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Questions and Answers
What component of the plasma membrane helps maintain its fluidity?
What component of the plasma membrane helps maintain its fluidity?
- Proteins
- Cholesterol (correct)
- Phospholipid bilayer
- Cytoskeleton filaments
Which type of molecules can pass easily through the cell membrane?
Which type of molecules can pass easily through the cell membrane?
- Nonpolar molecules (correct)
- Charged ions
- Large polar molecules
- Small hydrophilic molecules
What results from simple diffusion across a membrane?
What results from simple diffusion across a membrane?
- Movement of molecules from low to high concentration
- Equilibrium of molecules on both sides of the membrane (correct)
- Active transport of solutes using energy
- Formation of new cell membranes
Which of the following describes the role of glycoproteins in the cell membrane?
Which of the following describes the role of glycoproteins in the cell membrane?
How does facilitated diffusion differ from simple diffusion?
How does facilitated diffusion differ from simple diffusion?
What defines 'selectively permeable' in relation to the cell membrane?
What defines 'selectively permeable' in relation to the cell membrane?
What is the primary driving force behind passive transport?
What is the primary driving force behind passive transport?
What do we call the difference in concentration of a substance from one location to another?
What do we call the difference in concentration of a substance from one location to another?
What process involves transporting molecules from low to high concentration with the use of energy?
What process involves transporting molecules from low to high concentration with the use of energy?
Which type of endocytosis is known as 'cell drinking'?
Which type of endocytosis is known as 'cell drinking'?
What is the main function of exocytosis?
What is the main function of exocytosis?
Which example illustrates the process of phagocytosis?
Which example illustrates the process of phagocytosis?
Which of the following substances is typically transported through facilitated diffusion?
Which of the following substances is typically transported through facilitated diffusion?
What distinguishes chloroplasts and mitochondria according to endosymbiotic theory?
What distinguishes chloroplasts and mitochondria according to endosymbiotic theory?
The cell membrane consists of which type of bilayer structure?
The cell membrane consists of which type of bilayer structure?
Which of the following organelles is primarily responsible for protein synthesis?
Which of the following organelles is primarily responsible for protein synthesis?
What happens to a cell placed in a hypertonic solution?
What happens to a cell placed in a hypertonic solution?
Which type of solution causes a cell to swell?
Which type of solution causes a cell to swell?
What is the primary characteristic of active transport?
What is the primary characteristic of active transport?
In which situation would water molecules move from a high concentration of water to low concentration?
In which situation would water molecules move from a high concentration of water to low concentration?
Which of the following correctly describes osmosis?
Which of the following correctly describes osmosis?
What characterizes an isotonic solution?
What characterizes an isotonic solution?
Which of the following examples is associated with active transport?
Which of the following examples is associated with active transport?
What is the net movement of water in a hypotonic solution compared to the cell's cytoplasm?
What is the net movement of water in a hypotonic solution compared to the cell's cytoplasm?
What is the main difference between passive and active transport across the cell membrane?
What is the main difference between passive and active transport across the cell membrane?
Which of the following solutions is classified as hypotonic relative to a cell?
Which of the following solutions is classified as hypotonic relative to a cell?
What are the two main purposes of cell division?
What are the two main purposes of cell division?
Which phase of the cell cycle is crucial for DNA replication?
Which phase of the cell cycle is crucial for DNA replication?
In which type of feedback loop does the response enhance or intensify the original stimulus?
In which type of feedback loop does the response enhance or intensify the original stimulus?
What distinguishes specialized cells from stem cells?
What distinguishes specialized cells from stem cells?
What role do checkpoints play in the regulation of the cell cycle?
What role do checkpoints play in the regulation of the cell cycle?
Which mechanism would the cell most likely use to absorb large particles or cells?
Which mechanism would the cell most likely use to absorb large particles or cells?
The cell membrane is made up of a phospholipid ______.
The cell membrane is made up of a phospholipid ______.
Molecules that can easily pass through the cell membrane are typically ______ molecules.
Molecules that can easily pass through the cell membrane are typically ______ molecules.
In passive transport, molecules move from an area of high ______ to an area of low concentration.
In passive transport, molecules move from an area of high ______ to an area of low concentration.
