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’
Replication begins at a special site on a bacterial chromosome, called the (blank)
origin of replication.
Bacterial cells can complete DNA replication (blank) than eukaryotes
quicker
Replication in eukaryotes starts at many points of origin and spreads with many replication (blank)—places where the DNA strands are separating and replication is occurring.
bubbles
(BLANK) are the V-shape ends of the replication bubbles; the sites of DNA replication.
Replication forks
A mismatched nucleotide may occur once per 100,000 base pairs, causing a (blank) in replication.
pause
(blank) is the removal of a mismatched nucleotide; DNA repair enzymes perform this function and reduce the error rate to one per billion base pairs.
Proofreading
Sir Archibald Garrod (early 1900s) introduced the phrase (blank)
“inborn errors of metabolism.”
Garrod proposed that inherited defects could be caused by the lack of a (blank)
Knowing that enzymes are proteins, Garrod suggested a link between (blank) and (blank)
particular enzyme; genes and proteins.
George Beadle and Edward Tatum proposed the (blank) based on their study of (blank)
“one gene, one enzyme hypothesis”; red bread mold.
Like DNA, (blank) is a polymer of nucleotides.
RNA (ribonucleic acid)
Unlike DNA, RNA is (blank)-stranded, contains the sugar (blank) and the base (blank) instead of thymine (in addition to cytosine, guanine, and adenine).
single; ribose, uracil
three major classes of RNA
mRNA, tRNA, rRNA
takes a message from DNA in the nucleus to ribosomes in the cytoplasm.
mRNA (messenger RNA)
transfers amino acids to the ribosomes.
Transfer RNA (tRNA)
along with ribosomal proteins, make up ribosomes where polypeptides are synthesized.
Ribosomal RNA (rRNA)
DNA undergoes (blank) to mRNA, which is (blank) to a protein. DNA is a template for (blank) formation during transcription.
transcription; translated; RNA
Transcription is the first step in gene expression; it is the process whereby a (blank) strand serves as a template for the formation of (blank)
DNA; mRNA
During translation, an (blank) transcript directs the sequence of (blank) in a polypeptide.
mRNA; amino acids
The process from DNA to RNA to protein to trait is the (blank) of molecular biology.
central dogma
The (blank) is a triplet code, each (blank) is comprised of three nucleotide bases of DNA
genetic code; codon
(blank) nucleotides based on 3-unit codons allows up to (blank) different amino acids to the specified.
four; 64
Marshall Nirenberg and J. Heinrich Matthei (1961) found that a(n) (blank) that could be used to construct synthetic (blank) in a cell-free system; they showed the codon UUU coded for phenylalanine.
enzyme; RNA
By translating just three nucleotides at a time, Marshall Nirenberg and J. Heinrich Matthe assigned an (blank) to each of the RNA (blank), and discovered important properties of the genetic code.
amino acid; codons
The code is (blank): meaning what? this protects against potentially harmful mutations.
degenerate; most amino acids have more than one codon;
The genetic code is (blank); meaning what?
unambiguous; each triplet codon specifies one and only one amino acid.
The code has (blank) and (blank) signals. How many of each?
start and stop signals: there is one start codon and three stop codons.
The few exceptions to the universality of the genetic code suggest the code dates back to the very first organisms and that all organisms are related (blank). Once the code was established, changes would be disruptive.
evolutionarily
To start the production of mRNA, what does the DNA do?
the DNA double helix unwinds and unzips
Transcription begins when (blank) attaches to a (blank) on DNA.
RNA polymerase; promoter
A (blank) is a region of DNA which defines the start of the gene, the direction of transcription, and the strand to be transcribed.
promoter
an enzyme that speeds formation of RNA from a DNA template
RNA polymerase
Transcription: As RNA polymerase moves along the
template strand of the DNA, complementary RNA (blank) are paired with DNA (blank) of the (blank) strand. The strand of DNA not being transcribed is called the (blank) strand.
nucleotides; nucleotides; coding; noncoding
Transcription: RNA polymerase adds (blank) to the (blank) end of the polymer under construction. Thus, RNA synthesis is in the (blank) direction.
nucleotides; 3’ ; 5’-to-3’
Transcription: The RNA/DNA association is not as stable as the DNA double helix; therefore, only the newest portion of the (blank) molecule associated with (blank) is bound to DNA; the rest dangles off to the side.
RNA; RNA polymerase
Transcription: Elongation of (blank) continues until (blank) comes to a stop sequence.
mRNA; RNA polymerase
Transcription: The stop sequence causes RNA polymerase to stop transcribing (blank) and to release the (blank) transcript.
