membranes

Question 1

is lipids and water non polar or polar?

Answer 1

lipids are no polar and water is polar

Question 2

what is a micelle?

Answer 2

a spherical arrangement of phospholipids

Question 3

hydrolysis meaning?

Answer 3

breaking something down/ apart using water/ because of the addition of h20

Question 4

what is a condensation reaction?

Answer 4

when a bond is formed that is a condensation reaction. 2 molecules combine to form a large molecule and produce a smaller molecule such as H20 as a byproduct

Question 5

how are phospholipid bilayers formed?

Answer 5

formed when they are placed in an aqueous environment

Question 6

what are transmembrane’s?

Answer 6

transmembrane’s are proteins only within the phospholipid bilayer. they are within which is integral. there are proteins are attached which is peripheral.

they can also be permanent or temporary

gated transmembrane channels allow selected molecules through depending on conditions within the cell which determine whether they open or close.

there transmembrane Chanels allow substances to pass through in both directions. some are active carrier systems which use energy to transport.

Question 7

what are the functions of transmembrane’s (proteins)?

Answer 7

allow for transport of substances that are not able to go (diffuse) through phospholipid bilayer themselves.

ionic, molecular and electron transport

They can be (carrier) which cahnegs shape during facilliated diffusion yet do open and close. or they can be channel which does not change shape during facillitated diffusion. Facillitated iffuiosn is stil passive)

Question 8

what are glycoproteins ?

Answer 8

proteins which have carbohydrate groups attached to them. they allow cells to communicate with one another and are used for immunity.

proteins on the cell surface also act as receptors for incoming messages such as hormones. (proteins used for communication and transport)

Question 9

describe and explain the fluid mosaic model of plasma membrane (cell membrane)?

Answer 9

phospholipid bilayer is not fixed structure/ not rigid/ flexible although the bilayer will always remain arranged in this configuration. Thus membranes can change shape for processes like phagocytosis. It also allows proteins to move latterly within he cell membrane.

fluid - specifically refers to the movement of phospholipids in the plane of the membrane

it is mosaic as it is made up of many macromolecules including glycoproteins, lipoproteins, cholesterol , transmembrane proteins and phospholipids.

mosaic refers to the random arrangement/ association of proteins different shapes and sixes within the membrane/ phospholipid bilayer

Question 10

why is it important for cell membranes to have fluid mosaic model?

Answer 10

carry out function effectively

Question 11

what Can affect fluidity of cell membrane ?

Answer 11

the ratio of saturated and unsaturated fatty acids determins fluidity. cholesterol helps the cell membrane remain correct fluidity. during warmer temperatures it provides structural support to prevent phospholipids from becoming too fluid. cholesterol enhances the permeability bilayer. more cholestrol makes the membrane stabalized and have a higher meltig point.

Question 12

how many fatty acids are there in the fatty acid chain

Answer 12

two fatty acids in fatty acid chain which are hydrophobic

Question 13

describe the structure of the plasma (cell membrane).

Answer 13

The structure of the cell is comprised of a phospholipid bilayer with the phosphate hydrophilic (polar) head pointing outwards and the 2 fatty acid chains
( hydrophobic/ non polar) directing inwards and a glycerol backbone. within the bilayer there are proteins called transmembrane (ionic, molecular, electron transport), these are integral and allow substances which cannot enter/ diffuse through the cell bilayer to enter they are either carrier or channel. In addition to this here are peripheral proteins attached to the outside and slightly within the phospholipid bilayer. plus they have glycoproteins which are proteins with carbohydrate groups they allow for communication between cells. furthermore they contain cholesterol between the fatty acid chains of phospholipid bilayer.

Question 14

what do proteins and transmembrane aid the movement of?

Answer 14

allow the movement/ absorption of large/ charged/ polar molecules. such as water, glucose/ water soluble vitamins.

