Chapter 7 (from quizlet) Flashcards
what did the experiment by Fred Griffith in 1928 with the R and S strains of Streptococcus pneumoniae demonstrate?
Genetic material from one strain could be transferred to another strain
What did the experiment by Avery, MacLeod, and McCarty in 1944 with the R and S strains of Streptococcus pneumoniae demonstrate?
DNA was the genetic material in cells
The Hershey and Chase experiment was able to conclusively demonstrate the DNA (not protein) was the genetic material. They were able to distinguish DNA from protein since labeled___incorporated into DNA while_____ incorporated into proteins.
phosphorous; sulfur
The Watson and Crick model showed that in the DNA molecule..
purines paired with pyrimidines and the strands align anti-parallel to one another
The Watson-Crick model of DNA shows that the base adenine pairs with what?
thymine while cytosine pairs with guanine
What is the main difference between Bacteria and Archae chromosomal DNA when compared to Eukarya chromosomal DNA?
Bacteria and Archaea are cicrular while Eukarya is linear
Replication of the bacterial chromosome begins at how many locations?
one
Replication termination in E. Coli involves which 2 proteins?
Tus protein and topoisomerase II.
What is the term for a special sequence at the end of the chromosome in eukaryal cells?
a telemore
A gene can best be described as a segment of DNA that…
is transcribed as well as the associated regulatory regions
What are micro RNAs?
small regulatory, RNAs
For the initiation of transcription in bacteria, RNA polymerase binds to what region on the gene?
promoter
What is the sigma factor of the RNA polymerase holoenzyme responsible for?
recognition of the promoter region
Most bacterial promoters consist of what two regions?
pribnow (-10) and -35 region
Transcription termination in eukaryal cells is more complex than in bacterial cells as the RNA molecule undergoes further processing before becoming a functional mRna; describe this process
capping the 5’ end with 7-methyl guanosine, adding apoly-A sequence at the 3’ end and removing internal sequences called introns
What is a codon?
3 bases on the mRNA that is read by the ribosome in the 5’ to 3’ direction
Initiation of translation in bacteria starts with the binding of the 30S ribosomal subunit to the mRNA molecule. The ribosomal binding site nearer the ___end of the mRNA molecule and is called the ___
5’; Shine-Dalgarno sequence
The mRNA of bacterial cells is often polycistronic. What is polycistronic?
It contains the code for multiple peptides
- coding for more than one protein
What would a signal peptide be used for?
to move protein to the outside of the cell
What term is used for a point mutation that results in a change in the amino acid specificity of the codon?
missense
What is the point mutation that results in changing a codon from an amino acid codon to a stop codon?
nonsense
What results from a deletion of base pairs such that the amino acid sequence is disrupted from the point downward?
frameshift mutation
What does Rho-independent termination of transcription in bacteria involve?
the formation of a hairpin loop followed by a poly U sequence
Messenger RNA (mRNA) can be best described as a molecule that contains the code for a:
polypeptide
What best differentiates DNA and RNA?
RNA is single-stranded and DNA is double stranded, RNA contains ribose and DNA contains deoxyribose, RNA contains the base uracil in place of thymine, which is in DNA
What are the main enzymes responsible for replication of DNA in eukaryal cells?
DNA pol ε and DNA pol δ
What is true regarding replication of the bacterial chromosome?
replication occurs in a bidirectional manner from the origin of replication, the primase adds a short RNA primer to serve as a starting point for the DNA polymerase to add to new bases, DNA replication is a semi-conservative process where one strand serves as a template for the synthesis of a complementary strand, the incoming nucleotide triphosphate is covalently attached to the free 3’ hydroxyl
