2.2.6-14 biomols - lipids, proteins, inorganic ions Flashcards
lipids are only soluble in …
ORGANIC solvents
saturated lipids
- eg animal fats (solid)
- only c-c single bonds
unsaturated lipids
- eg plant oils (FOREXAMPLE SAY VEGETABLE OIL ) (liquid)
- c=c double bonds
unsaturated lipid melting point
LOWER
- double bond causes a kink in the chain
- molecules cant pack as closely together
- weaker imfs so lower mp
unsaturated lipid state (room temp)
liquid
saturated lipid state (room temp)
solid
triglycerides
lipids made of one glycerol headand 3 fatty acid tails
bond joining glycerol and fatty acids
ester bond
reaction where triglycerides are made
condensation
use of triglycerides
ENERGY STORAGE (plant + animals)
phospholipids
- one fatty acid of a triglyceride is replaced by a phosphate containing group
- glycerolhead, 2 fatty acid chains, 1 phosphate
phosphate head property…
HYDORPHILIC (as it is charged)
tail of phospholipid property
HYDROPHOBIC
hydrogen ion formula
H+
amino group
NH2
how many diff amino acids
20
- differ by their ‘R’ group
bond joining amino acids
PEPTIDE bond
reaction joining amino acids
condensation
primary structure (2)
-order and number of amino acids in a protein
- held together by PEPTIDE bonds
secondary structure
-REGULAR FOLDING of amino acid chain into repeating patterns
- either alpha helix or beta pleated
what bond holds together secondary structure
hydrogen bonding
tertiary structure of proteins
- SECONDARY IS COILED AND FOLDED FURTHER
-disulfide bridge, ionic, hydrogen bonds between R GROUPS !!!!!!!!! - FINAL 3D STRUCTURE OF AMINO ACIDS FROM 1 PPC
globular protein shape
highly folded - spherical
examples of fibrous (2)
- keratin
- collagen
example of globular (3)
- haemoglobin
- insulin
- enzymes
biuret test
- add BIURET
OR - sample + equal amount of NaOH
- add copper (II) sulphate solution and mix
- if positive, blue -> lilac
lipids test
- add ethanol and thoroughly shake
- add water
- if positive, colourless -> milky white
macromolecules
complex molecules with a high mr
lipids elements
carbon, hydrogen, oxygen
why are lipids insoluble in water
hydrophobic tail
break down of triglycerides reaction
hydrolysis
why are triglycerides good for storage (2)
- long HC tails of fatty acids contain lots of chemical energy. lipids contain 2x as much energy per gram as carbohydrates
- insoluble, dont change osmotic conditions.
where are phospholipids found
cell membranes of all eukaryotes and prokaryotes (phospholipid bilayer)
phospholipid bilayer
- phospholipid heads are hydrophilic, and tails hydrophobic, so they form a double layer with their heads facing out towards the water on either side
- centre of the layer is hydrophobic, so membrane is a barrier
cholesterol
4 ring structure
cholesterol size + shape
small size + flattened shape, so cholesterol can fit in-between phospholipid molecules of membrane
dipeptide
2 amino acids join together
amino acid elements
CHON(S)
Quaternary structure
- diff PPC held together by bonds
- the way the chains are assembled together
- eg haemoglobin from 4 PPCS
globular solubility and why
SOLUBLE (so easily transported)
- hydrophilic R groups pushed to the outside, hydrophobic on inside
- forms HB with water
haemoglobin
- globular
- carries oxygen around the body in RBCs
- 2 alpha 2 beta
- conjugated protein; EACH PPC SUBUNIT has a non protein (prosthetic) group attached - 4 prosthetics
- called, haem, which contains the single Fe2+ ion that oxygen binds to
are lipids polymers
NO
are lipids soluble
NO
- dont affect cell water potential , or osmosis
Lipid purposes (7)
- thermal insulation (blubber)
- electrical insulation (myelin sheath)
- energy store
- protection of organs (waxy cuticle, fat)
- cell membranes (phospholipid bilayer)
- steroid hormones (eg testosterone)
- source of water (respiration)
why do camels store fat in their humps
- lipids can be broken down in aerobic respiration to release energy
- creating water
blubber provides (2)
- warmth
- buoyancy
bonds holding together amino acids in primary structure
peptide bonds
what bonds hold secondary structures together
Hydrogen bonds
bonds holding tertiary structures together
- HBs between polar R groups
- ionic bonds between R groups
- covalent disulphide bonds between two R groups with sulfur
fibrous solubility
insoluble
few hydrophilic groups
fibrous level of structure
quaternary
why are fibrous strong
bonding between polypeptide chains
collagen structure (6)
CHON
- peptide bonds between amino acids
- every 3rd amino acid is glycine
- 3 PPCS
- h bonds between chains
- adjacent chains form covalent bonds (crosslinks) which are staggered to avoid weak points
- insoluble, as few hpi groups on outside
collagen uses (4)
- artery walls to withstand high BP
