The Cell Lecture Fundamentals

Flashcards covering basic cell processes, components, transport mechanisms, organelle functions, and the stages of the cell cycle based on the lecture transcript.

Cell metabolism

The sum of all chemical reactions that a cell carries out to maintain life.

Cell reproduction

A process necessary for growth, development, and the replacement of old or damaged cells.

Plasma membrane

A structure that provides support, regulates transport, and defines the intracellular space from the extracellular space.

Cytosol

The intracellular fluid (ICF) contained within the cytoplasm.

Organelles

A variety of cellular structures with very specific functions vital to maintaining homeostasis.

Nucleus

The governing body of the cell that contains most of the DNA and is the primary location for making RNA.

Phospholipid bilayer

A water-resistant barrier consisting of hydrophilic phosphate heads and hydrophobic fatty acid tails.

Fluid Mosaic Model

The current model describing the plasma membrane as a constantly changing mosaic of proteins, lipids, and carbohydrates.

Ligand

A specific molecule that binds to a membrane receptor to trigger a change in the protein or the cell.

Cholesterol

A lipid molecule that stabilizes the plasma membrane's fluid structure during temperature changes.

Agonists

Drugs that mimic a ligand's actions by stimulating a receptor.

Antagonists

Drugs that inhibit a ligand's actions by blocking a receptor.

Diffusion

The movement of solute molecules from an area of higher concentration to an area of lower concentration.

Facilitated diffusion

The movement of charged or polar solutes, such as ions or glucose, across the bilayer with the help of a carrier or channel.

Osmosis

The movement of solvent (usually $H_2O$) across a membrane from a solution with lower solute concentration to one with higher solute concentration.

Aquaporins

Water channels that allow water to cross the plasma membrane.

Isotonic

A condition where the extracellular fluid has the same osmotic pressure as the cytosol.

Hypertonic

An ECF with a higher solute concentration than the cytosol, causing the cell to shrink or crenate.

Hypotonic

An ECF with a lower solute concentration than the cytosol, causing the cell to swell or lyse.

Active transport

Processes requiring energy in the form of ATP to move solutes against their concentration gradients via carrier proteins called pumps.

Phagocytosis

Known as 'cell eating,' it is the process where cells ingest large particles like bacteria or dead cells.

Pinocytosis

Known as 'cell drinking,' it is the process where cells engulf fluid droplets from the ECF.

Exocytosis

The process by which large molecules exit the cell, also known as secretion.

Mitochondria

The 'power plant' of the cell involved in chemical energy production and producing the majority of the cell's ATP.

Peroxisomes

Organelles that use oxygen to produce $H_2O_2$ and oxidize toxic chemicals to less toxic compounds.

Ribosomes

The sites within the cell where protein synthesis takes place.

Rough endoplasmic reticulum (RER)

A folded phospholipid bilayer with bound ribosomes that packages secretory proteins and produces membrane components.

Smooth endoplasmic reticulum (SER)

An organelle lacking ribosomes that is involved in lipid synthesis, detoxification reactions, and calcium ion storage.

Cystic fibrosis

A disease caused by a misfolded chloride ion channel protein in the RER, leading to abnormally thick mucus.

Golgi apparatus

Flattened membranous sacs that modify, sort, and package proteins and lipids for export.

Lysosomes

Organelles containing acid hydrolases responsible for digesting worn-out cell components and invading bacteria.

Tay-Sachs disease

A lysosomal disease where glycolipids accumulate in brain lysosomes, leading to progressive neural dysfunction.

Microvilli

Finger-like extensions of the plasma membrane that increase surface area for absorption.

Cilia

Hair-like projections that sweep substances past the cell, found in the respiratory and female reproductive tracts.

Flagella

Single, long extensions that propel the entire cell through liquid, found only on sperm cells in humans.

Chromatin

A loose structural arrangement in a non-dividing cell consisting of one long DNA molecule and histone proteins.

Transcription

The process where DNA is copied to create messenger RNA (mRNA).

Translation

The process where mRNA binds with a ribosome to initiate the synthesis of a protein.

Mutagens

Agents such as ultraviolet light, radiation, or chemicals like benzene that induce changes in DNA.

Interphase

The period of growth and preparation for cell division, consisting of G1, S, and G2 phases.

Mitosis

The division of newly replicated genetic material between two daughter cells, occurring in four stages: prophase, metaphase, anaphase, and telophase.

Apoptosis

A process of programmed cell death for cells that cannot pass checkpoints or be repaired.

Metastasis

The process where malignant tumor cells spread to other locations in the body.

Diploid

A cell that has a full paired set of chromosomes ($2n$); in humans, this is 46 chromosomes.

Haploid

A cell produced by meiosis that has only half the number of chromosomes ($1n$) of the original cell.