4) Biological Membranes

Question 1

Biological membranes

Answer 1

Complex structures consisting of many molecules

Specialised function

Question 2

Basic functions of bio membranes

Answer 2

Barrier function
Physically separates cell from environment
Divides cell into many smaller compartments with diverse functions

Metabolic
Ensures high speed and efficiency due to large total area

Question 3

Asymmetrical bio membranes

Answer 3

Definition the surface has different compositions, structure and functions

Each membrane has 2 surfaces inner and outer

Question 4

Types of bio membranes

Answer 4

Natural
Artificial
Modified
Intact has original structure and function

Question 5

Factors affecting biomembranes

Answer 5

Charge to charge
Charge to dipole
Dipole to dipole
Induced dipole

Charge induced dipole
Dipole induced dipole

Question 6

Hydrophobic interactions

Hydrophilic

Answer 6

When hydrophobic molecules are placed into water it takes up space between water molecules restricting ability to form hydrogen bonds

Form h bonds easily with water this creates attractive force

Question 7

Lipids

Answer 7

Phospholipids
Steroids

Hydrophilic head and hydrophobic tail that is a fatty acid tail

DRAWING

Question 8

Proteins

Answer 8

Drivers function

Molecular mass from 10000 to 1000000 daltons

Question 9

Water

Answer 9

Free mobile phase exchangeable with water inside and outside of cell

Capture is when the mobile lander is surrounded by lipids which is exchanged with water inside or outside of the cell

Bonded is when immobile water molecules surround polar parts of lipids

Question 10

Model of hotter and Grendel

Answer 10

Membranes are made from a lipid bilayer

drawing

Lipids extracted from membranes form a monomolecular layer of twice the area of original membrane

Question 11

Model of Davson and danielli

Answer 11

Double lipid layer is coated on both sides by globular proteins

DRAWING

Bilayer is Punctured with pores lined by proteins

Question 12

Model of zahler

Answer 12

Proteins are floating on the surface of the lipid bolster snd partially submerged in it

Question 13

Fluid mosaic model part 1

Lipid

Answer 13

The lipid builds a double layer with its hydrophobic fatty acid tail and hydrophilic heads

At physiological temp the lipids are in mesomorphous state
That is ordered and has structure

Cholesterol molecules insert between the hydrophobic tails

Question 14

Proteins and carbohydrates

Answer 14

Peripheral
Proteins are placed on the surface of the lipid bilateral and are partially submerged in the bilayer

Intergral
Span the entire bilayer

Carbohydrates
Attach to proteins and lipids on the extracellular surface

Question 15

Asymmetrical properties

Answer 15

External leaflet of the bilayer is more dense

Contains more phospholipids and cholesterol

Fatty acid chains are more saturated

Question 16

Membrane variability and dynamics

Answer 16

Continuous replaced of the molecules with new ones

Half life
Proteins have 2 -140 hours
Lipids have 14-80 hours

Question 17

Artificial membranes

Composition, shape and structure

Answer 17

Composition
Lipids only
Lipids and proteins

Shape
Flat membranes
Spherical membranes

Structure
Monomolecular layer
Bilayer
Multilayer

Question 18

Flat monolayer

Answer 18

Formed by water and air boundary by single layer of lipids

Used to investigate:
Changes of the state of lipids at different temperature
Area occupied by single lipid molecule in different states

Question 19

Flat bilayer

Answer 19

Both surfaces of the membrane are in contact with water

Used to study:
Electrical resistance of membranes
Generation of surface electric charge on membranes

Question 20

Spherical

Answer 20

Water dispersion of lipids

Micells
Monolayer spherical membranes

Liposomes
Spherical membranes consisting of one or more lipid bilayer

Question 21

Applications of lysosomes

Answer 21

Investigation of the structure of lipid bilayers

Investigating the permeability of membranes to various substances

Deliver of drugs into cells