4.1 DNA, Genes + Chromosomes Flashcards
DNA in eukaryotes vs prokaryotes: Length
Longer vs shorter
DNA in eukaryotes vs prokaryotes: Shape
Linear vs circular
DNA in eukaryotes vs prokaryotes: number of strands per cell
Multiple strands vs 1 strand
DNA in eukaryotes vs prokaryotes: Association with proteins
Histones vs no
DNA in eukaryotes vs prokaryotes: All coding DNA?
No (has introns) vs Yes
What are chromosomes
A DNA molecule associated around histone proteins
What type of DNA do mitochondria and chloroplasts contain
Prokaryotic
Define a gene
A sequence of DNA bases that codes for a polypeptide
What is the name of the place where a gene occupies a fixed position on a chromosome
Locus
What is a locus
The fixed position that a gene occupies on a chromosome
How is DNA read
In triplets
How many bases of DNA is a triplet
3
What does each triplet code for
An amino-acid
3 bases is what in a mRNA and anti-tRNA
Codon and Anti-codon
What does DNA being described as Universal mean
The same triplets code for the same amino acids in all species
What does DNA being described as Degenerate mean
Many different triplets code for 1 amino-acid
What does DNA being described as Non-Overlapping mean
Each base is only part of 1 triplet
In eukaryotes, does all the DNA code for polypeptides
- No
- Exons do
- Introns don’t
In eukaryotes, when are the introns removed
Splicing of pre-mRNA
How does a gene code for the production of a polypeptide
- The gene contains a sequence of DNA bases
- 3 bases are a triplet
- DNA is read in triplets
- Each triplet codes for an amino-acid
- Triplets determine the order and sequence of amino-acids in the polypeptide
