week 1 & 2 quiz

Question 1

What structure is selectively permeable?

Answer 1

the plasma membrane: it allow some substances to cross it more easily than others

Question 2

what are transport proteins responsible for?

Answer 2

controlling passage across cellular membranes

Question 3

describe how the phospholipid bilayer is amphipathic

Answer 3

the hydrophobic tails of the phospholipids are sheltered inside the membrane, while the hydrophilic heads are exposed to water on either side

Question 4

how does the cell demonstrate SA:V?

Answer 4

cell membrane-> SA of cells
interior (cytoplasm, organelles,etc.) -> volume

Question 5

function of cell surface membranes?

Answer 5

-transport ***
-enzymatic activity
-signal transduction
-cell-cell recognition
-intercellular joining
-attachment to cytoskeleton & extracellular matrix

Question 6

what can get through w/o help?

Answer 6

small, non-polar or hydrophobic or lipid soluble

Question 7

what needs ATP to get through

Answer 7

large, polar, hydrophilic or water soluble, or charged (Ca2+, H+, Na+, K+)

Question 8

what do transport proteins do?

Answer 8

allow charge molecules through

Question 9

what are aquaporins?

Answer 9

channel proteins that greatly facilitate the passage of water molecules

Question 10

what is diffusion?

Answer 10

the tendency for molecules to spread out, or down concentration gradient until it reaches dynamic equilibrium

Question 11

what is passive transport?

Answer 11

simple diffusion of substance across membrane w/o help

Question 12

what is osmosis?

Answer 12

diffusion of water from low to high solute concentration
H20 moves in a direction so as to dilute the concentrated side

Question 13

what is a isotonic solution

Answer 13

solute concentration is the same as that inside the cell; no net water movement across the plasma membrane

Question 14

what is a hypertonic solution?

Answer 14

solute concentration is greater than that inside the cell; cell loses water

Question 15

what is a hypotonic solution?

Answer 15

solute concentration is less than that inside the cell; cell gains water

Question 16

cells without cell walls?

Answer 16

shrivel in hypertonic and lyse in hypotonic

Question 17

cells with cell walls?

Answer 17

hypotonic- turgid (normal)
isotonic-flaccid
hypertonic- plasmolyzed

Question 18

what is osmoregulation?

Answer 18

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

Question 19

what is facilitated diffusion?

Answer 19

transport proteins speed the passive movement of of charged molecules across the plasma membrane, ex: channel protein, carrier protein

Question 20

what is active transport?

Answer 20

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

Question 21

what is membrane potential?

Answer 21

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

Question 22

what is a electrogenic pump?

Answer 22

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

Question 23

what is cotransport?

Answer 23

2 substances move at the same time, symporter= same direction; ex: plants -> H+/sucrose cotransporter

Question 24

how to find SA:V ratio?

Answer 24

SA= lengthxwidthx# of sides
volume= lengthxwidthxheight

Question 25

what are the macromolecules?

Answer 25

-carbohydrates -proteins-nucleic acids -lipids

Question 26

what are polymers?

Answer 26

made up of small, repeating monomers; carbs, proteins, & nucleic acids are polymers

Question 27

what are the complex sugars?

Answer 27

starch, glycogen(storage), cellulose( most abundant bio molecule; structural; cells walls), chitin (structure)

Question 28

what is needed to make or break a polymer?

Answer 28

enzymes

Question 29

what is the dehydration reaction?

Answer 29

2 monomers bond through loss of water molecule to make polymer

Question 30

what is hydrolysis?

Answer 30

breaks down polymer

Question 31

what are simple sugars?

Answer 31

monosaccharides: glucose, fructose, maltose

Question 32

what are disaccharides?

Answer 32

2 monos, sucrose(glucose & fructose)

Question 33

what are polysaccharides?

Answer 33

complex sugars: storage & structural sugars

Question 34

what is starch?

Answer 34

major storage carb of glucose; found in roots & seeds of plants

Question 35

what are the storage carbohydrates?

Answer 35

-glycogen in animals -starch in plants

Question 36

what is cellulose?

Answer 36

structural carb; major components of cell walls; most abundant on earth; is a polymer of glucose

Question 37

what is chitin?

Answer 37

structural carb; found in insect skeletons

Question 38

what are lipids?

Answer 38

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

Question 39

what are fats constructed of?

Answer 39

1 glycerol & 3 fatty acids

Question 40

what are saturated fats?

Answer 40

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

Question 41

what are unsaturated fats?

Answer 41

less hydrogen, one carbon-carbon bond, liquid oils at room temp; cis double bond causes molecules to bend in curved shape; plant & fish fats

Question 42

what is hydrogenation?

Answer 42

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

Question 43

what is LDL

Answer 43

bad cholesterol

Question 44

what is HDL

Answer 44

good cholesterol

Question 45

parts of a phospholipid?

Answer 45

head-> choline, phosphate, and glycol two fatty acid tails

Question 46

what is surrounding charged molecules?

Answer 46

halo of water which makes it hydrophobic

Question 47

types of proteins

Answer 47

-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

Question 48

what are amino acids?

Answer 48

organic molecules with amino acid & carboxyl groups

Question 49

what are R groups?

Answer 49

functional group of each amino acid; hydrophobic R groups-> carbon & hydrogen; hydrophilic R groups-> electric charged and polar

Question 50

how is a protein?

Answer 50

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

Question 51

what is sickle cell disease?

Answer 51

mutation of Heme subunit