Cell Membrane Channels: Leak and Gated Channels
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Questions and Answers

What is the main site of adenosine triphosphate (ATP) production within cells?

  • Endoplasmic reticulum
  • Mitochondria (correct)
  • Golgi apparatus
  • Lysosomes

What is the function of the cytoskeleton in a cell?

  • To store genetic information
  • To synthesize proteins
  • To give internal framework to the cell and hold organelles in place (correct)
  • To regulate cell growth

What is the role of ATP in a cell?

  • To store genetic information
  • To synthesize proteins
  • To serve as the main energy source for most chemical reactions (correct)
  • To provide structure to the cell

What is the material within the inner membrane of a mitochondrion?

<p>Mitochondrial matrix (C)</p> Signup and view all the answers

What is the main function of leak channels in the cell membrane?

<p>To constantly allow ions to pass through (B)</p> Signup and view all the answers

What is the series of chemical reactions that require O2 to break down food molecules to produce ATP?

<p>Aerobic respiration (A)</p> Signup and view all the answers

What type of protein structures make up the cytoskeleton?

<p>Microtubules, microfilaments, and intermediate filaments (C)</p> Signup and view all the answers

How do gated channels differ from leak channels?

<p>Gated channels regulate the movement of ions, while leak channels do not (B)</p> Signup and view all the answers

What is the direction of water movement in osmosis?

<p>From a region of higher water concentration to one of lower water concentration (C)</p> Signup and view all the answers

What is the purpose of osmotic pressure?

<p>To prevent movement of water across the cell membrane (C)</p> Signup and view all the answers

What would happen to a cell if it experiences large volume changes due to water movement?

<p>It would disrupt normal cell functions (B)</p> Signup and view all the answers

What is the role of the selectively permeable membrane in osmosis?

<p>To allow the movement of water from a region of higher to lower water concentration (B)</p> Signup and view all the answers

What type of channel is always open, allowing ions to pass through the membrane?

<p>Leak channel (B)</p> Signup and view all the answers

Why is osmosis important to cells?

<p>It helps to maintain normal cell functions (B)</p> Signup and view all the answers

Where are ribosomal subunits produced?

<p>Nucleus (C)</p> Signup and view all the answers

What is the main function of rough ER?

<p>Protein synthesis (A)</p> Signup and view all the answers

Where do ribosomal subunits move to after being produced in the nucleus?

<p>Cytoplasm (D)</p> Signup and view all the answers

What is the characteristic of smooth ER?

<p>Absence of ribosomes (C)</p> Signup and view all the answers

What is the function of smooth ER in skeletal muscle cells?

<p>Storage of calcium ions (C)</p> Signup and view all the answers

What is the relationship between the endoplasmic reticulum and the nuclear envelope?

<p>They are continuous with each other (A)</p> Signup and view all the answers

What is the structure of the endoplasmic reticulum?

<p>A series of sacs and tubules (A)</p> Signup and view all the answers

What is the difference between rough ER and smooth ER?

<p>Rough ER has ribosomes, while smooth ER does not (B)</p> Signup and view all the answers

What is the primary function of DNA in a cell?

<p>To direct protein synthesis (D)</p> Signup and view all the answers

What is the overall structure of a DNA molecule?

<p>Two nucleotide strands connected and twisted around its long axis (A)</p> Signup and view all the answers

What is the bonding pattern between nucleotides on opposite strands?

<p>Specific and complementary (B)</p> Signup and view all the answers

What is the primary function of a carrier molecule in the context of glucose transport?

<p>To transport glucose across the cell membrane from an area of higher concentration to an area of lower concentration (D)</p> Signup and view all the answers

What is the role of a gene in protein synthesis?

<p>To provide a chemical set of instructions for making a specific protein (D)</p> Signup and view all the answers

What is the composition of a nucleotide?

<p>A 5-carbon sugar, a phosphate group, and a nitrogenous base (B)</p> Signup and view all the answers

Which of the following statements about active transport is true?

<p>It accumulates necessary substances on one side of the cell membrane at concentrations many times greater than those on the other side (A)</p> Signup and view all the answers

What is the result of DNA directing protein synthesis?

<p>The influence on the structural and functional characteristics of the entire organism (C)</p> Signup and view all the answers

What is the direction of substance movement in active transport?

<p>Against the concentration gradient (C)</p> Signup and view all the answers

What is the role of proteins synthesized from DNA instructions?

<p>To serve as structural components, be secreted outside the cell, and regulate chemical reactions (A)</p> Signup and view all the answers

What is the purpose of the sodium-potassium pump in active transport?

<p>To pump sodium out of the cell and potassium into the cell (B)</p> Signup and view all the answers

What is the energy requirement for active transport?

<p>ATP is required (D)</p> Signup and view all the answers

What is the significance of DNA in an organism?

<p>It directs protein synthesis and influences the entire organism (B)</p> Signup and view all the answers

What is the result of active transport in terms of concentration gradients?

<p>Substances are accumulated on one side of the cell membrane at concentrations many times greater than those on the other side (A)</p> Signup and view all the answers

What is the difference between active transport and passive transport?

<p>Passive transport moves substances with the concentration gradient, while active transport moves substances against the concentration gradient (D)</p> Signup and view all the answers

What is the role of a carrier molecule in active transport?

<p>To transport substances across the cell membrane (B)</p> Signup and view all the answers

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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Chapter 3 - Cell Structures and Their Function PDF

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.

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