Comprehensive Biology Exam Study Guide: Macromolecules, Cells, Transport, Mitosis & Homeostasis

Vocabulary flashcards generated directly from the 150-question exam study guide, detailing key terms across macromolecules, enzyme kinetics, cell organelles, cell transport mechanisms, mitosis, and body fluid/acid-base homeostasis.

CHNOPS

An acronym representing the six major chemical elements that compose living organisms: carbon, hydrogen, oxygen, nitrogen, phosphorus, and sulfur.

Organic Compounds

Chemical compounds that contain significant amounts of carbon, in contrast to inorganic compounds which generally do not contain carbon.

Macromolecule

A very large organic molecule; many macromolecules are constructed as polymers.

Polymer

A large molecule composed of repeating smaller structural units termed monomers.

Monomer

A small building-block molecule that can covalently bind with other monomers to form a polymer.

Dehydration Synthesis

A condensation reaction in which a water molecule is removed/released as monomers are joined together.

Hydrolysis

A chemical reaction in which a water molecule is added to break the bonds between monomers.

Carbohydrates

Organic molecules used primarily as a quick or short-term energy source; classified into monosaccharides, disaccharides, and polysaccharides.

Monosaccharide

A simple sugar consisting of a single sugar unit, such as glucose or fructose.

Disaccharide

A sugar consisting of two linked monosaccharide units, such as sucrose.

Polysaccharide

A complex carbohydrate composed of many linked sugar units, such as starch or glycogen.

Lipids

Water-insoluble organic molecules that store large amounts of energy, constitute cell membranes, act as chemical messengers (hormones), protect, and insulate.

Saturated Fatty Acids

Fatty acids that possess no carbon-carbon double bonds.

Unsaturated Fatty Acids

Fatty acids that contain one or more carbon-carbon double bonds.

Proteins

Polymers of amino acids that carry out functions including storage (albumin), transport (hemoglobin), regulation, movement, structure, and enzyme activity; organized into primary, secondary, tertiary, and quaternary structures.

Nucleic Acids

Molecules such as double-stranded DNA and generally single-stranded RNA that carry genetic information and instructions to make proteins.

Nucleotide

The structural subunit of nucleic acids, consisting of a phosphate group, a 5-carbon sugar, and a nitrogenous base.

Catalyst

A substance that speeds up a chemical reaction rate without being consumed by the reaction.

Enzyme

An organic biological catalyst, typically a protein, that lowers activation energy to speed up chemical reactions.

Substrate

The specific molecule upon which an enzyme acts.

Active Site

The region on an enzyme where the substrate binds.

Induced Fit

The operational model where an enzyme is flexible and alters its shape slightly as the substrate binds while maintaining specificity.

Coenzyme

An organic enzyme helper, often derived from a vitamin.

Cofactor

An inorganic enzyme helper, often a metal ion such as iron.

Denaturation

A change in an enzyme's shape caused by extreme pH or temperature, altering the active site so the substrate no longer fits.

Generalized Cell Model

A theoretical representation of a cell incorporating many typical structures, although no single cell possesses every structure.

Nucleus

The cellular organelle that contains DNA and directs the cell's activities.

Cytoplasm

The material situated between the nucleus and cell membrane, consisting of cytosol, organelles, membranes, and the cytoskeleton.

Cytosol

The clear fluid portion of the cytoplasm in which organelles are suspended.

Cell Membrane

A selectively permeable boundary consisting of lipids, proteins, and carbohydrates that encloses the cell and regulates entry and exit.

Phospholipid Bilayer

A double layer of phospholipids with hydrophilic heads facing watery environments and hydrophobic fatty-acid tails facing inward.

Cholesterol (Membrane)

A lipid in the cell membrane that stabilizes the membrane structure and reduces permeability to water-soluble substances.

Integral Proteins

Membrane proteins embedded in or spanning the lipid bilayer; transmembrane proteins extend all the way through and protrude on both sides.

Peripheral Proteins

Membrane proteins attached to only one side of the lipid bilayer.

Cell Adhesion Molecules (CAMs)

Membrane proteins that guide cellular attachment and interaction with other cells.

Ribosomes

Structures composed of RNA and protein that carry out protein synthesis.

Endoplasmic Reticulum (ER)

An internal transport network; Rough ER has ribosomes and synthesizes proteins, while Smooth ER lacks ribosomes and functions in lipid synthesis, fat absorption, and drug metabolism.

Golgi Apparatus

An organelle that modifies, refines, packages, and transports proteins received from the rough ER.

Vesicles

Membranous sacs that store or transport materials within or between cells.

Mitochondria

Organelles that carry out cellular respiration and produce ATP from nutrients; contain inner folds named cristae.

Lysosomes

Organelles containing digestive enzymes that break down nutrients, debris, worn-out cell components, and toxins or drugs.

Peroxisomes

Organelles containing enzymes that break down fatty acids and hydrogen peroxide and detoxify alcohol.

Microfilaments

Actin-based cellular structures that aid in cell movement.

Microtubules

Tubulin-based tubes that provide structural support, intracellular transport, and assistance in cell division.

