1.3 Proteins Flashcards
How do amino acids join?
they join together by a reaction between the amino group of one amino acid And the carboxyl group of another
They join in a condensation reaction and a molecule of water is lost
What is dipeptide
is two amino acids joined by a peptide bond
What is a peptide bond
The bond formed by a condensation reactions between amino acids
`What is a polypeptide bond
is a long chain of amino acids joined by peptide bonds
How is a protein formed
Proteins are formed in a condensation reaction when amino acid molecules join together and a water molecule is removed. The new bond formed in protein molecules where amino acids have joined
What is a disulfide bond
is a strong covalent bond formed as a result of an oxidation reaction between sulfur groups in cystine or methonince molecules which are close together in the strcuture of polypeptide
How do hydrogen bonds break
when the pH or temperature conditions change
How are hydrogen bonds formed
In amino acids, tiny negative charges are present on the oxygen and the carboyxl group
And
Tiny positive charges on the hydrogen atoms of the amino groups
When these charged groups are close together they attract
And a hydrogen bond is formed
Why are hydrogen bonds important
they are important in the folding and coiling of the polypeptide chains
Where can collagen molecules be found
fibrils
Where are collagen fibres found
They are found combined with the bone tissue, giving it tensile strength
Which strucutre(s) does globular proteins have
Complex tertiary and sometimes quaternary strucutre
What does globular proteins fold into
They fold into spherical (globular) shapes
Why do globular proteins molecules behave diffrently in water
Because their carboxyl and amino acids ends give them ionic properties
Instead of dissolving in water what do globular proteins form
Colloids
Why are globular proteins important
globular proteins form some enzymes and some hormones and involved in maintaining the structure of the cytoplasm
What is the strucurre of hameoglboin
Made up pf 574 amino acids
Arranged in four polypeptide chains which are held together by disulfde bonds
What ar econjugated proteins
protein that functions in interaction with other chemical groups attached by covalent bonding or weak interactions
What is a prosthtic group
Is the molecule that is incorporated in a conjugated protein
What is a glycoprotein
Is a protein with a carbohydrate prosthtihic group
Why are glycoproteins important
Glycoproteins acts a lubricant they are slippery and viscous and reduces friction
What are lipoproteins
are proteins conjugated with lipids and are very important in the transport of cholestrol
What is a primary struture
The linear sequnce of amino acids joined by peptide bonds`
What is a secondary structure
The repeating pattern in the strucutre of the peptide chains such as A- helix or B- pleated sheets
What is the tertiary strucutre
The three dimensional folding of the secondary structure
What is the quaternary strutcure
the three dimensional arrangement of more that one tertiary polypeptide
Why are disulfide bonds imporant
they are important for holding folded polypeptide chains in place
What are salt bridges
ionic bonds can form between some of the strongly postive and negative amino acid side chains found buried deep in the protein molecules
What is a fibrous protein
Are proteins that have long parallel polypeptide chains with occasional cross- linkages that form into fibres nit with little tertiary structure
How many polypeptide chains is collagen made up of
3
what type of structure of is collagen
Primary strucuture of these chains is repeating sequences of glycine with 2 other amino acids
the 3 alpha chains in collagen
arragned in a unique triple helix held together by large number of hydrogen bond
Strcuture of collagen
Primary strucutre with repeating sequences of glycine
the 3 alpha chains arrange into a triple helix held together by loads of hydrogen bond
how is a peptide bond is formed
a bond forms between the carboxyl group of one amino acid and the amino group of a second amino acid
one water molecule is released
What are the two common secondary structures of proteins?
Beta-pleated sheet
Alpha-helix
What bonds are present in teriarty strucutre
Ionic bonds, hydrogen bonds , and displhuide bridges
what are functions for globular proteins
Enzymes
Messengers
What type of structure is found in globular proteins
Tertiary
what is a conjugated protein?
specific type of globualr protein that contains a prosthetic group
What are some similarities between hemoglobin and collagen
Both are polypeptides formed from amino acid monomers
Both have peptide bonds formed in condensation reactions
What are differences between hb and collagen
Hemoglobin has a prosthetic hame group that contains iron to bond with oxygen, collagen has no prothesthic group.
hb is 4 pp chains collagen is 3 chains
hb is soluble, collagen is insoluble
what do proteins contain
Hydrogen and oxygen they all contain nitrogen and many proteins also contain sulfur
Why is the R group important
the structure of R group affects the way the AA bonds with other in the proteins
This depends if the r GROUP IS polar or not
how do AA join
join together by a reaction between the amino group of one AA and the carboxyl group of another
How is a protein formed q
when the polypeptide folds or coils or associates with other polypeptide chains
Where does the peptide bond is formed
Between the OH of the carboxyl and the H of the amino group
LABEL all fibrous protein properties
Insolubale
Hormones
Hydrophobic on the outside
Repeating AA sequnces
LABEL or globualr protein properties
Soluable
Enzymes
Hydrophobic on the outside
-Little reption of AA sequences
How des a change of AA lead to change in the structure and properties of a protein
Change in primary sequence
which leads to changed h bonds which affects the folding of the secondary strucutre
describe dispuhlpoide bridges in hte tertiary strucuture of protiens
strong covlaent bonds between molecules of the AA cytecine