Facilitated diffusion requires ______ proteins to help transport molecules across the membrane.
Facilitated diffusion requires ______ proteins to help transport molecules across the membrane.
The primary role of cholesterol in the cell membrane is to maintain its ______.
The primary role of cholesterol in the cell membrane is to maintain its ______.
A ______ is a uniform mixture of two or more substances.
A ______ is a uniform mixture of two or more substances.
The ______ gradient describes the difference in concentration of a substance from one location to another.
The ______ gradient describes the difference in concentration of a substance from one location to another.
Water is a ______ molecule that can pass easily through the cell membrane.
Water is a ______ molecule that can pass easily through the cell membrane.
Endocytosis uses vesicles to move large particles into the ___.
Endocytosis uses vesicles to move large particles into the ___.
Phagocytosis is referred to as cell '___'.
Phagocytosis is referred to as cell '___'.
Exocytosis uses vesicles to ___ materials out of the cell.
Exocytosis uses vesicles to ___ materials out of the cell.
Pinocytosis is known as cell '___'.
Pinocytosis is known as cell '___'.
The process of moving molecules from an area of low concentration to an area of high concentration requires ___.
The process of moving molecules from an area of low concentration to an area of high concentration requires ___.
White blood cells use endocytosis to engulf ___ in order to fight infection.
White blood cells use endocytosis to engulf ___ in order to fight infection.
Mitochondria and chloroplasts support the ___ theory, which explains their unique characteristics.
Mitochondria and chloroplasts support the ___ theory, which explains their unique characteristics.
Neurotransmitters are examples of substances transported through facilitated ___.
Neurotransmitters are examples of substances transported through facilitated ___.
Molecules move down a concentration ______, from high [] to low [].
Molecules move down a concentration ______, from high [] to low [].
Water molecules move down a concentration gradient, from high ______ to an area of low ______ until equilibrium is reached.
Water molecules move down a concentration gradient, from high ______ to an area of low ______ until equilibrium is reached.
In a ______ solution, water [] is lower than the cell's cytoplasm, causing the cell to shrivel.
In a ______ solution, water [] is lower than the cell's cytoplasm, causing the cell to shrivel.
In a ______ solution, water [] is higher than the cell's cytoplasm, resulting in the cell swelling.
In a ______ solution, water [] is higher than the cell's cytoplasm, resulting in the cell swelling.
Active transport moves materials from low to high concentration ______ the concentration gradient using energy.
Active transport moves materials from low to high concentration ______ the concentration gradient using energy.
Cells that have a nucleus and membrane-bound organelles are called ______ cells.
Cells that have a nucleus and membrane-bound organelles are called ______ cells.
Molecular pumps allow a cell to concentrate key ______ within the cell, by pumping them across the membrane.
Molecular pumps allow a cell to concentrate key ______ within the cell, by pumping them across the membrane.
The ______ solution has identical water [] to the cell's cytoplasm, therefore the cell stays the same.
The ______ solution has identical water [] to the cell's cytoplasm, therefore the cell stays the same.
In ______ solutions, the concentration of solute is lower outside the cell than inside.
In ______ solutions, the concentration of solute is lower outside the cell than inside.
Osmosis is the simple diffusion of ______ across the cell membrane.
Osmosis is the simple diffusion of ______ across the cell membrane.
The process by which cells take in liquids is known as ______.
The process by which cells take in liquids is known as ______.
The two main purposes for cell division are growth and ______.
The two main purposes for cell division are growth and ______.
In a ______ feedback loop, the response enhances the original stimulus.
In a ______ feedback loop, the response enhances the original stimulus.
The ______ phase is where DNA is replicated in the cell cycle.
The ______ phase is where DNA is replicated in the cell cycle.
Cells that can develop into many different cell types are known as ______ cells.
Cells that can develop into many different cell types are known as ______ cells.
The structure that regulates what enters and exits the cell is called the ______.
The structure that regulates what enters and exits the cell is called the ______.
Study Notes
Cell Membrane
- The cell membrane is the outer bilayer of the cell and plays a crucial role in maintaining homeostasis.
- It is composed of a phospholipid bilayer, cholesterol, cytoskeleton filaments, proteins, glycoproteins, and carbohydrate chains.
