Questions and Answers
Which component is NOT primarily found in the plasma membrane?
What is the main function of the glycocalyx?
Which statement about transmembrane proteins is true?
Which of the following comprises the basic framework of the plasma membrane?
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What percentage of the plasma membrane is composed of phospholipids?
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What is the main role of membrane proteins in cells?
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Which of the following statements accurately describes the fluid mosaic model?
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What is the primary purpose of the plasma membrane?
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Which of the following body systems plays a crucial role in obtaining oxygen and eliminating carbon dioxide to maintain homeostasis?
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What is the primary function of the integumentary system in maintaining homeostasis?
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Which of the following is an example of an intrinsic control system?
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Which of the following factors is NOT a parameter that is tightly regulated to maintain homeostasis?
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Which of the following body systems is responsible for breaking down dietary food into small nutrient molecules?
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What is the primary function of the endocrine system in maintaining homeostasis?
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Which of the following is NOT a function of the nervous system in maintaining homeostasis?
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What is the primary function of the reproductive system in maintaining homeostasis?
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Which of the following is NOT a component of the internal environment?
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What is the primary function of the internal environment?
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What percentage of body weight is comprised of extracellular fluid (ECF)?
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Which of the following is an example of transcellular fluid?
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What is the term for the state of constancy of conditions within the body?
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What is the primary function of the epithelial tissue layer?
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What is the term for the fluid environment in which cells live?
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Which of the following is NOT a component of the extracellular fluid?
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What is the primary source of energy used to drive secondary active transport?
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Which type of transport protein carries two substances across the membrane in opposite directions?
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What is the clinical application of Digitalis in relation to heart function?
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What is the process by which a vesicle fuses with the cell membrane to release its contents?
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What is the term for the movement of substances into a cell through a vesicle?
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What is the name of the disease caused by a defective gene that produces an abnormal chloride ion transporter?
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What is the term for the pressure of a solution that is proportional to the concentration of the solute particles that cannot cross the membrane?
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What is the term for the process by which a cell engulfs a solid particle, forming a vesicle?
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What type of proteins act as cellular recognition sites, binding to specific substances?
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Which of the following is a characteristic of the lipid bilayer portion of the plasma membrane?
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What is the primary function of aquaporins in the plasma membrane?
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What is the main difference between primary active transport and other types of transport mechanisms?
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What is the primary purpose of the sodium/potassium ion pump in cells?
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What is the term for the movement of solutes against a concentration gradient, requiring energy from ATP?
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What is the purpose of linker proteins in cells?
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What is the term for the movement of macromolecules across the plasma membrane?
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Study Notes
Introduction to Physiology
- The course covers the cellular level of organization in the human body
- References include Tortora and Derrickson's "Principles of Anatomy and Physiology" and Guyton's "Textbook of Medical Physiology"
Parts of a Cell
- A cell can be divided into three principal parts: plasma membrane, cytoplasm, and nucleus
- Cytoplasm consists of cytosol and organelles (except for the nucleus)
The Plasma Membrane
- The plasma membrane is a flexible, sturdy barrier that surrounds and contains the cytoplasm of the cell
- The fluid mosaic model describes the membrane as consisting of proteins in a sea of lipids
- The lipid bilayer is the basic framework of the plasma membrane, made up of phospholipid molecules with cholesterol and glycolipids scattered among them
Membrane Proteins
- Proteins that stretch across the entire bilayer and project on both sides of the membrane are termed transmembrane proteins
- Glycocalyx is a sugary coat facing the extracellular fluid, composed of glycolipids and glycoproteins
- Glycocalyx enables cells to recognize one another and adhere to each other in some tissues, and protects cells from being digested by enzymes in the extracellular fluid
Functions of Membrane Proteins
- Formation of channels that allow specific substances to pass through
- Transporter proteins that bind to specific substances, change shape, and move them across the membrane
- Receptor proteins that act as cellular recognition sites
- Enzymes that speed up reactions
- Linker proteins that anchor proteins in the cell membrane or to other cells, allowing cell movement, shape, and structure
- Cell identity markers that allow cells to recognize other similar cells
Membrane Permeability
- Plasma membranes are selectively permeable, allowing certain substances to pass through while keeping others out
- The lipid bilayer is permeable to small, nonpolar, uncharged molecules but impermeable to ions and charged or polar molecules
- The membrane is also permeable to water, with aquaporins functioning as water channels
- Transmembrane proteins can increase the permeability of the membrane to certain molecules
- Macromolecules are unable to pass through the plasma membrane except by vesicular transport
Gradients Across Membranes
- Concentration gradients exist across membranes, with higher concentrations of certain substances on one side and lower concentrations on the other
- Electrical gradients also exist, with differences in electrical charge across the membrane
Transport Across the Plasma Membrane
- Active transport is an energy-requiring process that moves solutes against a concentration gradient
- Primary active transport uses energy from ATP to pump substances across the membrane, such as the sodium/potassium ion pump
- Secondary active transport uses energy stored in concentration gradients to drive other substances against their own concentration gradients
- Osmosis is the movement of water from an area of high concentration to an area of low concentration through a selectively permeable membrane
- Tonicity refers to the ability of a solution to cause a cell to swell or shrink
Clinical Applications
- Cystic fibrosis is caused by a defective gene that produces an abnormal chloride ion transporter, affecting various bodily systems
- Digitalis slows the sodium ion-calcium ion antiporters, allowing more calcium to stay inside heart muscle cells and increasing the force of their contraction
Transport in Vesicles
- Materials can enter or leave the cell through vesicle transport
- Endocytosis is the process of bringing materials into the cell, while exocytosis is the release of materials from the cell
Plan of Human Body
- The human body consists of an external environment and internal environment
- The internal environment is the fluid surrounding cells inside the body, also known as the extracellular fluid (ECF)
Body Fluids
- Body fluids consist mostly of water
- The ECF is the internal environment, surrounding cells inside the body
- Body fluids contain ions, oxygen, nutrients, and waste products
Fluid Compartments
- The body has two main fluid compartments: extracellular fluid (ECF) and intracellular fluid (ICF)
- The ECF is divided into plasma, interstitial fluid, and transcellular fluid
- The ICF is the fluid contained within all body cells
Homeostasis
- Homeostasis is the maintenance of a dynamic steady state of the internal environment
- Homeostasis is essential for cell survival
- Factors that are homeostatically regulated include nutrient molecule concentration, gas concentrations, waste product concentration, pH, electrolyte concentration, body fluid volume and vascular pressure, and body temperature
Human Body Systems Contribute to Homeostasis
- Various body systems contribute to homeostasis, including the circulatory, digestive, respiratory, urinary, skeletal, muscular, integumentary, immune, nervous, and endocrine systems
- Each system plays a specific role in maintaining homeostasis, such as transporting materials, breaking down food, obtaining oxygen, removing waste, providing support and protection, and regulating activities.
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Description
This quiz covers essential concepts from the field of physiology, focusing on the cellular level of organization and the components of a cell. It is based on key references including Tortora and Derrickson's 'Principles of Anatomy and Physiology' and Guyton's 'Textbook of Medical Physiology'. Test your understanding of the fundamental mechanisms of body function.
