Inner Membrane Folded into cristae. Amount of folding depends on the level of cell activity. Contains many enzymes. ATP generated here.

Function Cell Respiration - the release of energy from food. Major location of ATP generation. “Powerhouse” of the cell.

Mitochondria Have ribosomes (small size). Have their own DNA. Can reproduce themselves. May have been independent cells at one time.

Chloroplasts Structure - two outer membranes. Complex internal membrane. Fluid-like stroma is around the internal membranes.

Inner or Thylakoid Membranes Arranged into flattened sacs called thylakoids. Some regions stacked into layers called grana. Contain the green pigment chlorophyll.

Function Photosynthesis - the use of light energy to make food.

Chloroplasts Contain ribosomes (small size). Contain DNA. Can reproduce themselves. Often contain starch. May have been independent cells at one time.

Plastids Group of plant organelles. Structure - single membrane. Function - store various materials.

Examples Amyloplasts/ Leucoplasts - store starch. Chromoplasts - store hydrophobic plant pigments such as carotene.

Ergastic Materials General term for other substances produced or stored by plant cells. Examples: Crystals Tannins Latex Resins

Cytoskeleton Network of rods and filaments in the cytoplasm.

Functions Cell structure and shape. Cell movement. Cell division - helps build cell walls and move the chromosomes apart.

Components Microtubules Microfilaments Intermediate Filaments

Microtubules Structure - small hollow tubes made of repeating units of a protein dimer. Size - 25 nm diameter with a 15 nm lumen. Can be 200 nm to 25 mm in length.

Tubulin Protein in microtubules. Dimer - a and b tubulin.

Microtubules Regulate cell shape. Coordinate direction of cellulose fibers in cell wall formation. Tracks for motor molecules.

Microtubules Form cilia and flagella. Internal cellular movement. Make up centioles, basal bodies and spindle fibers.

Cilia and Flagella Cilia - short, but numerous. Flagella - long, but few. Function - to move cells or to sweep materials past a cell.

Cilia and Flagella Structure - 9+2 arrangement of microtubules, covered by the cell membrane. Dynein - motor protein that connects the tubules.

Dynein Protein A contractile protein. Uses ATP. Creates a twisting motion between the microtubules causing the structure to bend or move.

Centrioles Usually one pair per cell, located close to the nucleus. Found in animal cells. 9 sets of triplet microtubules. Help in cell division.

Basal Bodies Same structure as a centriole. Anchor cilia and flagella.

Basal Body

Microfilaments 5 to 7 nm in diameter. Structure - two intertwined strands of actin protein.

Microfilaments are stained green.

Functions Muscle contraction. Cytoplasmic streaming. Pseudopodia. Cleavage furrow formation. Maintenance and changes in cell shape.

Intermediate Filaments Fibrous proteins that are super coiled into thicker cables and filaments 8 - 12 nm in diameter. Made from several different types of protein.

Functions Maintenance of cell shape. Hold organelles in place.

Cytoskeleton Very dynamic; changing in composition and shape frequently. Cell is not just a "bag" of cytoplasm within a cell membrane.

Cell Wall Nonliving jacket that surrounds some cells. Found in: Plants Prokaryotes Fungi Some Protists

Plant Cell Walls All plant cells have a Primary Cell Wall. Some cells will develop a Secondary Cell Wall.

Primary Wall Thin and flexible. Cellulose fibers placed at right angles to expansion. Placement of fibers guided by microtubules.

Secondary Wall Thick and rigid. Added between the cell membrane and the primary cell wall in laminated layers. May cover only part of the cell; giving spirals. Makes up "wood”.

Middle Lamella Thin layer rich in pectin found between adjacent plant cells. Glues cells together.

Cell Walls May be made of other types of polysaccharides and/or silica. Function as the cell's exoskeleton for support and protection.

Extracellular Matrix - ECM Fuzzy coat on animal cells. Helps glue cells together. Made of glycoproteins and collagen. Evidence suggests ECM is involved with cell behavior and cell communication.

Intercellular Juctions Plants-Plasmodesmata

Plasmodesmata Channels between cells through adjacent cell walls. Allows communication between cells. Also allows viruses to travel rapidly between cells.

Intercellular Juctions Animals: Tight junctions Desmosomes Gap junctions

Tight Junctions Very tight fusion of the membranes of adjacent cells. Seals off areas between the cells. Prevents movement of materials around cells.

Desmosomes Bundles of filaments which anchor junctions between cells. Does not close off the area between adjacent cells. Coordination of movement between groups of cells.

Gap Junctions Open channels between cells, similar to plasmodesmata. Allows “communication” between cells.

Summary Answer: Why is Life cellular and what are the factors that affect cell size? Be able to identify cellular parts, their structure, and their functions.

Cell Animation Link http://multimedia.mcb.harvard.edu/anim_innerlife_hi.html You may need to replay this several times to catch all of the parts.