cell theory

the cell is life's basic (smallest) unit of structure and function

compartments in cells are for...

more specialization

surface-area-to-volume-ratio

larger = more efficient, folds increase, smaller cells have higher

What happens as an organism increases in size?

its surface area to volume ratio decreases, affecting things like heat exchange (small organisms lose heat much faster)

What organisms have a cell wall?

prokaryotes, plants

What organisms have a membrane-bound organelle?

plants, animals

What organisms have a nucleus?

plants, animals

What organisms have ribosomes and plasma membranes?

all

What organisms have chloroplasts?

some prokaryotes (photosynthetic bacteria), plants

What organisms have vacuoles?

some prokaryotes (contractile), plants (central), animals (small)

What organisms have lysosomes?

animals

peripheral proteins

located on the inner or outer surface of the plasma membrane (e.g. digestive enzymes on the sides or attached to integral proteins)

integral proteins

firmly bound to plasma membrane (integral to it!), transport large molecules, amphipathic

transmembrane proteins

integral proteins that extend all the way through the membrane (from the outer surface to the inner)

adhesion proteins

plasma membrane protein functional group that forms junctions between adjacent cells

receptor proteins

plasma membrane protein functional group that serves as docking site for arrivals at cells (e.g. takes in hormones)

transport proteins

plasma membrane functional group that forms channels that selectively allow the passage of ions or molecules

cell surface markers

plasma membrane protein functional group exposed on the extracellular surface and plays a role in cell recognition and adhesion (e.g. glycoproteins, glycolipids)

carbohydrate side chains

attached to the surface of some proteins only on the outer surface of the membrane

70S ribosomes

in prokaryotes, smaller, free-floating

80S ribosomes

in eukaryotes, larger, free-floating or attached

glycosylation

adds glucose to a protein in secretory protein synthesis

calcium ions in the SER

necessary for muscle contraction (nerve signal sent to calcium ions which leak into cytosol which triggers contraction)

cis face

closest to the RER, takes in

medial face

middle face of the Golgi apparatus, modifies materials to chemically mark and sort and transport them with GLYCOPROTEINS

trans face

farthest from the RER, ships out

lumen

contains the acidic pH of the lysosome and hydrolytic enzymes

How are lysosomes formed?

made when vesicles with specific enzymes from the trans Golgi fuse with vesicles from endocytosis

microtubule organizing centers (MTOCs)

contain centrioles for centrosome formation and cell division

central vacuole

stores vital chemicals, cell metabolism waste, water (retains for Turgor pressure); crowds other organelles

contractile vacuoles

expel water from protists (hub expels while spokes collect)

peroxisomes

detoxify various substances by oxidizing / neutralizing them, produce hydrogen peroxide as a byproduct (enzymes inside must break down into oxygen and water), common in liver and kidney cells

microfilaments

made of actin monomers; help cell change shape / grow / shrink in cytokinesis, muscle contraction, pseudopodia extensions for cell movement

intermediate filaments

rope-like fibrous proteins; reinforcing rods for tensions and anchor organelles

microtubules

made of tubulin (globular proteins); elongate with tubulin pairs added or removed, anchor organelles, guide organelle movement in the cytoplasm, in flagella and cilia

Gram positive

no extra lipid membrane, less dangerous in bacteria (thicker peptidoglycan layer, purple)

Gram negative

outer lipid membrane, one side touches membrane and the other the lamella (extracellular matrix), more dangerous in bacteria (thin peptidoglycan layer, pink/red)

extracellular matrix

a sticky glycoprotein layer which holds cells together and uses proteins to regulate cell behavior in the plasma membrane

plasmodesmata

cell junction in plant cells, allows for small molecules and water to move between cells and cell communication

tight cell junction

binds cells into a leak proof sheet

anchoring cell junction

connects adjacent cells using cytoskeletal fibers

communicating cell junction

allows small molecules and water to move between cells

nonfacilitated diffusion

passive transport through the plasma membrane (must be small, nonpolar, noncharged, hydrophobic)

aquaporin

water-specific channels that help water quickly diffuse across the membrane (since it is polar, takes forever to get across otherwise)

substances that use facilitated diffusion

glucose, amino acids, atomic ions (Ca+, K+, Cl+, Na+), water

resting membrane potential

difference in charge between the inside and outside of the cell, determined by the concentration gradient of ions across the plasma membrane and the membrane permeability of each ion (e.g. Na+ and K+ in the sodium-potassium pump move down their gradients via channels, a separation of charge is created that makes resting potential)

equilibrium potential

the potential that would be generated by an ion if it were the only ion in the system (e.g. K+ in the sodium-potassium pump)

polarized membrane

created as ions move across the membrane (gives positive charge on one side and negative on the other, producing resting potential in living cells)

sodium-potassium pump

an active transport mechanism that consumes ATP to move 3 NA+ out and 2K+ in against their concentration gradients

tonicity

term used to describe osmotic gradients with solutions in a cell (e.g. hypertonic, hypotonic, isotonic)

isosmotic, hyperosmotic, hyposmotic

terms used to describe osmotic gradients when comparing two solutions, not necessarily in a cell

Does the same net movement occur no matter the solute kinds?

yes

Is the direction of osmosis determined by the total difference in solute concentration?

yes, water moves based on the TOTAL concentration of solutes combined, not individual solutes (e.g. seawater has many different solutes but loses water to a solution with a higher concentration of a single solute)

osmoregulation

how cells control water balance

When are exocytosis and endocytosis used?

for LARGE molecules

bulk flow

the one-way movement of fluids brought about by pressure (e.g. pumping of blood through a blood vessel or the movement of fluids in the xylem and phloem of plants)

xylem

the vascular tissue responsible for transporting water and dissolved minerals from the roots to the rest of the plant

phloem

the vascular tissue that carries organic nutrients (e.g. sugars) from photosynthetic areas of the plant to non-photosynthetic areas.

transpiration

water evaporates, creating a negative pressure that aids in bulk flow within xylem (water is pulled upward)

dialysis

diffusion of SOLUTES across a selectively permeable membrane (e.g. kidney dialysis filters blood using machines and concentration gradients)