Chapter 10 Flashcards
have characteristics of both living and non-living things
viruses
what are the components of a virus
DNA (or RNA) and protein
used 2 types of pneumococcus bacteria (type s & type r)
griffith
differences between the two types of pneumococcus bacteria
type s- caused diseases in mice
type r- harmless
what happened when griffith mixed dead S with live R
the mice died, living S cells were found in the dead mice
what did griffith’s experiments conclude
something remaining in the dead type S changed the type R into type S
cells change phenotype
transformation
chemically identified griffith’s “transforming factor” as DNA
Avery, MacLeod, and McCarty
used bacteriophages
Hershey and Chase
structure of DNA
2 polynucleotide chains
3 parts of a nucleotide
nitrogenous base, 5-carbon-sugar (deoxyribose), phosphate group
pyrimidines
thymine & cytosine
purines
adenine & guanine
strong bonds between nucleotides
covalent bonds
what parts of nucleotides are bonded covalently
sugar of 1 nucleotide and the phosphate group of the next (sugar-phosphate backbone)
shape of DNA
double helix
discovered DNA’s structure
watson and crick
provided information to the discovery of DNA’s structure through x-ray crystallography
Franklin
complimentary base pairing rules
A bonds with T
C bonds with G
which type of bond holds nitrogenous bases together
hydrogen bonds
semiconservative
each double helix is 1/2 old and 1/2 new
enzyme that breaks hydrogen bonds between base pairs
helicase
enzyme that links nucleotides together and checks for mistakes
DNA polymerase
how does genotype determine phenotype
DNA determines the synthesis of proteins
made connections between DNA and protein using experiments with bread mold; “one gene- one enzyme hypothesis” “one gene-one polypeptide”
Beadle and Tatum
2 steps of protein synthesis
transcription and translation
copying information in genes (DNA) into RNA molecules
Transcription
decoding RNA to make protein
Translation
where does transcription occur
in the nucleus
enzyme that links RNA nucleotides to complementary DNA nucleotides during transcription
RNA polymerase
how many phases are in transcription
3 phases; initiation, elongation, termination
what happens in initiation
1) RNA polymerase attaches to the promoter
2) DNA sequence indicating the beginning of the sequence
what happens in elongation
1) RNA polymerase moves along gene
2) complementary RNA nucleotides bond to DNA and are linked together by RNA polymerase
what happens in termination
1) RNA polymerase reaches terminator and detaches from the gene
2) RNA peels away from DNA
3) DNA zips back up
what are the three types of RNA
1) messenger (mRNA)
2) ribosomal (rRNA)
3) transfer (tRNA)
contains info from DNA; encodes the amino acid sequence to be made
messenger RNA (mRNA)
along w protein, makes up ribosomes
ribosomal RNA (rRNA)
brings correct amino acid to ribosome according to code in mRNA
transfer RNA (tRNA)
single strand of RNA; 80 nucleotides long
tRNA
complementary to mRNA codons
anticodon
initiation in translation
1) mRNA binds to ribosome
2) tRNA with complementary anticodon binds to start codon on mRNA
elongation in translation
1) mRNA moves through ribosome
2) tRNA carrying next aa binds to mRNA
3) aa linked by peptide bonds
4) tRNA detaches and can pick up the same aa for use later in the chain
termination in translation
1) stop codon on mRNA reaches ribosome
2) polypeptide is released from ribosome
2 types of mutations
base substitution or base insertion/deletion
1 nucleotide replaces w another
base substitution
add/ remove 1 or more nucleotides
base insertion/ deletion
which type of mutation causes a bigger change in the polypeptide
changes the reading frame ; stop codon could be inserted too early
creation of mutations
mutagenesis
how does mutagenesis occur
1) spontaneously during DNA replication
2) via mutagens - agents causing mutation (chemicals, radiation) ex UV light
