Microorganisms and Body Defenses
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Questions and Answers

What is the size limit for organisms that are considered microbes?

Less than 1mm

How many species of bacteria are estimated to reside in the human mouth?

700

All bacteria are harmful to humans.

False

What is the role of bacteria in the soil?

<p>Breakdown of dead materials</p> Signup and view all the answers

Bacteria can contribute to plant growth by introducing nitrogen into the soil.

<p>True</p> Signup and view all the answers

Where are protists typically found?

<p>Freshwater</p> Signup and view all the answers

What causes people to get sick?

<p>Pathogens</p> Signup and view all the answers

Which of the following is NOT a way diseases can be transmitted?

<p>Airborne particles</p> Signup and view all the answers

What is the first line of defense against pathogens?

<p>The skin</p> Signup and view all the answers

What substance helps prevent pathogens from growing on skin?

<p>Sweat and oil</p> Signup and view all the answers

What lines the nose and prevents pathogens from entering the body?

<p>Mucus</p> Signup and view all the answers

Tears and eyelashes protect the eyes from pathogens.

<p>True</p> Signup and view all the answers

What prevents things from entering the ears?

<p>Ear wax</p> Signup and view all the answers

What is the term for increased blood flow in the area of an infection?

<p>Inflammation</p> Signup and view all the answers

Fever can potentially kill viruses.

<p>True</p> Signup and view all the answers

What type of cell swallows invading organisms?

<p>White blood cells</p> Signup and view all the answers

Which of the following is NOT a characteristic of life?

<p>Maintain a constant internal temperature</p> Signup and view all the answers

Scientists used to believe that life could arise spontaneously from nonliving matter.

<p>True</p> Signup and view all the answers

What is the cell theory?

<p>It is the foundation for understanding living organisms</p> Signup and view all the answers

Early microscopes were powerful enough to see the internal structures of cells.

<p>False</p> Signup and view all the answers

What type of microscope is required to see viruses?

<p>Electron microscope</p> Signup and view all the answers

What is the basic structure of a virus?

<p>A piece of DNA or RNA surrounded by a protective protein coat</p> Signup and view all the answers

How do viruses reproduce?

<p>By injecting their DNA or RNA into a host cell</p> Signup and view all the answers

Unicellular organisms consist of multiple cells.

<p>False</p> Signup and view all the answers

What does multicellular mean?

<p>More than one cell</p> Signup and view all the answers

What are the two main types of cells?

<p>Prokaryotic and eukaryotic</p> Signup and view all the answers

A bacterium is an example of a eukaryotic cell.

<p>False</p> Signup and view all the answers

Prokaryotic cells are enclosed within a nucleus.

<p>False</p> Signup and view all the answers

Prokaryotic cells are not surrounded by a membrane.

<p>False</p> Signup and view all the answers

Prokaryotic cells are smaller and less complex compared to eukaryotic cells.

<p>True</p> Signup and view all the answers

Provide an example of a eukaryotic cell.

<p>A liver cell of an animal</p> Signup and view all the answers

The genetic material of a eukaryotic cell is enclosed within a nucleus.

<p>True</p> Signup and view all the answers

Eukaryotic cells are surrounded by a membrane.

<p>True</p> Signup and view all the answers

How much larger are eukaryotic cells compared to prokaryotic cells?

<p>10 times larger</p> Signup and view all the answers

Both prokaryotic and eukaryotic cells exhibit all seven characteristics of life.

<p>True</p> Signup and view all the answers

What are organelles?

<p>Smaller structures within cells that carry out life functions.</p> Signup and view all the answers

What is NOT a function of organelles?

<p>Generate electrical signals</p> Signup and view all the answers

What organelle is responsible for converting energy stored in food into usable energy for the cell?

<p>Mitochondria</p> Signup and view all the answers

What organelle creates proteins?

<p>Ribosomes</p> Signup and view all the answers

What is the endoplasmic reticulum, and what is its function?

<p>A network of flat tubes that transport proteins within the cell.</p> Signup and view all the answers

What is the role of the Golgi body?

<p>Sorts and packages proteins into vesicles</p> Signup and view all the answers

What are vesicles?

<p>Small packages containing proteins, nutrients, and water.</p> Signup and view all the answers

What is the function of vacuoles?

<p>Temporary storage areas.</p> Signup and view all the answers

What is the function of lysosomes?

<p>Breakdown of food particles</p> Signup and view all the answers

What organelle is responsible for photosynthesis?

<p>Chloroplasts</p> Signup and view all the answers

Photosynthesis occurs in plant cells.

<p>True</p> Signup and view all the answers

Study Notes

Microorganisms and Cells

  • Microbes: Organisms too small to be seen without a microscope (<1mm)
  • Bacteria in the Mouth: Around 700 species; some cause tooth decay, others compete with harmful ones for survival.
  • Soil Microbes: Decompose dead materials and enhance plant growth by fixing nitrogen.
  • Protists: Single-celled organisms, often found in freshwater.
  • Pathogens: Microbes that cause disease.

Disease Transmission

  • Routes of Transmission: Direct contact, indirect contact, water/food, animal bites

Body's Defenses

  • Physical Barriers: Skin, sweat (oils), mucus membranes (lining nose), tears, eyelashes, ear wax.
  • Inflammation: Increased blood flow to infection site.
  • Fever: High temperature can kill viruses.
  • White Blood Cells: Ingest and destroy invaders.

Characteristics of Life

  • Seven Characteristics: Made of cells, acquire nutrients, need energy, produce waste, respond to stimuli, grow, and reproduce.
  • Spontaneous Generation: Historically thought life arose from non-living matter.
  • Cell Theory: Defines living things as having:
    • One or more cells
    • All cells come from other living cells
    • The cell is the basic unit of life.

Viruses and Microscopes

  • Viruses: Microscopic entities, only visible using electron microscopes. Consist essentially of DNA/RNA and a protective protein coat.
  • Reproduction: Viruses reproduce by invading host cells.

Cell Types

  • Unicellular: Organisms with one cell.
  • Multicellular: Organisms with more than one cell.
  • Prokaryotic Cells: Simple, small cells without a nucleus or membrane-bound organelles (e.g., bacteria).
  • Eukaryotic Cells: Larger, complex cells with a nucleus and membrane-bound organelles (e.g., animal/plant cells).

Cell Organelles

  • Organelles: Specialized structures within cells carrying out life functions. - Provide structure and form, act as barriers, build/repair, store/release energy, and eliminate waste. - Increasing in number as cells grow and function
  • Cell Membrane: Thin, flexible layer surrounding the cell.
  • Nucleus: Cell's control center.
  • Cytoplasm: Gel-like fluid filling the cell where organelles are located.
  • Mitochondria: Produce usable energy for cell functions.
  • Ribosomes: Synthesize proteins.
  • Endoplasmic Reticulum: Transports proteins within the cell.
  • Golgi Body: Modifies, sorts, and packages proteins.
  • Vesicles: Membrane-bound packages of proteins, nutrients, and water.
  • Vacuoles: Temporary storage spaces.
  • Lysosomes: Contain digestive enzymes for breaking down materials.
  • Chloroplasts: Involved in photosynthesis; only in plant cells.

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Description

Explore the fascinating world of microorganisms, from bacteria in the mouth to soil microbes that enhance plant growth. This quiz also covers how diseases are transmitted and the body's defenses against pathogens. Test your knowledge on the seven characteristics of life and the role of microbes in health.

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