BIOL 3000 Final Exam- Boyer
In Shorthorn cattle, the allele for red coat is co-dominant with the allele for white coat so that heterozygotes have both colors (this phenotype is known as "roan"). What phenotypic ratio would you expect among the offspring of the following cross: Roan x Roan
1 red : 2 roan : 1 white
A man with type AB blood is married to a woman with type A blood. No other information about the couple is known to you. What are the possible blood types of their children?
A, B, or AB
In Mendel's peas, the trait from the round allele (R) is dominant over the trait from the wrinkled allele (r). A plant with round peas was crossed to a plant with wrinkled peas and all of the resulting plants had round peas. What are the likely genotypes of the parents in this cross? Which of Mendel's Big 6 crosses does this match to?
AA x aa, Parental
How are sex limited traits similar to sex influenced traits?
Both are autosomal because their genes are on not on the sex chromosomes, even though they are influenced by sex-based biological differences
In sweet peas, the genes for flower color and pollen grain shape are encoded by two genes C and S. C codes for purple flowers and S codes for long grains. A pure-breeding purple flowering plant with round pollen grains is crossed to a pure-breeding white flowering plant with long pollen grains. What is the genotype of the pure-breeding purple flowering plant with round pollen? What is the genotype of the pure-breeding white flowering plant with long pollen? The resulting F1 offspring are all purple flowering plants with long pollen grains. Based on the genotypes of the parental plants, what allele combinations would these F1 dihybrids have to all have?
CCss, ccSS, Cs | cS
A gene has acquired a mutation in which the protein product has 50 additional amino acids at the end. Which region of the gene was likely mutated?
Stop codon
Amino acids are translated from mRNA codons and each codon is made up of three nucleotide bases. How might an extra single base INSERTION into the second codon of a coding sequence of a gene affect the amino acid sequence of the protein encoded by the gene?
The entire amino acid sequence would shift and be changed.
Some studies have reported that female T. californicus that produce larger first clutches with more offspring also tend to die earlier. Let's assume this same gene as described in the last question causes this benefit early in life and disadvantage later in life. This would be an example of ______________________.
antagonistic pleiotropy
The is/are the region(s) joining two sister chromatids, whereas the is/are the protein(s) associated with the centromeric DNA sequences
centromere, kineticore
Mendel performed numerous controlled genetic crosses to obtain strains that consistently produced a single phenotype without variation. These strains that consistently produce the same phenotype are called _______________.
pure-breeding
Transposons are made of __________
segments of DNA
Why do we say that genes that show incomplete dominance have a dosage effect, but genes that show codominance do not? (C) The amount of one gene product keeps the dosage of the other gene product in check in codominance (B) In codominance, the amount of one allele's product does not influence the amount of the other alleles product. Both products are expressed independently. (A) The amount of gene product from the dominant allele in incomplete dominance is what drives the blending of phenotypes (C) and (D) (A) and (B) (D) The amount of product expressed in incomplete dominance does not influence the phenotype seen
(A) and (B)
The following figure plots change in DNA quantity in a somatic cell during its life cycle. Choose the option that matches the letters to the correct stages of cell division.
(A) Before S phase, (B) G2, (C) After cytokinesis
The following figure plots change in DNA quantity in a single germ cell throughout Meiosis. Choose the option that matches the letters to the correct stages of cell division.
(A) G1, (B) G2, (C) after Meiosis I, (D) after Meiosis 2
In eukaryotes, where can transcriptional regulators bind to DNA relative to the gene they are regulating? -Downstream -Upstream -Only two answers are correct -All answers are correct -Within the gene
-All answers are correct
Which of the following is an example of true deductive reasoning?
All life consumes energy. Cats are alive. Therefore, cats consume energy.
Why do we have to run PCR on the DNA we obtain from a purification process in DNA Barcoding? -All answers listed are correct -There are numerous DNA fragments that we do not want to sequence that may interfere with reactions of the barcode sequence -We need to amplify the specific barcode fragment of DNA that we want to sequence -The amount of DNA is too little to DIRECTLY sequence
-All answers listed are correct
Which of the following is a defined difference between the nuclear and mitochondrial genome? -All of the possible answers are true statements -There are much fewer genes in the mitochondrial genome than in the nuclear genome. -The mitochondrial genome has a different genetic code (in other words, contains different genes). -The mitochondrial genome is circular while the nuclear genome is linear.
-All of the possible answers are true statements
How did scientists create this karyogram (based on what you learned about creating karyograms in our module and videos)? Mark all that are true. -Cells were collected in metaphase (when DNA is compact in dense chromosomes) -Cells were collected in interphase (when DNA is compact in dense chromosomes) -Chromosomes were stained with special dyes to create visible banding patterns -Chromosomes were carefully placed with their homolog (using forceps) for imaging -Using computer software after imaging, chromosomes were ordered in homologous pairs based on the banding pattern -Lastly, chromosomes were ordered largest to smallest (with the sex chromosomes last)
-Cells were collected in metaphase (when DNA is compact in dense chromosomes) -Chromosomes were stained with special dyes to create visible banding patterns -Using computer software after imaging, chromosomes were ordered in homologous pairs based on the banding pattern -Lastly, chromosomes were ordered largest to smallest (with the sex chromosomes last)
In a weird species of worm(?), the presence of hair on the head is controlled by a keratinase enzyme. This enzyme is controlled by two genes, H and N. For each genotype possibility for these two genes, the enzyme pathway and resulting phenotype is shown below. Answer the following questions about this genetic system. The interaction between the N and H genes represents what type of epistasis? Based on the pathway shown, what do the H and N genes likely each do to influence this phenotype? Why does the worm still not have any hair even when Protein N is not expressed (as shown in the second row of the picture)?
