Biological Molecuoles 1 Flashcards
What are monomers?
smaller units from which larger molecules are made
What are polymers?
molecules made from a large number of monomers joined together
What is a condensation reaction?
a reaction that joins two molecules together to form a chemical bond whilst eliminating of a molecule of water
What is a hydrolysis reaction?
A reaction that breaks a chemical bond between two molecules and involves the use of a water molecule
What is a monosaccharide
Monomers from which larger carbohydrates are made
How is a glycosidic bond formed?
A condensation reaction between two monosaccharides
Name the three main examples of polysaccharides.
glycogen, starch, cellulose
Describe Benedict’s test for reducing sugars
gently heat a solution of a food sample with an equal volume of Benedict’s solution for five minutes, the solution turns orange/brown if reducing sugar is present
Name the two main groups of lipids
Phospholipids and triglycerides (fats and oils)
Give four roles of lipids
source of energy, waterproofing, insulation, protection
What is an ester bond?
A bond formed by a condensation reaction between glycerol and a fatty acid
Describe the emulsion test for lipids
mix the sample with ethanol in a clean test tube, shake the sample, add water, shake the sample again, a cloudy white colour indicates that lipid is present
What are the monomers that make up proteins?
Amino Acids
Draw the structure of an amino acid
R
|
H2N — C — COOH
|
HHow is a peptide bond formed?
a condensation reaction between two amino acids
What is a polypeptide?
many amino acids joined together
Describe the biuret test for proteins
mix the sample with sodium hydroxide solution at room temperature, add very dilute copper(II) sulfate solution, mix gently, a purple colour indicates that peptide bonds are present
How does an enzyme affect a reaction?
It lowers the activation energy
Give five factors which can affect enzyme action.
temperature, pH, enzyme concentration, substrate concentration, inhibitor concentration
What is a competitive inhibitor?
A molecule with a similar shape to the substrate, allowing it to occupy the active site of the enzyme
What is a non - competitive inhibitor?
A molecule that changes the shape of the enzyme by binding somewhere other than the active site.
Water is a polar covalently bonded molecule. Explain.
Because the electrons are not shared equally there is an uneven distribution of charge in which the opposite to the bonded parts of hydrogen are slightly positive and the top of oxygen is slightly negative.
Cohesion in water molecules
Weak Inter-molecular forces between the slightly positive H and the slightly negative oxygen due to its polarity are called hydrogen bonds. Together many mean there is some strength in the hydrogen bonds.
Cohesion of water shows in various forms
What causes h20 to travel up the xylem
Cohesion results in droplets curving inwards (tear drop shape)
Results in súrcate tensión
Adhesion in water molecule
The attraction between H2O molecule and the wall of container or even xylem wall
Causes a Meniscus shape in container
Explain what like dissolves like means
Water is a solvent - a polar solution dissolves other polar or ionic solids like salt
What is a metabolite and give an example
Involved in metabolic reactions
Can be a substrate or a product hence is used as a transport medium
For example condensation and hydrolysis
In animals and humans how is water used as a transport medium.
Human and Animals plasma
Plants is water and xylem
What is specific heat capacity?
The energy needed to raise the temperature of 1kg by 1°C
Why is water a buffer
A large amount of energy is needed to raise the temperature hence the water resists changes.
What is thermostable environment
An environment that doesn’t change much in terms of heat - for example water; the sea doesn’t change much in terms of temp so animals can live there
What is high latent heat of vaporisation and how does it relate to human body
A lot of energy is needed to break all the Hydrogen bonds and molecules with enough energy evaporate carrying heat away, hence when we sweat we cool down because a lot of energy evapourated
Why does ice float on water
As water freezes it expands and the molecules are held further apart so when frozen is less dense than liquid water so floats. Hence the ice insulates the water below so it does at freeze.
