GI: DNA, Genes and Chromosomes Flashcards
What type of DNA do eukaryotic cells contain?
Long, linear DNA molecules that exist as chromosomes, wound around proteins called histones.
DNA and histone is coiled very tightly to make a compact chromosome.
Within eukaryotic cells, what else have their own DNA?
What is this similar to?
Mitochondria and chloroplasts.
Similar to prokaryotic DNA - circular and shorter than molecules in nucleus. Not associated with histones.
What is DNA wound around in eukaryotic cells?
What does this do?
Histones.
Histone proteins helo support the DNA.
Describe DNA within prokaryotes:
DNA as single circular strand.
Molecules are shorter than eukaryotes and circular.
Not wound around histones - condenses to fit in cell by supercoiling.
How does prokaryotic DNA fit into the cell:
By supercoiling
Gene
Sequence of DNA bases that codes for either a polypeptide or functional RNA.
Genome
Complete set of genes in the cell.
Proteome
Full range of proteins that the cell is able to produce.
Sequence of DNA bases that codes for either a polypeptide or functional RNA.
Gene
Complete set of genes in the cell.
Genome
Full range of proteins that the cell is able to produce.
Proteome
What forms the primary sturcture of a protein?
The sequence of amino acids in a polypeptide.
What determines the order of amino acids in a polypeptide?
The order of bases in a gene.
What is each amino acid coded by?
Sequence of three bases in a gene called a triplet.
If genes don’t code for a polypeptide, what do they code for instead?
A functional RNA
Functional RNA
RNA molecules other than mRNA, which perform special tasks during protein synthesis, eg. tRNA and ribosmal rRNA.
RNA molecules other than mRNA, which perform special tasks during protein synthesis, eg. tRNA and ribosmal rRNA.
Functional RNA
Does most DNA in eukaryotic cells code for polypeptides of functional RNA?
Functional RNA
Introns
Sections of DNA that don’t code for amino acids.
Exons
Sections of DNA that do code for amino acids.
Sections of DNA that don’t code for amino acids.
Introns
Sections of DNA that do code for amino acids.
Exons
Does prokaryotic DNA have introns?
No
What happens to introns in DNA?
They are removed during protein synthesis - so don’t affect amino acid order.
Do introns affect amino acid order?
No as they are removed during protein synthesis.
Apart from introns and exons, what else does eukaryotic DNA also contain?
Multiple repeats that are outside of genes - don’t determine amino acid sequence.
What are multiple repeats?
DNA sequences that repeat over and over.
Don’t code for amino acids and so are non-coding repeats.
Allele
Alternate form of a gene.
What differs between alleles of the same gene?
The order of bases is slightly different, so they code for slightly different versions of the same polypeptide.
Homologous pairs
Pairs of matching chromosomes
