Chapter 16- How Genes Work

Transcription

________ is the process of using a DNA template to make an RNA molecule that has a base sequence complementary to the DNA.

viral enzyme

A(n) ________ called reverse transcriptase synthesizes a DNA version of the RNA genes.

single addition

A(n) ________ or deletion throws the sequence of codons, or the reading frame, out of register.

central dogma

The ________ summarizes the flow of information from DNA to proteins.

Translation

________ is the process of using the information in the base sequence of mRNA to synthesize proteins.

genetic screen

A(n) ________ is any technique for picking particular types of mutants out of many randomly generated mutants.

Errors

________ in crossing over or in DNA synthesis can lead to the presence of one or more additional copies of a segment which is a duplication.

DNA

If a change in ________ sequence leads to a change in the third position of a codon, it is less likely to alter the amino acid in the protein.

Information

________ in the messenger RNA is translated into proteins by ribosomes.

Point mutations

________ and chromosome mutations are random changes in DNA that can produce new genes, alleles, and traits.

particular amino acid

A group of three bases that specifies a(n) ________ is called a codon.

Alleles

________ that do not function at all are called null alleles, or loss- oιfunction ________.

mutation

A(n) ________ is any permanent change in an organisms DNA.

Stop codons

________ do not code for any amino acid but signal the end of the reading frame and therefore, the end of the polypeptide.

DNA

________ is transcribed to RNA by RNA polymerase.

One-gene, one-enzyme hypothesis

Beadle and Tatum proposed that each of the mutants could not make a particular compound because it lacked an enzyme required to synthesize the compound

Triplet code

A three-base code, known as a triplet code, is the shortest genetic word to code for at least 20 amino acids.

Genetic code

is the rules that specify the relationship between a sequence of nucleo des in DNA or RNA and 1e sequence of amino acids in a protein.

One-gene, one-enzyme hypothesis

Beadle and Tatum proposed that each of the mutants could not make a particular compound because it lacked an enzyme required to synthesize the compound.

Start codons

set the reading frame of the message, locking in which set of three-base triplets constitute “words.