Biological Macromolecules
Contain carbon
Can be organic (C-H bonds)
Can be inorganic (CO2)
Saturated macromolecules have
No double carbon covalent bonds
Unsaturated macromolecules have
double carbon bonds
Polymers go through hydrolysis to…
Monomers
Monomers go through condensation reaction to form
Polymers
An example of a monomer is amino acids give the name of the polymer it forms and the cellular structure it is found in
Polypeptide chain
Intermediate Filament
An example of a monomer is nucleotide give the name of the polymer it forms and the cellular structure it is found in
DNA Strand
Chromosome
An example of a monomer is monosaccharide give the name of the polymer it forms and example and the cellular structure it is found in
Polysaccharide
Starch
Starch grains in chloroplast
An example of a monomer is fatty acids give the name of the polymer it forms and the cellular structure it is found in
Fat molecule
Adipose cells with fat droplets
What are carbohydrates made of and give which types are simple and which are complex
Carbon, hydrogen and oxygen
Monosaccharides and Disacchardies are simple
Polysaccharides are complex
General formula of monosaccharides
(CH2O)n
Where n is the number of carbon atoms
Two shape forms of glucose diagrams are called
Linear (acyclic form)
Cyclic Form
Must know
Glucose formula is
C6H12O12
Two isomers of glucose are and name difference at one point
Alpha glucose and beta glucose
There are two ring forms and one linear
Beta is the same as alpha however at carbon one the OH is on top and the H is in the bottoms
Must know these diagrams
Disaccharides are
What type of bind
What type of reaction
Two monosaccharide units join forming a glycosidic bond
They can be made by two of the same of two different monosaccharides
It is a condensation reaction so a molecule of water is expelled
Maltose is made from which monomers and give word equation and what type of saacharide
Glucose + glucose-> maltose + water
Disaccharide
Sucrose is made from which monomers and give word equation and what type of saacharide
Glucose + fructose -> sucrose + water
Disaacharide
Lactose is formed from which monomers and give word equation and what type of saacharide
Glucose + glacatose -> lactose + water
Disaacharide
OILRIG
oxidation is loss reduction is gain
Ionic equation for copper sulfato Benedicta reagent
Cu2+ + e- -> Cu+
Non reducing sugars test
Once they show a negative result against Benedicta solution
Boil unknown solution with dilute HCl,which causes any disaccharide molecules that might be present to hydrolyse (split) into monosaccharides which are all reducing sugars
Then repeat Benedicts test
All monosaccharides are
Reducing sugars
Hydrolysis is the
Addition of H2O that causes break down
Starch test
Changes colour of iodine from yellow to blue-black
2cm3 if sample into test tube or spotting tile
Blue-black indicates the presence of starch
Polysaccharides are
Polymers firmed by the joining of many monosaccharides by glycosidic bonds (formed through many condensation reactions)
When they are hydrolysed they are broken into monosaccharides or disaccharides.
Polysaccharides generally perform two functions which are….
Storage of energy and structural help
Polysaccharides storage of energy in plants
Starch is only made in plants which is a major energy source for humans
Starch is made up of two polysaccharides; Amylose (20%) and Amylopectin (80%)
Both are chains of alpha glucose
Amylase acts on starch
It is found in salivary glands and breaks down into maltose
Amylose (20%)
Formed by an alpha glucose chain
Alpha 1,4 glycosidic bonds between monomers ((the one after O)C1 and C4 join in a condensation reaction)
Chain forms into a slightly coiled shape
Amylopectin (80%)
Formed by an alpha glucose chain
Alpha 1,4 and alpha 1,6 glycosidic bonds (carbone one to carbon four and carbon one and carbon six)
Branched shape due to extra alpha in 1,6 bonding
Forms branches slightly coiled chain
Polysaccharides storage of energy in animals
Glycogen is found as a means of storage in animal, fungi and bacterial cells
A more branched version of amylopectin
Formed from chains of the monosaccharide alpha glucose but there is less alpha 1,4 and more alpha 1,6 hence more branching and more area for enzymes to work on hence quicker mobilisation of energy
Stored in small granules and found mainly in the muscles and liver
Why is it useful that glycogen has more alpha 1,6 bonds then alpha 1,4
There is more branching hence more end and surface area for the enzymes to walk on hence more energy is mobilised in less time
Why do plants store energy in the form of starch as opposed to glycogen
There is no need for quick mobilisation of energy
Why are glycogen and starch good for storage
Compact - a lot can be stored in very little space
Easy access to glucose- energy source released by the hydrolysis of glucose molecules from multiple branched ends
Large and insoluble - doesn’t diffuse out of cells or affect water potential
Polysaccharide Structural support
Cellulose
Major component of plant cell walls
Formed by chains of beta glucose
Small change of OH pointing up at C1 causes huge differences in the structure and function
Every other glucose molecule is rotated by 180° or flipped to allow the glysocisdic bonfd to form between beta glucose molecules
