Chapter 10 Vocabulary

Mutation

A change in the nucleotide base-sequence of a gene or a DNA molecule.

Ribose

A five-carbon sugar present in RNA.

Deoxyribose

A five-carbon sugar that is a component of DNA nucleotides.

Pyrimidine

A nitrogenous base that has a single-ring structure; one of the two general nitrogenous bases found in DNA and RNA; either thymine, cytosine, or uracil.

Anticodon

A region of tRNA that consists of three bases complementary to to the codon of mRNA.

Bacteriophage

A virus that infects bacteria.

tRNA (transfer RNA)

An RNA molecule that transfers amino acids to the growing end of a polypeptide chain during translation.

Nitrogenous Base

An organic base that contains nitrogen, such as a purine or pyrimidine; a subunit of a nucleotide in DNA and RNA.

Virulent

Describes a microorganism that causes disease and that is highly infectious; strictly, refers only to viruses that reproduce by the lytic cycle.

Codon

In DNA, a three-nucleotide sequence that encodes an amino acid or signifies a start singal or a stop signal.

Nucleotide

In a nucleic-acid chain, a subunit that consists of a sugar, a phosphate, and a nitrogenous base.

Semi-Conservative Replication

In each new DNA double helix, one strand is from the original molecule, and one strand is new.

Genome

The complete genetic material contained in an individual.

Protein Synthesis

The formation of proteins by using information contained in DNA and carried by mRNA.

Complementary Base Pair

The nucleotide bases in one strand of DNA or RNA that are paired with those of another strand; adenine pairs with thymine or uracil, and guanine pairs with cytosine.

Base Sequence

The order of nitrogenous bases on a chain of DNA.

Genetic Code

The rule that describes how a sequence of nucleotides, read in groups of three consecutive nucleotides (triplets) that correspond to specific amino acids, soecifies the amino acid sequence of a protein.

Base-Pairing Rules

The rules stating that cytosine pairs with guanine and adenine pairs with thymine in DNA, and that adenine pairs with uracil in RNA.

Replication Fork

The Y shaped region where the DNA splits.

Translation

The portion of protein synthesis that takes place at ribosoomes and that uses the codons in mRNA molecules to specify the sequence of amino acids in polypeptide chains.

DNA Replication

The process by which DNA is copied in a cell before a cell divides by mitosis, meiosis, or binary fission.

Transcription

The process of forming a nucleic acid by using another molecule as a template; particularly the process of synthesizing RNA by using one strand of a DNA molecule as a template.

Transformation

The transfer of genetic material in the form of DNA fragments from one cell to another or from one cell to another or from one organism to another.

Ribonucleic Acid (RNA)

A natural polymer that is present in all living cells and that plays a role in protein synthesis.

Purine

A nitrogenous base that has a double-ring structure; one of the two general categories of nitrogenous bases found in DNA and RNA; either adenine or guanine.

Promoter

A nucleotide sequence on a DNA molecule to which an RNA polymerase molecule binds, which initiates the transcription of a specific gene.

mRNA (messenger RNA)

A single stranded RNA molecule that encodes the information to make a protein.

Termination Signal

A specific sequence of nucleotides that marks the end of a gene.

DNA Polymerase

An enzyme that catalyzes the formation of the DNA molecule.

Helicase

An enzyme that seperates DNA strands.

RNA Polymerase

An enzyme that starts (catalyzes) the formation of RNA by using a strand of a DNA molecule as a template.

rRNA (ribosomal RNA)

An organelle that contains the most of the RNA in the cell and that is responsible for ribosome function.