lecture 5-6

Question 1

Extracellular matrix

Answer 1

1. collagen fibers: very elastic and very strong, create tendons, bone with calcium

The extracellular matrix (ECM) is secreted by cells and surrounds them in tissues. It has long been understood to be the structural support for cells since its characteristics set the characteristics of the tissue (i.e. bone compared to cartilage compared to brain)1.

function:

The extracellular matrix helps cells to bind together and regulates a number of cellular functions, such as adhesion, migration, proliferation, and differentiation. It is formed by macromolecules, locally secreted by resident cells.

Question 2

Phospholipid bilayer

Answer 2

1. Inner and outer layer are independent of each other
2. Temperature influences phospholipid bilayer (semi-permeable)
3. You can regulate amount of rna induced for phospholipid bilayer
4. Phospholipids are synthesized regularly, by switching phospholipids and replacing they become more saturated
5. Protieins maintaian position in bilayer via polar and non polar elements

Question 3

Plasma Membrane

• Selectively permeable
• Allows for uptake of key nutrients and elimination of waste products
• Maintains protected environment for cellular processes
• Development of internal membranes = increase in complexity

Answer 3

Plasma Membrane

• Selectively permeable
• Allows for uptake of key nutrients and elimination of waste products
• Maintains protected environment for cellular processes
• Development of internal membranes = increase in complexity

Question 4

Membrane Consists of Proteins in a fluid of lipid molecules

describe bilayer and membrane fluid mosaic model

Answer 4

Fluid mosaic model
- Bilayer is not solid, fluid, consistency of olive oil
- Bilayer: lipid molecules existing in a double layer less than 10 nm thick
- Lipid molecules of bilayer vibrate, flex back and forth
- Rarely lipid molecule switch layers
- Exchanges between layers occurs millions of times per second = synthesis
o Lipid molecules and membrane dynamic

Question 5

• Membrane function = critically maintaining membrane in fluid state

Answer 5

• Membrane function = critically maintaining membrane in fluid state

Question 6

• Mosaic aspect = most membranes contain an assortment of types of proteins
  o Includes proteins in transport, electron transport etc.
  o Larger than lipid molecules, proteins move slower in fluid environment of membrane, small umber of membrane proteins anchor cytoskeleton filaments to membrane and do not move
  o Glycolipids and glycoproteins = carbohydrate groups linked with proteins

Answer 6

• Mosaic aspect = most membranes contain an assortment of types of proteins
  o Includes proteins in transport, electron transport etc.
  o Larger than lipid molecules, proteins move slower in fluid environment of membrane, small umber of membrane proteins anchor cytoskeleton filaments to membrane and do not move
  o Glycolipids and glycoproteins = carbohydrate groups linked with proteins

Question 7

• Relative proportions of lipid and protein in membrane vary depending on membrane
• Plasma membrane = equal amount of protein to lipid

Answer 7

• Relative proportions of lipid and protein in membrane vary depending on membrane
• Plasma membrane = equal amount of protein to lipid

Question 8

• Myelin
  o Sublayer functioning to insulate nerve fibers as cell membranes are composed of mostly lipids (maintaining equilibrium)

Answer 8

• Myelin
  o Sublayer functioning to insulate nerve fibers as cell membranes are composed of mostly lipids (maintaining equilibrium)

Question 9

• ## Proteins and other components forming half of bilayer are different from those forming other half

Answer 9

• ## Proteins and other components forming half of bilayer are different from those forming other half

Question 10

-
- Membrane asymmetry, reflects differences diff. in functions performed on either side of membrane
o Glycolipids + carbs attached to proteins on external side of plasma membrane
o Cytoskeleton binds to proteins on internal side

Answer 10

• Membrane asymmetry, reflects differences diff. in functions performed on either side of membrane
  o Glycolipids + carbs attached to proteins on external side of plasma membrane
  o Cytoskeleton binds to proteins on internal side

Question 11

• Hormones and growth binds to receptor proteins found in only externals surface of plasma membrane

Answer 11

• Hormones and growth binds to receptor proteins found in only externals surface of plasma membrane

Question 12

• Membrane asymmetry:

o Two sides are distincltly different (vary in shape, size, and numbers)

Answer 12

• Membrane asymmetry:

o Two sides are distincltly different (vary in shape, size, and numbers)

