Biology lecture 3 test
A human female "carrier" who is heterozygous for the recessive, sex-linked trait red color blindness, marries a normal male. What proportion of their female progeny will show the trait?
0
In interphase, if 2N=24, there are ______ chromatids in G1; _____ chromatids in G2; _______ chromatids in S phase or DNA sythesis
0; 48; 48
In pea plants, tall plants are dominant over short, and green are dominant over yellow. If you were to cross homozygous tall, green-podded plants with homozygous short, yellow-podded plants, and then were to cross the F1 individual with a short yellow-pods plant, what proportion of the F2 offspring would you expect to be tall and yellow-podded?
1/4
if a DNA molecule is found to be composed of 40% thymine, what percentage of guanine would be expected?
10%
A group of cells is assayed for DNA content immediately following mitosis and is found to have an average of 5 picograms of DNA per nucleus. How many picograms would be found at the end of the S and the end of G2?
10,10
In a cross between a white-eyed female fruit fly and red-eyed male, what percent of the female offspring will be carriers?
100%
a cell containing 32 chromatids at the start of mitosis would, at its completion, produce cells with _____ chromosomes
16
look at picture: the enzyme that excises RNA primer and fills it with DNA is number ___
2
look at the picture: the enzyme responsible for proofreading base pairing is? (DNA polymerase)
2
if there are 20 duplicated chromosomes in a cell, how many centromeres are there?
20
you have _____ autosomes, ______ sex chromosomes, _____ homologous chromosome pairs in your gamete cell.
22,1,0
how many chromosomes does one human egg cell have?
23
In mitosis, if 2N=12, how many chromosomes would be in anaphase?
24
In Interphase, if 2N=24, there are _____ picograms in G1; _____ in G0; _____ picograms in G2 phase; _____ in S phase or DNA synthesis
24;24; 48;38
In interphase, if 2N=24, there are ______ chromosomes on G1 phase; _____ chromosomes in G2 phase; _______ chromosomes in S phase or DNA synthesis
24;24;24
an organism has 4 pairs of chromosomes. Considering the effects of both independent assortment of chromosome and random fertilization, how many different combinations of chromosomes are possible among the offspring from a random cross between two such organisms?
256
Meselson and Stahl allowed bacteria raised in 15N medium to replicate in 14N medium. At the end of two rounds of DNA replication, they observed ______ bands in their centrifugation tubes which was/were composed of ______.
2; double strands of 14N DNA at the top and strands of 15N DNA based-paired to strands of 14N DNA in the middle
look at picture: an RNA primer is synthesized by _____ (RNA primase)
3
What is the complementary strand to 5' AGCTGTAC 3'?
3' TCGACATG 5'
look at picture for this question: without number ___, DNA polymerase cannot initiate DNA synthesis
4
nucleic acids are assembled in the _____ direction.
5' to 3'
an organism has 6 pairs of chromosomes. Considering the effects of both independent assortment of chromosome only, how many different combinations of chromosomes are possible among the offspring from a random cross between two such organisms?
64
How many chromatids are there in a human cell in G2 phase? how many chromatids are there in a human cell in S phase?
92,92
If a dominant individual has offspring that express the recessive phenotype this must mean that the dominant individual is: a) Aa b) AA c) aa d) Either AA or Aa e) cannot be determined
A
all of these disorders are an example of non-disjunction. Which of the following pairs is not correct? a) Downs Syndrome: Monosomy 21 b) Turners syndrome: XO c) Trisomy: XXX d) Kleinfelter syndrome: XXY e) Jacobs syndrome: XYY
A
sister chromatids are a) duplicate chromosomes held together by a common centromere b) specialized gamete-forming cells c) nonfunctional chromosomes d) homologous pairs of chromosomes e) different in their genetic content
A
when chromosomes replicate: A) the two DNA strands separate and each is used as a template for synthesis of a new strand B) new synthesis occurs in only one direction from where it begins C) one strand of DNA is completely replicated first, and then the second strand is replicated D) there is not enough DNA to distribute to the two daughter cells E) all of these are correct
A
About the Okazaki fragment, which of the following is correct? a) small pieces if new synthesized nucleotides on both parental strands b) ligase links them together to form a new synthesized strand c) they are found on leading strand d) primase synthesizes a short DNA primer to drive its synthesis e) all the above
B
If two flowers that have homozygous red for one and homozygous white for another are crossed and produce pink flowers what inheritance is this? a) complete dominance b) incomplete dominance c) multiple alleles d) co-dominance e) polygenetic influence
B
Nucleic acids (DNA and RNA) are polymers of nucleotides. The structural backbone of nucleic acids contains the following repeating pattern? a) --base--sugar--base--sugar--... b)--phosphate--sugar--phosphate--sugar--... c)--base--phosphate--sugar--base--phosphate--sugar--... d)--base--phosphate--base--phosphate--...
