DNA, Genes And Protein Synthesis Flashcards
What are 4 features of the genetic code?
Degenerate
Non-overlapping
Universal
Read in triplets (codons)
What is meant by the term degenerate?
More than one triplet codes for the same amino acid
What is meant by non-overlapping?
Each base is read once (as part of a triplet)
What is meant by universal?
The same triplet always codes for the same amino acid in living organisms
Describe the structure of DNA?
Made of DNA nucleotides containing deoxyribose, phosphate and nitrogenous base (A,C,T,G)
It is double stranded and hydrogen bonds between complementary base pairs form a helix shape
How is DNA in eukaryotic cells different to prokaryotic cells?
DNA in eukaryotes is long and linear, associated with histone proteins to form chromosomes
DNA in prokaryotes is shorter, circular and not associated with histone proteins
What is the genetic code?
The order of bases on DNA, consists of codons (triplets of bases that code for a particular amino acid
Define the term gene?
A sequence of bases on a DNA molecule that codes for a specific sequence of amino acids (polypeptide)
Define the term genome?
The complete set of genes in each cell of an organism
Define the term proteome?
The full range of proteins produced by the genome in that organism
What is a locus?
The fixed position on a chromosome occupied by a gene
What is an allele?
Different versions of the same gene, found at the same locus on a chromosome
What are exons and introns?
Exons = regions of DNA that code for amino acid sequences
Introns = non-coding regions of DNA
Where are introns located?
Introns are only present in eukaryotes not prokaryotes
They are found between exons in genes
What are the two different types of mutation?
Gene mutations
Chromosomes mutation
What are the two types of gene mutation?
Point mutation
Frame shift
What is a mutation?
A random change/alteration to the DNA base sequence which occurs randomly during DNA replication
What is a point mutation and give an example?
The mutation just effects one nucleotide/base
A base substitution ( a nucleotide in the DNA is replaced by another)