General Ecology Finals Part 2 Flashcards
When was DNA first noticed and who noticed it?
in 1869; Friedrich Miescher
How was DNA first discovered and what was it called?
Friedrich Miescher isolated it from nuclei of white blood cells; He called it “nuclein”
In 1895, Edmund Wilson first suggested that DNA might be [..]. He observed that [..] and [..] contribute the same number of [….] during reproduction.
hereditary material; sperm and eggs; chromosomes
DNA is a polynucleotide consisting of what four repeating subunits and held together by what bonds?
adenine (A), thymine (T), cytosine (C), and guanine (G), held together by covalent bonds
In 1923, DNA was localized to […] and made a candidate for the […]. However both […] and […] are found in […].
chromosomes; the hereditary material; proteins and RNA; chromosomes
What other candidates are there for the hereditary material besides DNA?
Lipids and carbohydrates
Frederick Griffith identified two strains of Pneumococcus: S, which caused […] in mice, and R which […]. A single gene mutation change can convert an […] strain to an […] strain of the same antigenic type.
fatal pneumonia; did not;
S (smooth); R (rough)
Griffith proposed the transformation factor as the molecule that transformed the […] into […]. He said the transforming factor carried […] but he could not identify the […]
R I I ; S I I I; hereditary information; molecule
Avery, MacLeod, and McCarty used […] and [..] to infect mice. The […] of heat-killed S I I I bacteria was divided into […] and treated to destroy either [..], [..], [..], or [..] and [..] before mixing with live RII bacteria.
heat-killed S I I I bacteria; live R I I bacteria; extract; aliquots; DNA, RNA, proteins, or lipids and polysaccharides
[..] in 1952, showed that D N A is responsible for bacteriophage infection of bacteria cells. What are bacteriophages? Phages such as T2 have a […] that attaches to the host cell and a head that contains [..]
Hershey and Chase; viruses that infect bacteria; protein shell with a tail segment; D N A
Phages must infect [..] to reproduce. How does infection begin?
bacterial hosts; when the phage injects DNA into the bacterial cell and leaves its protein shell on the surface;
The phage DNA replicates in the bacterium and produces [..] that are assembled into […]—these are released by [..]
proteins; progeny phage; the host cell
DNA structure identified by […] and modeled by [..] and [..].
Rosalind Franklin;Watson; Crick
DNA composed of four kinds of [..], A, T, C, and G, joined by […] with [..] that come together to form a [..]
nucleotides; covalent phosphodiester bonds; two polynucleotide chains; double helix
What is a DNA nucleotide composed of?
sugar, one of four nitrogenous bases, and up to three phosphate groups
What is deoxyribose? How many carbons does it have and what are they identified as?
the sugar of DNA nucleotides; it has five carbons, identified as 1′, 2′, 3′, 4′, and 5′
A nucleotide base is attached to what? A hydroxyl group is attached to what? 1-3 phosphates are attached to what?
1′ carbon; 3′ carbon; 5′ carbon
How many rings do pyrimidines and purines have. Which nucleotides are pyrimidines and which are purines?
pyrimidines (thymine and cytosine) - single ring. purines (adenine and guanine) - double ring
Deoxynucleotide monophosphates that are part of a polynucleotide chain have [..] and are called [..] where N refers to what? Deoxynucleotide triphosphates (d N T P s) are not part of a [..].
single phosphates; dNMPs; four bases; polynucleotide chain
Individual nucleotides are assembled into [..] by the enzyme [..]. It catalyzes the formation of a [..] between the […] and the […] of an adjacent one
chains; DNA polymerase; phosphodiester bond; 3′ hydroxyl group of one nucleotide; 5′ phosphate
Each polynucleotide chain has a [..] , consisting of [..] and [..]
sugar-phosphate backbone; alternating sugar; phosphate groups
DNA polymerase catalyzes chain growth in [..].
5 ‘ to 3’ direction
The two polynucleotide chains of a double helix form a [..] that follows two rules: The bases of one strand are [..] to the bases in the [..] The bases pair by [..].
