Topic 1 Biological molecules Flashcards
what are three examples of monomers
amino acids, monosaccharides, nucleotides
what are the two isomers of glucose
Alpha and Beta
what happens during a condensation reaction
monomers are joined together to make polymers
what happens during a hydrolysis reaction
polymers are broken down and turn back into monomers
name three monosaccharides
glucose, fructose, galactose
what are the three disaccharides
maltose sucrose lactose
monosaccharides that make maltose
glucose + glucose
monosaccharides that make sucrose
glucose + fructose
monosaccharides that make lactose
glucose + galactose
what are the bonds formed between monosaccharides
glycosidic bonds
what does the condensation of amino acids form
proteins
what does the condensation of two monosaccharides produce
disaccharides
what do many disaccharides produce
polysaccharides
what is hydrolysis
what does it require
what does it produce
- the reaction that breaks down large biological molecules
- the reaction requires water
-splits larger molecules into its smaller components
what does the condensation of fatty acids and monoglycerides form
lipids
what is a benefit of hydrolysis?
smaller molecules produced can easily diffuse into cells or be transported using protein channels
what does the hydrolysis of proteins produce
amino acids
hat does the hydrolysis of disaccharides produce
monosaccharides
what does the hydrolysis of lipids produce
fatty acids and monoglycerides
what differs phospholipids to other triglycerides
phospholipids consist of two fatty acids and a phosphate group instead of three fatty acids attached to glycerol
what do phospholipids form when they submerged into water
micelles
what are the two subtypes of fatty acids
saturated and unsaturated
what structure would a saturated fatty acid have
only single car carbon bonds
what is a physical property of saturated fatty acids
tend to be solid and room temp
trait of the structure of unsaturated fatty acid
have at least one double carbon bond
name given to a fatty acid with more than one double carbon bond
polyunsaturated acid
property of unsaturated fatty acids
tend to be liquid at room temp
what are some vague functions of lipids 4 points
protect vital organs
prevent evaporation of water in plant (waxy cuticle)
insulates the body
myelin sheath around some neurons
define non polar
has no overall charge
define hydrophobic
repels water therefor does not dissolve in it
what are the three main components of triglycerides
fatty acids
glycerol
ester bonds
why are lipids containing many unsaturated fatty acids liquid at room temperature
because the unsaturation causes kinks in the straight chains so that the fatty acid chains do not pack closely together
why do lipids have such a high energy content
high ratio of C-H bonds
what is esterification
the formation of a triglyceride from one glycerol and 3 fatty acids in 3 condensation reactions eliminating three molecules of water
what are triglycerides
a type of lipid
what is the structure and properties of triglycerides
non-polar
high ratio of CH bonds (lots of energy stored in them)
hydrophobic
low mass to energy ratio (therefor good for storage)
what are phospholipids
modified triglycerides that are important in the formation of cell membranes
what is the structure of phospholipids that allow them to form a phospholipid bilayer
the head/phosphate end is (hydrophilic) whereas the tail is hydrophobic is hydrophobic
when the molecule comes in contact with water the hydrophobic ends turn inwards in the membrane to form a phospholipid bilayer
term for having both hydrophobic and hydrophilic ends
amphipathic
relate the structure of phospholipids to their chemical properties and their functional role in cellular membranes
.they are amphipathic
.form a bilayer where the hydrophilic heads face outwards making soluble molecules unable to pass through a membrane
how does the cell membrane of an arctic fish differ from a tropical fish
.arctic fish will have an increased amount of unsaturated fatty acids to prevent the cell membrane from becoming too rigid
what type of proteins do all enzymes have and what does this mean
globular proteins
they are highly folded and soluble in water
what monomers are proteins made out of
amino acids
what are the 5 general structures present in proteins
A central carbon atom
An amino group (-NH2)
A carboxyl group (-COOH)
A hydrogen atom (-H)
An R group or a variable side group
what is the test for proteins and describe
.biuret test
.add equal volume of biuret solution
(sodium hydroxide and copper sulphate) to the sample solution
.colour change from blue to lilac indicates positive results
what happens during a hydrolysis reaction
process where a water molecule is added to a dipeptide and the peptide bond is broken to release two amino acids
what is a dipeptide
a molecule formed from two amino acids that are joined by a peptide bond
what happens during a condensation reaction with two amino acids
the hydroxyl (OH) in the carboxyl group of one amino acid reacts with the hydrogen (H) in the amino group of another amino acid
to form a peptide bond between the carbon of one amino acid and the nitrogen of another
what is the name for the resulting chain of many hundreds of amino acids
polypeptide
what is the primary structure of any protein
