Cell Structure and Function Review Flashcards

A complete set of 87 vocabulary flashcards covering cell structure, function, transport mechanisms, organelles, and cell division based on the lecture transcript.

Cell

The most basic living functional unit in the human body.

Cell Type Diversity

There are over $200$ different types of cells in the human body.

Cellular Variation

Cells vary in size and shape, but they share common structures and functions.

Plasma Membrane

Defines the cell boundary and controls the movement of substances in and out of the cell.

Cytoplasm

Jelly-like substance where cellular components are located and the site for many metabolic reactions.

Nucleus

Contains genetic material (DNA) and controls cell activities including growth and reproduction.

Cytosol

The intracellular fluid portion of the cytoplasm in which organelles are located.

Organelles

The 'little organs' located within the cytoplasm of a cell.

Plasma Membrane Barrier Function

Separates the cell from its external environment.

Plasma Membrane Transport Function

Regulates the entry and exit of substances across the cell.

Plasma Membrane Communication Function

Contains receptors that allow the cell to receive signals from the environment.

Fluid Mosaic Model

A model describing the plasma membrane structure composed mainly of a phospholipid bilayer with cholesterol, glycolipids, and proteins.

Plasma Membrane Composition

Composed mainly of a phospholipid bilayer containing phospholipids, cholesterol, glycolipids, and proteins that determine membrane-specific functions.

Major Role of Membrane Lipid Portion

To create a semi-permeable barrier that regulates the movement of substances.

Hydrophilic Head

The polar part of a phospholipid that faces the watery environment both inside and outside the cell.

Hydrophobic Tails

The two nonpolar parts of a phospholipid positioned in the interior of the bilayer, shielded from water.

Interstitial Fluid

The fluid found in the spaces between cells, providing nutrients and a medium for waste exchange.

Glycolipids

Lipids with carbohydrate groups located exclusively on the outer surface of the plasma membrane.

Glycocalyx

A sugary coating composed of glycoproteins and glycolipids on the extracellular surface of the plasma membrane.

Functions of Glycocalyx

Protects the cell, facilitates cell recognition, and aids in communication between cells.

Tight Junctions

Membrane junctions that prevent substances from passing between cells, creating a barrier.

Desmosomes

Membrane junctions that anchor adjacent cells together, providing resistance to mechanical stress.

Gap Junctions

Membrane junctions that allow direct cell communication through channels enabling the passage of ions and small molecules.

Integral Protein

A membrane protein that penetrates the bilayer and is involved in transport or acts as a receptor.

Peripheral Protein

A membrane protein loosely attached to the membrane surface involved in signaling and cell shape.

Receptor

A type of membrane protein that binds to specific signaling molecules (ligands) and triggers a response within the cell.

Ligand

A molecule that binds specifically to another molecule, typically a receptor, to initiate a biological response.

Selective Permeability

The property of an intact biological membrane to allow some substances to pass while preventing others.

Passage of Nonpolar Substances

Nonpolar substances such as lipids or gases (like oxygen and carbon dioxide) can pass through the lipid portion of the plasma membrane readily.

Channel Protein

A transport protein that acts as an escort allowing small polar molecules like water to pass across the plasma membrane.

Gradient

A difference in concentration or energy between two areas.

Concentration Gradient

The gradual change in the concentration of solutes in a solution as a function of distance across a space.

Temperature Gradient

A difference in temperature between two distinct areas.

Passive Transport

Movement of substances across the membrane down their concentration gradient without the use of cellular energy (ATP).

Active Transport

Movement of substances across the membrane up their concentration gradient, requiring cellular energy (ATP).

Simple Diffusion

Movement of small nonpolar molecules through the phospholipid bilayer without protein assistance.

Facilitated Diffusion

Movement of polar molecules or ions through a protein channel or carrier protein in the membrane.

Osmolarity

The measure of solute concentration in a solution, specifically the total number of solute particles per liter of solution ($\text{osmoles/L}$).

Osmosis

The movement of water molecules through a selectively permeable membrane from an area of lower solute concentration to an area of higher solute concentration.

Tonicity

The ability of a solution to affect the size (volume) of cells by changing their water content through osmosis.

Isotonic Solution

A solution in which the solute concentration is equal inside and outside of the cell, resulting in no net movement of water.

Hypertonic Solution

A solution with a higher solute concentration compared to the cell, causing the cell to lose water and shrink.

Hypotonic Solution

A solution with a lower solute concentration compared to the cell, causing the cell to absorb water, swell, and potentially burst.

Crenation

The shrinkage of a red blood cell when placed in a hypertonic solution.

Hemolysis

The swelling and bursting of a red blood cell when placed in a hypotonic solution.

Primary Active Transport

A process that uses a transport protein ('pump') to move solute against its concentration gradient using energy.

