1. Chromosomes, colored bodies, are composed of proteins and DNA. In human somat
ID: 10319 • Letter: 1
Question
1. Chromosomes, colored bodies, are composed of proteins and DNA. In human somatic cells there are 23 chromosome pairs. In human somatic cells there are ___ nuclear DNA molecules. a. 23 b.1023 c. 46 d.1046 e. 92
2. Mitotic cell division produces identical daughter cells by ___ DNA replication and _____ cell division(s). a. 1 & 1 b. 1 & 2 c. 2 & 1 d. 2 & 1 e. none of these is correct
3. If we follow meiosis in a diploid heterozygote, the two alleles are, following the first cell division,
a. no longer together in one cell b. together on a chromatid c. present only as
mutants d. blended into a new mix e. chromatids
4. Mendel's Law of Independent Assortment basically states that the alleles of two or more genes segregate independently within and between loci; the chromosomal explanation of this observation is
a. alignment of nonhomologous chromosomes at metaphase I
b. alignment of nonhomologous chromosomes at metaphase II
c. alignment of mitochondria at anaphase
d. misalignment of tetrads during mitosis
e. very much like transformation
5. Knowing that the segregation ratios for a set of loci are all 1/2 : 1/2, we can
predict the frequencies of all possible gametic types by multiplying, if the loci are
a. on different chromosomes and independent b. linked c. on the same
chromosome and dependent d. mitochondrial e. both c & d must hold
6. Watson and Crick used model building and the data of other workers to propose a
double helical model for DNA. The data of Maurice Wilkins and Rosalind Franklin
was critical and showed that
a. phosphodiester linkages are covalent
b. purines = pyrimidines c. the two chains are held by hydrogen bonds
d. the DNA molecule is a double helix e. bases face the axis
7. The DNA structure proposed by Watson and Crick suggested a replication model which was tested by Meselson and Stahl. They used nitrogen isotopes to label replicating DNA which was then separated into bands on a density gradient. The three possible models of replication predicted different numbers of bands after one and then two DNA replications. For the conservative model of DNA replication two bands were expected after the first round of replication. The
semiconservative model predicted the presence of _____ bands after the first
DNA replication. a. 2 b. 4 c. 3 d. 1 e. 8
8.One reason that parents in many cultures have for centuries asked that their children
marry their "own kind" was the belief that the material basis of inheritance was
fluid (BLENDING THEORY). Marriage outside their own kind would adulterate
the purity of the blood lines. Mendel's experiments refuted this fluid based theory of
inheritance.(Not all parents know this.) The critical observation in Mendel's work
which led to the rejection of BLENDING THEORY was
a. chromosome condensation b. reappearrance of the recessive phenotype in the F2
c. anaphase I pairing d. mitosis e. enteleky
9. Professor Dropkin has been collecting data from couples known to be carriers or
heterozygotes for the STR gene wowzer. The data collected look like this
CHILDREN's PHENOTYPES
WW Ww ww
121 249 130
The expected number of heterzygotes is
a. 250 b. 400 c.125 d. 249 e. 15
10. Using his hypothesis [single locus two allele] the expected number of ww
homozygotes is
a. 18 b. 36 c. 41.25 d. 18.33 e. 125
11. and the expected number of WW homozygotes is
a. 125 b. 19 c. 13.75 d. 36.67 e. 18.33
12. The chi-square value for goodness of fit of this data is
Chi-square = SUM (obs-exp)2/exp
a. 0.0 b. 3.84 c. 0.332 d. 55 e. 0.152
13. The hypothesis [single locus, two allele, wowzer recessive] should be
a. accepted as true b. accepted as consistent with the hypothetical predictions
c. rejected as false d. rejected as unlikely e. rejected as true
14. The basis of inferential(testing) statistical analysis is that data are composed of
two elements,
a. theoretical expectation + error b. mean + standard error
c. dominant + recessive d. alpha + beta e. skew I + skew II
15. The chi-square distribution relates
a. genetics to statistics b. deviation from theoretical value to probability
c. dominants to recessives d. metaphase I to telophase e. bases to sugars
16. Gwendolynn and Igor have decided to marry and procreate. They are worried
because both of them have siblings sufferring from Winkle Syndrome which is
really bad and expressed in homozygous recessives. The chance that Gwendolynn
is a carrier of the allele for Winkle Syndrome is
a. 1/4 b. ½ c. 2/3 d. 1.0 e. 9/12
17. The chance that both Gwendolynn and Igor are carriers is
a. ½ b. 4/9 c. 1/16 d. 1.0 e. 25%
18. The chance that their first-born will have Winkle Syndrome is
a. ½ X ½ b. 4/9 X 1/4 c. 2/3 X 1/4 d. 9/16 X 1/4
19. The cis-trans or complementation test involves infecting a bacterial
cell with two different mutant phage at the same time. If
complementation takes place the two mutants are in _______.