The two strands are [..] with respect to their [..].
stable structure; complementary; corresponding strand; hydrogen bonding; antiparallel; 5′ and 3′ ends
The [..] of D N A is the most common and has a […] of the helix, as does the A-form. [..] D N A is occasionally detected in [..] and is common in [..]. [..] D N A was discovered by [..] and colleagues in 1970 and is commonly found near […].
B-form; right-handed twist; A-form; cells; bacteriophage
Z-form; Robert Wells; transcription start sites
There is a […] to the sugar-phosphate backbone of […], due to its […] twist of the helix
zigzag appearance; Z-form D N A; left-handed
The integrity of the nucleotide sequence of D N A is of [..] importance. The general mechanism of D N A replication is the [..] in all organisms. As organisms [..] and became more [..], some differences did develop in the [..] and […].
paramount; same; diverged; complex; replication proteins; enzymes
Each strand of the […] molecule remains intact during replication. Each parental strand serves as a […] for formation of an […]. Completion of replication results in the formation of […] composed of […]
parental DNA; template; antiparallel, complementary daughter strand. two identical daughter duplexes; one parental and one daughter strand
A consequence of complementary base pairing is that nucleotides on one strand of the duplex can be used to identify nucleotides on the [..]. After the D N A structure was identified, […] competing models of D N A replication emerged
All shared the idea that the original strands of the duplex act as […].
other strand; three; daughter strand synthesis
[…] DNA replication- [..] daughter duplex contains […] parental and […] daughter strand. […] DNA replication- […] daughter duplex contains […] parental strands and the other contains […] daughter strands. […] DNA replication- […] daughter duplex contains […] parental and daughter segments
Semiconservative; each; one; one daughter strand; Conservative; one; both; both; Dispersive; each; interspersed
In 1958, Meselson and Stahl used […] centrifugation to test the models of D N A replication. This method is capable of […] molecules with slightly different molecular weights. They began by growing […] in a medium containing […] for many generations
cesium chloride; separating; E. coli; heavy nitrogen;
Once all the […] in the culture had DNA containing only the heavy nitrogen, they transferred the bacteria to medium containing 14N. After one round of replication, the DNA of an […] was isolated and centrifuged to determine its [..]. The same was done after successive [..]
bacterial cells; aliquot of cells; density;replication cycles.
D N A replication is most often […], proceeding in both directions from a single origin of replication in bacterial chromosomes.[…] have multiple origins of replication
bidirectional; Eukaryotic chromosomes
[…] work showed expansion around the origin of replication, forming a […] , once replication gets under way in bacteria
At each end of the replication bubble is a […] ; replication is complete when the replication forks […].
John Cairn’s; replication bubble; replication fork; meet
Electron micrograph analysis shows multiple […] on eukaryotic chromosomes. […] contain hundreds to thousands of origins of replication
The human genome may contain more than […] origins.
origins of replication; Eukaryotic genomes; 50,000
Replication origins have sequences that attract […]. The origin of replication sequence of E. coli is called […], which contains about […] bp of A-T rich D N A
The origin is subdivided by […] 13-bp sequences followed by […] 9-b p sequences.
replication enzymes; oriC; 245; three; four
Replication origins of bacterial species have […] but not identical sequences. Comparison within and among related species leads to identification of […] the nucleotides found most often at each position of D N A in the […]. The 13-mer and 9-mer sequences of oriC are […] —they play an essential role in replication
similar; consensus sequences; conserved region; conserved
[…] has the most fully characterized origin-of-replication sequences. The multiple origins of replication are called […]. ARS organization and sequence is similar throughout the […]. Replication origins of other […] are less well characterized.
Saccharomyces cerevisiae (yeast); autonomously replicating sequences (ARS); yeast genome; eukaryotes
Replication in E. coli requires that […] locate and bind to oriC consensus sequences; these enzymes are […], […], and […].
replication-initiating enzymes; D n a A, D n a B, D n a C
D n a A first binds the 9-mer sequences, bends the [..] , and breaks […] in the A-T rich 13-mer region. D n a B is a […] that breaks hydrogen bonds to separate the […] and unwind the […]. (DnaC delivers DnaB to the oriC region). The unwound D N A strands are kept from […] by […]
DNA; hydrogen bonds; helicase; strands; helix; reannealing; single-stranded binding protein (S S B)
DNA polymerase […] DNA strands by adding nucleotides to the […] end of a preexisting strand. They cannot initiate DNA strand synthesis on their own […] are needed; these are synthesized by a specialized R N A polymerase called […]. In E. coli, primase joins DnaA, DnaB, and DnaC at [..]
elongates; 3′; RNA; PRIMASE; oriC
In E. coli, daughter D N A strands are synthesized by the […]. The […] is a large protein complex found at each replication fork.
