BIO101 Exam 2 Review - Principles of Biology

Vocabulary practice flashcards covering membrane transport, enzymes, cellular respiration, and photosynthesis for BIO101 Exam 2 Review.

Fluid-Mosaic Model

The model that best describes the structure and dynamic nature of the cell (plasma) membrane.

Membrane Fluidity

The degree of viscous movement within a cell membrane, maximized by combinations such as cholesterol and unsaturated lipids.

Selective Permeability

A characteristic of cell membranes with hydrophobic interiors that regulates the passage of substances into and out of the cell.

Facilitated Diffusion

Passive transport of charged or polar substances, such as sodium ions ($Na^+$), across a membrane via transport proteins.

Passive Diffusion

The direct movement of small, nonpolar molecules, such as oxygen gas ($O_2$), across the phospholipid bilayer.

Active Transport

An energy-requiring transport process that moves ions or molecules, such as potassium ions ($K^+$), across a membrane.

Hypotonic Solution

An external solution preferred by plant cells that causes a net inward movement of water when human red blood cells are exposed to it.

Hypertonic Solution

A solution of higher solute concentration that causes human red blood cells to lose water, appearing shrunken and shriveled.

Endergonic Reactions

Chemical reactions in which the reactants possess less energy than the products.

Enzymes

Biological catalysts whose role is to speed up reactions by lowering activation energies.

Substrate

The specific reactant molecule upon which an enzyme acts, such as sucrose when degraded by sucrase.

Competitive Inhibitors

Inhibitor molecules that physically block substrates from binding to an enzyme's active site.

Noncompetitive Inhibitors

Inhibitor molecules that bind to a site on the enzyme other than the active site.

Reactants of Cellular Respiration

The chemical inputs required for cellular respiration, specifically glucose and oxygen ($O_2$).

Steps of Cellular Respiration

The four sequential stages: glycolysis, pyruvate oxidation, citric acid cycle, and oxidative phosphorylation.

Cytosol

The fluid portion of the cytoplasm where glycolysis occurs, representing the only step of cellular respiration outside the mitochondria.

Glycolysis

The initial metabolic pathway common to both aerobic and anaerobic cellular respiration that splits glucose.

Products of Pyruvate Oxidation

Two acetyl CoA molecules generated per glucose before entry into the citric acid cycle.

Citric Acid Cycle

The stage of cellular respiration whose purpose is to generate energy carriers in the form of NADH and $FADH_2$ using acetyl CoA.

Oxidative Phosphorylation

The final stage of cellular respiration, consisting of the electron transport chain and chemiosmosis.

Electron Transport Chain

A series of protein complexes that release energy stored in moving electrons to provide energy for $H^+$ movement across a membrane.

ATP Synthase

An enzyme driven by an $H^+$ concentration gradient to synthesize ATP molecules.

Reduction

The biologically accurate process defined as the addition of electrons to a molecule, such as oxygen gaining electrons to form water.

Lipids (Cellular Respiration)

The biomolecules that yield the greatest amount of energy when broken down during cellular respiration (e.g., during fasting).

Reactants of Photosynthesis

The inputs required for photosynthesis: carbon dioxide ($CO_2$), water ($H_2O$), and sunlight.

Chlorophylls

The primary pigment molecules within plant cells that absorb light to conduct photosynthesis.

Steps of Photosynthesis

The sequential phases of photosynthesis: light-dependent reactions followed by light-independent reactions.

Light-Dependent Reactions

The initial reactions of photosynthesis utilizing an electron transport chain to synthesize ATP molecules that fuel glucose synthesis.

Light-Independent Reactions

The Calvin cycle reactions taking place in the stroma with the main purpose of synthesizing glucose as a source of energy.

NADPH

The primary electron carrier molecule produced and used in photosynthesis.

Stroma

The fluid interior of the chloroplast where the light-independent reactions (Calvin cycle) take place.

Photorespiration

The process where oxygen gas ($O_2$) is used during the Calvin cycle rather than carbon dioxide ($CO_2$).

Calvin Cycle

A cyclical metabolic pathway that requires 6 turns to synthesize 1 full glucose molecule from carbon dioxide.

$C_3$ Plants

A classification of plants that thrive in cool climates.

$CAM$ Plants

A plant type adapted to arid climates that only opens its stomata at night.

Order of Metabolism in Plant Cells

The overall sequence of energetic pathways in plants: photosynthesis followed by cellular respiration.