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Science · Drill 6

Science practice 6

14 questions ~9 min recommended
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Organism

Adder's-tongue fern

Coyote

Dog

Horse

Donkey

Bengal fox

Silkworm

Pineapple

Zebra fish

Potato

Human

Oats

Mouse

Earthworm

Red fox

Alfalfa

European honeybee

Yeast

Slime mold

Swamp wallaby

Fruit fly

Jack jumper ant

Scientific Name

Ophioglossum reticulatum

Canis latrans

Canis lupus familiaris

Equus ferus caballus

Equus africanus asinus

Vulpes bengalensis

Bombyx mori

Ananas comosus

Danio rerio

Solanum tuberosum

Homo sapiens

Avena sativa

Mus musculus

Lumbricus terrestris

Vulpes vulpes

Medicago sativa

Apis mellifera

Saccharomyces cerivisiae

Dictyostelium discoideum

Wallabia bicolor

Drosophila melanogaster

Myrmecia pilosula

Diploid Number of Chromosomes

1,260

78

78

64

62

60

54

50

50

481

46

422

40

36

34

321

323

32

12

10/114

8

1Organism is a tetraploid.

2Organism is a hexaploid.

3Males are haploid.

Males have one less chromosome than females.567891011121314

An organism's genetic information is stored within the nuclei of its cells as a set of chromosomes. The number of chromosomes in a cell varies from species to species. In some species, the number of chromosomes can vary between individuals. Table 2.1 lists the chromosome count for a variety of species.

TABLE 2.1 Species Chromosome Count

Source: http://en.wikipedia.org/wiki/List_of_organisms_by_chromosome_count.

Ploidy is the number of sets of chromosomes present in the cell of an organism. The monoploid number (x) is the number of chromosomes an organism has in one set.

In most species, a gamete (sex cell) contains one complete set of an organism's chromosomes. The number of chromosomes in a gamete is referred to as the haploid number (n). The fusing of two gametes into a zygote during sexual reproduction produces somatic cells (body cells) containing two complete sets of chromosomes. The total number of chromosomes in a somatic cell is referred to as the diploid number (2n). In most species, the monoploid number (x) and the haploid number (n) are the same.

Some species have more than two sets of chromosomes present in their cells, a condition referred to as polyploidy. The somatic cells of triploid organisms have three sets of chromosomes, for example, and tetraploids have four. In polyploidy organisms, the term haploid is still used to describe the number of chromosomes in a gamete, and diploid is used to describe the number of chromosomes in a somatic cell. However, the monoploid number and the haploid number are not the same in a polyploidy organism.

1. Based on the information in Table 2.1, which species does not exhibit variation in chromosome numbers between individuals?

2. The first part of an organism's scientific name identifies the genus to which it belongs. Which statement about the members of a genus is best supported by the information in Table 2.1?

3. Based on the information in Table 2.1, the relationship between diploid chromosome count and organism complexity can best be described as exhibiting:

4. To which kingdom does the organism exhibiting the greatest diploid number of chromosomes in Table 2.1 belong?

5. Which species has more chromosomes than a human but fewer chromosomes than a dog?

6. Cells from which pair of organisms have the same number of chromosomes in their nuclei?

7. A team of scientists have discovered three previously unknown insect species in the Amazon rain forest. Which statement about the genetic information of these species is best supported by the data in Table 2.1?

8. Based on the information in the passage, which species produces gametes that each contain 32 chromosomes?

9. According to the information in Table 2.1, how many more total chromosomes does a female European honeybee have than a male?

10. Based on the information in the passage, the total number of chromosomes in a somatic cell is represented by which of the following terms?

11. Which statement about polyploidy is supported by the information in the passage?

12. Which of the following organisms has four complete sets of chromosomes in its somatic cells?

13. Table 2.1 identifies the oat species Avena sativa as a hexaploid, containing six sets of chromosomes. The numerical representation 2n = 6x = 42 describes the total number of chromosomes in a somatic cell of this hexaploid species. How many chromosomes does Avena sativa have in one set?

14. Which of the following correctly identifies the relationship between the diploid number (2n), haploid number (n), and monoploid number (x) of Solanum tuberosum?

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