Honors: Cellular Transport & Energy Study Guide

Comprehensive vocabulary flashcards covering cellular energy (photosynthesis, cellular respiration, fermentation) and cellular transport (membrane structure, tonicity, passive and active transport).

Photosynthesis

The cellular process taking place in chloroplasts that absorbs light energy to convert reactants into chemical energy through Light-Dependent and Light-Independent Reactions.

Chloroplast

The plant cell organelle where photosynthesis takes place and where light energy is absorbed.

Light-Dependent Reactions

The stage of photosynthesis occurring in the chloroplast that directly absorbs light energy to drive the initial energy-capturing reactions.

Light-Independent Reactions

The stage of photosynthesis occurring in the chloroplast that uses the chemical energy generated by light-dependent reactions to synthesize carbohydrates without requiring direct sunlight.

Cellular Respiration

The metabolic pathway occurring in cells that converts biochemical energy from nutrients into $ATP$, consisting of Glycolysis, the Krebs cycle, and the Electron Transport Chain.

ATP

The primary energy currency molecule of the cell used to fuel cellular processes and power active transport.

Glycolysis

The initial metabolic pathway of cellular respiration that takes place in the cytoplasm and breaks down glucose to release energy.

Krebs Cycle

A central stage of cellular respiration that breaks down organic molecules to produce electron carriers and energy precursors.

Electron Transport Chain

The final stage of cellular respiration that transfers electrons through membrane-bound carriers to generate the majority of $ATP$.

Fermentation

An anaerobic cellular process that allows energy generation without oxygen, occurring in specific cellular locations through lactic acid or alcoholic pathways.

Lactic Acid Fermentation

A form of fermentation occurring in muscle cells and microorganisms that converts pyruvate into lactic acid when oxygen is limited.

Alcoholic Fermentation

A form of fermentation occurring in yeasts and certain bacteria that converts sugars into alcohol and carbon dioxide.

Homeostasis

The condition of maintaining a stable, balanced internal cellular environment despite external changes, regulated by the cell membrane.

Phospholipids

The primary structural lipid molecules of biological membranes, each possessing a hydrophilic head and hydrophobic fatty acid tails.

Amphipathic

Having both hydrophilic (water-loving) and hydrophobic (water-fearing) regions on the same molecule, characteristic of membrane phospholipids.

Phospholipid Bilayer

The double-layered sheet of oriented phospholipids that forms the fundamental structure and boundary of cell membranes.

Integral Protein

A membrane protein permanently attached to or spanning across the hydrophobic core of the phospholipid bilayer.

Peripheral Protein

A membrane protein temporarily attached to the exterior or interior surface of the phospholipid bilayer.

Glycoprotein

A protein situated in the cell membrane that has a carbohydrate chain covalently attached, functioning in cell-cell recognition and communication.

Glycolipid

A membrane lipid covalently bonded to a carbohydrate chain, contributing to membrane stability and cellular recognition.

Cholesterol

A steroid lipid embedded within the phospholipid bilayer that helps maintain membrane fluidity and stability across temperature variations.

Semipermeable

The characteristic of the cell membrane that selectively permits only certain molecules to pass through while restricting others.

Passive Transport

The movement of substances across a cell membrane down their concentration gradient without requiring cellular energy ($ATP$).

Active Transport

The movement of substances across a cell membrane up or against their concentration gradient, requiring cellular energy in the form of $ATP$.

Concentration

The quantity of solute dissolved in a specific volume of solution or solvent.

Concentration Gradient

The difference in solute concentration between two regions or across a semipermeable membrane that directs the direction of net movement.

Solution

A homogeneous mixture formed by dissolving one or more solutes within a liquid solvent.

Solute

The substance that is dissolved within a solvent to create a solution.

Solvent

The dissolving medium, typically water in biological systems, that dissolves a solute.

Channel Proteins

Transmembrane transport proteins that provide hydrophilic corridors allowing specific ions or polar molecules to diffuse freely down their concentration gradient.

Carrier Proteins

Transport proteins that bind specific molecules and undergo conformational shape changes to move them across the cell membrane.

Protein Pumps

Transmembrane transport proteins that consume energy ($ATP$) to transport ions or molecules across the membrane up their concentration gradient.

Aquaporins

Specialized channel proteins in the plasma membrane that selectively facilitate the rapid passage of water molecules during osmosis.

Simple Diffusion

A type of passive transport where small or nonpolar solutes move directly through the phospholipid bilayer down their concentration gradient without energy.

Facilitated Diffusion

A type of passive transport where molecules move down their concentration gradient across the membrane using channel or carrier proteins without requiring $ATP$.

Osmosis

The diffusion of water across a semipermeable membrane from a region of lower solute concentration to a region of higher solute concentration.

Hypertonic Solution

A solution that has a higher concentration of solute relative to the inside of a cell, causing water to exit the cell.

Hypotonic Solution

A solution that has a lower concentration of solute relative to the inside of a cell, causing water to enter the cell.

Isotonic Solution

A solution that has an equal solute concentration compared to the inside of a cell, resulting in no net movement of water.

Turgid

The swollen and rigid state of a plant cell resulting from high internal hydrostatic pressure when placed in a hypotonic environment.

Plasmolysis

The contraction or shrinking of the plant cell membrane and cytoplasm away from the cell wall caused by water loss in a hypertonic solution.

Flaccid

The limp, non-turgid state of a plant cell resulting from being placed in an isotonic solution where no net osmotic pressure is generated.

Lyse

The bursting or rupture of an animal cell membrane caused by the excessive influx of water in a hypotonic solution.

Bulk Transport

An active transport process that moves large particles or macromolecules across the cell membrane using membrane-bound vesicles.

Endocytosis

An active bulk transport mechanism where the cell engulfs external substances by folding inward its plasma membrane to form vesicles.

Exocytosis

An active bulk transport mechanism where intracellular vesicles fuse with the plasma membrane to secrete or release their contents outside the cell.

Phagocytosis

A form of endocytosis known as cellular eating, where large solid particles, foreign debris, or whole cells are engulfed by the cell.

Pinocytosis

A form of endocytosis known as cellular drinking, where extracellular fluids containing dissolved solutes are engulfed in tiny vesicles.

Receptor-Mediated Endocytosis

A highly targeted type of endocytosis where specific extracellular molecules bind to receptor proteins on the membrane surface before vesicle formation.