B
Two unlinked loci effect mouse hair color. CC or cc mice are agouti. Mice with genotype cc are albino because all pigment production and deposition of pigment in hair is blocked. At the second locus, the B allele (black agouti coat) is dominant to the b allele (brown agouti coat). A mouse with clack agouti coat is mated with an albino mouse of the genotype bbcc. Half of the offspring are albino, one quarter are black agouti, and one quarter are brown agouti. What is the genotype of the black agouti parents? a) BBCC b) BbCc c) bbCC d) BbCC e) BBcc
B
which does NOT happen during meiosis? a) independent assortment b) production of diploid cells c) synapsis d) crossing over e) segregation
B
which of the following is correct about SSDB proteins? a) to break and re-join two strands so as to relieve the strains b) bind to the separated single strand to keep it open and stable c) break down the base pair bonds between two strands d) synthesize new DNA strand by adding free nucleotides on e) make short RNA primer
B
which of the following statements is FALSE? a) during prophase I, homologous chromosomes pair up and exchange DNA b) during meiosis Iim paired homologous chromosomes move up to the equator of the cell c) in meiosis II the sister chromatids of each chromosome separate d) during anaphase I, homologous chromosomes separate e) Meiosis separates homologous chromosomes in a diploid cell to produce haploid daughter cells containing one copy of each type of chromosome
B
which of the following statements is true of linkage? a) linked genes are found on different chromosomes b) the closer two genes are on a chromosome, the lower the probability that a crossover will occur between them c) all of the traits that Mendel studied- seed color, pod shape, flower color, and others- are due to genes linked on the same chromosome d) the observed frequency of recombination of two genes that are far apart from each other has a maximum value of 100%
B
Cytokinesis is evident in plant cells when A) cleavage furrow occurs around the equator B) chromosomes are observable C) cell plate formation occurs D) a spindle apparatus forms E) prophase begins
C
In humans, male patterned baldness is controlled by an autosomal gene that occurs in two allelic forms. Allele B determines non baldness, and allele b determines pattern baldness. In males, because of the presence of testosterone, allele b is dominant over B. If a man and woman both with genotype Bb have a son, what is the chance that he will eventually be bald? A) 25% B) 50% C) 75% D) 33% E) 0%
C
which of the following are NOT involved in the DNA replication process? a) DNA helicase b) DNA ligase c) DNA replicase d) DNA polymerase e) all of the above are involved
C
Cytosine makes up to 42% of the nucleotides in a simple of DNA from an organism. Approximately what percentage of the nucleotides in this sample will be thymine? a) 16% b) 42% c) 31% d) 8% e) can't be determined
D
Each statement is true of homologous chromosomes EXCEPT: A. homologous chromosomes have specific proteins to cut two strands of non-sister chromatids and re-join them for crossing over in Prophase I. B. Homologous chromosomes contain the same gene, but could have different alleles of the particular gene. C. During DNA replication, homologous chromosomes develop two sister chromatids which are identical copies of each other. D. Homologous chromosomes are genetically identical, but one comes from the father and one comes from the mother.