-Dominant suppression -The H gene codes for a protein required to make keratinase. The N gene codes for a protein that destroys or inhibits the protein made by gene H. -Even though the N gene is not producing the inhibitory protein N, the H gene is also not making any of the required protein H need to make keratinase
We talked quite a bit about the importance of Mendel's experiment with pea plants in Module 4 and on Packback. You all identified many important and key features of Mendel's experiment that allowed us to finally understand the basics of inheritance and the relationship between dominant and recessive alleles. What features of his experimental design allowed us to learn these important concepts? (Select all that correctly apply). -He chose to experiment with 7 traits that are discrete (one variety or another with no in-between) instead of continuous -He applied math to his experiment, confirming his results with quantitative analyses instead of just qualitative -He allowed plants to pollinate randomly and self-fertilize to understand complex forms of inheritance -He used pea plants, which can be pollinated by hand to avoid cross contamination -He chose to experiment with complex traits that were coded for by multiple separate genes -He created pure-bred or true-breeding strains of pea plants as a control -His main experiment used a monohybrid cross between plants that only differed at a single gene for one trait at a time
-He chose to experiment with 7 traits that are discrete (one variety or another with no in-between) instead of continuous -He applied math to his experiment, confirming his results with quantitative analyses instead of just qualitative -He used pea plants, which can be pollinated by hand to avoid cross contamination -He created pure-bred or true-breeding strains of pea plants as a control -His main experiment used a monohybrid cross between plants that only differed at a single gene for one trait at a time
Mark all the correct options regarding mitochondrial and nuclear DNA (there is more than one correct answer): -Mitochondrial DNA encodes for two rRNAs, 22 tRNAs, and 13 proteins subunits, all of which are involved in the electron transport system -The mitochondrial genome is larger than the nuclear genome (but just by a little bit) - Mitochondrial DNA has different genes than Nuclear DNA - Mitochondrial DNA is circular; Nuclear DNA is linear - Nuclear DNA is circular; Mitochondrial DNA is linear - The nuclear genome is larger than the mitochondrial genome (MUCH larger) - Human mitochondrial DNA only contains between 16,000 and 17,000 base pairs
-Mitochondrial DNA encodes for two rRNAs, 22 tRNAs, and 13 proteins subunits, all of which are involved in the electron transport system -Mitochondrial DNA has different genes than Nuclear DNA - Mitochondrial DNA is circular; Nuclear DNA is linear - The nuclear genome is larger than the mitochondrial genome (MUCH larger) - Human mitochondrial DNA only contains between 16,000 and 17,000 base pairs
Which of the following statements about protein motifs and protein domains are correct? -Protein motifs are smaller regions of protein structure or amino acid sequences that cannot exist functionally or structurally on their own -Protein domains are larger, functional subunits of protein complexes that retain their function and structure on their own -Protein motifs help relate primary structure to secondary structure -Protein domains relate to tertiary structure -Protein domains help relate primary structure to secondary structure -Protein motifs relate to tertiary structure -Protein motifs can retain their structure, even when removed from a larger host protein complex
-Protein motifs are smaller regions of protein structure or amino acid sequences that cannot exist functionally or structurally on their own -Protein domains are larger, functional subunits of protein complexes that retain their function and structure on their own -Protein motifs help relate primary structure to secondary structure -Protein domains relate to tertiary structure
Which of the following factors are unique to meiosis and responsible for genetic variation? -Change from diploid to haploid -Random assortment -Synapsis -Change from haploid to diploid -Fusion -Crossing over -Fission
-Random assortment -Crossing over
Select all the desired qualities for a gene sequence to act as a barcode. -The barcode sequence does not need to be universal; it can be found in some but not all organisms -The barcode sequence needs to be flanked by sequences that are not very different among species, so the barcode stands out as being variable -The barcode sequence needs to very similar between species and very different between individuals within a species -The barcode sequence needs to be conserved or universally found in all organisms -The barcode sequence needs to have very slow rates of neutral change and mutation -The barcode sequence needs to be more similar within a species and more different between separate species -The barcode sequence needs to be short enough to be cheap to sequence and long enough to provide differentiating power -The barcode sequence needs to have higher mutation rates and neutral change than most other genes
-The barcode sequence needs to be flanked by sequences that are not very different among species, so the barcode stands out as being variable -The barcode sequence needs to be conserved or universally found in all organisms -The barcode sequence needs to be more similar within a species and more different between separate species -The barcode sequence needs to be short enough to be cheap to sequence and long enough to provide differentiating power -The barcode sequence needs to have higher mutation rates and neutral change than most other genes
Select all true statements about the cell cycle and mitosis. -Mitosis results in new cells with only half the number of chromosomes as in the parent cell -The cell spends most of its time in interphase undergoing growth and synthesis -Mitosis is the period the cell cycle that involves active cell division -Through mitosis, one parent cell yields two identical daughter cells
-The cell spends most of its time in interphase undergoing growth and synthesis -Mitosis is the period the cell cycle that involves active cell division -Through mitosis, one parent cell yields two identical daughter cells
Traditional Sanger Sequencing and Next-generation sequencing by Illumina and PacBio share some similarities in that they involve creating fragments or clusters of DNA and using fluorescent tags that give off different colors. What does the length of the fragments or size of the clusters of DNA tell us? What does the color of the fluorescent tag tell us?
-The position in the DNA sequence of a given nucleotide -The identity of the nucleotide in a given position
Mark the options that are correct regarding differences/similarities between Meiosis and Mitosis -The process of Metaphase in Mitosis and Meiosis II is essentially the same -Typically Prophase in Mitosis and Meiosis involves crossing over -The process of Metaphase in Mitosis and Meiosis I is essentially the same -In both Mitosis and Meiosis, the terminal cells have the same ploidy as the intial cells (i.e., both processes preserve ploidy) -Mitosis typically results in two cells with the same genetic material; Meiosis typically results in gametes that are variable -Mitosis ends with two cells. Meiosis ends with four cells
-The process of Metaphase in Mitosis and Meiosis II is essentially the same -Mitosis typically results in two cells with the same genetic material; Meiosis typically results in gametes that are variable -Mitosis ends with two cells. Meiosis ends with four cells
Select all the correct statements about the two types of transposable elements. -Type 1 transposons require a reverse transcriptase to insert themselves into DNA -Type 2 transposons do not require a reverse transcriptase to insert themselves into DNA -Type 1 transposons use RNA intermediates to move around in the genome -Type 1 transposons move through a copy and paste mechanism -Type 2 transposons move through a cut and paste mechanism -The only active type of transposon in the human genome is a type 1 transposon -Type 2 transposons use RNA intermediates to move around in the genome -The only active type of transposon in the human genome is type 2 transposon
-Type 1 transposons require a reverse transcriptase to insert themselves into DNA -Type 2 transposons do not require a reverse transcriptase to insert themselves into DNA -Type 1 transposons use RNA intermediates to move around in the genome -Type 1 transposons move through a copy and paste mechanism -Type 2 transposons move through a cut and paste mechanism -The only active type of transposon in the human genome is a type 1 transposon
Below is a simple pedigree tracking a single trait that is rare in population. What modes of inheritance (MOIs) are possible for a trait with this pattern of pedigree? (Select ALL that apply) -Autosomal dominant -X-linked recessive -Autosomal recessive -X-linked dominant -Impossible to tell
-X-linked recessive -Autosomal recessive
How many molecules of DNA make up a single chromosome?
