GENETICS Exam 4 PT 1
The cells of a mature pea plant have 14 chromosomes. In a pea plant ovary, how many chromosomes would the nucleus of a megaspore contain?
7
In prokaryotes, replication usually begins at a specific place on the chromosome called the:
Origin of replication
In tissue from the intestinal epithelium of a frog, the following proportions of cells were found at each stage of the cell cycle: Interphase-0.90, Prophase-0.04, Prometaphase-0.02, Metaphase-0.01, Anaphase-0.02, Telophase-0.01. If the entire cell cycle in the frog epithelium cells requires 20 hours for completion, what is the average duration of each stage?
18 for interphase, 0.8 hour for prophase, 0.4 for prometaphase, 0.2 hour for metaphase, 0.4 for anaphase, 0.2 for telophase.
The process of splitting the cytoplasm, which separates one cell into two, is termed:
Cytokinesis
A dividing eukaryotic cell is treated with a drug that inhibits the molecular motors associated with kinetochores. At which cell cycle stage would it stop?
M (metaphase)
Which of the following occurs during prometaphase?
Microtubules attach to the kinetochores.
In eukaryotes, chromosomes do NOT contain:
Ribosomes
In Mendel's peas, purple flower color is dominant to white. From which of the following descriptions can you not infer the genotype completely? a. Purple b. White c. Pure-breeding purple d. Heterozygous e. More than one of the above
a
Two gene loci, A and B, assort independently, and alleles A and B are dominant over alleles a and b. Indicate the probabilities of producing the following: a. An AB gamete from an AaBb individual? b. An AB gamete from an AABb individual? c. An AABB zygote from a cross AaBb × AaBb? d. An AaBb zygote from a cross AaBb × AABB? e. An Aabb zygote from a cross AaBb × AAbb? f. An AB phenotype from a cross AaBb × AaBb? g. An AB phenotype from a cross aabb × AABB? h. An aB phenotype from a cross AaBb × AaBB?
a. 1/4 b. 1/2 c. 1/16 d. 1/4 e. 1/4 f. 9/16 g. 1 (100%) h. 1/4
What is the total number of chromosomes in an egg cell of the rat? a. 21 b. 40 c. 41 d. 42 e. 84
a. 21
Interactions among the human ABO blood group alleles involve _______ and ________. a. co-dominance; complete dominance b. codominance; incomplete dominance c. complete dominance; incomplete dominance d. epistasis; complementation e. continuous variation; environmental variation
a. co-dominance; complete dominance
In animals, the inability to make the pigment melanin results in albinism, a recessive condition. two unaffected parents, who have decided to have three children, have a first child that has albinism (aa). what is the probability that the second and third children will also have albinism? a) 1/4 b) 1/2 c) 1/16 d) 9/16 e) 1(100%)
c) 1/16
which of the following is NOT a form of aneuploidy in diploid organisms? a) nullisomy b) monosomy c) disomy d) trisomy e) tetrasomy
c) disomy
In a cross between AaBbCc and AaBbcc, what proportion of the offspring would be expected to be AaB_cc? (B_ means BB or Bb.) a. 3/64 b. 3/32 c. 3/16 d. 3/8 e. 3/4
c. 3/16
What will be the expected ratio of the F2 offspring of the F1 generation? a. 9 "fabulous":7 "plain" b. 13 "fabulous":3 "plain" c. 9 "fabulous":3 "smashing":4 "plain" d. 12 "plain":3 "fabulous":1 "smashing" e. 15 "fabulous":1 "smashing"
c. 9 "fabulous":3 "smashing":4 "plain"
What will be the phenotype(s) of the F1 offspring of a true-breeding "fabulous" father and a true-breeding "plain" mother (aabb)? a. all "plain" b. all "smashing" c. all "fabulous" d. plain" females and "fabulous" males e. "fabulous" females and "smashing" males
c. all "fabulous"
Two gene loci, A and B, assort independently, and alleles A and B are dominant over alleles a and b. What is the probability of producing an AB phenotype from a cross aabb × AABB? a. 1/4 b. 1/2 c. 1/16 d. 9/16 e. 1 (100%)
e
Match each number with the letter most closely associated with it. 1. Turner syndrome 2. Translocation 3. Mosaic 4. Polyploidy 5. Inversion 6. Triploid 7. Tetrasomy 8. Nullisomy a. Extra chromosome sets b. Mitotic nondisjunction c. 2n-2 d. Alternate segregation e. 2n+2 f. Sterile g. 45, X i. ABCDEF > ABEDCF
1. g 2. d 3. b 4. a 5. i 6. f 7. e 8. c
Suppose that a diploid cell contains 8 chromosomes (2n=8). How many different combinations in the gametes are possible?