Question 13

Lipid Fabric of Membrane

• Lipid moelcuels make up underlying fabric of all biological membranes
• Collectlively lipid referes to divers group of water insoluble molecules includes fats phospholipids (dominant lipids oin membrane) and steroids
• Many organisms can self regulate membranes = not too rigid or over fluid

Answer 13

Lipid Fabric of Membrane

• Lipid moelcuels make up underlying fabric of all biological membranes
• Collectlively lipid referes to divers group of water insoluble molecules includes fats phospholipids (dominant lipids oin membrane) and steroids
• Many organisms can self regulate membranes = not too rigid or over fluid

Question 14

• Phospholipid molecule consisting of head group attached to two chains of C and H = fatty acid
• Head group = glycerol linked to alcohol or amino acids via phosphate group
• Property critical to structure and function = amphipathic (both water loving and water hating)
  o Hydrophobic head and hydrophilic tails
  o Polar molecules = hydrophilic and non plar = hydrophobic

Answer 14

• Phospholipid molecule consisting of head group attached to two chains of C and H = fatty acid
• Head group = glycerol linked to alcohol or amino acids via phosphate group
• Property critical to structure and function = amphipathic (both water loving and water hating)
  o Hydrophobic head and hydrophilic tails
  o Polar molecules = hydrophilic and non plar = hydrophobic

Question 15

• Phospholipids range in degree of unsaturation of fatty acids
  o Straight fatty acid chain = fully saturated, carbons bound to max # atoms
  o Kinked fatty acid chain = Carbon double bond = unsaturated
  o When added to water phoispholipids self assemble 3 types
   Micelle
   Lyposome
   Phos. Bilayer
  o Depends mostly on phos. Concentration

Answer 15

• Phospholipids range in degree of unsaturation of fatty acids
  o Straight fatty acid chain = fully saturated, carbons bound to max # atoms
  o Kinked fatty acid chain = Carbon double bond = unsaturated
  o When added to water phoispholipids self assemble 3 types
   Micelle
   Lyposome
   Phos. Bilayer
  o Depends mostly on phos. Concentration

Question 16

o Phos. Spontaneously form in these aqueous environ. Bc of hydrophobic effect
 HE: tendency of polar molecule to exclude hydrophobic molecules like fatty acids = aggregation of lipid molecules in structures where fatty acid tails interact with each other
 Polar head groups associate with water
 These arrangements favoured= lowest energy state more likely to occur over any other arrangement

Answer 16

o Phos. Spontaneously form in these aqueous environ. Bc of hydrophobic effect
 HE: tendency of polar molecule to exclude hydrophobic molecules like fatty acids = aggregation of lipid molecules in structures where fatty acid tails interact with each other
 Polar head groups associate with water
 These arrangements favoured= lowest energy state more likely to occur over any other arrangement

Question 17

Fatty acid composition and temp vs membrane fluidity
- Fluidity of lipid bilayer influenced by:
o Type of fatty acids
o Temp.

Answer 17

Fatty acid composition and temp vs membrane fluidity
- Fluidity of lipid bilayer influenced by:
o Type of fatty acids
o Temp.

Question 18

• Saturated fatty acids = linear allow for compact

- Unsaturated fatty acids = kinks less room for compact

Answer 18

• Saturated fatty acids = linear allow for compact

- Unsaturated fatty acids = kinks less room for compact

Question 19

• Temp. affects membrane fluidity
  o Lower temp = lower molecule movement, phospholipid forms semi solid, decrease membrane permeability, inhibit protein complexes within bilayer, proteins cannot change shape due to rigidity
  o Higher temp = increased molecule movement too fluid resulting in loss of integrity, membrane is leaky, ion concentration permeability increases lead to cell death
  o Membrane systems equilibrium = mixed of saturated and unsaturated

Answer 19

• Temp. affects membrane fluidity
  o Lower temp = lower molecule movement, phospholipid forms semi solid, decrease membrane permeability, inhibit protein complexes within bilayer, proteins cannot change shape due to rigidity
  o Higher temp = increased molecule movement too fluid resulting in loss of integrity, membrane is leaky, ion concentration permeability increases lead to cell death
  o Membrane systems equilibrium = mixed of saturated and unsaturated

Question 20

c organism can adjust fatty acid composition
- Optimal state of fluidity
o Organism self regulate via unsat. and sat. fatty acid concentration regulation proportion

