Bio 105 Chapter Five

Front 1

What two characteristics do all cells have in common?

Back 1

All cells have plasma membrane which controls the passage of water/gas/molecules in and out. All cells have hereditary info that they pass on to daughter cells.

Front 2

Describe some characteristics of prokaryotes

Back 2

"before nucleus"
archaea and bacteria
high level of diversity confined to a cell

Front 3

Describe some characteristics of eukaryotes

Back 3

"true nucleus"
plants/animals/fungi/protitsts etc

Front 4

What is the outer living limit of a cell? What is its function?

Back 4

The outer living limit of a cell is the plasma membrane. The plasma membrane holds the components of a cell together and serva as a barrier or "gate keeper" for things that move in and out of the cell

Front 5

Why are the phospholipid heads of the plasma membrane always pointed towards the cytosol and the extracellular fluid, whereas the tails are always oriented towards the middle of the membrane?

Back 5

the phospholipid heads are always pointed towards the outer limits becaues the phospholipid heads are hydrophilic and polar (like water).
The 2 fatty acid chains only point inwards becaues they are hydrophobic/nonpolar (not like water)

Front 6

What are the 4 main components of the plasma membrane?

Back 6

phospholipid bilayer, cholesterol, proteins, glycoalyx

Front 7

Describe the phospholipid bilayer

Back 7

it gives membrane fluid nature and lets hydrophobic molecules pass through

Front 8

Describe cholesterol of the plasma membrane

Back 8

"patching" material--keeps small molecules from passing through the membrane
keeps optimal fluidity

Front 9

Describe the proteins of the plasma membrane

Back 9

2 kinds- integral and peripheral. integral-bound to the hydrophobic interior, peripheral-on surface of membrane and usually attached to integral proteins.
support structures, signaling antennas, identification markers, cellular passageways

Front 10

Describe the glycoalyx of the plasma membrane

Back 10

simple carbohydrate chains. formal layer on outside of membrane that attach to lipids and proteins.
they are protein binding sites that assist in cellular lubrication/adhesion molecules

Front 11

what is the fluid mosaic model and why is it important to biological organisms?

Back 11

the fluid mosaic model is a conceptualization of the plasma membrane as a fluid, phospholipid bilayer that has within it a mosaic of stationary and mobile proteins.

Front 12

Define diffusion

Back 12

movement of molecules from high concentration to low
ex: dye in water

Front 13

Define osmosis

Back 13

movement of water across the semi-perm membrane from low solute concentration to high solute concentration

Front 14

Define semi-permeable membrane

Back 14

some particles can pass through, others cannot. can control the extent to which certain substances pass through

Front 15

What can and cant pass through the semi-permeable membrane?

Back 15

CAN: nonpolars (ex: lipids), small polars (CO2, H20).
CANNOT: ions/charged molecules (ex: salts dissolved into H20), large polars (glucose), macromolecules

Front 16

Define hypotonic

Back 16

lower concentration of solutes than the cytoplasm of a cell
water flows into cell, causing swelling and expansion of a cell
in extreme conditions, membrane cant stand osmotic pressure of water inside and explodes

Front 17

Define isotonic

Back 17

equal solute concentration in and out of cell
water flows equally in and out
cell size stays the same

Front 18

Define hypertonic

Back 18

a cell environment that has a higher concentration of solutes than in cytoplasm
water will flow out of cell
if enough water is removed in this way, cytoplasm can become so concentrated that the cell can have difficulty functioning

Front 19

how do plant cells prevent cell explosion in hypotonic environments?

Back 19

the cell wall

Front 20

define simple diffusion

Back 20

a form of passive transport. particles simply pass through the membrane

Front 21

define facilitated diffusion

Back 21

transmembrane (integral) proteins form a channel through the cell membrane. channel can be opened or closed and doesnt require energy (ATP)

Front 22

what kind of particles can pass through with simple diffusion?

Back 22

limited to low molecular weight and uncharged molecules. gasses and small organic chemicals can pass through the mem with only simple diffusion.
O2, CO2, alcohol, anesthetics, pesticides, h2o

Front 23

what kind of particles can pass through with facilitated diffusion?

Back 23

glucose, ions, h2o

Front 24

define active transport

Back 24

transmembrane proteins form channel through membrane but require energy.

Front 25

which form of transport moves particles from more to less concentration?

Back 25

facilitated/simple diffusion

Front 26

which form of transport moves from less to more concentration?

Back 26

active transport

Front 27

define exocytosis

Back 27

move out of cell thru transport vesicle which moves in and out of the plasma membrane

Front 28

what are the two parts of endocytosis

Back 28

pinocytosis and phagocytosis

Front 29

define pinocytosis

Back 29

receptors on cell membrane grab molecules and make transport vesicles through invagination

Front 30

define phagocytosis

Back 30

no receptor needed--bacterium or food particles