Biological molecules

Question 1

are h-bonds strong ?

Answer 1

no

Question 2

liquid water explanation ( h-bonds and b.p?)

Answer 2

molecules h-bond together creating high b.p as h2o bonded together and therefore cant escape as gases easily

Question 3

Ice explanations hydrogen bonds and strenght

Answer 3

less movement as less KE

more h-bonds form less break

Question 4

H-bonds and temp changes

Answer 4

h-bonds in water (liquid) hold H2O molecules= restrict movement. lots of energy needed to increase temp, keeps lakes stable
evaporation of H2O = lots of energy and removes heat

Question 5

which is denser. Ice or H2O

Answer 5

ice i sless dense. allowing it to float on top, ie iinsulating layer on lakes

Question 6

droplet shape of water?

Answer 6

help by h-bonds, giving shape. Cohesion

Question 7

what allows something to be soluble?

Answer 7

balanced bonds, h - bonds

Question 8

water is a large ________________________ in the body

Answer 8

transport median

Question 9

Acid and amine group in amino acid?

Answer 9

amine group = H\ N
H/
acid = c=o
\OH

Question 10

amino acid formula

Answer 10

NH2CHRC=OOH

Diagram

Question 11

Bonding of amino acids

Answer 11

condensation reaction - H2O produced.

OH + H bond = bond between C-N occurs

Question 12

reverse of condensation =

Answer 12

hydrolysis

Question 13

protein primary structure

Answer 13

specific sequence of amino acids

Question 14

secondary structure

Answer 14

refers to coiling and pleating of parts of polypeptide molecule:
either alpha helix or beta pleated sheet
h-bonds hold coil in place theyre weak but there a re lots so = strong!

Question 15

Tertiary structure

Answer 15

overall 3D structure of final protein molecule

Question 16

tertiary deeper

Answer 16

coils/ pleats often with straight runs of amino acids between. many types of bonding/interactions occur;
disulfide bonds
ionic bonds
hydrogen bonds
hydrophobic + hydrophilic interactions.
specific to protein function ie hormone must be specific to fit hormone receptor of a target cell

Question 17

quaternary structure

Answer 17

some proteins made up of more than one polypeptide subunit joined together. eg; haemoglobin + insulin

Question 18

structure of haemoglobin

Answer 18

transport protein
consists of 4 polypeptide subunits ( 2 alpha and 2 beta)
a water soluble globular protein

Question 19

function OF HAEM

Answer 19

carry O2 from the lungs to the tissues
haem group contains Fe2+ ion 
haem group = colour (purple +oxy --> Bright red) 
O2 binds to haem, 4 max 
haem = prosthetic group

Question 20

collagen structure

Answer 20

fibrous structural protein
3 polypeptide chains wound together like a rope
1 chain is coiled and made from 1000 amino acids
hydrogen bonds between chains form (giving strength)
also each collagen molecule foroms covalent bonds (cross links) between other collagen molecules ( resulting in a collagen fibric. many = collagen fibre)

Question 21

function of collagen

Answer 21

provides strength
eg in the walls of arteries
bones formed from collagen
cartilage and connective tissues

Question 22

alpha glucose : ( monosacharides ) 3 things

Answer 22

soluble in H2O
form crystals
are sweet
DIAGRAM (6 one off 5. O at 6 and H above OH for alpha (beta swap))

Question 23

joining monosaccharides + splitting disaccharides

Answer 23

condensation reaction
reverse = hydrolysis ( glysocsidic bonds)
OH + H = H2O

Question 24

2 alpha- glucose bonded form disacharide caleed

Answer 24

maltose

Question 25

starch structure:

Answer 25

mixture of long, straight-chain amylose & branched amylopectin
alpha glucose
energy store- can be broken down into glucose molecules
insoluble

Question 26

cellulose

Answer 26

beta glucose polymer chain
h-bonds between monomers
crosslinked by h-bonds to form microfibrils
h-bond again –> macrofibrils
ebedded with polysaccharide glue of substances called pectins

Question 27

trigylceride molecule =

and how they bond

Answer 27

1 glycerol molecule bonded to 3 fatty acids
condensarion reaction = ester bond
theyre insoluble and hydrophobic

Question 28

phospholipid

Answer 28

glycerol molecule, 2 fatty acid chains and phosphate group
phosphate head = hydrophilic
fatty acid tail hydrophobic

Question 29

whats a triglyceride funstionans solubility

Answer 29

compact negery store. insoluble in water so doesnt affect w.p

Question 30

phospholipid function

Answer 30

forms a molecule which is part hydrophobic and part hydrophilic. idea for membranes

Question 31

cholesterol structure andfunction

Answer 31

4 carbon - based ring structure

fors a small thin molecule that fits into lipid bilayer giving strength and stabilitly

Question 32

food test for reducing sugar;

Answer 32

benedicts test; heat with benedicts solution ( alkaline copper sulfate)
blue –> orange-red ( precipitate)
eat to 80degrees in H2O bath

Question 33

food test for starch

Answer 33

add iodine solution

brown –> blue/black

Question 34

non- reducing sugar food test

Answer 34

benedicts test - doesnt work
boil with HCl, then cool + neutralise with sodium hyrdrogen carbonate solution/ sodium carbonate solution, then repeat beneditcts
blue –> orange/ red

Question 35

protein

Answer 35

add biuret reagent

blue to lilac

Question 36

lipid test

Answer 36

add ethanol to extract (dissolve) lipid and pour alcohol into water ina nother test tube
white emulsion forms near top of water

Question 37

colorimeter

Answer 37

after benedicts test the more light shone through blue liquid the more glucose was present THINK

Question 38

Hydrogen bonding what is it

Answer 38

negative part of a molecule bonds to h+. must aksi have lone pair
eg; H2O