DNA polymerase III (pol III)holoenzyme; REPLISOME
The replisome includes […] different DNA pol III holoenzymes. Replisomes also contain other proteins that hold the two DNA pol III holoenzymes together within the replisome for […] and […] strand DNA synthesis
two; leading; lagging
One copy of pol III synthesizes one daughter strand continuously in the […] direction as fork progression. This is the […] The other copy of pol III elongates the other daughter strand […] , in the […] direction to fork progression, via short segments (Okazaki fragments). This is the […]
same; leading strand; discontinuously; opposing; lagging strand
DNA Polymerase I uses two activities to complete replication: Its 5′-3′ […] removes the RNA primers. Its 5′-3′ polymerase activity adds […] to the 3′ end of the DNA segment preceding the primer. […] seals the gap among the resulting DNA segments.
exonuclease activity; DNA nucleotides; DNA ligase
Each replisome complex carries out replication of the leading and lagging strand […]. DNA polymerases do not have the […] on their own for daughter strand synthesis and progression along the template. To enhance the processivity of polymerases, an […] called the sliding clamp is used
simultaneously; momentum; auxiliary protein complex
The […] can close around the double-stranded D N A during replication. It has a “doughnut hole” of about into which the […] fits. The sliding clamp […] the DNA pol III core enzyme to the template. It is key to the […] level of pol III activity.
sliding clamp; DNA; anchors; high
DNA replication is very […], mainly because most DNA polymerases undertake […] to correct occasional errors. Errors in replication occur once about every […] nucleotides in E. coli.
Proofreading ability of D N A polymerase enzymes is due to a 3′-to-5′ […]
accurate;DNA proofreading; billion; exonuclease activity
Replication errors produce a […] and inability of the mismatched bases to form the appropriate […]. This leads to […] of the 3′ O H into the 3′-to-5′ exonuclease site of the enzyme
Several nucleotides (including the incorrect one) are […] and new nucleotides are […].
DNA mismatch; H bonds; displacement; removed; incorporated
Unwinding of chromosomes during DNA replication will create […], potentially leading to supercoiling of DNA. Enzymes called […] catalyze controlled cleavage and rejoining of D N A to relieve supercoiling
torsional stress; DNA topoisomerases
The leading strand of […] can be replicated to the end. The lagging strand requirement for a primer means that lagging strands cannot be […]. This problem is solved by […] at the ends of linear chromosomes, called […]. These repeats ensure that a portion of a telomere can be safely lost without […] to the organism
linear chromosomes; completely replicated; repetitive sequences; telomeres; consequence
Most human […] experience telomere shortening with successive divisions;
Telomeres are synthesized in […] (and selected other cells) by the […]. The RNA in telomerase is […] to the telomere repeat sequence and acts as a […] for addition of DNA.
somatic cells; germ line cells; ribonucleoprotein telomerase; complementary; template
The template RNA of telomerase allows […] DNA replication to lengthen the telomere sequences. Once telomeres are sufficiently elongated, DNA replication fills out the chromosome […]. Telomere sequences differ along […].
new; ends; species lines
In addition to the repetitive DNA sequence, most eukaryotic telomeres also contain a DNA sequence that forms a […]. The T loop protects the telomeres from […] by binding the protein complex […]. Despite protective measures of telomeres with repetitive sequences and T loops, telomere shortening eventually triggers […]. The […] represents the number of cell cycles of a vertebrate cell before the cell succumbs to apoptosis
knotted fold (T loop); degradation; shelterin; apoptosis; Hayflick limit
Telomere length is important for […] , […], and […]. Some research suggests activating telomerase in somatic cells for […] and […]. However, a majority of […] cells also show activation of telomerase activity, complicating the idea of such action for longevity purposes
chromosome stability, cell longevity, and reproductive success; cell longevity and longer life spans; cancer
