Deck 10: Foundations of Genetics

Question 1

The diploid number of chromosomes in humans is 46.The haploid number is

A) 138.
B) 92.
C) 46.
D) 23.

Answer 1

D

Question 2

In Japanese four o'clock flowers,pink-flowered plants are produced when red-flowered plants are crossed with white-flowered plants.This type of inheritance can best be described as

A) simple dominant and recessive traits.
B) codominance.
C) incomplete dominance.
D) sex-linked traits.

Answer 2

C

Question 3

The degree of earlobe attachment in humans is inherited as a simple dominant allele of free earlobes,or as a recessive allele of attached earlobes.What is the probability that a woman with attached earlobes will have children with attached earlobes if their father has free earlobes,but his father had attached earlobes?

A) 1 in 2
B) 3 in 4
C) 1 in 10
D) none

Answer 3

A

Question 4

If several traits are affected by the same allele,the allele is said to be

A) recessive.
B) dominant.
C) epistatic.
D) pleiotropic.

Question 5

Human height shows a continuous variation from the very short to the very tall.Height is most likely controlled by

A) a single gene.
B) sex-linked genes.
C) the environment.
D) multiple genes.

Question 6

In the human ABO blood grouping,there are four basic blood types,type A,type B,type AB,and type O.The blood proteins A and B are

A) simple dominant and recessive traits.
B) codominant.
C) incompletely dominant.
D) sex-linked traits.

Question 7

What discovery by T.H.Morgan finally determined that genes were carried on chromosomes?

A) Heat-sensitivity of certain enzymes determining coat color
B) Sex-linked eye color in fruit flies
C) The finding of complete dominance
D) Discovery of the Rh blood group

Question 8

Two true-breeding pea plants are crossed,one with purple flowers and the other with white.Their offspring are

A) heterozygous with the dominant phenotype.
B) homozygous with the recessive phenotype.
C) a mixture of purple and white flowers with varying genotypes.
D) still true-breeding,with the same parental genotypes.

Question 9

Gregor Mendel's work was different from that of other researchers working on inheritance in his day because he alone

A) was a religious man.
B) worked with pea plants.
C) knew how to grow plants.
D) actually counted the numbers and types of offspring.

Question 10

Hemophilia is a group of different inherited blood-clotting disorders.Which is true about hemophilia?

A) It causes sterility
B) It is more common in females than in males
C) It is more common in males than in females
D) It is inherited only on the autosomes

Question 11

Humans who have lost one copy of an autosome are called ____________ and generally do not survive development.

A) monosomics
B) trisomics
C) eusomics
D) diploids

Question 12

Foxes,cats,and rabbits have enzymes that are heat-sensitive,causing a seasonal variation in coat color due to

A) an environmental effect.
B) multiple alleles.
C) pleiotropy.
D) incomplete dominance.

Question 13

Tall is dominant to dwarf in pea plants.If two dwarf pea plants were crossed,their offspring will be

A) all tall plants.
B) all dwarf plants.
C) half tall,half dwarf plants.
D) plants of an intermediate height.

Question 14

What is the probability of getting a pea plant with recessive green seed color when two heterozygous pea plants,both having the dominant yellow-seeded phenotype,are crossed with each other?

A) 1 in 6
B) 1 in 4
C) About half
D) None

Question 15

Down syndrome in humans is due to

A) monosomy (one copy of chromosome #21).
B) two Y chromosomes.
C) three copies of chromosome #21.
D) three X chromosomes.

Question 16

Red-green colorblindness is a sex-linked trait.A woman with normal color vision,whose father was colorblind,mates with a colorblind man.What chance do each of their sons have of being colorblind?

A) 50% chance
B) 100% chance
C) 0% chance
D) 10% chance

Question 17

Genes for sex-linked traits tend to be carried on what chromosomes?

A) Chromosome 21
B) Any of the autosomes
C) Y chromosomes
D) X chromosomes
E) Chromosome 13

Question 18

The offspring of the P generation are referred to as the

A) true recessives.
B) test cross.
C) F₁ generation.
D) F₂ generation.

Question 19

Mendel tested for heterozygotes by using a

A) dihybrid cross.
B) testcross.
C) monohybrid cross.
D) true-breeding cross.

Question 20

Which of the following analyses is not used in genetic screening of fetal cells?