Answer 20

hh

Question 21

• All fatty acids are initially synthesized as fully sat. molecules w out double C bonds
  o Desaturases, acts on saturated fatty acids by catalyzing and introducing double C

Answer 21

hh

Question 22

• Sterols:
  o Influences membrane fluidity
  o Cholesterol, found in membrane of animals but not plants or prokaryotes
  o Act as membrane buffers at high temp they restrain movement, low temp. sterols disrupt fatty acids from associating by occupying space

Answer 22

• Sterols:
  o Influences membrane fluidity
  o Cholesterol, found in membrane of animals but not plants or prokaryotes
  o Act as membrane buffers at high temp they restrain movement, low temp. sterols disrupt fatty acids from associating by occupying space

Question 23

Membrane proteins – a and b + Key functions
- Proteins associated with membrane determine function
- 4 major functional categories:
 2 major types of proteins

Answer 23

Membrane proteins – a and b + Key functions
- Proteins associated with membrane determine function
- 4 major functional categories:
 2 major types of proteins

Question 24

o Integral: proteins embedded in phospholipid bilayer = transmembrane proteins bc they interact with both sides of membrane
 Transport proteins = provides channel providing movement of specific molecule membrane proteins = changes shape to shuttle specific molecule from one side of membrane to another (channel protein)
 Enzymatic activity
 Signal transduction= membranes contain receptor proteins binding to specific chemicals like hormones, trigger changes on inner surface of membrane
 Attachment and recognition proteins = proteins exposed to inner and outer parts of membrane are attachment point for range of cytoskeleton elements
• Integral membrane proteins interact with membrane hydrophobic core
• Transmembrane proteins have 2 domains
o Domain interacting with lipid bilayer consists of non-polar amino acids
 Creates channels “tampons” aka alpha helix (secondary structure)
o Domain exposed of either side of membrane composed of polar amino acids

Answer 24

o Integral: proteins embedded in phospholipid bilayer = transmembrane proteins bc they interact with both sides of membrane
 Transport proteins = provides channel providing movement of specific molecule membrane proteins = changes shape to shuttle specific molecule from one side of membrane to another (channel protein)
 Enzymatic activity
 Signal transduction= membranes contain receptor proteins binding to specific chemicals like hormones, trigger changes on inner surface of membrane
 Attachment and recognition proteins = proteins exposed to inner and outer parts of membrane are attachment point for range of cytoskeleton elements
• Integral membrane proteins interact with membrane hydrophobic core
• Transmembrane proteins have 2 domains
o Domain interacting with lipid bilayer consists of non-polar amino acids
 Creates channels “tampons” aka alpha helix (secondary structure)
o Domain exposed of either side of membrane composed of polar amino acids

Question 25

• Peripheral: interact with hydrophilic surface
  o Positioned on surface of membrane do not interact hydrophobic core
  o Found on cytoplasmic side of membrane and form part of cytoskeleton
  o Mad of of mixture of polar and non-polar amino acids

Answer 25

• Peripheral: interact with hydrophilic surface
  o Positioned on surface of membrane do not interact hydrophobic core
  o Found on cytoplasmic side of membrane and form part of cytoskeleton
  o Mad of of mixture of polar and non-polar amino acids

Question 26

• Hydrophobic nature of membrane = restrictions

- O2 and CO2 necessary and diffuse quickly= good due to their vital role

Answer 26

• Hydrophobic nature of membrane = restrictions

- O2 and CO2 necessary and diffuse quickly= good due to their vital role

Question 27

• Passive transport:
  o Movement of molecules across membrane without expending chemical energy
  o Molecules move by diffusion
  o Primary mechanism of solute movement
  o Driving force of diffusion = entropy
  o Rate of passive transport depends on concentration gradient
  o Equilibrium = maximum entropy= no net concentration
  o 2 types:
   Simple diffusion
  • Movement of molecules directly across a membrane without involvement of a transporter
  • Rate of simple diffusion depends on molecular size lipid solubility
  • Easily cross membrane: uncharged ions, small molecules, o2 c2 etc.
   Facilitated diffusion
  • Depends on membrane proteins
  • Follows concentration gradients
  • Is specific for certain substances
  • Becomes saturated at high concentrations of transported substance
  • Movement of molecules across membrane with aid of transporter
  • Amino acids, sugars ions and other polar and charged molecules need assistance
  • 2 groups of transport proteins carry out facilitated diffusion (form hydrophilic pathways in membrane)
  o Channel proteins
  o Carrier proteins
  • Aquaporins:
  o Water-specific transport proteins for diffusion of water
  o Narrow channel
  • Gated channel:
  o Transporters can switch between open, closed, intermediate
  o Can be opened or closed based in changes of voltage across membrane or via binding signal molecules
  • Carrier proteins:
  o Each c protein binds a single specific solute and transports it across lipid bilayer (uniport transport)
  o During transport, protein undergoes changes (main difference between carrier and channel)