Question 15

what are the meanings of
Solute
Solvent
Solution
HypErtonic
HypOtonic
Isotonic

Answer 15

solute - substance which is dissolved
solvent - liquid in which the solute is dissolved

solution- solvent with solute dissolved in it

Hypertonic- if the solute concentration is higher in solution than inside cell - in relation to solution

Hypotonic- solute conecntartion is lower outside cell that inside - this in relation to solution

isotonic- concentration of solute inside and outside cell is the same

Question 16

what is osmosis

Answer 16

net movement of water molecules from a solution with a lower concentration of a solute to a higher concentration of a solute through a partially permeable membrane.

Question 17

what is active transport

Answer 17

Active transport is the movement of molecules or ions across a membrane via a carrier protein against their concentration gradient using energy supplied by ATP. Active transport always uses a carrier protein.

Question 18

what are the two main examples of bulk transport and definitions ?

Answer 18

Endocytosis substances into cell.

Exocytosis substances out of cell.

Question 19

what is the purpose of Endo and Exocytosis ?

Answer 19

ions and some molecules are too large to be transported across membrane into cell. eg proteins or bacteria. Instead they are packages in vesicles ( small membrane bound sacks) which fuse together with the membrane

Question 20

is Bulk transport active or passive?

Answer 20

Active and is provided with energy from ATP

Question 21

describe the process of Endocytosis?

Answer 21

Endocytosis transports large molecules or ions into cell by the cell membrane caving inwards to form a cavity around the large molecules or ions (polar| hydrophilic molecules), this is called invagination

Particles are then encircled to form a vesicle which moves into cell.

Question 22

Why can’t Ions go through transmembrane proteins ?

Answer 22

Charged atoms or molecules of any size cannot cross the cell membrane via simple diffusion as the charges are repelled by the hydrophobic tails in the interior of the phospholipid bilayer. there for Betty need to be transported in a vesicle.

Question 23

what is the difference between a micelle and a vesicle

Answer 23

a micelle is a spherical arrangement of phospholipids where as a vesicle is a spherical arrangement of a phospholipid bilayer with ions or molecules inside it.

Question 24

describe the process of Exocytosis?

Answer 24

Exits of proteins, hormones, certain enzymes etc.

At beginning portions found in Golgi apparatus. here portions are modified before secreted .Next vesicle containing containing substance buds of Golgi apparatus towards cell membrane, then fuse with cell membrane and protein is secreted.

Question 25

Does active transport:
require energy?
types of transport?
types of molecule?
importance?

Answer 25

It requires energy

Bulk (vesicular), exocytosis and endocytosis, phagocytosis, pinocytosis.

Ions, glucose, amino acids (any polar molecule)

Allows important polar molecules and ions to enter and exit cell cytoplasm.

Question 26

Does passive transport:
require energy?
Types of transport?
Types of molecule?
Importance?

Answer 26

Does not require energy

Osmosis, facilitated diffusion, simple diffusions.

oxygen, carbon dioxide, gases, water

important roles in homeostasis, movement of substances into and out of the cell, keep conditions within normal ranges inside the cell and the organism as a whole.

Question 27

draw the structure of an amino acid ?

Answer 27

glycine is the simplest amino acid. H side is amino group O side is acid group aka carboxyle group.

Question 28

what is the only thing that varies in an amino acid ?

Answer 28

only the R group on an amino acid varies due to there being 20 different amino acids there are 20 different R groups.

Question 29

what does a condensation and hydrolysis reaction form in terms of amino acids ?

Answer 29

a condensation reaction forms a dipeptide which is 2 amino acids would together and the water has been created as a byproduct ( It has come out of amino acid to form dipeptide )

when water is then added back to the dipeptide which is hydrolysis the dipeptide turns into 2 separate amino acids.

Question 30

what is a dipeptide and a polypeptide?

Answer 30

A dipeptide is 2 amino acids bound together and then water is produce as a byproduct - piptide bond

a polypeptide is multiple amino acids bound togethe - peptide bond

Question 31

what is the formation process of proteins.