A) genetic markers
B) testcross results
C) enzyme activity
D) karyotyping

Question 21

Mendel's "factors" for inheritance are now known to be ________.

Question 22

A central role for chromosomes in heredity was first suggested by

A) Karl Correns.
B) Gregor Mendel.
C) Thomas Hunt Morgan.
D) Walter Sutton.

Question 23

Which of the following crosses represents a dihybrid cross?

A) RRrr x DdDd
B) RR x Dd
C) RrDd x RRdd
D) RD x Rd
E) Rd x RR

Question 24

Where are genes located in the cell?

A) on chromosomes
B) on the endoplasmic reticulum
C) in the Golgi complex
D) within the cytoplasm
E) on the plasma membrane

Question 25

White flower color is recessive to purple.What is the genotypic ratio when two heterozygous pea plants are crossed?

A) 3: 1
B) 4: 0
C) 1: 2: 1
D) 3: 1
E) 1: 1: 1

Question 26

Mendel's law that states only one allele specifying an alternative trait can be carried in a particular gamete is called the _________________________________.

Question 27

There are 3 alleles that lead to the ABO blood types.How many alleles does an individual inherit from their parents?

A) 1
B) 2
C) 3
D) 4
E) None of the choices is correct.

Question 28

An individual is said to be _____________ if it has two copies of the same factor for a given trait.

Question 29

Genes are made of

A) ribosomes.
B) cytoplasm.
C) protein.
D) DNA.
E) lipids.

Question 30

Whose work with fruit flies presented the first clear evidence that the genes determining Mendelian traits reside on chromosomes?

A) Karl Correns
B) Gregor Mendel
C) Thomas Hunt Morgan
D) Walter Sutton

Question 31

White flower color is recessive to purple.What is the genotypic ratio when two heterozygous pea plants are crossed?

A) 3: 1
B) 4: 0
C) 1: 2: 1
D) 3: 1
E) 1: 1: 1

Question 32

A dominant human genetic disorder that does not reveal itself until middle age is _______________.

Question 33

Which of the following represents a test cross?

A) Tt x tt
B) TT x Tt
C) Tt x Tt
D) tt x tt
E) TT x TT

Question 34

The closer two genes are to each other on a chromosome,the more likely they are to segregate independently.

Question 35

Which of the following statements about how genotype determines phenotype is correct?

A) Proteins determine the sequence of genes.
B) Amino acids are located on chromosomes and determine what genes will be expressed.
C) Associations of proteins form polypeptides,which contain genes.
D) Genes encode a sequence of amino acids for a particular polypeptide or protein.
E) Genes are located on proteins,which encode a sequence of amino acids.

Question 36

Which of the following is a sex-linked disorder?

A) Cystic fibrosis
B) Duchenne muscular dystrophy
C) Huntington's disease
D) Tay-Sachs disease
E) Hypercholesterolemia

Question 37

Nondisjunction of chromosomes resulting in aneuploidy occurs during

A) anaphase of mitosis.
B) prophase I.
C) metaphase II.
D) anaphase I or II.
E) telophase I.

Question 38

The outward expression of an organism's genotype is referred to as its genotype.

Question 39

A ______________ is a DNA molecule that contains about 1000 genes and has proteins to help it retain its shape.

Question 40

The ability to taste PTC is a dominant trait.If a heterozygote woman has a child with a man who is not a taster,what is the chance their child will be a taster?

A) 100%
B) 75%
C) 50%
D) 25%
E) 0%

Question 41

What is the possible advantage of being heterozygous for the sickle-cell gene?

Question 42

A genetic family tree can more correctly be called a ____________.

Question 43

Mendel's Law of Independent Assortment states that genes located on different chromosomes are inherited independently of one another.If this is the case,what happens when two genes are located on the same chromosome: are they inherited together,do they separate,or both?

Question 44

What is the evolutionary significance of mutation?

Question 45

If a white-flowered pea plant (ww)is crossed with a heterozygous purple-flowered plant (Ww),what will their offspring look like?

Question 46

______________ effects occur when a single allele has more than one effect on the phenotype.

Question 47

When a gene is carried on one of the sex chromosomes,it is said to be __________________.

Question 48

A woman with blood type B has a baby with blood type O.A man she says is the baby's father has blood type A,but he denies having fathered the child.Could he be the father?

Question 49

When homologous chromosomes or chromatids fail to separate properly in meiosis,this is called _________________.