Chapter 11 & Chapter 12 Test
Terms in this set (105)
What was Frederick Griffith trying to do?
make a vaccine to prevent bacterial pneumonia
What animal did Griffith test on?
What is the R strain?
What is the S strain
What did Alloway discover?
that mice did not cause the transformation of the R strain of DNA
What did Meischer discover?
What happened in Griffith's experience that stumped him?
-boiled the s strain bacteria to kill the pneumonia and mixed it with the r strain bacteria
-the mice died
-there was live s strain bacteria in the bloodstream
Why was there live s strain bacteria in the mice after it had been boiled and mixed with the r strain bacteria?
What did Avery, MacCloed, and McCarthy do?
-examined nucleic acids, sugars, and proteins
-boiled the s strain bacteria and added chemicals to destroy RNA, DNA, sugars, and proteins leaving 1 to examine
What did Avery, MacLoed, and McCarthy discover was the transforming substance?
Who experimented with pneumonia on mice?
Who experimented with RNA, DNA, sugars, and proteins?
Oswald Avery, Colin MacLeod, and Maclyn McCarthy
What is a nucleic acid?
a base + a phosphate group + a sugar
What are the 4 bases?
What are the purins?
Guanine and Adenine
What are the pyrimidines?
Cytosine and Thymine
What did Hershey and Chase study?
-growing a virus in a radioactive environment
What is a bacteriophage?
-contains a protein covering a tiny curl of DNA
-attacks and takes over bacteria and makes moe viruses and bursts
What elements did Hershey and Chase study?
sulfur and phosphorus
What happened with sulfur?
The protein carried instructions for viruses
What happened with phosphorus?
DNA carried instructions for the virus
What did Mirsy discover?
All cells in your body have the same amount of DNA
What is Chargaff's Rule?
-there are equal amounts of adenine and thymine
-there are equal amounts of cytosine and guanine
What did Franklin do for an experiment?
-turned DNA into crystal and sent X-RAYS through it
What did Franklin discover from his experiment?
DNA is a double helix with a constant diameter`
What did Griffith do in his experiments and what happened in each one?
-s strain => died with living s strain
-r strain => alive with living r strain
-r strain and s strain => died with both strains
-boiled s strain => alive with nothing
-boiled r strain => alive with nothing
-boiled s strain and r strain => alive with nothing
-s strain and boiled r strain => died with s strain
-r strain and boiled s strain => died with s strain
What did Chargaff do?
analyzed the amounts of the bases in DNA from a diverse amount of organisms
What did Wilkins and Franklin do?
used x-ray diffraction and recorded how X-rays bounced off DNA molecules
What makes up the backbone of a DNA molecule?
a phosphate group that is bonded with a sugar
What did Virchow discover?
-all cells come from preexisting cells
-all cells contain the same DNA
What are free nucleotides?
previously synthesized nucelotides in the cytoplasm that were imported into the nucleus
What is the enzyme that breaks down the double helix of DNA?
What is the enzyme that synthesizes DNA polymer?
What does DNA polymerase do?
-moves along the separated DNA strand and matching bases with complimentary free nucleotides
-connects free nucleotides with one another to form two new DNA strands
What is semiconservative replication?
the process of DNA replication to produce a daughter double helix
What makes DNA replication almost always error free?
What are the 4 different types of mutations?
What is an insertion mutation?
nucleotide pairs are inserted into the DNA
What is a deletion mutation?
nucleotide pairs are removed from the DNA
What is inversion?
a piece of DNA is cut out of a chromosome, turned around, and reinserted into the gap
What is translocation?
a chunk of DNA is removed from one chromosome and attached to another
How does DNA provide instructions for protein synthesis?
What is messenger RNA (mRNA)?
-carries the code for amino acid sequences of a protein from DNA to ribosomes
-synthesizes proteins specified by the base sequence
What are codons?
groups of 3 bases that specify which amino acid will be incorporated into a protein
What are ribosomes?
structures that carry out translation that are composed of rRNA and many different proteins
What does the small subunit of ribosomescontain?
-has binding sites for mRNA, a start tRNA and proteins that make up the preinitiation complex
-starts protein synthesis
What does the large subunit of ribosomes contain?
has binding sites for 2 tRNA molecules and a catalytic site for joining amino acids
What happens to the subunits during protein synthesis?
they come together and clasp an mRNA molecule between them
What does transfer RNA (tRNA) do?
-delivers the appropriate amino acids to the ribosome for incorporation into a protein
How many tRNAs are synthesized for each amino acid?
How many enzymes recognize tRNA?
What is an anticodon?
a group of 3 bases the protrudes from tRNA
What happens in transcription?
-information in DNA is copied into mRNA, tRNA, and rRNA
-genes are copied into RNA
-a base sequence of mRNA encodes amino acis and the sequence of proteins
Where does transcription occur in eukaryotic cells?
What happens in translocation?
