Name: Sect: Date:

Cells

Cell Theory

The cell theory is a widely accepted explanation of the relationship between cells and living things. The cell theory states:

·  ______

·  ______

·  ______

Types of Cells

·  Prokaryotic- ______

·  Eukaryotic- ______

Cells Have Basic Needs

Living organisms have basic needs because their cells have basic needs. Cells, like organisms, typically need:

·  ______

·  ______

·  ______

·  ______

Typical Plant Cell

Organelle / Structure / Function / Analogy
cell wall / rigid and flexible layer that surrounds and protects plant cells
cell membrane / selectively permeable layer (controls what enters or leaves)
cytoplasm / gel-like fluid that fills the cell and surrounds the organelles
Organelle / Structure / Function / Analogy
nucleus / directs all of the cell’s activities; the “brain” of the cell
nucleolus / found in the nucleus; produces ribosomes and proteins
chromatin / / found in the nucleus; contain the “instructions” to run the cell
ribosomes / produce proteins; found floating in cytoplasm or attached to the endoplasmic reticula
mitochondria / / site of cellular respiration; where sugars are broken down for energy
chloroplasts / contain chlorophyll and give plants green color; where photosynthesis occurs
lysosomes / / break down food or toxic molecules
golgi body / / packages the proteins made by the ribosomes to be sent to other parts of the cell
endoplasmic reticulum / / system of passageways that move materials like proteins around the cell
vacuoles / storage area for food, water and waste in a cell; help plants remain ridgid

Plant cells and animal cells contain different cellular structures. For example, most plant cells possess a cell wall and chloroplasts. Animal cells never contain these structures. Plant cells also always contain large vacuoles. Some animal cells also have vacuoles, but the vacuoles in animal cells are much smaller than those found in plant cells.

The Cell in its Environment

·  The cell membrane acts as the ______for the cell

·  It is ______to substances

o  This means it can what ______

o  “permeable” means substances can ______

·  substances move in and out of the cells by one of three methods:

1.  ______

2.  ______

3.  ______

1. Diffusion

·  method by which small molecules move into and ______

·  molecules move from higher to lower ______

·  Example-

2.  Osmosis – the diffusion of water molecules.

·  molecules move from high to low concentration

·  Ex:

o  Water moves from high water concentration on the left to low water concentration on the right.

•  Diffusion and osmosis are PASSIVE transport; they require NO energy.

3. Active transport

·  movement of molecules which ______

·  Move from ______concentration to ______concentration (opposite of diffusion or osmosis)

·  Two methods of active transport:

§  Transport proteins- help carry molecules into and out of a cell by using energy

§  Engulfing-cell membrane surrounds and engulfs the material. This engulfed material then pinches off forming a vacuole