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Questions and Answers
What is the process called when molecules are transported across the cell membrane without expending energy?
What is the process called when molecules are transported across the cell membrane without expending energy?
Negative feedback mechanisms serve to speed up a cellular process.
Negative feedback mechanisms serve to speed up a cellular process.
False
What is homeostasis?
What is homeostasis?
The internal balance within the systems of living organisms that must be kept stable to maintain life.
The diffusion of water molecules through a ______ membrane is known as osmosis.
The diffusion of water molecules through a ______ membrane is known as osmosis.
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Match each type of feedback with its description:
Match each type of feedback with its description:
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What term is used for a solution whose solute concentration is greater than that of the cytoplasm in a cell?
What term is used for a solution whose solute concentration is greater than that of the cytoplasm in a cell?
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Osmosis is a type of active transport.
Osmosis is a type of active transport.
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What is the primary difference between active transport and passive transport?
What is the primary difference between active transport and passive transport?
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Facilitated diffusion requires special ________ to transport substances across a cell membrane.
Facilitated diffusion requires special ________ to transport substances across a cell membrane.
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Match the types of transport with their descriptions:
Match the types of transport with their descriptions:
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Which of the following describes a hypotonic solution?
Which of the following describes a hypotonic solution?
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Isotonic solutions cause no net movement of water into or out of cells.
Isotonic solutions cause no net movement of water into or out of cells.
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List one of the four factors that determine whether a particle can be passively transported across a cell membrane.
List one of the four factors that determine whether a particle can be passively transported across a cell membrane.
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Study Notes
Cytology
- Cytology is the study of cells.
The Cell Environment
- Homeostasis is the internal balance within living organisms. Homeostasis must be kept stable to maintain life.
- Dynamic equilibrium is the balance of changes and motions in a system.
- The range of tolerance shows the optimal range for a system. Temperature is an example of how a system can be in balance.
- Extreme temperatures can cause death in an organism. Goldfish can not survive in the ocean.
Objectives of 5.2
- Describe how cells maintain homeostasis in different environments.
- Compare how different solutions affect cells.
- Explain how molecules move across the cell membrane.
Getting Feedback
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Positive feedback happens when a substance involved in a cellular process speeds up the process.
- Example: Breathing in oxygen causes hemoglobin to pick up more oxygen in the blood (positive feedback loop).
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Negative feedback happens when a substance produced by a cellular process that slows down the process or stops the process.
- Example: ATP production regulating PFK enzyme (negative feedback loop).
Osmosis
- Osmosis is the diffusion of water molecules through a semipermeable membrane.
- A semipermeable membrane is a membrane that allows certain substances to pass through but not others.
- Different solutions affect cells in different ways (hypotonic, hypertonic, and isotonic)
- Water flows from areas of low concentration to areas of high concentration. A semipermeable membrane is involved in the change.
Types of Solutions
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Hypertonic solution - solute concentration is greater than the cell's cytoplasm. Water moves out of the cell, and the cell shrinks/shrivels.
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Example: Ocean water.
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Hypotonic solution - solute concentration is less than the cell's cytoplasm. Water moves into the cell and the cell swells.
- Example: Pure water.
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Isotonic solution - solute concentration is equal to the cell's cytoplasm. Water moves equally in and out of the cell.
- Example: Red blood cells and plasma.
Passive and Active Transport
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Passive transport: The movement of molecules across a membrane without requiring chemical energy.
- Different types of passive transport include:
- Diffusion: Movement of particles from high to low concentration.
- Osmosis: The diffusion of water.
- Facilitated diffusion: Movement of particles from high to low concentration using special transport proteins embedded in the membrane.
- Different types of passive transport include:
-
Active transport: The movement of molecules across a membrane that uses chemical energy. It moves particles from low concentration to high concentration.
- Different Types of Active Transport include:
- Endocytosis: A cell engulfing a particle, forming a vesicle.
- Exocytosis: A vesicle releases its contents outside the cell.
- Different Types of Active Transport include:
Passive Transport Factors
- Four factors that determine whether a particle can be passively transported are:
- Particle size
- Particle shape
- Particle polarity
- Membrane composition
Passive Transport Methods
- Diffusion
- Osmosis
- Facilitated diffusion
Active transport
- Endocytosis
- Exocytosis
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Description
Test your knowledge on cytology and the mechanisms of homeostasis. This quiz covers how cells interact with their environment, the importance of balance within living organisms, and the effects of different solutions on cells. Prepare to dive into the fascinating world of cellular processes and feedback systems!
