TNReady Review #1: LS1.1, LS1.2, LS1.3

Viruses are simple particles that contain either DNA or RNA protected by a protein coat. Which statement best suggests why viruses must have host cells to replicate their genetic materials and build new particles?

• They lack the ability to enter host cells.

• They lack enzymes necessary to carry out metabolic reactions.

• They lack the Golgi complexes necessary to carry out metabolic reactions.

• They lack nucleic acids necessary to pass on traits.

Answer explanation

Viruses cannot replicate independently because they lack the enzymes necessary to carry out metabolic reactions. They rely on host cells to provide the machinery needed for replication and assembly of new viral particles.

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TN.BIO1.LS1.1.

The table shows the characteristics of two microscopic organisms.

Based on the table, how are the organisms classified?

• Both organisms are classified as viruses.

• Both organisms are classified as bacteria.

• Organism P is a bacterium, and Organism Q is a virus.

• Organism P is a virus, and Organism Q is a bacterium.

Answer explanation

Organism P is classified as a bacterium due to its cellular structure, while Organism Q is identified as a virus because it lacks cellular components and requires a host to replicate. Thus, the correct classification is that Organism P is a bacterium, and Organism Q is a virus.

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TN.BIO1.LS1.1.

Which statement best explains why viruses are considered to be nonliving?

• They are only able to be viewed with a microscope.

• They are unable to reproduce independently.

• They lack genetic material.

• They have different types of proteins.

Answer explanation

Viruses are considered nonliving because they cannot reproduce independently; they require a host cell to replicate. This inability to self-replicate is a key characteristic that distinguishes them from living organisms.

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TN.BIO1.LS1.1.

Scientists claim that viruses are not living. Which evidence supports the classification of viruses as nonliving?

• Viruses are unable to change or evolve over time.

• Viruses must use their host’s cellular machinery in order to reproduce.

• Viruses cause many different types of diseases.

• Viruses lack genetic material that can be passed to future generations.

Answer explanation

Viruses lack the ability to reproduce independently, which is a key characteristic of living organisms. This inability to reproduce without a host supports their classification as nonliving.

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TN.BIO1.LS1.1.

Which characteristic do viruses share with living things?

• They both contain organelles such as ribosomes.

• They both are surrounded by a protein coat.

• They both contain genetic material.

• They both are surrounded by a cell membrane.

Answer explanation

Viruses and living organisms both contain genetic material, which is essential for replication and functioning. Viruses do not have a cell membrane or organelles, and living cells do not have a protein coat.

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TN.BIO1.LS1.1.

A student claims that a leaf from an oak tree is living, and a plastic leaf is nonliving. Which statement provides evidence to support the claim?

• The plastic leaf can reproduce.

• The plastic leaf can grow and develop.

• The plastic leaf lacks a cellular structure.

• The plastic leaf lacks the ability to move.

Answer explanation

The statement "The plastic leaf lacks a cellular structure" supports the claim because living organisms, like the oak leaf, are made of cells, while nonliving things, like the plastic leaf, do not have this characteristic.

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TN.BIO1.LS1.1.

A scientist conducts an experiment on a virus and a species of bacteria. The virus and the bacteria are put in the same Petri dish for 24 hours and provided a food source. The scientist notices that the number of bacteria increases significantly, whereas the virus makes no change.

Which conclusion does the experiment best support?

• Viruses are incapable of making sugar.

• Viruses are incapable of self-replication.

• Viruses require multiple days to complete the cell cycle.

• Viruses require proteins to replicate at fast rates.

Answer explanation

The experiment shows that the virus did not replicate while the bacteria increased in number. This supports the conclusion that viruses are incapable of self-replication, as they rely on host cells to reproduce.

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TN.BIO1.LS1.1.

Use the diagram of a plant cell to answer the question.

For the process of photosynthesis, the arrow labeled A would most likely be pointing to what organelle?

• Cell Wall

• Chloroplast

• Mitochondria

• Nucleus

Answer explanation

The chloroplast is the organelle responsible for photosynthesis, where plants convert sunlight into energy. Therefore, the arrow labeled A is most likely pointing to the chloroplast.

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TN.BIO1.LS1.2.

Which cell organelle is correctly aligned with its function?

• chloroplast - controls cell function

• cytoplasm - digests old cell parts

• mitochondrion - stores wastes

• ribosome - produces proteins

Answer explanation

The ribosome is correctly aligned with its function as it is responsible for producing proteins, which are essential for various cellular processes. The other options incorrectly match organelles with their functions.

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TN.BIO1.LS1.2.

What cell structures are responsible for providing the energy needed for cell activities?

• mitochondria

• nuclei

• ribosomes

• vacuoles

Answer explanation

Mitochondria are known as the powerhouse of the cell, as they generate ATP, the energy currency required for various cellular activities. Other structures like nuclei, ribosomes, and vacuoles do not primarily provide energy.

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TN.BIO1.LS1.2.