7th gr Benchmark 2 practice

The diagram shows a single-celled organism moving on a surface. The dotted line in the diagram shows the previous form of the organism as it moves. Which characteristic of the cytoplasm is shown by the single-celled organism?

• The cytoplasm can remove wastes from the single-celled organism and is able to change the cell shape.

• The cytoplasm can store nutrients in the single-celled organism but needs other organelles to break down the nutrients.

• The cytoplasm can release energy in the single-celled organism and responds to changes in the environment.

• The cytoplasm can move within the single-celled organism but is contained by the cell membrane.

Answer explanation

The organism's movement indicates that the cytoplasm can flow within the cell, allowing shape changes while being contained by the cell membrane. This characteristic is essential for its mobility.

Tags

NGSS.MS-LS1-2

NGSS.MS-LS1-1

The opening and closing of the stoma play a significant role in maintaining homeostasis within plant leaves. When a stoma is open, excess water can leave the plant by evaporation. When the stoma is closed, the plant reduces water loss. Based on the diagram, a student claims that passive transport helps maintain homeostasis in plants. Is the claim made by the student correct, and why?

• Yes. Potassium ions and water molecules can flow in both directions.

• Yes. Water molecules move from areas of higher concentration to lower concentration.

• No. Potassium ions move from a lower concentration to a higher concentration.

• No. The flow of potassium ions and water molecules is based on outside temperature.

Answer explanation

Yes, the claim is correct. Water molecules move from areas of higher concentration to lower concentration, facilitating passive transport and helping maintain homeostasis by regulating water loss through the stoma.

Tags

NGSS.MS-LS2-3

Use the information to answer the question. Calcium carbonate (CaCO₃) is heated to form calcium oxide (CaO) and carbon dioxide (CO₂). What happens to calcium carbonate after it is heated?

• A new pure substance is formed that cannot be separated by physical means.

• Atoms in the original substance are changed into different atoms to form new substances.

• A new mixture is formed that cannot be separated by physical means.

• Atoms in the original substance are rearranged to form new substances.

Answer explanation

When calcium carbonate is heated, it undergoes a chemical reaction where its atoms are rearranged to form new substances, calcium oxide and carbon dioxide, rather than changing into different atoms.

Tags

NGSS.MS-PS1-2

NGSS.MS-PS1-5

Use the information to answer the question. Calcium carbonate (CaCO₃) is heated to form calcium oxide (CaO) and carbon dioxide (CO₂). Why is the mass of the products lower than the mass of the reactant?

• One of the products is a gas that escaped into the air and could not be measured easily.

• The reaction does not follow the Law of Conservation of Mass.

• The mass of solids does not contribute to the mass of the products in a chemical reaction.

• Matter is destroyed during the chemical reaction.

Answer explanation

The mass of the products is lower because carbon dioxide (CO₂), a gas, escapes into the air during the reaction and cannot be measured easily, leading to a loss in mass.

Tags

NGSS.MS-PS1-2

NGSS.MS-PS1-5

Which statement correctly explains the difference between elemental and compound molecules?

• Elemental molecules are always composed of two or more types of atoms, while compound molecules are always composed of a single type of atom.

• Elemental molecules are always composed of a single type of atom, while compound molecules are always composed of two or more types of atoms.

• Elemental molecules are always composed of three or more types of atoms, while compound molecules are always composed of a single type of atom.

• Elemental molecules are always composed of a single type of atom, while compound molecules are always composed of three or more types of atoms.

Answer explanation

The correct choice states that elemental molecules consist of a single type of atom, while compound molecules are made up of two or more different types of atoms. This accurately defines the distinction between the two types of molecules.

Tags

NGSS.MS-PS1-1

The leaves of the mimosa plant fold, and the branches droop when the plant is touched. The leaves and branches perform this action due to the passive transport of water from their cells.

• The cells swell as water moves out of them, making the branches droop.

• The cells swell as water moves into them, making the branches droop.

• The cells shrink as water moves out of them, making the branches droop.

• The cells shrink as water moves into them, making the branches droop.

Answer explanation

When the mimosa plant is touched, water moves out of the cells, causing them to shrink. This loss of turgor pressure leads to the drooping of branches and folding of leaves, making the correct choice: 'The cells shrink as water moves out of them.'

Tags

NGSS.MS-LS1-2

Which of the following substances can pass through the cell membrane during passive transport?

• Water

• Oxygen

• Carbon dioxide

• All of the above

Answer explanation

All of the substances listed—water, oxygen, and carbon dioxide—can pass through the cell membrane via passive transport, which does not require energy. Therefore, the correct answer is 'All of the above'.

What is the primary role of the cell membrane in both organisms?

• To produce nutrients

• To control the movement of substances in and out of the cell

• To generate energy

• To store genetic material

Answer explanation

The primary role of the cell membrane is to control the movement of substances in and out of the cell, maintaining homeostasis and allowing communication with the environment, which is essential for all organisms.

Tags

NGSS.MS-LS1-2

The cell wall is present in both Organism 1 and Organism 2.

• True

• False

Answer explanation

The statement is false because not all organisms have a cell wall. For example, animal cells lack a cell wall, while plant cells do have one. Therefore, it cannot be true that both Organism 1 and Organism 2 have a cell wall.

Tags

NGSS.MS-LS1-1

In Table 1, Organism 2 contains free-floating genetic material. Where does Organism 1 contain its genetic material?

• nucleus

• mitochondrion

• large chloroplast

• cytoplasm

Answer explanation

Organism 1 contains its genetic material in the nucleus, which is typical for eukaryotic cells. In contrast, Organism 2 has free-floating genetic material, indicating it may be prokaryotic.

Tags

NGSS.MS-LS1-2

NGSS.MS-LS1-1