1
In some chickens, F is the trait for frizzled feathers and S is the trait for straight feathers. These alleles show incomplete dominance when they are inherited together. The result is a "slightly frizzled" chicken. What would be the GENOTYPIC result of a cross between a frizzled feather rooster and a slightly frizzled feather hen?
1 FF : 1 FS
One of the chromosomes shown in the karyograms (both of them) contains an inversion compared to its homologous chromosome. Can you identify which chromosome? What type of inversion is this?
1, Pericentric
Match the event to the number to create the correct sequence of events for Meiosis I:
1- DNA condenses 2- Synapses form between homologous chromosomes 3- DNA of non-sister chromatid is exchanged between homologous chromosomes 4- Pairs of homologous chromosomes align on metaphase plate 5- Homologous chromosomes are separated from one another
Match the event to the number to create the correct sequence of events where 1 = earliest and 11 = most recent
1- Darwin published his hypothesis of natural selection 2- Mendel published his hypothesis of discrete inheritance 3- Wilhelm Johanssen coins the term "gene". 4- Thomas Hunt Morgan and his lab discover chromosomes carry genes, and some genes are inherited together (linked) 5- Griffith suggests DNA is the molecule of inheritance 6- Franklin, Wilkins, and Gosling discovers the helical structure of DNA using x-ray diffraction 7- Hershey & Chase experimentally confirm that genes are made of DNA 8- Meselson & Stahl discover the semiconservative mechanism of DNA replication 9- Nirenberg describes the nucleic acid alphabet of DNA 10- Sanger develops the method for DNA sequencing 11- Mullis describes the method for PCR
Match the order of DNA packaging in eukaryotes from least (1) to most (4) compact.
1- Nucleosome 2- 30 nm fiber (solenoid) 3- 300 nm fiber (looped chromatin) 4- chromatid
Nucleosomes are comprised of how many molecules of histones?
8
In some chickens, the gene for feather color is controlled by codominance. The allele for black is B and the allele for white is W. The heterozygous phenotype is known as erminette (black and white spotted). Using the information provided above, if you cross a black chicken with a white chicken, what is the probability they will have erminette chicks as offspring?
100%
Let's say we have an X-linked dominant trait (denoted XT). If we make a cross between a male with the trait (XTY) and female without the trait (XX), what is the probability that a female offspring would have the trait?
100%
According to the table of chromosome numbers in Module 4: Mendel and Meiosis, garden peas have 14 chromosomes in their diploid somatic cells and 7 chromosomes in their haploid gametes. How many different possible combinations of chromosomes can be assorted into a single pea gamete? How many possible combinations of zygotes would that enable?
128, 16384
Professor Oak is starting a new breeding program and has asked you as a geneticist to determine how many unique Pikachu are possible from one mating pair. You know that there are a total of 40 chromosomes in a somatic Pikachu cell, and that they are diploid organisms (one maternal, one paternal, just like humans). How many possible unique gametes could come from a single Pikachu? If these two pikachu mate, how many unique combinations of chromosomes could their baby pichu have?
1.0x10^6, 1.1x10^12
Red-green color blindness is an X-linked recessive disorder. An XX female with normal vision whose father was colorblind has children with an XY male with normal color vision. What is the probability that their first child will have the colorblind phenotype?
1/4
What GENOTYPIC ratio would you expect to observe among the offspring of a heterozygous monohybrid cross? What PHENOTYPIC ratio would you expect to see in the offspring from this exact same cross?
1:2:1, 3:1
You can also use the product rule to quickly calculate the inheritance of individual alleles of a single gene. In Chesapeake Bay Retriever's, Brown Eyes (B) are DOMINANT to Blue Eyes (b). If a homozygous recessive dog and heterozygous dog mate (bb x Bb), what is the correct product rule equation that demonstrates how you could calculate the likelihood of getting a blue eyed (bb) offspring?
2/2 x 1/2 = 2/4
Following Harry Potter's trials in the Chamber of Secrets, wizard researchers found that the somatic cells of the basilisk contain a total of 44 chromosomes. Given this information, how many chromosomes would be expected in the basilisk's gamete, or reproductive, cells?
22
In the wild, potatoes have a diploid number of 24. Cultivated potatoes that we grow for food are tetraploid. How many chromosomes would you expect to find in pollen (i.e., the gametes) from cultivated potatoes?
24
The product rule allows you to quickly figure out the probability of getting certain types of offspring by multiplying the phenotype (or genotype) ratios of multiple genes together. In peas, axial (A) flower position is dominant to terminal (a), tall (L) is dominant to short (l), and yellow (Y) is dominant to green (y). If a plant that is heterozygous for all three traits is allowed to self-fertilize (AaLlYy x AaLlYy), how many of the offspring would show the dominant phenotype for all three traits?
27/64
If THYMINE makes up 21% of the DNA nucleotides in a particular genome, what percentage of the genome is made of Cytosine?
29%
In Labrador Retrievers, coat color is determined by the interaction between two genes. The alleles for one gene influence the color of the pigment in the hair (B is black and b is chocolate brown). The alleles for a second gene influence whether the pigment is deposited in the hair (E is full deposition and e is reduced deposition). Yellow Labrador Retrievers are homozygous recessive for the second gene (ee). A female chocolate Lab (bbEe) is crossed with a male black Lab (BbEe). If this mating resulted in a litter of 8 puppies, how many of those puppies would you expect to be chocolate?
3
During DNA replication, nascent (new) DNA strands are synthesized in only one direction. Nucleotides are added ONLY to which end of the growing nascent strand?
