Ch. 8 Microbial Genetics Flashcards
Genotype
the genetic makeup of an organism
phenotype
expression of the genes
Short tandem repeats (STRs)
repeating sequences of noncoding DNA
Vertical gene transfer
flow of genetic information from one generation to the next
DNA replication
- Topoisomerase and gyrase relax the strands
- Helicase separates the strands
- A replication fork is created
DNA polymerase
adds nucleotides to the growing DNA strand
Energy needs
– Energy for replication is supplied by nucleotides
– Hydrolysis of two phosphate groups on ATP
provides energy
Risbosomal RNA (rRNA)
integral part of ribosomes
Transfer RNA (tRNA)
transports amino acids during protein synthesis
Messenger RNA (mRNA)
carries coded information from DNA to ribosomes
transcription begins when RNA polymerase binds to the
promoter sequence on DNA
transcription stops when it reaches the
terminator sequence on DNA
Codons
groups of three mRNA nucleotides that code for a particular amino acid
61 sense codons
encode the amino acids
degeneracy
each amino acid is coded by sever codons
Start Codon
AUG
Stop codons
UAA, UAG, UGA
tRNA molecules also have an
anticodon that base-pairs with the codon
exons
regions on DNA that code for proteins
introns
regions of DNA that do not code for proteins
small nuclear ribonucleoprotiens (snRNPs)
remove introns and splice exons together
repression
inhibits gene expression and decreases enzyme synthesis
-mediated by repressors, proteins that block transcription
Induction
inhibits gene expression and decreases enzyme synthesis
- initiated by an inducer
Promoter
segment of DNA where RNA polymerase initiates transcription of structural genes