POB Lab Unit 3

Justin has type A blood and his wife Brittany has type B blood. Justin's parents both have type AB blood, and Brittany's parents also both have type AB blood. What are the chances that Justin and Brittany's biological son Theodore has type A blood?

0%

In a situation in which genes assort independently, what is the ratio of the gametes produced by an AaBB individual?

1 AB : 1 aB

Which of the following statements regarding sickle-cell disease is false?

Sickle-cell disease causes white blood cells to be sickle-shaped.

Which of the following is the best choice of null hypothesis for the first lab exercise?

There will be no significant difference between predicted and observed phenotypes.

It necessary for the nuclei to go through 2 sets of divisions in meiosis because it is necessary for homologous pairs of chromosomes to separate in the first meiotic division AND for sister chromatids to separate in the second meiotic division.

True

Which of the following indicates Turner syndrome?

XO

Huntington's disease is an example of a genetic disorder caused by __________.

a late-acting lethal dominant allele

What is an allele?

an alternative version of a gene

The core theme of biology, which explains both the unity and diversity of life, is _____.

evolution

DdEe pea plants can produce _____ type(s) of gametes, but a ddee plant can produce _____ type(s) of gametes.

four ... one

John and Jane are planning a family, but each has a brother who has sickle-cell disease, so they are concerned that their children may develop sickle-cell disease. Neither John, Jane, nor their respective parents have the disease. They consult a genetic counselor who tells them that __________.

it's possible that none of their children will have the disease, but blood tests on them both will be needed to make sure

Flower color in snapdragons is an example of incomplete dominance. If a red-flowered plant is crossed with a white-flowered plant, the F1 generation has pink flowers. If a pink-flowered plant is crossed with another pink-flowered plant, the expected progeny plants will be __________.

25% red, 50% pink, and 25% white

A human somatic cell contains _____ chromosomes.

46

A woman who is colorblind mates with a man with normal vision. What is the expected proportion of phenotypes from this cross?

50% females with color vision : 50% colorblind males

Polyploidy is involved in which of the following examples?

A normal watermelon has 22 chromosomes but seedless watermelons have 33 chromosomes.

In some cats, black coat color (B) is dominant over brown (b) and a striped fur pattern (S) is dominant over a marbled fur pattern(s). You rescued a black striped cat from an animal shelter but could not determine its exact genotype. To do so, you mated the cat with a brown marbled cat (apparently disregarding shelter policies to have animals spayed or neutered). The mating produced 3 brown marbled, 2 brown striped, 2 black marbled, and 3 black striped. Immediately, you concluded the genotype of your rescued cat was _____.

BbSs

Which of the following are NOT permitted at any time in POB lab classrooms?

Cell phones, gum, drinks, food, sandals, shorts

Indicate which of the following statements about lab safety are true. Select all that apply.

Close-toed shoes are required for all lab meetings. There is an eyewash station in your lab. Long hair must be restrained while in lab.

Complete the following paragraph to describe how independent assortment contributes to genetic variation.

During independent assortment, homologous chromosomes separate. This separation is random ; it is due to their alignment down the metaphase plate. The maternal or paternal homologue may be oriented toward either pole. This randomized separation aids in genetic variation for offspring. This variation helps in the long-term survival of the species.

Students may place toothpicks in their mouth as desired.

False

You may ingest the study organism during lab.

False

You will be able to view all the phases of spermatogenesis in the rat testes slide.

False

Why are lethal dominant alleles so much more rare than lethal recessive alleles?

Lethal dominant alleles are harmful whether they are carried in homozygous or heterozygous form, so there is always strong selection against these alleles.

Indicate which of the following should be done to properly clean and store the microscope. Select all that apply.

Light dimmer on lowest setting. Stage lowered. Lowest power objective in place. Lenses cleaned with lens paper.

Complete the following paragraph to describe the process of gamete production in females.

Meiosis in human females initiates during the development of the fetus. In the fetal ovaries, all of the diploid primary oocytes begin meiosis but cease development in prophase I. With puberty and the initiation of the menstrual cycle, a primary oocyte completes meiosis. It finishes the first meiotic division as two cells, each of which is haploid, although the chromosomes are still duplicated. One of these cells, termed the secondary oocyte, receives almost all of the cytoplasm. The other is the first polar body, a non-functioning cell. The polar body contains duplicated chromosomes but very little cytoplasm and may or may not divide again and eventually it disintegrates. If the secondary oocyte is fertilized by a sperm, it completes the second meiotic division, in which it again divides unequally, forming an egg and a second polar body. The chromosomes of the egg and sperm nuclei then join to form the 2n zygote. If the secondary oocyte is not fertilized by a sperm, it disintegrates and passes out of the body with the menstrual flow.

During _____ chromosomes align single file along the equator of a haploid cell.

Metaphase II

In giraffes, long necks (N), long legs (L), dark spots (D), and the ability to digest meat (M) are all dominant traits. What possible genotype could a long-necked, short-legged, light-spotted, meat-digesting giraffe have?

NnllddMM

Trisomy for most autosomes is fatal, yet trisomy or even tetrasomy (four copies) of the X chromosome is not. What is the explanation for this difference?

Only one copy of the X chromosome is functional, regardless of the total number of X chromosomes.

Drag the following statements to fit in their appropriate box on the figure in order to test your understanding of the mechanisms of evolution proposed by Darwin.

Originally, giraffe neck length varied Struggle to exist causes long-necked giraffes to have the most offspring Due to natural selection, most giraffes now have long necks

Drag the following statements to fit in their appropriate box on the figure in order to test your understanding of the mechanisms of evolution proposed by Lamarck

Originally, giraffes had short necks Giraffes stretched their necks in order to reach food With continual stretching most giraffes now have long necks

Synapsis occurs during _____.

Prophase 1

What should be used to clean the optical surfaces (lenses) of a microscope?

lens paper

Which of the following items are appropriate clothing to wear for a lab that will occur partially in the lab and partially outdoors?

long pants long pants a rain jacket if it looks rainy closed toe shoes

In humans and plants, fertilization occurs when the products of the process of _____ join together to form a new organism with genetic information from both parents

meiosis

Genetic variation in a population of animals or plants depends mainly on which of the following?

sexual recombination

In case of a broken slide, you should _____.

stop moving the microscope and notify your instructor immediately