DNA; mRNA
Transcription: Many RNA polymerase molecules work to produce (blank) from the same (blank) region at the same time.
mRNA; DNA
Transcription: Cells produce thousands of copies of the same (blank) molecule and many copies of the same (blank) in a shorter period of time than if a single copy of (blank) were used to direct protein synthesis.
mRNA; protein; RNA
Transcription: mRNA production: newly formed pre-mRNA transcript is processed before leaving the (blank)
nucleus
Transcription: Pre-mRNA transcript is the immediate product of (blank); it contains (blank) and (blank)
transcription; exons and introns.
Transcription: The ends of the (blank) molecule are altered: a (Blank) is put on the 5’; end and a (blank) is put on the 3’ end.
mRNA; cap; poly-A tail
Transcription: The (blank) is a modified (blank) where a ribosome attaches to begin translation.
cap; guanine (G)
Transcription: The (blank) consists of a 150–200 (blank)nucleotide chain that facilitates transport of mRNA out of the nucleus and inhibits enzymatic degradation of mRNA.
poly-A tail; adenine (A)
Transcription: An (blank) is a protein-coding region of the DNA code in the pre-mRNA transcript eventually expressed in the final polypeptide product.
exon
Transcription: An (blank) is a non-protein coding region of DNA removed by “self-splicing” or spliceosomes before the mRNA leaves the nucleus.
intron
Transcription: (blank) are enzymes made of RNA with the function of removing introns from.
Ribozymes
Transcription: RNA could have served as both (blank) and as the first (blank) in early life forms.
genetic material; enzymes
Transcription: (blank) contain smaller nuclear RNAs (blank). (blank) cut the pre-mRNA transcript and then rejoin adjacent exons. (blank) are capable of identifying the introns to be removed.
Spliceosomes; snRNAs
Transcription: (blank) give a cell the ability to decide which exons will go in a particular mRNA.
Introns
Transcription: mRNA do not have all of the possible (blank) available from a DNA sequence. What is an (blank) in one mRNA could be an (blank) in another mRNA. This process is termed (blank)
exons; exon; intron; alternative mRNA splicing.
Some introns give rise to (blank) which regulate mRNA translation by bonding with mRNA through (blank) and preventing (blank) from occurring.
microRNAs (miRNA); complementary base pairing; translation
(blank) shuffling occurs when introns encourage crossing over during (blank)
Exon; meiosis
(blank) takes place in the cytoplasm of eukaryotic cells. It is the second step by which gene expression leads to protein synthesis.
Translation
In Translation, One language (blank) is translated into another language (blank).
nucleic acids; protein
Transfer RNA (tRNA) molecules transfer (blank) to the (blank)
amino acids; ribosomes
The tRNA is a single-stranded ribonucleic acid that doubles back on itself to create regions where
(blank) are (blank)-bonded to one another.
complementary bases; hydrogen
Translation (tRNA): The (blank) binds to the 3’ end; the opposite end of the molecule contains a(n) (blank) that binds to the (blank) codon in a complementary fashion.
amino acid; anticodon; mRNA
Translation (tRNA): There is at least one (blank) molecule for each of the 20 amino acids found in proteins.
tRNA
Translation (tRNA): There are fewer (blank) than codons because some (blank) pair with more than one codon; if an anticodon contains a (blank) in the third position, it will pair with either an A or G—this is called the (blank)
tRNAs; U; wobble hypothesis
Translation (tRNA): (blank) are amino acid-charging enzymes that recognize which amino acid should join which tRNA molecule, and covalently joins them. This requires ATP.
Aminoacyl-tRNA synthetases
Translation (tRNA): An (blank) forms, which then travels to a ribosome to “transfer” its amino acid during protein synthesis.
amino acid–tRNA complex
Translation (rRNA): Ribosomal RNA (rRNA) is produced from a (blank) template in the (blank) of the nucleus.
Ribosomal RNA (rRNA); nucleolus
Translation (rRNA): The rRNA is packaged with a variety of (blank) into (blank) subunits, one larger than the other.
protein; ribosomal subunits
Translation (rRNA): Subunits move separately through (blank) pores into the cytoplasm where they combine when (blank) begins.
nuclear envelope; translation
Translation (rRNA): Ribosomes can remain in the (blank) or attach to the (blank)
cytoplasm; endoplasmic reticulum
What cell contains more ribosomes? prokaryotic or eukaryotic
eukaryotic
