protiens

What are essential amino acids

Amino acids that cannot be synthesized or produced by the human body and must be obtained from the diet

How many amino acids cannot be made by the body

KEYWORD CANNOT

9

What are non essential amino acids and how many

Non-essential amino acids are amino acids that your body can synthesise itself.

11

Conditional amino acids

Conditional amino acids are those amino acids that while not essential may become so in times of stress or sickness

How is a peptide bond formed?

Two amino acids undergo a condensation reaction. An OH from the carboxyl group and H from the amino group combine to form water, which is removed, leaving a peptide bond between the amino acids.

A dipeptide means a molecule made from two amino acids joined together by a peptide bond.

what’s a hydrogen bond

A weak attraction between a slightly positive hydrogen atom and a slightly negative atom, usually oxygen or nitrogen.

What happens to hydrogen bonds when temperature or pH changes?

They can break and reform, potentially changing the protein’s structure.

Potentially bc it won’t necessarily break but it MAY

How does a disulfide bond form?

Two cysteine residues in a polypeptide are brought close together. An oxidation reaction occurs between their sulfur-containing groups, forming a strong covalent S–S (disulfide) bond. This helps maintain the protein’s folded 3D structure.

Ionic bonds can form between

oppositely charged R groups

R+ R- when they come close together

Are hydrogen bonds covalent bonds

No they are a weak attraction between partially charged atoms .it is not the same as covalent bonds

Arrange them in strongest to least strongest

Disulfide ionic hydrogen

1.disulfide -covalent s-s bond strongest

2.ionic -electrostatic attraction stronger

3.hydrogen weak weakest

How temperature ph affect these

Hydrogen

Disulfide bonds

Ionic bonds

Hydrogen bonds are week and can be disrupted by changes in temperature and ph

Ionic bonds can be disrupted by changes in ph because the ph can affect the charges on on R groups .temp can also disrupt but not necessarily important

Disulfide bonds are strong covalent bonds and much harder to disrupt

What is a zwitterion?

A zwitterion is an amino acid with both a positive and negative charge on different functional groups, but with no overall charge. In aqueous solution, the amino group gains H⁺ to become NH₃⁺, while the carboxyl group loses H⁺ to become COO⁻.

What are the four levels of protein structure?

Primary, secondary, tertiary and quaternary.

What are the primary and secondary structures of a protein?

🧠 Primary: The specific sequence of amino acids in a polypeptide, joined by peptide bonds.

🧠 Secondary: The polypeptide chain folds into α-helices or β-pleated sheets, which are held in place by hydrogen bonds.

Characteristics of fibrous proteins

.long ——

.parallel = polypeptide chains

.tough and insoluble in water. 💦

Collagen is an example

What does high tensile strength mean

meaning it can resist being pulled apart/stretched.

Describe the structure of collagen.

Collagen is made of three long polypeptide chains.⛓⛓

These three chains twist around each other to form a triple helix.🧬

The three chains are held together by many hydrogen bonds.🧬⛓

The collagen molecules then group together into fibrils, and the fibrils group together to form collagen fibres.🧬⛓🧬⛓🧬⛓→🖍

What is the function of collagen?

Collagen is a structural protein that gives tissues strength and high tensile strength.

It helps tissues such as tendons, ligaments, skin and bones withstand forces such as pulling and stretching.

What is tertiary structure

The further folding of a polypeptide chain into a specific three-dimensional shape, maintained by interactions between R groups, including hydrogen, ionic and disulfide bonds

GLOBULAR PROTEINS

Globular proteins are proteins that fold into a compact, roughly spherical 3D shape.

They have a complex tertiary structure, and some also have quaternary structure.

Explain why hydrophobic R groups are found inside globular proteins.

Hydrophobic R groups repel/do not interact favourably with water → they become positioned away from the surrounding water → they are found towards the inside of the globular protein.

Hydrophilic

Hydrophilic R groups have an affinity for water → they can interact with surrounding water → they tend to be positioned on the outside.

What is a colloid?

A colloid is a mixture where very small particles of one substance are suspended throughout another substance.

Example of globular proteins

Antibodies

What forms the α-helix and β-pleated sheet?

hydrogen bonds between nearby parts of the polypeptide backbone.

What is a prosthetic group?

A prosthetic group is a non-protein component that is permanently attached to a protein.

What are glycoproteins

"They are proteins with a carbohydrate prosthetic group.

* The carbohydrate part of the molecule helps them to hold a lot of water and also makes it harder for protein-digesting enzymes (proteases) to break them down.

Lots of lubricants used by the human body - such as mucus and the synovial fluid in the joints - are glycoproteins.