Biology unit 1.1

Comprehensive vocabulary flashcards covering enzymes, cellular transport mechanisms (diffusion, osmosis, active transport), cellular respiration (aerobic and anaerobic), the mechanics and pathology of the respiratory system, and plant cell structure.

Enzyme

A biological catalyst made of protein that speeds up the rate of chemical reactions in cells without being used up.

Active Site

The specific region of an enzyme with a unique shape where a complementary substrate molecule binds to undergo a chemical reaction.

Substrate

The specific molecule that collides with and fits into the active site of an enzyme to be broken down or built up into products.

Enzyme-Substrate Complex

The temporary complex formed when a substrate molecule collides with and successfully fits into the complementary active site of an enzyme, analogous to a key fitting into a lock.

Optimum Temperature

The temperature at which an enzyme exhibits the maximum rate of reaction due to the highest number of successful collisions per unit time between enzymes and substrates.

Denaturation

The irreversible destruction of an enzyme's specific active site shape, caused by high temperatures or extreme pH, which prevents the substrate from binding and halts the reaction.

Triplet Code (DNA)

A sequence of $3$ DNA bases within a gene that codes for one specific amino acid in a protein chain.

Amino Acids

The small monomer molecules linked in chains that fold into a unique 3D shape to form proteins and functional enzymes.

Inspired Air

The air breathed into the lungs, consisting of approximately $21\%$ oxygen, $0.04\%$ carbon dioxide, $78\%$ nitrogen, and a variable proportion of water vapor.

Expired Air

The air breathed out of the lungs, consisting of approximately $16\%$ oxygen, $4\%$ carbon dioxide, $78\%$ nitrogen, and saturated with water vapor.

Tar

A toxic, sticky chemical component found in cigarette smoke that contains carcinogens that cause lung cancer.

Nicotine

The addictive chemical component found in cigarette smoke that causes dependency.

Emphysema

A respiratory disease caused by smoking in which the alveolar walls break down, significantly reducing the surface area for gas exchange and leaving patients struggling to obtain enough oxygen.

Goblet Cells

Specialized cells in the lining of the airways that produce mucus to trap inhaled dust particles and bacteria.

Ciliated Epithelial Cells

Cells lining the airways possessing tiny hair-like projections (cilia) that beat in a coordinated rhythm to move mucus up the trachea to be swallowed.

Limewater Test

A qualitative chemical test for carbon dioxide gas; the solution turns from clear to cloudy or milky when carbon dioxide is bubbled through it.

Diffusion

The passive net movement of continuously moving liquid or gas molecules from an area of higher concentration to an area of lower concentration down a concentration gradient.

Osmosis

The diffusion of water molecules from an area of high water concentration (dilute solute solution) to an area of low water concentration (concentrated solute solution) across a selectively permeable membrane.

Selectively Permeable Membrane

A membrane containing microscopic pores that allows small molecules (such as water) to pass through freely while blocking larger solute molecules (such as sugar or salt).

Visking Tubing

An artificial, selectively permeable tubing with microscopic pores used in laboratory experiments to model the behavior of cell membranes.

Active Transport

The active process that moves molecules across a cell membrane against a concentration gradient, requiring metabolic energy in the form of $\text{ATP}$ provided by cellular respiration.

Turgid

The firm, swollen state of a plant cell that occurs when water enters by osmosis, causing the vacuole to expand and push the cytoplasm firmly against the cellulose cell wall.

Flaccid

The limp, soft state of a plant cell resulting from the net loss of water by osmosis, causing the vacuole to shrink and the plant tissue to wilt.

Aerobic Respiration

A series of enzyme-controlled chemical reactions occurring in the mitochondria of cells where glucose reacts with oxygen to release carbon dioxide, water, and energy stored as $\text{ATP}$ and heat.

Anaerobic Respiration

A shorter series of enzyme-controlled reactions occurring in the absence of oxygen that partially breaks down glucose into toxic lactic acid, releasing less energy ($\text{ATP}$) than aerobic respiration.

Oxygen Debt

The volume of additional oxygen required after strenuous exercise to break down and eliminate the toxic lactic acid produced during anaerobic respiration.

Inspiration

The active process of inhaling in which intercostal muscles contract lifting ribs up and out, the diaphragm contracts and flattens, increasing thorax volume and decreasing internal pressure below atmospheric pressure to draw air into the lungs.

Expiration

The process of exhaling in which intercostal muscles relax (ribs move down and in) and the diaphragm relaxes and domes up, decreasing thorax volume and increasing pressure to force air out of the lungs.

Alveoli

Microscopic air sacs in the lungs adapted for efficient gas exchange by having an extensive surface area, thin walls, a moist lining, and an abundant blood capillary network.

Mitochondria

Membrane-bound cellular organelles where aerobic respiration takes place to release energy from glucose for life processes such as movement and growth; abundant in liver and muscle cells.

Cell Sap

The watery solution of dissolved sugars and salts contained within the permanent vacuole of a plant cell.

Cellulose Cell Wall

The strong, rigid outer layer surrounding plant cell membranes that provides structural support and prevents cells from bursting when water enters.