Module 1: Composition & Structure Of Membranes

Question 1

Prokaryotic cell

Answer 1

Bacterial cell
Does not contain true nucleus
10x more of these cells than eukaryotic

Question 2

Microbiome

Answer 2

Pop of microorganisms and microbes

Question 3

Microorganisms

Answer 3

Organism not visible to naked eye, only under microscope

Question 4

Streptococcus salivanus

Answer 4

Normal inhabitants of upper respiratory tract and oral cavity
Contributes to dental plaque

Question 5

Staphylococcus haemolyticus

Answer 5

Resides on skin

Pathogen it gets inside body

Question 6

Bacteriodes Thetaiotaomicron

Answer 6

Prédominant intestinal bacteria

Makes enzymes to breakdown plant material

Question 7

Cell

Answer 7

Membrane bound structure containing:

Nucleic acids, proteins, carbohydrates, phospholipids

Question 8

Membrane

Answer 8

Separate internal enviro from external

Question 9

Phospholipids

Answer 9

Consists of glycerol molecule linked to phosphate and two fatty acids

Question 10

Saturated

Answer 10

Single bonds

Question 11

Unsaturated

Answer 11

Double bonds

Question 12

Lipid micelles

Answer 12

Important for absorption of fat-soluble vitamins and complex lipids

Question 13

Lipid raft

Answer 13

Region of lower fluidity
Holds macromolecules together in membrane
Gather proteins/collection of receptors on cell surface

Question 14

Less fluid membrane with fewer unsaturated fatty acids & more cholesterol…

Answer 14

Lower permeability

Question 15

More fluid membrane with more unsaturated fatty acids and less cholesterol

Answer 15

Higher permeability

Question 16

Sélective permeability

Answer 16

Ability of cell membrane to control traffic of substances into and out of cell and its organelles

Question 17

Fluid mosaic model

Answer 17

Membrane consists of proteins and carbohydrates embedded in fluid phospholipid bilayer

Question 18

Passive/simple diffusion

Answer 18

Movement of small molecules in direction of conc. gradient
High to low conc.
No energy required
-lipid soluble molecules, gases, uncharged polar molecules

Question 19

Passive transport

Answer 19

Movement of small molecules with conc. gradient (high to low) but involves embedded proteins in membrane
Does not require energy
-requires help if transmembrane proteins, Ions, hydrophilic molecules

Question 20

Active transport

Answer 20

Movement of molecules against conc. gradient

Fuelled by energy from hydrolysis of ATP

Question 21

Osmosis

Answer 21

Movement of water across membrane

Less concentrated to more concentrated

Question 22

Aquaporin

Answer 22

Exclusively permeable to water

Channel water across membrane from high to low conc.

Question 23

Isotonic environment

Answer 23

Cell in environment or has extracellular fluid concentration with same osmolarity as it’s interior
No net movement of water, cell retain shape and optimal activities

Question 24

Hypotonic environment

Answer 24

Extracellular fluid has a lower solute concentration than inside cell
Results in excessive movement of water leading to sell swelling or bursting

Question 25

Hypertonic environment

Answer 25

Environment with higher solute concentration on exteriors and interiors of cell Net loss of water – quick membrane shrinking and shrivelling

Question 26

Primary active transport

Answer 26

Transmembrane transport proteins directly affected by energy released from ATP hydrolysis and undergoes change to pump substances across membranes against concentration gradient

Question 27

Secondary active transport

Answer 27

Neighbouring transmembrane proteins takes advantage of electrochemical gradient established in primary active transport pumps to move their own solutes against gradient

Question 28

Sodium— potassium pump

Answer 28

Greater concentration of sodium in extracellular fluid relative to interior of cell Greater concentration of potassium in interior than extracellular environment Ratio: 3 sodium:2 potassium