Biology 111 Exam 1 Key

Exam I

TEST FORM:  B

Biology 110 – Fall 2014

Dr. David H. Bos

INSTRUCTIONS:  There are 35 questions on this exam.  No calculators, cell phones, or other electronic devices are allowed.  Read each question carefully.  There is only one correct answer for each question. Choose the best answer.  Do not fill in multiple answers.  Turn in only the scantron sheet.   Keep the exam.  Take your time, think and good luck!

1. A cell starts with 40 chromosomes (20 homologous pairs).  After DNA replication how many chromosomes does the cell have?

1. 20 (10 homologous pairs)
2. 40 (20 homologous pairs)
3. 80 (40 homologous pairs)
4. 40 but no homologous pairs of chromosomes—each is unique
5. 80 but no homologous pairs of chromosomes—each is unique

1. Which process describes cell division in prokaryotic organisms?

1. Mitosis
2. Meiosis
3. Binary fission
4. Cytokinesis
5. Telekinesis

1. What is the term used to describe about 150 nucleotides of DNA wrapped around a core of histone proteins?

1. 30-nm fiber
2. Chromosome
3. Nucleosome
4. Centrosome
5. Centromere

1. Meiotic cell division plays a key role in which biological processes?

1. Reproduction of bacteria
2. Growth and development of eukaryotic organisms
3. Wound healing
4. Responses to environmental changes
5. Sexual reproduction

1. During the G1 phase of the cell cycle, most of the DNA would be in what state of compaction?

1. Loose (double helix)
2. Nucleosome
3. Centrosome
4. Chromosome
5. 30-nm fiber

1. During telophase of mitosis, how many DNA double helices make up a single chromosome?

1. One
2. Two
3. Four
4. Eight
5. Just two but they are substantially different from one another

1. Which of the following is true regarding chromosomes during different forms of cell division?

1. The pairing of homologous chromosomes occurs in prophase of mitosis and not in meiosis
2. Homologous chromosomes aren’t present in the same cell at the same time during mitosis
3. The pairing of homologous chromosomes occurs in prophase II of meiosis and not in mitosis
4. Homologous chromosomes are more similar to each other than sister chromatids during all phases of mitosis
5. None of the above are true

1. Catenins are proteins that link one cell to another into unified tissues.  Loss of function mutations to catenins cause loss of contact inhibition.  Normally functioning catenins are best categorized as what type of protein?

1. Histones
2. Proto-oncogenes
3. Tumor suppressor genes
4. oncogenes  
5. Cyclin

1. During which phase of the cell cycle does the nuclear envelope reassemble?

1. S phase
2. G1
3. Telophase
4. Prophase
5. G0

1. Disruption of the signaling of growth factors will directly affect which of the cell cycle check points?

1. G1
2. G2
3. Anaphase
4. Telophase checkpoint
5. None of the checkpoints

1. Which of the following conditions is required to proceed from metaphase to anaphase?

1. Cdc 20 is inactive
2. Securin is active
3. APC is inactive
4. Cohesion is active (intact)
5. Separase is active

1. Which two processes are most similar compared to each other?

1. Binary fission and meiosis II
2. Meiosis II and mitosis
3. Meiosis I and mitosis
4. Mitosis and binary fission
5. Meiosis I and binary fission

1. A cell starts with 40 chromosomes (20 homologous pairs).  After meiosis I what is the arrangement of chromosomes in each cell?

1. 20 chromosomes; each with two identical chromatids
2. 20 chromosomes; each with one chromatid
3. 20 chromosomes; each with two nonidentical chromatids
4. 40 chromosomes; each with one chromatid
5. 40 chromosomes; each with two nonidentical chromatids

1. Flower position is a trait inherited in true Mendelian fashion; A = axial, a = terminal.  What is the genotype of a pea plant with axial flowers if a test cross with that pea plant yields offspring, all of which have axial flowers?

