Exam 4 Flashcards
Remember that in peas, the allele for round seeds (R) is dominant and the allele for wrinkled seeds (r) is recessive. when you cross two plants that each produce round seeds, the resulting seeds are all round. What are the genotype possibilities for the parental plants?
RR and RR,
RR and rr, and
Ra and RR
In hedgehogs, the allele for brown fur (B) is dominant and the allele for white fur is recessive. The allele for short quills (S) is dominant and the allele for long quills (s) is recessive. These two genes are not linked. When you cross one parent with the Genotype BsSS with another parent with the genotype BbSs, what will the Brown and short: brown and long: white and short: white and long phenotype ratio be? what do the genotypes of the parents need to be to give the 9:3:3:1 ratio?(you can use a Punnett square if needed.)
3:0:1:0
BbSs and BbSs
Two genes determine coat color in mice- the A and B genes. the dominant A allele deposits pigment into the skin and fur, while the recessive a causes the mouse to be albino. the dominant B allele produces a brown pigment which the recessive b allele produces a black pigment. A brown male mouse with the genotype AaBa is mated with a female mouse with the genotype AaBb. A) What are the possible genotypes of the gametes from either the father or the mother? B) What will be the brown:black:albino ratio of the progeny?
A) AB, Ab, aB, and ab
B) 9:3:4
One gene (A) is able to modify the effect of the second gene (B). this phenomenon is known as:
Epistasis
Flower color in snapdragons id due to a gene with incomplete dominance. RR plants have red flowers, Rr have pink flowers and rr plants have white flowers. which cross is expected to yield progeny with flower colors in a ratio of 1 red: 1 white?
a. Rr x Rr
b. RR x rr
c. RR x Rr
d. Rr x rr
e. none of the above
E. none of the above
No cross will yield that ratio because of the incomplete dominance.
Hemophilia is a sex-linked recessive trait in humans. if carrier female had a child with a nonaffected male, what would be the expected outcome(s)?
None of the daughters and half of the sons would have hemophilia.
A woman who has blood type A has a daughter who is type O. What is a possible genotype for the father?
Ia Io, Io Io, and Ib Io are all options
The AB blood phenotype is an example of:
Codominance
Mendelian genetics True or False:
In any population, only two alleles can exist for a given gene.
False
The strands that make up DNA are antiparallel. This means that:
While the two strands run next to each other in parallel, the 5’-to-3’ direction of one strand is opposite to the 5’-to-3’ direction of the other strand.
A strand of DNA with the sequence 5’- ATTCCG -3’ would have a complementary strand with the sequence:
5’ CGGAAT -3’
Semiconservative replication of DNA involves:
Each of the original strands acting as a template for a new strand.
True or False:
Primase is needed to initiate DNA replication on both the leading strand and the lagging strand
True
The enzyme that restores that phosphodiester linkage between adjacent fragments in the lagging strand during replication is:
DNA ligase
The enzyme that unwinds the DNA double strands during DNA replication is:
Helicase
The enzyme that adds nucleotides to the growing daughter strand during DNA replication is:
DNA polymerase
During DNA replication, the two strands of DNA ______ re-anneal in the wake of the replication fork. During transcription, the two strands of DNA ______ re-anneal in the wake of the transcription bubble. (DO or DO NOT)
DO NOT/ DO
You run a PCR reaction for six cycles starting with a single DNA double helix. Theoretically, how many copies of your DNA would you now have?
128 copies
The parasite Plasmodium falciparum is the most serious form of the tropical disease: malaria. on a molar basis, the genome of P. falciparum contains only 10% cytosine. what is the % of adenosine in the DNA of P. falciparum?
a. 40%
b. 10%
c. 60%
d. 20%
e. It is not possible to calculate from this number based on this information.
a. 40%
The point at which the DNA strands begin to be separated to initiate DNA synthesis is called the:
Origin of replication
True or false:
The lagging strand is synthesized in short 5’ - 3’ fragments, while the leading is synthesized in one long continuous strand 5’ - 3’ strand.
True
Cells lacking telomerase do not survive for the entire lifetime of an organism because:
The removal of the RNA primer following DNA replication leads to a shortening of the telomeric DNA on the lagging strand, which eventually causes loss of DNA and triggers cell death
Which of the following mutations would probably shorten a protein and definitely cause it to have a new sequence at its C-terminus?
a. A silent mutation
b. A nonsense mutation
c. A frameshift mutation
d. A mutation that prevents removal of an intron during splicing
e. Both C and D
e. both a frameshift and a mutation that prevents removal of an intron during spicing
Chromosomal mutations…
Can result in deletions, duplication, or even inversion of large parts of chromosomes
True or False:
Primase is needed to initiate transcription
False
DNA polymerase synthesizes a new strand of DNA in the ______ direction and travels along the template strand in the ______ direction.
5’ -> 3’ / 3’ ->5’
RNA polymerase synthesizes a new strand of RNA in the ____ direction and travels along the template DNA in the ______ direction. finally, proteins are synthesized when the ribosome travels along the mRNA molecule in the ____ direction while synthesizing a protein _____
5’ -> 3’/ 3’-> 5’/ 5’ -> 3’/ N-terminus -> C-terminus
True or False:
DNA encodes information that is transcribed into RNA, and RNS encodes information that is translated into proteins
True
The point at which RNA polymerase binds and separates DNA strands to initiate RNA synthesis is called the:
Promoter
Transcription continues until:
A terminator sequence is encoded
pre-mRNA splicing: True or False:
It removes exons.
False
Which enzyme catalyzes the attachment of an amino acid to tRNA before translation can proceed?
aminoacyl-tRMA synthetase
Each tRNA has two critical sites that are important for its function in decoding mRNA. these are the:
Amino acid attachment site in the 3’ end of the tRNA and the anticodon loop
What is the fourth step when going from initiation to elongation of translation?
Anticodon of charged tRNA base pairs with its codon on mRNA.
During translation, the amino acid (or peptide) attached to the tRNA at the _____ is added to the N-terminus of the amino acid attached to the tRNA at the ____. this is catalyzed by the_____.
P site/ A site/ large ribosomal subunit
The genetic code is “redundant” or “degenerate”, meaning that more than one ____ often codes for a given _____.
Codon/Amino acid
Translation continues until:
A stop codon is encountered and enters the A site of the ribosome.
What occurs in the E site of the ribosome during translation/
An uncharged tRNA is ejected from this site as the ribosome slides to the next codon.
What anticondon in tRNAhis would pair with the codon 5’ - CAU - 3’ in mRNA
5’-AUG-3’
The PCR reaction mixture does not include:
Helicase
