Allele -An alternate form of a gene for one trait

  1. Asexual reproduction - Reproduction that requires only one parent – mitosis only
  2. Autosomal______

______

  1. Birth defect- an inherited anomaly that affects the functioning of an offspring
  2. Chromosome - Long pieces of DNA found in the center (nucleus) of eukaryotic cells
  3. Co-dominance______

______

  1. Cross ______
  2. Crossing over ______

______

  1. Dihybrid - identically heterozygous at two loci for example: RrYy
  2. Diploid - A set of chromosomes containing both members of each chromosome pair
  3. Dominant - a trait that is observed even if only one allele is present
  4. Egg - A female gamete with one copy of each chromosome
  5. Embryo - Early stages of growth and differentiation characterized by rapid cell division and the formation of organ systems
  6. Enzyme______
  7. Fertilization - A male and female gamete fuses
  8. Gamete______
  9. Gene - A segment of DNA that codes for a particular trait
  10. Genetic variation ______

______

  1. Genome ______
  2. Genotype - genetic makeup of an organism
  3. Haploid - A set of chromosomes containing only one member of each chromosome pair
  4. Heredity______
  5. Heterozygous - organisms that have different alleles for a particular trait
  6. Homozygous organisms that have identical alleles for a particular trait______
  7. Homologous______

______

  1. Hybrid______

______

  1. Incomplete dominance______

______

  1. Meiosis______
  2. Mitosis______
  3. Monohybrid______
  4. Multicellular organism______
  5. Non-disjunction______

______

  1. Ovule______
  2. Offspring______
  3. Pedigree______
  4. Phenotype- physical appearance of an organism______
  5. Probability______
  6. Punnett Square ______
  7. Recessive- a trait that requires both alleles to be observed______
  8. Recombinant ______

______

  1. Replication ______
  2. Segregation______
  3. Sexual reproduction - Reproduction that requires two parents
  4. Sex-linked______

______

  1. Somatic cell______
  2. Sperm - A male gamete with one copy of each chromosome______
  3. Trait ______
  4. X chromosome ______
  5. Y chromosome ______
  6. Zygote ______
  7. Hemophilic ______
  8. Inheritance ______
  9. Mendel ______

Diagram and labeleachstages of mitosis prior to cytokinesis

Diagram and label eachstages of meiosis

Genetics Unit Study Guide – HeredityKEY

1.One step in a single eukaryotic cell becoming two daughter cells is the process of mitosis.

2.The principle that describes that genes segregate without influence on each others inheritance: Independent assortment

3.If an organism has a gamete containing 12 chromosomes, one would expect each of its body cells to contain 24 chromosomes.

4.Compared to the number of chromosomes contained in a body cell of a parent, how many chromosomes would normally be contained in a gamete?1/2, one-half as many

5.The numbers in the figure represent the chromosome number found in each of the dog cells shown. The processes that are occurring at A and B are A=Meiosis and B=fertilization.

6.Which chromosomes shown in the picture above are homologous to each other? A and C

7.During the formation of gametes, independent assortment occurs between homologous chromosomes

8.Mendel’s hypothesis that two factors for each trait are segregated during the formation of gametes is explained by separation of homologous chromosomes during meiosis.

9.If a corn plant has a genotype of Ttyy, what are the possible genetic combinations that could be present in a gamete (single grain of pollen) from this plant? Ty or ty

10.The law of independent assortment states that gene pairs sort randomly and independently of each other.

11.The law of segregation states that alleles of a gene separate from each other during meiosis.

12.To describe how traits can disappear and reappear in a certain pattern from generation to generation, Mendel proposed the Law of Independent Assortment.