3' end
Below is a schematic of gene Y which encodes protein Y. The promotor region is indicated in the dotted box and transcription begins immediately following the promoter. Use the information given in the schematic to answer the following question. The mRNA produced by this gene would be how many nucleotides long? (Hint: don't worry abou the 5' cap or 3' poly A tail)
3900
The following questions apply to crosses involving a trait following complete dominance. What is the probability that offspring will show the dominant phenotype from a dominant backcross? What is the correct equation showing how the product rule would be used to calculate the probability of a single offspring having two dominant alleles in a monohybrid F1 cross?
4/4, 1/2 x 1/2 = 1/4
In Guinea pigs, short hair (S) is dominant over long hair (s), rough coat (R) is dominant over smooth coat (r), and black hair (B) is dominant over grey hair (b). These traits follow complete dominance. Two Guinea pigs are crossed. The first has short, rough, black fur and has the genotype Ss Rr Bb. The second has short, rough, grey fur with the genotype SS Rr bb. What is the probability that a single offspring will have the SS RR bb genotype? What is the probability that a single offspring will have the short, smooth, grey fur phenotype?
4/64, 8/64
How would you write this individual's karyotype?
47, XXY
Match the element of RNA-processing to the correct definition.
5' cap- completed co-transcriptionally to protect the growing RNA chain from degredation 3' Poly A tail- completed post-transcriptionally to protect the RNA chain from degradation and help regulate its transport to the cellular locations Spliceosome- completed either co-or post-transcriptionally to remove noncoding regions of a gene
Using the information in the above question, what is the map distance in centimorgans between these two loci?
51.5 mu
A portion of one strand of DNA has the sequence 3′ AATGGCTTA 5′. If this strand is used as a template for DNA replication and is read as the leading strand. Which of the following correctly depicts the sequence of the newly synthesized strand in the direction in which it will be synthesized?
5′ TTACCGAAT 3′
Drosophila melanogaster is a species frequently used as a model organism for gene interactions. Below is a typical karyogram of a Drosophila somatic cell before division. Gray (light) chromosomes are maternal, and blue (dark) chromosomes are paternal. Answer the following questions about the genome of this species, based on the karyotype above: 1. How many autosomes does this species have in its genome? 2. Does this species have any sex chromosomes? 3. How many homologous chromosomes are shown in the cell above? 4. How many chromatids are shown in the cell? 5. What is the ploidy of this species?
6, Yes, 8, 8, diploid (2n)
There are _____ different codons that code for amino acids (the other ___ code for translation to stop), but all these codons code for only ____ different amino acids. The fact that there are many more codons than amino acids produced means that the genetic code is ______________.
61, 3, 20 , degenerate (i.e., reduntant)
The following represents a DNA strand in the process of replication. The bottom sequence is that of the template DNA strand with polarity indicated and the top sequence represents the new strand primer (which is made out of RNA, remember, hence the U's). New Strand GGGGCCUUU DNA Template 5′ AAATCCCCGGAAACTAAAC 3′ Which of the following will be the first nucleotide added after the end of the primer?
A
A chromosome contains the following gene order: A B C D • E F G H Which of the following rearrangements represents a pericentric inversion?
A F E • D C B G H
What is DNA barcoding?
A technique for classifying species unique genetic identifiers.
Which of the following double base-pair substitutions is the only mutation that represents a TRANSITION for both base pairs?
AT is replaced by GC
In dominant epistasis, which of the following should have the same phenotype?
A_B_ and A_bb
tRNA's are responsible for bringing the correct amino acid to the ribosome when building a polypeptide. But how do amino acids get onto the tRNA's in the first place?
Aminoacyl-tRNA synthetases add the correct amino acid to the 3' end of the tRNA
In their famous experiment, which of the following would Meselson and Stahl have observed after one cycle of replication in the new 14N medium if DNA replication was conservative?
An equal number of DNA molecules containing two 15N-DNA strands and DNA molecules containing two 14N-DNA strands.
What is eugenics?
An unsupported and oppressive attempt to select desired heritable characteristics to improve future human generations.
Which of the following is the term for the polyploid condition that is formed from the addition of an extra set of chromosomes identical to the normal complement of the same species?
Autopolyploidy
For this pedigree, what is the most likely mode of inheritance for a trait that is rare in population?
Autosomal and X-linked recessive are equally likely
Compared to diploid cells, haploid cells:
Contain half of the total chromosome count (i.e., one set of chromosomes rather than two)
Which arrow(s) point(s) to the location of helicase(s) in the following image?
B and D
Match the species concept to the correct description.
Biological species concept- The most commonly cited species concept; describes species as an interbreeding group reproductively isolated from all other groups Phylogenetic species concept- Defines species as groups with common ancestry; often based on genetic relationships established through tree analysis Morphological species concept- Defines species based on their appearance and phenotype; does not require reproductive isolation Mitonuclear Compatibility species concept- Groups species based on mitochondrial DNA sequence difference and the separates species based on the need for coadaptation of nuclear and mitochondrial gene products
Match the feature on the phylogenetic tree with its correct description.
Branch Tip- Shows the modern or current organism or gene Node- Shows the most recent common ancestor for two organisms or genes Branch Length- Shows the estimated time since divergence from the most recent common ancestor Outgroup- A control used to root a tree because it is known to be different from all other organisms or genes in the tree
Your genetics professor has been playing the latest Pokémon game in an effort to try to remember what it feels like to be young again. One of his favorite Pokémon is Bidoof. Bidoof present with two coat color phenotypes, brown or yellow (see pictures below). While attempting to breed two Bidoof, he notices an interesting phenotypic ratio in the offspring of different crosses. When he crosses a brown Bidoof with another brown Bidoof, he always gets offspring with the brown phenotype. When he crosses a brown Bidoof with a yellow Bidoof, half of the offspring Bidoof are yellow and half are brown (1:1 ratio). When he crosses a yellow Bidoof with another yellow Bidoof, he gets offspring with the ratio 2 yellow : 1 brown. What does this tell him about the genotypes of the two bidoof phenotypes?
Brown is homozygous, yellow is heterozygous, but the yellow allele is recessive lethal when it is homozygous.
You observe that in a population of wild dogs there are five possible phenotypes for coat color. Assuming that coat color is controlled by a single gene, what does this tell you about the inheritance of coat color in these wild dogs?
Coat color must be controlled by multiple alleles.
