Cells and Viruses Preassessment

What is the basic unit of life?

• Atom

• Molecule

• Cell

• Organ

Answer explanation

The cell is the basic unit of life, as it is the smallest structure capable of performing all life processes. Atoms and molecules are components of cells, while organs are made up of multiple cells.

Tags

NGSS.MS-LS1-1

NGSS.MS-LS1-2

What structure contains the genetic material in eukaryotic cells?

• Ribosome

• Mitochondria

• Nucleus

• Cell membrane

Answer explanation

The nucleus is the structure in eukaryotic cells that contains the genetic material, including DNA. Ribosomes are involved in protein synthesis, mitochondria generate energy, and the cell membrane protects the cell.

Tags

NGSS.HS-LS3-1

Which of these is found in plant cells but not in animal cells?

• Cell membrane

• Cytoplasm

• Cell wall

• Mitochondria

Answer explanation

The cell wall is a rigid structure found in plant cells that provides support and protection. In contrast, animal cells do not have a cell wall; they only have a flexible cell membrane. Thus, the correct answer is the cell wall.

Tags

NGSS.MS-LS1-1

NGSS.MS-LS1-2

What does the term "prokaryote" refer to?

• Cells with a nucleus

• Cells without a nucleus

• Viruses

• Multicellular organisms

Answer explanation

The term "prokaryote" refers to cells without a nucleus. Prokaryotic cells, such as bacteria, lack a membrane-bound nucleus, distinguishing them from eukaryotic cells, which do have a nucleus.

Which of the following is true about all cells?

• They have a cell wall

• They have a nucleus

• They contain DNA

• They have chloroplasts

Answer explanation

All cells contain DNA, which carries genetic information. Not all cells have a cell wall, nucleus, or chloroplasts, as these features are specific to certain types of cells, like plant cells.

What is the main difference between prokaryotic and eukaryotic cells?

• The presence or absence of a cell membrane

• The presence or absence of DNA

• The presence or absence of a nucleus

• The presence or absence of cytoplasm

Answer explanation

The main difference between prokaryotic and eukaryotic cells is the presence of a nucleus. Eukaryotic cells have a defined nucleus that houses DNA, while prokaryotic cells do not have a nucleus.

Which of these is NOT considered a living organism?

• Bacteria

• Plant

• Animal

• Virus

Answer explanation

A virus is not considered a living organism because it cannot reproduce or carry out metabolic processes on its own. Unlike bacteria, plants, and animals, viruses require a host cell to replicate.

What do viruses need to reproduce?

• Sunlight

• Water

• A host cell

• Oxygen

Answer explanation

Viruses cannot reproduce on their own; they require a host cell to replicate. The host cell provides the necessary machinery and environment for the virus to multiply, making 'a host cell' the correct answer.

Which of the following structures is responsible for energy (ATP) production in cells?

• Nucleus

• Ribosome

• Mitochondria

• Golgi apparatus

Answer explanation

The mitochondria are known as the powerhouse of the cell, as they are responsible for producing ATP, the energy currency of the cell, through cellular respiration. The other structures listed do not perform this function.

Tags

NGSS.HS-LS1-7

What is the function of ribosomes in a cell?

• DNA replication

• Protein synthesis

• Lipid production

• Energy storage

Answer explanation

Ribosomes are essential for protein synthesis in a cell, as they translate messenger RNA (mRNA) into amino acid sequences, forming proteins. This process is crucial for cell function and growth.