BIOL 2420 Study Guide Exam 1

Flashcards covering key biological concepts from BIOL 2420 Exam 1 study guide, including cell/tissue types, homeostasis, biomolecules, membrane transport, cellular communication, and GI tract functions.

Epithelial Tissue

Covers body surfaces, lines cavities and forms glands; functions in protection, absorption, filtration, excretion, and secretion.

Connective Tissue

Supports, protects, and binds together other tissues; includes bone, cartilage, fat, and blood.

Muscle Tissue

Specialized for contraction, producing movement; includes skeletal, cardiac, and smooth muscle.

Nervous Tissue

Transmits electrical signals rapidly throughout the body; responsible for communication and control.

Body Fluid Compartments

Spaces within the body where fluids are located, such as intracellular fluid (ICF) and extracellular fluid (ECF), which includes interstitial fluid and plasma.

Homeostasis

The maintenance of a relatively stable internal environment despite continuous changes in the external environment.

Negative Feedback

A regulatory mechanism in homeostasis where the response counteracts the original stimulus, returning the variable to its set point.

Regulated Variable

A physiological variable that is maintained within a normal range by homeostatic mechanisms (e.g., body temperature, blood glucose).

Set Point

The ideal value for a regulated variable in a homeostatic system.

Set Range

The narrow range of values around the set point within which a regulated variable is normally maintained.

Receptors (Homeostasis)

Sensors that monitor the environment and respond to changes (stimuli).

Integrating Center

Receives and interprets input from receptors and determines the appropriate response (often the brain or endocrine gland).

Effectors

Respond to the integrating center's signals by carrying out the necessary actions to restore homeostasis (e.g., muscles, glands).

Positive Feedback

A regulatory mechanism where the response enhances or amplifies the original stimulus, pushing the variable further from its set point (e.g., childbirth, blood clotting).

Central Dogma

The fundamental concept that genetic information flows from DNA to RNA to protein.

Biomolecules

Organic molecules essential for life, including carbohydrates, lipids, proteins, and nucleic acids.

Carbohydrates

Organic molecules made of carbon, hydrogen, and oxygen; primarily function as a source of energy (e.g., glucose, starch).

Lipids

Hydrophobic organic molecules including fats, oils, phospholipids, and steroids; function in energy storage, membrane structure, and signaling (e.g., triglycerides).

Proteins

Large, complex organic molecules made of amino acids; perform a wide variety of functions including enzymes, structural components, and transport (e.g., collagen, hemoglobin).

Nucleic Acids

Organic molecules made of nucleotides; store and transmit genetic information (e.g., DNA, RNA).

Hydrophilic

Water-loving; substances that dissolve readily in water due to polar or ionic groups.

Hydrophobic

Water-fearing; substances that do not dissolve in water, typically nonpolar molecules like lipids.

Acidic pH

A pH value less than 7, indicating a higher concentration of hydrogen ions (H+).

Basic (Alkaline) pH

A pH value greater than 7, indicating a lower concentration of hydrogen ions (H+).

Cell Membrane

A selectively permeable phospholipid bilayer that surrounds the cytoplasm of a cell, regulating the passage of substances into and out of the cell.

Tight Junctions

Intercellular junctions that form an impermeable barrier between cells, preventing the passage of substances through the paracellular space.

Desmosomes

Intercellular junctions that act as 'spot welds', anchoring adjacent cells together and resisting mechanical stress.

Gap Junctions

Intercellular junctions that allow direct cytoplasmic communication between adjacent cells, facilitating the passage of small molecules and ions.

Metabolism

The sum of all chemical processes that occur in an organism, including both anabolic and catabolic reactions.

Catabolic Reactions

Metabolic reactions that break down complex molecules into simpler ones, releasing energy (e.g., cellular respiration).

Anabolic Reactions

Metabolic reactions that build complex molecules from simpler ones, requiring energy input (e.g., protein synthesis).

Aerobic Respiration

The process of cellular respiration that requires oxygen to produce ATP, yielding a large amount of energy from glucose.

Anaerobic Respiration

The process of cellular respiration that does not require oxygen, producing a smaller amount of ATP compared to aerobic respiration (e.g., fermentation).

Lipogenesis

The metabolic process by which fatty acids and triglycerides are synthesized from other molecules, typically excess carbohydrates or proteins.

Proteogenesis

The synthesis of proteins from amino acids, also known as protein synthesis.

Gluconeogenesis

The metabolic pathway that results in the generation of glucose from non-carbohydrate carbon substrates such as lactate, glycerol, and glucogenic amino acids.

Aquaporins

Specific channel proteins in the cell membrane that facilitate the rapid movement of water across the membrane.

Tonicity

The ability of an extracellular solution to cause a cell to gain or lose water, depending on the concentration of non-penetrating solutes.

Osmosis

The net movement of solvent (water) molecules across a selectively permeable membrane from a region of higher water concentration to a region of lower water concentration.

Simple Diffusion

The net movement of substances from an area of higher concentration to an area of lower concentration, directly across the membrane, without the aid of membrane proteins.

Facilitated Diffusion

The net movement of substances down their concentration gradient across a cell membrane with the aid of specific transmembrane proteins (channels or carriers), without direct energy expenditure.

