module 1 Flashcards
ATP
a molecule that acts as the energy currency of cells formed from a molecule of ribose, a molecule of adenine and 3 phosphate groups
amino acid definition
the monomers containing an amino group (NH2), a carboxyl group(COOH) and variable R group that makes up proteins
benedicts test
a biochemical test used to test for reducing sugars that produce a different colour based on the amount of reducing sugar present
biuret test
a biochemical test that produces a purple solution in the presence of protein
what are biological molecules
molecules made and used by living organisms e.g carbohydrates,proteins,lipids,DNA,ATP
what are the functions of carbohydrates
energy source ( glucose in respiration)
energy store( starch in plants,glycogen in animals)
structure ( cellulose in cell wall of plants)
what are the building blocks for carbohydrates called
monosaccharides
examples of monosaccharides
glucose (alpha and beta) galactose , fructose
formula of monosaccharides
C6H12O6
difference between alpha and beta glucose
on carbon 1, alpha glucose has an OH group on the bottom and beta glucose has OH group on the top
how are monosaccharides joined together
condensation reaction between 2 OH groups
water is removed
bond in carbohydrate
glycosidic bond ( 1,4)
examples of disaccharides ( the equations)
glucose+ glucose= maltose
glucose+ galactose= lactose
glucose+ fructose= sucrose
formula for disaccharides
C12H22O11
how are polymers separated
hydrolysis
add water
what is a polysaccharide
many monosaccharides joined together by condensation reaction/glycosidic bonds
examples of polysaccharides
starch(alpha glucose) which is an energy store in plants
glycogen(alpha glucose) which is an energy store in animals
cellulose(beta glucose) which makes cell wall in plants
structure of starch
made from amylose and amylopectin
what is amylose
long straight chain of alpha-glucose which is coiled
what is amylopectin
straight chain of alpha-glucose which side branches ( 1,6 glycosidic bonds)
structure of glycogen
straight chain of alpha-glucose( ,4 glycosidic bond) with side branches (1,6 gb)
properties of starch and glycogen as energy stores
insoluble= do not affect water potential of the cell, do not diffuse out of the cell
coiled/branched= compact, more can fit into a cell
branched/chained= glucose removed from the end easily
structure of cellulose
beta glucose arranged in a straight chain
many cellulose chains are cross linked by hydrogen bonds to form microfibrils
many microfibrils are cross linked to form macrofibrils
forms structure of cell wall
strong material ( to prevent plant cell from bursting or shrinking
test for starch
add iodine, turns blue/black
test for non-reducing sugar
heat with benedicts- no change
therfore add dilute HCL ( hydrolyses glycosidic bond)
then add sodium hydrogencarbonate to neutralise
heat with benedicts again - turns brick red
what are 2 types of proteins
globular and fibrous
what are globular proteins
soluble proteins with a specific 3D shape
eg enzymes, hormones, antibodies, haemoglobin
what are fibrous proteins
strong , insoluble ,inflexible material
eg collagen and keratin
what are the building blocks for proteins
amino acids
structure of amino acid
central carbon, carboxyl group to right, amine group to left, hydrogen above and r group below
how do amino acids differ
they have different R groups
how are amino acids joined together
by condensation reaction between the carboxyl group of one and amine group of another, leaves a bond between carbon and nitrogen called a peptide bond forming a dipeptide
define primary structure of a protein
sequence of amino acids in a polypeptide chain held together by peptide bonds
define secondary structure of a protein
the primary structure coils to form either a alpha helix or beta pleated sheets held together by hydrogen bonds
tertiary structure of a protein
secondary structure folds again to form final 3D shape, held together by hydrogen, ionic, disulphide bonds
quaternary structure of a protein
made of more than one polypeptide chain
examples of quaternary protein structure
collagen , antibodies and haemoglobin
structure of collagen
strong material, used to build tendons/ligaments/connective tissues
primary structure mainly made of glycine
secondary structure forms a tight coil (not much branching due to glycine)
tertiary structure( coils again)
quaternary structure made from 3 tertiary wrapped around each other
what is an enzyme
a biological catalyst, a substance that speeds up the rate of reaction without being used up by lowering the activation energy and offering an alternate pathway
what makes enzymes specific
has specific active site shape, only complimentary substrates can bind to form enzyme-substrate complexes
lock and key model vs induced fit model
LK= active site shape is rigid and only exactly complimentary substrates can bind to form ES substrates
IF= active site changes shape slightly, the substrate binds to the active site- the AS changes shape so the substrate fits exactly forming ES complexes
affect of substrate conc on enzyme activity
increase substrate conc increases the chance of successful collisions which increases the chance of forming an ES complex which increases the rate of reaction
this continues untill all the enzymes active sites are full/saturated = the maximum rate of reaction
affect of enzyme conc on enzyme activity
increases chance of successful collisions increases chance of ES complexes forming so an increase in rate of reaction
