DNA , genes and chromosomes Flashcards
What does DNA look like in prokaryotic cells?
In prokaryotic cells, DNA is short, circular, and not associated with proteins.
What is DNA like in eukaryotic cells?
In the nucleus of eukaryotic cells, DNA molecules are long, linear, and associated with proteins called histones. Together a DNA molecule and its associated proteins form a chromosome.
In eukaryotic cells, what do mitochondria and chloroplasts contain?
DNA
What is a gene?
A base sequence for DNA
What do genes code for?
- the amino acid of a polypeptide
- a functional RNA (including ribosomal RNA and tRNA ).
What does a gene occupy?
A gene occupies a fixed position, called a locus, on a particular DNA molecule.
What is a sequence of three DNA bases?
Called a triplet, codes for amino acids. The genetic code is universal, non-overlapping, and degenerate.
How do nucleotides join together?
They join together by phosphodiester bonds formed in condensation reactions.
What does a DNA molecule look like?
A DNA molecule is a double helix composed of two polynucleotides joined together by hydrogen bonds between complementary bases whereas RNA is a relatively short polynucleotide chain.
