Biology Chapter 5: The Working Cell Flashcards

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Questions and Answers

What does the term 'fluid mosaic' describe?

Protein function

Membrane structure (correct)

Phospholipid composition

Cell structure

What is selective permeability?

A property of biological membranes that allows some substances to cross more easily than others.

Define diffusion.

The spontaneous movement of a substance down its concentration gradient.

What is a concentration gradient?

A region in which the density of a chemical substance increases or decreases. Signup and view all the answers

What is passive transport?

The diffusion of a substance across a biological membrane without energy expenditure. Signup and view all the answers

Define osmosis.

The diffusion of water across a selectively permeable membrane. Signup and view all the answers

What does tonicity refer to?

The ability of a solution surrounding a cell to cause that cell to gain or lose water. Signup and view all the answers

What does isotonic mean?

Referring to a solution that has no effect on the passage of water into or out of a cell. Signup and view all the answers

What is hypotonic?

A solution that causes a cell to take up water. Signup and view all the answers

What does hypertonic refer to?

A solution that causes a cell to lose water. Signup and view all the answers

What is osmoregulation?

The homeostatic maintenance of solute concentrations and the balance of water gain and loss. Signup and view all the answers

Define facilitated diffusion.

The passage of a substance through a specific transport protein across a biological membrane down its concentration gradient. Signup and view all the answers

What is an aquaporin?

A transport protein that facilitates the diffusion of water across the membrane. Signup and view all the answers

Define active transport.

The movement of a substance against its concentration gradient, requiring energy. Signup and view all the answers

What is exocytosis?

The movement of materials out of a cell by fusion of vesicles with the plasma membrane. Signup and view all the answers

Define endocytosis.

Cellular uptake of molecules or particles via vesicle formation. Signup and view all the answers

What is phagocytosis?

Cellular 'eating'; a type of endocytosis where a cell engulfs particles. Signup and view all the answers

What does pinocytosis refer to?

Cellular 'drinking'; a type of endocytosis involving fluid uptake. Signup and view all the answers

What is receptor-mediated endocytosis?

The movement of specific molecules into a cell via vesicles with receptor proteins. Signup and view all the answers

Define energy.

The capacity to cause change, especially to perform work. Signup and view all the answers

What is kinetic energy?

The energy of motion. Signup and view all the answers

Define heat in terms of energy.

Thermal energy associated with the movement of atoms and molecules. Signup and view all the answers

What is potential energy?

The energy that matter possesses because of its position or arrangement. Signup and view all the answers

Define chemical energy.

Energy available in molecules for release in a chemical reaction. Signup and view all the answers

What is thermodynamics?

The study of energy transformation in matter. Signup and view all the answers

What is the first law of thermodynamics?

The principle of conservation of energy. Signup and view all the answers

Define entropy.

A measure of disorder in a system. Signup and view all the answers

What is the second law of thermodynamics?

The principle stating that energy conversions reduce order, increasing entropy. Signup and view all the answers

Define cellular respiration.

The aerobic harvesting of energy from food molecules. Signup and view all the answers

What is an exergonic reaction?

An energy-releasing chemical reaction. Signup and view all the answers

Define endergonic reaction.

An energy-requiring chemical reaction yielding products with more potential energy. Signup and view all the answers

What is metabolism?

The totality of an organism's chemical reactions. Signup and view all the answers

Define metabolic pathway.

A series of chemical reactions that build or break down molecules. Signup and view all the answers

What is energy coupling?

Using energy from an exergonic reaction to drive an endergonic reaction. Signup and view all the answers

What does ATP stand for?

Adenosine triphosphate. Signup and view all the answers

What is phosphorylation?

The production of ATP by chemiosmosis during photosynthesis. Signup and view all the answers

Define activation energy.

The amount of energy required to start a chemical reaction. Signup and view all the answers

What are enzymes?

Biological catalysts that speed up chemical reactions. Signup and view all the answers

Define substrate.

The specific substance on which an enzyme acts. Signup and view all the answers

What is the active site?

The part of an enzyme where a substrate molecule attaches. Signup and view all the answers

What is induced fit?

The change in shape of an enzyme's active site upon substrate binding. Signup and view all the answers

Define cofactors.