-the mRNA base sequence is decoded
-the rRNA forms the ribosome
-tRNA brings amino acids to the ribosome
-mRNA binds to the ribosome
-base pairing between mRNA and tRNA converts the base sequence of mRNA into the amino acid sequence of proteins
Where does translation occur in eukaryotic cells?
What dud Gamow discover?
3 bases specify a single amino acid
What did Nirenberg and Matthaei do?
-grounded up bacteria and isolated the components needed to synthesize proteins
-added artificial mRNA to control what is translated
What is the start codon?
-codes for amino acid methionine
What do all proteins start with?
What are the stop codons?
How many nucleotide triplets specify the 20 amino acids
What are the 3 steps of transcription?
What are the 3 major parts of genes?
-a prometer region
-a termination signal
What is a prometer?
an untranscribed sequence of DNA located near the beginning of every gene
What are the 2 main parts of a prometer?
-a short sequence of bases that binds to RNA polymerase
-transcription factor binding sites/response elements
What do transcription factors do?
attach to binding sites and enhance or suppress the binding of RNA polymerase to the prometer which will enhance or suppress transcription of the gene and the DNA unwinds
When does transcription stop
when the RNA polymerase reaches the termination signal and detaches from the DNA
What happens in RNA synthesis in prokaryotes?
-transcribes a single, very long mRNA from a series of adjacent genes
-transcription and translation are usually not separated
-the mRNA molecule separates from the DNA and the ribosomes immediately begin translating mRNA into protein
What happens in RNA synthesis in eukaryotes?
-transcription and translation are separate
-genes that encode proteins needed for metabolic pathway are dispersed among several chromosomes
-each gene consists of 2+ segments of DNA with nucleotide sequences that aren't translated into proteins
What are exons?
coding segments that are expressed in the protein
What are introns?
noncoding segments that are withing a gene
What happens in transcription in eukaryotes?
-move finished mRNA through the nuclear envelope to the cytoplasm to bind to the ribosome and prevent cellular enzymes from breaking down the mRNA
What are the possible functions of intron-exon gene structure?
-allows the cell to produce multiple proteins from a single gene by splicing exons together in different ways
-exons can be exchanged among genes to produce more genes that may be harmful or beneficial
What are the 3 steps of translation?
What happens during initiation?
-tRNA and mRNA binds to a ribosome
-finds AUG codon to form pairs with UAC anticodon
large ribosomal subunit attaches to the small subunit with mRNA in between them
What happens during elongation?
-amino acids are added one at a time to the protein chain
-break bond holding methionine to tRNA and form a peptide bond
-1 tRNA is empty and 1 tRNA has 2 amino acids => the empty one is released
What is the preinitiation complex?
the small ribosomal subunit, a methionine tRNA, and several proteins
What happens during termination?
-a stop codon signals the end of translation
-release factors bind to the ribosome when it encounters the stop codon
-the ribosome will release the finished protein chain and the mRNA
-the ribosome dissembles and is ready to be used again
What is substitution?
-a point mutation
-altered amino acid sequence
-the protein may be unaffected or destroyed
What is a neutral mutation?
no detectable change in the function of the encoded protein
What happens in gene regulation in prokaryotes?
organized in operons that are regulated depending on the function
What is an operon?
packages of genes that are close together on one chromosome dependent on their functions and are turned on and off together
What does an operon consist of?
What do regulatory genes do?
controls the timing or rate of transcription
What does an operator do?
governs the access of RNA polymerase to the promoter or the structural genes
What do structural genes do?
encodes related enzymes or other proteins
What are repressor proteins?
regtulatory genes that can bind to the operator site
When can gene regulation occur in eukaryotes?
-cells can control the frequency at which an individual gene is transcribed
-the same gene may be used to produce different mRNAs and protein products
-cells can control the rate at which proteins are degraded
Where was gene regulation studied?
E coli and bacteria
What did Monod and Jacob do?
-examined digested lactose
What operator was studied by Monod and Jacob?
What happens when a promoter is very sticky?
-turned on and off regularly
-genes are needed everyday
What did McClintok do?
-discovered jumping genes
What do jumping genes do?
-flip DNA and cut it
-put it in backward to shut off gene
-put it back in the right way to turn the gene back on
What is the flipase inverting enzyme?
flips the entire DNA sequence
What are transposons?
genes that can go from one place to another on a chromosome or on a whole other chromosome
What are antibodies?
-made in body when exposed to bacteria
-attacks bacteria and foreign invaders
What is a missense mutation
the protein shuts down and won't work because the wrong amino acid is in the wrong place
What are epigenetics?
changes in genes during their lifetime
What can be regulated in the replication of genes?
-the processing of mRNA
What is the Lyon hypothesis?
Only need one X chromosome to survive
What did Messelson and Stahl study?
radioactive DNA in bacterial cells
What dud Beadle and Tutum do?
-one gene for one enzyme hypothesis
What did Garrod study?
alkaptonorea => a missing enzyme that everyone else has