Chapter 20-21 Review

While exploring a forest, you notice an organism growing on decaying wood. This organism plays a crucial role in breaking down organic matter. What type of organism is it?

• A. A parasite that feeds on the host

• B. A producer that makes its own food

• C. A decomposer that recycles nutrients

• D. A predator that hunts other organisms

A researcher is examining two microscopic particles under a powerful microscope. One consists only of genetic material surrounded by a protein coat, while the other has a cell wall and ribosomes. What can be inferred?

• The first is a bacterium, and the second is a virus

• The first is a virus, and the second is a bacterium

• Both are bacteria

• Both are viruses

A newly discovered virus has tail-like structures that attach to a host cell before releasing its genetic material. What is the primary purpose of these structures?

• To produce energy for the virus

• To store viral DNA for future use

• To help the virus reproduce on its own

• To bind to and inject genetic material into a host cell

Some viruses remain inactive inside host cells for long periods before suddenly becoming active and multiplying. What type of cycle is this?

• A. Lytic cycle

• B. Lysogenic cycle

• C. Binary fission

• D. Budding

A type of algae lives inside a coral, providing it with food through photosynthesis, while the coral provides protection. This is an example of what kind of relationship?

• A. One organism benefits, and the other is harmed

• B. Both organisms benefit from the relationship

• C. One organism benefits, and the other is unaffected

• D. One organism hunts the other for food

What ability do organisms such as plants and algae share that supports ecosystems?

• They consume other organisms for food

• They decompose dead organic material

• They create energy from sunlight and release oxygen

• They compete for carbon monoxide in the environment.

What is a distinguishing feature of bacteria when compared to eukaryotic cells?

• Bacteria have a nucleus

• Bacteria have membrane-bound organelles

• Bacteria lack a nucleus

• Bacteria are typically multicellular.

Scientists frequently use bacterial DNA in research because: A. Bacteria have more complex DNA than other organisms B. Bacteria have multiple types of DNA molecules C. Bacterial DNA is simple and easy to manipulate D. Bacterial DNA is stored inside a protective nucleus.

• A. Bacteria have more complex DNA than other organisms

• B. Bacteria have multiple types of DNA molecules

• C. Bacterial DNA is simple and easy to manipulate

• D. Bacterial DNA is stored inside a protective nucleus.

How does a retrovirus differ from most other viruses?

• It contains DNA instead of RNA

• It contains RNA and converts it into DNA inside the host

• It lacks genetic material entirely

• It is unable to replicate inside a host.

Fill in the blank: Antibiotics are effective against bacterial infections but not against viruses because ____.

• A. viruses have a different structure

• B. viruses are not living organisms

• C. viruses do not have a cell wall

• D. viruses replicate inside host cells.