Answer 27

• Passive transport:
  o Movement of molecules across membrane without expending chemical energy
  o Molecules move by diffusion
  o Primary mechanism of solute movement
  o Driving force of diffusion = entropy
  o Rate of passive transport depends on concentration gradient
  o Equilibrium = maximum entropy= no net concentration
  o 2 types:
   Simple diffusion
  • Movement of molecules directly across a membrane without involvement of a transporter
  • Rate of simple diffusion depends on molecular size lipid solubility
  • Easily cross membrane: uncharged ions, small molecules, o2 c2 etc.
   Facilitated diffusion
  • Depends on membrane proteins
  • Follows concentration gradients
  • Is specific for certain substances
  • Becomes saturated at high concentrations of transported substance
  • Movement of molecules across membrane with aid of transporter
  • Amino acids, sugars ions and other polar and charged molecules need assistance
  • 2 groups of transport proteins carry out facilitated diffusion (form hydrophilic pathways in membrane)
  o Channel proteins
  o Carrier proteins
  • Aquaporins:
  o Water-specific transport proteins for diffusion of water
  o Narrow channel
  • Gated channel:
  o Transporters can switch between open, closed, intermediate
  o Can be opened or closed based in changes of voltage across membrane or via binding signal molecules
  • Carrier proteins:
  o Each c protein binds a single specific solute and transports it across lipid bilayer (uniport transport)
  o During transport, protein undergoes changes (main difference between carrier and channel)

Question 28

o Osmosis: Diffusion of water molecules
 Across a selectively permeable membrane
 From a solution of lower solute concentration to a solution of higher solute concentration
 Selectively permeable membrane must allow water molecules to pass but not solute molecules
 Osmosis can occur in bilayer or from aquaporins
• Hypotonic:
o Higher solute concentration inside of cell than outside
o Water enters via osmosis, cell swells
o Turgor pressure in plant cells due to pressure against cell wall
• Hypertonic:
o Higher solute concentration outside of cell than inside
o Water diffuses out of cell
o Animal and plant cells shrink
• Isotonic:
o Concentration of water inside and outside of cell is equal
o Energy cost: pumping ions form one side to another

Answer 28

o Osmosis: Diffusion of water molecules
 Across a selectively permeable membrane
 From a solution of lower solute concentration to a solution of higher solute concentration
 Selectively permeable membrane must allow water molecules to pass but not solute molecules
 Osmosis can occur in bilayer or from aquaporins
• Hypotonic:
o Higher solute concentration inside of cell than outside
o Water enters via osmosis, cell swells
o Turgor pressure in plant cells due to pressure against cell wall
• Hypertonic:
o Higher solute concentration outside of cell than inside
o Water diffuses out of cell
o Animal and plant cells shrink
• Isotonic:
o Concentration of water inside and outside of cell is equal
o Energy cost: pumping ions form one side to another

Question 29

• Active transport requires energy
  o Form ATP
  o 3 main functions of active transport in cell”
   Uptake of essential nutrients from fluid surrounding cells, even when their concentrations are lower than in cells
   Removal of secretory waste materials from cells or organelles even when concentration of those materials is higher outside the cells or organelles
   Maintenance of essentially constant intracellular concentrations of H+ etc.
  • Charged ions contributes to voltage = creates potential difference aka membrane potential
  o Primary Active Transport:
   The same protein that transports the molecules hydrolyzes ATP to power transport
   Moves positively charged ions across membranes
   H+ pumps (proton pumps)
   Ca2+ pump
   Na+ /K+ pump
  o Secondary Active transport:
   Transport directly driven by ATP
   Transport proteins do not break down ATP
   Instead use a favourable concentration gradient of ions as their energy source
  • Symport
  o Cotransported solute moves through membrane channel in same direction as driving ion
  • Antiport
  o Driving ion moves through membrane channel in one direction, providing energy for active transport of another molecule in opposite direction