- Phospholipid bilayer: two layers of phospholipids, each with a phosphate head and two fatty acid tails.
- Fatty acid tails are nonpolar and hydrophobic, pointing inward.
- Phosphate heads are polar and hydrophilic, pointing outward.
- Cholesterol: helps maintain the fluidity of the membrane.
- Proteins: act as channels or carriers for different molecules and can facilitate diffusion.
- Glycoproteins: act as receptors for signaling molecules.
- Carbohydrate chains: for cell recognition.
Selectively Permeable
- The cell membrane is selectively permeable, allowing some molecules to pass through easily while restricting others.
- Easily pass through:
- Small molecules
- Nonpolar molecules
- Hydrophobic molecules
- Neutral molecules
- Water
- Difficult to pass through:
- Polar molecules
- Large molecules
Words to Know
- Solute: substance that gets dissolved (e.g., lemonade powder).
- Solvent: substance that does the dissolving (e.g., water).
- Solution: uniform mixture of two or more substances (e.g., lemonade).
- Concentration: amount of solute dissolved in a solvent, abbreviated as [ ].
- Concentration gradient: difference in concentration of a substance from one location to another.
Passive Transport
- Passive transport does not require energy, as molecules move from a high concentration area to a low concentration area, following the concentration gradient.
- Examples include simple diffusion, facilitated diffusion, and osmosis.
Simple Diffusion
- Simple diffusion is the spreading out of molecules across a membrane until equilibrium is reached.
- Molecules move down the concentration gradient, from high [ ] to low [ ].
- Examples include O2 and CO2, and other small, nonpolar molecules.
Facilitated Diffusion
- Facilitated diffusion involves a transport protein that helps to facilitate the diffusion of molecules that normally couldn't pass through the cell membrane.
- Transport proteins can act as channels or carriers.
- Molecules move down the concentration gradient, from high [ ] to low [ ].
- Examples include large molecules like glucose (C6H12O6) and polar molecules like calcium (Ca+2).
Osmosis
- Osmosis is the simple diffusion of water across the cell membrane.
- Water molecules move down the concentration gradient, from high [water] to low [water] until equilibrium is reached.
- High [water] indicates low [solute].
- Low [water] indicates high [solute].
Types of Osmosis
- Hypertonic Solution: Water [ ] is lower than the cell's cytoplasm, causing net movement of water out of the cell, leading to cell shrinkage or shriveling.
- Hypotonic Solution: Water [ ] is higher than the cell's cytoplasm, causing net movement of water into the cell, leading to cell swelling.
- Isotonic Solution: Identical water [ ] to cell's cytoplasm, causing no net movement of water and the cell stays the same.
Active Transport
- Active transport requires energy (ATP) to move materials across the membrane against the concentration gradient, from low to high concentration.
- Examples include molecular pumps, exocytosis, and endocytosis.
Molecular Pumps
- Molecular pumps use energy to pump molecules across the membrane, against the [ ] gradient, through a protein channel.
- This allows cells to concentrate key molecules within the cell or remove waste quickly.
- Examples include potassium (K+), chlorine (Cl-), and sodium (Na+).
Using Vesicles
- Endocytosis: uses vesicles to move large particles into the cell (e.g., when white blood cells engulf bacteria).
- Exocytosis: uses vesicles to export materials out of the cell (e.g., when nerve cells secrete neurotransmitters).
2 Types of Endocytosis
- Phagocytosis: Cell "eating" - engulfs solids into vesicles and digests them.
- Pinocytosis: Cell "drinking" - engulfs liquids into vesicles and digests them.
Summary Table
| Type of Transport | Passive/Active | Example of Substances Transported |
|---|---|---|
| Facilitated Diffusion | Active | Neurotransmitters |
| Endocytosis | Active | Captures bacteria |
| Passive | O2 and CO2 | |
| Passive | K+, Na+, Ca2+, Cl- |
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Description
Test your knowledge on the key components and functions of the cell membrane in this quiz focused on cell biology. Explore topics such as diffusion, transport mechanisms, and the roles of glycoproteins and endocytosis. Perfect for students studying cell structure and function.