the sequence of amino acids in a polypeptide chain formed via polymerisation
what does the primary structure of a protein determine
determines the its ultimate shape and hence its function
what is the secondary structure of a protein and why is this because of the hydrogen bonds shared
the shape that the chain of amino acids makes (either alpha or beta pleated sheet)
Hydrogen in the -NH has a slightly positive charge whereas oxygen in the -C=O bond has a slight negative
resulting in weak hydrogen bonds to form into either alpha or beta
what are the three main monomers learnt
amino acids
nucleotides
monosaccharides
what polymer do amino acids make
protein
what polymer do nucleotides make
DNA
what 3 polymers do monosaccharides make
starch
glucose
cellulose
benefit of hydrolysis
breaks larger molecules into smaller ones that can easily diffuse into cells or be transported using protein channel
what does hydrolysis of carbohydrate produce
disaccharides and monosaccharides
what does hydrolysis of lipids produce
fatty acids and monoglycerides
benedict’s on non-reducing sugars
.non reducing sugars will show negative result (sucrose is non-reducing)
.boil and add HCL to hydrolyse the non-reducing sugar
.neutralise the solution with sodium hydrogen carbonate
.repeat benedict’s
.colour change shows presence
what does ATP stand for
adenosine triphosphate
(brief) role of glucose during respiration
during cellular respiration energy released from glucose helps to make adenosine triphosphate
4 brief functions of starch
.main energy storage material in plants
.starch is stored in the seeds of plants
.broken down into glucose by plants when more energy is needed
.starch can act as a source of food for humans and animals
why is energy stored as starch and not glucose in plants
-it is insoluble in water and so does not effect the water potential in a cell
-is compact allowing for more energy to be stored
what is the test for starch and describe
the iodine test
.add few drops of iodine solution into sample and observe colour change
.change from orange to blue-black indicates starch presence
what two polysaccharides make starch
amylopectin and amylose
features of amylopectin
.has a long branched structure
.this makes it ideal for quick energy release
feature of amylose
.a long unbranched helical structure
.making it ideal for storage
how is glycogen formed
by the condensation reactions of alpha-glucose molecules
main function of glycogen and why is it suited for this
.main energy storage material in animals
.it is a compact and highly branched molecule (similar to amylopectin)
.when animals need to release its structure makes it easy for glucose to be quickly released
what is glycogenolysis
process of glycogen being broken down to release glucose when blood glucose levels decrease
3 points on cellulose structure
.is a long chain of beta-glucose
.beta-glucose molecules are linked by glycosidic bonds to form linear cellulose chains that are unbranched
.microfibrils are strong fibres that are made of many cellulose chains that are held together by hydrogen bonds
what is the function of cellulose and why are they best suited
.acts as a major component of cell walls that offer structural support (because of the strength of the microfibril fibres that they are made out of)
what are the two types of starch, their structure and therefore what they are good at
amylose-unbranched-good for energy storage
amylopectin-branched-good for quick energy release
what three elements form carbohydrates
hydrogen
carbon
oxygen
what are triglycerides
a type of lipid mainly used as energy storage molecules
how are triglycerides formed
condensation of 1 molecule of glycerol and 3 molecules of fatty acid
how does condensation reaction occur to form triglycerides
ester bonds form between the glycerol and fatty acid chains
one water molecule released per triglyceride formed
three molecules of water released per triglyceride formed
what are phospholipids
a type of lipid that forms a bilayer (they are the main component of cell membranes)
what is the main difference between saturated and unsaturated fatty acids
the hydrocarbon tail
describe test for lipids
Emulsion test
-add ethanol to sample
-shake solution
-mixture will form white milky layer in presence of lipid
what do amino acids form
proteins/polypeptides
what are dipeptides
formed from condensation of two amino acids
what is the structure of amino acids
.each has a central (alpha) carbon atom
.central carbon atom has four atoms bonded to it
-NH2 (amine group)
-COOH (carboxyl group)
-H (hydrogen group)
-R (a side group)
5 aspects of basic amino acid structures
central (alpha) carbon
amine group
carboxyl group
hydrogen atom
R group
what does R group determine
how the amino acid interacts and bonds with other amino acids in a polypeptide
what is the only amino acid without a carbon atom in its R group
glycine
how many different amino acids are there
20
what two end terminals of two amino acids and joined during condensation reaction
amine terminal and carboxyl terminal
what are the four main functions of proteins
transport proteins
structural proteins
antibodies
enzymes
what is the role of channel proteins
transport molecules across the cell membrane that are too large to diffuse freely or molecules that carry a charge
role of structural proteins
.are long, strong polypeptide chains
