ap bio u2

def more info than what's necessary for the ap test

cell theory

1. all organisms are made up of cells
2. the cell is the fundamental unit of life
3. cells come from pre-existing cells

what is a cell? (5 requirements)

cell = smallest unit we define as living

=> has cell membrane
=> has cytoplasm
=> store, use, and transmit genetic info
=> ribosomes
=> metabolism

metabolism

set of chemical reactions used to maintain homeostasis by transferring energy -> build/breaks molecules

anabolism

builds up from smaller units -> REQUIRES ATP

catabolism

breaks molecules down -> RELEASE energy in form of ATP/heat

cell membrane

lipid bilayer

encloses the cell and controls the movement of substances in and out (helps maintain homeostasis)

homeostasis

active maintenance of stable internal conditions

(cell requires energy to maintain it)

cytoplasm

jelly-like substance inside the cell

where organelles are suspended and where cellular processes occur

ribosome

site of RNA synthesis (made up of RNA & protein)

nucleus/nuclear envelope

organelle with a double membrane (nuclear envelope) and nuclear pores

houses DNA, RNA synthesis, ribosome assembly

endoplasmic reticulum (ER)

outer membrane of nuclear envelope

rough ER

covered with ribosomes

where proteins for transport are assembled

smooth ER

no ribosomes

makes lipids, metabolizing carbs

golgi apparatus

flat disk shaped membranes

modifies, sorts, packages proteins

vesicle

a small cavity or sac that contains materials in a eukaryotic cell (absorbs toxic ones and transports others)

lysosome

vesicle from golgi that contains digestive enzymes

breaks down old macromolecules for reuse in the cell

mitochondria

double membrane

site of cellular respiration; produces ATP (energy)

chloroplast

stacks of thylakoids (contains chlorophyll) connected by membrane bridge

site of photosynthesis

cell wall

rigid outer layer found in plant cells, fungi, and some prokaryotes

maintains cell shape (structural support/protection)

cytoskeleton

network of protein fibers

structural support, facilitates cell movement, and organizes organelles

vacuole

membrane-bound sac that DOESN'T fuse with others

stores nutrients & other waste products

flagella

whiplike tails found in one-celled organisms to aid in movement

cilia

extends from membrane and helps with motion across the membrane surface

central dogma of biology

DNA provides info for RNA -> RNA synthesizes proteins

ATP

nucleotide that provides energy

diffusion

passive movement of molecules from high -> low

driven by the random motion of particles

properties of prokaryotic cells (5)

-small
-no nucleus
-few organelles
-unicellular
-bacteria/archaea

properties of eukaryotic cells (4)

-large/complex
-has nucleus
-uni OR multicellular
-includes plants & animals

properties of BOTH euk and prok

has: DNA, cell membrane, cytoplasm, flagella/cilia, ribosomes

what do eukaryotic cells mainly rely on for organization?!

the cytoskeleton (as opposed to the cell walls, which some don't have)

types of prokaryotic cells

bacteria and archaea cells

archaea

tolerates/requires environmental extremes (heat/acidity)

plasmids

small rings of DNA that can replicate separately

inside bacteria

which increases faster, SA or V

volume

why does diffusion limit prokaryote size? how do they deal?

only works over short distances BUT internal membranes make larger sizes viable (more SA provided)

bulk flow

the movement of a fluid driven by pressure

whys circulatory system important??

provides oxygen w out using diffusion (more efficient way to transport oxygen to cells)

different phospholipid forms

micelle and liposome

micelle

small single-layered amphipathic molecules

liposome

larger spherical vesicles with a lipid bilayer for delivering substances into cells

lipid rafts

lipids assembled in a defined patch in the cell membrane

lipid flip-flop

spontaneous transfer of a lipid between layers (very rare)

types of proteins in cell membrane

transport, receptor, anchor

transport proteins

helps move substances across a cell membrane

receptor proteins

senses surroundings and receives messages, transmits info

anchor proteins + two types?

maintains cell structure/shape by attaching to other proteins

(integral membrane & peripheral)

integral membrane proteins

permanent (can't be moved) usually transmembrane

peripheral membrane proteins

temporarily associated with weak noncovalent attractions

gylcolipid/glycoprotein

carb cov. attached to lipid/protein

mosaic model of cell membrane

lipid bilayer is fluid & made up of a variety of molecules

simple diffusion

diffuse directly into cell membrane w out assistance as a result of concentration differences

