DNA, Genes and Chromosomes Flashcards
1
Q
What is nuclear Eukaryotic DNA?
A
- Linear
- Associated with proteins called histones
- Coiled up tightly with with protein to make a compact chromosome
2
Q
DNA molecules in prokaryotes.
A
- Still carry DNA as chromosomes - but DNA molecules are shorter and circular
- DNA isn’t wound around histones - it condenses to fit in the cell by super-coiling.
3
Q
What is a gene?
A
- A sequence of DNA bases that codes for either a polypeptide or functional RNA.
- The sequence of amino acids in a polypeptide forms the primary structure of a protein.
4
Q
What do genes that don’t code for polypeptide code for instead?
A
- Functional RNA. Which is RNA molecules other than mRNA, which perform special tasks during protein synthesis.
- E.g. tRNA and rRNA.
5
Q
What is the name of a section of DNA which doesn’t code for amino acids?
A
- Introns
6
Q
What is the name of a section of DNA which does code for amino acids?
A
- Exons
7
Q
Where and how are introns removed?
A
- Protein Synthesis
- Splicing
8
Q
Does prokaryotic DNA have introns?
A
- No.
9
Q
What are regions of multiple repeats outside of genes?
A
- DNA sequences that repeat over and over.
- E.g. CCTTCCTTCCTT
- These areas don’t code for amino acids either, so they’re called non-coding repeats.
10
Q
What is an allele?
A
- A gene that exists in more than one form.
- The order of bases in each allele is slightly different, so they code for slightly different versions of the same polypeptide.
