Deck 13: Genetics

Question 1

________ work with transposons was recognized when s/he received a Nobel Prize in 1983.

A) Rosalind Franklin's
B) Barbara McClintock's
C) Francis Crick's
D) Linus Pauling's
E) James Hardy's

Answer 1

B

Question 2

Changes in chromosome number and structure that ________ are important in the origin of new species (speciation).

A) are point mutations
B) create new alleles
C) affect the success of meiosis and sexual reproduction
D) interfere with mitosis
E) alter the phenotype of the individual in a somatic mutation

Answer 2

C

Question 3

The sum total of DNA in an organism's chromosomes constitutes the ________.

A) phenotype
B) genome
C) chromosome map
D) transposable genes
E) gene pool of the species

Answer 3

B

Question 4

Which is a part of DNA but not RNA?

A) uracil
B) thymine
C) adenine
D) cytosine
E) guanine

Question 5

James Watson and Francis Crick started the field of ________ with their 1953 discovery of the structure of DNA.

A) Mendelian genetics
B) transposable genetics
C) population genetics
D) genetic inheritance
E) molecular genetics

Question 6

Agents such as ultraviolet light and certain chemicals called ________ can alter DNA sequences and permanently change the genome.

A) mutagens
B) fertilization and sexual reproduction
C) chromosome addition or loss
D) mis-match of chromatids during crossing over
E) errors in replication

Question 7

Messenger RNA is a ______- stranded molecule.

A) single
B) double
C) triple
D) multiple
E) both single and double are correct

Question 8

The Central Dogma of Molecular Genetics is summarized in the following statement: ________.

A) Proteins convert the mRNA into tRNA molecules in the cytoplasm.
B) The flow of information in a cell is from DNA transcribed to mRNA in the nucleus, to the translation of mRNA into a polypeptide in the cytoplasm.
C) DNA is the template for the construction of polypeptides in the cytoplasm.
D) mRNA is transcribed into rRNA by the tRNA on ribosomes.
E) The semiconservative replication of DNA is the source of changes in the genome.

Question 9

The process of producing an accurate DNA copy of the genome is referred to as ________.

A) translation
B) PCR
C) semiconservative replication
D) transcription
E) duplicating

Question 10

If all cells of a plant have identical DNA, then why are there different cell types and tissues within a plant?

A) Different subsets of the information are used in each type of cell.
B) Internal environmental conditions may determine which subset of the genome is expressed.
C) Hormones and other growth regulators may control gene expression.
D) External environmental conditions such as light or dark may alter gene expression.
E) All of these may influence the expression of different subsets of genetic information from the genome, resulting in differentiation and development.

Question 11

Which statement about transposons is INCORRECT?

A) Transposon insertion into a gene causes a mutation that can be reversed by removal of the transposon.
B) A transposon is a small fragment of DNA that can move from one location in a chromosome to another location in the same chromosome.
C) Transposon movement often occurs when the cell is under genomic stress.
D) In nature, insertion of a transposon can be deliberately added into a harmful gene to enhance survival.
E) Molecular geneticists can use transposons to determine the function of a particular gene

Question 12

Alternate forms of the same trait (yellow seeds or green seeds) are called

A) gene factors.
B) homologous traits.
C) alleles.
D) centromeres.
E) chromosome traits.

Question 13

A sequence of nucleotides in a chromosome that controls the production of a protein is a

A) polysome.
B) gene.
C) intron.
D) chromatid.
E) operon.

Question 14

Which of the following describes the function of DNA in a cell?

A) store genetic information
B) copy genetic information for each turn of the cell cycle
C) controls the activities of the cell through gene expression
D) mutate (or change the genetic information content)
E) All of the above are functions of DNA in a cell

Question 15

________ and ________ are molecular processes that convert genetic information into functional proteins.

A) Replication; mutation
B) Meiosis; mitosis
C) Transcription; translation
D) Semiconservative; replication
E) All of these answers are correct.

Question 16

If the nucleotide sequence of DNA is T C C G A A, then the corresponding on mRNA is

A) A G G C T T
B) C T A A G G
C) A G G C U U
D) U U C G G A
E) A C C G T T

Question 17

Which statement correctly describes the arrangement of the nitrogenous bases in the double helix of DNA?

