Chapter 7 Flashcards
the science of heredity; structure and function of DNA
genetics
DNA molecule is a double helix composed of repeating monomers called
nucleotides
a segment of DNA that forms a unit of heredity is termed
gene
the complete set of genes for an organism is termed a
genome
bacterial and archaeal DNA is organized within an area of the cytosol called the
nucleoid
what is the shape of a DNA chromosome
circular
because the genome contains only one set of genes, prokaryotes are ________
haploid
essential for cell function; shared by all strains of a species
core genes
have useful functions; shared by several strains of a species
variable genes
unique to one strain of a species
unique genes
carry nonessential but often useful information
plasmids
plasmids are resistant to what two things
antibiotics and heavy metal toxicity
plasmids produce _________ that inhibit other bacterial species
proteins
found only in eukaryotic microbes containing mitochondria and/or chloroplasts
organelle DNA
what are the three stages of DNA replication in the cell cycle
initiation, elongation, and termination
how many daughter strands of DNA exist following replication
two
each of the two DNA double helices contain one old half and one new half
semiconservative replication
in initiation, how many origins of replication do bacteria and eukaryotes have
bacteria- one
eukaryotes- multiple
synthesizes new nucleotide strands of DNA on old template using complementary bases in elongation
DNA polymerase
when the terminus region is reached what process stops
termination
process of using the information in genes to make proteins and other products
gene expression
identifies the flow of genetic material
central dogma
the enzyme responsible for transcribing DNA
RNA polymerase
in initiation, RNA polymerase looks of the __________, where it attaches and unwinds the DNA
promoter
in what process does RNA polymerase add complementary bases to the DNA strand to make a product composed of RNA
elongation
in what process does RNA polymerase stop transcribing at a terminator sequence
termination
what is the location of transcription
nucleoid of prokaryotes
what are the steps in transcription of DNA into RNA
initiation, elongation, and termination
transcription product that carries message in codons to ribosome
mRNA
________ and proteins make up ribosomes
rRNA
caries anticodon complimentary to mRNA message and amino acid to ribosome for protein synthesis
tRNA
what are the stop codons
UAA, UAG, and UGA
what is the stop codon
AUG
the ribosome clamps onto the mRNA at the start codon AUG
chain initiation
tRNAs base pair with the mRNA feeding through the ribosome, and the amino acids they carry are bound together with peptide bonds to form a chain
chain elongation
the process continues until a stop codon is encountered on the mRNA, and the chain is released
chain termination/release
the results of heritable changes in a genome
mutations
mutations can be _______ or _________
spontaneous or induced
one of the most common results of mutagens acting on DNA
point mutation
one incorrect base in mRNA sequence of codons
base-pair substitutions
no change in protein produced due to the redundancy of the genetic code
silent mutation
the wrong amino acid is inserted at the point of the mutation, and the protein may not have the correct shape and function
missence mutation
stop codon at the point of the mutation; the polypeptide is nonfunctional
nonsense mutation
leads to an inappropriate number of bases and a frameshift mutation, where the protein is built abnormally
base-pair deletion or insertion
the transfer of genetic material from parent cell to daughter cell
vertical gene transfer
transfer of DNA from a donor cell to a recipient cell
horizontal gene transfer
what three processes does horizontal gene transfer include
transformation, conjugation, and transduction
involves the uptake of naked DNA
transformation
the ability of a recipient cell to take up DNA from the environment
competence
by _________ of a new DNA fragment, the recipient has gained some ability it previously lacked
integration
a donor cell transfers DNA directly to the recipient cell
conjugation
the donor cell in conjugation forms a ______________ to make contact with the recipient
conjugation pilus
where is DNA transfer through in conjugation
the bridge
a virus that only infects bacteria
bacteriophage
in transduction, a phage carries a ____________ DNA fragment from donor cell to recipient cell
chromosomal
phage enters bacterial genes to a recipient cell
generalized transduction
phage transfers both bacterial and viral genes to a recipient cell
specialized transduction
what percent of our genome is composed of viral DNA fragments
10%