13.One of the plants that the scientist is studying has an extra copy of one chromosome in all its cells. This variation most likely occurred during Meiosis

14.Crossing-over most commonly results in new combinations of genes

BR / Br / bR / Br
BR / BBRR / BBRr / BbRR / BbRr
Br / BBRr / BBrr / BbRr / Y
bR / BbRR / BbRr / X
Br / BbRr / Bbrr

A male guinea pig with black, rough hair (BbRr) was crossed with a female guinea pig with black, rough hair (BbRr). The Punnett square contains the partial results from this mating. (B=black, b=white, R=rough, r=smooth)

15.According to the figure above, what is the genotype for X? bbRR and for Y? BBrr

16.Using the diagram above, explain the pattern of inheritance for hemophilia (a blood disease) trait. The allele for hemophilia is carried on the X chromosome.

17.Above is a pedigree for the recessive trait, attached ears (aa). The dominant trait is unattached ears (A). The black circles indicate people who have the recessive trait.

Using the chart, what would be the genotype of person I,2? Aa

Using the chart, what would be the genotype of person II,2? Aa

XH / Xh
h = hemophiliac / Xh / XHXh / XhXh
H = normal / Y / XHY / 4

18.Using the chart above, how many offspring will be hemophiliacs? 2/4

19.The phenotype of box 4 is XhY = hemophiliac male

20.In fruit flies, the gene for red eyes (R) is dominant and the gene for sepia eyes (r) is recessive. What are the possible combinations of genes in the offspring of two red-eyed heterozygous flies (Rr)?

Rr x Rr / R / r
R / RR / Rr / 1/4 RR, 2/4 Rr, 1/4 rr
r / Rr / rr

21.The appearance of an organism is its phenotype

22.To determine the genotype of an individual that shows the dominant phenotype, you would cross that individual with one that is homozygous recessive

23.In a two-factor cross between an individual with the genotype RRYY and an individual with the genotype rryy, all of the offspring will have the genotype RrYy

24.A segment of DNA that controls a particular hereditary trait is called a gene

25.The genetic makeup of an organism is called its genotype

26.Having two similar, dominant alleles for a trait is called homozygous dominant

27.A cross between two plants that have pink flowers produced plants that have red, pink, or white flowers. What is the most likely explanation for these results? Inheritance involving incomplete dominance.

28.An organism in which two alleles for a trait are different is heterozygous

29.The phenotype of an organism is the appearance of an organism reflecting all the traits that are actually expressed.

30.Tallness (T) is dominant to shortness (t) in pea plants. What is the genotype of a pea plant that is heterozygous for tallness? Tt

31.An individual heterozygous (Tt) for a trait and an individual homozygous recessive (tt) for the trait are crossed and produce offspring that are of two different phenotypes.

Tt x tt / T / t
t / Tt / tt
t / Tt / tt

32.A scientist crossed a tall pea plant with a short pea plant. All of the four hundred offspring produced were tall pea plants. Explain these results. TT x tt indicating that the allele for tall plants is dominant.

33.A family has eight children. Six children have second toes that are longer than the big toe. Two children have second toes that are shorter than the big toe. What are the most likely genotypes of the parents? Ratio of 3 long to 1short indicates typical phenotypic ratios that result from two heterozygous parents: Ll and Ll

34.A homozygous individual would have what possible genotype? Two dominant alleles or Two recessive alleles.

35.If two parents with dominant phenotypes produce an offspring with a recessive phenotype, what can you say about the parents? The parents were both heterozygous

36.In a monohybrid cross between two heterozygous parents, one would expect the offspring to be 1 DD: 2 Dd : 1dd

37.Living things grow because organisms produce more and more cells by mitosis.

38.How are mature human sperm and eggs similar? They have the same number of chromosomes in the nuclei.

39.Female gametes are called eggs.

40.Each egg and sperm cell contains a haploid number of chromosomes. After fertilization, a zygote is formed have a diploid number of chromosomes.

41.How many chromosomes are there in a human gamete?23

42.A human zygote contains 46chromosomes, fifty percent of the total coming from each parent cell.

43.Sex cells are also called gametes

44.A fertilized egg is also called a(n) zygote

45.Which diagram correctly illustrates the fusion of normal gametes that will most likely produce a human male? Picture 4 showing a male sperm and a female egg.

