Introduction to Cells

Learning Objectives• We will learn the 3 statements made by Cell

Theory

• We will contrast the two types of cells.

• We will review the basic structure of animal and plants cells

• We will review the structures that are unique to a plant cell.

History of Thought on Cells

• 1660’s Early Microscopes; Bacteria observed

• 1838 Understood that all plants are made of Cells

• 1855 Understood that all animals are made of Cells

The 3 statements of Cell Theory

1) All Living Things are Made of Cells

• If it is living it is made of cells, from a blue whale to a bacteria

• It may be made of one cell or millions of cells

2) Cells are the Basic Unit of Life

• If you divide a cell into its parts, the parts will not meet all the characteristics of a living thing. (They will not even continue to live for very long)

3) Cells come from Cells

• Life does not spontaneously arise from the air or something else. They are produced by preexisting cells.

The Two Cell Types

Two Main Types of Cells

• Prokaryotic Cells!

• NO nucleus or organelles (except ribosomes which have no membrane)

Two Main Types of Cells• Eukaryotic Cells!

• Have membrane bound organelles (like the nucleus)

Plants, animals and Fungi

are all made of eukaryotic cells

A Basic Animal Cell

Cytoplasm

• The liquid part of the cell

Organelles

• The structures in the cell

• Means “little organs”

Nucleus

• The brain or control center of the cell

• Contains the genetic information of the cell

Cell Membrane• The thin

flexible layer that encloses the cell

• Controls what leaves and enters the cell

Mitochondria• The

powerhouse of the cell

• Sugar is changed into a form of energy the cell can use

Ribosomes

• “The little dots” is what the arrow is pointing to

• This is where proteins are put together

Basic Plant Cell

Plant Cells have structures not found in animal cells Cell Wall, Chloroplasts and Central Vacuole

Basic Plant Cell

The cell wall is outside the cell membrane. It is a rigid structure that protects the cell

and helps the cell keep its shape

Basic Plant Cell

The central vacuole is a large organelle that stores water for the plant cell

Basic Plant Cell

The chloroplast captures the energy of sunlight and converts it into sugar.

This is photosynthesis.

Review Questions

• What are the three things cell theory tells us?

• What are the two types of cells?

• What are the basic organelles in an animal cell?

• What three structures are unique to plant cells?

The End