week 1 & 2 quiz Flashcards
chapter 5 & 7
What structure is selectively permeable?
the plasma membrane: it allow some substances to cross it more easily than others
what are transport proteins responsible for?
controlling passage across cellular membranes
describe how the phospholipid bilayer is amphipathic
the hydrophobic tails of the phospholipids are sheltered inside the membrane, while the hydrophilic heads are exposed to water on either side
how does the cell demonstrate SA:V?
cell membrane-> SA of cells
interior (cytoplasm, organelles,etc.) -> volume
function of cell surface membranes?
-transport ***
-enzymatic activity
-signal transduction
-cell-cell recognition
-intercellular joining
-attachment to cytoskeleton & extracellular matrix
what can get through w/o help?
small, non-polar or hydrophobic or lipid soluble
what needs ATP to get through
large, polar, hydrophilic or water soluble, or charged (Ca2+, H+, Na+, K+)
what do transport proteins do?
allow charge molecules through
what are aquaporins?
channel proteins that greatly facilitate the passage of water molecules
what is diffusion?
the tendency for molecules to spread out, or down concentration gradient until it reaches dynamic equilibrium
what is passive transport?
simple diffusion of substance across membrane w/o help
what is osmosis?
diffusion of water from low to high solute concentration
H20 moves in a direction so as to dilute the concentrated side
what is a isotonic solution
solute concentration is the same as that inside the cell; no net water movement across the plasma membrane
what is a hypertonic solution?
solute concentration is greater than that inside the cell; cell loses water
what is a hypotonic solution?
solute concentration is less than that inside the cell; cell gains water
cells without cell walls?
shrivel in hypertonic and lyse in hypotonic
cells with cell walls?
hypotonic- turgid (normal)
isotonic-flaccid
hypertonic- plasmolyzed
what is osmoregulation?
control of solute concentrations & water balance; is a necessary adaptation for life in various environments
example: freshwater unicellular paramecium that uses contractile vacuole to get rid of water
what is facilitated diffusion?
transport proteins speed the passive movement of of charged molecules across the plasma membrane, ex: channel protein, carrier protein
what is active transport?
energy received, usually in the form of ATP hydrolysis, ex: sodium-potassium pump-> 3 Na+ move outside and bind to protein, 2 K+ move in to create gradient
what is membrane potential?
voltage across a membrane created by differences in the distribution of positive and negative ions across a membrane inside of cell is more negative than outside due to Na+K+ pump
what is a electrogenic pump?
generates a difference in voltage across membrane; the main pump for plants is the proton pump which transports H+ ions out of the cell; helps to store energy for cellular work
what is cotransport?
2 substances move at the same time, symporter= same direction; ex: plants -> H+/sucrose cotransporter
how to find SA:V ratio?
SA= lengthxwidthx# of sides
volume= lengthxwidthxheight
what are the macromolecules?
-carbohydrates
-proteins-nucleic acids
-lipids
what are polymers?
made up of small, repeating monomers; carbs, proteins, & nucleic acids are polymers
what are the complex sugars?
starch, glycogen(storage), cellulose( most abundant bio molecule; structural; cells walls), chitin (structure)
what is needed to make or break a polymer?
enzymes
what is the dehydration reaction?
2 monomers bond through loss of water molecule to make polymer
what is hydrolysis?
breaks down polymer
what are simple sugars?
monosaccharides: glucose, fructose, maltose
what are disaccharides?
2 monos, sucrose(glucose & fructose)
what are polysaccharides?
complex sugars: storage & structural sugars
what is starch?
major storage carb of glucose; found in roots & seeds of plants
what are the storage carbohydrates?
-glycogen in animals
-starch in plants
what is cellulose?
structural carb; major components of cell walls; most abundant on earth; is a polymer of glucose
what is chitin?
structural carb; found in insect skeletons
what are lipids?
hydrophobic & NOT composed of monomers; consist mostly of hydrocarbons, and most important types: fats, phospholipids, & steroids
the unfiying feature of lipids is that they mix poorly with water
what are fats constructed of?
1 glycerol & 3 fatty acids
what are saturated fats?
only one carbon bond, max hydrogen molecules; animal fat, solid at room temp; molecule is straight, so it can pack more tightly together so its solid; cardiovascular disease caused by diet rich in saturated fats
what are unsaturated fats?
less hydrogen, one carbon-carbon bond, liquid oils at room temp; cis double bond causes molecules to bend in curved shape; plant & fish fats
what is hydrogenation?
adding hydrogen to unsaturated fats to convert to sat. fats ; food companies do it, but its banned; it causes trans fats which is even worse for health
what is LDL
bad cholesterol
what is HDL
good cholesterol
parts of a phospholipid?
head-> choline, phosphate, and glycol
two fatty acid tails
what is surrounding charged molecules?
halo of water which makes it hydrophobic
types of proteins
-enzymatic-> selective attention of chemicals
-storage-> stores amino acids
-defensive-> protects against diseases
-transport-> moves substances
-hormonal-> coordination of one’s activities
-contractile & motor-> movement; ex: actin & myosin
-receptor-> response of cell to chemical stimuli
-structural-> support
what are amino acids?
organic molecules with amino acid & carboxyl groups
what are R groups?
functional group of each amino acid; hydrophobic R groups-> carbon & hydrogen; hydrophilic R groups-> electric charged and polar
how is a protein?
it comes in 4 structures
1) structure & function
2) how its folded
3) represents the 3-d structure
4) hemoglobin-> each subunit has atom of iron
what is sickle cell disease?
mutation of Heme subunit
