DNA Flashcards
What is DNA?
DNA is a molecule that determines an organism’s characteristics and is a polymer of nucleotides.
What is the structure of DNA?
DNA is made up of many nucleotides made up of sugar (deoxyribose), phosphate, and a base. The DNA molecule is double-helix similar to that of a twisted ladder.
What are the four bases and their complements?
Adenine - Thymine and Cytosine - Guanine.
What are chromosomes?
Chromosomes are lengths of DNA that contain a particular sequence of genes.
What are genes?
Genes are sections of DNA arranged along the chromosomes and are organised in specific places along the chromosomes, called loci.
What does DNA do in terms of protein synthesis?
An organism’s DNA codes for the production of a particular amino acid which then synthesises a particular protein.
What is a codon?
A codon (or triplet) is a group of 3 bases that code for a specific amino acid.
What is a genetic mutation?
They are alterations of genes that often result in a loss of function.
How do alterations in genes cause a change in function?
Alterations in genes result in a change of code which means that different amino acid is produced, thus resulting in a change of the protein produced, changing its function.
What are the different types of genetic mutations?
Silent, Missense, Nonsense and Frameshift (involving insertion + deletion)
What is a silent mutation?
It is when a mutation has no observable effect on the organism’s phenotype.
What is phenotype?
An organism’s observable characteristics.
What is a missense mutation?
It is when the wrong amino acid is produced as a result of a changed codon.
What is a nonsense mutation?
It is when a change in a codon is mutated to produce a protein that causes an end to its translation and is called a premature stop codon.
What are the two types of frameshift?
Insertion and deletion
What is an insertion mutation?
It is when a nucleotide base pair is added to the DNA sequence.
What is a deletion mutation?
It is a mistake in the DNA replication process that removes nucleotides from the genome.
What is a genome?
It is an organism’s complete set of genetic instructions.
What is a mutagen?
They are substances that increase the mutation rate for cells during replication.
What can mutagens cause?
They can cause a change in a single base causing a point mutation.
or they can delete or insert one or more bases causing a frameshift mutation.
