DNA and Chromosomes Flashcards
What is a gene?
A section of DNA that contains a code for making a polypeptide and functional RNA.
How do genes determine the proteins of an organism?
Polypeptides make proteins.
What is a locus?
The location of a particular gene on a chromosome.
What is an allele?
Different forms of a gene.
How is DNA stored in eukaryotes?
In chromosomes.
What are chromosomes?
Tightly coiled DNA.
How many chromosomes do humans have?
23 pairs (46)
What are homologous chromosomes?
Chromosomes that carry the same genes.
To fit the DNA in the nucleus as chromosomes what is done?
The DNA is tightly wound around histones.
Contrast prokaryotic and eukaryotic DNA? (4)
Eukaryotic DNA is linear. Prokaryotic DNA is circular.
Eukaryotic DNA is longer. Prokaryotic DNA is shorter.
Eukaryotic DNA is associated with proteins. Prokaryotic DNA is not.
Eukaryotic DNA has introns. Prokaryotic DNA doesn’t.
Similarities between prokaryotic and eukaryotic DNA? (3)
Identical nucleotide structure.
Nucleotides joined by phosphodiester bonds.
DNA in mitochondria and chloroplasts is similar to DNA in prokaryotes.
How are DNA in mitochondria and chloroplasts similar to DNA in prokaryotes?
Short
Circular
Not histone bound.
Function of a histone protein?
To associate with the DNA to assist in tightly coiling DNA to fit chromosomes in the nucleus.
