Science Lab: Unleashed! 1.4, 1.5, 1.6

An adult human body contains trillions of cells. Body cells go through the stages of the cell cycle. A diagram of the cell cycle is shown.

Describe two events that occur during the interphase stage of the cell cycle.

An adult human body contains trillions of cells. Body cells go through the stages of the cell cycle. A diagram of the cell cycle is shown.

Part B

Mitosis and cytokinesis are important stages of the cell cycle.

Explain why mitosis must occur before cytokinesis.

Tags

NGSS.HS-LS1-4

An adult human body contains trillions of cells. Body cells go through the stages of the cell cycle. A diagram of the cell cycle is shown.

• 
  Part C

Describe one way a person’s body would be affected if cells stopped going through mitosis and cytokinesis.

Tags

NGSS.HS-LS1-4

In a sample of double-stranded DNA, 20% of the nitrogenous bases are adenine (A). What percentage of the nitrogenous bases in the sample are cytosine (C)?

• 10%

• 30%

• 60%

• 80%

In North America, the populations of six species of bats have decreased by up to 99% since 2006. These decreases in population sizes are largely due to white-nose syndrome (WNS). WNS is caused by a fungus that infects the skin on bats’ wings, ears, and noses. The infected skin, which often appears white, loses more water than healthy, normal skin.

One species of bat affected by WNS is the little brown bat. This bat has a very small mass (about 14 g) and hunts for flying insects at night. Females typically give birth to one offspring per year.

In preparation for winter, little brown bats eat more insects to build up fat reserves in their bodies. In winter, they hibernate, which decreases body temperature, breathing rate, and metabolic rate. The bats do not eat while they are hibernating.

Little brown bats typically wake up only for brief periods of time during hibernation. When a bat does wake up, its body temperature increases as it flies around.

WNS affects the number of times that a bat wakes up during hibernation. Healthy bats wake up once every 20 days, and about 80% survive hibernation. Bats infected with WNS wake up once every 9 days, and only about 4% survive hibernation.

The graph shows the amount of fat lost during hibernation in healthy bats and in WNS‑infected bats in North America.

WNS causes damage to tissue on the wings, ears, and noses of bats. Which of the following processes most directly helps repair this damaged tissue?

• active transport

• lipid storage

• meiosis

• mitosis

Tags

NGSS.MS-LS1-5

NGSS.MS-LS2-4

A student is studying how flowering plants and insects affect oxygen (O₂) and carbon dioxide (CO₂) concentrations in the air.

Part A

Identify the cellular process performed only by the flowering plants that affects the concentrations of O₂ and CO₂ in the air.

Tags

NGSS.HS-LS1-5

NGSS.HS-LS2-5

A student is studying how flowering plants and insects affect oxygen (O₂) and carbon dioxide (CO₂) concentrations in the air.

Part B

Identify the cellular process performed by both the flowering plants and the insects that affects the concentrations of O₂ and CO₂ in the air.

Tags

NGSS.HS-LS1-5

NGSS.HS-LS1-7

NGSS.HS-LS2-5

Part C

A student is studying how flowering plants and insects affect oxygen (O₂) and carbon dioxide (CO₂) concentrations in the air.

During an experiment, the student measured the initial concentrations of O₂ and CO₂ in three flasks, added organisms to some of the flasks, sealed the flasks, and placed them under a light. After 12 hours, the student measured the concentrations of O₂ and CO₂ in the flasks. The results for each flask are shown in the table.

During the experiment, the student had forgotten to identify the contents of each flask. Each of the three flasks contained one of the following: two plants and one insect; one insect; or no organisms.

Two plants, One Insect: Row ___

One Insect: Row ___

No Organisms: Row ___

Tags

NGSS.HS-LS1-5

NGSS.HS-LS2-3

NGSS.HS-LS2-5

Corn is one of the most important crops grown in the United States. Corn, which is mostly starch, is used as a food source for humans and other animals.

Humans first developed corn as a food crop over 8000 years ago. These early farmers produced corn by selectively breeding a wild grass called teosinte. The kernels of teosinte have a hard coating that makes them difficult for humans to eat. A key step in developing corn as a food crop was selecting individual plants that produced kernels without this coating so that they could more easily be used as a food source.

Corn and teosinte share the scientific name Zea mays. A single gene with two alleles codes for kernel coating (H) or no kernel coating (h) in Zea mays. To determine the inheritance pattern of this gene, scientists crossed teosinte that is true-breeding (homozygous) for kernel coating and domestic corn that is true-breeding for no kernel coating to produce offspring with partially formed kernel coatings.

Corn plants produce their own food through a chemical process. Fill in the blanks in the equation to show the chemical reaction corn plants use to make food.

6 ___ + 6 ___ -> ___ + 6 ___

Each chemical symbol may be used once or not at all.

CO2 C3H803 C6H12O6 H2CO3 H20 O2

Tags

NGSS.HS-LS1-5

NGSS.HS-LS2-5

Corn is one of the most important crops grown in the United States. Corn, which is mostly starch, is used as a food source for humans and other animals.

Humans first developed corn as a food crop over 8000 years ago. These early farmers produced corn by selectively breeding a wild grass called teosinte. The kernels of teosinte have a hard coating that makes them difficult for humans to eat. A key step in developing corn as a food crop was selecting individual plants that produced kernels without this coating so that they could more easily be used as a food source.

Corn and teosinte share the scientific name Zea mays. A single gene with two alleles codes for kernel coating (H) or no kernel coating (h) in Zea mays. To determine the inheritance pattern of this gene, scientists crossed teosinte that is true-breeding (homozygous) for kernel coating and domestic corn that is true-breeding for no kernel coating to produce offspring with partially formed kernel coatings.

Corn plants produce their own food through a chemical process called _______________.

Tags

NGSS.HS-LS1-5

NGSS.HS-LS2-5