In sweet peas, the two allelic pairs C, c and P, p are known to effect pigment formation in the flowers. The C & P alleles are dominant to c and p. Importantly, both are necessary for pink flowers. Absence of either (i.e., homozygous recessive in either) results in white flowers. A dihybrid plant is crossed to a white one which is heterozygous only at the "C" locus. Use this information to answer the following questions. What is the genotype of the dihybrid plant? What is the genotype of the white plant? What is the phenotype ratio of the expected offspring from this cross? Which type of epistasis does this represent?
CcPp, Ccpp, 3 pink : 5 white, Complimentary (or Double Recessive) gene interaction
Let's assume D. melanogaster undergoes the same type of mitosis and meiosis as seen in humans. Below are pictures of cells showing only 2 chromosomes (#2 and #3) in each (for simplicity...and because I don't feel like drawing all the chromosomes in each cell). Each cell is depicted at a different stage. Gray (light) chromosomes are maternal and blue (dark) are paternal. Which of the cells above could represent a successful new gamete after meiosis?
Cell 1
Let's assume D. melanogaster undergoes the same type of mitosis and meiosis as seen in humans. Below are pictures of cells showing only 2 chromosomes (#2 and #3) in each (for simplicity...and because I don't feel like drawing all the chromosomes in each cell). Each cell is depicted at a different stage. Gray (light) chromosomes are maternal and blue (dark) are paternal. Which of the cells above could be seen at the beginning of meiosis 2?
Cell 2
Let's assume D. melanogaster undergoes the same type of mitosis and meiosis as seen in humans. Below are pictures of cells showing only 2 chromosomes (#2 and #3) in each (for simplicity...and because I don't feel like drawing all the chromosomes in each cell). Each cell is depicted at a different stage. Gray (light) chromosomes are maternal and blue (dark) are paternal. Which of the cells above could be created from a mitotic division (i.e., somatic growth), but not from normal meiosis?
Cell 3
Match the type of gene regulation with the correct description
Chromatin Remodeling- Controls the availability of genes for transcription by altering the level of DNA condensation and coiling Pre-transcriptional Regulation-Controls both the level of gene expression and whether it is on or off through the use of transcription factors RNA Processing-Controls the formation of the mature RNA message through additions or edits to the nascent RNA molecule or inhibition of its transport Translation Regulation-Controls expression of a gene product by increasing or inhibiting the synthesize of amino acid chains Post-translational Regulation- Controls the function and longevity of protein products encoded by genes through the addition of structural changes or modifications to the protein product
Homologous chromosomes are _____________
Chromosomes with the same function, but potentially different genetic sequence
A true-breeding blue-shelled turtle and a true-breeding orange-shelled turtle are crossed to produce hybrid offspring. The offspring all show shells with individual segments that are either blue or orange. If shell coloration is determined by a single gene, what is the most probable mechanism of inheritance for shell coloration in this species? Based on the mechanism of inheritance described, if you measured the amount of blue and orange pigment in the blood of F1 turtles, how much of each pigment would you expect to find in a given blood sample?
Codominance, Equal amounts of blue and orange pigment
Match the mode of inheritance with the relationship observed between genotype and phenotype.
Complete dominance- The phenotype of a heterozygote is indistinguishable from the phenotype of an individual homozygous for the dominant allele Incomplete dominance- Produces heterozygotes with phenotypes that differ from either homozygote; heterozygote phenotype is similar to a blend of the homozygote phenotypes Codominance- Both alleles are detected equally in the heterozygous phenotype, so the heterozygote appears to clearly show BOTH allele phenotypes.
I wasn't planning on making another Bidoof question, but here we are. In an attempt to understand DNA replication in Pokemon, scientists have replicated the original experiment performed by Meselson and Stahl. In this experiment, scientists took a small biopsy of liver cells from a Bidoof and grew them on nitrogen rich media plates. Just like in the Meselson and Stahl experiment, the scientists let the cells grow in media with heavy nitrogen isotopes (N15). They then switched the cell cultures to light nitrogen isotope (N14) media and let the cells replicate to create 3 generations of cells. At each generation, the scientists centrifugated samples of the cell cultures and looked at the thickness of the bands in the tube. The graph below shows the results. Based on the results shown above, what model of replication does Bidoof DNA follow? What does the fact that there is no hybrid DNA indicate?
Conservative The original DNA with N15 isotopes is not used as a template for new strands of DNA - new DNA is synthesized entirely from new N14 isotopes
The central dogma states that
DNA is transcribed into RNA, which is translated into protein
Transcription occurs during the Central Dogma at which of the following points
DNA to RNA
The Central Dogma of Biology states which of the following
DNA to RNA to Protein
How did Darwin and Mendel differ in their understanding of inheritance?
Darwin saw traits as continuous features that could be "blended" upon inheritance, while Mendel saw traits as discrete.
True or False: When undergoing cell division, only bacteria have an origin of replication. Eukaryotic cells, do not.
False
"All mammals have mitochondrial DNA. Humans are mammals. Therefore, humans have mitochondrial DNA." This statement is an example of what type of reasoning?
Deductive
You finally get your dream job of becoming a medical geneticist at a prestigious research hospital. As a new hire, your boss gives you your first task. She presents you with two diseases (we will call them Disease A and Disease B) that result from two different forms of non-mendelian inheritance. However, both diseases are caused by alleles that code for misfolded proteins in their mitochondria! Your boss asks you to determine which disease follows codominance and which follows incomplete dominance. Use the following information to match the disease with the correct form of non-mendelian inheritance. In Disease A, homozygous dominant individuals have mitochondria with 100 micrograms of misfolded proteins. Homozygous recessive individuals with Disease A have mitochondria with 200 micrograms of misfolded proteins. Heterozygous individuals that carry Disease A have 150 micrograms of misfolded proteins in their mitochondria. In Disease B, homozygous dominant individuals have mitochondria with 200 micrograms of normal proteins. Homozygous recessive individuals with Disease B have mitochondria with 200 micrograms of misfolded proteins. Heterozygous individuals that carry Disease B have 100 micrograms of misfolded proteins and 100 micrograms of normal proteins in their mitochondria.
Disease A- Incomplete dominance Disease B- Codominance
A tRNA in the P site of the ribosome will enter the ________ site after translocation of the ribosome.
E
_________ is a process of cell division observed in all eukaryotes (possessing a true nucleus), whereas __________ is a process of asexual reproduction carried out in all prokaryotes.
Mitosis, binary fission
Which histone protein is not part of the core nucleosome structure?
