2.1.2 Biological molecules Flashcards
Cohesion
water molecules stick together e.g transpiration stream or apoplast movement
High Latent heat
large amount of energy required to change liquid to gas
evaporation is a cooling mechanism so sweat cools you down
High specific heat capacity
large amount of energy required to change temperature therefore stable enviroment for aquatic organism so organisms use less energy on temperature control
helps organisms maintain body temp
ice is less dense than water
ice provides habitat for organisms
water beneath is insulated so it doesnt freeze so organisms dont freeze and can still swim
Universal solvent
transport medium
allows chemical reactions to occur quicker
surface tension
habitat for invertebrates
runs of waxy surfaces
water molecules cling tightly at water surface causing it to bead
Roles of Cholesterol
Regulates fluidity of membranes
waterproofing skin
makes bile
Molecules that bind with cholesterol to form LDL’s
lipids
fats
protein
thermoregulation definition
removes heat energy through sweat evaporating
hydrogen bond definition
weak bond formed between slightly electronegative atom and a slightly positive atom in a different molecule
water molecule forms up to 4 H bonds
properties of water
high surface tension
universal solvent
cohesion and adhesion
high heat capacity
change in density
what are carbohydrates made of
carbon
hydrogen
oxygen
Monosaccharides
sweet + soluble
quickly broken down in respiration to release energy
glucose, fructose, galactose
Disaccharides
2 monosaccharides
less sweet
used for short term energy storage
maltose, sucrose, lactose
polysaccharides
long term energy storage
cellulose in plant
starch, glycogen, amylose
why aren’t polysaccharides classed as sugars
very large
insoluble in water
used for energy storage and structural components
amylopectin
branched
1-6 glycosidic bonds
used for energy storage
compact structure
made of alpha glucose
1-4 glycosidic bonds
found in plant
amylose
form long helix
no branches
found in plant
1-4 glycosidic bond
has hydrogen bonds
compact structure
made of alpha glucose
glycogen
most branched
found in animals
very compact
1-4 and 1-6 glycosidic bonds
alpha glucose
what lipids made of
C,H,O
what proteins made of
C,H,O,N,S
what are nucleic acids made of
C,H,O,N,P
difference between alpha glucose and beta glucose
alpha glucose OH is on the bottom beta glucose OH is on the top
Triglyceride structure
1 glycerol and 3 fatty acids tails
glycerol backbone
what’s the difference between triglycerides
can be saturated or unsaturated
can be different lengths
cellulose
beta glucose
straight chain not coiled or branched
make hydrogen bonds with eachother forming microfibrils
make fibres
strong and insoluble
used to make cell walls
phospholipid structure
glycerol backbone
2 fatty acids- one saturated one unsaturated
1 phosphate head
what is the bond between the glycerol and the fatty acid
ester
macromolecules definition
very large molecule
cholesterol
a sterol
positioned between the phospholipid with the hydroxyl groups at the periphery of the membrane
adds stability and regulates fluidity
keeps them fluid at low temp and prevents them becoming too fluid at high temp
examples of cholesterol
making bile
making steroid hormones
vitamin D
what are sterols
steroid alcohols
complex alcohol molecules based on a 4 carbon ring structure with hydroxyl group at one end
hydroxyl group is polar and hydrophilic
rest of it is hydrophobic
phospholipid bilayer formation
hydrophobic tails point towards the centre away from water and hydrophilic heads face the water
roles of lipids
membrane formation and creation of hydrophobic barriers
hormone production
electrical insulation for impulse transmission
waterproofing
buoyancy for aquatic animals
thermal insulation
cushioning to protect vital organs
Test for lipids
emulsion tes
what is a protein
polymer made of amino acids
structure of amino acid
amine group -NH2
R group = variable group
carboxylic acid group
bond formed between 2 amino acids
peptide bond
what connects when 2 amino acids are joined
H on an amine and OH of the carboxylic acid
what reaction is it when 2 amino acids join
condensation reaction
primary structure