Nonprotein molecules or ions required for enzyme function. Signup and view all the answers

What is a coenzyme?

An organic molecule serving as a cofactor. Signup and view all the answers

Define competitive inhibitor.

A substance that reduces enzyme activity by mimicking the substrate. Signup and view all the answers

What is a noncompetitive inhibitor?

A substance that reduces enzyme activity without binding to the active site. Signup and view all the answers

What is feedback inhibition?

A method of metabolic control where a product inhibits an enzyme in the pathway. Signup and view all the answers

Study Notes

Membrane Structure and Transport

Fluid Mosaic Model: Describes the membrane as a diverse mosaic of protein molecules within a fluid phospholipid bilayer.
Selective Permeability: Membranes allow some substances to cross while blocking others, essential for cell function.
Diffusion: Spontaneous movement from a region of higher concentration to one of lower concentration.
Concentration Gradient: Indicates how the density of a substance varies in space; cells maintain gradients to facilitate movement.
Passive Transport: Movement of substances across membranes without energy expenditure, relying on concentration gradients.
Osmosis: Diffusion of water through a selectively permeable membrane.
Tonicity: Influences whether cells gain or lose water based on surrounding solution concentrations.

Solution Types

Isotonic: No net water movement as solute concentrations are equal inside and outside the cell.
Hypotonic: Surrounding solution causes cells to gain water, potentially leading to swelling.
Hypertonic: Surrounding solution results in water loss from the cell, causing it to shrink.

Cellular Processes

Osmoregulation: Maintaining solute balance and regulating water gain/loss within cells.
Facilitated Diffusion: Requires specific transport proteins for substances to move across membranes down their concentration gradients.
Aquaporins: Specialized transport proteins that enhance water movement across cell membranes.

Active Transport Mechanisms

Active Transport: Moves substances against their gradient, requiring energy input (ATP).
Exocytosis: Process of expelling materials from a cell via vesicle fusion with the plasma membrane.
Endocytosis: Uptake of substances through vesicle formation from the plasma membrane, including types like phagocytosis and pinocytosis.
Receptor-Mediated Endocytosis: Specific uptake of molecules via vesicles organized around receptor-protein complexes.

Energy Concepts

Energy: Capacity to perform work or cause change.
Kinetic Energy: Energy of motion; relates to moving objects.
Potential Energy: Energy stored due to position or arrangement; includes chemical bonds and gravitational potential.
Thermodynamics: Study of energy transformations in matter.

Laws of Thermodynamics

First Law: Energy conservation; energy can’t be created or destroyed, only transformed.
Entropy: A measure of disorder; increases with energy transformations, mirroring the second law.
Second Law: Every energy conversion results in increased entropy, implying a reduction in order.

Metabolism and Reactions

Cellular Respiration: Aerobic breakdown of food to liberate energy usable by cells.
Metabolism: Total chemical reactions in an organism, encompassing both energy-releasing and energy-consuming pathways.
Energy Coupling: Utilizes energy from exergonic reactions to fuel endergonic reactions.

ATP and Reactions

ATP: Main energy currency of cells; provides energy for various biological processes.
Enzymes: Biological catalysts that accelerate chemical reactions without being consumed.
Activation Energy: Minimum energy required for reactants to start a chemical reaction.
Substrate: Specific reactant on which an enzyme acts, with each enzyme having unique substrates.

Enzyme Functionality

Active Site: Region on an enzyme where substrates bind, critical for catalysis.
Induced Fit Model: Enzyme dynamically alters its shape upon substrate binding for optimal interaction.
Cofactors and Coenzymes: Additional nonprotein molecules or organic compounds needed for enzyme activity; vitamins often serve as coenzymes.
Inhibitors: Molecules that decrease enzyme activity; competitive inhibitors block active sites, while noncompetitive inhibitors alter enzyme structure without engaging active sites.
Feedback Inhibition: A regulatory mechanism where the end product of a pathway inhibits an enzyme within that pathway, helping maintain homeostasis.

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Description

Test your knowledge on key concepts from Biology Chapter 5 with these flashcards. The focus is on important terms such as 'fluid mosaic' and 'selective permeability'. Enhance your understanding of membrane structures and functions in cells.