Biological Molecules Module 2 Flashcards
What is a monomer
Small repeating units from which larger molecules are made
What is a polymer + eg
Molecules made from lots of monomers eg protein (amino acids), monosaccharides (sugar),
How do you join and separate monomers
Hydrolysis: breaking using water
Condensation: 2 monomers join giving water out, forms covalent bond
Properties of water
Specific heat capacity
Latent heat
Cohesion
Adhesion
Type of bond and what molecule is water
Polar molecule, hydrogen bonds
What are carbohydrates + what do they contain
Contain carbon hydrogen oxygen
Known as sacchrides , polysaccharides, monosaccharides
What are polysaccharides + the egs
Many monomers linked by glycosidic bonds formed by condensation reactions
Eg: starch, cellulose, glycogen
Blurt cellulose (polysaccharide)
In the cell wall of plant ,
Abundant + organic
Beta glucose molecules joined by beta 1-4 glycosidic bonds
Very strong, rope structure
Blurt glycagen (polysacchride)
Made of glucose
Similar structure to amylopectin
Alpha 1-6 glycosidic bond that provides branched structure
Stored as small granules in liver, muscle
Less dense
Soluble
Breaks down faster (high metabolic rate)
1-4 horizontal 1-6 branched
Blurt starch (polysaccharide)
Insoluble
In plants
Alpha glucose
Structural units: amylopectin, amylose
Amylose: spiral structure, alpha 1-4 glycosidic bond, compact, coils
Amylopectin: branched with 1-6 alpha so molecule can be released easily (1-6 accessible to enzyme).
Explain triglycerides (fatty acids) - lipids
Saturated
Glycerol attached to 3 fatty acids
Glycerol is a 3 carbon based molecule
OH (hydroxyl) group bonded to each 3 carbon
Fatty acids is carboxylic (-COOH) and attached to hydrocarbon chain
What is an Esther bond (triglyceride/lipids)
Formed by condensation reaction between each of 3 OH groups on glycerol + OH group pf each fatty acids
Explain phospholipids
Found in cell membrane
Make ‘bilayer’ structure
One fatty acid molecule replaced by phosphate group - group is hydrophilic and fatty acid tails are hydrophobic
Use of lipids
Long term energy store
Thermal insulation
Insulate nerve axons
Protect organs
Hormones
What are lipids
Macromolecule - not polymer as subunits can’t repeat indefinitely
Contain carbon, hydrogen, oxygen
Insoluble in h20
Saturated fatty acids = no double bond between C
Monounsaturated fatty acids = one double bond
Polyunsaturated = more than 1 double bond between C in hydrocarbon chain
What’s a polypeptide
When amino acids are added to dipeptides
Type of protein
Primary structure in protein
simple long chain with no intramolecular bonds or interactions only peptide bonds
Secondary structure of protein
Hydrogen bonds form so molecule folds/coils
Tertiary structure of protein
Hydrophilic/hydrophobic interactions, hydrogen bonds ionic bonds and disulphile bonds hold molecule together
Quaternary structure of protein
Hydrophilic + phobic interactions, hydrogen, ionic, disulphide bonds and 2 or more separate polypeptide chains interlinked
What’s a disulphide bond
Strongest type of bond and between 2 cysteine amino acids and only present if sulphur is present
What’s a peptide bond
Formed in between individual amino acids molecule
Protein blurt
Made up of amino acids
It’s the main component of body tissue eg muscle
Biological catalyst
Hormones, receptors, antibodies all proteins
Formed by condensation reaction
Shape of protein
3 dimensional shape in 2 categories: globular (ball/compact), soluble (hydrophobic ‘r’ group inward and hydrophilic ‘r’ group outside
Fibrous (repeating sequence of amino acid) usually insoluble
Haemoglobin protein eg
Globular, transport O2, made of 4 polypeptide 2 alpha chain 2 beta chain, tertiary, soluble in h2o, has non protein haem group with iron ion
Insulin protein eg
Globular, peptide hormone released by pancreas, maintains blood glucose levels made of 2 polypeptide chains (A+B) tertiary, joined by disulphide bonds soluble in water
Pepsin protein eg
Globular, protease enzyme, made in stomach to digest, single polypeptide chain with symmetrical tertiary structure held together by hydrogen bonds + 2 disulphide bridges, stable in acidity as few groups accept H+ ions
Collagen protein eg
Fibrous amino acid bonded by polypeptide bond
Made of 3 intertwined alpha helix
Every 3rd amino acids in polypeptide chain is glycine as it allows it to close
Supportive tissue
Elastin protein eg
Fibrous
Found in skin where it allows it to stretch/change shape
Cross linking so it’s strong
Keratin protein eg
Fibrous
Found where body needs to be hard
Mechanical protection
Impermeable barrier to infection + water
Lots of cysteine so disulphide bridges between peptide chains
Hydrogen bonding