Sodium-Potassium Pump

An active transport system that moves $Na^+$ out of the cell and $K^+$ into the cell to establish and maintain electrochemical gradients.

Vesicular Transport

The transport of substances into the cell by endocytosis or out of the cell by exocytosis using vesicles.

Phagocytosis

A type of endocytosis involving the engulfing of large particles or cells ('cell eating').

Pinocytosis

A type of endocytosis involving the engulfing of small particles or liquids ('cell drinking').

Receptor-Mediated Endocytosis

Specific cellular uptake of molecules after binding to extracellular receptors.

Exocytosis

The cellular process of transporting substances out of the cell via vesicles, essential for secretion and cell communication.

Cellular Ion Distribution

Inside the cell has higher concentrations of $K^+$; outside the cell has higher concentrations of $Na^+$ and $Cl^-$.

Intracellular Protein Concentration

The concentration of proteins is higher inside the cell compared to outside the cell.

Resting Membrane Potential

The electrical potential difference across the plasma membrane of a resting neuron or muscle cell, defaulted at $-70\,mV$.

Maintenance of Resting Membrane Potential

Generated and maintained by the sodium-potassium pump ($Na^+$ out, $K^+$ in) and differential membrane permeability.

Cell Activation Mechanism

Changes in the resting membrane potential activate neurons and muscle cells.

Cell Communication Methods

Direct contact (e.g., cell adhesion molecules) or ligand-receptor signaling (e.g., hormones) leading to cellular responses.

Rough Endoplasmic Reticulum

A membrane-bound organelle that synthesizes and modifies proteins for export or use in the cell membrane.

Smooth Endoplasmic Reticulum

A membrane-bound organelle that synthesizes lipids, metabolizes carbohydrates, and detoxifies drugs and poisons.

Golgi Apparatus

A membrane-bound organelle that modifies, sorts, and packages proteins and lipids for export or internal cell use.

Lysosomes

Membrane-bound organelles containing digestive enzymes to break down waste materials and cellular debris.

Peroxisomes

Membrane-bound organelles that break down fatty acids and detoxify harmful substances.

Mitochondria

Membrane-bound organelles that produce ATP through cellular respiration, known as the powerhouse of the cell.

Ribosome

A non-membrane-bound organelle that synthesizes proteins by translating messenger RNA (mRNA) into polypeptide chains.

Cytoskeleton

A network of protein filaments and tubules that maintains cell shape, positions organelles, enables intracellular transport, and aids cell movement.

Microfilaments

Cytoskeletal filaments composed of actin that provide structural support and enable cell movement, such as in muscle contraction.

Intermediate Filaments

Cytoskeletal filaments that provide mechanical support and stabilize cell structures.

Microtubules

Cytoskeletal filaments composed of tubulin that maintain cell shape, facilitate cell division, and aid intracellular transport.

Centrosome with Centrioles

The main microtubule-organizing center of the cell that organizes the mitotic spindle during cell division.

Cellular Extensions

Structures extending from the surface of some cells, including cilia, flagella, and microvilli.

Cilia

Hair-like structures that help move substances along the cell surface, such as clearing mucus in the respiratory tract.

Flagella

Whip-like structures that enable cell movement, such as on sperm cells allowing them to swim.

Nucleolus

A structure in the nucleus responsible for synthesizing ribosomal RNA (rRNA) and assembling ribosome subunits.

Chromatin

The complex of DNA and proteins (histones) making up chromosomes in a less condensed form during interphase.

Chromosome

A tightly coiled structure composed of DNA and proteins containing genetic information, visible during cell division.

Gene

A segment of DNA that encodes instructions for synthesizing a specific protein or function, serving as the basic unit of heredity.

Steps of Protein Synthesis

The two major steps of protein synthesis are transcription and translation.

Transcription

The process where the DNA sequence of a gene is copied into messenger RNA (mRNA) by RNA polymerase.

Translation

The process where mRNA is read by ribosomes to synthesize a polypeptide chain (protein) with tRNA bringing specific amino acids.

Organelle Involved in Translation

The ribosome is the organelle directly involved in translation.

Interphase

The stage where the cell grows, duplicates DNA, and prepares for division, consisting of G1, S, and G2 phases.

Mitosis

The process where replicated chromosomes separate into two daughter cells across prophase, metaphase, anaphase, and telophase.

Cytokinesis

The division of the cytoplasm resulting in two separate daughter cells, each with organelles and a nucleus.

Somatic Cell

Any biological body cell except reproductive cells (gametes), containing $46$ chromosomes ($23$ pairs) in humans.

Somatic Cell Division

Division via mitosis resulting in two genetically identical daughter cells with $46$ chromosomes.

Reproductive Cell

A gamete (sperm or egg cell) containing $23$ chromosomes (haploid), produced via meiosis to ensure fertilization restores $46$ chromosomes.