Bio Chapter 14
Primer
Before DNA synthesis begins, a short RNA nucleotide sequence that is paired to a template strand of DNA must be synthesize. What is the name of that RNA nucleotide sequence? Okazaki fragment; Primer; Leading strand; Lagging strand;
telomeres, telomerase
Cancer is characterized by uncontrolled cell division of abnormal cells. Scientists have observed that cancerous cells have considerably shortened _______________ and _____________ is active in these cells.
DNA is linear: eukaryote DNA is circular: prokaryote Condensed around stone proteins: eukaryote Condensed only by DNA supercoiling: prokaryote Arranged in multiple chromosomes: eukaryote Arranged in a single looped structure: prokaryote Has repeating telomere region: eukaryote Does not have telomere region: prokaryote
Classify as prokaryotic DNA structure or eukaryotic DNA structure; DNA is linear: DNA is circular: Condensed around stone proteins; Condensed only by DNA supercoiling: Arranged in multiple chromosomes: Arranged in a single looped structure: Has repeating telomere region: Does not have telomere region:
Telomere
DNA at the tips of chromosomes
Enzymes unwind the DNA, cut out a section on one strand that contains the DNA damage, and resynthesizes the section with the correct DNA sequence;
DNA damage can occur as a result of exposure to chemicals or ultraviolet radiation. What happens during nucleotide excision repair of damaged DNA? Enzymes delete an incorrect DNA base pairing in a DNA strand, remove the incorrect base, and insert the correct base; Enzymes cut out the damaged gene, copy the same gene from the homologous chromosome, and insert the copy; Enzymes unwind the DNA, cut out a section on one strand that contains the DNA damage, and resynthesizes the section with the correct DNA sequence; Enzymes delete an incorrect DNA sequence, pull the gap closed, and join the bases on either side of the gap together;
Okazaki fragments
DNA fragment that is synthesized in short stretched on the lagging strand
conservative
DNA replication is semi _______
proteins, slow
DNA replication is similar in prokaryotes and eukaryotes, but in eukaryotes it includes additional ----------- (for greater regulation) and is _______ (because there is more regulation
A. R strain (nonvirulent): alive B. S strain (virulent): dead C. Heat-treated S strain: Alice D. R strain and heat-treated S strain: dead E. R strain and heat-treated S strain with polysaccharides, lipids, RNA and proteins destroyed: dead F. R strain and heat creates S strain with polysaccharides, lipids, RNA, proteins, and DNA destroyed: alive
Determine whether or not the mice would live or die; A. R strain (nonvirulent): B. S strain (virulent): C. Heat-treated S strain: D. R strain and heat-treated S strain: E. R strain and heat-treated S strain with polysaccharides, lipids, RNA and proteins destroyed: F. R strain and heat creates S strain with polysaccharides, lipids, RNA, proteins, and DNA destroyed:
Smaller DNA fragments move through the gel more quickly than larger fragments move;
How are DNA fragments separated using gel electophoresis? DNA fragments complementary to probes in the gel travel more slowly through the matrix; Negatively charged DNA fragments more through the gel more quickly; Smaller DNA fragments move through the gel more quickly than larger fragments move; Larger DNA fragments bind more strongly to the gel that do smaller DNA fragments;
DNA strands are antiparallel and include a 5' end and a 3' end; DNA bases are always paired using Watson-Crick base pairing; The backbone of DNA is made of a sugar and a phosphate molecule;
Identify the key structural features of a DNA molecule: DNA contains the nucleotide bases adenine, thymine, guanine, cytosine, and uracil; Strong ionic bonds and hydrophobic interaction hold DNA together; The backbone of DNA is made of a sugar and a phosphate molecule; DNA is most often found as a left-handed helix, commonly referred to as Z-DNA; DNA strands are antiparallel and include a 5' end and a 3' end; DNA bases are always paired using Watson-Crick base pairing;
James Watson, Francis Crick and Maurice Wilkins
In 1962, who was awarded the Nobel Prize in Medicine?