Straight unbranched chains are formed and because of the flipping the C2H2OH is in the bottom weak hydrogen bonds are built between chains and it stabilises the structure
Cellulose strands are arranged to make tough microfibrils providing strength and support
Structural roles of cellulose
Provides rigidity
Prevent plant cells bursting when water enters via osmosis
Maintains turgidity in plant cells and therefore in the whole plant (stems and leaves) maximising the surface area for photosynthesis
Lipids -> difference in oil and fat
A liquid form is oil
A solid form is fat
Characteristics of lipids are
They are all made of carbon and hydrogen and a small amount of oxygen
They are non-polar due to a large percentage of carbon and hydrogens hence add insoluble in water (hydrophobic)
Soluble in other solvents that are organic for example ethanol and acetone
Explain how a change in the primary structure of a protein mag result in a different three dimensional structure
A change in the sequence of amino acids means the tertiary structure may fold differently forming bonds in different places
Hydroxylating means
Adding OH group
Two proteins have the same number and type of amino acids but a different tertiary structure
Explain why
A different sequence of amino acids forms ionic,disuadidos and hydrogen bonds in different places hence folds differently
Explain how cellulose molecules are adapted for their function in plant cells
Linear chains become linked by H+ bonds to form fibrils that provide strength to cell for example don’t burst when water enters via osmosis
Explain one way in which starch molecules are adapted for their function in plant cells
Compact - more energy less space
Insoluble hence don’t affect water potential
Triglycerides store energy in what type of cells
Adipose
Phospholipids are the main components in
Cell membranes
Glycerol formula and monomer for which polymer/s
C3H8O3
(3 OHs)
Triglycerides and phospholipids
Properties of saturated fatty acids
Contain only single covalent bonds between carbon atoms Form linear chains Fatty acids pack closely together Strong attraction between chains Solid at room temperature
Properties of unsaturated fats
Contain one or more double covalent bonds between carbon atoms, which causes the chains to bend
The non linear chains do not allow fatty acid molecules to pack closely together
Fewer interactions between fatty acid chains hence weaker attraction
Liquids at room temperature
The more double Covalent bonds between carbon atoms the lower the melting point
Ester bonds are
C double bond O and one bond H
Triglycerides are located where and for what reason/s
Around delicate organs like heart or kidney for protection
And under skin to insulate the body
Triglycerides structure description
Each fatty acid forms an Ester bond with glycerol in a condensation reaction which involves the removal of 3 water molecules (one for each Ester bond)
Hydrolysis of a triglyceride results in
Splitting the triglyceride back into glycerol and 3 fatty acids.
Hydrolysis of a triglyceride requires an addition of
3 water molecules
Lipid Emulsion Test
Mix sample of fat with (5cm3 of alcohol) and shake tube
Add five cm 3 of cold water and shake until a milky white colour indicated the presence of a lipid
For control repeat procedure with a sample of water and now white should be seen
Describe diagram of phospholipids
The head of the molecule is a negatively charged phosphate which is hydrophilic (attracts water) and has two tails which are long chains of fatty acids that are hydrophobic hydrocarbons. They can be either saturated or unsaturated not necessarily the same tail.this means the head is polar
Hydrophilic meaning
Attracted to water
Why do we say phospholipids are ampipathic
Has both hydrophobic and hydrophilic parts
Describe the diagram of a membrane
Two rows of polar heads with tails facing each other. The hydrophilic phosphate head interacts with aqueous solution on either side that could be for example cytoplasm or muscle tissue whilst the negative hydrophobic hydrocarbon tails face each other.
Vesicles have hydrophobic or hydrophilic heads
Hydrophilic
Roles of Lipids
Waterproof - skin,waxy cuticle of leaf
Thermal Insulation - slow conductors of heat
Protection - of organs
Buoyancy - slightly pensé dense than H2O
Electrical Insulation - around nerves to increase electrical impulse speed
Hormones - steroid hormones are derived from cholesterol like cortisol,oestrogen and progesterone
H+ ions in body contribute to
pH of bodily fluids
Nitrogen is needed for the body because
It is a source of amino acids and helps to further synthesise human proteins. RNA needs nitrogen as does the digestive process.
Carbon makes up 18% of the body - what’s its function?
Sugars in body hold C atoms. Macromolecules including proteins, RNA & DNA, lipids and other carbohydrates. A subset of any organic molecule
Oxygen needed for body?
Oxidation changes food and liquid into energy - ultimately provides fuel for our body.
Phosphorus is needed in the body to
Build and repair bones and teeth, help nerves function, muscles contract. 85% is in bones the rest is stored in tissues in the body
Silicon is needed in the body to
Make proteins, regulate gene expression and for the building and repairing of DNA and to metabolise food.
