Biological Molecules Flashcards
Bond formed and polymer for
Amino acids
Nucleotide
Monosaccharides
Amino acids - peptide bond, form proteins (polypeptides)
Nucleotide - phosphodiester bond, forms nucleic acids (RNA, DNA)
Monosaccharides - glycosidic, polysaccharides
Constituent elements of
Carbohydrates
Proteins
Lipids
Nucleic acids
Carbs - CHO (more O, less H)
Proteins - CHONS
lipids - CHO (more H, less O)
Nucleic - CHONP
Water is a […] molecule
Polar
Formation of H bonds in water
Properties and roles of water
+ solid ice = less dense than water (l) therefore surface of ice = habitat for organisms
Water beneath ice remains insulated and aquatic organisms don’t freeze to death
Alpha vs beta glucose
3 diff disaccharide we have to know
Maltose
Sucrose
Lactose
Constituents of the 3 disaccharides
a gluc + a gluc -> maltose & water (1,4 bonds)
a gluc + fruc-> sucrose & water (1,2 bond)
a gluc + b galactose -> lactose & water (1,4 bond)
Glycosidic bonds also form where the 2OH groups of separate monosaccharide are adjacent
Carbohydrate function
Energy store, energy source, structural units
Deoxyribose vs ribose
Deoxyribose vs ribose
Reducing vs non-reducing sugars
Starch features & function
Amylose vs amylopectin
Function of cellulose
Main structural constituent of plant cell walls
Features of cellulose
- high tensile strength
- insoluble in water
- flexible
- strong microfibrils
- fibrous
- not granular
Cellulose structure details
-b glucose monomers 1,4 glycoside bonds
Why are branched polysaccharides better for energy storage
- lots of branches for enzymes to attach to
- compact molecules
- high energy content for their mass
- can quickly be hydrolysed
What is glycogen
Main energy storage polysaccharide found in animals and fungi
Why is glycogen better than amylopectin etc
Forms more branches than it so more compact
In animals as it’s Better for storage = more useful for MOBILE animals
Glycogen structure
Lipid characteristics
- macromolecules
- non polar
- have a chain of carbon atoms as a backbone
- insoluble in water
- soluble in alcohol
Saturated vs unsaturated lipids
Unsaturated = double bonds in C=C
Effect of double bond in unsaturated lipids
Causes molecule to bend / kink
So less able to pack tighter nicely, therefore dense
So b.p. Less
How are triglycerides formed from 1 glycerol & 3 fatty acids
Glycerol + fatty acid structure
Functions of triglycerides
What are phospholipids
Modified triglycerides
One fatty acid change replaced by inorganic phosphate ion (PO4)3-
Phospholipids made up of?
And function
Form selective permeable phospholipid bilayer
Made up of 1 glycerol, 2 fatty acids & a phosphate group therefore polar
Phospholipids in water? E.g. how does hydrophobia & philia play a role
What roles of the phospholipid bilayer are there?
Forms the cell membrane,
(which plays a role in Compartmentalisation: to separate the sites of chemical reactions and allow for the formation of concentration gradients)
Separate as the cytoplasm from outer (aq) environments
What are sterols and their function
Roles of lipids
Membrane formation (hydrophobic barrier)
Hormone production
Electrical insulation (neuron myelin sheath).
Waterproofing (birth feathers, plant leaves)
Lipid identification emulsion test steps
- Mix sample with ethanol (if solid should be ground up first)
- Mix solution with water & shake
- If the white emulsion forms @ top, indicator of lipid
General structure of an Amino acid
How peptide bond form
Oligopeptide vs polypeptide
Oligo = short chain of amino acids linked together
Poly = long chain
How many protein structures
4
Protein primary structure
The sequence of amino acids in a polypeptide chain, specific to each protein
Protein secondary structure
Formed due to hydrogen bonds forming between amine group and carboxylic group which leads to the folding into a beta pleated sheet or coiling into an alpha helix
H bond can be broken at high temps & pH changes
Tertiary structure + types of bonds formed in it
The further coiling and folding of the amino acid to form the overall 3D shape of a protein & additional bonds being formed between R groups
Hydrogen - between R groups = weakest bind
Ionic - between pos & neg R groups
Disulfide (strong cov bonds between 2 cysteine R groups (these contain S atoms & can be broken by oxidation)
Weak hydrophobic interactions - between non-polar, hydrophobic R groups, to cause twisting of amino acid chains
Quaternary structure of proteins
Consisting of many polypeptide chains
Contains b and alpha subunits & peptide bonds
The arrangement of 2nor more polypeptide chains in a protein make up its quaternary number
Types of proteins
Globular & fibrous
Globular protein features / structure / function
Examples of globular proteins and what they do
What are conjugated proteins + example
Haemoglobin
Haemoglobic structure & function
Fibrous protein features
3 examples of fibrous proteins?
Keratin
Elastins
Collagen
Keratin function
Provides mechanical protection & is waterproof
Impermeable barrier to infection
Found in nails and hair
Elastins function
Allows stretch and recoil in lungs
+ in blood vessels to maintain blood pressure
Collagen function and structure
Provides mechanical strength:
Withstands arteries high pressure
Tendons & binds made of collagen
Connective tissue
Structure
Every 3rd amino acid = glycine = allows polypeptide chain closeness
Formed of 3 polypeptide chains with H bonds between them, forming a triple helix
Adjacent molecules joined by cross links which are staggered in the ends of fibrils
Give 3 functions of the cytoskeleton
Hold organelles in place
Provide strength & support (not structural)
Movement of chromosomes
