UNIT 2 AP BIO TEST

Solvent

Liquid that dissolved substance, usually water

Solute

The substance dissolved in water, EX: salt

What are proteins made of?

Amino acids (Amino group, R group, carboxyl group)

Unicellular organisms

single celled organism EX: bacteria, yeast

Multicellular Organisms

Made up of many cells EX: protists, plants, fungi

ALL CELLS HAVE?

• Cell membrane

• Cytoplasm

• Ribosome

• DNA

Prokaryotes

• No nucleus

• DNA is in cytoplasm

very small compared to other organisms

Eukaryotes

• DNA in nucleus

• single and multicellular

• Specialized cells (to do different functions)

• Organelles!!

SA:V ratio

As objects get larger:

• its surface area and volume increases

• Volume increases WAY FASTER than surface area

This means that the cell has to adapt to increase surface area

because more surface area = more efficiency

How do cells increase surface area?

• cells stay small and have weird shapes (EX: neurons-long and thin)

• have highly folded internal membranes (EX: inner membrane of mitochondria)

• highly folded organs (EX: Villi of intestines)

How does cell size affect heat transfer?

• Large organisms have low SA:V = low rate of heat exchange

• Small organisms have high SA:V = high rate of heat exchange

  -Small organisms have faster metabolism in order to generate enough heat to stay warm

Vesicles

• help transport materials and recycle waste materials

• fuse with other organisms (organelles are not isolated, many connected by vesicles)

Nucleus

• Stores DNA

• makes ribosomes

• Has pores to communicate from the nucleus to the cell and back

• Proteins made in cytoplasm go through pores to access DNA

Endoplasmic reticulum (Rough ER)

• Has ribosomes, which are small, round organelles whose function it is to make proteins.

• syntheses proteins that will later leave the cell

Endoplasmic reticulum (Smooth ER)

• lacks ribosomes

• predominant in cells that export lipids like steroids hormones

• It synthesizes lipids, phospholipids as in plasma membranes, and steroids

Golgi apparatus

a factory in which proteins received from the ER are further processed and sorted for transport to their eventual destinations: lysosomes, the plasma membrane, or secretion.

Lysosomes

• the digestive system of the cell

• vesicles derived from golgi

• contains enzymes to degrade damaged and unneeded macromolecules

• cell death

What organelles are involved in energy?

• Mitochondria

• Chloroplast

Mitochondria

• Harnesses energy for cell

• generate most of the chemical energy needed to power the cell's biochemical reactions

• generates energy (ATP)

Two membranes

• inner membrane (highly folded = <SA

• outer membrane

Chloroplast

• Captures energy from sun to synthesis simple sugars.

• photosynthesis consumes carbon dioxide, releases oxygen as a waste product

• double membrane

Why does the mitochondria and Chloroplast have double membranes?

ENDOSYMBIOSIS

They originally were free living bacteria, they were engulfed by cell and evolved to become the Mito- and Chloro- in Eukaryotic cells

Evidence:

• contains own DNA not in nucleus

• resembles bacteria

• contains ribosomes

• replicate on their own

• double membrane

Nucleolus

The nucleolus is a spherical structure found in the cell's nucleus whose primary function is to produce and assemble the cell's ribosomes. The nucleolus is also where ribosomal RNA genes are transcribed.

DNA: slightly coiled called chromatin

really condensed DNA: chromosomes

Cytoplasm

gelatinous liquid that most of everything floats in

Ribosomes (and golgi apparatus)

• can attach to ER

• makes proteins

• emerges from ER in vesicles—golgi apparatus receives proteins from them- the protein is modified there in there to 3d shapes/ other molecules added

vacuoles and contractiles vacuoles

Vacuoles:

• stores material like in plant cells, stores water in central vacuole

Contractile Vacuole:

• controls the intracellular water balance by accumulating and expelling excess water out of the cell, allowing cells to survive under hypotonic stress

chlorophyll

• Chlorophyll is the natural compound present in green plants that gives them their color.