a. oppostion b. separate genes c. one operon d. linkage
20. To map the rII region of T4 bacteriophage, Benzer co-infected E. coli
with different rII mutants and measured the frequency of___________
from the progeny of mixed infection.
a. control b. complementation c. recombination d.linkage
21. In phage crosses or mixed infections recombination frequency is
calculated as the sum of recombinant plaques divided by the total
number of plaques. To estimate very small recombination frequencies
Benzer devised a system in which only recombinant phage could grow
and form plaques. The total number of plaques ( recombinant and
nonrecombinant ) was estimated by plating a greater dilution on a
permissive bacterial strain. If there are 187 recombinant plaques and
the total number of plaques is 10,463, the recombinant frequency is
a. 0.23 b. 0.018 c. 0.32 d. 0.0098 e. 0.103
22. Genetic recombination, both independent assortment of nonhomologous
chromosomes and crossing over between homologues, generates amazing
amounts of genetic diversity and allows the constant generation of novel
multilocus genotypes. T. H. Morgan hypothesized a chromosomal
structure in which genes were linearly arranged along the chromosome
and each gene had a specific location or locus. He also felt that crossovers
took place at random along the chromosomal length. Alfred H. Sturtevant
an undergraduate research assistant in Morgan’s lab realized in 1911 that
this meant recombination could be used to map loci along chromosomes
based on recombination frequency. In a cross of D. melanogaster flies
Sturtevant recovered recombinants and nonrecombinants out of a total of
8000 progeny. His progeny classes were: 3500 Zh, 3500 zH, 500 ZH and
500 zh. He estimated the distance between Z and H as
a. 0.125 b. 22 c. 13.5 % d. 0.083 e. 64
23. . Recombination mapping using the method of Lod scores compares two
hypotheses: _____ and _____.
a. homozygous and heterozygous b. haploid and diploid
c. prokaryotic and eukaryotic d. linked and unlinked
e. chromosomal or mitochondrial
24. In Lod score analysis the recombination distance between the marker
locus and the locus affecting the phenotype is not known. Lod score
analysis
a. requires the analyst to guess at the recombination distance.
b. requires review of the literature to find the best estimate of
recombination rate.
c. requires performance of an arcsin transform on the preliminary data.
d. suggests c2 complementation testing.
e. is only possible using mitochondrial markers.
25. If you can draw in the pedigree and make up the missing parts of this
question, you are SAFE.
3,9 4,6
4,9 6,9 4,9 3,4 4,9 4,9 3,6
The affected mother I2 has a disorder, Labatt’s syndrome, which is
thought to be inherited as a single locus dominant. A group of human
geneticists are attempting to map this disorder. After collecting this pedigree from a family in Coral Gables, they first hypothesized that the marker locus with 3,4,6 and 9 alleles was seen in the affected father’s chromosomes in _________ and ___________ phase configurations.
a. 3 L and 9 l b. 3 l and 9 L
c. 4 L and 6 l d. 3 N and 4 Z
26.Under this hypothesized phase configuration there are _________ non
crossover and ________ crossover progeny.
a. 7 and 0 b. 6 and 1 c. 5 and 2 d. 4 and 3 e. 7 and 1
27. The probability of observing this particular family under the hypothesis
of independent assortment is a. ½ b. ¼ c. ¼7 d. ½7 e. 0
28. If we assume that the rate of recombination is r the probability
of observing this particular family under the hypothesis of linkage is
a. (r)6(1/10) b. ½6(1/10) c. (1-r)6(r) d. ½(1/10) e.