Sodium is needed in the body to
Maintain a balance of water in and around cells - important for proper muscle function and never even function and to maintain a stable blood pressure
Magnesium is needed in the body because
It is used in over 300 biochemical reactions and for the active transport of Ca and K ions across cell membranes
Iron is needed in the body to
Carry oxygen in haemoglivin if RBC so energy can be produced
Low iron means low ATP which is what energy turns into hence fatigue
Calcium is needed in the body to
Build string bones and teeth
Clotting blood
Receiving and sending nerve signals
Relaxing muscles
Structure of triglycerides related to their properties
High ratio of energy storing of carbon hydrogen bonds to carbon atoms so make an excellent source of energy
Low mass to energy ratio which means a lot of energy in a small volume. This means it easier for animals to move around so reduces mass
Large non polar insoluble in water hence there is no water potentials
High ratio of hydrogen to oxygen so release water when oxidised so important source for organism living in dry deserts
Monomer for proteins are
Amino acids
Structure of amino acid
Amino group - NH2
Carboxyl Group - COOH
hydrogen atom connected to the carbon in middle
R group under main carbon which makes each amino acid different
Peptide bonds are formed between what atoms, are what type of reaction and what element within those atoms
Amino acids
Condensation so expel water molecule
Nitrogen combines with the carbon
Lose one H from nitrogen and carboxyl group lose OH
Primary structure of polypeptide
Linear sequence of amino acids that form one polypeptide chain
Peptide bonds
Secondary Structure of proteins
Secondary structure Creates three dimensional geometry with regular folding patterns forming a tightly coiled alpha helix structure or beta sheet which is like a zig zag n shape
Hydrogen bonds in seciondary structure
Tertiary structure polypeptide
The overall shape of protein so either globular or fibrous
Disulphides bridges between between two sulfur atoms but only in a structure with sulfur with hydrogen at end so not in methanine
Contains secondary structure forms
Hydrogen bonds stabilise
Ionic bond between amino group and carboxyl group
Three types of bonds that stabilise tertiary structure in order of highest strength to lowest
Disulphides bridge
Ionic are easily broken by changes in pH
Hydrogen bonds numerous so strong but easily broken
Quaternary structure polypeptide
Describes appearance when a protein is composed of two or more polypeptide chains which may hyyderogen bonds with each other in unique patterns to create the desired protein the desired protein configuration
Biuret test
Place a sample of in test tube
Add sodium hydroxide and copper sulfur (birrete Reagan’s) and mix
Must be equal parts
Blue to purple indicates presence of proteins
The quaternary structure of collagen makes it a suitable molecule for tendon
Individual polypeptide chains are held together in fibres are held together by bonds between amino acids in adjacent chains
Structure description of fibrous proteins
Primary is unbranched polypeptide chain
Secondary is tightly wound
Loads of the amino acids glycine helps close packing
Tertiary chain is twisted into a second helix
Quaternary made up of three such polypeptide chains wound together like a rope
Difference in function between globular and fibrous proteins
Metabolic functions
Structural function
Explain that all living things have a similar biochemical basis
Variety of organisms based on versatile carbon atom. Only few atoms that can bind to carbon in living organisms ergo life is based on a few elements.
Triglycerides and phospholipids structural difference is
One fatty acid is substituted by a phosphate molecule
Phospholipid structure related to their properties
Polar and have hydrophilic phosphate head and hydrophobic tail so form a hydrophobic belayer that acts as a barrier between inside and outside of cell
Hydrophilic allows holding of cell surface membrane
Structure allows doming of glycolipids which are important in cell recognition
Proteins variety of functions
Channel and carrier proteins for transport
Enzymes for synthesis of atp and other proteins
Ribosomes
Importance of water
Metabolism - hydrolysis and condensation eg: amino acids and proteins.
Solvent - readily dissolved gases like O2 and CO2 so acts as a transport medium. Provides aqueous medium for enzyme reactions to take place.
High latent heat if vapoursiation means that sweating cooks down mammals as a lot of heat energy in the sweat.
Cohesion and adhesion allows for transpiration
High specific heat capacity - thermos table buffer for aquatic organisms
Hard to compress - hydrostatic skeletons
Inorganic ions hydrogen, iron and phosphate
Phosphate ions make compounds more reactive by lowering Ea : glycolysis
Hydrogen ions determine pH so affect enzyme reactions
Fe in haemoglobin allows max four oxygen to bind for transport
