Questions and Answers
Who is known for the development of the microscope and observing cells?
Robert Hooke
What is the basic unit of life?
All living things are composed of one or more cells.
True
The cell membrane is _____ permeable.
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What is the function of the cytoplasm?
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What are the folds in mitochondria called?
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What type of transport requires cellular energy?
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Match the following types of solutions with their descriptions:
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What is the primary function of ribosomes?
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Study Notes
Cells as Building Blocks of Life
- Cells form the foundation of all living organisms; they are essential for structure and function.
- The cell membrane is semi-permeable, composed of a phospholipid bilayer with hydrophilic heads and hydrophobic tails, incorporating proteins.
- Cytoplasm contains organelles and cell components, facilitating metabolic processes and providing structure.
- The nucleus acts as the information center of the cell, housing DNA and regulating gene expression.
- The cell cycle describes the stages through which a cell goes, including growth, DNA replication, and division.
Types of Cells
- Animal cells perform various functions such as protection, support, movement, metabolism, communication, and energy release.
Unified Cell Theory
- Cells are the fundamental units of life.
- All living organisms consist of one or more cells.
- Cells originate from pre-existing cells through the process of division.
Cell Membrane
- The fluid mosaic model illustrates the dynamic nature of cell membranes, which contain embedded proteins that play a role in transport and communication.
Movement Across Membranes
- The cell membrane selectively permits substances to enter or exit, with mechanisms including active and passive transport.
- Active transport requires energy to move substances against a concentration gradient, typically involving ions and small molecules.
- Passive transport occurs naturally, allowing substances to move from areas of high to low concentration without energy expenditure.
Passive Transport Mechanisms
- Diffusion: Movement of substances from high to low concentration until equilibrium is achieved.
- Facilitated transport: Involves membrane proteins aiding the passive movement of substances along a concentration gradient.
- Osmosis: The movement of water through a semipermeable membrane, influenced by solute concentrations.
Tonicity and Osmolarity
- Tonicity describes how surrounding solutions affect cell volume via osmosis:
- Hypotonic: ECF has lower osmolarity than the cytoplasm, leading to cell swelling.
- Hypertonic: ECF has higher osmolarity than the cytoplasm, causing cell shrinkage.
- Isotonic: ECF has the same osmolarity as cytoplasm, no net water movement.
Cytoplasm and Organelles
- The cytoplasm is a semi-fluid matrix that houses organelles, enabling cellular metabolism and transport.
- Mitochondria: Known as the cell's energy factories, responsible for ATP synthesis through cellular respiration.
- Ribosomes: Sites for protein synthesis, found freely in the cytosol or attached to the endoplasmic reticulum (ER).
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Endoplasmic Reticulum (ER):
- Smooth ER: Synthesizes lipids, stores calcium ions, and detoxifies drugs.
- Rough ER: Studded with ribosomes for protein synthesis, serves as an intracellular transport system.
- Golgi Apparatus: Collects, packages, and distributes newly synthesized molecules within the cell.
Cellular Components
- Vacuoles: Serve as storage organelles, holding substances for later use or waste disposal.
- Cellular metabolism involves a range of reactions that are critical for energy production and resource management within the cell.
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Description
This quiz explores the essential concepts in Chapter 2 of General Zoology, focusing on cell structures and their respective functions. It covers topics such as cell membranes, the nucleus, and various types of cells. Test your understanding of how these components contribute to the life processes within organisms.
