What would happen to a virus if it couldn't find a host cell to invade?

It wouldn't be able to multiply

It's genetic information would wither away

It wouldn't be able to travel through the air

What do viruses have in common with your body's cells?

Their genetic material is surrounded by a nucleus

They contain many complex organelles

What is the difference between DNA and RNA

DNA is a more complex molecule than RNA

RNA contains genetic information; DNA does no

DNA contains genetic information, RNA does no

RNA is a more complex molecule than DNA

What's the difference between a pathogenic virus and a harmless one?

Pathogenic viruses end up killing cells; harmless ones don't

Pathogenic viruses make copies of themselves; harmless ones don't

Pathogenic viruses get inside cells; harmless ones don't

Pathogenic viruses are surrounded by capsids; harmless ones aren't

What do the viruses that cause HIV, hepatitis, and ebola have in common?

They cannot replicate inside human cells

They are spread through contaminated water

Which of the following is a true statement about viruses?

They can be spread in a number of different way

They can only be spread through exposure to animal waste

They are only spread through person-to-person contact

All of them are harmful to human

What does a virus do once it's inside one of your cells?

It uses the cell's machinery to make copies of itself

It stays inside the cell for a while, and then leaves

It prevents the mitochondria from converting glucose to ATP

It eats up all of the machinery in the cell

What can you infer about the virus that causes the common cold?

It is pathogenic, but not usually deadly

It cannot be spread by person-to-person contac

It is usually deadly, but not pathogenic

If you have a cold, why should you cover your mouth when you sneeze?

To prevent other people from breathing in the viruses you expel

To get all of the cold viruses out of your body and onto your skin

To keep as many viruses as possible inside your body

To prevent viruses from infecting the cells in your nose and mouth

What does Tim mean when he says bacteria are the most abundant form of life on earth?

They're the most commonplace form of life on earth

They're the smallest form of life on earth

They're the most specialized form of life on earth

They're the most diverse form of life on earth

What do all bacteria have in common?

They're all single-celled organisms

They can all be found inside the human body

They're all multi-cellular organisms

How did bacteria make complex life on Earth possible?

By releasing oxygen into the atmosphere

By destroying life-inhibiting volcanoes

By evolving rapidly into multi-celled organisms

What might happen if you didn't have bacteria in your digestive tract?

Your body couldn't break down certain types of food

You wouldn't be able to eat vegetables

Your intestines would shut down

Nitrogen-fixing bacteria help plants thrive. What do nitrogen-fixing bacteria do

Convert nitrogen in the soil into a form that plants can absorb

Transform nitrogen into carbon dioxide

Absorb harmful nitrogen from the bodies of plants

Absorb nitrogen in the soil before it harms plants

Which of the following is a true statement about bacteria?

Bacteria can be both harmful and helpful to humans

Bacteria can grow to extremely large sizes

Most bacteria are harmful to humans

Bacteria exist in only a few environments on earth

What effect do antibiotics have on bacteria?

They prevent bacteria from digesting food

They help bacteria grow in size

How are bacterial cells different from plant and animal cells?

Bacterial cells contain almost no cell organelles

Bacterial cells have well-defined nuclei

Bacterial cells contain many more cell organelles

Bacterial cells have more complex cell organelles

Bacteria and Viruses Quiz

Differences Between Viruses and Bacteria - Starter Quiz

Bacteria and Viruses

Bacteria and Viruses Exit Ticket

Infection control and bacteria and viruses

Understanding the differences between bacteria and viruses is important because they affect our health differently. In this study guide, we'll explore the key distinctions between these two microorganisms. Section 1: Bacteria What are Bacteria? Bacteria are tiny, single-celled living organisms. They are found everywhere, including in soil, water, and inside our bodies. Shape and Structure: Bacteria have different shapes like rods, spheres, and spirals. They have a cell wall that surrounds their cell membrane. Reproduction: Bacteria reproduce by dividing in half, a process called binary fission. This allows them to multiply quickly. Living or Nonliving: Bacteria are considered living because they can grow, reproduce, and respond to their environment. Section 2: Viruses What are Viruses? Viruses are smaller than bacteria and are not considered living organisms. They are made up of genetic material (either DNA or RNA) surrounded by a protein coat. Shape and Structure: Viruses come in various shapes but are much simpler than bacteria. They lack the cell structures found in bacteria. Reproduction: Viruses cannot reproduce on their own. They need a host cell (like a human cell) to replicate and make more viruses. Living or Nonliving: Viruses are considered nonliving because they cannot perform life processes without a host cell. Section 3: Differences Now, let's compare bacteria and viruses: Size: Bacteria are larger than viruses. Living or Nonliving: Bacteria are living organisms. Viruses are non-living entities. Reproduction: Bacteria reproduce on their own through binary fission. Viruses need a host cell to replicate. Structure: Bacteria have complex structures with cell walls. Viruses are simpler, consisting of genetic material and a protein coat. Treatment: Bacterial infections are treated with antibiotics. Viral infections are typically managed with antiviral medications (if available) or through the body's immune response. Section 4: Examples Examples of bacteria-related and virus-related illnesses: Bacterial Infections: Strep throat, Urinary tract infections (UTIs), Tuberculosis Viral Infections: Influenza (Flu), Common cold, HIV/AIDS Conclusion: Understanding the differences between bacteria and viruses can help us stay healthy and make informed decisions about treatment. Remember that while bacteria can be both helpful and harmful, viruses rely on our cells to replicate and cause infections.

