t1 bio mols Flashcards
what is a monomer
smaller, repeating unit from which larger polymers are made
what is a polymer
large mols made from many repeating monomer units joined together in a chain (polymerisation)
what is a condensation reaction + example
monomers joining together with the removal of a water mol
eg monosaccharides condense to form a polysaccharide
what is a hydrolysis reaction + example
breaking of chemical bonds between 2 mols to split a polymer to its constituent monomers w the addition of water
eg. polysaccharides hydrolyse to form monosaccharides
what kind of bonds join carbohydrates
glycosidic bonds between 2 hydroxyl -OH groups - formed in condensation reactions
def + examples of reducing sugars
sugars that can donate electrons
-glucose
-fructose
-galactose
def + example of non-reducing sugar
sugar cant donate electrons
-sucrose
properties of monosaccharides
-white, crystalline solids at room temp
-soluble in water
-sweet
-all are reducing sugars
test for reducing sugars
- add benedicts (blue)
- BOIL in water bath
- Brick red colour (can be on scale depending on conc)
maltose =
glucose + glucose
sucrose =
glucose + fructose
lactose =
glucose + galactose
test for non-reducing sugars
- add dilute HCl
- BOIL in water bath
- neutralise w sodium hydrogen carbonate. test pH
- add benedicts and BOIL
- blue to brick red
structure of starch
2 long alpha glucose chains:
1. Amylose -
- unbranched, helix-shaped chain wound into coil
-1,4 glycosidic bonds
- Amylopectin -
-branched chain - easy hydrolysis for resp
-1,4 and 1,6 glycosidic bonds
test for starch
- add orange/brown iodine in potassium iodide solution
- blue black
structure of glycogen
- alpha glucose chains
-1,4 glycosidic bonds
-highly branched - compact, easily hydrolysed
structure of cellulose
-beta glucose
-1,4 glycosidic bonds
-every other monomer is INVERTED
-H bonds form between chains increasing strength
structure of trigylcerides
- 3 fatty acid chains and 1 glycerol
- ESTER bond between hydroxyl group (on glycerol) and carboxyl group (on fatty acids)
- can be saturates (NO double C bonds) or unsaturated (HAS double C bonds)
functions of triglycerides
-source of energy: high ratio of energy-story C-H bonds, release energy used to produced ATP when oxidised
-storage mol - low mass to energy ratio
-insulation - part of myelin sheath around nerve fibres and part of blubber in whales
structure of phospholipids
-glycerol, 2 fatty acid chains, phosphate mol
-ESTER bond
-hydroPHOBIC tails
-hydroPHILIC heads
functions of phospholipids
-form cell-surface membranes (phospholipid bilayer) - barrier between inside and outside of cell - allows diff conditions
-contribute to fluidity of membrane - mainly saturated fatty acids = less fluid
-form micelles when in contact w water
test for lipids
-emulsion test
1. add ethanol to sample and shake to dissolve lipids
2. add to water and shake gently
3.cloudy-white emulsion forms on top = pos result
structure of amino acids
- amine group (NH2)
- carboxyl group (COOH)
- hydrogen atom
- central C atom
- variable R group - every amino acid has diff chemical on R group
primary structure of proteins
-sequence of amino acids determined by DNA
-mutations can lead to beneficial new features
secondary structure of proteins
-proteins can form 2 shapes: alpha helix or beta pleated sheet
-determined by type of H bonding that occurs
tertiary structure of proteins
-now functional
-3D shape formed from further folding
-bonds form to maintain structure:
1. disulphide bridges - between sulphur in R groups
2. hydrogen bonds - numerous and easily broken
3. ionic bonds - between carboxyl and amine groups that arent involved in peptide bonds
quaternary structure of proteins
-more than 1 tertiary protein chain joined together
-may contain prosthetic (non-protein) group eg. Haemoglobin has iron ions
test for proteins
- add biurets solution (sodium hydroxide and copper sulphate)
- blue to purple =pos result
2 basic types of protein
- globular - metabolic function - eg. haemoglobin, enzymes
- fibrous - structural function - eg. collagen in skin
structure of enzymes
-globular proteins
-have functional active site that forms small depression within larger enzyme mol
-active site has relatively low no of amino acids
function of enzymes
-act as catalysts - increase RoR without undergoing permanent changes themselves
-can be used repeatedly so are effective in small amounts
induced fit model
-when specific enzymes and substrates bind, the enzyme changes shape so that they can form an enzyme-substrate complex
-it does this by breaking bonds in the enzymes tertiary structure during the distortion of the active site
how do enzymes increase RoR
-when the enzyme changes shape as an enzyme-substrate complex forms (induced fit model), the bonds in the enzymes tertiary structure break
-this LOWERS activation energy
-increases RoR as it takes less energy for reactions to occur
4 factors affecting rate of enzyme-controlled reactions
- temp
- pH
- enzyme conc
- substrate conc
how does temp affect RoR
-RoR increases up to the optimum temp
-Ek of the enzyme increases, increasing collisions w the enzyme active sites
-above optimum temp, RoR slows as enzymes become denatured. below optimum temp, RoR slows as Ek is decreased
how does pH affect RoR
-pH of solution is measure of hydrogen ion conc
-enzymes have an optimum pH - become denatured at extremes of pH
-below or above optimum, solutions w an excess of H+ or OH- ions can cause the H and ionic bonds that hold the tertiary structure of enzymes together to break, altering the shape of the active site
