Bio exam 5
29) In meiosis I, cytokinesis usually occurs after telophase I and produces
2 haploid cells
43) In humans, how many of the mother's chromosomes are present in the egg before it is fertilized?
23
73) A healthy, young couple are carriers of cystic fibrosis; the chance that each of their future children will inherit this serious illness is ______%
25%
93) Mendel's monohybrid cross of Tt parents resulted in a tall-to-short ratio of
3:1
99) In the ABO blood type system the alleles IA, IB, and i produce ______ phenotypes.
4
33) In meiosis II, cytokinesis results in the production of
4 genetically unique haploid daughter cells
11) Human zygotes contain a total of ________ chromosomes.
46
44) Genes A and B are on the same chromosome. What gametes could an AABB individual produce, if crossing-over and nondisjunction do not occur?
AB
82) If you, like Mendel, grow plants in the lab, and cross short (tt) pea plants with short pea plants, the offspring will be
All short
75) The DNA sequences, indicated by alphabetic abbreviations, are alternate forms of the same gene called
Alleles
\55) Plants have an intermediate body form called a sporophyte that undergoes meiosis. The cells produced grow, through mitosis, into another intermediate body form called a gametophyte, which divides by mitosis to form gametes. The gametes fertilize, and the zygote grows, through mitosis, into another sporophyte. This form of a sexual life cycle is referred to as
Alternation of generations
28) In meiosis, homologous chromosomes separate during
Anaphase I
32) In meiosis, the separated sister chromatids move to opposite poles of the cell during
Anaphase II
36) Alternate forms of the same gene
Are Alleles
68) In contrast to human X and Y chromosomes, autosomes
Are homologous chromosomes and found in both sexes
21) The human chromosomes that do not determine whether an individual is male or female are
Autosomes
26) In a cell dividing by meiosis, DNA is replicated
Before meiosis I
42) Among variations in human sex chromosomes, individuals who have a single X chromosome are female, while those with XXY sex chromosomes are males. In order to be a female, a human
Cannot have a Y chromosome
53) In humans, the egg provides the mitochondria to the zygote. In plants, which organelles would be provided by the egg and not by the sperm?
Chloroplast and Mitrochodria
100) In the biology lab, you observed that your lab partner's blood type is AB. The placement of the A and B molecules on each cell is controlled by proteins, coded by different versions of the same gene. Having both is an example of
Codominant inheritance
8) The process by which a bacterium uses a sex pilus to transfer genetic information to another bacterium is
Conjugation
45) Genes A and B are on the same chromosome. The genes have alleles A and B on one homologous chromosome, and the alleles a and b on its paired homolog. How could an individual with this allele arrangement produce a gamete with a chromosome containing the alleles Ab or aB?
Crossing over
46) Which of the following may occur in meiosis but not in mitosis?
Crossing over
78) Gametes may carry different combinations of alleles because of
Crossing-over and random alignment of chromosomes
1) A cell with two full sets of chromosomes would be termed a ________ cell.
Diploid
80) Mendel observed that some genetic traits seemed to mask others in the pea plants. The masking trait is referred to as the
Dominant trait
54) Pollen contains ________ that produce ________.
Gametophytes; sperm
74) A portion (location) of DNA that encodes a specific protein is a
Gene
40) What is the major advantage of sexual reproduction over asexual reproduction?
Genetic variability during an ecological disaster
5) In humans, specialized cells that produce gametes are
Germ cells
72) The person who made a lasting impression in the science of genetics with his study of traits in pea plants was
Gregor Mendel
14) The abbreviation n indicates cells are
Haploid
2) A cell with one set of chromosomes would be termed a ________ cell.
Haploid
52) In plants, sporophytes undergo meiosis to produce ________ spores.
Haploid
49) If you mate a donkey (2n = 62) with a horse (2n = 64) you get a mule. Mules are sterile and cannot produce gametes by meiosis because they
Have an odd number of chromosomes
85) "DNA fingerprint" information indicates that you have two different versions of the allele for a particular skin protein. These alleles are called
Heterozygous
97) The F2 generation is determined by using a dihybrid cross mating between two individuals that are each ________ for ________ gene (genes).
Heterozygous; two
24) Chromosomes that look alike and carry the same sequence of genes for the same traits, and come from two parents, are
Homologous chromosomes
84) If the two alleles for a particular gene are identical the gene pair is
Homozygous
95) In a testcross, if all the offspring show the dominant phenotype, then the individual with the unknown genotype was
Homozygous dominant
94) A testcross is a mating of an individual with an unknown genotype and an individual that has a known genotype of
Homozygous recessive
35) The process by which homologous chromosomes exchange genetic material
Is crossing over
66) The movement of a section of DNA from a chromosome to a nonhomologous chromosome is an example of
Translocation during meiosis
39) Nondisjunction may cause
Trisomy 21 Turner syndrome Jacobs syndrome Klinefelter syndrome
56) In spermatogenesis there are two divisions in meiosis, resulting in four daughter cells.
True
57) The number of chromosomes in a daughter cell produced by mitosis is the same as the number of chromosomes in the parent cell.
True
59) In mitosis, homologous chromosomes do not pair up.
True
60) In meiosis, homologous chromosomes pair up, allowing crossing-over to occur.
True
61) If a human zygote has either 45 or 47 chromosomes, it might be assumed that this was due to nondisjunction.
True
63) A female missing an X chromosome (XO) would have Turner syndrome.
True
64) If a woman in her late forties wants to have a baby and seeks medical advice, she would most likely be advised of the risks related to nondisjunction occurring and a higher rate of fetal chromosomal abnormality.
