Module 2: Foundations In Biology - Biological Molecules Flashcards
In a protein, what are the 4 main elements??
Carbon
Hydrogen
Oxygen
Nitrogen
How many different types of amino acids are there??
20
What is the smallest amino acid??
Glycine
What is the R group of Glycine??
Hydrogen
What is the R group of Cysteine
CH2-SH
What does an R group determine??
Determines properties and bonds that the amino acids form
Hydrophobic
Water repellent
Hydrophyllic
Water loving
Peptide bonding
Two amino acids joined in a condensation reaction
The bond between them is a peptide bond
What is a peptide bond formed between??
Amino acids
What is the resulting compound of peptide bonding??
A dipeptide
In peptide bonding when do the amino acids join??
Amino acids join when the amine and carboxylic acid groups connected to the central carbon atom react
What happens to the hydroxyl in the carboxylic acid group during peptide bonding??
The hydroxyl in the carboxylic acid group of one amino acid reacts with a hydrogen in the amine group of another amino acid
When is a polypeptide formed??
When many amino acids are joined together by peptide bonds
When a polypeptide is formed what is the reaction catalysed by??
Catalysed by the enzyme peptidyl transferase
Where can the enzyme peptidyl transferase be found??
In ribosomes
What is the structure of proteins??
Proteins consist of one or more polypeptides arranged as complex macromolecules
All proteins contain the elements carbon, hydrogen, oxygen and nitrogen
What do many bonds lead to (structure of proteins))
Different types of bonds are formed and these bonds lead to the formation of long chain amino acids
These long chain amino acids fold into complex structures
What is the effect of having different sequences of amino acids??
Leads to different structures with different shapes being produced
Why are shape specific proteins important??
Because the specific shapes of proteins are vital for the many functions proteins have within organisms
Primary protein structure
A sequence chain of amino acids
Which bonds are present in the primary protein structure??
Peptide bonds
Secondary protein structure
Hydrogen bonding of the peptide backbone causes the amino acids to fold into a repeating pattern
Which bonds are present in the secondary protein structure??
Hydrogen bonds
Tertiary protein structure
Three dimensional folding pattern of a protein due to side chain interactions
What bonds are present in the tertiary protein structure??
Hydrogen bonds
Ionic bonds
Disulfide bonds
In cysteine what are disulfide bonds formed between??
Formed between two sulphurs
Quaternary protein structure
Protein consisting of more than one amino acid chain
Which bonds formed in the quaternary protein structure??
Hydrogen bonds
Ionic bonds
Disulfide bonds
Hydrophobic/hydrophilic interactions
If the order of amino acids change what happens to the primary structure of the protein??
Primary structure changes
Gives a different function
Where will the bonds be to maintain the quaternary structure??
Between polypeptide chains
Hydrophilic interactions in the middle of the structure
Ionic bonds
Form between positively and negatively charged groups
How can ionic bonds be broken??
By high temperature or a change in ph
What are Disulphide bridges/bonds formed between??
Form between two cysteine amino acids
Disulphide bonds/bridges
Involves sharing electrons so is a covalent bond
Properties of a Disulphide bridge/bond
Strong bond, not broken by an increase in temperature or change in pH
Why do hydrophobic amino acids repel water??
They have non polar R groups
Which way will hydrophobic amino acids face??
Face into cytoplasm or tissue fluid
So will face inwards
Interact and cluster
Why do hydrophilic amino acids love water??
Because they have polar R groups
Which way will hydrophilic amino acids face??
Will face outwards into the tissue fluid or cytoplasm
What do hydrogen bonds form between??
Form between an electropositive H+ atom and an electronegative O- atom
How can hydrogen bonds be broken??
Can be broken by a high temperature or change in pH
Structure of a globular protein
Protein curls into a ball
Hydrophobic R face in
Hydrophilic R face out
Soluble
Structure of a fibrous protein
Proteins form long strands
Insoluble
Very tough
Catalytic example of a globular protein
Enzymes such as amylase and lipase
Regulatory example of a globular protein
Hormones such as insulin
Transport example of a globular protein
Haemoglobin
Protective example of a globular protein
Antibodies
Structural example of a fibrous protein
Collagen
Structural example of a contractile protein
Actin, myosin
What is a prosthetic group??
A prosthetic group is a non-protein part which is permanently bound to the protein and is essential for its purpose
Structure of haemoglobin (globular protein)
2 identical chains called alpha chains
2 identical but different chains called beta chains
Chains packed closely together
Problems with haemoglobin - sickle cell anaemia
Single point mutation recessive disease
In a beta chain, causes amino acid substitution polar for valine
6th amino acid in chain
What are simple proteins
Simple proteins only contain amino acids in their structure
What are conjugated proteins
Conjugated proteins contain amino acids plus some other type of chemical molecule
Structural proteins: collagen
Found as strong non-elastic white fibres in tendons, cartilage and bone
Structural proteins - elastin
Found as yellow elastic fibres in ligaments and joint capsules
Structural proteins - keratin
Found as an impermeable protein in skin, hair, feathers, nails and hooves
What type of protein is haemoglobin
Globular
What type of protein is catalase
Globular
What type of protein is insulin
Globular
What type of protein is collagen
Fibrous
What type of protein is keratin
Fibrous
What type of protein is elastin
Fibrous
What is the shape of haemoglobin
Ball shape
What is the shape of catalase
Ball shape
What is the shape of insulin
Ball shape
What is the shape of the collagen
Strand shape
What is the shape of keratin
Strand shape
What is the shape of elastin
Strand shape
Number of polypeptide chains in haemoglobin
4
Number of polypeptide chains in catalase
4
Number of polypeptide chains in insulin
2
Number of polypeptide chains in collagen
3
Number of polypeptide chains in keratin
4
Number of polypeptide chains in elastin
Many
Is haemoglobin soluble or insoluble
Soluble
Is catalase soluble or insoluble
Soluble
Is insulin soluble or insoluble
Soluble
Is collagen soluble or insoluble??