A) Each of the 4 nitrogenous bases on one DNA strand can pair with any of the other 4 nitrogenous bases on the other strand.
B) Any purine nitrogenous base on one DNA strand can pair with any other purine on the other DNA strand.
C) Any pyrimidine nitrogenous base on one strand of DNA can pair with any other pyrimidine base on the other strand.
D) Any pyrimidine nitrogenous base on one strand of DNA can pair with any purine on the other DNA strand.
E) Adenine (A), a purine, on one DNA strand pairs with thymine (T), a pyrimidine, on the other strand; Guanine (G), another purine, pairs with cytosine (C), a pyrimidine.

Question 18

An anticodon is found on a molecule of

A) mRNA.
B) tRNA.
C) rRNA.
D) DNA.
E) Both mRNA and tRNA are correct.

Question 19

________ is the study of chromosome behavior and structure at the cellular level.

A) Cytogenetics
B) Molecular genetics
C) Expression genetics
D) Transmission genetics
E) Population genetics

Question 20

Haploid and diploid chromosome sets are common in both plants and animals, but plants frequently have additional sets of chromosomes-a condition called ________.

A) point mutation
B) polyploidy
C) translocation
D) inversion
E) aneuploidy

Question 21

If red is dominant and yellow is recessive as a flower color in a certain species of plants, and if, in the same plants, long hairs are dominant and absence of hair is recessive, and a dihybrid cross involving homozygous parents is made, which of the following phenotypes would NOT appear in the F₂ generation?

A) orange, hairy
B) yellow, smooth
C) red, hairy
D) red, smooth
E) yellow, hairy

Question 22

If a pure breeding parent producing yellow seeds, the dominant phenotype, is crossed with a pure breeding parent producing green seeds, the recessive phenotype, the F₁ generation will produce

A) 100% yellow seeds.
B) 50% yellow seeds; 50% green seeds.
C) 75% yellow seeds; 25% green seeds.
D) 75% green seeds; 25% yellow seeds.
E) not enough information given.

Question 23

A single pair of genes controls red versus blue flower color in larkspurs, and red is dominant phenotype. Which of the following phenotypes should occur in the F₃ generation if the parental generation was pure breeding strains for red and blue phenotypes ?

A) all blue
B) all purple
C) red and blue
D) red, purple, and blue
E) all red

Question 24

In a cross between a long and a globe-shaped radish, the F₁ generation consisted of 247 oval-shaped radishes. The F₂ generation consisted of 62 long radishes, 127 oval radishes, and 59 globe-shaped radishes. Which of the following pertaining to this cross is true?

A) long is dominant
B) oval is dominant
C) globe-shaped is dominant
D) oval is recessive
E) None of the shapes is recessive.

Question 25

In a variety of cornflowers in which blue flowers and dwarf plants are controlled by dominant genes carried on separate pairs of chromosomes, and white flowers and tall plants are their recessive counterparts, assume a cross has been made between a homozygous blue, dwarf plant and a homozygous white, tall plant. Which of the following would be represented in the F₁ generation?

A) BBDD
B) BBdd
C) bbDD
D) BbDd
E) BbDD

Question 26

When Mendel crossed tall pea plants with short ones, all of the offspring were intermediate in height.

Question 27

Assume the same cross as in question 24. If the F₂ generation involves thousands of individual plants that are carefully counted, and four different phenotypes in a ratio other than 9:3:3:1 are noted, which of the following would be suspected?

A) absence of dominance
B) linkage
C) leakage of color
D) no crossing-over had occurred
E) genes were not involved in the cross

Question 28

Assume the same cross as in question 29. Which of the following phenotypic ratios would be represented in the F₂ generation?

A) 1:1:1:1
B) 3:1
C) 1:2:1:2:2:4:1:2:1
D) 9:3:3:1
E) No ratio, because all the phenotypes are identical.

Question 29

The most significant cause for exceptions to the Hardy-Weinberg law is

A) protoplast fusion.
B) selection.
C) polyploidy.
D) the proportion of dominant genes to recessive genes.
E) random breeding.

Question 30

If the cross BbDD x bbDd is made, which of the following would NOT be represented in the offspring?