• are in chloroplast (energy from sun)

cytoskeleton

The cytoskeleton is a structure that helps cells maintain their shape and internal organization

cell wall

• plants have this to give them cell shape and provides protection

• made of complex carbohydrates (cellulose)

Flagella

• bacteria/sperm has this

• tail that helps them move

Cilia

• small hairs that moves debri up and out of airways

Cell membrane

• maintains homeostasis in cell

• flexible

• effective gatekeeper

• selectively permeable

Phospholipids

• glycerol

• phosphate group/head (polar) = hydrophilic

• 2 fatty acid tails (nonpolar) = hydrophobic

this makes up the cell membrane with the phosphate head on the outside and the 2 fatty acid tails on the inside

Integral membrane proteins:

IN CELL MEMBRANE

• span entire membrane

• hydrophilic interior (enzymes)

• hydrophilic exterior (receptor)

EX: Channel and carrier proteins are two types of integral transmembrane proteins

Peripheral membrane proteins:

IN CELL MEMBRANE

• either internal or external side of membrane

• temporarily associated with bilayer

Fluid Mosaic Model

in the cell membrane everything is moving around constantly

cholesterol

(steroid =lipid)

• hydrophilic and hydrophobic regions

• aids in fluidity of membrane and stability

High temps: cholesterol decreases membrane fluidity = more stable, interacting with phospholipid fatty acid tails reducing mobility

Low temps: Cholesterol increases membrane fluidity by preventing phospholipids from packing tightly with other phospholipids

Carbohydrates

• usually attached by covalent bonds

• EX covalently bonded to lipid = Glycolipid

• EX covalently bonded to protein = Glycoprotein

• acts as receptors for chemical signals or cell recognition

IN CELL MEMBRANE

Plasmodesmata

openings in cell wall (really cool word ig)

allows for exchange of ions and signaling molecules

what molecules can and cannot cross the cell membrane?

can:

• nonpolar, uncharged, small molecules

• EX: N2, Co2 O2

Cannot:

• Polar, charged, and large molecules

• EX: proteins, polysaccharides

Concentration gradient

passive transport is the net movement of molecules from one region to another, concentration gradient is the DIFFERENCE in concentration of molecules

usually from high to low

Diffusion

• net movement of molecules from one region to another

• no input of energy

• molecules are small, nonpolar, uncharged

• EX: oxygen diffuses into cell

During passive diffusion, a molecule simply dissolves in the phospholipid bilayer, diffuses across it, and then dissolves in the aqueous solution at the other side of the membrane.

Facilitated diffusion

diffusion across a cell membrane through a transport protein

• H—L until equilibrium

• no input of energy

• molecules that are too large, charged or polar that cannot diffuse normally

  TWO TYPES

• channel protein -opening through membrane

• carrier protein

• binds to molecules, protein changes shape, passes molecule through

Aquaporins

• water channels (small amount can diffuse across membrane but most through this channel)

Na+ and K+ channels

• creates electrical signal (action potential) in neurons

• different amounts of electric charge then outside of cell

• =cell membrane potential

• Action potential: how signals are sent to the brain and rest of nervous system

Osmosis

• diffusion of water

• high to low until equillibrium

• no input of energy

Osmotic pressure

the tendency of water to move from one solution to another by osmosis

Hypertonic

higher solute concentration than another solution (ex: more sugar)

if a cell is in a hypertonic solution the cell shrivels up

Hypotonic

less solute concentration than another solution OR more water than a hypertonic solution

if a cell is in a hypotonic solution the cell lyses/bursts

Isotonic

same solute concentration as a cell/other solution

Molarity

concentration of solute in solvent (mol/L)

percent change in formula

Turgor pressure

force exerted by water pressing against a cell wall

osmosis will continue until turgor pressure increases to level able to stop it

what affects movement of H2O?

• Solute concentration

• pressure

• gravity

• temperature

Water potential

water moves from high water potential to low water potential OR low osmolarity — high osmolarity

Active transport

• low to high concentration

• ATP used- energy

• protein carrier - to move molecules against concentration gradient

  EX: sodium-potassium pump

• maintains the electrochemical gradients of neurons

• uses ATP

• 3Na+ out of cell, K+ into cell

• in cell membrane of neurons

ATP is used to alter the shape of the pump protein

Endocytosis

process that brings large substances into cell using a vesicle

Exocytosis

process that releases large substances out of cell

vesicle with substance fuses with cell membrane, contents released outside of cell

Junction

tight junction:

• proteins wrap around the cell membrane made of multiple cells and holds them tightly to prevent leakage

• EX: stomach cells, bladder cells

“lose” junction

• proteins stick out of cell membrane, connects to other cell membrane to hold them together

• EX: skin cells, heart cells, muscle cells, ect

communication with other cells

embedded in cell membrane are variety of different protein receptor that combine to signaling molecules that are secreted into extracellular space or blood