1. Notes – Chapter 6 – The Cell part 1

2. Prokaryotic Cells Eukaryotic Cells domains Bacteria & Archaea 1-10 μm
DNA located in nucleoid
region
cell wall
capsule
pili
flagella
domain Eukarya (protists,
fungi, plants, & animals) μm
DNA located in nucleus
organelles
plasma membrane
cytosol/cytoplasm
ribosomes
chromosomes

3. Limits on Cell Size
as a cell increases in size, its volume grows proportionally more than its surface area
cells need a surface area large enough to accommodate its volume
if the surface area : volume ratio is too great, the rate of chemical exchange with the environment may be too slow to meet the cell’s needs

4. Generalized Animal Cell

5. Generalized Plant Cell

6. Nucleus contains most of the cell’s genes
directs protein synthesis by synthesizing mRNA
surrounded by a porous double membrane called the nuclear envelope
DNA is organized into chromosomes (made up of chromatin)
nucleolus – sythesizes rRNA (ribosomal subunits)

7. Ribosomes made of rRNA and protein carry out protein synthesis
free ribosomes make proteins that function within cytosol
bound ribosomes make proteins destined for insertion into membranes, for packaging within organelles, or for secretion

8. Endomembrane System
consists of membranes related through direct physical continuity or by vesicles
includes:
nuclear envelope
endoplasmic reticulum
Golgi apparatus
lysosomes
vacuoles & vesicles
plasma membrane

9. Endoplasmic Reticulum
continuous with nuclear envelope
rough ER
has ribosomes attached to surface
makes secretory proteins
makes membrane
smooth ER
lacks ribosomes
synthesizes lipids
metabolizes carbohydrates
detoxifies drugs/poisons
stores calcium ions

10. Golgi apparatus consists of flattened membranous sacs two poles:
cis = receiving end
trans = shipping end
modifies products of ER, stores them, “tags” them, & sends them to other destinations
manufactures macromolecules (ex: polysaccharides)

11. Lysosome contains hydrolytic enzymes
fuse with vesicles or vacuoles to…
digest macromolecules
recycle organic material (ex: old organelles)
break down food
destroy invaders

12. Vacuoles
similar to lysosomes because they carry out hydrolysis in plant & fungal cells
food vacuoles store & break down food
contractile vacuoles pump excess water out of cell
central vacuole of plant cells stores organic compounds & ions, acts as a disposal site for waste, contains pigments, and may contain poisons for defense against predators