D
If a type O mother crosses with a type A father, then what are all the possible blood types their children could have? A) O,A, and B B) A and B C) A, B, and AB D) A and O E) A, B, AB, and O
D
In E. coli, there is a gene mutation that alters the primase formation. Which of the following would you expect as a result of this mutation? a) replication will require more DNA templates from another source b) no replication fork will be formed, so no daughter strands will be eventually synthesized c) DNA daughter strand will be synthesized along leading strand and lagging strand, however, no proofreading will occur d) replication fork will be formed without RNA primers synthesized, so no daughter strand will eventually be synthesized e) No DNA primers will be formed
D
an Okazaki fragment has which of the following arrangements? a) DNA polymerase I, DNA polymerase II b) 3' RNA nucleotides, DNA nucleotides 5' c) 5' DNA 3' d) 5'RNA nucleotides, DNA nucleotides 3' e) primase, polymerase, ligase
D
the expected phenotype ratio of the progeny of a SsYy x SSyy test cross is? A) 9:3:3:1 B) 3:1 C) 1:1:1:1 D) 1:1 E) 3:1:1:3
D
which of the following would you expect of a eukaryote lacking telomerase? a) production of Okazaki fragments b) high probability of somatic cells becoming cancerous c) high sensitivity to sunlight d) a reduction in chromosome length in gametes e) inability to repair thymine dimers
D
Blood typing is often used as evidence in paternity cases in court. In one case, the mother had blood type AB and the child had blood type O. What statement can you get? A) the father could have blood type A or B with the homozygous genotypes of both B) the father could have blood type AB C) the father could be of any ABO blood types D) the father must have blood type O E) the child was not biologically related to this mother, he is not the mother's child
E
Each is a difference between meiosis and mitosis except: A. in anaphase I of meiosis,homologous chromosomes separate while in anaphase of mitosis, sister chromatids separate. B. Mitosis creates 2 identical daughter cells while meiosis creates 4 un-identical daughter cells. C. In meiosis I, the cell goes from diploid (2N) to haploid (N), while in mitosis the cell stays diploid (2N). D. Meiosis creates genetic variation while mitosis does not. E. sister chromatids separate from each other in mitosis only
E
What statement is false about autosomes and sex chromosomes? A. There are two types of chromosomes found in human somatic cell. B. There are 44 (22 pairs) autosomes and 2(1 pair) sex chromosomes in a somatic cell. C. Autosomes are not allosomes but sex chromosomes are. D. XX and XY are pairs of sex chromosomes that determine sex in a human while autosomes determine body characteristics in a human. E. there are sex chromosomes in insects, birds, bees, and ants as well.
E
The best answer to describe how chromosomes have genetic variation in Meiosis is?
Fertilization, crossing over, independent assortment
use picture 2: what does A,B, and C represent respectively?
Histone, DNA, nucleosome
DNA replication occurs in _____ phase resulting in _______
S, sister chromatids
Homologous pairs of chromosomes a) consist of two chromosomes the same size and the same genes b) consist of two chromosomes having identical alleles c) consist of two chromosomes that came from one parent d) are found in sperm and eggs e) are found in haploid cells
a
If gene 1 was 8 map units away from gene 2 on a chromosome, this means: a) 8% recombination frequency b) 0.8% recombination frequency c) 8 cm d) 8mm e) 8nm
a
In DNA nucleotides are covalently joined together by: a) 3', 5' phosphodiester bonds to form a repetitive sugar-phosphate chain b) 2',5' phosphodiester bond to form a repetitive sugar phosphate chain c) 2',3' 3',4'
a
colorblindness is more common in men than in women because: a) men have only one X chromosome b) the gene is located on the Y chromosome c) women cannot inherit the gene from their fathers d) crossing over occurs only in women e) men get more copies of the gene than women do
a
homologous chromosomes ______. a) carry information for the same traits b) are identical c) align on the metaphase plate in meiosis II d) carry same alleles e) separate during meiosis II
a
just after telophase I, each cell contains ____ a) one full set of chromosomes, each with two chromatids b) two full sets of chromosomes, each with two chromatids c) one full set of chromosomes each with a single chromatid d) two full sets of chromosomes each with a single chromatid
a
use picture 2: which histones are associated with the linker DNA of a nucleosome? a) histone H1 b) histones H2A and H2B c) histone H3 d) histone H4
a
what is the cell reproductive type of bacteria? a) binary fission b) mitosis c) meiosis d) fertilization e) all the above
a
what is the function of topoisomerase? a) relieving strain in the DNA ahead of the replication fork b) elongating new DNA at a replication fork by adding nucleotides to the existing chain c) unwinding of the double helix d) stabilizing single-stranded DNA at the replication fork e) synthesizing RNA primers
a
which of the following is a monohybrid cross? a) AA X Aa b) AaBB X Aabb c) AaBaCb X AaBbCb d) F1 e) F2
a
which of the following represents the order of increasingly higher levels of organization of chromatin? a) nucleosome, 30-nm chromatin fiber, looped domain b) looped domain, nucleosome, 30-nm chromatin fiber c) looped domain, nucleosome, 30-nm chromatin fiber, nucleosome
a
which of these us a way that the sexual life cycle increases genetic variation in a species? a) by allowing crossing over b) by allowing an increase in cell number c) by increasing gene stability d) by decreasing mutation frequency e) by conserving chromosomal order
a
what is the definition of one map unit?
