AS: Section 1 - Biological Molecules, DNA and Enzymes. Flashcards
What charge do the hydrogen and oxygen atoms have in a water molecule and what does this make the molecule?
Hydrogen: positive
Oxygen: negative
Overall: polar
Why is water vital to living organisms?
It is a reactant in loads of important chemical reactions.
It is a solvent.
It transports substances.
Helps with temperature control
What does water being polar allow the water molecules to form between each other?
Hydrogen bonds
How are amino acids bonded together?
By peptide bonds
What is a condensation reaction?
When a peptide bond forms between two amino acids and a water molecule is removed.
What is a hydrolysis reaction?
The addition of a water molecule to break a peptide bond.
What is the primary structure of an amino acid?
A sequence of amino acids in a polypeptide chain - held together using peptide bonds.
What is a secondary structure of a protein?
A polypeptide chain doesn’t remain flat and straight, and hydrogen bonds form between amino acids in the chain. Causing them to coil into an alpha helix, or fold into a beta pleated sheet.
What three groups are an amino acid composed of?
A amino group: H2N
A carboxyl group. COOH
A variable group. R
What is the tertiary structure of a protein? And what are the bonds that hold it together?
The coiled or folded chain if amino acids are coiled or folded further. More bonds form between different parts of the polypeptide chain.
Bonds formed:
Ionic interactions - weak attractions between negative and positive charges on different parts of the molecule.
Disulphide bonds - when two cysteine amino acids come together, the sulfur atom on one cysteine bonds to another, causing a disulphide bond.
Hydrophilic and hydrophobic interactions.
Hydrogen bonds.
What is the Quaternary structure of an amino acid?
The final 3D structure of a protein which is composed of many polypeptides held together by bonds.
How does the shape of collagen relate to its function?
Its a fibrous protein that forms supportive tissues in animals.
Made of three polypeptide chains that are tightly coiled into a strong triple helix.
The chains are interlinked by covalent bonds.
How does the shape of haemoglobin relate to its function?
A globular protein with an iron containing haem group that can bind to oxygen.
Curled up due to hydrophilic side chain being on the outside and hydrophobic side chains being on the inside.
Haemoglobin is soluble in water, which makes it great for transport in the blood.