1. AA
2. Aa
3. aa
4. any of the above
5. none of the above

1. At what point of cell division are the nuclei of cells undergoing meiosis first considered haploid nuclei?

1. After meiosis II and cytokinesis
2. After DNA replication
3. After anaphase of meiosis II
4. After telophase of meiosis I
5. After crossing over in meiosis I

1. A toxin that prevented the formation of vesicles inside of a cell would most disrupt which process?

1. Cytokinesis in bacteria and plants
2. Cytokinesis in bacteria
3. Cytokinesis in animals and plants
4. Cytokinesis in plants
5. Cytokinesis in animals

1.  What do we mean when we use the terms monohybrid cross and dihybrid cross?

1. A monohybrid cross involves a single parent, whereas a dihybrid cross involves two parents
2. A monohybrid cross produces a single progeny, whereas a dihybrid cross produces two progeny
3. A dihybrid cross involves organisms that are heterozygous for two characters, and a monohybrid cross involves only one
4. A monohybrid cross is performed for one generation, whereas a dihybrid cross is performed for two generations
5. A monohybrid cross results in a 9:3:3:1 ratio, whereas a dihybrid cross gives a 3:1 ratio

1. What was the most significant conclusion that Gregor Mendel drew from his experiments with pea plants?

1. There is considerable genetic variation in garden peas
2. Traits are inherited in discrete units, and are not the results of "blending"
3. Recessive genes occur more frequently in the F1 generation than do dominant ones
4. Genes are composed of DNA
5. An organism that is homozygous for many recessive traits is at a disadvantage

1. Which of the following differentiates between independent assortment and segregation?

1. The law of independent assortment requires describing two or more genes relative to one another
2. The law of segregation requires describing two or more genes relative to one another
3. The law of segregation requires having two or more generations to describe
4. The law of independent assortment is accounted for by observations of prophase I
5. The law of segregation is accounted for by anaphase of mitosis

1. Two plants are crossed, resulting in offspring with a 3:1 ratio for a particular trait. What does this suggest?

1. that the parents were true-breeding for contrasting traits
2. that the trait shows incomplete dominance
3. that a blending of traits has occurred
4. that the parents were both heterozygous for a single trait
5. that each offspring has the same alleles for each of two traits

1. Males are more often affected by sex-linked traits than females because

1. male hormones such as testosterone often alter the effects of mutations on the X chromosome
2. female hormones such as estrogen often compensate for the effects of mutations on the X chromosome
3. X chromosomes in males generally have more mutations than X chromosomes in females
4. males are hemizygous for the X chromosome
5. mutations on the Y chromosome often worsen the effects of X-linked mutations

1. What is the probability of the genotype aaBBcc appearing in the offspring a Mendelian cross of parents with the genotypes aaBbCc x aaBbcc?

1. 1/2
2. 1/64
3. 1/4
4. 1/8
5. 1/16

1. In cattle, roan coat color (mixed red and white hairs) occurs in the heterozygous (Rr) offspring of red (RR) and white (rr) homozygotes. Which of the following crosses would produce offspring in the ratio of 1 red:2 roan:1 white?

1. red × white
2. roan × roan
3. white × roan
4. red × roan
5. The answer cannot be determined from the information provided

1. Cystic fibrosis results from a single gene mutation and affects the lungs, the pancreas, the digestive system, and other organs, resulting in symptoms ranging from breathing difficulties to recurrent infections. Which of the following terms best describes this?

1. incomplete dominance
2. multiple alleles
3. pleiotropy
4. epistasis
5. codominance

1. A woman who has blood type A has a daughter who is type O and a son who is type B.

 Which of the following is a possible partial genotype for the son?

1. IBIB
2. IBIA
3. ii
4. IBi
5. IAIA

1. When Thomas Hunt Morgan crossed his red-eyed F1 generation flies to each other, the F2 generation included both red- and white-eyed flies. Remarkably, all the white-eyed flies were male. What was the explanation for this result?

1. The gene involved is on the Y chromosome
2. The gene involved is on the X chromosome
3. The gene involved is on an autosome, but only in males
4. Other male-specific factors influence eye color in flies
5. Other female-specific factors influence eye color in flies

Use the following information to answer Questions 27 - 29: