Chapter 12 (Test 3) Flashcards
Early researchers knew that the genetic material must be able to (blank) information used to control the (blank, blank, blank)
store; development, structure, and metabolic activities of
cells
Early researchers knew that the genetic material must be (blank) so it can be (blank) accurately during cell division and be transmitted from generation to generation;
stable; replicated
Early researchers knew that the genetic material must be able to undergo (blank) providing the (blank) required for evolution.
mutations; genetic variability
Bacteriologist (blank) (1931) experimented with Streptococcus pneumoniae (a pneumococcus that causes pneumonia in mammals).
Frederick Griffith
Mice were injected with two strains of (blank): an encapsulated (S) strain and a non-encapsulated (R) strain.
pneumococcus
The (blank) strain is virulent (the mice died); it has a mucous capsule and forms “shiny” colonies.
The (blank) strain is not virulent (the mice lived); it has no capsule and forms “dull” colonies.
S; R
In an effort to determine if the (blank) alone was responsible for the virulence of the S strain, he injected mice with heat-killed S strain bacteria; the mice lived.
capsule
Finally, he injected mice with a mixture of heat-killed (blank) strain and live (blank) strain bacteria.
S; R
The mice died; living (blank) strain pneumococcus was recovered from their bodies.
Griffith concluded that some substance necessary for synthesis of the (blank)—and therefore for virulence—must pass from dead (blank) strain bacteria to living (blank) strain bacteria so the R strain were transformed.
This change in (blank) of the R strain must be due to a change in the bacterial (blank), suggesting that the transforming substance passed from S strain to R strain.
S; capsule; S; R; phenotype; genotype
Oswald Avery et al. (1944) reported that the transforming substance was (blank)
DNA
In the early twentieth century, it was shown that nucleic acids contain four types of (blank)
nucleotides
DNA is composed of repeating units, each of which always had just one of each of four different nucleotides:
a nitrogenous base, a phosphate, and a pentose
Purified DNA is capable of bringing about the (blank)
transformation
DNA from S strain pneumococcus causes R strain bacteria to be (blank)
transformed;
(blank) of the transforming substance with an enzyme that digests DNA (DNase) prevents transformation.
Digestion
The molecular weight of the transforming substance is great enough for some (blank)
genetic variability
Enzymes that (blank) proteins cannot prevent transformation, nor can enzymes that digest (blank)
degrade; RNA (RNase).
Avery’s experimental results demonstrated DNA is (blank) and DNA controls (blank) of a cell.
genetic material; biosynthetic properties
In order to illustrate that transferring genes was possible from one organism to another, scientists used a green fluorescent (blank) from jellyfish and transferred it to other organisms. The result was that these organisms
protein; glowed in the dark
Mammalian genes have the ability to function in other species:
bacteria, invertebrates, plants.
(blank) (1940s) analyzed the base content of DNA.
Erwin Chargaff
DNA contained four different nucleotides:
Two with (blank) bases, adenine (A) and guanine (G); a type of nitrogen-containing base having a (blank) structure.
Two with (blank) bases, thymine (T) and cytosine (C); a type of nitrogen-containing base having a (blank) structure.
Results:
purine; double-ring; pyrimidine; single-ring
DNA does have the variability necessary for the genetic material.
For a species, DNA has the (blank) required of genetic material.
This is given in Chargaff’s rules:
The amount of A, T, G, and C in DNA varies from species to species.
In each species, the amount of (blank) and the amount of (blank)
constancy; A = T; G = C
(blank) produced X-ray diffraction photographs.
His/her work provided evidence that DNA had the following features:
Rosalind Franklin; DNA is a helix & Some portion of the helix is repeated.
American (blank) joined with (blank) in England to work on the structure of DNA.
They received the (blank) in 1962 for their model of DNA.
James Watson; Francis H. C. Crick; Nobel Prize
Using information generated by Chargaff and Franklin, Watson and Crick constructed a model of DNA as a (blank) with (blank) groups on the outside, and (blank) on the inside. Their model was consistent with both (blank)'s rules and Franklin’s (blank) studies.
double helix; sugar-phosphate; paired bases; Chargaff; X-ray diffraction
(blank) is the process of copying a DNA molecule.
DNA replication
Replication is (blank), with each strand of the original double helix (parental molecule) serving as a (blank) (mold or model) for a new strand in a daughter molecule.
semiconservative; template
DNA replication contains what processes?
unwinding, Complementary base pairing, Joining
old strands of the parent DNA molecule are unwound as weak hydrogen bonds between the paired bases are “unzipped” and broken by the enzyme helicase. Process?
unwinding
free nucleotides present in the nucleus bind with complementary bases on unzipped portions of the two strands of DNA; this process is catalyzed by (blank) Process?
Complementary base pairing; DNA polymerase
complementary nucleotides bond to each other to form new strands; each daughter DNA molecule contains an old strand and a new strand; this process is also catalyzed by (blank) Process?
Joining; DNA polymerase
For complementary base pairing to occur, the DNA strands need to be (blank)
antiparallel
One strand of DNA is (blank) at the top and the other strand is (blank) at the top of the strand.
5’
3’
During replication the (blank) can only join to the free 3’ end of the previous (blank)
DNA polymerase; nucleotide
DNA polymerase cannot start the synthesis of a DNA chain, so an (blank) lays out an (blank) that is complementary to the replicated strand. Now the (blank) can join the DNA nucleotides to the (blank) end of the new strand.
RNA polymerase; RNA primer; DNA polymerase; 3’
The (blank) unwinds the DNA and one strand (called the (blank)) can be copied in the direction of the (blank) The other strand of DNA is copied in the direction (blank) from the fork, and replication begins again.
This new lagging strand is discontinuous and each segment is called an (blank), after the
scientist who discovered them.
helicase enzyme; leading new strand; replication fork; away
Okazaki fragment
Replication is only complete when (blank) are removed.
RNA primers During replication
During replication, DNA molecules get
smaller
The end of eukaryotic DNA molecules have nucleotide sequences called (blank)
telomeres.
Telomeres don’t code for proteins. They are repeats of (blank)
short nucleotide sequences
Bacteria have a (blank) of DNA that must replicate before the cell divides.
single loop
Replication in prokaryotes may be (blank) from one point of origin or in only one direction.
bidirectional
Replication only proceeds in one direction, from (blank)
5’ to 3’