4: GENETICS - DNA, GENES AND CHROMOSOMES Flashcards
How is DNA stored in eukaryotic cells?
- wound around histone proteins
- DNA with proteins coiled up repeatedly to form chromosomes
How is DNA stored in mitochondria and chloroplasts?
circular chromosomes (similar to prokaryotic DNA)
How is DNA stored in prokaryotic cells?
- shorter, circular chromosomes
- DNA condenses to fit in the cell by supercoiling
Compare the structure and organisation of eukaryotic and prokaryotic DNA (4 marks)
- eukaryotic - very long, linear DNA molecules
- prokaryotic - short, circular DNA molecules
- eukaryotic - DNA associated proteins
called histones, DNA wound around histones, then coiled tightly to make compact chromosome that are located in nucleus
- prokaryotic – no associated proteins , DNA condenses by supercoiling into chromosome
What is a gene?
a sequence of DNA bases that codes for a polypeptide/functional RNA
What determines the order of amino acids in a particular polypeptide?
the order of bases in a gene
How many bases code for 1 amino acid?
3
What is the name of the sequence of bases in a gene that code for an amino acid?
a DNA triplet
What is functional RNA?
RNA molecules other than mRNA and rRNA
What is genome?
the complete set of genes in a cell
What is proteome?
the full range of proteins that a cell is able to produce
What are sections of DNA that don’t code for amino acids called?
introns
Do eukaryotic cells have introns?
yes
Do prokaryotic cells have introns?
no
What are sections of DNA that do code for amino acids called?
exons
