2.2 Proteins Flashcards
(27 cards)
what is a protein
large polymer comprised with long chain of amino acids
what are 3 roles of proteins
1 they form structural components of animals e.g muscle, tendons, bones
2 they adapt specific shapes as enzymes
3 membranes have proteins constituents that’s act as corner + pores for active transport across membranes + facilitated diffusion
what elements does it contain
Each amino acid contains C,H,N,O and S sometimes
what is the structure of an amino acid
- All protein chains of amino acid contain amine group (NH3) at one and + carboxyl group (-COOH) at the other
-The R group can vary by size polarity and charge
what is a peptide bond
A covalent bond formed when two amino acids are joined together in a condensation reaction
what does protease enzyme do
Protease enzymes break down protein peptides bond in digestion
what is a dipeptide
When two amino acids join they are a dipeptide
what is a polypeptide
Polypeptide is when many amino acids join together
what is the primary structure
It is the sequence of amino acid in the polypeptide chain.
why is primary structure important
The function of protein depends on the structure, which depends on the amino acid order.
what is the secondary structure
The coiling or folding of the amino acid chains to form either an a-helix or B pleated sheet. This is due to H bonds. (Between C equals O And H in the amine a group) to hold the structure.
what is the tertiary structure
Further folding of a secondary structure which forms 3D unique shape and is held by; Iconic, Hydrogen, disulphide Bonds.
The iconic + sulphide Form between R groups of different amino acids.
disulphide bonds only sometimes occur as there must be sulphur in R- group.
what is the quaternary structure
Where proteins consist of more than one polypeptide chain bonded together.
what is hydrogen bond in the tertiary structure
Form between C = O in carboxyl groups and H in an amine group.
what is the ionic bond between tertiary structure
Form between carboxyl + amine groups that are part of R groups
what are the hydrophobic and hydrophilic interactions in the tertiary structure
R groups are hydrophobic + tend to stay in the middle of polypeptide to stay away from H2O.
The hydrophilic parts are found at edge to be close to water.
Hydrophobic + Hydrophilic interactions cause twisting of amino acids which charge shape of the protein.
These interactions can be especially Important influence given that most protein are tube found surrounded by H2O inside a living Organism.
what are disulphide bonds
Bond formed Between 2 sulphurs in R group and forms a bridge.
These are strong covalent bonds.
Made from Cysteine amino acid (They contain s)
What are fibrous proteins
They are long thin protein that is insoluble in water.
They are made from repeating sequences of amino acids and are metabolically inactive leading them to have structural roles in an organism
3 types of fibrous proteins and their uses & structure
Collagen
Keratin
Elastin
Collagen
Found in the artery wall and a layer of collagen prevents the artery from bursting when withstanding HP
Tendons are made from collagen and connect muscle to bones allowing them to pull bones
Cartilages + Connective tissue are made from collagen
Bones are made from collagen + then reinforced with calcium phosphate which makes them hard
Keratin
Is found in body parts that need to be hard to provide mechanical protection as well as acting as an impermeable barrier to infection being waterproof and preventing entry of Waterbourne pollutants
Keratin can be found in nails, claws, hooves, horns, and scales
They are rich in cystine which means they have many disulphide bridges in its polypeptide as well as having many H-bonds to provide additional strength
Elastin
Due to coiling and cross linking of the elastin molecules its long and extensible (stretchy)
Skin can stretch around bones and muscles due to elastin
Elastin in lungs allow them to deflate and inflate
They are also found in the bladder to help it expand to store urine
Elastin also helps our blood vessels widen and stretch + recoil as blood is pumped through them helping maintain the pressure wave of blood as it passes through
Globular Proteins
Type of 3d protein that is spherical and soluble in water and having metabolic roles
They have Hydrophobic R groups on the inside the hydrophilic R groups on the outside
3 types of Globular proteins , their roles and structure
Haemoglobin
Insulin
Catalase