lecture 2

Question 1

what are the properties of living things?

Answer 1

1. complicated + highly organised
2. structure serves a purpose
3. transforms energy to drive reactions
4. self replication

Question 2

what is the organisational level of biochemicals

Answer 2

1. inorganic precursor (CO2, H2O)
2. metabolites (pyruvate)
3. building blocks (amino acids)
4. macromolecules (proteins, lipids)
5. supramolecular (ribosomes)
6. organelles (nucleus, mitochondria)
7. cell

Question 3

types of bonds
** refer to the image from lectures to identify bonds in image

Answer 3

strong (covalent) vs weak (van der waals, hydrogen- strongest, ionic interactions, hydrophobic interactions)

Question 4

describe hydrophobic interactions

Answer 4

tendency of non-polar molecules, fold up into a ball in water because has hydrophobic parts

Question 5

function of weak bonds

Answer 5

1. maintain biological structure
2. determine biomolecular interactions
3. movement
4. mediate biomolecular recognition

Question 6

define biomolecular recognition

Answer 6

due to weak chemical forces
is the environmental limits in which biological systems can function in

Question 7

bacterial vs animal vs plant cells

Answer 7

bacterial- has flagella (no nuclear membrane)
bacterial + animal- no plastids (give plants colour)
animal- membrane bound organelles
animal + plant- has nuclear membrane
plant- has chloroplast
plant + bacterial- has cell wall

Question 8

membrane functions + how much % of genes encoded in it

Answer 8

1. boundary
2. exclude toxins + ions
3. transport
4. interaction with other cells
5. surface for biological reactions to occur

30%

Question 9

structure of membrane

Answer 9

5nm thick lipid bilayer
contains lipids- provide structure, 500-1000 different types, are amphipathic- has both hydrophobic + hydrophilic parts
also contains proteins- functionary, 3 different types- integral, peripheral and lipid anchored

Question 10

describe micelles

Answer 10

lipids
detergents + soap form micelles- self limiting structures, ball with tails facing inside

Question 11

describe movement of lipids/proteins in mosaic model

Answer 11

lateral, rotationally, flipflop- rare

Question 12

describe membrane phase transitions

Answer 12

depends on transition temp., which is determined by lipid composition of membrane
below transition temp. = tightly packed, gel
above transition temp. = mobile + flexible, liquid crystals

Question 13

4 classes of lipids

Answer 13

1. glycerophospholipids
2. spingolipids
3. cholesterol
4. glycolipids

Question 14

describe glycerophospholipids

Answer 14

• essential
  -3 major types found in mammals
  - phosphatidylethanolamine
  - phosphatidylserine
  - phosphatidylcholine

Question 15

describe sphingolipids

Answer 15

• important for muscle + nerve membranes
  -invovled in cell signalling + signal transduction
  -if join a fatty acid to it with a amide bond- makes a ceramide
  -but most common form is sphingomyelin

Question 16

describe cholesterol

Answer 16

-vital
-maintains cell structure + fluidity
-at high temp. = low fluidity
-at low temp. = high fluidity

Question 17

describe glycolipids

Answer 17

are basically glycerophospholipids, but with carbohydrates attached

Question 18

define lipid rafts

Answer 18

• localised raised regions of sphingolipids + cholesterol
  -insoluble in non-ionic detergents
  -invovled in cell signalling + signal transduction
  -contains 2x amount of cholesterol + 30% of sphingolipids in rest of membrane