Module 2 Section 2 - Proteins Flashcards
What are proteins
Polymers
What are amino acids
Monomers
A dipeptide is …..
Formed when TWO amino acids join together
A Polypeptide is…..
Formed when MORE THAN TWO amino acids are joined together
All amino acids have….
The same general structure. A carboxyl group and amino group
What is the difference between amino acids
The variable group they contain
What elements doall amino acids contain
Carbon
Oxygen
Hydrogen
Nitrogen
What do some amino acids contain
Sulfur (alongside C,H,O,N)
What are amino acids linked by
Peptide bonds
Amino acids and peptide bonds form to make
Dipeptides and polypeptides
What is released during the reaction when amino acids are joined together
A molecule of water - condensation reaction
The reverse reaction of when peptide bonds between amino acids breaks does what
Adds a molecule of water - hydrolysis reaction
What are the four structural levels of protein
Primary
Secondary
Tertiary
Quaternary
What is the primary structure of a protein
The sequence of the amino acids in the polypeptide chains
What is the secondary structure
hydrogen bonds form between amino acids in the chain. This automatically coils into an alpha helix or fold into a beta pleated sheet
What is tertiary structure
The coiled or folded chain of amino acids is often coiled and folded further. For proteins made from a single polypeptide chain the tertiary formed their final 3D structure
What is quaternary structure
Some proteins are made from several polypeptide chains held together by bonds. For proteins made from more than one polypeptide chain, the quaternary is the protein final 3D structure
What is the primary structure held together by
Peptide bonds between the amino acids
Secondary structures are held together by…..
Hydrogen bonds
Tertiary bonds are held together by
Ionic bonds
Disulphide bonds
Hydrophobic or hydrophilic interactions
Hydrogen bonds
In tertiary structure ionic bonds are used to hold it together, what does this mean
These are attractions between negatively charged R-groups and positively charged R-groups on different parts of the molecule
In tertiary structure disulphide bonds are used to hold it together, what does this mean
Whenever two molecules of the amino acid cysteine come close together, the sulfur atoms in one cysteine, bonds to the sulfur in the other cysteine forming a disulphide bond
In tertiary structure a hydrophobic and hydrophilic interactions holds the structure together. What does this mean
When hydrophobic r groups are close together in the protein, they tend to clump together. This means that hydrophilic r-groups are more likely to be pushed to the outside, which affects how the protein folds up into final structure.
In tertiary structure, hydrogen bonds are used to hold up the structure, what does this mean
Weak bonds form between slightly positively charged hydrogen atoms in some r groups and slightly negative charged atoms in other r groups on the polypeptide chain.
A quarternary structure is held together by
tends to be determined by the tertiary structure of the individual polypeptide chains being bonded together. can be influenced by all the bonds mentioned e.g. ionic, disulphide, hydrophobic and hydrophilic interactions and hydrogen bonds
In a globular protein what tends to be pushed on the outside of the molecule
The hydrophilic r-groups
What causes the globular protein to push the hydrophilic r-group on the amino acids to the outside of the molecule
The hydrophobic and hydrophilic interactions in the tertiary structure
are globular protein soluble
yes meaning they are easily transported in fluids
examples of globular proteins are
haemoglobin
insulin
amylase
what are the properties of a fibrous protein
-insoluble
-strong
-fairly unreactive
what are the example of fibrous proteins that we need to know
collagen
keratin
elastin
where is collagen found
animal connective tissues (bone, skin, muscle etc.)
what can bind to the protein to increase rigidity
minerals
where is keratin found
in many external structures of animals, such as skin, hair, nails etc.
keratin can either be
-flexible (as it is in skin)
-hard and tough (as it is in nails)
where is elastin found
in connective tissue, such as skin, blood vessels, and some ligament
a change in one amino acids in the primary structure means what
a change in one amino acid may change the structure of the whole protein
different protein have….
different sequences of amino acids in their primary structure
