Genes And Variation Flashcards
(18 cards)
What is a chromosome?
A DNA molecule and its associated proteins combined together
What is a gene?
A section of DNA that codes for a single protein
What is a histone?
Proteins which DNA is wrapped around, package it into structures called chromosomes
What is an intron?
Sequences of DNA that do not code for amino acid sequences
These are located within a gene
What is an Exon?
Sequences of DNA that code for polypeptides/ amino acid sequences
What is a genome?
The complete set of genes in the cell
What is a proteome?
The full range of proteins that the cell is able to produce
What do we call a fixed position in which a gene occupies?
Locus
What is the sequence of three bases called in DNA which codes for a specific amino acid?
Triplet
How is DNA packaged in eukaryotic chromosomes?
- DNA molecule
- DNA combined with histone proteins
- DNA - histone complex is coiled
- coils fold to form loop
- loops coil and pack together to form a chromosome
Describe DNA in prokaryotes
DNA molecules are shorter
Plasmids - circular DNA
Not associated with protein molecules
Do not have chromosomes
Describe DNA in eukaryotes
- DNA molecules are larger
- linear
- associated with proteins (histones) to form structures called chromosomes
What is the genetic code?
The sequence of bases in DNA codes for sequence of amino acids proteins
How many amino acids do humans have that make up our proteins?
20
What do we mean by degenerate?
Most amino acids are coded by more than one triplet
In terms of the genetic code, what do we mean by ‘it is a non-overlapping code’?
Each base appears in only one triplet
In terms of the genetic code, what do we mean by it being a ‘universal code’?
Genetic code is the same in all known living organisms
Describe the process splicing
During protein synthesis, the entire gene is transcribed
The introns need to be cut out by enzymes
Process is known as splicing