29. The ratio of the probability under linkage and independent assortment is
equal to greater than 1.0. This means that the hypothesis of _______
is supported by the data in this pedigree.
a. dominance b. recessiveness c. linkage d. independent asortment
30. Mutations in the I or repressor gene which produce polypeptides unable
to bind to the operator are termed ____________ mutants, because they
are always __ .
a. constitutive off b. repressible off c. repressible on
d. constitutive on e. lagomorph furry
31.Operons which are repressed by end-product are usually biosynthetic
pathway controls like the tryptophan operon. Mutations in the trpR
gene may prevent formation of the repressor-corepressor complex
(tryptophan-repressor). This leads to a state in which RNA _________
is always able to initiate transcription.
a. DNA trihybrids b. DNA dihybrids
c. polymerase d. furcase e. polypeptide
32.Eukaryotic genes are, for the most part, split by introns so that the bases
which actually encode polypeptides, exons, are separated. This allows
_______________________ of transcribed mRNA to produce different polypeptides. a. operonic processing b. translational processing
c. differential splicing d. continuous looping
e. ubiquitin portage
33. In a two locus model A=2, a=1, B=2 and b=1. In a cross between
two double heterozygotes, progeny with scores ranging from four to eight are seen. The genotypes producing these extreme scores are ________
and ________ . a. AABB and aabb b. AaBb and Aabb
c. AAbb and aaBB d. aabb and AaBb
34.Assume that the model in question 20 applies in the real world and that
there is very little environmental variation. A breeder selects only those individuals with scores of 8 for breeding. Which alleles would you expect to decline in frequency ?
a. a and A b. b and B c. A and B
d. a and b e. B and c’
35.Heritability, h2, is a measure of genetic _________ among individuals
in a population; it is not the percentage of genetic determination in an
____________ . a. polymorphism population
b. determination individual c. control individual
d. differences individual e. variability individual
36. The assumption used in proving the Hardy-Weinberg Equilibrium which
allows algebraic equality of allele and genotype frequencies across the
generations without sampling error is
a. random mating b. allelic independence c. no mutation
d. no selection e. infinite population size
37. The frequency of Bird Brain Syndrome carriers is thirty-two percent, and
the frequency of affected homozygotes is four percent. What is the
frequency of the normal allele?
a. 0.8 b. 0.2 c. 0.3 d. 1.0 e. 0.9
38. Natural selection was described as “survival of the fittest” or “nature red
in tooth and claw”. It is, in fact, nothing more than
a. differences in reproductive rates among genotypes.
b. differential survival. c. differential mutation.
d. differences in heritability among genotypes. e. b and d
39. In forensic case work analysis the Hardy-Weinberg is used to
calculate genotype frequencies from allele frequencies. If an STR
profile is 10,22 and the frequencies of the alleles are p10 = 0.15 and
p22 = 0.14, the expected genotype frequency is _____________ .
a. 0.05 b. 0.042 c. 0.01 d. 0.00005 e. 0.25
40. Ralph is accused of fathering Beatrice’s child. Ralph says that he
is not the father; indeed he denies ever having known Beatrice.
Confident that the child, Waldo has a father the assistant state attorney
asks the forensic lab to conduct one of those new fangled STR
parentage tests on Ralph. Here are the results:
Locus D4S4730 D5S227 D18S38 D22S1376
Beatrice 12,17 9.2,17 11,14 22,30
Child 11,17 9.2,21 14,18 21,30
Ralph 9,11 9,21 10,18 18,21
For D18S38 the paternity index(ratio of alleged father and random
man) is a. 1/ p17 b. 0.5/p18 c. 1/p11
d. 0.5/p11 e. .05 f. 9:3:3:1
41. RNAi comes in many known flavors and we will almost certainly be
treated to many new flavors. The degradation of message [siRNA] or
the down regulation of translation [miRNA] is a function of
a. RNA translation. b. mtDNA. c. copy number variation.
d. allozyme mobility e. percentage of base pairing.
42. Hypothalamic brain-derived neurotropic factor BDNF is a key regulator
of weight and energy balance. In Nature Medicine [April 2009] obesity
and diabetes were controlled in a mouse model system by using an
adeno-associated virus vector to introduce BDNF to induce weight loss
and ____________ targeting BDNF to prevent too much weight loss.
a. auto brain-derived neurotropic polypeptide b. Drosophila
c. miRNA d. splicing factor e. both b and d
43. Human groups may be broadly classified into bioeographic regions;
these correspond to racial groups. Ninety percent of all polymorphisms
are found in all five biogeographic groups, but only ____ percent of all
alleles are found only in specific racial groups.
a. 10 b. 30 c. 50 d. 70 e. 5
Explanation / Answer
The Answer to #7 is D
Related Questions
Navigate
Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.