ONLY HIGH -> LOW

facilitated diffusion + types of transport proteins

diffusion across cell membrane through transport protein (transmembrane protein that spans entire membrane)

channel & carrier proteins

carrier protein

binds to and transports molecules

channel protein

provides opening where specific molecules can pass through (sometimes have "gates" that respond to a signal)

aquaporins

channel proteins that facilitate the passage of water

ways cells take in molecules

passive & active transport

passive transport

Requires NO energy

movement of molecules from high to low concentration

moves with the concentration gradient

active transport

REQUIRES energy

movement from low -> high


concentration moves against concentration gradient

primary active transport

uses energy from ATP directly (energy stored in bonds)

secondary active transport

uses PE from electrochemical gradient generated by primary active transport

antiporters

type of active transport that moves two molecules in opposite directions

symporters

carry two substances across the membrane in the same direction

how r large molecules moved in/out of the cell?!

endocytosis & exocytosis (+ phagocytosis)

endocytosis

taking in molecules from extracellular space thru the formation of a vesicle

exocytosis

vesicle fuses with cell membrane, releasing its contents to the extracellular space

phagocytosis

form of endocytosis where microorganisms/dead cells/large particles are "absorbed" into the cell -> digested in lysosomes

ONLY EUKARYOTIC

osmosis

diffusion of water across a selectively permeable membrane (from low solute conc -> high solute conc)

osmosregulation aka whys osmosis important/necessary?!

osmoregulation is a form of homeostasis; chemical functions of cells/organisms depend on amt of water in a cell (eg. cell membranes which act as selectively permeable membranes)

osmotic pressure

the amount of force applied to a solution that prevents solvent from moving across a semipermeable membrane

hydrostatic pressure

pressure exerted by any fluid due to gravity

tonicity

osmotic pressure & direction of water movement (how strongly water is pulled from one sol to another)

hypotonic solution

cell gains water
solution solute concentration < cell solute concentration

hypertonic solution

cell loses water

cell solute concentration > solution solute concentration

isotonic solution

cell neither gains nor loses water; a solution whose solute concentration is equal to the solute concentration inside a cell

turgor, what's lack of turgor called?

when the cell walls push outward due to water pressure increases inside the cell

(caused by water/turgor pressure, lack of turgor = wilting)

water potential - what does low wp signify?

measure of how likely water is to move in and out of cells

(low wp = water has a low force driving it to move from one area to another & vice versa)

equation for water potential

water potential = solute potential + pressure potential

pressure potential

THE SOLUTION’s PRESSURE POTENTIAL IS USUALLY 0; physical pressure increases water potential

solute potential

ALWAYS NEGATIVE because the greater the concentration of a solute, the lower the water potential

(dissolution of solutes uses up available PE)

solute potential = iCRT -> ionization constant?

ionization constant depends on number of ions involves (eg. NaCl has i = 2)

when are the various potentials = 0?

PURE WATER: water, solute, pressure potential = 0 OPEN CONTAINER: solution’s pressure potential = 0

whats it mean when a cell keeps a constant volume

solute potential = pressure potential

osmoregulation - what's it do?

regulation of osmotic pressure inside cells & organisms

keeps internal fluids from becoming too concentrated

(form of homeostasis)

osmoconformers

organisms that match their internal osmotic pressure to that of their surrounding environment

DOESN'T spend too much energy

osmoregulators

actively regulates their internal osmotic pressure to maintain homeostasis (regardless of external conditions)

DOES expend significant energy pumping ions across cells to regulate enter/departure

what's it mean to say euks are in dynamic continuity

maintain stability & function thru various continuous exchanges despite constant internal/external changes

multicellularity

being composed of many cells

-> allows for many diff functions & possibilities

symbiosis & symbiont

close relationship & interaction btwn two organisms

symbiont: organism that lives in closely evolved associate w other species

the two eukaryotic cell origin theories

1. endosymbiosis

ONE SINGLE EVENT in which a prokaryotic cell engulfed smaller prok cells (eg. proteobacteria -> mitochondria)

2. symbiogenesis

GRADUALLY evolved through series of endosymbiotic events integrating different prokaryotic organisms

cytosol

liquid part of cytoplasm

enzyme

a protein that acts as a catalyst

cellular respiration

glucose + oxygen → CO2 + water + ENERGY

converts the energy stored in organic molecules to ATP

photosynthesis

CO2 + water + ENERGY → glucose + oxygen

uses sunlight energy to synthesize carbs

protist

euk that isnt plant animal or fungus

endosymbiosis

one organism lives within the other