Neanderthals and modern humans did not interbreed until after modern humans migrated out of Africa;
Modern humans share a small percentage of their DNA with Neanderthals, with the exception of modern humans of African descent. What conclusion can be drawn from this? Any mating that occurred between modern humans and neanderthals in Africa did not produce viable offspring; Neanderthals and modern humans did not interbreed until after modern humans migrated out of Africa; Eurasian neanderthals migrated back into Africa at some point before modern humans migrated out of Africa; Modern humans evolved in Eurasia after Neanderthals migrated out of Africa and spread through Eurasia
genome
Mutations to DNA repair proteins leads to the accumulation of mutations throughout the _________.
Helicase unwinds the DNA double helix; Single-stranded DNA-binding proteins bind to each template strand; RNA primers are added; DNA polymerase synthesizes DNA; RNA primers are removed; DNA ligase joins DNA fragments together;
Place the steps of DNA replication in order: Helicase unwinds the DNA double helix; RNA primers are added; RNA primers are removed; Single-stranded DNA-binding proteins bind to each template strand; DNA polymerase synthesizes DNA; DNA ligase joins DNA fragments together;
One of the original strands and one new strand;
Since DNA is replicated semiconservatively, what does each new daughter cell receive from the parent cell after replication and mitosis? Two new strands of DNA with the original strands being degraded; One of the original strands and one new strand; A combination of new strands with original strands interspersed; Either both original strands or two new strands;
bacteria
These differences are targeted by some antibiotics like cipro (ciprofloxacin), which targets topoisomerase in _________
lagging strand
Two daughter strands pf DNA are synthesized during DNA replication. Which term describes the new chain of DNA that begins at the replication fork and is synthesized in discontinuous fragments. Primer; lagging strand; Okazaki fragment; leading strand;
They pieced together the available evidence and modeled the structure of DNA;
What contribution did James Watson and Francis Crick make to our understanding of DNA? They produced a clear X-ray diffraction picture of the three dimensional structure of DNA; They found that proteins are not used as the genetic cod, but that DNA is the genetic code; They pieced together the available evidence and modeled the structure of DNA; They determined that adenine and thymine occur in equal amounts in DNA;
Ultraviolet light can cause thymine dimers, potentially creating mutation that could lead to cancer
What generally causes thymine dimers to form in a strand of DNA, and why are thymine dimmers a problem? Ultraviolet light can cause thymine dimers, potentially creating mutation that could lead to cancer; Cancer often causes thymine dimers, which prevent nucleotide excision reaper enzymes from working; Exposure to sunlight can create thymine dimers, which prevents the cell from initiating DNA replication; Smoking often makes thymine dimers form, increasing the chance for mutations that lead to lung cancer;
Meseison and Stahl experiment
What is the experiment with E. coli grown first in heavy nitrogen (15N) then in 14N. DNA grown in 15N (red band) is heavier than DNA grown in 14N (orange band), and sediments to a lower level in cesium chloride solution in an ultracentrifuge. When DNA grown in 15N is switched to media containing 14N, after one round of cell division the DNA sediments halfway between the 15N and 14N levels, indicating that it now contains fifty percent 14N. In subsequent cell divisions, an increasing amount of DNA contains 14N only. This data supports the semi-conservative replication model?
telomerase
What was found to reverse age-related conditions in mice?
The proportion of purines is roughly equal to the proportion of pyrimidines; The proportion of A is roughly equal to the proportion of T; the proportion of C is roughly equal to the proportion of G;
Which conclusions can you draw from this data? The proportion of purines is roughly equal to the proportion of pyrimidines; The proportion of A is roughly equal to the proportion of T; The proportion of A-T base pairs is roughly equal to the proportion of G-C base pairs; the proportion of C is roughly equal to the proportion of G;
DNA polymerase
Which enzyme pairs corresponding nucleotides to a preexisting DNA chain in order to synthesize a new strand of DNA? Helicase; ligase; DNA polymerase; primase;
helicase
Which enzyme separates the two complimentary strand of DNA during DNA replication? ligase; primase; helicase; DNA polymerase;
Enzymes identify the newly synthesized DNA strand, remove a segment surrounding the mismatched nucleotides, and resynthesizes the DNA segment correctly;
Which of the following describes what happens during mismatch repair of DNA? Enzymes identify the newly copied DNA strand, delete the mismatched nucleotide, pull the gap closed and join the nucleotides on either side of the gap together; Enzymes copy the correct DNA sequence from the DNA in another cell, import the DNA sequence, and use the imported DNA sequence to repair the mismatched nucleotides; Enzymes identify the newly synthesized DNA strand, remove a segment surrounding the mismatched nucleotides, and resynthesizes the DNA segment correctly; Enzymes cut out both strands of DNA containing the mismatched sequence, copy the same sequence from the homologous chromosome, and insert the copied sequence;
Hersey and Chase
Who confirmed DNA as a genetic material in 1952?