Centrosome

A central organelle containing two centrioles that organizes and distributes chromosomes during cell division.

Cilia

Short motile projections that move fluid across cell surfaces.

Flagellum

A cellular projection that propels a sperm cell.

Nucleolus

A dense body within the nucleus that produces ribosomes.

Chromatin

Fibers composed of DNA and protein carrying genetic information within the nucleus.

Passive Transport

Membrane transport mechanisms (diffusion, facilitated diffusion, osmosis, filtration) that move materials down gradients without requiring cellular energy.

Active Transport

Membrane transport mechanisms that move substances from lower to higher concentration through carrier proteins using ATP energy.

Diffusion

The movement of molecules or ions from a region of higher concentration to lower concentration down a concentration gradient.

Facilitated Diffusion

Passive movement of substances across a membrane through carrier proteins or ion channels from higher to lower concentration.

Osmosis

The movement of water across a selectively permeable membrane toward the side with a higher concentration of impermeant solute.

Osmotic Pressure

The pressure associated with the tendency of water to move by osmosis, which increases as impermeant solute concentration increases.

Isotonic Solution

A solution with the same osmotic pressure as body fluids, such as a $0.9\%$ NaCl solution.

Hypertonic Solution

A solution with higher osmotic pressure than body fluids that causes cells to lose water and shrink.

Hypotonic Solution

A solution with lower osmotic pressure than body fluids that causes cells to gain water and swell.

Filtration

The movement of water and small solutes through a membrane caused by pressure, with hydrostatic pressure as the driving force.

Na+/K+ ATPase

An active transport carrier protein that uses ATP to move $3\text{ Na}^+$ out of the cell and $2\text{ K}^+$ into the cell against their concentration gradients.

Endocytosis

An active transport process that brings material into the cell; encompasses pinocytosis (liquids), phagocytosis (solids), and receptor-mediated endocytosis.

Exocytosis

An active transport process that releases material out of the cell.

Cell Cycle

The series of changes a cell undergoes from the time it forms until it divides, consisting of interphase, mitosis, and cytokinesis.

Telomeres

Repeated DNA sequences at chromosome tips that act as cellular clocks by shortening with each cell division.

Interphase

A stage of cellular growth and synthesis comprising G1 and G2 (growth and organelle duplication) and S phase (DNA replication).

Mitosis

The division of the cell nucleus, partitioned into prophase, metaphase, anaphase, and telophase.

Cytokinesis

The division of the cytoplasm, facilitated by a cleavage furrow that pinches the cell into two daughter cells.

Differentiation

The process through which a cell becomes specialized in structure and function.

Stem Cells

Undifferentiated cells capable of dividing indefinitely without specializing.

Progenitor Cells

Partially specialized daughter cells of stem cells that retain the ability to produce fully specialized cells.

Apoptosis

Programmed cell death that removes damaged, excess, or unneeded cells during normal development and tissue maintenance.

Intracellular Fluid (ICF)

All water and electrolytes enclosed inside cells, constituting approximately $63\%$ of total body water; high in potassium, phosphate, and magnesium.

Extracellular Fluid (ECF)

All water and electrolytes outside cells, constituting approximately $37\%$ of total body water; high in sodium, chloride, and bicarbonate.

Transcellular Fluid

A subcompartment of extracellular fluid found in specialized cavities, including cerebrospinal fluid, synovial fluid, eye fluids, serous fluid, and exocrine gland secretions.

Osmoreceptors

Sensory receptors in the thirst center of the hypothalamus that detect increases in extracellular fluid osmotic pressure.

Antidiuretic Hormone (ADH)

A hormone that increases the permeability of the distal convoluted tubules and collecting ducts to increase water reabsorption and reduce urine volume.

Aldosterone

A adrenal hormone that increases sodium reabsorption and promotes potassium excretion in the kidneys.

Parathyroid Hormone (PTH)

A hormone that increases calcium ion concentration in extracellular fluid.

Acid

A substance that releases hydrogen ions ($\text{H}^+$) in water.

Base

A substance that releases ions (such as $\text{OH}^-$ or $\text{HCO}_3^-$) that bind with $\text{H}^+$ and reduce hydrogen ion concentration.

Chemical Buffer Systems

Systems (bicarbonate, phosphate, and protein) that act almost immediately to minimize pH changes by converting strong acids or bases into weaker forms or by binding/releasing $\text{H}^+$.

Normal Blood pH

The tightly regulated physiological arterial blood pH range of $7.35$ to $7.45$.

Acidosis

A state in which blood pH falls below $7.35$.

Alkalosis

A state in which blood pH rises above $7.45$.

Respiratory Acidosis

Acidosis caused by $\text{CO}_2$ retention from reduced ventilation or airway obstruction.

Metabolic Acidosis

Acidosis caused by a buildup of nonrespiratory acids or loss of bases, as seen in kidney disease, diarrhea, or diabetes.

Respiratory Alkalosis

Alkalosis resulting from excessive $\text{CO}_2$ elimination due to hyperventilation.

Metabolic Alkalosis

Alkalosis resulting from loss of $\text{H}^+$ or gain of base, such as from vomiting, gastric drainage, diuretics, or excess antacids.