16
In a certain species of plant, flowers occur in three colors: blue, pink, and white. A pure-breeding pink plant is mated with a pure-breeding white plant. All of the F1 are blue. When the blue F1 plants are selfed, the F2 occur in the ratio 9 blue:3 pink:4 white. How many gene pairs control the flower color phenotype?
2
The cells of a mature pea plant have 14 chromosomes. How many chromosomes does a nucleus in the pea endosperm contain?
21
if both husband and wife are known to be heterozygous for the autosomal recessive condition of albinism, what is the probability that among their four children, three will be normal and one will have albinism?
27/64
A diploid species has a total of 52 chromosomes. How many chromosomes would be found in a nullisomy, autotriploid, and trisomy? a. 50; 78; 53 b. 26; 53; 104 c. 78; 50; 53 d. 50; 53; 78 e. 50; 53; 104
A
Meiosis I is called the ___________ division and meiosis II is called the __________ division. a. reduction; equational b. interphase; prophase c. equational; reduction d. mitotic; interphase e. slow; rapid
A
One diploid species A has 32 chromosomes and another diploid species B has 24 chromosomes. If species A's gamete derived from the non-disjunction of meiosis I fused with species B's normal gamete. How many chromosomes would be in the zygote? a. 44 b. 56 c. 44 or 28 d. 44 or 40 or 28 e. 40
A
Which structural component of a eukaryotic chromosome is the attachment point for spindle microtubules during M-phase? a. the centromere b. sister chromatids c. the origin of replication d. the telomere
A
In order to be functional, a eukaryotic chromosome requires all of the following EXCEPT:
A plasmid
Which of the following statements is TRUE?
Archae are more closely related to eukaryotes than to eubacteria
Prokaryotic chromosomes do NOT have telomeres because they:
Are circular
Why was the pea plant an ideal plant for Mendel to use? a. It produces few progeny. b. It has some traits, which are easy to be observed. c. It requires cross-fertilization; there is no self-fertilization. d. It requires several seasons to complete a generation. e. There were only a few pure varieties available.
B
All of the following make meiosis different from mitosis, EXCEPT: a. meiosis comprises two divisions. b. chromosome number is reduced by half in meiosis. c. resulting cells from meiosis are genetically different from the parent cell. d. meiosis lacks preceding S and G2 phases. e. pairing of homologous chromosomes usually only occurs in meiosis.
D
One hexaploid species has 42 chromosomes. What's the basic chromosome number of this species. a. 21 b. 42 c. 6 d. 7 e. 14
D
Sister chromatids separate and move toward opposite poles during which phase of mitosis? a. prophase b. pro-metaphase c. metaphase d. anaphase e. telophase
D
During meiosis when crossing over occurs in a paracentric inversion loop, what percent of the meiotic products will result in nonviable gametes? a. 0% b. 25% c. 50% d. 75% e. 100%
C
Peanut is an autotetraploid with total chromosome number of 40. What's the chromosome number of peanut gamete? a. 40 b. 10 c. 20 d. 30
C
Which is NOT a type of chromosomal mutation? a. chromosome rearrangement b. aneuploidy c. polyploidy d. point mutation
D
Which of the following events of meiosis creates genetic variation among the gametes? a. crossing over b. random separation of maternal and paternal chromosomes c. distribution of differing numbers of chromosomes to daughter cells d. both a and b e. all of the above
D
___________ can cause genes to move from one linkage group to another. a. Inversions b. Deletions c. X-rays d. Translocations e. Unequal crossing over
D
If a healthy cell passes the G1/S checkpoint:
DNA will be replicated.
Chromosome movement during anaphase is a result of:
Disassembly of tubulin molecules by molecular motor proteins.