46.A developing heart increases in size through the process of Mitosis

47.A man with a certain syndrome marries a woman who is normal for that trait. They have 6 children, three girls and three boys. All four the girls have the same syndrome as the father whereas none of the boys is affected. Which type of heredity is not possible here?Y-linked

48.Nondisjunction is related to a number of serious human disorders. How does nondisjunction cause these disorders?Alters the chromome number

49.What occurs during the process of meiosis in humans that can lead to a child with the condition of Down Syndrome? Production of gametes with one duplicate chromosome. Nondisjunction of chromosome 21 occurs during meiosis.

50.What is the name for this process and what causes it? Nondisjuction due to improper segregation of chromosomes.

51.A white mouse whose parents are both white produces only brown offspring when mated with a brown mouse. The white mouse is most probably homozygous recessive.

52.Given that the dominance hierarchy of rabbit fur color alleles is C>Cch>Ch, from grey to chinchilla to Himalayan, respectively what would be the percentage of Himalayan colored rabbits from parents with CCh and CchCh?

C Ch x Cch Ch / C / Ch
Cch / C Cch / Cch Ch / 1/4 CCch, 1/4 CCh, 1/4 CchCh, 1/4 ChCh
Ch / C Ch / Ch Ch / ¼ = 25% ChCh = Himalayan colored

53.The diagram shows a diploid cell with two homologous pairs of chromosomes. Due to independent assortment, the possible allelic combinations that could be found in gametes produced by the meiotic division of this cell are Bd, BD, bd, bD

54.Using the figure below, which process would result in the formation of chromosome C from chromosomes A and B?Crossing Over

55.Suppose an animal is heterozygous AaBb, and the traits are not linked. When meiosis occurs, list out the possible combinations of gametes that can be made for these traits?

4 possible combinations AB, Ab, aB, and ab

56.Suppose an animal is heterozygous AaBbCc, and the traits are not linked. When meiosis occurs, list out the total possible combinations of gametes that can be made for these traits? 8 possible combinations: ABC AbC aBC abC

ABcAbcaBcabc

57.A true-breeding tall pea plant is crossed with a true-breeding short pea plant, and all the offspring are tall. What is the most likely genotype of the offspring assuming a single-gene trait?

1) TT x tt = Tt / T / T
t / Tt / Tt / 4/4 Tt
t / Tt / Tt

58.In mice, black is dominant to white color and color is determined by a single gene. Two black mice are crossed. They produce 2 black offspring and one white offspring. If the white offspring is crossed with one of its parents, what percent of the offspring are expected to be white?

1) Parents must be heterozygous if one white is / B / b
produced from two black parents (Bb x Bb) / b / Bb / bb / 2/4 bb
2) Bb x bb / b / Bb / bb / 50% white

59.Mendel crossed a true-breeding plant that produced green seeds with a true-breeding plant that produced yellow seeds to produce an F1 generation. The entire F1 generation produced yellow seeds. Then he crossed the F1 offspring with each other to produce the F2 generation. From the F2 generation, he counted 6022 yellow seeds.What is an estimate of the number of green seeds he collected from the F2 generation?

Yellow is dominant / F2 / Y / y / 75% Yellow (YY,Yy); 25% Green (yy)
1) YY x yy = Yy (F1) / Y / YY / Yy / (0.75)(x) =6,022; x = 8,030 total seeds
2) Yy x Yy = (F2) / y / Yy / yy / (8,030)(0.25) = 2,008 green seeds estimate

60.In which situation are the phenotypes of F2 offspring expected to follow the ratio of 9:3:3:1.

A dihybrid cross for two unlinked traits

61.If two heterozygous individuals are crossed, what percent of their offspring are also expected to be heterozygous

Hh x Hh / H / h
H = dominant / H / HH / Hh / 2/4 Hh = 50%
H = recessive / h / Hh / hh

62.A geneticist crossed fruit flies to determine whether two traits are linked. The geneticist crossed a fly with blistery wings and spineless bristles (bbss) with a heterozygous fly that had normal wings and normal bristles (BbSs). Which results in the next generation would suggest these traits are linked?