order of amino acids and the peptide bonds
secondary structure
local folding of chain
created by hydrogen bonds between carboxylic acids and amines
alpha helix- every 4 amino acids
beta pleated sheets - between adjacent amino acids antiparrallel
tertiary structure
folds to make 3D structure
caused by interactions between R groups
bonds responsible for tertiary structure
hydrogen
hydrophilic
hydrophobic
ionic
disulphide
quaternary structure
protein made of more than 1 chain
any of the tertiary bonds hold them together
conjugated protein
protein with non protein attached - prosthetic group
Globular proteins
compact and spherical shape
functional - they do something
soluble in water due to hydrophilic R groups on the outside
what does the arrangement of amino acids do for a globular protein
makes them have specific shapes to bind to s a specific receptor
eg enzyme active site
how does a spherical shape with hydrophilic groups on the outside effect globular protein
water soluble to transport around the body
eg enzymes transported in bile
how does relatively unstable structures affect globular protein
sensitive to environmental change = useful for maintaining homeostasis
allows antibodies and enzymes to be flexible and bind to many pathogens or substrates
examples of globular proteins
enzyme
insulin
transport protein
use of enzyme as globular protein
specific active site shape
dissolves in saliva
use of insulin as globular protein
chemical messenger in intracellular signalling
soluble
specific shape
use of transport protein as globular protein
haemoglobin transports O2
acts as channel and carrier proteins in the plasma membrane
has iron to bind O2
soluble
Fibrous protein
long straight chain
high tensile strength
insoluble in water
structural - they are something
why being long straight chain good for a fibrous protein
strong for protection
eg skin protects blood vessels
why being insoluble in water good for a fibrous protein
don’t want them to dissolve and disappear
examples of fibrous proteins
collagen
keratin
elastin
collagen
flexible so protects and allows for stretching
eg skin and ligaments
keratin
in hair and nails - protects more vulnerable body parts
hair keeps us warm as long and thin and traps air
elastin
found in skin and blood vessels to stretch and recoil to maintain BP
alveoli stretch and recoil to make sure all air is breathed out
Nitrate
NO3-
nitrogen supply for plants
anion
hydrogen carbonate
HCO3 -
maintain blood pH
chloride
Cl-
balance and charge of sodium and K+ ions in cells
phosphate
PO4 3-
cell membrane formation nucleic acid and ATP formation
hydroxide
OH-
catalyses reactions
calcium
cation
Ca 2+
muscle contractions and nerve impulse transmissions
sodium
Na+
regulates water potential
pottasium
K+
stomatal opening
Hydrogen
H+
regulates/ affect pH
Ammonium
NH4 +
produces nitrate ions by bacteria
Biuret test method and what it tests for
proteins
add 2cm3 of sample and 2cm3 biuret solution to test tube
positive test if goes to purple/lilac
benedict’s test method and what it tests for
reducing sugars
add scm3 sample and 2cm3 benedicts reagent
heat gently in water bath for 2 minute -85c
positive result goes green/brick red precipitate
Non- reducing sugars test
add 2cm3 sample and 1cm3 HCl
boil in water bath 1 min
neutralise with NaHCO3 powder
check pH with indicator paper
carry out benedict’s test
positive result green/brick red precipitate
iodine test method and what it tests for
starch
add 1cm3 to spotting tile
add few drops iodine
positive result goes blue/black
emulsion test method and what it tests for
lipids
add 1cm3 ethanol
add 1cm3 sample and shake vigorously
add 1cm3 cold water
positive test has cloudy emulsion
Rf value equation
distance moved by solute/ distance moved by solvent
glycerol + 3 fatty acids
triglyceride + 3 water molecules
3 hydroxyl groups of glycerol and 3 fatty acid hydroxyl groups react releasing 3 water molecules
ribose
pentose sugar
used to make RNA
deoxyribose
pentose sugar
used to make DNA
difference between ribose and deoxyribose
deoxyribose has 1 less oxygen from the bottom right OH group
Maltose
2 glucose molecules
lactose
galactose and glucose
sucrose
glucose and fructose
makes 1-2 glycosidic bond
