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Questions and Answers
All microbes are harmful and can cause diseases.
False
Microbes are only associated with life-threatening diseases.
False
Some microbes can be used to produce antibiotics that fight harmful bacteria.
True
Microbes only contribute to the spread of diseases and have no positive impact on human health.
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The role of microbes in the environment is limited to causing diseases.
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The cell membrane is also known as the cytoplasm
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All organelles are found in eukaryotic cells
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The nucleus is responsible for generating energy for the cell
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Prokaryotes have a true nucleus
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Eukaryotes are typically smaller in size than prokaryotes
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The cell membrane is impermeable to all substances
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Lysosomes are responsible for protein synthesis
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The endoplasmic reticulum is involved in protein modification and transport
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Study Notes
Cell Membrane
- Known as the plasma membrane, it surrounds and protects the cell.
- Composed of a phospholipid bilayer with hydrophilic (water-attracting) heads and hydrophobic (water-repelling) tails.
- Contains both integral proteins (embedded within the membrane) and peripheral proteins (attached to the surface).
- Functions include regulating nutrient entry and waste exit, maintaining cell shape, and providing mechanical support.
- Selectively permeable, allowing specific substances to pass while blocking others, contributing to homeostasis.
- Flexible yet semi-rigid, enabling the membrane to change shape without losing structural integrity.
Organelles
- Specialized structures found within eukaryotic cells, each performing distinct functions critical for cell survival.
- Nucleus contains the cell's genetic blueprint (DNA) and governs cellular activities.
- Mitochondria serve as powerhouses, generating cellular energy via cellular respiration.
- Endoplasmic reticulum (ER) plays a key role in synthesizing and transporting proteins.
- Ribosomes are the sites where proteins are synthesized, essential for cell function.
- Lysosomes house digestive enzymes to break down waste materials and foreign entities.
- Golgi apparatus modifies, packages, and distributes proteins and lipids for use within or outside the cell.
- Together, organelles maintain cellular homeostasis and execute various functions.
Prokaryotes vs Eukaryotes
- Prokaryotes*
- Unicellular organisms characterized by the absence of a true nucleus.
- Typically small, ranging from 0.5 to 5.0 μm in diameter, with a simplistic structure lacking membrane-bound organelles.
- Genetic material consists of a single circular chromosome.
- Known for rapid reproduction and growth, often found in extreme environments like high temperatures or salinity.
- Examples include bacteria and archaea.
- Eukaryotes*
- Can be unicellular or multicellular and possess a true nucleus encasing their genetic material.
- Generally larger than prokaryotes, ranging from 10 to 30 μm in diameter, featuring a complex structure with membrane-bound organelles.
- Contain linear chromosomes, facilitating more complex regulatory processes.
- Exhibit slower reproduction and growth rates compared to prokaryotes.
- Found in diverse environments, represented by animals, plants, fungi, and protists.
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Description
Explore the dual role of microbes in sustaining life and causing diseases. Learn about the benefits and risks associated with these tiny organisms.