A) BbDD
B) BbDd
C) bbDD
D) bbDd
E) BBDd

Question 31

Mendel discovered the rules of inheritance only after the discoveries of chromosomes and meiosis.

Question 32

What is the correct genotype of a homozygous dihybrid individual having dominant phenotypes for both traits?

A) TTXx
B) ttXx
C) TTXX
D) TtXx
E) ttXX

Question 33

Which of the following is NOT known for the pioneer experiments and theories that led to the development of the science of genetics?

A) Linnaeus
B) Correns
C) Mendel
D) de Vries
E) Morgan

Question 34

Which is a heterozygous genotype for a given trait?

A) YY
B) Yy
C) WX
D) yy
E) none of these answers are correct

Question 35

Which of the following increases the probability of genes being inherited together?

A) closeness to each other on a chromosome
B) length of the chromosome
C) size of the spindle during meiosis
D) low number of chromosomes
E) high number of chromosomes

Question 36

In sweet peas, purple flower color and oblong pollen grains are dominant, with the recessives being red flower color and spherical pollen grains. When a homozygous purple, oblong plant is crossed with a homozygous red, spherical plant, the F₁ generation consists entirely of purple, oblong plants. When an F₁ plant is crossed with a homozygous red, spherical plant, the offspring are produced in a ratio of 7 purple, oblong to 1 purple, spherical to 1 red, oblong to 7 red, spherical. Which of the following is the only plausible explanation for such results?

A) hybridization has occurred
B) linkage is involved
C) the plants received too much fertilizer
D) bad sex cells are involved
E) the plants resent scientists messing with their genes

Question 37

Chromosomal mapping primarily involves

A) drawing diagrams of chromosomes to show their relative lengths.
B) photographing chromosomes.
C) cutting and pasting chromosome pictures together.
D) studying prophase II chromosomes in squashed cells.
E) calculating crossover percentages.

Question 38

The British biologists who first reported linkage in sweet peas were

A) T. H. Morgan and M. G. Morgan.
B) G. H. Hardy and W. Weinberg.
C) H. de Vries and C. Correns.
D) W. Bateson and R. C. Punnett.
E) N. Borlaug and K. T. Borlaug.

Question 39

Assume the same cross as in question 29. How many different kinds of genotypes would occur in the F₂ generation?

A) 16
B) 8
C) 9
D) 12
E) 1 (i.e., all the genotypes are identical)

Question 40

Since Mendel's time, types of inheritance that don't follow Mendel's rules have been discovered. Which of the following situations is NOT an exception to Mendel's rules?

A) A phenotype in the offspring is intermediate between the two parental phenotypes.
B) Phenotypes of the offspring show range of phenotypes rather that two distinct phenotypes.
C) When doing a dihybrid cross between two heterozygous F₁ offspring, the ratio obtained is statistically different from the Mendelian ratio.
D) When an individual with a heterozygous phenotype for a trait is crossed with an individual with a homozygous recessive phenotype, the ratio of phenotypes of the offspring is 1:1.
E) Two or more gene pairs are involved in producing the phenotypes of a given trait.

Question 41

A recessive factor is one that cannot manifest itself in the phenotype.

Question 42

Bateson and Punnett could not adequately explain unusual genetic ratios that occurred as a result of linkage.

Question 43

The law of independent assortment is illustrated only in monohybrid crosses.

Question 44

Lack of dominance means that only recessive genes are present.

Question 45

Mendel's law of unit characters says that the inheritance of characteristics is controlled by factors that always occur in pairs.

Question 46

Messenger RNA is a small molecule composed of a few nucleotides.

Question 47

A tRNA molecule relays amino acids in response to a specific "blueprint" coded by the DNA.

Question 48

A tRNA molecule can fit into a slot in a ribosomal subunit.

Question 49

The Hardy-Weinberg law addresses itself to proportions of genes in a normally interbreeding population.

Question 50

The pinpointing of relative locations of genes on chromosomes CANNOT be brought about by calculating percentages of crossing-over in large populations.

Question 51

The genetic information encoded in DNA is difficult to alter, making mutations rare.

Question 52

A backcross is one in which both parents are homozygous.