Answer 29

• Active transport requires energy
  o Form ATP
  o 3 main functions of active transport in cell”
   Uptake of essential nutrients from fluid surrounding cells, even when their concentrations are lower than in cells
   Removal of secretory waste materials from cells or organelles even when concentration of those materials is higher outside the cells or organelles
   Maintenance of essentially constant intracellular concentrations of H+ etc.
  • Charged ions contributes to voltage = creates potential difference aka membrane potential
  o Primary Active Transport:
   The same protein that transports the molecules hydrolyzes ATP to power transport
   Moves positively charged ions across membranes
   H+ pumps (proton pumps)
   Ca2+ pump
   Na+ /K+ pump
  o Secondary Active transport:
   Transport directly driven by ATP
   Transport proteins do not break down ATP
   Instead use a favourable concentration gradient of ions as their energy source
  • Symport
  o Cotransported solute moves through membrane channel in same direction as driving ion
  • Antiport
  o Driving ion moves through membrane channel in one direction, providing energy for active transport of another molecule in opposite direction

Question 30

4. 6 Exocytosis and endocytosis
   - Eukaryotic cells import larger molecules via endo and exocytosis
   - Both processes require ATP

Answer 30

4. 6 Exocytosis and endocytosis
   - Eukaryotic cells import larger molecules via endo and exocytosis
   - Both processes require ATP

Question 31

Exocytosis:
- Releases molecules to the outside via secretory vesicles
o Secretory vesicles move through cytoplasm and contact plasma membrane + release contents to cell exterior
 Animal: cells secrete glandular and peptide hormones
 Plants: secrete carbohydrates to build strong cell wall

Answer 31

Exocytosis:
- Releases molecules to the outside via secretory vesicles
o Secretory vesicles move through cytoplasm and contact plasma membrane + release contents to cell exterior
 Animal: cells secrete glandular and peptide hormones
 Plants: secrete carbohydrates to build strong cell wall

Question 32

Endocytosis:
- Brings materials into cells via endocytic vesicle
- Two phases:
o Bulk phase endocytosis:
 extracellular water is taken in among any molecules happening to be in solution with the water (0 binding of surface receptors)
o Receptor-mediated endocytosis:
 molecules taken in are bound to outer cell surface via receptor proteins (integral proteins of plasma membrane), bind certain molecules, create coated pit (formed form network proteins called clathrin – reinforce cytoplasmic side)
 pit pinches free form plasma membrane – forms endocytic vesicle and loses clathrin coat and fuses with lysosome
 enzymes in lysosome digests contents of vesicle, breaks down molecules into small bits
 Small molecules enter vesicle membrane via transport proteins
 Phagocytosis : form of endocytosis
Two processes cycle membrane segments between internal cytoplasm and cell surface = maintains surface area of plasma membrane @ controlled levels

Answer 32

Endocytosis:
- Brings materials into cells via endocytic vesicle
- Two phases:
o Bulk phase endocytosis:
 extracellular water is taken in among any molecules happening to be in solution with the water (0 binding of surface receptors)
o Receptor-mediated endocytosis:
 molecules taken in are bound to outer cell surface via receptor proteins (integral proteins of plasma membrane), bind certain molecules, create coated pit (formed form network proteins called clathrin – reinforce cytoplasmic side)
 pit pinches free form plasma membrane – forms endocytic vesicle and loses clathrin coat and fuses with lysosome
 enzymes in lysosome digests contents of vesicle, breaks down molecules into small bits
 Small molecules enter vesicle membrane via transport proteins
 Phagocytosis : form of endocytosis
Two processes cycle membrane segments between internal cytoplasm and cell surface = maintains surface area of plasma membrane @ controlled levels

Question 33

Pathways:

1. Reception:
   a. Binding of signal molecule with specific receptor on target cells
   b. Most receptors found on plasma membrane, can also be found on internal membranes (ER)
   c. Other receptors: soluble proteins found in cytoplasm

Answer 33

Pathways:

1. Reception:
   a. Binding of signal molecule with specific receptor on target cells
   b. Most receptors found on plasma membrane, can also be found on internal membranes (ER)
   c. Other receptors: soluble proteins found in cytoplasm

Question 34

2. Transduction:
   a. Process where signal reception triggers changes within cell to cause cellular response
   b. Cascade of reactions including several diff. molecules (signalling cascade)

