Exam 3 Flashcards
Heterochromatin is , whereas euchromatin is .
Highly condensed, less compact
What is the role of DNA ligase in the elongation of the lagging strand during DNA replication?
It joins Okazaki fragments together.
In E. coli, which enzyme catalyzes the elongation of a new strand in the 5’ –> 3’ direction?
DNA polymerase III
Which of the following helps to hold the DNA strands apart while they’re being replicated
Single-stranded DNA binding proteins
In DNA for many species, the amount of adenine equals the amount of thymine, The amount of guanine equals the amount of cytosine. Which scientist is responsible for this discovery
Erwin Chargaff
Which of the following results from Griffith’s experiment is an example of transformation?
Most dies after being injected with a mixture of heat killed S and a living R cells
Antiparallel referring to the strains the make up DNA
The 5’ to 3’ Direction of one strand runs counter to the direction of the other strand
Replication in prokaryotes differs from the replication in eukaryotes for which of the following reasons
Prokaryotic chromosomes have a single origin of replication where is eukaryotic chromosomes have many
In the polymerization of DNA, a phosphodiester bond is formed between phosphate group of the nucleotide being added and of the last nucleotide in the polymer
The 3’ OH
Codons are part of the
mRNA
A single peptide
Helps target a protein to the ER
carries in amino acid to the strand of mRNA
tRNA
In the process of transcription
RNA is synthesized
A particular triplet of bases in the template strand of DNA is a 5’ AGT 3’. The corresponding codon for the mRNA transcribed is
3’ UCA 5’
The first event to take place in translation in eukaryotes is
The small subunit of the Ribosome recognizes and attaches to the cap of the mRNA
are noncoding segments of mRNA and are segments that code for functional products
Introns, exons
Once researchers identified DNA as the subunit of inheritance, they asked how information is transferred from DNA in the nucleus to the site of protein synthesis in the cytoplasm. What is the mechanism of information transfer in eukaryotes
Messenger RNA is transcribed from a single gene and transfers information from the DNA in the nucleus to the cytoplasm, where protein synthesis takes place
To repair a thymine dimer by nucleotide excision repair, in which order do the enzymes act
Endonuclease, DNA polymerase l, DNA ligase
An okazaki fragment has which of the following arrangements?
5’ RNA nucleotides, DNA nucleotides 3’
There are 61 mRNA codons that specify an amino acid, but only 45 tRNAs
The rules for bass pairing Between the third-base of a codon tRNA are flexible
It became apparent to Watson and crick after completion of their model that the DNA molecule could carry a vast amount of hereditary information in which of the following
Sequence of bases
During splicing which molecular component of the spliceosome catalyzes the excision
RNA
Which of the following is a function of a single peptide
To translocate polypeptides ER membrane
Cytosine makes a 42% of the nucleotides in a sample of DNA from an organism. Approximately what percentage of the nucleotides in the sample will be thymine
8%
Which of the following can be determined directly from x-ray diffraction photographs of crystallized DNA
The diameter of the helix
A particular triplet of bases in the coding sequence of DNA is AAA. The anti-codon on the tRNA that binds the mRNA codon is
UUU
The nitrogenous base Adenine is found in all members of which group
ATP, RNA and DNA
Which of the following nucleotide triplets best represents a codon
A triplet in the same reading frame as an upstream AUG
What is the role of DNA ligase in the elongation of the lagging strand during DNA replication
It joins okazaki fragments together
If a cell or unable to produce histone proteins, which of the following would be a likely affect
The cells DNA couldn’t be packed into its nucleus
Transcription in eukaryotes requires which of the following in addition to RNA polymerase
Several transcription factors (TF’s)
In his transformation experiments, what did Griffith observe
Mixing he he killed Photogenic strain of bacteria with a living nonpathogenic strain can convert some of the living cells into pathogenic form
Which is on catalyzes the elongation of a DNA strand In the 5’ –> 3’ direction
DNA Polymerase III
Which of the following would you expect of a eukaryote lacking telomerase
A reduction in chromosome length in gametes
Which of the following helps to hold the DNA strands apart while they are being replicated
Single-stranded binding proteins
Which of the following is a function of a poly-A signal sequence?
It codesfor a sequence in eurkaryotic transripts that signals enzymatic cleavage ~1035 nucleotides away
From your understanding of the cell structure, when the newly made polypeptide is to be secreted from the cell where it has been made, what must occur?
Its signal sequence must lead it to the ER from which it goes to the golgi
At a specific area of a chromosome, the sequence of nucleotides below is present where the chain opens to form a replication fork: 3’CCTAGGCtGCAATCC5’. An RNA primer is formed starting t the t of the template. Primer seuence?
5’ACGUUAGG3’