- tendons
- bones
-cartilage
keratin structure
2 PPCS
NH4+ (2)
- nitrogen cycle
- maintains pH
Ca2+ (3)
- blood clotting
- activates enzymes
- stimulates muscle contraction
why not do emulsion test on something cloudy
cant see If result is positive or not
why do lipids release lots of energy
high energy: mass ratio , so high calorific value from oxidation
lipids insolubility advatanges (2)
- waterproofing
- no effect on WP of cells
lipids conduction of heat
slow
thermal insulation
lipids buoyancy of animals
less dense than water
elastin uses
- elasticity to connective tissue
- arteries, skin, lungs etc
what is buret made of
sodium hydroxide + copper sulfate
NO3-
- DNA + amino acids
OH-
- maintain pH
- cause denaturation
PO43-
- DNA
hydrocarbon tail solubility
INSOLUBLE
Hydrophobic
number of waters formed for each triglyceride
3
how to triglycerides clump together
in DROPLETS
Hydrophobic carbon tails face out
cholesterol role
- reduces fluidity of **eukaryotic **cell membranes
- phospholipids more tightly packed so membrane is more rigid
all steroid hormones are derived from
cholesterol
how does a phospholipid differ to triglyceride
one of the 3 fatty acid chains is replaced by a phosphate molecule
‘R’ group significance
- variable group
- gives amino acid its specific characteristics
are enzymes globular or fibrous
globular
sulfer atoms needed for …
proteins
Conjugated protein defintion
- has a non protein
- prosthetic group
-attached by covalent bonds - specify what it is (eg fe2+)
how many prosthetic groups in haemoglobin
4
properties of fibrous (4)
- little tertiary structure - ELONGATED
- insoluble
- small range of amino acids
- STRONG
- flexible
- structural (collagen)+protective (keratin) functions
WHY is collagen so strong
- hydrogen bonds
- cross links [covalent bonds]
cytseine special feature
SULFUR - disulfide bridge
chromatography comparison (4)
- blots of the 2 samples
- separate with a solvent
- NINHYDRIN stain to see spots
- compare patterns
describe peptide bond
between AMINE group and CARBOXYL group of adjacent amino acid
4 key features of collagen
- high tensile strength
- inelastic
- insoluble
-flexible
suggest how plasmodium releases amino acids from haemoglobin
- hydrolysis
- by enzymes (proteases)
- peptide bonds broken
explain how the structure of phospholipids allows them to form the bilayer of a plasma membrane? (5)
- hydrophilic phosphate head and hydrophobic fatty acid tails
-hydrophobic tails are repelled by water - hydrophilic head forms H bonds with water
- MEDIUM OUTSIDE MEMBRANE IS AQUEOUS
-hydrophobic tails mean they face towards each other
circle ester bond
both O atoms and the C between them
density of lipids v proteins
lipids are less dense than proteins
bile is made of
cholesterol
hydrolysis of triglycerides
- use of water
- to break 3 ester bonds
- forming glycerol + 3 fatty acids
enzyme’s biuret
- positive
- is possible because enzymes are globular so soluble
similarities in phospholipids and triglycerides?
- contain glycerol
- fatty acids
- ester bonds
- C,H,O
PEPTIDE BOND ATOM FORMATION
H from amine with OH from carboxyl
test solid for proteins
- crush a small amount
- add biurets
- blue to lilac
collagen atoms
C,H,O,N
crosslinks in collagen
- covalent bonds between the 3 adjacent molecules
- staggered at the end of molecules to avoid weak points
how to know if its unsaturated with just molecular formula
LOWER RATIO of hydrogens to oxygens
what type of bond is a peptide bond
COVALENT
globular proteins temperature
very sensitive
shape easily distorted
amylase ion
calcium ion
insulin
- fixed specific shape
- 2 PPCs with disulphide bridges
- soluble
ammonium (3)
- amino acids
- nitrogen cycle
-pH
ca 2+ (2)
- blood clotting
- activates enzymes
h+
- regulation of blood pH
- transport of CO2 in blood
fe2+
increases affinity of haemoglobin for oxygen
na+
- regulation of water potential in cells and bodily fluids
- reabsorption of water in kidney
mg2+
chlorophyll
k+
- growth of leaves and flowers
- regulation of water p in cells and bodily fluids
cl-
- reabsorption of water in kidney
- production of HCl in stomach
HCO3-
- regulation of blood pH
- transport of co2 in blood
OH-
regulation of blood pH
no3=
- nitrogen cycle
- amino acids, proteins, nucleic acids
po43-
- component of phospholipids and atp
globular properties
- soluble
- spherical
- HAVE 3D TERTIARY STRUCTURE
- temperature+pH sensitive
- metabolic role (enzymes), transporting substances (haemoglobin)
cholestrol at different temperatures
- INCREASES fluiditiy at low temperatures
- DECREASES fluiditiy at high temperatures
collagen role
bones and cartilage
walls of BV
elastin role
- stretch and recoil
- eg walls of BV
keratin role
protecive, in hair and nails
