DNA & Proteins Flashcards
(21 cards)
order of protein synthesis
- DNA replication
- Transcription
- Translation
- Post-transcriptional modifications
Amino acids
- joined covalently by peptide bonds
- proteins = polypeptide chains
(layers) structure of proteins
primary, secondary, tertiary & quaternary
Primary structure of proteins
sequence of a chain of amino acids
Secondary structure of proteins
- H bonding of peptide backbone causes folding into repeating patterns
- beta pleated sheets or alpha helix
Tertiary structure of proteins
- 3D folding
- due to interactions between the R groups of the amino acids that make up the protein (H bonding)
Quaternary structure of proteins
- proteins consisting of more than 1 amino acid chain
- further H bonding
electrostatic bonds
- bonds between positively & negatively charged groups
- stabilise tertiary structure of proteins
Van Der Waals interaction
non-covalent attraction due to movement of ions in atomic/molecular orbitals
denaturation
structural changes in proteins that result in loss of biological properties
function of proteins in the body with examples
- Defensive (antibodies)
- Structural (keratin)
- Catalytic (enzymes)
- Transport (haemoglobin)
- Storage (ferritin)
- Messenger (hormones)
- Receptors (insulin receptor)
cofactors
- nonprotein chemical entities
- help to catalyse reactions
- tend to be metal ions or organic compounds
metalloenzymes
metal ions embedded in organic compounds
factors affecting enzyme reactions
- substrate concentration
- enzyme concentration
- temperature
- pH
structure of nucleotide
Purines
- adenine & guanine
- 2 rings
Pyrimidines
- thymine & cytosine
- uracil
- 1 ring
nucleotide base pairing in DNA
- Adenine + Thymine (AT)
- Guanine + Cytosine (GC)
unique base to RNA
Uracil (replaces Thymine)
DNA
- double helix
- bi-polymers of nucleotides
- joined by phosphodiester bonds (3’ & 5’)
- slightly acidic
histone proteins
anchor & support DNA