Which of the following processes is unique to plants?
Double fertilization
The figure shows a chromosomal separation taking place. The letters stand for genes; capital and lowercase stand for different alleles. The diploid chromosome number in this organism is four. What process is shown? a. anaphase of mitosis b. telophase of meiosis I c. anaphase of meiosis I d. telophase of mitosis e. anaphase of meiosis II
E
Which of the following statements is FALSE?
Errors in chromosome separation are rarely a problem for an organism.
Describe the main differences between meiosis I and meiosis II
Homologs pair and segregate in meiosis I. Sister chromatids are paired and segregate in meiosis II. Crossing over occurs in meiosis I, but not in meiosis II.
The centromere divides a chromosome into two sections or arms. A chromosome is found to have two arms of equal lengths. Such a chromosome can be BEST described as:
Metacentric
The highly organized internal scaffolding of the nucleus is called the:
Nuclear matrix
A chromosome with a centromere at the very end is called:
Telocentric
Which of the following does NOT occur during the G2 phase of the cell cycle?
The cell divides
which type of chromosome mutation increases the amount of genetic material for all chromosomes? a) polyploidy b) aneuploidy c) inversion e) duplication
a) polyploidy
Diploid cells are cells with _____ chromosomes.
Two sets of
A couple has six daughters and is expecting a seventh child. What is the probability that this child will be a boy? a. 1/2 b. 1/4 c. 1/16 d. 1/64 e. 1/128
a
Genes come in different versions called a. alleles. b. loci. c. genotypes. d. chromosomes. e. genomes.
a
Gregor Mendel carried out a cross between two pea plants by taking pollen from a plant that was homozygous for round seeds and dusting the pollen onto the stigma of a plant homozygous for wrinkled seeds. Which of the following would be the reciprocal cross that Mendel had carried out for this experiment? a. Homozygous round stigma pollinated with homozygous wrinkled b. Homozygous round stigma pollinated with heterozygous wrinkled c. Heterozygous round stigma pollinated with homozygous wrinkled d. Homozygous wrinkled stigma pollinated with homozygous round e. Homozygous wrinkled stigma pollinated with homozygous wrinkled
a
Honeybees have a haplo-diploid sex determination system where females develop from a fertilized egg (they are diploid, having one allele from the female queen and one allele from the male), and males develop from unfertilized eggs (they are haploid, having only one allele from the queen). Assuming that the queen is heterozygous for a particular gene, what is the probability that a female will inherit the recessive allele from her mother? What is the probability that a male will inherit a recessive allele from his mother? a. The probability that a daughter will inherit a recessive allele from her mother is 50%; the probability that a son will inherit a recessive allele from his mother is 50%. b. The probability that a daughter will inherit a recessive allele from her mother is 50%; the probability that a son will inherit a recessive allele from his mother is 100%. c. The probability that a daughter will inherit a recessive allele from her mother is 100%; the probability that a son will inherit a recessive allele from his mother is 50%. d. The probability that a daughter will inherit a recessive allele from her mother is 100%; the probability that a son will inherit a recessive allele from his mother is 100%. e. The probability that a daughter will inherit a recessive allele from her mother is 0%; the probability that a son will inherit a recessive allele from his mother is 100%.
a
In a cross between AaBbCcDdEe and AaBbccDdee, what proportion of the offspring would be expected to be A_bbC_ddE_? (A_ means AA or Aa.) a. 3/256 b. 3/32 c. 3/16 d. 3/8 e. 3/4
a
Round seeds (R) is dominant to wrinkled seeds (r), and yellow seeds (Y) is dominant to green seeds (y). A true-breeding pea plant with round and yellow seeds is crossed to a true-breeding plant with wrinkled and green seeds. The F1 progeny are allowed to self-fertilize. What is the probability of obtaining a yellow seed in the F2? a. 3/4 b. 1/16 c. 9/16 d. 3/16 e. 1/2
a
Two gene loci, A and B, assort independently, and alleles A and B are dominant over alleles a and b. What is the probability of producing an AB gamete from an AaBb individual? a. 1/4 b. 1/2 c. 1/16 d. 9/16 e. 1 (100%)
a
Two gene loci, A and B, assort independently, and alleles A and B are dominant over alleles a and b. What is the probability of producing an AaBb zygote from a cross AaBb × AABB? a. 1/4 b. 1/2 c. 1/16 d. 9/16 e. 1 (100%)
a
Which of the following was not one of Mendel's conclusions based on his monohybrid crosses? a. Genes are carried on chromosomes. b. Alleles exist in pairs. c. Alleles segregate equally into gametes. d. Alleles behave as particles during inheritance. e. One allele can mask the expression of the other allele.