a 1% frequency of recombination between two genes
DNA polymerase can add nucleotides to?
a free 3' OH end of a growing DNA chain
look at 3rd picture: which type of inheritance does the pedigree represent? a) sex-linked dominant b) sex-linked recessive c) autosomal dominant d)autosomal recessive e) Y-linked
a; sex linked recessive
metaphase is characterized by _______
aligning of chromosomes on the equator
A man who carries an allele of an X-linked gene will pass it on to ________
all of his daughters
Hemophilia in humans is due to an X-chromosome mutation. What will be the results of mating between a normal (non-carrier) female and a hemophiliac male?
all the females will be normal and all the males will be normal
_____ is having an abnormal amount of chromosomes (ex 2N+1) while _____ is having an abnormal amount of chromosome sets( ex 3N)
aneuploidy; polyploidy
DNA replication results in: a) two completely new DNA molecules b) two DNA molecules such that each one contains a strand of the original c) one new DNA molecules 1 old molecule d) one new molecule of RNA
b
If the gene P determines color, the dominant allele P turns the cat purple while homozygous recessive (pp) turns the cat blue. If the gene H determines whether the cat has hair at all, the dominant allele H will give cat hair while the homozygous recessive (hh) will not. Using this information: A cross between a purple hairy cat (homozygous for both traits) and a hairless cat would produce what type of offspring: a) all hairless cats b) all purple hairy cats c) 50% purple and hairy; 50% blue and hairless d)25% purple and hairy; 50% hairless; 25% blue and hairy e) cannot be determined
b
If we cross two dogs with heterozygous alleles for black fur color where black is dominant and brown is recessive what will the offspring be? a) 25% black; 75% brown b) 25% brown; 75% black c) 50% black; 50% brown d) 100% black e) 100% brown
b
a recessive gene is one: a) that is not expressed as strongly as a dominant allele b) whose effect is masked by dominant allele c) that appears only in a heterozygote
b
in cats, black fur is caused by an X-linked allele; the other allele at this locus causes an orange color. The heterozygous is tortoiseshell. What kinds of offspring would you expect from the cross of a black female and an orange male? A) tortoiseshell females; tortoiseshell males b) tortoiseshell females; black males c) orange females; black males d) black females; orange males' e) orange females; orange males
b
look at the picture: which of the following enzymes unwind short stretches of DNA helix immediately ahead of a replication fork? (helicase) a) 2 b) 1 c) 4 d) 6 e) 5
b
the elongation of the leading strand during DNA synthesis a) produces Okazaki fragments b) depends on the action of DNA polymerase c) occurs in the 3'--->5' direction d) does not require a template strand e) progresses away from the replication fork
b
which of the following is incorrect about the DNA replication? a) the replication fork exists in eukaryotic only b) there are no Okazaki fragments formed on leading strands of both prokaryotes and eukaryotes c) to get efficient replication process, both prokaryotes and eukaryotes have multiple origins along the chromosomes, with multiple replication bubbles d) DNA is a double helix structure with only one strand being used as template during replications e) semiconservative model give daughter DNA synthesizing directions from 5' to 3' on leading strand, but 3' to 5' on lagging strand
b
which of these descriptions of the behavior of chromosomes during meiosis explains mender's law of segregation? a) sister chromatids separate during anaphase II b) the two alleles for each gene separate as homologous chromosomes move apart during anaphase I c) the arrangement of each pair of homologous chromosomes on the metaphase plate during metaphase I is random with respect to the arrangement of other pairs
b
your nerve cells never divide to generate daughter cells, they are in _____ phase? a) G1 b) G0 c) G2 d) S e) M
b, G0
which does NOT happen during mitosis? a) separation of chromatids b) separation of homologous chromosomes c) haploid cell d) ploidy remains the same e) chromosomes align in the middle of cell
b,c
look at picture: the role of enzyme number 1 is to
break the hydrogen bonds between DNA strands
Blood type AB is an example of a) complete dominance b) incomplete dominance c) codominance d) pleiotropy e) polygenic inheritance
c