True
65) Identical twins result from one zygote splitting into two genetically identical embryos.
True
69) Without genetic diversity, a population might more easily fall victim to parasites and pathogens.
True
92) Your biology instructor has assigned you a lab exercise to test a hypothesis regarding the inheritance of stem length in pea plants. If your assignment is specifically to conduct a monohybrid cross for stem length from available genotypes growing in the lab, which of the following crosses should be performed?
Tt with Tt
12) Diploid (2n) means having
Two complete sets of homologous chromosomes
67) A size-ordered chart, containing images of all the chromatids (chromosomes) of a cell, is
Used to detect chromosomal abnormalities such as trisomy, A karyotype, Used to detect damages to chromatids, Used to show autosomes and sex chromosomes
83) When Mendel crossed tall (Tt) plants with tall plants of the same genotype, the offspring
Were a variable mix of tall and short
89) The most common phenotype or allele for a gene in a population is referred to as the
Wild-type
23) The normal sex chromosomal combination for a human female is
XX
22) The sex chromosomal combination for a human male is
XY
15) In humans, germ cells are located in the
Testes and ovaries
25) Identify the correct comparison between the human X and Y chromosomes.
The X chromosome is larger than the Y chromosomes, Only the Y chromosome is always found without a homologous match, Only the X chromosome is paired with a homologous match in human females, Although both are sex chromosomes, they do NOT share the same genes
87) Genotype refers to
The combination of alleles in an individual
76) In humans, alleles for each gene are inherited from
The mother AND the father (one allele from each parent)
88) Phenotype refers to
The observable expression of the genes in an individual
13) If human gametes were diploid
The products of fertilization would have MORE chromosomes than their parents
79) Why are pea plants (Pisum sativum) a good species for genetics studies?
They can be self-fertilized for true-breeding genetic traits, They produce large numbers of offspring (the peas), They have many distinctly identifiable forms of genetic traits, Growth of pea plants is simple and easy
86) If an individual is heterozygous for a particular trait
Each parent contributed a different allele for that trait
91) In the study of genetics, the offspring of the parental generation is referred to as the
F1 Generation
70) Caenorhabditis elegans is a hermaphrodite, which means it only undergoes sexual reproduction.
FALSE
58) The number of chromosomes in a daughter cell produced by meiosis is the same as the number of chromosomes in the parent cell.
False
62) A male having an extra X chromosome (XXY) would have Turner syndrome.
False
18) The process that merges the gametes from two parents is
Fertilization
98) Which of Mendel's laws explains why the segregation of alleles for a gene on one chromosome does not influence the segregation of alleles for a gene on another chromosome?
Law of independent assortment
96) Which of Mendel's laws described the separation of two alleles during the formation of gametes?
Law of segregation
16) A diploid germ cell reduces its chromosome number by half to generate four haploid cells in
Meiosis
30) In meiosis, paired homologous chromosomes align down the center of the cell during
Metaphase I
31) In meiosis, chromosomes containing sister chromatids (not homologous chromosomes) align along the center of the cell during
Metaphase II
51) In plants, haploid gametophytes produce gametes by
Mitosis
48) Most cultivated bananas are triploid. How could these be generated from diploid parent banana plants?
Nondisjunction in meiosis followed by normal fertilization
10) A desert plant called Kalanchoe can reproduce, either with sexual reproduction through flowers, or asexually by budding off miniature leaf and root clusters from its leaves. When buds are produced, they land on the ground, take root, and grow, genetically identical to the original. If budding is used for several years, a large area may be covered with these descendents from the same original plant. The resulting population of plants will
Not be as strongly able to adapt to environmental change, compared to the Kalanchoe that are reproducing sexually
19) Mitotic cell division results in two identical cells by replicating the cell's DNA ________ and then dividing ________.
Once; once
77) Gametes contain
One set of chromosomes
90) The "P" in P generation refers to
Parental
38) A gamete having more than one complete set of paired chromosomes
Polypoid
27) In meiosis, homologous chromosomes align next to one another during
Prophase I
37) You have an opportunity in biology lab to observe the prepared, stained karyotypes of a stallion, a mare, and their foal offspring horses. Banding patterns of some of the autosomes from the foal match those of the stallion, while others from the foal match those of the mare. This variability is produced in meiosis due to
Random alignment of chromosome pairs
34) Among humans, you can observe that there is variability in shape (size), skin color, and other traits. The variety in a small population results from ________ in either sexual reproduction or meiosis.
Random fertilization & Independent Assortment
81) Mendel kept detailed records of the genetic traits of parent plants and their offspring plants. Among observations, he found that some traits were not expressed, whenever one particular allele was present. He referred to these traits as masked traits, or
Recessive traits
50) In humans, the sex of a child is determined by the
Sex chromosome in the sperm (Y chromosome from father)
9) Sexual reproduction is important to the survival of a species in a changing environment because
Sexual reproduction produces genetically variable individuals in the population
41) Why does sexual reproduction produce more genetic variability in a population than asexual reproduction?
Sexually reproducing organisms mix parental genetics in addition to crossing-over and random alignment
6) In biology lab, you are observing specimens of muscle cells and nerve cells, as examples of
Somatic cells
47) If a chromosome in one of your bone cells becomes mutated, you will not pass this mutation on to your children because
Somatic cells cannot undergo meiosis
4) An example of a haploid cell is a
Sperm cell
7) Meiosis is a process that produces
Sperm cells, egg cells, gametes, and haploid cells