Answer 31

amino acids (monomers)- dipeptides -polypeptides - proteins (polymers)

Question 32

draw a condensation reaction and a hydrolysis reaction of an amino acid.

Question 33

what are the structures, properties, functions and examples of Fibrous proteins ?

Answer 33

structure: Remain as long chains, several amino acids cross linked together roe extra strength. Only reach secondary structure. Insoluble ( inward facing hydrophilic R groups)

Function: Not very reactive, useful when support and strength is needed .eg. muscle contraction proteins.

examples: Collagen (3 chains with crosslinks). very strong and rigid. used in connective tissue eg skin, bone, muscle.

Question 34

What are the structure, properties and examples of globular proteins?

Answer 34

structure: Polypeptide chain folded into compact spherical shape

properties: Soluble ( outward facing hydrophilic R groups)
Often used in metabolic reactions, easily denatured, useful when shape is important eg enzymes

example: Haemoglobin; four polypeptide chains bound to the prosthetic group (heam) which binds to oxygen.

Question 35

what are each of the structures of protiens

Answer 35

primary:
peptide bond
is the sequence of amino acids

secondary:
hydrogen bond
between amino + acid groups cause polypeptide to twist into a coil called alpha helix and beta sheets

Tertiary
Disulphide/ ionic/ hydrogen/ hydrophobic types of bond
super coiling across to create 3d shape hydrophilic

Quaternary
covalent bonds
protein is made up of more than one peptide linked together eg haemoglobin and collagen

Question 36

clarification on what can go through transmembrane and what processes

Answer 36

channel and carrie transmembrane allow for facilitated diffusion

channel can only transport small, hydrophobic/ non polar (not charged), or polar but uncharge molecules

only carrier proteins can also for active transport

Question 37

what is an enzyme ?

Answer 37

An enzyme is a biological catalyst, as a result they speed up chemical reactions without being used up themselves. This can occur at a cellular level (e.g respiration or whole organism level eg cells in digestion)

They lower activation energy of a substance thus providing a new reaction pathway

They can also be intracellular (in cell) or extracellular (outside cell)

Question 38

example of an intracellular enzyme

Answer 38

Catalyse which breaks down hydrogen peroxide into water and oxygen

Question 39

what is an example of extracellular enzyme

Answer 39

Amylase which breaks down starch into maltose.

Question 40

what type of proteins are enzymes

Answer 40

globular enzymes and therefore are soluble, they alter the rate of metabolic reactions and are described ad biological catalysts

enzyme inhibitors reduce enzyme activity

Question 41

what is enzyme specificity

Answer 41

specificity is the ability for n enzyme to bins with its complimentary substrate out of many substrates do inhibit unwanted reactions.

specificity is determined by the shape of the active site and the enzyme will bind only yo its complimentary active site

Question 42

what is enzyme substrate complex

Answer 42

enzyme substrate complex is the temporary molecule that forms when the enzyme binds to the substrate

Question 43

what is enzyme product complex ?

Answer 43

is the molecule which is formed when the enzyme if attaches to the almost fully complete product before it is released

Question 44

what do enzymes (catalysts) do t the substrate to catalyse the reaction ?

Answer 44

when only one substrate is being broken down the bonds are strained as they fit into the active site
when 2 substrates are being broken down, substrates are brought into close proximity by active site

Question 45

what are the two enzyme catalyst models

Answer 45

lock and key hypothesis
induced fit model

Question 46

what is induced fit model

Answer 46

some proteins conform to the shape of the substrate ( change shape)

when the substrate combines with the enzyme it induces the enzyme to change shape

active site is then moulded into precise conformation making the chemical environment suitable for the reaction

It then lowers activation energy by stretching bonds and product is released

Question 47

how does ph cause enzyme denaturation

Answer 47

If there Is too many H+ present it is more acidic thus if the the enzyme prefers more oh - ions it will become denatures vice vera