AP BIO CH 6-7 test prep

Prokaryotes

Prokaryotes

No nucleus
DNA in nucleotide
bacteria & archea
fast @ reproducing
no organelles other than ribosomes

Eukaryotes

Has a nucleus
Has membrane-bound organelles
protists, fungi, plants, animals
larger/compex

Nucelus

Control center of the cell

DNA & mRNA

surrounded by double membrane

Ribosomes

synthesize protein according to mRNA

It consists of two subunits that are NOT membrane-enclosed

• Made of RNA and proteins

Free & Bound Ribosomes

Free (float in the cytosol; produce proteins WITHIN the cells)
bound ( attached to ER; make proteins for EXPORT from the cell)

Endoplasmic Reticulum (ER)

Network of membrane tubes within the cytoplasm of eukaryotic cells

• provides mechanical support

Rough & Smooth ER

Rough ER (packaging newly synthesized proteins)

Smooth ER (Does not have ribosomes attached; for detoxification and lipid synthesis)

Glogi Apparatus

flattened membrane-bound sacs found in eukaryotic cells
for folding/modification/packaging of proteins

Cis-face & Trans-face

Cis (reciving vescicles)
Trans (shipping vescicles)

Lysosomes

for intracellular digestion; recycle cell's materials
cell death "apoptosis"
contains hydrolytic enzymes

Vacuoles

membrane-bound vesicles
storage of materials

In plants ~ retention of water

Mitochondria

site of cellular respiration
Outer membrane (smooth)
Inner membrane (has folds called cristae)
for the production of ATP

Chloroplats

site of photosynthesis
contains chlorophyll (pigments) for capturing sunlight
thylakoid (highly folded membranes)
stroma (fluid between inner chloroplast membrane & outer thyalkoids)

Cytoskeleton

network of fibers extending throughout the cytoskeleton
microtubules, microfilaments, intermediate filaments (all maintain cell shape)

Plasma membrane

selectively-permeable phospholipid bilayer
heads polar; hydrophilic
tail nonpolar; hydrophobic

Fluid mosaic model

fluid (membrane itself)
mosaic (phospholipids, proteins, carbs)
~ wedged between membrane

Integral & Peripheral Proteins

Integral (embedded in membrane)
Peripheral (sides of membrane; not embedded; held in place by cytoskleleton)

Membrane permeability

• small nonpolar molecules can pass freely

• hydrophilic/polar molecules cannot easily pass

• can get across through proteins

Cell Wall: Structural boundary and permeable barrier

Channel & Carrier Proteins

• Channel Protein (hydrophilic tunnel; allows specific target molecules to pass through)

• Carrier Protein (spans the membrane and changes shape to transport molecule)

Passive Transport (Diffusion)

Net movement of molecules from HIGH to LOW concentration - Without energy needed
DOWN concentration gradient
w/ transport protien

Active Transport

LOW to regions of HIGH concentration
requires energy (ATP)
AGAINST concentration gradient

Cotransport

uses energy from an electrochemical gradient to transport:
Symport (transported in the same direction)
Antiport (transported in different directions)

Osmosis

diffusion of water across a selectively permeable membrane
Large quantities of water move via aquaporins
Solute (being dissolved)
Solvent (dissolves solute)

Hypertonic

more solute, less solvent
(less water)
SHRIVLED

Isotonic

equal concentrations of solute and solvent
NORMAL

Hypotonic

less solute, more solvent
(more water)
LYSED/ pops

Water Potential

free energy of water
addition of solute decreases & decreases water potential
Membrane Functions

Diffusion & Facilitated Difussion

Diffusion - SMALL NONPOLAR MOLECULES PASS FREELY
Small amounts of very small polar molecules, like water, can diffuse across the membrane
Facilitated Diffusion - through transport proteins
Large and small polar molecules

Bulk Transport

Endocytosis (takes in molecules by forming new vesicles)
Exocytosis (secretes molecules by fusion of vesicles with membrane)
Phagocytosis (cell takes in large particles)
Pinocytosis (cells takes in extracellular fluid containing dissolved substances)

Surface Area to Volume

the smaller the cell, the more surface area, the more efficient
x. plant roots & small intestine (villi, micro-villi)

Endosymbiotic theory

mitochondria and chloroplasts has similar origin
prokaryotic cells engulf larger cell

Evolution of Membrane-Bound Organelles

• mitochondria & chloroplasts evolved from previously free-living prokaryotes (endosymbiosis)

Mitochondria Evolution

aerobic prokaryotic cell was engulfed by an anerobic cell
cell did not get digested; became mutual

Chloroplast Evolution

photosynthetic prokaryotic cell was enfgulfed by another cell
cell did not get disgested; became mutual

Endosymbiotic Orangelles & Their Ancestors

both mitochondria & cholorplasts have double-membranes
Like prokaryotic cells. . .
both have their own circular DNA
both have their own ribosomes for protein synthesis