During the "S" portion of interphase, what is the cell doing? a) resting b) general cell metabolism c) synthesizing DNA d) making a spindle e) undergoing differentiation
c
The genotype of blood type B could be: a) Bb and BB b) I^B I^B and I^b I^b c) I^B I^B and I^B I^b d) BB and bb
c
a sexually reproducing animal has two unlinked genes, one for head shape (H) and one for tail length (T). Its genotype is HhTt. Which of the following genotypes is possible in a gamete from his organism? a) HhTt b) T c) HT d) Hh e) tt
c
if a cell has completed meiosis I and is just beginning meiosis II, which of the following is an appropriate description of its contents? a) it has one-fourth the DNA and one-half the chromosomes as the originating cell b) it has half the chromosomes but twice the DNA of the originating c) it has half the amount of DNA as the cell that began meiosis d) it is identical in content to another cell formed from the same meiosis I event. e) none of the above
c
the daughter cells of binary fission are ____ a) structurally identical b) chromosomal different c) genetically identical d) structurally identical and genetically identical
c
when genes are linked, the reason a few of the recombinant genotypes still occur in the offspring is because of a) mutation b) linkage c) crossing over d) natural selection e) independent assortment
c
About 70% of americans have a bitter taste from the chemical phenylthiocarboamide (PTC). The ability to taste this chemical results from a dominant allele (T) and not being able to taste PTC is the result of having two recessive alleles (t). Albinism is also a single locus trait with normal pigment being dominant (A) and the lack of pigment being recessive (a). A normally pigmented woman who cannot taste PTC has a father who is an albino taster. She marries a homozygous, normally pigmented man who is a taster but who has a mother that does not taste PTC. Which genotype would not be an offspring? ( there are two answers) a) AATt b) AAtt c) AATT d) Aatt e) AaTt f) AaTT
c and f
DNA replicates from 5' and 3'. the numbers are related to the ______
carbon number in sugar
the area on a chromosome to let chromatids join together is ______
centromere
a human female "carrier" who is heterozygous for the recessive, sex-linked trait causing red-green color blindness marries a normal male. What proportion of their progeny will have red-green color blindness? a) half of the females and half of the males b) none of the females and all the males c) all the females and none of the males d) none of the females and half the males e) half of the females and none of the males
d
look at picture: which of the following repairs nicked DNA by forming a phosphodiester bond between adjacent nucleotides? (ligase) a) 3 B) 2 c) 4 d) 5 e) 6
d
semiconservative replication involves a template. What is the template? a) DNA polymerase b) single-stranded DNA binding proteins c) mRNA molecule d) one strand of the DNA molecule e) helicase
d
the human X and Y chromosomes ________ a) are called autosomes b) are both present in every somatic cell of males and females c) are same size and have same number of genes d) include genes that determine an individual's sex e) are haploid
d
two unlinked loci effect mouse hair color. AA or Aa mice are agouti. Mice with genotype aa are albino because all pigment production is blocked, regardless of the phenotype at the second locus. At the second locus the B allele (brown agouti coat) is dominant to the b allele (black agouti coat). what would be the result of a cross between two agouti mice of genotype AaBb? a) 50% albino, 25% black; 25% brown b) 75% albino; 10% black, 15% brown c) 25% albino, 50% black, 25% brown d) none of the above
d
when columbines with lavender flowers are mated they produce offspring that make either dark purple, lavender, or white flowers. The ratio is 1 dark purple: 2 lavender: 1 white. This is an example of what kind of non-Mendelian inheritance pattern? a)epistasis b) genetic linkage c) pleiotropy d) codominance or incomplete dominance e) multiple elleles
d
which is NOT correct regarding nondisjunction? a) occurs more frequently in human females over age 35 b) may fail to separate maternal from paternal chromatids c) may fail to separate maternal chromatids from one another or paternal chromatids from one another d) may lead to down syndrome e) separates maternal from paternal chromatids
d
which of the following is correct? a) replication starts at a single origin b) replication is bidirectional c) replication is semi conservative d) all the above
d