.they are connected by cross-links that hold the chains parallel to each other
role of antibodies
(made up of polypeptide chains)
.are used in the immune response
.antibodies are diverse proteins each with a different sequence of amino acids
role of enzyme and brief structure
.biological catalysts
.increase the rate of a reaction without being used up
.they are tightly folded, complex proteins that are soluble
describe the test for proteins
Biuret test
.add sample to distilled water and biuret solution
.shake well
.test changes from blue to violet in presence of proteins
when will a biuret test be negative
if it only contains free amino acids as it tests for peptide bonds
what are 3 examples of proteins with quaternary structure
collagen
haemoglobin
insulin
when can quaternary structure take place
when there are multiple polypeptides
describe the lock and key model
enzyme and substrate fit together perfectly
the substrate is a key fitting into a lock
describe induced fit model
.enzyme and substrate come together and their interaction causes a small shift in the enzymes structure
.shift means enzyme and substrate can bind to form complex and catalyse reaction
what determines the shape of the enzyme active site and what else can change its shape
.the 3D tertiary structure
.environmental factors can change tertiary structure of the active site (and denature it)
how does PH affect enzyme controlled reactions
. Change PH changes number of OH and H ions surrounding the enzyme
.these interact with the charges on the enzyme’s amino acids
.resulting in a change in tertiary structure
how does increasing temperature effect enzyme controlled reactions
.increasing temperature will increase kinetic energy
.this increases chance of collision between enzyme and substrate, making them more likely in a set period of time
.increasing rate of reaction
.extreme temperature increase will change enzyme structure and denature it
explain increasing substrate concentration on rate of reaction 4 points
.increases the number of substrate molecules that can form enzyme-substrate complexes at any one time
.this increases initial rate of reaction
.but when all enzyme molecules are engaged in complexes rate cannot increase further
.rate will then plateau because enzyme is said to be saturated
what do competitive inhibitors do and what are they
.Competitive inhibitors have a similar shape to usual substrate and affect the active site directly
.the bind to the active site blocking access for the formation of ES complexes
.they are chemicals that slow down rate or stop reaction altogether
what is the function of non competitive inhibitors and structure 4 step explination
.are not shaped complementary to the active site
.they bind to the allosteric site of an enzyme
.changing the shape of the enzyme/active site
.causing it to no longer be complementary to the substrate molecules
two ways to calculate rate of reaction
-decrease in reactants/time
-increase in products/time
three main uses of water
reactant in cells (photosynthesis, hydrolysis)
provides structural support in cells
keeps organisms cool to maintain optimum body temperature
how is water polar
oxygen atoms are slightly negatively charged
hydrogen atoms are slightly positively charged
what are the five useful properties of water
.cohesive
.good solvent
.good metabolite
.high heat of vaporisation
.high heat capacity
why does water have cohesive properties and why is that useful
. cohesion is the strong attraction between water molecules due to hydrogen bonds
.cohesion produces surface tension
why is water a good solvent
.water is a polar molecule (positive end attracts negative ions negative end attracts positive ions )
..ions and polar molecules can easily dissolve in it
what does water being a good metabolite mean
.is used or formed in many metabolic reactions such as condensation or hydrolysis
what is waters high heat capacity caused by
hydrogen bonding between water molecules
what are the three components of ATP
adenine
ribose
3 phosphate groups
what simply is the function of ATP
used to power most energy-requiring cellular reactions
what is formed when ATP is hydrolysed
ADP
what does ADP stand for
adenosine diphosphate
what enzyme catalyses ATP hydrolysis
ATP hydrolase
what does DNA stand for
deoxyribonucleic acid
What isomer of glucose is cellulose made of
Beta glucose
what does RNA stand for
ribonucleic acid
what are the two polymers made from the monomer nucleotide
DNA
RNA
what are the three components of a nucleotide
phosphate group
pentose sugar
nitrogenous base
what are the four bases in DNA
thymine
guanine
cytosine
adenine
what is the sugar in DNA called
deoxyribose sugar
what is the sugar in RNA called
ribose
what are the four bases in RNA
adenine
guanine
cytosine
uracil
how do nucleotides join to form polynucleotides
nucleotides join via condensation reactions between the phosphate group of one nucleotide and the sugar of another forming a phosphodiester bond
how many hydrogen bonds form between adenine and thymine
2
how many hydrogen bonds form between cytosine and guanine
3
what word is used to describe the positioning of the polynucleotide strands in the double helix when they run in opposite directions
antiparallel
what two nitrogenous bases are purine
adenine and guanine
what two (technically 3) nitrogenous bases are pyrimidines
thymine
uracil
cytosine
