CELL MEMBRANE

Question 1

what the plasma membrane

Answer 1

Boundary that separates living cells from its surroundings – makes life possible

Question 2

amphipathic meaning

Answer 2

have both hydrophobic and hydrophilic regions

Question 3

whats the fluid mosaic

Answer 3

fluid structure with a mosaic of protein embedded - phospholipids can move within the membrane

Question 4

is the lateral motion in the plasma membrane frequent or non frequent

Answer 4

frequent

Question 5

is the flip flop across in the plasma membrane frequent or non frequent

Answer 5

non frequent

Question 6

cholesterol role with the plasma membrane

Answer 6

temperature buffer
- has strong enough hydrophobic interactions to anchor itself within the fatty acid tails - preventing it from becoming too fluid at high temp
- has strong enough hydrophilic interactions to interact with the polar head groups - preventing it from becoming too rigid at low temps

Question 7

3 Types of protein that make up the mosaic

Answer 7

• integral= inserted into hydrophobic middle
• trans (type of integral protein) = spans the entirety of cell membrane
• peripheral = on surface

Question 8

6 Protein functions

Answer 8

Transport things across cell surface
Enzymatic activity – break down something / build something up
Signal transduction
Cell–cell recognition
Intercellular joining
Attach to surface

Question 9

do charged things pass through membrane

Answer 9

no

Question 10

does O2 + CO2 pass through membrane

Answer 10

yes - will diffuse freely - nonpolar

Question 11

what is Selective permeability

Answer 11

membrane selects what goes through it

Question 12

what are transport proteins

Answer 12

allow polar / hydrophilic things to go across membrane (can have hydrophilic channel) - specific for what they transport e.g aquaporins transport water

Question 13

2 types of transport proteins

Answer 13

Channel
Carrier

Question 14

what is passive transport

Answer 14

no energy
- uses principles of diffusion (tendency of molecules to spread evenly in space – high -> low conc)

Question 15

what is active transport and some examples

Answer 15

uses energy (ATP) – goes against conc gradient
- Ion pump – sodium potassium pump – electrogenic pump
- Co-transport – sucrose cotransporter
- Bulk transport

Question 16

whats osmosis

Answer 16

diffusion of H2O across a semi permeable membrane

Question 17

whats hypertonic solution

Answer 17

more dissolved in solution outside – H2O moves out (cell = shriveled)
- cell = plazmolyzed in plants

Question 18

whats hypotonic solution

Answer 18

not much dissolved in solution outside – H2O moves in (cell = lysed)
- healthy state for plant cell – cell wall stops it bursting (cell = turgid)

Question 19

whats isotonic solution

Answer 19

equal amounts inside and outside of cell - equilibrium
- healthy state for animal cell
- cell = flaccid in plants

Question 20

whats facilitated diffusion

Answer 20

transport proteins speed up the passive movement of molecules across plasma membrane e.g. channel and carrier proteins

Question 21

whats Endocytosis and its 3 types

Answer 21

brings things into cell
- Phagocytosis (cellular eating - solid)
- Pinocytosis (cellular drinking - liquid)
- Receptor-mediated endocytosis

Question 22

whats Exocytosis

Answer 22

takes things out of the cell

Question 23

whats metabolism

Answer 23

totality of an organisms chemical reactions
- Metabolic pathways begin with a specific molecule and ends with a specific product

Question 24

whats a catabolic pathway

Answer 24

breaks down complex molecules to simpler compounds, releases energy

Question 25

whats an anabolic pathway

Answer 25

builds complex molecules, consumes energy

Question 26

whats bioenergetics

Answer 26

study of how organisms manage energy resources

Question 27

whats energy and its 2 types

Answer 27

capacity to cause change
- Kinetic - energy of motion
- Potential – energy of position

Question 28

how does ATP work

Answer 28

ATP adds its phosphate to molecules – makes them higher energy, less stable, greater work capacity

Question 29

whats thermodynamics and its 2 types

Answer 29

study of energy transformation
- Closed systems – everything is over once reached equilibrium
- Open systems – things keep coming into the system (life is open system – energy of sun keeps coming into it)

Question 30

2 laws of thermodynamics

Answer 30

• 1st law = energy of the universe is constant
  energy can be transferred / transformed but not created
• 2nd law = in every energy transfer/transformation, some energy in unusable and lost as heat

Question 31

what is Lost energy called

Answer 31

entropy - disorder

Question 32

Gibbs free (G) energy equation

Answer 32

ΔG = ΔH - TΔS
- ΔG - can do work
- ΔH - total energy
- TΔS - cant do work

Question 33

whats an exergonic reaction

Answer 33

energy released (ΔG < 0)
- spontaneous - reaction NOT driven from input of energy (negative ΔG)
- REACTANTS have greater capacity to do work + are less stable

Question 34

whats an endergonic reaction

Answer 34

energy required (ΔG > 0)
- non-spontaneous - reaction driven from input of energy (positive ΔG - gets given energy)
- PRODUCTS have greater capacity to do work + are less stable

Question 35

what does it mean when something has more free energy

Answer 35

• higher G
• Less stable
• Greater work capacity

Question 36

what does it mean when something has less free energy

Answer 36

• lower G
• More stable
• Less work capacity

Question 37

what’s the activation energy barrier

Answer 37

energy required for reaction to happen – energy speed bump
- all reactions have them – spontaneous + non spontaneous

Question 38

how do enzymes lower AEB

Answer 38

Orientating substates correctly
Straining substrate bonds
Providing a favorable microenvironment
Correctly bonding to subsrtate

Question 39

what 2 factors are enzymes affected by

Answer 39

temp + pH

Question 40

what 2 chemicals can influence enzyme activity

Answer 40

• Co-factors – non-protein enzyme helpers – inorganic metals or small organics
• Co-enzymes – organic factors

Question 41

2 types of Enzyme inhibitors

Answer 41

• competitive inhibitors – bind to active site of enzyme
• Non-competitive inhibitors – bind to a place other than active site – cause confromational change making the active site less efficient (allosterie)

Question 42

what is Allosteric regulation and its 2 types

Answer 42

can inhibit or stimulate enzyme activity – molecule binds to a location and causes a change elsewhere
- Activator - stabilizes the enzyme in active form
- Inhibitor – stabilizes enzyme in its inactive form

Question 43

what’s a Feedback inhibitor

Answer 43

product of a metabolic pathway shuts down the pathway