a
explanation for why occasionally a baby is found that has the XX chromosomal karyotype but is phenotypically male?
a piece of chromosomal material containing an active SRY gene is found attached to one of the X chromosomes
what would be the consequence of a diploid gamete (resulting from meiotic nondisjunction) being fertilized by a haploid gamete from the same species? a) autotriploid b) allotriploid c) allotetraploid d) autotetraploid e) autodiploid
a) autotriploid
In a cross between AaBbCc and AaBbcc, what proportion of the offspring would be expected to be A_bbcc? (A_ means AA or Aa.) a. 3/256 b. 3/32 c. 3/16 d. 3/8 e. 3/4
b
In poodles, black fur is dominant to white fur. A black poodle is crossed with a white poodle. In a litter of four, all of the puppies are black. What is the best conclusion? a. The black poodle is definitely homozygous. b. The black poodle is probably homozygous. c. The black poodle is definitely heterozygous. d. The black poodle is probably heterozygous. e. The genotype of the black poodle cannot be inferred with this information.
b
Round seeds (R) is dominant to wrinkled seeds (r), and yellow seeds (Y) is dominant to green seeds (y). A true-breeding pea plant with round and yellow seeds is crossed to a true-breeding plant with wrinkled and green seeds. The F1 progeny are allowed to self-fertilize. What is the probability of obtaining a wrinkled, green seed in the F2? a. 3/4 b. 1/16 c. 9/16 d. 3/16 e. 1/2
b
Two gene loci, A and B, assort independently, and alleles A and B are dominant over alleles a and b. What is the probability of producing an AB gamete from an AABb individual? a. 1/4 b. 1/2 c. 1/16 d. 9/16 e. 1 (100%)
b
Why was the pea plant an ideal plant for Mendel to use? a. Generation time that is several years b. Simple traits that are easy to identify c. Low numbers of offspring produced d. Expensive and time-consuming to grow e. All of the above
b
For the parent plants described in the previous question, what is the probability of obtaining offspring that are short and have purple flowers? a. 0 b. 1/8 c. 1/4 d. 1/3 e. 1/2
b. 1/8
What is the total number of chromosomes present in the cell during metaphase I of meiosis? a. 21 b. 42 c. 84 d. 126 e. 168
b. 42
In humans, blood types A and B are codominant to each other and each is dominant to O. What blood types are possible among the offspring of a couple of blood types AB and A? a. A, B, AB, and O b. A, B, and AB only c. A and B only d. A, B, and O only e. A and AB only
b. A, B, and AB only
What is the genotype of the pink parent? (Use symbols of your own choosing.
bbWW
A chi-square test was performed and indicated that the observed numbers of offspring were significantly different from the expected. Which of the following P-values would support this conclusion? a. 0.995 b. 0.536 c. 0.024 d. 0.752 e. 0.159
c
A space capsule crashes to earth with an alien life form aboard. Two creatures emerge from the capsule, one with green skin and one with yellow skin. The yellow creature soon gives birth to offspring fathered by the green creature, producing 12 green and 8 yellow offspring. Green skin in these diploid creatures is dominant to yellow skin. You are curious to find out if the number of offspring significantly different from expected Mendelian ratios, so you perform a chi-square test. What is the chi-square value for this cross? a. 0.2 b. 0.4 c. 0.8 d. 1.2 e. 1.6
c
Freckles are caused by a dominant allele. A man has freckles but one of his parents does not have freckles. The man has fathered a child with a woman that does not have freckles. What is the probability that their child has freckles? a. 1/4 b. 1/3 c. 1/2 d. 2/3 e. 3/4
c
Freckles are caused by a dominant allele. A man has freckles but one of his parents does not have freckles. What is his genotype? a. Homozygous dominant b. Homozygous recessive c. Heterozygous d. Heterologous e. Homologous
c
If an organism of genotype Aa is used for a test cross, what is the genotype of the other individual used in the cross? a. AA b. Aa c. Aa d. The genotype cannot be known e. Either a or b
c
In Labrador retrievers, black coat color is dominant to brown. Suppose that a black Lab is mated with a brown one and the offspring are 4 black puppies and 1 brown. What can you conclude about the genotype of the black parent? a. The genotype must be BB. b. The genotype must be bb. c. The genotype must be Bb. d. The genotype could be either BB or Bb. e. The genotype cannot be determined from these data.
