DNA Flashcards
DNA is…
- Universal (same specific base triplets code for same amino acids in all living organisms)
- Non-overlapping (base triplets don’t share their bases)
- Degenerate (64 possible triplets so some code for same AA)
How is DNA stored in eukaryotes?
Long, linear DNA molecules that exist as chromosomes, found in the nucleus. Wound around proteins called histones, coiled up very tightly to make a compact chromosome. Introns present
How is DNA stored in prokaryotes?
DNA molecules are shorter and circular. The DNA isn’t wound around histones, it condenses to fit in the cell by supercoiling. Introns not present
What is a gene?
A sequence of DNA bases that codes for a polypeptide or functional RNA. The order of bases in a gene determines the order of amino acids
What is functional RNA?
RNA molecules other than mRNA which perform specific tasks during protein synthesis (eg. tRNA)
What are alleles?
Different forms of the same gene (they code for slightly different versions of the same polypeptide)
What is the proteome?
The full range of proteins the cell is able to produce
How is each amino acid coded for?
By a sequence of 3 bases on a gene (triplet/codon)
What are introns?
Base sequences of DNA that don’t code for amino acids
What are non-coding multiple repeats?
DNA that doesn’t code for amino acids positioned between genes
How many chromosomes do humans have?
23 pairs (pairs of matching chromosomes are called homologous pairs)
Locus
The fixed position occupied by a gene on a DNA molecule
