Unit 1.3 DNA Flashcards
DNA
Responsible for inheritance and for controlling cells by organising protein synthesis.
Chromosomes and plasmids are made of DNA. It is found in the nucleus.
DNA structure
A double stranded molecule twisted into a helix (spiral).
It carries genetic information in its sequence of bases.
DNA bases
Make up the central part of the DNA molecule.
They are arranged in complementary (matching) pairs : A-T and C-G
They carry genetic information as a genetic code.
Genetic code
The sequence of bases in the part of a DNA molecule which is known as a gene.
Gene
A section of DNA which codes for a protein by determining its amino acid sequence.
eg. the insulin gene contains the instructions for building insulin.
Protein
A large molecule made of individual amino acids, which are joined together with chemical bonds to form a chain, which is then folded.
Amino acids
The building blocks of proteins.
There are 20 different types of amino acid, which combine to produce a huge variety of proteins.
The amino acid sequence determines how a protein folds, so must be correct every time.
Codon
A block of 3 bases on mRNA which codes for a specific amino acid.
mRNA
A messenger molecule, made by copying the base sequence of a gene.
It carries a complementary copy of the genetic code from the nucleus to the cytoplasm, where it joins onto a ribosome.
Ribosome
A structure found in the cytoplasm, which translates the code carried by the mRNA into an amino acid sequence in a protein.