Cells Chapter 5

Cell Theory All living things are composed of cells. Cells are the basic unit of structure and function. All cells come from pre-existing cells.

Cell Structure Cell membrane- outer boundary of the cell Nucleus- control center Cytoplasm- material between the cell membrane and the nucleus

Speaking of NUCLEUS… Do all cells have a nucleus? Eukaryote: organism with a nucleus Prokaryote: single celled organism without a nucleus.

Cell Membrane Supports and protects the cell Regulates what may enter/exit Lipid bi-layer (picture) On the surface…

On the surface… Proteins act as pumps and channels. Carbohydrates act as name tags. Cell Wall only on plants, algae, and some bacteria.

Nucleus The information center of the cell (DNA & RNA) Nuclear envelope: 2 membranes that surround the nucleus Nucleolus: “little nucleus,” densely packed RNA Chromosomes: DNA attached to proteins for a new generation

Cytoplasm Contains many special organelles: Energy: Mitochondrion: change chemical food into usable energy (animal) Chloroplast: trap and convert sunlight (plant)

Protein Factories Ribosomes: contain RNA and proteins, location: free or attached to the RER.

Manufacturing and Shipping Endoplasmic Reticulum (ER) SER: store enzymes and chemicals RER: ribosomes for protein synthesis Golgi Apparatus: collects, packages, and ships proteins made in one area for use in another

Cleaning Crew: Lysosomes contain enzymes that may digest encircled material. (Animal)

Storage: Vacuoles, sac like structures may contain salt, water, carbohydrates, starch, pigments, etc.

Framework: Cytoskeleton: microtubules and microfilaments provide shape for the cell and allow movement in the cytoplasm Microtubules run across the cell Microfilaments run parallel to the membrane

Cilia: short hair-like, numerous Flagella: long whip-like, 1 or 2

Transport through the cell Passive transport does not require energy. Active transport requires energy.

Facilitated diffusion Osmosis Filtration Molecular pumps Endocytosis Passive Active Diffusion Facilitated diffusion Osmosis Filtration Molecular pumps Endocytosis Pinocytosis phagocytosis Exocytosis

Diffusion: movement of particles with the concentration gradient

Osmosis: the diffusion of ONLY water

Hypertonic refers to the environment outside the cell having a higher concentration of solute. Hypotonic refers to the environment outside the cell having a higher concentration of water. Isotonic environment refers to an environment that is the same inside and out.

Facilitated Diffusion: still moving with concentration gradient with the aid of another substance (catalyst) Filtration: moves with the pressure gradient rather than the concentration gradient

Molecular Pumps: proteins embedded in a cell surface selectively pump ions across the membrane. REQUIRE ENERGY!

Endocytosis Pinocytosis Phagocytosis

Exocytosis