c
In Mendel's peas, yellow seeds are dominant to green. A pure-breeding yellow plant is crossed with a pure-breeding green plant. All of the offspring are yellow. If one of these yellow offspring is crossed with a green plant, what will be the expected proportion of plants with green seeds in the next generation? a. 0% b. 25% c. 50% d. 75% e. 100%
c
In animals, the inability to make the pigment melanin results in albinism, a recessive condition. Two unaffected parents, who have decided to have three children, have a first child that has albinism (genotype aa). What is the probability that the second and third children will also have albinism? a. 1/4 b. 1/2 c. 1/16 d. 9/16 e. 1 (100%)
c
In dogs, black coat color (B) is dominant over brown (b), and solid coat color (S) is dominant over white spotted coat (s). A cross between a black, solid female and a black, solid male produces only puppies with black, solid coats. This same female was then mated with a brown, spotted male. Have of the offspring from this cross were black and solid, and half of the offspring were black and spotted. What is the genotype of the female? a. BBSS b. BbSS c. BBSs d. BbSs e. bbss
c
In dogs, black coat color (B) is dominant over brown (b), and solid coat color (S) is dominant over white spotted coat (s). A cross between a black, solid female and a black, solid male produces only puppies with black, solid coats. This same female was then mated with a brown, spotted male. Have of the offspring from this cross were black and solid, and half of the offspring were black and spotted. Which of the following could be the genotype of the black, solid male? a. BBSs b. BBss c. BbSS d. BbSs e. Bbss
c
Round seeds (R) is dominant to wrinkled seeds (r), and yellow seeds (Y) is dominant to green seeds (y). A true-breeding pea plant with round and yellow seeds is crossed to a true-breeding plant with wrinkled and green seeds. The F1 progeny are allowed to self-fertilize. What is the probability of obtaining a round, yellow seed in the F2? a. 3/4 b. 1/16 c. 9/16 d. 3/16 e. 1/2
c
The ability to curl one's tongue into a U-shape is a genetic trait. Curlers always have at least one curler parent but noncurlers can have one or both parents who are curlers. Using C and c to symbolize the alleles that control this trait, what is the genotype of a noncurler? a. CC b. Cc c. cc d. Any of the above could be correct.
c
Two gene loci, A and B, assort independently, and alleles A and B are dominant over alleles a and b. What is the probability of producing an AABB zygote from a cross AaBb × AaBb? a. 1/4 b. 1/2 c. 1/16 d. 9/16 e. 1 (100%)
c
Which of the following crosses would produce a 3:1 ratio of phenotypes in the next generation? a. AA × AA b. AA × aa c. Aa × Aa d. Aa × aa e. aa × aa
c
In the endangered African watchamakallit, the offspring of a true-breeding black parent and a true-breeding white parent are all gray. When the gray offspring are crossed among themselves, their offspring occur in a ratio of 1 black :2 gray:1 white. Upon close examination of the coats, each hair of a gray animal is gray. What is the mode of inheritance? a. one gene pair with black dominant to white b. one gene pair with codominance c. one gene pair with incomplete dominance d. two gene pairs with recessive epistasis
c. one gene pair with incomplete dominance
In a cross between AABbCcDD and AaBbccdd, what proportion of the offspring would be expected to be A_B_C_D_? (A_ means AA or Aa.) a. 3/256 b. 3/32 c. 3/16 d. 3/8 e. 3/4
d
In a cross between pure-breeding tall plants with pure-breeding short plants, all of the F1 are tall. When these plants are allowed to fertilize themselves, the F2 plants occur in a ratio of 3 tall:1 short. Which of the following is not a valid conclusion from these results? a. The allele that produces the tall condition is dominant to the allele that produces the short condition. b. The difference between tall and short stature in these lines is controlled by a single gene pair. c. During production of gametes in F1 plants, the tall and short alleles segregate from each other equally into the gametes. d. The tall and short traits assort independently of each other in this cross. e. Fertilization occurs randomly between gametes carrying the tall and short alleles.