Frederick Sanger
Who developed the dideoxy chain termination method, in which dye-labeled dideoxynucleotides are used to generate DNA fragments that terminate at different points. The DNA is separated by capillary electrophoresis on the basis of size, and from the order of fragments formed, the DNA sequence can be read. The DNA sequence readout is shown on an electropherogram that is generated by a laser scanner. Won Nobel Prize in Chemestry in 1980
Griffin
Who did GMO transformation in 1928?
Miescher
Who did the first isolation of DNA in the 1860's?
Elizabeth Blackburn
Who discovered how telomerase works
Campbell and Wilmut
Who frist cloned mammals in 1996?
phosphodiester bond
a chemical bond of the kind joining successive sugar molecules in a polynucleotide.
purines
adenine, guanine
glycosidic bond
covalent bond that includes a sugar
pyrimidines
cytosine, thymine, uracil
single strand binding proteins
during replication proteins that binds to the single-stranded DNA; this helps in keeping the two strands of DNA apart so that they may serve as templates
helices
during replication this enzyme helps to open u the DNA helix by breaking the hydrogen bonds
lagging strand
during replication, the strand that is replicated in short fragments and away from the replication fork
DNA polymerase
enzyme that can only add new nucleotides to a 3' OH
ligase
enzyme that catalyzes the formation of a phosphodiester linkage between the 3' OH and 5' phosphate ends of the DNA
Topoisomerase
enzyme that causes underwinding or overwinding of DNA when DNA replication is taking place
Telomerase
enzyme that contains a catalytic part and an inbuilt RNA template; it functions to maintain telomeres at chromosome ends
primase
enzyme that synthesizes the RNA primer; is needed for DNA pol to start synthesis of a new DNA strand
Proofreading
function of DNA pol in which it reads the newly added base before adding the next one
Xeroderma pigmentosum
is a condition in which thymine dimerization from exposure to UV is not repaired. Exposure to sunlight results in skin sessions
leading strand; lagging strand; Okazaki fragment; RNA primer
label the parts from top to bottom, left to right: Okazaki fragment; leading strand; lagging strand; RNA primer;
point mutation
mutation that affects a single base
silent mutation
mutation that is not expressed
induced mutation
mutation that results from exposure to chemicals or environmental agents
spontaneous mutation
mutation that takes place in the cells as a result of chemical reactions taking place naturally without exposure to any external agent
chromosomes; tight helical fiber; nucleosome; histone protein; DNA double helix
order the following from smallest to largest. What builds on what? histone protein; nucleosome; tight helical fiber; chromsomes; DNA double helix;
sliding clamp
ring-shaped protein that holds the DNA pol on the DNA strand
primer
short stretch of nucleotides that is required to initiate replication; in the case of replication, the primer has RNA nucleotides
electrophoresis
technique used to separate DNA fragments according to size
replication fork
the Y-shaped structure formed during the initiation of replication
transformation
the process in which external DNA is taken up by a cell
leading strand
the strand that is synthesized continuously in the 5' to 3' direction that is synthesized in the direction of the replication fork
nucleotide excision repair
type of DNA repair mechanism in which the wrong base, along with a few nucleotides upstream or downstream, are removed
mismatch repair
type of repair mechanism in which mismatched bases are removed after replication
mutation
variation in the nucleotide sequence of a genome
the DNA located at the ends of eukaryotic DNA molecules;
what are telomeres? enzymes that add new nucleotides to template DNA strand during replication; section sof repetitive DNA sequences located anywhere within a eukaryotic DNA strand; The regions of sister chromatids were the sister chromatids are bound together; the DNA located at the ends of eukaryotic DNA molecules;
transversion substitution
when a purine is replaced by a pyrimidine or a pyrimidine is replaced by a purine
transition substitution
when a purine is replaced with a purine or a pyrimidine is replaced with another pyrimidine
