General Biology (LIFE 1010) - Unit 2 Concept Flashcards

Vocabulary flashcards covering Unit 2 topics of General Biology (LIFE 1010): Cell Structure, Energy & Metabolism, Cellular Respiration, and Photosynthesis.

Cell Theory

The fundamental biological principle stating that all living organisms are composed of one or more cells, the cell is the basic structural and functional unit of life, and all cells arise from pre-existing cells.

Prokaryote

A unicellular organism that lacks a membrane-bound nucleus and membrane-bound organelles.

Eukaryote

An organism whose cells contain a membrane-bound nucleus and other specialized membrane-enclosed organelles.

Nucleus

The membrane-bound eukaryotic organelle that houses the cell's genetic material (DNA) and directs cellular activities.

Ribosome

A cellular structure composed of RNA and protein that synthesizes proteins by translating mRNA.

Rough Endoplasmic Reticulum (Rough ER)

A region of the endoplasmic reticulum studded with ribosomes that participates in protein synthesis, modification, and transport.

Smooth Endoplasmic Reticulum (Smooth ER)

A region of the endoplasmic reticulum devoid of ribosomes that functions in lipid synthesis, carbohydrate metabolism, and detoxification.

Golgi Apparatus

A eukaryotic organelle composed of flattened membranous sacs that modifies, sorts, and packages proteins and lipids for secretion or delivery to other organelles.

Lysosome

A membrane-enclosed sac of hydrolytic enzymes found in animal cells used to digest macromolecules and recycle cellular components.

Vacuole

A membrane-bound organelle that functions in cellular storage, waste disposal, and maintaining turgor pressure in plant cells.

Mitochondrion

A double-membrane organelle that serves as the site of cellular respiration and produces most of the cell's ATP.

Chloroplast

A photosynthetic organelle found in plants and algae that captures light energy to produce organic molecules from carbon dioxide and water.

Cytoskeleton

A network of protein filaments and tubules extending throughout the cytoplasm that provides structural support, facilitates movement, and anchors organelles.

Cell Wall

A rigid outer layer surrounding the plasma membrane of plant, fungi, and prokaryotic cells that provides structural protection and shape.

Endosymbiosis Theory

The evolutionary theory proposing that mitochondria and chloroplasts originated as free-living prokaryotic cells that were engulfed by ancestral eukaryotic host cells.

First Law of Thermodynamics

The physical law of energy conservation stating that energy cannot be created or destroyed, only transformed from one form to another.

Second Law of Thermodynamics

The physical principle stating that every spontaneous energy transfer or transformation increases the total entropy (disorder) of the universe.

Entropy

A quantitative measure of randomness or disorder in a system.

Redox Reaction

A chemical reaction involving the transfer of electrons from one reactant to another, coupling oxidation (loss of electrons) with reduction (gain of electrons).

Gibbs Free Energy ($\Delta G$)

The portion of a system's energy that can perform work under constant temperature and pressure; a negative $\Delta G$ indicates a spontaneous process.

Exergonic Reaction

A spontaneous chemical reaction that releases free energy, characterized by a negative change in free energy ($\Delta G < 0$).

Endergonic Reaction

A non-spontaneous chemical reaction that absorbs free energy from its surroundings, characterized by a positive change in free energy ($\Delta G > 0$).

Activation Energy

The minimum amount of energy required to initiate a chemical reaction by reaching the transition state.

Competitive Inhibition

A mode of enzyme regulation where an inhibitor directly binds to the active site, preventing the substrate from entering.

Allosteric Regulation

A mechanism in which a regulatory molecule binds to a site other than the active site (allosteric site), inducing a conformational change that either activates or inhibits enzyme function.

Catabolic Reaction

A metabolic pathway that breaks down complex molecules into simpler compounds, releasing energy.

Anabolic Reaction

A metabolic pathway that synthesizes complex molecules from simpler ones, requiring an input of energy.

Autotroph

An organism that produces its own organic food molecules from inorganic raw materials using light or chemical energy.

Heterotroph

An organism that obtains organic molecules and energy by consuming other organisms or organic substances.

Glycolysis

The cytoplasmic metabolic pathway that splits glucose into two molecules of pyruvate, producing a net gain of $2\,\text{ATP}$ and $2\,\text{NADH}$.

Pyruvate Processing

The conversion of pyruvate into acetyl-CoA in the mitochondrial matrix, producing $\text{CO}_2$ and $\text{NADH}$.

Citric Acid Cycle

A metabolic pathway occurring in the mitochondrial matrix that oxidizes acetyl-CoA to $\text{CO}_2$, generating $\text{ATP}$, $\text{NADH}$, and $\text{FADH}_2$.

Chemiosmosis

An energy-coupling mechanism that uses an electrochemical proton ($\text{H}^+$) gradient across a membrane to drive cellular work, specifically ATP synthesis.

ATP Synthase

A membrane-embedded protein complex that utilizes the proton-motive force across a membrane to phosphorylate ADP into ATP.

Fermentation

An anaerobic catabolic process that regenerates $\text{NAD}^+$ from $\text{NADH}$ via glycolysis without the use of an electron transport chain.

Photosystem II (PS2)

A light-harvesting complex in the thylakoid membrane that splits water, releases oxygen, and transfers excited electrons through an ETC to generate ATP via chemiosmosis.

Photosystem I (PS1)

A light-harvesting complex in the thylakoid membrane that absorbs light energy to re-excite electrons and transfer them to reduce $\text{NADP}^+$ into $\text{NADPH}$.

Calvin Cycle

The light-independent stage of photosynthesis occurring in the stroma that utilizes $\text{CO}_2$, ATP, and NADPH to synthesize carbohydrates.

Rubisco

The enzyme (ribulose-1,5-bisphosphate carboxylase-oxygenase) that catalyzes the carbon fixation step of the Calvin cycle, joining $\text{CO}_2$ to RuBP.