CELLS

Essential question: What is the cell theory? Units of Life Cells): History: Anton van Leeuwenhoek: a. First to observe organisms. b. Designed own microscope.

Robert Hooke Studied cork cells. Coined the word “cell”.

Cell Theory: Cells are the basic unit of structure. Cells are the basic unit of function. All cells came from preexisting cells.

Exceptions to the Cell Theory Since all cells came from cells, what produced the first cell? Viruses are not composed of cells and do no carry on most cellular activities, except for reproduction and synthesis. Mitochondria and chloroplast contain their own genetic material and can reproduce independently.

Essential question: What are the types of cells? Prokaryotes-cells without a nucleus. Ex. bacteria Eukaryotes-cells with a nucleus.

Essential question: What is an organelle? Organelles ( parts ) of a Cell: Organelle -part of a cell with a specific function.

Essential Questions: What is the structure of the cell membrane Essential Questions: What is the structure of the cell membrane? What is the functions of the nucleus, nucleolus, and ribosomes?

Cell Wall and Cell Membrane Found only in plant. Provides support and protection. Made up of cellulose (CH0). Cell Membrane: Controls the passage of materials in and out of the cells, thus protects the cell. Said to be selectively permeable. Composed of two layers of phospholipids, cholesterol and protein channels.

Phospholipid - lipids (fats) with phosphate group.

Nucleus: Control center of the cell. Protected by two membranes (nuclear membrane). Contains genetic information (chromosomes)

Nucleolous and Ribosome Nucleolus: Found in the nucleus. Makes ribosomes. Ribosome: Site of protein synthesis. Found floating in the cytoplasm or attached to the endoplasmic reticulum.

Essential Questions: What are the functions of ER, Cytoplasm, Cytoskeleton and Golgi bodies?

Endoplasmic Reticulum (ER) Series of interconnecting membranes. Involved in storage , synthesis, and transport of substances (mainly proteins). Two types of ER: Smooth-Has no ribosomes attached. Rough- Has ribosomes attached.

Cytoplasm: Fluid-like environment between the nucleus and the cell membrane. Where organelles are suspended and where many biochemical processes occur. Cytoskeleton: Skeleton of the cell. Constantly changing.

Golgi Complex: Series of small membrane-bound sacs. Involved in making secretions. Sorts proteins into packages to be sent out. Ex. Post office

Essential Questions: What is the functions of the following organelles: Vacuole, Lysosome, chloroplast, Mitochindria. What is difference between cilia and flagella?

Vacuole: Temporary storage area for materials. Exs Vacuole: Temporary storage area for materials. Exs. Food, waste products, water and enzymes. Lysosmes: Contain digestive enzymes. Involved in digestion of worn out organelles and food particles.

Chloroplast: Chloroplast: Found only in plant cells. Contains a green pigment called chlorophyll that traps light energy. Site of photosynthesis.

Mitochondria: Double membrane structure. Site of respiration, thus provides energy for the cell.

Cilia and Flagella Some cell surfaces have cilia and flagella, which are structures that aid in locomotion or feeding. Cilia- short, numerous hair like projections that move in a wave like motion. Flagella-Long projections that move like a whip.

Essential Question: What are the differences between plant and animal cell?

Plant Cells Versus Animal Cells Organelle Plant Cell Animal Cell chloroplast present absent vacuole large small cell wall central shape rectangular round .

Cell Measurement: The very small size of most cells requires the use of a small unit for measurement. This unit is known as the micrometer ( u m ). Cells often have diameters of only 10-50 u m. 1,000 u m = 1 mm