Questions and Answers
What is the main site of adenosine triphosphate (ATP) production within cells?
What is the function of the cytoskeleton in a cell?
What is the role of ATP in a cell?
What is the material within the inner membrane of a mitochondrion?
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What is the main function of leak channels in the cell membrane?
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What is the series of chemical reactions that require O2 to break down food molecules to produce ATP?
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What type of protein structures make up the cytoskeleton?
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How do gated channels differ from leak channels?
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What is the direction of water movement in osmosis?
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What is the purpose of osmotic pressure?
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What would happen to a cell if it experiences large volume changes due to water movement?
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What is the role of the selectively permeable membrane in osmosis?
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What type of channel is always open, allowing ions to pass through the membrane?
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Why is osmosis important to cells?
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Where are ribosomal subunits produced?
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What is the main function of rough ER?
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Where do ribosomal subunits move to after being produced in the nucleus?
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What is the characteristic of smooth ER?
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What is the function of smooth ER in skeletal muscle cells?
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What is the relationship between the endoplasmic reticulum and the nuclear envelope?
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What is the structure of the endoplasmic reticulum?
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What is the difference between rough ER and smooth ER?
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What is the primary function of DNA in a cell?
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What is the overall structure of a DNA molecule?
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What is the bonding pattern between nucleotides on opposite strands?
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What is the primary function of a carrier molecule in the context of glucose transport?
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What is the role of a gene in protein synthesis?
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What is the composition of a nucleotide?
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Which of the following statements about active transport is true?
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What is the result of DNA directing protein synthesis?
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What is the direction of substance movement in active transport?
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What is the role of proteins synthesized from DNA instructions?
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What is the purpose of the sodium-potassium pump in active transport?
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What is the energy requirement for active transport?
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What is the significance of DNA in an organism?
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What is the result of active transport in terms of concentration gradients?
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What is the difference between active transport and passive transport?
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What is the role of a carrier molecule in active transport?
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Study Notes
Cell Membrane Channels
- Leak channels constantly allow ions to pass through the cell membrane.
- Gated channels limit the movement of ions across the membrane by opening and closing.
Osmosis
- Osmosis is the diffusion of water across a selectively permeable membrane from a region of higher water concentration to one of lower water concentration.
- Osmosis exerts a pressure, termed osmotic pressure, which is the force required to prevent movement of water across the cell membrane.
- Osmosis is important to cells because large volume changes caused by water movement can disrupt normal cell functions.
Active Transport
- Active transport is a carrier-mediated process that requires ATP to move substances across the cell membrane from regions of lower concentration to those of higher concentration against a concentration gradient.
- Active transport accumulates necessary substances on one side of the cell membrane at concentrations many times greater than those on the other side.
Endoplasmic Reticulum (ER)
- The endoplasmic reticulum (ER) is a series of membranes forming sacs and tubules that extends from the outer nuclear membrane into the cytoplasm.
- Rough ER is involved in protein synthesis and is rough due to attached ribosomes.
- Smooth ER has no attached ribosomes and is a site for lipid synthesis, cellular detoxification, and it stores calcium ions in skeletal muscle cells.
Mitochondria
- Mitochondria are major sites of adenosine triphosphate (ATP) production within cells.
- Mitochondria carry out aerobic respiration, a series of chemical reactions that require O2 to break down food molecules to produce ATP.
- ATP is the main energy source for most chemical reactions within the cell, and cells with a large energy requirement have more mitochondria than cells that require less energy.
Cytoskeleton
- The cytoskeleton gives internal framework to the cell.
- The cytoskeleton consists of protein structures that support the cell, hold organelles in place, and enable the cell to change shape.
- The protein structures of the cytoskeleton are microtubules, microfilaments, and intermediate filaments.
DNA
- DNA contains the information that directs protein synthesis; a process called gene expression.
- A DNA molecule consists of nucleotides joined together to form two nucleotide strands.
- Each nucleotide consists of a 5-carbon sugar, a phosphate group, and a nitrogenous base.
- A gene is a sequence of nucleotides that provides a chemical set of instructions for making a specific protein.
- DNA influences the structural and functional characteristics of the entire organism because it directs protein synthesis.
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Description
This quiz covers the two main classes of cell membrane channels, including leak channels and gated channels. It explores how they function and allow ions to pass through.