Midterm 1 Flashcards
If you wanted to directly and easily count the number of chromosomes in the sporophytic generation of an angiosperm, which of the following tissues would you choose?
Actively dividing root tip cells
The components of ribosomes are
coded for by nuclear genes.
In a Genbank entry, the gene sequence is given, by convention:
as DNA 5’ to 3’ .
One of the features of DNA that makes it an ideal genetic material is that it is capable of change. Which of the following terms best describes the “capability for change”?
Mutation
When would you expect to observe a bivalent?
Prophase I of meiosis
In any given diploid individual there are two alleles per locus but in a population of individuals there can be many alleles.
True
A promoter
Is where transcription of a gene by RNA polymerase is initiated.
Looking at a gene sequence, the open reading frame is the:
Consecutive DNA sequence from the start to the stop codon
Adenine and guanine are pyrimidines.
False
Which of the following sequences of events is most correct?
DNA is transcribed to RNA which is translated to protein.
The role of the antipodals is
Not known, according to the material presented in class
Translation of mRNA occurs in the __________ of the plant cell.
Cytoplasm
A diagnostic sequence that can predict the beginning of a gene is ATG.
True
Degeneracy refers to the fact that most amino acids are represented by more than 1 codon.
True
In reciprocal crosses between two homozygous parents with contrasting alleles at multiple loci, the eggs of the F1 will be the genetically the same but the F1 endosperms will be genetically different.
True
In 3n endosperm,
2 genomes trace to the female parent and 1 genome to the male parent
Meiosis starts with a 2n cell and ends with 4 identical n daughter cells.
False
A phosphodiester bond is the linkage between the 3’ carbon of one nucleotide and the 5’ carbon of another nucleotide.
True
In the 8-nucleate embryo sac, which of the following will contribute inherited genetic information to the next generation of seed?
Egg
In both the replication of DNA and the transcription of DNA
Synthesis of new strands proceeds 5’ to 3’, with nucleotides added to the ends of developing strands
The three principal classes of RNA are
informational, functional, and regulatory
___________ mutations result in a stop codon, which prematurely ends translation.
Nonsense
After double fertilization there are at least four independent genetically distinct generations coexisting in the angiosperm seed.
True
In the case of a gene encoding a protein, which of following ribonucleic acids is transcribed from the DNA?
mRNA
After an angiosperm megaspore mother cell that is heterozygous at many loci undergoes meiosis
Each of the four haploid cells is most likely to be genetically different
The number of tRNA genes in a plant genome will most likely be:
One hundred or more
Assuming a diploid plant, which of the following is the best working definition of homologous chromosomes?
A pair of chromosomes of similar structure and function, one of which is inherited from the mother and the other from the father
____________mutations result in a change in amino acid sequence.
Missense
A chromosome after the S phase consists of:
Two identical molecules of DNA, joined at the centromere
In the 8-nucleate embryo sac, which of the following will contribute inherited genetic information to the next generation of seed?
Egg
DNA replication is considered a __________________ process.
Semi-conservative
If a Megaspore Mother Cell is 100% homozygous, after meiosis it will produce four genetically distinct daughter cells.
False
In DNA replication, polymerases catalyze the formation of a phosphodiester bond between the 3’-OH of the deoxyribose of the terminal nucleotide in the developing and the 5’ phosphate of the dNTP precursor
True
A plant has the genome formula 2n = 2x = 36. Which of the following is true?
There will be 18 chromosomes in an unfertilized egg nucleus
Exons are always longer than introns.
False
___________ carry amino acids to the growing polypeptide chains.
tRNAs
The nitrogenous base attaches to the _________carbon of the sugar in a DNA nucleotide.
1’
Transcription and processing of mRNA occurs in the __________ of the plant cell.
Nucleus
During the S phase of both mitosis and meiosis there is
DNA replication
A nucleic acid containing a ribose and uracil is most likely DNA.
False
The template strand is also referred to as the sense or coding strand of DNA.
False
__________ and ___________ are key ribonucleic acids involved in the process of translating a mRNA.
tRNA and rRNA
The ________ is the site of pollen recognition:
stigma
Amino acids make up the __________ structure of proteins.
Primary
Crossing over occurs during _______ phase of Prophase of Meiosis I.
Pachynema
Mutations are more likely to be causal (in terms of change in phenotype) if they are in:
Exons
A megaspore mother cell is expected to be
2n
The -OH group attaches to the __________ carbon of the sugar in a DNA nucleotide.
3’
In angiosperms a sporophytic generation may be diploid or polyploid.
True
During the development of the male gametophyte the first post-meiotic mitosis gives rise to:
vegetative and generative nuclei
In angiosperms polyploidy is a rare occurrence.
