dna replication, protein synthesis, epigenetics Flashcards
what is dna
Dna is deoxyribonucleic acid. composed of nucleotides which are polymers. they contain deoxyribose molecule (sugar), phosphate group and nitrogenous base (either adenine, thymine, guanine, or cytosine).
It is a specialised chemical molecule that has the ability to carry genetic information
difference between chromatin and chromosomes
chromatin is a tangled network of coiled DNA (DNA soup)
chromosomes are rod shaped structures consisting of tightly coiled DNA around histones
key facts about mitochondrial dna
originates from the mother only (fertilisation)
makes us 0.01% of DNA
circular DNA (originates from bacteria)
37 genes (24 is used to make tRNA and 13 are utilised for cellular respiration)
What are enzymes involved in DNA Replication and what is their purpose?
DNA TOPOISOMERASE - untwist
DNA HELICASE - separate the DNA molecule into leading and lagging strands
DNA PRIMASE - adds short sequence of RNA base to leading/lagging strand as a primer in preparation (polymerase)
DNA POLYMERASE - adds nucleotide bases to the leading/lagging strand in the 5-3 direction, also proof checks for any errors to minimise mutations.
DNA LIGASE - connects short segments together (Okazaki Fragments)
formation of proteins order
primary structure: polypeptide chain composed of amino acids
secondary structure: hydrogen bonds form to create substructures
tertiary structure: non-covalent interactions between molecules
quaternary structure: 2 or more tertiary structures form this
Messenger RNA characteristics NAME
mrna produced in nucleus leaves through nuclear pores to site of protein synthesis uncoiled long straight chain complementary to DNA 500-1000 nucleotides
Transfer RNA characteristics NAME
tRNA produced in nucleus stays there until needed for translation clover leaf shape a small single folded strand with an attachment site for amino acid and contains a anti-codon