which of the following is true of a species that has a chromosome number of 2n= 24? a) the species has 12 sets of chromosomes per cell b) the species has 24 sets of chromosomes per cell c) a gamete from this species has 24 chromosomes d) a gamete from this species has 12 chromosomes e) the species is diploid with 48 chromosomes per cell
d
which of the following statements describes eukaryotic chromosome? a) the number of genes on each chromosome is different in different cell types of a single organism b) it is composed of DNA alone c) active transcription occurs on heterochromatin d) it consists of a single linear molecule of double-stranded DNA e) it is composed of a single closed circular molecule of double-stranded DNA
d
within a double-stranded DNA molecule, adenine forms hydrogen bonds with thymine and cytosine forms hydrogen bonds with guanine. This arrangement ______ a) determines the type of protein produced b) allows variable width of the double helix c) determines the tertiary structure of a DNA molecule d) permits complementary base pairing
d
Gametes differ from body cells in a) having only one member of each pair of homologous chromosomes b) being haploid c) functioning in sexual reproduction d) having half the amount of genetic material e) all the above
e
which of the following best describes the function of telomerase at the telomere? a) it makes special primers that do not need to be removed b) it synthesizes new DNA without the use of a template c) it adds new DNA to both strands of the telomere overhang d) it adds new DNA to the shorter strand of the telomere overhang e) it adds new DNA to the longer strand of the telomere
e
Sperm and egg are ______ which are _______ which contain _____ compared to a _______ which are _____ which contain _______
gamete; haploid; 23 unpaired chromosomes; body cell; diploid; 23 paired chromosomes
in binary fission, the daughter cells are?
genetically identical but not structurally
meiosis results in the production of ____ cells with _______ chromosomes
haploid; unpaired
when the two gametes that fuse to form a zygote contain different alleles of a given gene, the offspring is
heterozygous
when two gametes that fuse to form a zygote contain different alleles of a given gene, the offspring is ______
heterozygous
look at the picture: Number 7 refers to the ____ and is going ______ the replication fork while number 8 refers to the ______ and is going away from the replication fork.
leading strand; towards; lagging strand; away
which enzyme links Okazaki fragments into DNA chain?
ligase
the ploidy is reduced from diploid to haploid during ______
meiosis I
A colorblind boy has a normal mother and a colorblind father. From which parent did he get the colorblind gene?
mother
an important difference between prokaryotic and eukaryotic replication is?
multiple origins of replication in eukaryotes
two albino individuals marry and start a family. their first child is normal in pigmentation. Is infidelity suspected why or why not?
no because each parent has a different allele causing his or her albinism (genetic heterogeneity)
which of the following is an example of incomplete dominance? a) the ABO blood group in humans b) skin pigmentation in humans c) pink flowers in snapdragons d) white and purple flower color in peas
pink flowers in snapdragons
Marfan syndrome, a dominant single-gene defect, is characterized by lens dislocation, long limbs, spindly fingers, a caved-in chest, and a weakened aorta. This is an example of a ______ trait
pleiotropic
before the hershey-chase experiment, many scientists believed that _____ carried the hereditary information.
proteins
in what phase would microfilament (actin) ring contract to pinch cell and nuclei and start to reform on opposite poles in mitosis?
telophase
DNA polymerase cannot replicate ______
the 3' end of the linear chromosome
what is crossing over?
the exchange of homologous portions of non sister chromatids
you test cross heterozygous purple-flowered, long-pollened pea plant with homozygous recessive plant, and get mostly purple-flowered and short-pollened plants and white flowered long pollened plants, with very few purple flowered, long pollened or white flowered short pollened plants. What is the most likely explanation?
the genes are linked
When genes are linked, what does this mean?
the genes are located on the same chromosome
Men with red-green color blindness inherited the genes for it from:
their mothers
During DNA replication what is the first process to occur?
unwinding of the parental DNA