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What surrounds the organelles in a cell?
What surrounds the organelles in a cell?
Where are many chemical reactions within a cell typically located?
Where are many chemical reactions within a cell typically located?
What provides the building blocks for cell maintenance, structure, function, and growth?
What provides the building blocks for cell maintenance, structure, function, and growth?
Which specialized structures are found within a cell?
Which specialized structures are found within a cell?
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What is usually released by the chemical reactions in the cytosol?
What is usually released by the chemical reactions in the cytosol?
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What is phagocytosis primarily responsible for?
What is phagocytosis primarily responsible for?
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Which two main types of cells are involved in phagocytosis?
Which two main types of cells are involved in phagocytosis?
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In the process of phagocytosis, what structure is formed after the plasma membrane extends pseudopods to envelope the microbe?
In the process of phagocytosis, what structure is formed after the plasma membrane extends pseudopods to envelope the microbe?
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What happens to the microbe after a lysosome fuses with the phagosome?
What happens to the microbe after a lysosome fuses with the phagosome?
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What is the final result of the phagocytosis process?
What is the final result of the phagocytosis process?
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What are cilia?
What are cilia?
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What is the function of flagella?
What is the function of flagella?
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Which of the following cells typically have flagella?
Which of the following cells typically have flagella?
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How do cilia differ from flagella in terms of length?
How do cilia differ from flagella in terms of length?
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Which of the following best describes the movement of cilia?
Which of the following best describes the movement of cilia?
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What is the primary function of ribosomes?
What is the primary function of ribosomes?
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What type of RNA do ribosomes contain in large amounts?
What type of RNA do ribosomes contain in large amounts?
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Where are ribosomes commonly attached?
Where are ribosomes commonly attached?
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Which cellular process are ribosomes directly involved in?
Which cellular process are ribosomes directly involved in?
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Which of the following statements about ribosomes is true?
Which of the following statements about ribosomes is true?
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Which protein is a component of microfilaments?
Which protein is a component of microfilaments?
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What is the primary role of intermediate filaments?
What is the primary role of intermediate filaments?
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Where are microtubules located within the cell?
Where are microtubules located within the cell?
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Which protein makes up the structure of microtubules?
Which protein makes up the structure of microtubules?
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Which type of cytoskeletal filament is most associated with the cell membrane?
Which type of cytoskeletal filament is most associated with the cell membrane?
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What is the main purpose of microfilaments in cells?
What is the main purpose of microfilaments in cells?
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Which process involves materials moving into a cell in a vesicle?
Which process involves materials moving into a cell in a vesicle?
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What is the correct term for a small spherical sac formed by budding off from a membrane?
What is the correct term for a small spherical sac formed by budding off from a membrane?
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Which process combines endocytosis and exocytosis?
Which process combines endocytosis and exocytosis?
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Which type of endocytosis involves the ingestion of liquid into a cell by the budding of small vesicles?
Which type of endocytosis involves the ingestion of liquid into a cell by the budding of small vesicles?
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In which process do vesicles fuse with the plasma membrane to release their contents into the extracellular fluid?
In which process do vesicles fuse with the plasma membrane to release their contents into the extracellular fluid?
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What is the role of secondary active transport mechanisms?
What is the role of secondary active transport mechanisms?
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What do antiporters do?
What do antiporters do?
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Which ions are often involved in establishing the gradients used in secondary active transport?
Which ions are often involved in establishing the gradients used in secondary active transport?
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In the context of secondary active transport using symporters, which of the following is moved into the cell along with Na+?
In the context of secondary active transport using symporters, which of the following is moved into the cell along with Na+?
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What is hydrolyzed to indirectly provide energy for secondary active transport mechanisms?
What is hydrolyzed to indirectly provide energy for secondary active transport mechanisms?
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What direction does Ca2+ move relative to the concentration gradient in the primary example of antiporters?
What direction does Ca2+ move relative to the concentration gradient in the primary example of antiporters?
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What triggers the fusion of synaptic vesicles with the presynaptic membrane during exocytosis?
What triggers the fusion of synaptic vesicles with the presynaptic membrane during exocytosis?
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Which channels open in response to the nerve impulse in the presynaptic membrane?
Which channels open in response to the nerve impulse in the presynaptic membrane?
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During exocytosis, what occurs immediately after the nerve impulse reaches the synaptic end bulb?
During exocytosis, what occurs immediately after the nerve impulse reaches the synaptic end bulb?
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What is the final step in the exocytosis process at the synapse?
What is the final step in the exocytosis process at the synapse?
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Which event causes ligand-gated channels to open on the postsynaptic neuron?
Which event causes ligand-gated channels to open on the postsynaptic neuron?
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What results from the flow of ions through ligand-gated channels in the postsynaptic neuron?
What results from the flow of ions through ligand-gated channels in the postsynaptic neuron?
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Which neuron is responsible for releasing the neurotransmitter in the synaptic cleft?
Which neuron is responsible for releasing the neurotransmitter in the synaptic cleft?
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What is the role of neurotransmitter binding to receptors on the postsynaptic neuron?
What is the role of neurotransmitter binding to receptors on the postsynaptic neuron?
