STAAR Practice DOK 3

The cellular process known as the sodium-potassium pump was discovered in the 1950s by Jens Christian Skou, a Danish scientist. This process is a form of active transport that moves three sodium ions to the outside of a cell for every two potassium ions that it moves into the cell. Which of these best explains why energy is needed for active transport?

• Ions are negatively charged.

• Ions are attached to large proteins.

• Ions are trapped inside the plasma membrane.

• Ions are moved against the concentration gradient.

Tags

NGSS.MS-LS1-7

Limax maximus also known as the Great Slug is a species of slug in the family Limacidae. This species of slug can be found in lawns, gardens, and other moist areas. Limax maximus have omnivorous feeding habits. They are known to eat dead plants, fungi, other slugs, and also crops. In an effort to control the slug population in local farms, some Florida farmers use a sodium chloride solution to kill the slugs on contact. The skin of a slug is a semi-permeable membrane. How does the process of osmosis cause the body of the slug to dehydrate and eventually die?

• The cells of the slug will take up liquid from the surrounding environment once the sodium chloride comes in contact with the skin.

• The diffusion of water out of the cell will occur because there is a higher concentration of solute on the outside of the skin.

• Ions of sodium chloride are carried across the skin by proteins in the membrane that act like pumps.

• The diffusion of sodium chloride will move from an area of higher concentration to an area of lower concentration.

Tags

NGSS.MS-LS1-5

This diagram shows cellular activity across a cell membrane.

Which two processes does this diagram most directly model?

• Energy conversions and synthesis of new molecules

• Synthesis of new molecules and homeostasis

• Transport of molecules and energy conversions

• Homeostasis and transport of molecules

Severe acute respiratory syndrome (SARS) is an illness caused by a coronavirus. Symptoms including a high fever, headaches, and body aches typically occur two to seven days after infection by the virus. SARS is more serious in elderly patients. This information suggests that the reproductive cycle of the SARS virus is —

• lysogenic, because the virus is a coronavirus

• lytic, because the virus causes respiratory illness

• lysogenic, because the virus primarily affects older people

• lytic, because of the quick onset of symptoms after infection

Cold sores are caused by the herpes simplex virus type 1. A company that wants to develop antiviral drugs would ask a research immunologist to study —

• the mechanism used by the virus to infect cells

• how closely related the virus is to cold viruses

• the metabolism of the virus

• meiosis in the virus

The picture shows a 3-D model of a virus called a bacteriophage. Bacteriophages can infect bacteria such as E. coli.

In what way are the bacteriophage and E. coli alike?

• They contain antibodies.

• They reproduce by mitosis.

• They have identical genomes.

• They lack membrane-bound organelles.

A photograph of a virus is shown above.

The projections on the surface of this virus allow the virus to—

• move inside a host cell

• attach to a host cell

• control a host cell’s DNA

• signal other viruses to infect a host cell

The bacteria Bacillus thuringiensis produce protein crystals that are toxic to the digestive system of insects. How can these bacteria be used to control insects in crops?

• Apply the bacteria to growing plants.

• Expose the bacteria to low levels of light.

• Remove plants from areas containing the bacteria.

• Treat the bacteria with a solution of the protein crystals.

Tags

NGSS.MS-LS2-4

NGSS.MS-LS2-5

Lactose is a naturally occurring sugar found in milk. Some dairy products, such as yogurt, may contain live bacteria. These products are useful to people who lack the ability to digest lactose. What does this information demonstrate?

• Bacteria raise the acidity of processed foods.

• Some bacteria interfere with digestion.

• Bacteria can prevent insulin production.

• Some bacteria are beneficial to human health.

Surtsey is an island located south of Iceland. The island was formed by a volcanic eruption and first appeared in 1963. The table above contains descriptions of changes in the population and diversity of species on Surtsey.

Which of these lists the descriptions in the correct order of ecological succession on Surtsey?

• I, II, IV, III

• III, I, II, IV

• IV, III, I, II

• II, IV, I, III

Tags

NGSS.MS-LS2-1

NGSS.MS-LS2-3

NGSS.MS-LS2-4