Answer 34

2. Transduction:
   a. Process where signal reception triggers changes within cell to cause cellular response
   b. Cascade of reactions including several diff. molecules (signalling cascade)

Question 35

3. Response:
   a. Transduction signals causes specific cellular response
   b. Diff. signalling pathways = different downstream responses (eg: activation of specific enzyme causes changes in gene expression)

Answer 35

3. Response:
   a. Transduction signals causes specific cellular response
   b. Diff. signalling pathways = different downstream responses (eg: activation of specific enzyme causes changes in gene expression)

Question 36

Signal reception triggers response pathways in cell (Transduction)
- Binding activates cascade
- Common characteristic of signalling mechanisms: signal is relayed inside cell via protein kinases (enzymes transferring phosphate group from ATP to sites of proteins)
- Protein Kinases: only active when surface receptor binds to a signal molecule
- Protein Kinases acts in chain called phosphorylation cascade
o Last protein in cascade is known as target protein
o This protein is stimulated or inhibited
o Protein phosphatases: remove phosphate groups from target proteins, always active in cells
- Characteristic of signal transduction pathways: amplification:
o Increase in magnitude of each step as transduction pathway proceeds
o Occurs when proteins carrying out pathway are enzymes
o More enzymes-catalyzed steps in reaction = greater amplification = few extracellular signal molecules binding to receptors can proceed full internal response
 

Answer 36

Signal reception triggers response pathways in cell (Transduction)
- Binding activates cascade
- Common characteristic of signalling mechanisms: signal is relayed inside cell via protein kinases (enzymes transferring phosphate group from ATP to sites of proteins)
- Protein Kinases: only active when surface receptor binds to a signal molecule
- Protein Kinases acts in chain called phosphorylation cascade
o Last protein in cascade is known as target protein
o This protein is stimulated or inhibited
o Protein phosphatases: remove phosphate groups from target proteins, always active in cells
- Characteristic of signal transduction pathways: amplification:
o Increase in magnitude of each step as transduction pathway proceeds
o Occurs when proteins carrying out pathway are enzymes
o More enzymes-catalyzed steps in reaction = greater amplification = few extracellular signal molecules binding to receptors can proceed full internal response
 

Question 37

sterols function

Answer 37

used to regulate

Question 38

are alpha helix channels hydrophilic or hydrophobic

are they efficient

Answer 38

hydrophobic

yes

Question 39

advantage of enzymatic proteins embedded side-by-side in plasma membrane?

Answer 39

facilitates several steps in same enzymatic pathways being spatially linked

Question 40

Passive transport is based on diffusion what does that mean for concentration gradients

Answer 40

goes from high to low

Question 41

K+ Voltage Gated Channel

Answer 41

every single ion possesses a voltage gated channel specific for it
important for fast muscle contraction must build up high concentration gradients
very selective

Question 42

carrier proteins

Answer 42

amoutn differes based on different metabolicc rates

Question 43

why would a plant in normal conditions create a greater solute concentrations within plants relative to the extracellular solution

Answer 43

promote water uptake, maintains tension (turgor pressure), increase cellular streaming for structural support

Question 44

difference energy wise between carrier and active transport

Answer 44

carrier = no atp

active needs atp

Question 45

how are H+ pumps, Ca2+, Na and K pump able to create membrane potential

Answer 45

by creating concentration gradients

Question 46

Active transport of ions creates what

Answer 46

voltage

Question 47

What is membrane potential

Answer 47

electricxal potential diffference across plasma membrane

Question 48

The Na+ and K+ pump

Answer 48

creates e;ectrochrmical gradient, stored energy used for other transport mechanisms, uself in many physiological processes

Question 49

Symport

Answer 49

ATP needed, with concentration gradient

Question 50

Antiport

Answer 50

Against concentration gradient

Question 51

is bulk phase selective, are cathrins involved

Answer 51

no, and no

Question 52

clathrins

Answer 52

protein layer, adds extra support to plasma membrane, receives signal for protein receptors and collapses into the cell, initiates collapse and creation of vesicle

Question 53

phagocytosis is a form of

Answer 53

endocytosis

Question 54

Role of membrane in cell singalling

Answer 54

sensing and responding to changes in the environment

Question 55

phosphorylation cascade

Answer 55

domino, cascade effect, protein phosphate remove phosphate group of switch signals, phosphorylation cascades phosphorylate to phosphorylate