time cells live can vary. For example, white blood cells only live for 2 weeks, red blood cells live for about four months, liver cells live about 1 year and 1/2, and nerve cells can live up to a life time.

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 the body's largest organ Every minute, 40,000 dead skin cells fall from your body. Over the course of life an individual sheds about 105 pounds of skin.

What's inside a cell Mitochondria Cytoplasm Ribosomes Nucleus Endoplasmic Reticulum Golgi Body Cell membrane Vacuole Lysosomes The one we as a class will focus on is the nucleus

Nucleus The nucleus is the “brain” of every cell Every cell has a nucleus Chromosomes are found inside the nucleus The cell nucleus acts like the brain of the cell. It helps control eating, movement, and reproduction. If it happens in a cell, chances are the nucleus knows about it

Candy Question 100,000 In your groups answer the following question. One square centimeter of your skin’s surface contains more than ________________ cells. 100,000 100,000

Purpose of cell division 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. What would happened if we could not repair our skin, organs, ect Which cells do not reproduce naturally in the body? brain and nerve

Two types of cell division Mitosis Meiosis

Mitosis Mitosis happens in order to create new identical cells Majority of cells under-go mitosis Main purpose of mitosis is growth and repair If mitosis is only for growth and repair, what kind of cells go through mitosis.

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

Prophase Metaphase Anaphase Telophase Chromosomes become visible, the nucleolus disappears. Metaphase The chromosomes become arranged in the center of the cell. Anaphase Chromosomes separate and then move to opposite sides of the cell. Telophase Chromosome reassemble at opposite sides of the cell and the nucleus reforms, around each set of chromosomes.

Meiosis 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. Only in sperm in males and Eggs in females

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

Compare and Contrast Mitosis and Meiosis Alike Different Both are cell reproduction to make new cells Both go through similar phases Mitosis results in two new cells which has 46 chromosomes and happens in most cells. Meiosis results in four new cells which has 23 chromosomes and happens only in sex cells.

Meiosis Mitosis 46 46 92 92 How many vowels in the word Meiosis, how many steps in Meiosis 46 46 46 46 23 23 23 23

Using the plastic chips show me: Mitosis Meiosis If you break your arm, what cell division takes place to repair the bone in your arm? Which cell division creates human reproduction cells? Represents the number of chromosomes 92 46 23

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