how does enzyme conc affect RoR
-higher enzyme conc increases RoR - greater no of active sites and greater likelihood of enzyme-substrate complex formation
-as long as there is sufficient substrate conc, RoR increases proportionally to enzyme conc
how does substrate conc affect RoR
-higher substrate conc increases RoR up to a point (if enzyme conc is fixed)
-will reach a point where all active sites are full and RoR will plateau
competitive enzyme inhibitors
-have similar shape to that of substrate mols so can fit into active sites and prevent actual substrate mols from forming enzyme-substrate complexes
non-competitive enzyme inhibitors
-bind to allosteric site (any site that isnt active site), changing shape of whole enzyme and indirectly distorting active site, preventing enzyme-substrate complexes being formed
-if only slight change occurs, activation energy may just be increased
effect of adding more substrate on competitive enzyme inhibitors
-effect of competitive inhibitors decreased - substrate more likely to collide w active site and form enzyme-substrate complex
effect of adding more substrate on non-competitive enzyme inhibitors
-effect of non-competitive inhibitors is constant, even if more substrate is added
-shape of active sites remains changed and enzyme-substrate complexes are still unable to form
calculating pH equation
pH = -log₁₀ [H⁺]
role of hydrogen ions
-lower pH of substances (make them more acidic)
-can regulate pH of body fluids to enable enzyme activity
role of iron ions
-component of haemoglobin that transports oxygen
-involved in transfer of electrons during photosynthesis and respiration
role of sodium ions
-involved in co-transport of glucose and amino acids.
-have role in generating action potentials
role of phosphate ions
-component of DNA, RNA and ATP
-increase reactivity of ADP
-found in phospholipids in cell membranes
name the inorganic ions (brief)
- hydrogen
- sodium
- iron
- phosphate
properties of water (brief)
-dipole (2 different charges)
-metabolite
-solvent
-high specific heat capacity
-high latent heat of vaporisation
-high surface tension
-high cohesion = capillary action
structure of ATP
-adenosine triphosphate
-Adenine, ribose and 3 phosphate molecules
role of ATP and 4 processes it is involved in
-energy-carrying mol that provides constant supply of immediate energy to drive processes such as:
1. anabolic reactions
2. active transport
3. energy for muscle contraction
4. conduction of nerve impulses
hydrolysis of ATP
-terminal phosphate is removed and remaining molecule becomes ADP.
-removed phosphate called Inorganic Phosphate (Pi).
-reaction catalysed by ATP hydrolase
-bonds between P groups are unstable so have low activation energy and are easily broken
-release large amount of energy when bonds are broken
synthesis of ATP
-ADP combined w an inorganic phosphate (Pi)
-catalysed by enzyme ATP synthase in condensation reaction that requires energy
-made during respiration and photosynthesis
-can also be made when P groups are transferred from donor molecules (substrate-linked phosphorylation)
what did Watson and Crick come up w
-semi-conservative DNA replication theory
what did Meselsohn and Stahl prove
-Watson and Crick’s semi-conservative DNA replication theory
how was semi-conservative DNA replication proven
- labelled original DNA mol by growing it on medium of Nitrogen-15 (heavier)
2.transferred bacteria to medium of Nitrogen-14 and allowed single gen to replicate
3.spun new DNA in centrifuge to determine mass - if semi-conservative rep had taken place, all DNA mols would contain both heavy N-15 and light N-14 and would settle in middle of tube
what is semi-conservative DNA replication
-only 1 strand is newly made and the other is pre-existing and acts as a template for the other strand to be formed (due to base pairings)
-ensures genetic continuity between gens of cells to make sure they can perform same role as parent cell
process of semi-conservative replication
- enzyme DNA helicase breaks H bonds between bases and separates strands
- each exposed polynucleotide strand acts as a template for new complementary free nucleotides to bind to specific base pairing
- enzyme DNA polymerase joins strands together in condensation reactions
- each new DNA mol contains one strand from parent and 1 new strand (half of DNA has been conserved)
RNA structure
-phosphate group, ribose, nitrogenous base (Adenine, Cytosine, Guanine, Uracil)
-single stranded polynucleotide w nucleotides joined by phosphodiester bonds
-bond is between ribose sugar of 1 nucleotide and phosphate group of next
what are the 3 types of RNA (brief)
- messenger RNA (mRNA)
- transfer RNA (tRNA)
- ribosomal RNA (rRNA)
DNA properties and adaptations
-extremely stable due to phosphodiester backbone protecting chemically reactive bases inside double helix - means DNA rarely mutates and can copy info from gen to gen w minimal change
-H bonds link base pairs, meaning strands are easy to break during replication/protein synthesis
-large mols so can carry huge amounts of info
what are purines + example
-make 2 H bonds
-double ringed structures
-adenine and guanine
what are pyrimidines + examples
-make 3 H bonds (more stable)
-single ringed structure
-thymine, cytosine and uracil
DNA structure
-phosphate group, deoxyribose and a nitrogenous base (adenine, guanine, cytosine, thymine)
-nucleotides joined by phosphodiester bonds between sugar and phosphate group
-sugar and base joined by glycosidic bonds
-strands run in opposite directions (antiparallel)