H1
Why are frameshift mutations usually more dramatic than base substitutions?
Frameshifts affect more than one amino acid.
Match the terms with the corresponding definition (not all definitions will be answers).
Genotype- set of alleles carried by an organism Locus/ loci- the position of a gene or mutation on a chromosome Genes- sections of DNA that code for a specific trait Alleles- different forms of the same gene Phenotype- physical appearance of a trait
A mutation in which kind of cell is most likely to be passed along to your offspring?
Germ cells
Use the following amino acid codon chart to help you answer the following questions. Let's say you have an extremely short mRNA sequence that is being read by a ribosome to make a peptide. The sequence reads, 5' AUGCAACGAGGUUGA 3' What is the first amino acid added to the growing peptide AFTER the start codon? What amino acid does the FINAL codon of this mRNA sequence code for?
Glutamine, It doesn't code for any amino acid
Match the scientist with their achievement
Gregor Mendel- demonstrated that heredity is transmitted in discrete units Wilhelm Johannsen- coined the terms "gene", "genotype", and "phenotype" Rosalind Franklin- discovered the helical structure of DNA using x-ray diffraction (this work was later stolen without consent) Margit M. K. Nass- described mitochondrial DNA for the first time in chick embryos Frederick Sanger- developed the most common method for rapid DNA sequencing Alfred Hershey and Martha Chase- confirmed that DNA was the genetic material responsible for inheritance
DNA helicase inhibitors are well studied as potential drug targets. What would you expect to see if DNA helicase activity is inhibited? If Single-Stranded Binding protein (SSB) is not present during DNA replication, what would you expect to see?
Helicase catalyzes ATP hydrolysis and DNA strands separation, so the helix cannot be unwound and strands will not separate. SSB prevents reannealing of the separated strands, so strands would quickly reanneal and DNA replication cannot proceed.
Huntington's Disease is an autosomal dominant trait that follows complete dominance. The disease is lethal in both homozygous dominant (AA) and heterozygotes (Aa). Yet, somehow, this trait persists in the human population. How does the allele for this trait avoid being lost from the population, even though its phenotype is lethal? A pedigree for a family with Huntington's in their lineage is shown below. If individual IV-2 has children with an unaffected man, what is the probability that their first child will have Huntington's?
Huntington's shows delayed expression, 2/4
Individuals have been identified who have two different karyotypes present among cells in their bodies, such as 45, X in one cell and 46, XX in another cell. Such cases are called ________.
Mosaic aneuploidy
A resident in Stardew Valley has recently figured out how to breed blue chickens. When he bred white chickens with brown chickens, expecting that brown plumage would be the dominant phenotype, there was instead a third phenotype of blue chickens occurring at a ratio of 1 white : 2 blue: 1 brown. What kind of mechanism of non-mendelian inheritance can explain this outcome?
Incomplete dominance
Incomplete dominance and epistasis are two terms that define genetic relationships. Which of the following statements best describes the differences or similarities between the two terms?
Incomplete dominance describes the interaction of two alleles on one gene; epistasis describes the interaction of two genes and their respective alleles.
"Mitochondria contain DNA. Mitochondrial DNA is circular. Therefore, all DNA is circular." This statement is an example of what type of reasoning?
Inductive
Segments of DNA in a transcriptional unit that prevent the transcription of a non-target gene are called ____ ?
Insulators
Use the codon chart below to answer the following questions: Which amino acid is most similar to the start codon? What amino acid do stop codons code? If a codon coding for tryptophan had a point mutation occurring at the 3rd position, changing G --> A, what sort of mutation would occur?
Isoleucine, No amino acid, Nonsense
Before translation, how does the eukaryotic ribosomal small subunit recognize the start codon on the mRNA?
It binds an Met-tRNA to the first AUG codon AFTER the Kozak sequence.
What does it mean for a trait to be dominant?
It will mask the expression of any recessive allele present for the same trait
Match the functional element of translation with the correct definition.
Large ribosomal subunit 60S- contains the E, P, and A sites used to elongate the peptide chain during translation Small ribosomal subunit 40S- reads, recognizes, and binds to the mRNA strand Aminoacyl tRNA synthetase- catalyzes the reaction that adds the correct amino acid to a tRNA GTP- charges the tRNA so it can transfer its amino acid to the growing peptide chain Release factor- bind to the A site of the ribosome and signal the peptide chain and ribosome to dissassociate from the mRNA Initiation factor- prevent the wrong tRNA's from entering the A site
Match each observation with the correct Mendelian Law that it applies to -When an organism is heterozygous for a trait, only the dominant allele will produce a phenotype -Only one of the two alleles for any particular gene present in an organism is distributed to each gamete (sperm or egg) and that this allocation of alleles is completely random -When two or more alleles are inherited, the assortment of one allele does not influence the assortment of any other allele, giving different traits an equal opportunity of occurring together.
Law of Dominance- When an organism is heterozygous for a trait, only the dominant allele will produce a phenotype Law of Segregation- Only one of the two alleles for any particular gene present in an organism is distributed to each gamete (sperm or egg) and that this allocation of alleles is completely random Law of Independent Assortment- When two or more alleles are inherited, the assortment of one allele does not influence the assortment of any other allele, giving different traits an equal opportunity of occurring together.
We learned that certain rearrangements can be seen visibly by looking for loop structures on chromosomes on a karyogram. Scientists can use the banding patterns to identify which type of loop they are looking at and what type of rearrangement resulted in that chromosomal change. Using depictions of the loops below, match the loop to the rearrangement type. The normal gene order is ABCDEFG.
Loop 1-Inversion loop Loop 2-Deletion loop Loop 3-Duplication loop
Let's say that, hypothetically, humans have a gene that enables them to use magic if they inherit the right allele. Using the following observations, determine the mode of inheritance for the ability to use magic in humans. 1) Individuals homozygous for one version of the allele can use magic 2) Individuals that are heterozygous cannot use magic 3) You observe a family. Both parents cannot use magic, but their child is a magic-user. Select the BEST answer from the given possibilities.
Magic use is recessive. Both parents must have been heterozygous.
The above referenced karyogram was created using white blood cells. However, when you examine liver cells from the same individual you obtain the karyogram shown below. What best describes the difference between the karyotypes determined from the two karyograms (from white blood cells vs from liver cells)?
