AP Bio unit 2

Ribosomes

• made of rRNA and proteins

• Synthesize proteins according to the sequence carried by the messenger RNA

Endomembrane system

A system of membrane bound components that modify, package and transport proteins, lipids, and polysaccharides inside eukaryotic cells

Endoplastic reticulum

Membrane network that allows cell to maintain shape (also plays a role in transport)

Smooth ER

synthesizes lipids and detoxifies cells

Rough ER

rough due to stuck ribosomes; organizes and compartmentalize the cell while producing, processing and transporting proteins

Golgi Apparatus

Series of flattened membrane sacs that package proteins for shipping; also folds and chemically modifies newly synthesized cellular products

Mitochondria

has a double membrane; outer is smooth, inner is folded

powerhouse of the cell

produces ATP

Double membrane of mitcochondria purpose

creates compartments for metabolic reactions involved in aerobic cellular respiration

Aerobic cellular respiration

metabolic process in which cells use oxygen to break down glucose and nutrients to produce chemical energy in the form of ATP; releases carbon dioxide as waste

Chloroplast

organelles found in plants and photosynthetic algae

has double membrane; where photosynthesis occurs

Lysosome

enclosed organelle

contains hydrolytic (digestive) enzymes

digest nutrients & breaks down waste

can release enzymes to destroy cell when damaged

Vacuole

Membrane bound sacs

stores cellular material in animal cells

Plant cell vacuole

one large singula-called the central vacuole; stores water and nutrients to maintain tugor pressure

The larger a cell becomes…

the less efficient it is at exchanging the materials needed to stay alive

cells should maintain a

high surface area to volume ratio

Phospholipids

a lipid molecule made of a head and a tail that form a lipid bilayer

Phosphate head

Hydrophillic, polar or water loving

Fatty acid tail

non polar; hydrophobic

Proteins in the bilayer are usually

non-polar

Proteins in the plasma membrane

Transports nutrients and signals or triggers cellular responses

Steroids

aka sterol or cholesterol

lipid in the plasma membrane that regulates membrane fluidity and stability

Glycoproteins and Glycolipids

Have carbohydrate sugar chains attached to them

Functions as hormone receptor

Selective Permeability

Allows certain substances to cross more easily than others

ex: smaller, nonpolar molecules can pass easier

ex:nitrogen, oxygen and carbon dioxide

How do small, polar, uncharged molecules pass through the membrane ex: water

They can pass in very small amounts

Channel proteins

forms a tunnel or pore though the membrane; allows water or small polar molecules to pass

Transport proteins

binds to a molecule and changes its shape to move across the membrane

Cell Wall

occurs in plants, fungi, bacteria along with archaea

• keeps things outside the cell

• prevents osmotic lysis ( cells swelling and bursting)

Concentration Gradient

When a molecule is more concentrated on one side of the plasma membrane

Molecules naturally…

spread out towards areas of lower concentration until they are evenly distributed

Passive transport

The movement of molecules towards areas of lower concentration until they are evenly distributed

• uses no energy

Simple diffusion

When molecules move directly through the phospholipid bilayer without transport proteins

Facilitated diffusion

molecules go through the phospholipid bilayer with proteins

• used for large polar molecules

Active transport

When molecules move against the gradient which requires energy,

supplied by ATP

Vesicle

a small, fluid filled sac enclosed by a lipid bilayer

Endocytosis

When the plasma membrane folds inward and encloses around a large material, forming a vesicle inside the cell

Exocytosis

The vesicle containing material comes close to the plasma membrane and releases the material

Aquaporins

specialized channel proteins that allow large quantities of water to cross the membrane rapidly

Membrane polarization

the polarization of different sides of the membrane

Osmosis

The passive movement of water across a selectively permeable membrane

Water will always move from…

a area of higher water potential to the area of low water potential

OR

a place with more solute concentration to a place with less solute concentration

Hypotonic

Environment with less solute outside the cell; water moves into the cell

Hypertonic

environment with more solute outside the cell; water moves out

Isotonic

equal concentration both in and out the cell; water moves both ways

Osmoregulation

helps maintain homeostasis

Finding water potenttial

water potential = pressure potential + solute potential

solute potential

-iCRT

i in -iCRT

ionization constant/ sugar=1, salt =2

C in -iCRT

molar concentration mol/L

R in -iCRT

pressure constant (always 0.0831)

T in -iCRT

temp measured in kelvin

Kelvin = celcius temp +273.15

Electrochemical Gradient

A combination of a concentration gradient (difference in amount) and a electrical gradient (difference in charge)

Sodium-Potassium Pump

membrane protein that uses ATP to actively transport sodium ions and potassium against their concentration gradient

• 3 sodiums for every 2 potassiums

• makes outside more positive and inside more negative

ATPase

an enzyme that breaks down ATP which results in an energy release that can be used for cellular processes

Cell compartmentalization

the separation of cellular processes into distinct areas within a cell

Eukaryotic cells

contain a membrane bound nucleus and complex membrane bound organelles

Prokaryotic cells

lack a true nucleus and typically lack membrane bound organelles

Endosymbiosis

evolutionary process that allowed a free living organism to live inside a larger cell which form a close and dependent relationship

ex of evidence: mitochondria and chloroplast have a double membrane