biology test

the signaling molecule

the molecule to which the receptor binds  -may be on the plasma membrane or within the cell

the events within the cell that occur in response to a signal

molecules on the surface of one cell are recognized by receptors on the adjacent cell

signal released from a cell has an effect on neighboring cells

hormonesreleased from a cell affect other cells throughout the body

nervecells release the signal (neurotransmitter)which binds to receptors on nearby cells

acommon way to change the activity of a protein.

an enzyme that adds a phosphate to a protein

an enzyme that removes a phosphate from a protein

receptor – located on the plasma membrane to bind a ligand outside the cell

ion channel that opens in response to a ligand

– receptor is an enzyme that is activated by the ligand

a G-protein (bound to GTP) assists in transmitting the signal

– receptors bound to G proteins

activatesan effector protein (usually an enzyme)

generates the cellular response to the original signal

have a nonpolar, lipid-soluble structure usuallyaffect regulation of gene expression

proteins are used by cells to distinguish “self” from “non-self”

are commonly used as tissue-specific markers

createsheets of cells

connect the cytoskeletons of adjacent cells

permit small molecules to pass between cells

in animal cells

in plant cells

inserted in the lipid bilayer

arranged in a bilayer

a3-carbon polyalcohol acting as a backbone for the phospholipid

attached to the glycerol

anchored to a phospholipid in one layer of the membrane  -possess nonpolar regions that are inserted in the lipid bilayer  -are free to move throughout one layer of the bilayer

span the lipid bilayer (transmembrane proteins)  -nonpolar regions of the protein are embedded in the interior of the bilayer  -polar regions of the protein protrude from both sides of the bilayer

regionof the protein containing hydrophobic amino acids

interior is polar and allows water and small polar molecules to pass through the membrane

is movement of molecules through the membrane in which  -no energy is required  -molecules move in response to a

ismovement of molecules from high concentration to low concentration

integral membrane proteins allow the cell to be selective about what passes through the membrane.

have a polar interior allowing polar molecules to pass through.

bind to a specific molecule to facilitate its passage.

allow the passage of ions (charged atoms or molecules) which are associated with water

are opened or closed in response to a stimulus

is movement of a molecule from high to low concentration with the help of a carrier protein.

is the movement of water from an area of high to low concentration of water

has a higher solute concentration

has a lower solute concentration

aquaporins

extrusion

Isosmotic regulation

turgorpressure

requiresenergy – ATP is used directly or indirectly to fuel active transport

– move one molecule at a time

move two molecules in the same direction

movetwo molecules in opposite directions

an active transport mechanism  -uses an antiporter to move 3 Na+ out of the cell and 2 K+ into the cell

uses the energy released when a molecule moves by diffusion to supply energy to active transport of a different molecule  -a symporter is used

– movement of substances into the cell

movement of materials out of the cell

thecell takes in only fluid

specificmolecules are taken in after they bind to a receptor

as a cell increases in size, the volume increases 10x faster than the surface area

canresolve structures that are 200nm apart

canresolve structures that are 0.2nm apart

canresolve structures to the atomic size.

lacka membrane-bound nucleus.

cellwalls lack peptidoglycan

•  nucleosomes
• chromatin

thesite of protein synthesis in the cell

synthesis of proteins to be secreted, sent to lysosomes or plasma membrane

-relatively few ribosomes attached  -functions:  -synthesis of membrane lipids  -calcium storage  -detoxification of foreign substances

flattened stacks of interconnected membranes  -packaging and distribution of materials to different parts of the cell

destroycells or foreign matter that the cell has engulfed by phagocytosis

membrane-bound structures with various functions depending on the cell type

contain oxidative enzymes and catalase

organelles present in cells of plants and some other eukaryotes  -contain chlorophyll for photosynthesis

are membranous sacs within the inner membrane

are stacks of thylakoids

proposedthat eukaryotic organelles evolved through a symbiotic relationship

9pairs of microtubules surrounded by 2 central microtubules

composed of glycoproteins and fibrous proteins such as collagen  -connected to the cytoplasm via integrin proteins present in the plasma membrane