Mosaicism
Who first discovered that mitochondria contain their own DNA?
Margit M. K. Nass and Sylvan Nass, using electron microscopy and chick embryos
Match the shaded regions to the correct term describing the grouping.
Monophyletic- red grouping Polyphyletic- blue grouping Paraphyletic- yellow grouping
Given the information you gathered from the previous questions on the two karyograms, what biological process involving cell division best explains the observed differences between the karyograms from liver and white blood cells?
Nondisjunction in Mitosis (potentially early in development)
Match each definition to the correct component of the cell.
Nucleus- Contains DNA surrounded by a double membrane called the nuclear envelope Ribosome- Synthesizes new proteins from mRNA with the help of rRNA Mitochondria- Contains a circular genome with usually only 37 genes that code for proteins Centrosome- Is the main microtubule organizing center (MTOC) in most cell types Kineticore- A transient protein structure that binds to centromeres and eventually attaches to spindle fibers Centromere- A condensed region of the chromosome where the sister chromatids join together
What kind of bond is formed between the 5' phosphate group (PO4) of one nucleotide and the 3' hydroxyl (OH) group of the adjacent nucleotide? What kind of bond is formed between complementary base pairs to join the two DNA strands into a double helix?
Phosphodiester Bond, Hydrogen bond
What sort of bond links the backbone of DNA? What sort of bond is responsible for the interaction between two nucleotide bases in DNA?
Phosphodiester bond, Hydrogen bond
Match the post-translational modification to the correct definition.
Phosphorylation- a reversible process catalyzed by kinases used to regulate the cell cycle, cell growth, and apoptosis Acetylation- a co- and post- translational process that affects gene expression and modifies proteins like histones, p53, and tubulins Glycosylation- a major post-translational modification that affects protein folding, stability, and activity through the addition of sugars Ubiquitination- a modification that marks proteins for degradation and recycling Methylation- a common modification with a major role in epigenetic gene regulation by affecting the availability of DNA for transcription
What is the purpose of alternative splicing in eukaryotic cells?
Produce multiple polypeptide sequences from a single primary transcript
Sex chromosomes (X and Y) are able to engage in Crossing Over to exchange genes during prophase of Meiosis 1. What part of these chromosomes allows them to do this?
Pseudoautosomal regions (PARs)
Match the chromosome depictions below with the correct rearrangement type shown.
Rearrangement 1-Inversion Rearrangement 2-Deletion Rearrangement 3-Translocation Rearrangement 4-Duplication
You are looking at the color of scales in lizards and find that yellow lizards (Y) are dominant to green lizards (y). However, a second gene, H, controls whether the color will be expressed in the scales. If the lizard is hh, the lizard will always be white, because the pigment does not go into scales. What type of epistasis does this situation represent?
Recessive epistasis
What must eukaryotes do to initiate transcription of a gene immediately after pre-recognition is complete?
Recruit the transcription factors and RNA Polymerase that compose the pre-initiation complex.
Why are telomeres problematic for eukaryotic chromosome replication as we age, even in normal cells?
Removal of the lagging strand primer leaves a gap in one of the strand's DNA sequences.
Which type of mutation is possible due to the redundant nature of the genetic code?
Silent
In a population of bats, a researcher identifies two phenotypes, Long Ear and Short Ear. The researched decides to cross a pure-bred Long Eared female with a pure-bred Short Eared male. The F1 individuals are selfed to produce the F2 generation. The results each generation are shown as phenotypic ratios below: P - Long Eared Female x Short Eared Male F1 - 1 Long Eared Males : 1 Long Eared Females F2 - 2 Long Eared Females : 1 Long Eared Males : 1 Short Eared Males (no short-eared females are observed) What is the most probable Mode of Inheritance for SHORT ears?
Sex-Linked Recessive
Professor Oak has two psyducks! The wildtype psyduck has some interesting phenotypes. Here, you see a shiny morph (S) with two hairs (T) and no headaches (A). Professor Oak has asked you to find the recombination frequency between these traits, and then map them on a chromosome. Psyduck are incredibly prolific, and the cross has already been set up, generating the following data (Note: + refers to wildtype):
TAS, 12.9, 19.7, 6.8
You are a researcher seeking to create a mutation that prevents recognition and access of RNA polymerase to transcribe a gene. Which region of the gene would you mutate?
TATA promoter sequence
Let's pretend you are looking at the activity of a particular enzyme in a bacterial cell. You know this enzyme is coded for by a single gene that exists as two possible alleles, A or B. The amount of enzyme activity in a cell that is homozygous for the A allele is 400 AU (arbitrary units). The amount of enzyme activity in a cell homozygous for the B allele is 200 AU. The amount of enzyme activity in a heterozygote is 300 AU. Based on this discovery, what must the dominance relationship be between the A and B alleles?
The A and B alleles show incomplete dominance.
After winning the Nobel Prize for your work on the enzyme in the previous question, you decide to start another experiment looking at a different enzyme-producing gene in your bacteria. This new gene codes for an enzyme that changes the color of bacterial colonies, red vs blue. This gene exists as two possible alleles, C or D. The C allele codes for a blue-producing enzyme. The D allele codes for a red-producing enzymes. When you measure the enzyme activity of cells again, you record the following measurements. Homozygous for the C allele: 400 AU from blue-producing enzymes. Homozygous for the D allele: 400 AU from red-producing enzymes. Heterozygous cells: 200 AU blue-producing enzymes, 200 AU from red-producing enzymes. Importantly, the activity of the blue-producing enzymes does not seem to affect the activity of the red-producing enzymes. Based on these observations, what must the dominance relationship be between the C and D alleles?
The C and D alleles are codominant
CRISPR is a popular and powerful method for editing genomes. Which of the following statements accurately summarizes how the system works according to the videos in Module 2?
The Cas9 protein is guided to a specific place in the genome by guide RNA. The Cas9 protein cuts the DNA and a new sequence is inserted by taking advantage of the cells own repair mechanisms.
Sex determination in XY systems (like humans) is controlled by a single locus. Which of the following statements best explains how this locus determines sex of developing offspring?
The SRY gene on the Y chromosome produces a transcription factor that activates male gonadal development
What is meant by the "beads on a string" model of chromatin?
The beads are the nucleosomes, and the string is the linker DNA.
