ap bio unit 2

free ribosomes

make proteins that work in cytoplasm, freely in cytosol

bound ribosomes

attached to rER, make secretory proteins

example of secretory protein

insulin

2 functions of rER

1. produces proteins for export out of cell & uses transport vesicles for that

2. creates phospholipid and adds it to its own membrane

functions of sER: synthesis of (4)

oils, phospholipid, steroids, sex hormones

functions of sER; detoxification drugs & poison in ____ cells

liver

function of sER: stores ____ions, important for ______ ______

calcium, muscle contraction

golgi function

correct folding & transporting of newly synthesized proteins and packing for protein traffic

lysosomes contain_____ ____

hydrolytic enzymes

what do hydrolytic enzymes do

1. digest & recycle macromolecules

2. cell apoptosis (cell death)

3. clean up broken down cell organelles

Tay sachs

lacks a functional hydrolytic enzyme (that normally breaks down fatty substance) that results in a buildup of toxic levels in brain and spinal cord, that affects the function of nerve cells

apoptosis

programmed cell death, release hydrolytic enzyme into the cytosol to kill the cell

endomembrane pathway for secretory proteins

1. rER - synthesis of secretory protein takes place here

2. transport vesicle that comes from rER and goes to golgi

3. golgi apparatus that sorts the protein vesicle to be exported

4. transport vesicle

5. cell membrane

6. exocytosis

endomembrane pathway for lysosome

1. rER - synthesis of protein

2. transport vesicle

3. golgi apparatus

4. lysosome

note that the “synthesis of protein” would be the hydrolytic enzyme protein

volume determines the amount of ______ in a cell

metabolism

surface area of plasma membrane must be ____ enough to adequately exchange materials

large

___cells typically have a higher ____ more ____exchange of materials with environment

smaller, surface area to volume ratio, efficient

the bigger the surface area: volume ratio

the more efficient the cell is

small polar molecules

can pass through, but it is a very slow process

small nonpolar molecules

easily pass through

large polar molecules

needs transport proteins

large nonpolar molecules

can pass through but is slow

sugars and charged ions DO NOT

pass through the membrane easily (need transport proteins)

at warm temp (37 c) steroid AT HIGH TEMP

provides structure to the cell, restrains movement of phospholipid, increases rigidness, decreases fluidity

at LOWER temp (colder), steroids

maintain phospholipid fluidity by preventing tight packing, increases fluidity and decreases rigidity

peripheral proteins

attached to the surface of the membrane

integral protein

inside the phospholipid bilayer

an integral protein that spans the entire bilayer is called a

transmembrane protein

The hydrophobic regions of an integral protein consist of one or more stretches of nonpolar amino acids, often coiled into

alpha helixes

transport proteins allow the passage of ____ or _____ substances accross membrane

ions, hydrophilic

what protein is it called that has its own hydrophilic channel

channel proteins

which channel protein facilitates large amounts of water

aquaporin

transport proteins are also called

membrane proteins

transport/membrane proteins are:

transport: channel proteins, carrier proteins

membrane: peripheral, transmembrane, integral

cells divide to

increase efficiency

inner membrane of mitochondria is folded because we need to _________so you can ___________

increase the surface area so you can increase efficiency

microvilli on intestinal lining

higher SA: V ratio to optimize absorption

protein folding dictates what

what parts are exposed to water, whether it should sit on membrane.

the two ends of the transmembrane protein is

hydrophilic and polar (n terminus and c terminus)

aquaporin is a _____protein that forms _____ _____ ______ which allows water to _____ ______

channel, water selective channels, diffuse faster

carrier proteins

change shap, by 1) binding to molecule, 2) confirmation change to protein

you do NOT need ___ to change shape

energy

nonpolar key words

lipid, soluble & fat soluble

polar key words

water soluble, Na+

what is simple diffusion

small nonpolar molecules , hydrophobic molecules like hydrocarbons CAN PASS THRU MEMBRANE EASILY

a transport protein is specific to what it moves. example

glucose proteins only transport glucose molecules

facillitated diffusion

needs help from membrane/transport proteins; large polar molecules (water), ions,

both simple and facilitated diffusion go down ___ and don’t need ___

concentration gradient from high to low, ATP

passive transport primarily role

import of materials & export of waste

large quantities of water can pass thru

aquaporin channels

charged ions require what type of transport protein

channel proteins

active transport

against conc gradient from low to high * REQUIRES ENERGY

active transport requires energy and through a process

ATP hydrolysis

what kind of amino acids will be the ones that make up the peripheral proteins:

polar molecules

: Can water freely diffuse across the membrane

no, water is polar and needs aquaporin

what does na/k pump do

uses atp to pump 3 na out of cell and 2 K+ into cell

what happens if sodium/potassium pump stops working

does not maintains a membrane potential

• na+ increase inside the cell (no longer being pumped out)

• K+ increase outside of the cell (no longer pumped back in)

why does the pump need atp

it moves na+ and k+ against their conc gradients

what happens if na isnt working

buildup in cell (no more removing it)

what happens if sodium channel is blocked

na movement across membrane decreases

if pump malfunctions

membrane potential is lost & neural transmission cannot happen. there needs to be a voltage difference (electricity) for neurons to fire/action potential

proton pump

push protons across membrane

atp production in 2

cellular respiration * photosynthesis

proton pump can only transport H+ from [low] to [high], it is a

one-way

3 processes that need atp

bulk transport, endocytosis, exocytosis

bulk transport

Large molecules, such as polysaccharides, lipids and proteins, cross the membrane via transport vesicles

bulk transport has two types of transport

endocytosis and exocytosis

endo, phagocytosis, pinocytosis

in: cells engulfs a vacuole, cell creates vesicle around fluid

receptor mediated endocytosis

receptor – protein on the surface of the membrane bind to ligands, ligand – anything can be a ligand) to bring in molecules, need to bind with them in order to bring them in  

exocytosis

Secretory cells: once insulin is produced, the vesicle will migrate to cell membrane, fuse with it, become part of it, and then release the protein out. 

example of exocytosis

neurotransmitter

plant: hypertonic

plasmolysis

plant: isotonic

flaccid

plant: hypotonic

turgid

animal: hypertonicity

shriveled

animal: isotonic

normal

animal: hypotonic

lysed

paramecium contractile vacuole in hypotonic medium

it will pump out water regularly so that it doesn’t burst

paramecium contractile vacuole in ocean water

ocean water is a hypertonic solution, so the vacuole will pump at a slower rate, and the contractile vacuole will conserve its water

water potential

tendency for water to move by osmosis

water potential of pure water is given the

value

zero

In an open system, pressure potential is

zero

solute potential determined by

solute concentration

where will water move?

• high to low concentration of WATER

• low to high concentration of SALT

• high to low concentration of pressure

• from a hypotonic solution to a hypertonic solution

• low osmolarity to high osmolarity

• diluted solution to concentrated solution
  
  

calculate solute potential with

iCRT (rmbr i=ionization, C=molar concentration, r=0.0831, T=273+C)

sucrose ionization constant

1

Nacl ionization constant

2

adding solute to water lowers

solute potential (more negative)

hypertonic solutions have ___ solute potentials

negative

osmolarity

measure of solute conc

aquaporin channels found in what organ

kidney

The rate of metabolism of a cell is a function of its ____ and why

mass/volume because a larger area needs enough energy to carry out its functions

The rate of material exchange is a function of its ____ and why

surface area because a larger area has more membrane/material movement needed

when a cell grows its volume ____ faster than its surface area

increases so SA: V ratio decreases therefore exchange of nutrients/waste become less efficient