If unlinked / wings/bristles / If linked / wings/bristles
bs / bs / bs / bs / 4BbSs - normal/normal / bs / bs / 50% normal/normal
BS / BbSs / BbSs / BbSs / BbSs / 4Bbss - normal/ spineless / BS / BbSs / BbSs / 50% blistery /spineless
Bs / Bbss / Bbss / Bbss / Bbss / 4 bbSs - blistery /normal / bs / bbss / bbss / 50% of each kind
bS / bbSs / bbSs / bbSs / bbSs / 4 bbss –blistery /spineless / Recall that crossing over can occur resulting in rare instances of other combination
bs / bbss / bbss / bbss / bbss / 25% of each kind

63.A man heterozygous for blood type A marries a woman heterozygous for blood type B. The chance that their first child will have type O blood is ____.

To have a type o child / A / o / Each offspring born will
Parents must be heterozygous / B / BA / Bo / have a 25% change of being oo,
Ao x Bo / o / Ao / oo / with Type O blood

64.According to figure below, what is the chance that individual A will be afflicted with Huntington's?

Autosomal / D / d / Circle = female; square = male
D = Disease; d = normal / d / Dd / dd / ½ = 50% chance w/ disease
With one child affected dad has / d / Dd / dd
to be a carrier (Dd)

65.Consider the cell labeled X in the figure below containing 4 chromosomes. Which of the four cells below it represents a healthy gamete that could be produced from this cell?

A because it has a chromosome from each homologous chromosome pair

66.What is the best description of the events that take place during anaphase II?

Sister chromatids are separated and pulled to opposite sides of the cell

67.During which phase of meiosis do homologous pairs of chromosomes line up next to one another along the equator?Metaphase I

Metaphase I is then followed by Anaphase I when homologous chromosomes travel to opposites sites of the cell reducing the chromosome number from 2n to n

68.Which stage of meiosis is responsible for the law of independent assortment?

Metaphase I

70. What fraction of this cross will be recessive for both traits?Parent gametes must both be recessive mx which only occurs in 1 of sixteen possiblilities, so the fraction is 1/16.

71. If individual III-2 marries a person with the same genotype as individual I-1, what is the chance that one of their children will be afflicted with hemophilia?

The chance is 0% for children to be afflicted = exhibit the disease; However, there is a 50% that one of their children may be a carrier (1/2 shaded)

72. What type of inheritance pattern does the trait represented by the shaded symbols illustrate?Sex-linked carriers

73. For the trait being followed in the pedigree, individuals II-1 and II-4 can be classified as carriers.

74. What is the relationship between individual I-1 and individual III-2? Grandmother (I-1) and Grandson (III-2)

75. The coat color in Labrador retrievers is controlled by two sets of alleles that interact epistatically. The gene E/e determines whether the fur has pigment or not and is epistatically dominant to the gene B/b, which controls the darkness of pigment when it is there. A breeder crosses a purebred black Lab, with the genotype BBEE, and a purebred yellow Lab with the genotype bbee, producing offspring that are black. A test cross is done between these offspring and an individual with the genotype bbee. What is the expected ratio of black:chocolate:yellow?

Cross 1) BBEE x bbee = BbEe / BE / Be / bE / be / 4/16 = ¼ BbEe = black
BbEe = Black / be / BbEe / Bbee / bbEe / bbee / 4/16 = ¼ Bbee = black not dark
Cross 2) BbEe x bbee / be / BbEe / Bbee / bbEe / bbee / 4/16 = ¼ bbEe = yellow
be / BbEe / Bbee / bbEe / bbee / 4/16 = ¼ bbee = yellow
Note: Bbee = cholate / be / BbEe / Bbee / bbEe / bbee / 1 Black: 1 Chocolate: 2 Yellow

76. One step in a single eukaryotic cell becoming two daughter cells is the process ofmitosis.

77. How are mature human sperm and eggs similar?

They both have the same number of chromosomes in their nuclei.

Genetics – Heredity Unit Overview KEY1