Which of the following is true of the gametes of an XX woman whose germ cell undergoes nondisjunction of the X chromosomes during meiosis I?
The gametes contain 22 or 24 chromosomes
What is genetic engineering?
The genetic modification of the characteristics of an organism through changes to its genome.
What is the difference between the kineticore and the centromere?
The kineticore is transient while the centromere remains stationary.
"Silent" mutations are called this because
They do not change the encoded amino acid sequence
According to the information in module 2, what is often a primary goal of a clinical (or medical) geneticist who works in biomedicine?
To analyze the genetic origin of certain diseases so medication or treatments can be created to target the causes of these disorders.
The most common form of gene expression regulation in both prokaryotes and eukaryotes is ____ ?
Transcriptional control
Considering chromosomes 14 and 21, a person who is a carrier of down syndrome will have one copy of chromosome 14, one copy of chromosome 21, and one 14-21 translocation chromosome
True
A female with type O, N, Rh+ blood has children with a male with type AB, MN, Rh- blood. Which of the following children could be conceived by this couple?
Type B, MN, Rh-
A woman with type O, N, Rh+ blood is married to a man with type A, MN, Rh- blood. Which of the following children could have been conceived by this couple?
Type O, N, Rh+
Remember, DNA replication can occur in both directions at once in eukaryotes because they have multiple origins of replication. Based on the following replication bubble, where two replication complexes are working in both directions, which of the following labels for the new DNA strands W, X, Y, and Z is ACCURATE?
W and Y are leading strands, X and Z are lagging strands.
Insertion of a retrotransposon near the VvmybA1 gene in grapes is responsible for the production of what color grapes?
White
What would happen if sister chromatids were separated instead of homologous chromosomes in Meiosis I?
Without reduction division, the process of meiosis 1 would just be mitosis. This would result in two identical diploid daughter cells.
Red-green color blindness is an X-linked recessive disorder in humans. We will label the alleles for this trait as XN for normal and XB for colorblind. A human female has normal vision, even though her father was colorblind. She has children with a male with normal color vision. What is the genotype of the female? What is the probability that their first child will be colorblind? What is the probability that their first child will be a colorblind female?
XN XB, 1/4, 0/4 (not possible)
Match the sex determination system with its proper description
XY system- In this system, males are the heterogametic sex and females are homogametic XO system- In this system, the number of sex chromosomes determines the sex of developing zygotes ZW system- In this system, females are the heterogametic sex and males are homogametic Haplo-diploid- In this system, ploidy determines the sex of developing zygotes Environment dependent- In this system, sex is determined by one or more external factors that influence autosomes
In peas, the trait from the yellow allele (Y) is dominant over the trait from the green allele (y). A plant with yellow peas was crossed to a plant with green peas. The resulting plants were 50% yellow and 50% green. What are the likely genotypes of the parents in this cross? Which of Mendel's Big 6 crosses does this match to?
Yy x yy, Backcross (recessive)
In the flower petals of a particular plant species, the synthesis of red pigment requires two steps in a biochemical pathway as follows: Start with Yellow pigment --> gene A --> Orange Pigment --> gene B --> Red pigment The production of the enzyme required to turn the yellow pigment into the orange is encoded by the dominant A allele. The production of the enzyme required to turn orange pigment into red is encoded by the dominant B allele. A pure-breeding orange flower plant is crossed to a pure-breeding yellow flowered plant to produce F1 progeny that consists entirely of red flowered plants. What is the genotype of the yellow parent? What is the only possible genotype that produces a pure-bred orange flower? If the red F1 progeny are self-crossed, what is the ratio of phenotypes observed in the F2 generation?
aaBB, AAbb, 9 Red : 3 Orange : 4 Yellow
In mice, black coat color is dominant to white coat color. In the pedigree below, mice with a black coat are represented by darkened symbols, and those with white coats are shown as open symbols. Males are squares and females are circles.
heterozygous
This diploid fish displays three eye color phenotypes (blue, green, and yellow). In this species eye color is controlled by a single gene with two possible alleles. The B allele codes for blue eyes, and the Y allele codes for yellow eyes. While studying a population of these fish in a local stream, Auburn scientists discover that yellow-eyed individuals produce 4x as many offspring in their first clutch of eggs compared to blue-eyed individuals. Green-eyed individuals produce 2x as many offspring compared to blue-eyed individuals. They discover that the eye color gene encodes for a protein that controls the amount of yellow pigment the fish absorb in their diet. It turns out, this yellow pigment also works as an antioxidant in fish eggs! Eggs with more of the yellow pigment tend to be healthier, allowing more offspring to hatch. Because this single gene affects both eye color and fish egg hatching success, we say that it is: After observing the yellow and green fish in captivity over the entire year, the scientists also discover that the yellow fish only live 1/4 as long as blue fish. Likewise, the green fish only live half as long as blue fish. So, it seems that even though the Y allele allows the fish to have more offspring early in life, it causes worse effects of aging later in life. Based on this observation, the scientists conclude that this allele shows signs of:
pleiotropic, antagonistic pleiotropy
In Tigriopus californicus copepods, different alleles for a gene that codes for proteins in the mitochondria affect the copepod's ability to produce energy. However, a change to this gene can also cause changes in reproductive traits and longevity. This phenomenon, of one gene affecting many phenotypes, is an example of ______________.
pleiotropy
Which region(s) of a gene are NOT found within the finished mRNA transcript?
promoter and termination region
What are the DNA regulatory sequences that are recognized by RNA polymerase to aid in its recruitment called?
promoters
Normally, a monohybrid cross results in a phenotype ratio of 3:1. However, in some cases, the phenotype ratio from a monohybrid cross can be distorted, to where the phenotype ratio appears as 2:1. In this event, what is the likely mechanism of inheritance for a single gene with this type of phenotypic ratio?
recessive lethal
What type of cross involves pairing two strains "in both directions"? In other words, pairing a maternal strain with a paternal strain, and then making the exact opposite pairing as well?
reciprocal
Sister chromatids are _____________
replicated, identical copies of the same DNA molecule attached to each other
Karyotypes are a method for displaying chromosomes by grouping them into homologous pairs based on what two distinguishing factors?
size and banding pattern
A chromosome has broken, and a piece of one chromosome is translocated to a non-homologous chromosome. This is an example of what type of chromosomal alteration?
unbalanced translocation