d
Round seeds (R) is dominant to wrinkled seeds (r), and yellow seeds (Y) is dominant to green seeds (y). A plant of unknown genotype is testcrossed to a true-breeding plant with wrinkled and green seeds. The offspring produced were 53 round and yellow, 49 round and green, 44 wrinkled and yellow, 51 wrinkled and green. What is the likely genotype of the parent in question? a. RRYY b. RrYY c. RRYy d. RrYy e. rryy
d
Round seeds (R) is dominant to wrinkled seeds (r), and yellow seeds (Y) is dominant to green seeds (y). A true-breeding plant with round and yellow seeds is crossed to a true-breeding plant with wrinkled and green seeds. What is the genotype of the F1 progeny? a. RRYY b. RrYY c. RRYy d. RrYy e. rryy
d
Two gene loci, A and B, assort independently, and alleles A and B are dominant over alleles a and b. What is the probability of producing an AB phenotype from a cross AaBb × AaBb? a. 1/4 b. 1/2 c. 1/16 d. 9/16 e. 1 (100%)
d
Which of the following crosses would produce a 1:1 ratio of phenotypes in the next generation? a. AA × AA b. AA × aa c. Aa × Aa d. Aa × aa e. aa × aa
d
Which of the following statements is true? a. The genotype is the physical appearance of a trait. b. Alleles, genes, and loci are different names for the same thing. c. The phenotype of a dominant allele is never seen in the F1 progeny of a monohybrid cross. d. A testcross can be used to determine whether an individual is homozygous or heterozygous. e. All of these statements are true.
d
In dogs, black coat color (B) is dominant over brown (b), and solid coat color (S) is dominant over white spotted coat (s). A cross between a black, solid female and a black, solid male produces only puppies with black, solid coats. This same female was then mated with a brown, spotted male. Have of the offspring from this cross were black and solid, and half of the offspring were black and spotted. What is the genotype of the brown, spotted male? a. BBSS b. BbSS c. BBSs d. BbSs e. bbss
e
Which of the following statements is true? a. The probability of a woman giving birth to three girls in a row is 1/8. b. The chi-square test is used to determine if observed outcomes are consistent with expected outcomes. c. The probability of two or more independent events occurring together is calculated by multiplying their independent probabilities. d. Branched diagrams are used for determining probabilities of various phenotypes or genotypes for genetic crosses involving more than one gene pair. e. All of these statements are true.
e
While doing field work in Madagascar, you discover a new dragonfly species that has either red (R) or clear (r) wings. Initial crosses indicate that R is dominant to r. You perform three crosses using three different sets of red-winged parents with unknown genotype and observe the following data: Cross Phenotypes 1 72 red-winged, 24 clear-winged 2 12 red-winged 3 96 red-winged Which cross is likely to have at least one parent with the genotype RR? a. Cross 1 b. Cross 2 c. Cross 3 d. Crosses 1 and 2 e. Crosses 2 and 3
e
which of the following does NOT bring about evolution in a population? a) small pop. size b) migration of individuals from a pop w/ a diff genetic structure c) mutation d) selection e) random mating
e) random mating
A diploid somatic cell from a rat has a total of 42 chromosomes (2n = 42). What is the total number of telomeres in a rat cell in G2? a. 21 b. 42 c. 84 d. 126 e. 168
e. 168
Suppose that a diploid cell contains 10 chromosomes (2n = 10). How many different combinations in the gametes are possible? a. 64 b. 5 c. 10 d. 20 e. 32
e. 32
with the XX-XO sex determination system, generally:
male offspring have one x chromosome, and it is inherited from their mother
___________ can cause genes to move from one chromosome to another.
translocations