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What happens first in receptor-mediated endocytosis?
What happens first in receptor-mediated endocytosis?
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Which particle is recognized and bound by receptor proteins in receptor-mediated endocytosis?
Which particle is recognized and bound by receptor proteins in receptor-mediated endocytosis?
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What structure forms on the cytosolic side of the membrane during receptor-mediated endocytosis?
What structure forms on the cytosolic side of the membrane during receptor-mediated endocytosis?
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After the clathrin-coated vesicle forms, what is the next step?
After the clathrin-coated vesicle forms, what is the next step?
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In receptor-mediated endocytosis, what is the fate of LDL particles after fusion with an endosome?
In receptor-mediated endocytosis, what is the fate of LDL particles after fusion with an endosome?
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During receptor-mediated endocytosis, what is the role of the receptors after they are internalized?
During receptor-mediated endocytosis, what is the role of the receptors after they are internalized?
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What process is depicted by the cell engulfing extracellular fluid?
What process is depicted by the cell engulfing extracellular fluid?
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Which of the following is not involved in bulk-phase endocytosis?
Which of the following is not involved in bulk-phase endocytosis?
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What occurs immediately after the vesicle containing extracellular fluid is formed?
What occurs immediately after the vesicle containing extracellular fluid is formed?
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What role do lysosomal enzymes play in pinocytosis?
What role do lysosomal enzymes play in pinocytosis?
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What is released into the cell cytoplasm after the digestion of fluid in pinocytosis?
What is released into the cell cytoplasm after the digestion of fluid in pinocytosis?
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Study Notes
Secondary Active Transport Mechanisms
- Use energy stored in Na+ or H+ concentration gradients to drive transport of other solutes against their concentration gradients
- These gradients are already established by primary active transport
- Indirectly use energy from ATP hydrolysis
Antiporters
- Carry two substances across the membrane in opposite directions
- Use Na+ gradients for transport, e.g., Ca2+ out of the cell, Na+ into the cell
Symporters
- Carry two substances across the membrane in the same direction
- Use Na+ gradients for transport, e.g., glucose into the cell, Na+ into the cell
Phagocytosis
- Form of endocytosis where cells engulf large particles like viruses, bacteria, or dead cells
- Involves macrophages and neutrophils
- Process:
- Microbe attaches to receptor on cell membrane
- Plasma membrane extends pseudopods that envelope the microbe, forming a phagosome
- Lysosome fuses with the phagosome, and digestive enzymes break down the microbe
- Digested products are released from the cell
Ribosomes
- Sites of protein synthesis
- Contain large amounts of ribosomal RNA (rRNA)
- Attached to outer surface of nuclear membrane and Endoplasmic Reticulum
Cytoplasm
- Contains:
- Cytosol (intracellular fluid surrounding organelles)
- Organelles (specialized structures within the cell)
Exocytosis
- Releases materials from cells
- Important for neurotransmitter signaling
- Steps:
- Nerve impulse travels down presynaptic neuron
- Ca2+ influx triggers synaptic vesicles to fuse with presynaptic membrane
- Neurotransmitter is released into the synaptic cleft
- Neurotransmitter binds to receptors on postsynaptic neuron
- Ligand-gated channels open, allowing ions to flow across the postsynaptic membrane
Cilia and Flagella
- Motile projections of the cell surface
- Cilia: short, hair-like projections that move fluids along a cell surface
- Flagella: longer, move an entire cell (e.g., sperm cell's tail)
Cytoskeleton
- Network of protein filaments throughout the cytosol
- Provides structural support for the cell
- Three types:
- Microfilaments (actin, associated with cell membrane and inside the cell)
- Intermediate Filaments (keratin or other proteins, around nucleus)
- Microtubules (tubulin, throughout the cell, attached to centrosome)
Vesicular Transport
- Vesicle: small spherical sac formed by budding off from a membrane
- Endocytosis: materials move into a cell in a vesicle
- Receptor-mediated endocytosis
- Phagocytosis
- Bulk-phase endocytosis (pinocytosis)
- Exocytosis: vesicles fuse with the plasma membrane, releasing their contents
- Transcytosis: combination of endocytosis and exocytosis
Bulk-phase Endocytosis (Pinocytosis)
- No receptor proteins involved
- Transport of extracellular fluid
- Process:
- Cell membrane invaginates, forming a pocket surrounding the fluid
- Pocket pinches off, creating a vesicle with the fluid
- Lysosome fuses with the vesicle
- Lysosome enzymes digest the fluid
- Digested solutes are released into the cell cytoplasm
Receptor-mediated Endocytosis
- Binding: LDL particle binds to a receptor on the plasma membrane
- Invagination: receptor-LDL complex internalized, forming a clathrin-coated pit
- Vesicle formation: clathrin-coated pit pinches off, forming a clathrin-coated vesicle
- Uncoating: clathrin coat is removed
- Fusion with endosome: uncoated vesicle fuses with an endosome
- Recycling: receptor proteins are recycled back to the plasma membrane
- Degradation: LDL particle is degraded in a lysosome
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Description
Learn about secondary active transport mechanisms, which use energy stored in concentration gradients to drive transport of other solutes against their concentration gradients.