False
Choose the incorrect base pairing:
Thymine-Cytosine
Post-transcriptional processing involves each of the following EXCEPT for:
Exon removal
The 8-nucleate embryo sac includes all of the following except:
Pollen
The role of the synergids is to
ttract the sperm to the egg
Two key roles of the centromere are: 1) it is the point of attachment between the sister chromatids at cell division; 2) it is the point of attachment of the spindle fibers during the separation of the sister chromatids.
True
All mutations are deleterious:
False
A chromosome is a DNA molecule complexed with ___________.
Histone proteins
Given the following DNA sense strand – 5’ ATG GCC TGG ACT TCA 3’, what is the corresponding mRNA?
5’ AUG GCC UGG ACU UCA 3’
Mutations that involve insertions and/or deletions of single or multiple nucleotides are referred to as __________.
INDELs
The only useful DNA mutations are those that lead to changes in phenotype.
False
It is possible that a mutation at an exon/intron splice site could lead to a nonsense mutation.
True
DNA codons specify for __________.
Amino acids
If a plant is 2n = 42, how many pairs of sister chromatids do you expect at Metaphase of mitosis?
42
Mitosis can occur in all cells at all times in the life of a cell, while meiosis can only occur in specialized reproductive cells at specific times during the life of a cell.
True
Which of the following statements is FALSE?
Ribosomes are required for transcription
The two sperm in a pollen grain are expected to have the same genetic composition
True
One of the features of DNA that makes it an ideal genetic material is that it is capable of faithful replication. Which of the following best describes its “capability of faithful replication”?
Complementary base pairing and repair machinery
During DNA replication, a new nucleotide is added to the ___________carbon sugar of the previous nucleotide via a phosphodiester bond.
3’
During Meiosis I, the random alignment of chromosomes at the Metaphase plate is the basis for ____________.
Independent Assortment
The pistil consists of the following plant parts:
stigma, style, and ovary
During the development of the female gametophyte the megaspore mother cell undergoes:
A single round of meiosis followed by 3 post-meiotic mitoses
Transfer RNAs (tRNAs)
are very specialized, with each tRNA able to carry a specified amino acid
If you know the primary structure of a protein you can deduce the exact DNA code of the corresponding gene.
False
The total DNA content doubles during the ________ phase of the mitotic cell cycle.
S
Double fertilization in angiosperms results in which of the following:
A 2n embryo and a 3n endosperm
Imagine a 2n=32 cell going through the anaphase of mitosis. If the spindle fibers fail to do their job, what happens to the daughter cells?
One will have 64 chromosomes, the other will have none
The expected monohybrid genotypic ratio in the F2 is 1AA:2Aa:1aa. If you chose one of the F2 Aa individuals and selfed it, you would expect its F3 progeny to segregate in a genotypic ratio of 1AA:2Aa:1aa.
True
When a cross between two plants is written, which of the following is the generally accepted convention?
The female is given first
Which of the following statements makes the most sense, in the context of a diploid plant that is 2n = 2x = 20?
A large number of alleles are possible in a population of the species but only two alleles occur at one time in any given plant
Which of the following best describes a Mendelian genetic analysis in a hermaphroditic plant?
Making a cross and analyzing the patterns of inheritance in the progeny of the cross
You make a cross between two inbred parents that have alternative alleles at many loci. With each generation of selfing after the F1, you expect the percentage of heterozygosity to decrease by
50%
Assume you have two homozygous (diploid) corn plants. The plants differ from each other in having different alleles at approximately half the loci in the corn genome. F1 plants will be heterozygous at approximately how many loci?
15,000
Two good reasons for not saving selfed (or inter-crossed) seed produced by F1 hybrid plants are: (1) the population of F2 plants you grow from the saved seed will be highly variable, and (2) in the case of some varieties, it may be against the law to save and re-plant seed.
True
If you observe a 1:1:1:1 ratio for two qualitative traits in a test-cross population, what might you hypothesize?
Two unlinked genes determine these traits
A test-cross is a
Type of backcross, where the F1 is crossed to the recessive parent
If you study inheritance using only doubled haploids, you can easily determine if an allele is dominant or recessive.
False
A pollen mother cell (PMC) has the genotype VvQQ. The tetrad of microspores resulting from meiosis of the PMC will have which genotypes?
VQ,VQ,vQ,vQ
If a trait is reported to show quantitative inheritance, it will be a perfect candidate for Mendelian analysis.
False
In a diploid species such as Hordeum vulgare, one would expect to see a __________ ratio in a doubled haploid population.
1:1
A classic explanation for quantitative traits is that they are controlled by multiple loci, and alleles at these loci each have small effects.
True
It is useful to include parents in phenotypic frequency distributions (histograms) in order to develop preliminary hypotheses regarding the inheritance of the target trait.
True
