Cell Structure

Organelles

B. Organelles (little organs)

1. Controla. Nucleus

-contains genetic material-stores DNA-surrounded by a doublemembrane with pores-directs all cell activities-contains the nucleolus

2. Energy Related i. Chloroplast (in plants only)

-Green -Contains pigment chlorophyll -Site of photosynthesis

2. Energy Related (cont.) b. Mitochondria

- “powerhouse of the cell”- Site of cellular respiration- Where ATP is formed

3. Membranous Sacs & Canals a. Endoplasmic reticulum (ER)

-miniature circulatory system-series of tubular canals-serves to transport materials

Smooth ER- transports lipidsRough ER-transports proteins

b. Ribosomes -small spherical structures -made of RNA -site of Protein Synthesis -may be free (in cytoplasm)

or -attached (on the rough ER)

c. Vacuole -sac -used for storage (food, water, etc.) -1 large in all plants, - several small in only some animals

d. Lysosome -storage sac -contains digestive enzymes - “suicide bag” Ex. Membranes present between fingers

and toes in early embryos

e. Golgi Body (Complex/Apparatus) -series of flattened sacs (disc-like) -packages cell secretions (products)

Ex. Goblet Cell & Mucous

4. Cytoskeleton & Movement

-give support and internal structure to cell-aid in moving organelles (form a track)-give support & internal structure to cell-important in muscle cell contraction

d. Flagellum -only on animal cells -long hair-like projection in whip-like motion -used to propel the cell -made of microtubules

e. Cilia -only in animal cells -used to propel cells

(uses an oar-like motion) -used in organisms to move materials

Ex. Line respiratory tract and move debris move egg cells down the fallopian tube

Plant vs. Animal Cells

Cell wall Rigid shape Chloroplasts 1 large vacuole

Lacks cell wall Flexible shape No chloroplasts Several small vacuoles Cilia & flagella may be

present