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How genes work ch. 15

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gene expression
the process of converting archived information into molecules that actually do things in the cell.
the one-gene, one-enzyme hypothesis
ach gene is made of only one enzyme
knock-out mutants
alleles that do not function at all
mRNA
messenger RNA are short-lived molecules that carry info from DNA to the site of protein synthesis
RNA polymerase
polymerizes ribonucleotides into strands of RNA.
central dogma
summarizes the flow of info in cells. an accepted version of the way things are/happen.
Transcription
the process of copying hereditary information in DNA to RNA.
Translation
the process of using the information in nucleic acids to synthesize proteins.
genetic code
the rules that specify the relationship between a sequence of nucleotides in DNA or RNA and the sequence of amnio acids in a protein.
triplet code
a three-base code
codon
the group of three bases that specifies a particular amino acid
start codon
signals that protein synthesis should begin at that point on the mRNA molecule.
stop codon
termination codons that signal the protein is complete and end the translation process.
mutation
any permanent change in an organism's DNA
point mutation
a single base change
missense mutations
a point mutation that causes a change in the amino acid sequence of a protein. Change in primary polypeptide structure. ch
silent mutations
a point mutation that does not change the amino acid sequence of the gene product. A change in the genotype but not the phenotype
nonsense mutation
change in nucleotide that results in early stop codon
beneficial
increase the fitness of the organism
neutral
mutation has no affect on fitness
deleterious
lower fitness
frameshift
addition or deletion of a nucleotide
polyploidy
a change in the number of each type of chromosome present
aneuploidy
the addition or deletion of a chromosome
inversion
segments become flipped and rejoin
translocation
become attached to a different chromosome
karyotype
the complete set of chromosomes in a cell