Insoluble
Is keratin soluble or insoluble
Insoluble
Is elastin soluble or insoluble
Insoluble
Amino acid structure in haemoglobin
2 alpha chains
2 beta chains
Amino acid structure in collagen
Glycine every 3rd amino acid
Glycine’s r group is hydrogen only
Allows light coiling of polypeptide chains
Amino acid structure of keratin
Fibrous
High proportion of cistane and Disulphide bonds
Amino acid structure of elastin
Cross links are covalent bonds between elastic fibres
Prosthetic group of haemoglobin
Haem - iron
Prosthetic group of catalase
Haem - iron
Prosthetic group of elastin
Many lysine can form covalent bonds
Prosthetic group of insulin
Doesn’t have one
Prosthetic group of collagen
Doesn’t have one
Prosthetic group of keratin
Doesn’t have one
Role of haemoglobin
Oxygen and carbon dioxide transport
Role of catalase
High conc found in liver
Involved in breaking down h2o2 into water and oxygen
Role of insulin
Insulin lowers blood glucose concentration by converting glucose into glycogen
Role of collagen
Present in ligaments and tendons, skin, the outer layer of blood vessels
Staggered ends to prevent weak points
Role of keratin
Found in hair and nails
Role of elastin
Elastic fibres in arteries, veins, arterioles, bronchioles and airways
Can stretch and relax
Similarities between haemoglobin and catalase
Have a haem prosthetic group
Have a 4o structure
Are soluble
Are globular
4 polypeptide chains
Ball shaped proteins
Which elements do carbohydrates contain??
Carbon
Hydrogen
Oxygen
3 types of carbohydrates
Monosaccharide
Disaccharide
Polysaccharide
Examples of monosaccharides
Glucose
Fructose
Deoxyribose
Examples of disaccharides
Sucrose
Lactose
Maltose
Examples of polysaccharides
Starch
Glycogen
Cellulose
Alpha glucose structure
Hydrogen above the ring on C1
Beta glucose structure
H below the ring on C1
Colorimeter
Can record absorbable or transmission
Will a paler colour solution absorb more or less light
Absorb less light
Therefore more light is transmitted
Will a darker coloured solution absorb more or less light
Absorb more light
Therefore less light is transmitted
Where do you naturally find fructose
In fruit
What is the structural difference between ribose and deoxyribose
There is an extra oxygen molecule in ribose
What molecule is ribose found in?
RNA
What molecule is deoxyribose found in??
DNA
What type of bond joins 2 monosaccharides and what type of reaction is this??
Glycosidic bonds, condensation reaction
What is the effect of a glycosidic bond??
Creates a straight chain shape
What is a molecule of water made up of
2 hydrogen atoms, 1 oxygen atom which are joined by a covalent bond
Why is water a polar molecule
Electrons are not evenly shared in the covalent bond
More of the electrons are pulled closer to the oxygen molecule giving it a relative delta negative charge and the hydrogens are delta positive
What bonds are present in water molecules
Hydrogen bonds and covalent bonds
Are hydrogen bonds weak or strong in water??
The bonds are weak
In the liquid form water molecules move around and break and reform hydrogen bonds
Thermal stability of water - what happens with lower temperatures of water
With lower temperatures water molecules have less kinetic energy so more hydrogen bonds form and are less likely to break
What happens when water freezes??
On freezing, hydrogen bonds between water molecules form a lattice like structure
This makes the water molecules more spread out
Why does ice float
Because the spread out water molecules are less dense than water in its liquid form
What are the advantages of water freezing to living organisms??
Insulated the water below
Organisms below the ice survive by being able to move around and obtain food and oxygen
Water currents still occur which moves nutrients
The ice also provides a surface for organisms to live on
What is the effect of increasing water temperatures on water molecules??
Water molecules have more kinetic energy and move around more
What is required for evaporation to occur??
Hydrogen bonds between molecules must be broken which requires a lot of energy
What is high specific heat capacity
Energy needed to raise the temperature of one gram of substance by one degree Celsius
What is latent heat of evaporation
Amount of energy needed to break the hydrogen bonds between water molecules
Evaporation of water from the skin is an example of what??
Latent heat of evaporation
When does cohesion occur??
The hydrogen bonds between the molecules pulls the water together
What is the effect of surface tension??
Allows organisms to walk on water eg pond skaters and flies
Why is it important for water to be transparent
Allows light to penetrate through a body of water
Facilitates photosynthesis of aquatic plants and allows predators to spot prey beneath the water above and for prey to see their predator
