Cell Biology and Membrane Transport

Flashcards covering key vocabulary terms related to cell structure, organelles, and membrane transport mechanisms as discussed in the lecture.

Genetic Makeup

Controls cellular regeneration and makes identical copies of mother cells.

Mitosis

The process of cellular division, resulting in identical copies of the mother cell.

Nucleus

The organelle that powers the cell and contains its genetic information.

Cell Membrane

Maintains cellular boundaries and is selectively permeable.

Cytoplasm

The fluid components located within a cell.

Red Blood Cells

Unique cells that eject their nucleus two days after entering circulation, losing their ability to regenerate themselves.

Erythropoietin

A hormone released by the kidneys that signals bone marrow to produce more red blood cells, typically in response to a decline in oxygen.

Nuclear Envelope

The membrane surrounding the nucleus, containing pores for transport of substances.

Chromatin and Nucleolus

Components within the nucleus primarily involved with DNA.

Smooth Endoplasmic Reticulum (SER)

Involved in storage and lipid synthesis.

Mitochondria

Known as the "powerhouse of the cell" due to its production of ATP.

Lysosome

An organelle responsible for killing foreign substances and cellular waste, often referred to as "Lysol of the cell."

Centrosome and Centrioles

Organize the cell, particularly in preparation for cellular division by aligning structures before mitotic spindle formation.

Microtubules

Cytoskeletal elements that maintain the cell's shape.

Intermediate Filaments

Cytoskeletal elements that contribute to the cell's structure and form connections in desmosomes.

Peroxisomes

Organelles that detoxify free radicals and prevent toxins from invading the cell.

Vesicle

A small sac within a cell that contains and transports substances, acting as a "suitcase."

Vesicular Trafficking

The process of moving vesicles within the cell, which requires ATP and is a form of active transport.

Golgi Apparatus

Functions as the "UPS station" of the cell, editing and directing proteins to their various destinations.

Rough Endoplasmic Reticulum (RER) and Ribosomes

Key organelles involved in protein synthesis.

Selectively Permeable

A characteristic of the plasma membrane, meaning it is "picky" about what substances can pass through.

Hydrophilic Heads

The polar, water-attracting parts of the phospholipid bilayer that face the watery environments (blood and cytoplasm).

Hydrophobic Tails

The nonpolar, water-fearing parts of the phospholipid bilayer that reside within the membrane, preventing water passage.

Aquaporin

A specific protein channel that allows water to pass through the selectively permeable plasma membrane.

Lipids (small)

Can pass directly through the plasma membrane because the membrane itself is composed of phospholipids, allowing lipids to dissolve through.

Integral Proteins

Proteins embedded within the plasma membrane that form channels for larger molecules and ions.

Peripheral Proteins

Proteins located on the surface of the plasma membrane, important for cell signaling and containing receptors.

Receptors

Specific binding sites on cells (often on peripheral proteins) that allow for cell-to-cell communication and signal specific hormones or messengers.

Glycocalyx

A "sugar coat" made of carbohydrate chains on the outside of cells, crucial for cell-to-cell recognition.

Cholesterol (in Plasma Membrane)

Provides stability to the plasma membrane, allowing cells to maintain their shape and recover from compression.

Active Transport

A form of membrane transport that requires cellular energy (ATP) to move substances, often against their concentration gradient.

Passive Transport

A form of membrane transport that does not require cellular energy (ATP), moving substances down their concentration gradient.

Enzymes

Proteins that act as biological catalysts, speeding up chemical reactions by lowering activation energy without being consumed in the process.

Cell Adhesion Molecules (CAMs)

Binding sites that facilitate cell-to-cell communication and connections, particularly in nerve impulses and bone remodeling.

Tight Junctions

Specialized cell junctions where cells are tightly bound together, forming a barrier to prevent substances (e.g., bacteria) from invading underlying tissues (found in mouth, esophagus, bladder).

Desmosomes

Anchoring junctions that connect cells via intermediate filaments, providing strong adhesion and resistance to mechanical stress (e.g., in the skin).

Gap Junctions

Communicating junctions that form small channels (conexons) between cells, allowing for the passage of ions and signals (e.g., in cardiac muscle, ovaries, bones).

Simple Diffusion

The movement of particles from an area of high concentration to an area of low concentration, not requiring cellular energy or always a channel.

Rate of Diffusion Influencers

Factors including molecular size (smaller is faster), temperature (higher is faster), membrane permeability, and concentration difference.

Facilitated Diffusion

A type of passive transport where molecules move across the membrane with the help of a protein channel or carrier, but without cellular energy expenditure.

Osmosis

The movement of water across a selectively permeable membrane from an area of high water concentration to an area of low water concentration, not requiring cellular energy.

Equilibrium

The goal state for cells where there is a stable environment, often achieved through balancing concentrations.

Isotonic Solution

A solution with the same solute concentration as the cell's cytoplasm, resulting in no net water movement.

Hypertonic Solution

A solution with a higher solute concentration than the cell's cytoplasm, causing water to leave the cell and leading to crenation.

Hypotonic Solution

A solution with a lower solute concentration than the cell's cytoplasm, causing water to enter the cell and potentially leading to lysis.

Crenation

The process where a cell shrinks and shrivels due to water loss when placed in a hypertonic solution.

Lysis (Cell Lysis)

The process where a cell swells and bursts due to excessive water intake when placed in a hypotonic solution.

Hydrolysis

A chemical reaction where water is added to split a larger molecule into smaller ones.

Primary Active Transport

Directly uses ATP to pump specific ions or molecules across the membrane against their concentration gradient, exemplified by the sodium-potassium pump.

Secondary Active Transport

Indirectly uses the energy stored in an ion gradient (established by primary active transport) to move another molecule against its concentration gradient (e.g., glucose, amino acids).

Endocytosis

The process by which cells take in substances from their external environment by engulfing them in a vesicle, requiring ATP.

Phagocytosis

A specific type of endocytosis where the cell "eats" large particles by engulfing them.

Pinocytosis

A specific type of endocytosis where the cell "drinks" by taking in samples of extracellular fluid.

Exocytosis

The process by which cells release substances to the exterior by fusing a vesicle with the plasma membrane, requiring ATP.

Resting Membrane Potential

The electrical potential difference across the plasma membrane of a cell at rest, maintained by ion gradients and pumps.