continues until all substrates are used up= maximum rate of reaction
affects of temperature on enzyme activity
as temp increases kinetic energy also increases meaning the molecules move faster , more successful collisions, more ES complexes , increasing rate of reaction
carries on until optimum, then bonds in tertiary structure breaks ( hydrogen and ionic) so active site looses shape , substrates no longer complementary so ES complexes arnt made
enzymes denatured
affects of PH on enzyme activity
if change in PH away from optimum bonds in the tertiary structure break so active site looses shape = no ES complex
enzyme denatured
competitive inhibitors
a substance with a similar shape to the substrate and a complementary shape to the enzymes active site, binds to the active site, blocking it, prevents ES complexes from forming
non-competitive inhibitors
a substance that binds to another site on the enzyme other then the active site, causes the active site to change shape, so less ES complexes can form
what are the 3 types of lipids
triglycerides ( fat for energy store,insulation, protection of organs)
phospholipids ( to make membranes)
cholesterol ( for membrane stability and make hormones)
structure of triglycerides
made of 1 glycerol and 3 fatty acids
joined by condensation reaction, ester bonds
bond is COOC
there are 2 types of triglycerides: saturated fat and unsaturated fat
saturated
has no carbon double bonds in the r group
unsaturated
has carbon double bonds in the r group
structure of phospholipid
made of 1 glycerol , 2 fatty acids and 1 phosphate
phosphate forms hydrophillic head, fatty acid form hydrophobic tails
forms a phospholipid bilayer basic structure of membranes
what are nucleic acids
polymers made from nucleotides
( 2 types DNA and RNA )
what is DNA
an information storing molecule made of dna monomers joined by phosphodiester bonds to form a double alpha helix
deoxyribonucleic acid
found in all organisms
carries genes
all organisms are built of proteins
building block of DNA
DNA nucleotide ( made of phosphate, deoxyribose sugar, nitrogenous base)
4 types of nucleotides( adenine , thymine, cytosine , guanine)
properties of DNA structure
double stranded= makes DNA more stable and strand acts as template in semi-conservative replication
coil in helix= more compact
sugar phosphate backbone= protects bases
h bonds = weak so strands separate more easily
complimentary base pairing= ensures identical copies of DNA made by semi-conservative replication
DNA replication
occurs in interphase before mitosis and meiosis
occurs by semi-conservative repliction
describe semi-conservative replication
DNA double strand separates and acts as template producing 2 identical copies of the dna, each has half the orginal strand and half the new strand
PROCESS:
dna helicase breaks h bonds between bases
double strande separates, leaves 2 template strands
free complimentary nucleotides bind to exposed bases on tmeplate strands
DNA polymerase joins the sugar-phosphate backbone of the new strand
evidence for SCR
replicating bacterial DNA in 2 types of nitrogen isotopes, 15N and 14N
what is rna
ribonucleic acid
a relatively short molecule made up of ribonucleotide monomers joined by phosphodiester bonds
single stranded
bases = Adenine, uracil , cytosine, guanine
formation of ATP ( equation)
ADP + PI = ATP
carries energy in its bonds
what makes ATP good to deliverer of energy
immediate source= need to only breakdown one bond and that bond is weak
manageable source= releases small amount of energy
uses of ATP in organisms
protein synthesis, organelles synthesis, DNA replication, cell division (mitosis), active transport, metabolic reactions, movements, maintaining body temerature
role of water in biology
found in living organisms = cytoplasm ( all organisms) , xylem/phloem( in plants), tissue fluid and blood( for animals)
also acts as habitats for living organisms
properties of water
water molecules are dipolar
hydrogen has slightly positive and oxygen is slightly negative
therefore water can form hydrogen bonds with each other
what are inorganic ions
salts/ minerals
inorganic= do not contain carbon
eg sodium ions, chloride ions
water in living organisms - habitat
water had a high specific heat capacity meaning that a lot of heat needs to be aplied before it evaporates due to the h bonds
also when water freezes it forms ice, as ice is less dense than water it floats insulating the water below it ,
in both cases water remains liquid to provide a habitat
water in living organisms- solvent
because water molecules are dipolar they can separate out solutes based on their charge, so solute mixes with water and becomes dissolved, this is useful in cytoplasm of all cells and supports the reaction of these solutes, also useful in the processes of diffusion/active transport, and is also useful in transport such as blood phloem
water in living organisms- hydrostatic pressure
water when pressurised can provide a strong physical pushing force. used particularly in mass flow.
also helps keep turgidity in plants
water in living organisms- - homeostasis
mammals and humans control body temp by sweating, sweat on the skin uses heat from the blood to evaporate , hence, cooling the individual. because sweat/water is made up of hydrogen bonds, it has a stable structure, so requires large amounts of heat for it to evaporate. this is called LATENT HEAT OF VAPORISATION
