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Science · Drill 62

Science practice 62

10 questions ~9 min recommended
⏱ 00:00
Score
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Gene1

P

Alleles

P. p

Genotypes

PP, Pp. pp

LL. LI, HI

ready children2

Table 1

Physical weathering

Mechanism

Animals and plants

Results

Animals burrow into the earth, moving rock fragments and sediment. Plant roots have the same effect.

Crystallization

Water evaporates from rock, which leads to the development of salt crystals. The crystals grow, eventually breaking apart the rock.

Temperature variation

Minerals in rocks expand and contract with temperature changes. Repeated expansion and contraction cracks and splits the rocks.

Exfoliation

Exfoliation occurs as slabs of cracked rock slip off other rock, which leads to further crosion3.

UVR (kJ m -3)

100

Average UVR Exposure

15

February

20

Amount of Chlorophyll per Experiment

1-UVR

1-PAR

2-UVR

2-PAR

3-UVR

3-PAR

0.8

0.8

0.7

0.7

0.2

0.2

2

1.2

0.9

1

1

Time (d)

4

1.3

1.5

4

1.3

6

1.4

17

1.2

15

2

10

8

24

80-

60-

40-

20-

Dead Cells Measured in Experiment 2

DUVR

•PAR

0+

Diatoms

Flagellates

shared4

48

Table 1 lists two genes found in Sesamum indicum (sesame), the possible alleles of each gene, and the possible genotypes for each gene.

Table 1

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Table 2 lists various sesame genotypes and the phenotype associated with each genotype. Each gene affects only one of the phenotype traits listed.

Table 2

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Table 3 lists four sesame plant crosses, the genotypes of the parents, and the percent of offspring that had each phenotype for the traits listed in Table 2. In each cross, each parent donated one allele to each offspring at each gene.

Table 3

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1. Based on Table 2, which of the 2 genes affects leaf texture?

2. Based on Table 2, a sesame plant with 2 recessive alleles for each of the 2 genes will have which of the following phenotypes?

3. Based on the information provided, all of the offspring of Cross 3 had 3 pods because each received:

4. In Cross 3, what percent of the offspring had genotype pp?

5. Based on the information provided, a sesame plant with 3 pods and normal leaves could have which of the following genotypes?

To determine the effect of ambient ultraviolet radiation (UVR) on the chlorophyll production, growth rate, and cell death of Antarctic phytoplankton, scientists conducted experiments on phytoplankton communities exposed to natural levels of solar radiation.

Experiments were conducted during three different periods of time. Experiment 1 took place February 1–6, Experiment 2 February 7–12, and Experiment 3 February 13–20. A meteorological station automatically recorded solar radiation for the duration of the study (see Figure 1).

The experiments involved sampling surface seawater, placing them in bottles submersed in incubators, and exposing them to either natural solar radiation (UVR) or radiation filtered to exclude ultraviolet radiation (PAR).

image

Figure 1

Every two days, duplicate samples were taken from each location to determine chlorophyll amounts and phytoplankton cell death (see Table 1 and Figure 2). Net population growth rates were calculated for diatoms and flagellates from the cell abundances obtained at the beginning and end of the experiments (see Figure 3).

Table 1

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image

Figure 2

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Figure 3

6. Based on the data in Table 1, how much chlorophyll was measured in Experiment 3 for the sample exposed to UVR after 4 days?

7. Based on the information presented in Table 1, UVR seems to have what effect on the amount of chlorophyll measured?

8. According to the data shown in Figure 3, which cells showed the least growth in Experiment 3?

9. Based on the information presented in Table 1, if Experiment 1 had been continued for another 2 days, the amount of chlorophyll measured in the samples that were not exposed to UVR would most likely be closest to what amount?

10. Based on the results displayed in Figure 2, it can be assumed that ultraviolet radiation (UVR) has what effect on the life of the diatoms and flagellates found in phytoplankton?

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