Differences between bacteria and viruses

Bio II Test - Bacteria and Viruses

Some substances, such as macromolecules and nutrients, are too large to pass through the cell membrane by the transport processes you have studied so far. Cells employ two other transport mecha- nisms—endocytosis and exocytosis—to move such substances into or out of cells. Endocytosis and exocytosis are also used to transport large quantities of small molecules into or out of cells at a single time. Both endocytosis and exocytosis require cells to expend energy. Therefore, they are types of active transport. Endocytosis Endocytosis (EN-doh-sie-TOH-sis) is the process by which cells ingest external fluid, macromolecules, and large particles, including other cells. As you can see in Figure 5-7, these external materials are enclosed by a portion of the cell’s membrane, which folds into itself and forms a pouch. The pouch then pinches off from the cell membrane and becomes a membrane-bound organelle called a vesicle. Some of the vesicles fuse with lysosomes, and their con- tents are digested by lysosomal enzymes. Other vesicles that form during endocytosis fuse with other membrane-bound organelles. Two main types of endocytosis are based on the kind of material that is taken into the cell: pinocytosis (PIEN-oh-sie-TOH-sis) involves the transport of solutes or fluids, and phagocytosis (FAG-oh-sie-TOH-sis) is the movement of large particles or whole cells. Many unicellular organisms feed by phagocytosis. In addition, certain cells in animals use phagocytosis to ingest bacteria and viruses that invade the body. These cells, known as phagocytes, allow lysosomes to fuse with the vesicles that contain the ingested bacteria and viruses. Lysosomal enzymes then destroy the bacteria and viruses before they can harm the animal. CYTOSOL EXTERNAL ENVIRONMENT During endocytosis, the cell membrane folds around food or liquid and forms a small pouch. The pouch then pinches off from the cell membrane to become a vesicle. FIGURE 5-7 vesicle from the Latin vesicula, meaning “bladder” or “sac” Word Roots and Origins www.scilinks.org Topic: Endocytosis Keyword: HM60505 mb06se_homs02.qxd 5/18/07 11:03 AM Page 105 106 CHAPTER 5 1. Explain the difference between passive trans- port and active transport. 2. What functions do carrier proteins perform in active transport? 3. What provides the energy that drives the sodium-potassium pump? 4. Explain the difference between pinocytosis and phagocytosis. 5. Describe the steps involved in exocytosis. 6. How do endocytosis and exocytosis differ? How can that difference be seen? CRITICAL THINKING 7. Analyzing Information During intense exercise, potassium tends to accumulate in the fluid surrounding muscle cells. What membrane protein helps muscle cells counteract this tendency? Explain your answer. 8. Evaluating Differences How does the sodium- potassium pump differ from facilitated diffusion? 9. Relating Concepts The vesicles formed during pinocytosis are much smaller than those formed during phagocytosis. Explain. SECTION 2 REVIEW Vesicle Cell membrane EXTERNAL ENVIRONMENT CYTOSOL During exocytosis, a vesicle moves to the cell membrane, fuses with it, and then releases its contents to the outside of the cell. FIGURE 5-8 INSIDE OF CELL Vesicle OUTSIDE OF CELL Exocytosis Exocytosis (EK-soh-sie-TOH-sis) is the process by which a substance is released from the cell through a vesicle that transports the sub- stance to the cell surface and then fuses with the membrane to let the substance out of the cell. This process, illustrated in Figure 5-8, is basically the reverse of endocytosis. During exocytosis, vesi- cles release their contents into the cell’s external environment. Figure 5-8 also shows a photo of a vesicle during exocytosis. Cells may use exocytosis to release large molecules such as pro- teins, waste products, or toxins that would damage the cell if they were released within the cytosol. Recall that proteins are made on ribosomes and packaged into vesicles by the Golgi apparatus. The vesicles then move to the cell membrane and fuse with it, deliver- ing the proteins outside the cell. Cells in the nervous and endocrine systems also use exocytosis to release small molecules that control the activities of other cells.

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