Ch. 10 - The Structure and Function of DNA Flashcards
Adenine (A)
A double-ring nitrogenous base found in DNA and RNA.
AIDS
Acquired immunodeficiency syndrome; the late stages of HIV infection, characterized by a reduced number of T cells; usually results in death caused by opportunistic infections.
anticodon
On a tRNA molecule, a specific sequence of three nucleotides that is complementary to a codon triplet on mRNA.
Bacteriophage
A virus that infects bacteria; also called a phage.
cap
Extra nucleotides added to the beginning of an RNA transcript in the nucleus of a eukaryotic cell.
Codon
A three-nucleotide sequence in mRNA that specifies a particular amino acid or polypeptide termination signal; the basic unit of the genetic code.
cytosine (C)
A single-ring nitrogenous base found in DNA and RNA.
DNA
The genetic material that organisms inherit from their parents; a double-stranded helical macromolecule consisting of nucleotide monomers with deoxyribose sugar, a phosphate group, and the nitrogenous bases adenine (A), cytosine (C), guanine (G), and thymine (T). See also gene.
DNA polymerase
An enzyme that assembles DNA nucleotides into polynucleotides using a preexisting strand of DNA as a template.
double helix
The form assumed by DNA in living cells, referring to its two adjacent polynucleotide strands wound into a spiral shape.
emerging virus
A virus that has appeared suddenly or has recently come to the attention of medical scientists.
Exon
In eukaryotes, a coding portion of a gene. See also intron.
genetic code
The set of rules giving the correspondence between nucleotide triplets (codons) in mRNA and amino acids in protein.
guanine (G)
A double-ring nitrogenous base found in DNA and RNA.
HIV
Human immunodeficiency virus; the retrovirus that attacks the human immune system and causes AIDS.
Intron
In eukaryotes, a nonexpressed (noncoding) portion of a gene that is excised from the RNA transcript. See also exon.
lysogenic cycle
A bacteriophage reproductive cycle in which the viral genome is incorporated into the bacterial host chromosome as a prophage. New phages are not produced, and the host cell is not killed or lysed unless the viral genome leaves the host chromosome.
lytic cycle
A viral reproductive cycle resulting in the release of new viruses by lysis (breaking open) of the host cell.
messenger RNA (mRNA)
The type of ribonucleic acid that encodes genetic information from DNA and conveys it to ribosomes, where the information is translated into amino acid sequences.
molecular biology
The study of the molecular basis of heredity; molecular genetics.
Mutagen
A chemical or physical agent that interacts with DNA and causes a mutation.