Active Transport

The movement of substances across a cell membrane against their concentration gradient, requiring energy expenditure and specific membrane proteins (pumps).

Bulk Transport

The movement of large molecules or large quantities of substances across the cell membrane in membrane-bound vesicles, including endocytosis and exocytosis.

Transcytosis

A type of bulk transport where substances are taken into a cell by endocytosis, moved across the cell, and then released on the opposite side by exocytosis.

Paracellular Movement

The movement of substances between adjacent cells, often through tight junctions or other intercellular spaces.

Transcellular Movement

The movement of substances through the cytoplasm of a cell, crossing both the apical and basolateral membranes.

Channel Protein

A transmembrane protein that forms a pore or channel through the lipid bilayer, allowing specific ions or small molecules to pass down their concentration gradient.

Carrier Protein

A transmembrane protein that binds to specific solutes and undergoes a conformational change to transport them across the membrane.

Primary Active Transport

Active transport that directly uses energy from ATP hydrolysis to move substances against their concentration gradient (e.g., Na+/K+ pump).

Secondary Active Transport

Active transport that indirectly uses energy stored in an ion gradient (established by primary active transport) to move another substance against its concentration gradient.

Endocytosis

A process by which cells take in substances from outside by engulfing them in a vesicle that buds inward from the plasma membrane.

Exocytosis

A process by which cells release substances to the outside by fusing a vesicle containing the substance with the plasma membrane.

Phagocytosis

A type of endocytosis where a cell engulfs large particles or whole cells ('cell eating').

Pinocytosis

A type of endocytosis where a cell takes in fluid and dissolved solutes ('cell drinking').

Receptor-Mediated Endocytosis

A highly specific type of endocytosis where specific molecules bind to receptors on the cell surface, triggering the formation of a clathrin-coated vesicle.

Chemical Force

The force exerted by a concentration gradient that drives the net movement of a substance from an area of higher concentration to an area of lower concentration (e.g., for Na+, K+).

Electrical Force

The force exerted by the membrane potential that drives the net movement of an ion across the membrane based on its charge (e.g., for Na+, K+, Cl-).

Electrochemical Force

The combined influence of the chemical (concentration) gradient and the electrical (membrane potential) gradient on the movement of an ion across a cell membrane.

Equilibrium Potential

The membrane potential at which the electrical force on an ion precisely opposes the chemical force, resulting in no net movement of that ion across the membrane.

Equilibrium Potential for Na+

Typically around +60 mV.

Equilibrium Potential for K+

Typically around -90 mV.

Equilibrium Potential for Ca2+

Typically around +120 mV.

Equilibrium Potential for Cl-

Typically around -70 mV.

Average Membrane Potential (Vm)

The typical resting potential across a cell membrane, often around -70 mV.

Cellular Communication

The process by which cells send, receive, and respond to signals, essential for coordinating cellular activities.

Hydrophobic Ligands

Signaling molecules that are lipid-soluble, allowing them to diffuse across the cell membrane to reach intracellular receptors (e.g., steroid hormones).

Hydrophilic Ligands

Signaling molecules that are water-soluble and cannot cross the cell membrane, binding to receptors on the cell surface (e.g., peptide hormones, neurotransmitters).

Direct Cell Signaling

Signaling via gap junctions, allowing direct cytoplasmic transfer of signaling molecules between adjacent cells.

Paracrine Signaling

Short-range cell signaling where a cell secretes signaling molecules that act on nearby target cells.

Endocrine Signaling

Long-range cell signaling where specialized cells secrete hormones into the bloodstream, which then travel to distant target cells.

Intracellular Receptors

Receptors located inside the cell, typically in the cytoplasm or nucleus, that bind to hydrophobic ligands.

Plasma Membrane Receptors

Receptors located on the surface of the cell membrane that bind to hydrophilic ligands.

Plasma Carrier Protein (Signaling)

Proteins in the blood plasma that bind and transport hydrophobic signaling molecules (like steroid hormones) to make them soluble and extend their half-life.

Mucosa (GI Tract)

The innermost layer of the GI tract wall, involved in secretion, absorption, and protection, often containing glands and lymphoid tissue.

Submucosa (GI Tract)

The layer beneath the mucosa, containing blood vessels, lymphatic vessels, nerves (submucosal plexus), and sometimes glands, supporting the mucosa.

Muscularis Externa (GI Tract)

The muscle layer responsible for peristalsis and segmentation, typically consisting of an inner circular and an outer longitudinal layer of smooth muscle.

Serosa/Adventitia (GI Tract)

The outermost layer of the GI tract wall; serosa is a serous membrane (peritoneum) in the abdominal cavity, while adventitia is fibrous connective tissue in other regions.

Ingestion

The process of taking food into the digestive tract, typically through the mouth.

Digestion

The breakdown of food into molecules small enough to be absorbed, involving both mechanical and chemical processes.

Absorption (GI Tract)

The passage of digested nutrients from the lumen of the GI tract into the blood or lymph.

Defecation (Elimination)

The elimination of indigestible substances from the body in the form of feces.

Stomach Acidity

The highly acidic environment of the stomach (pH 1.5-3.5) created by hydrochloric acid, crucial for activating pepsin, denaturing proteins, and killing bacteria.

Saliva

Fluid secreted by salivary glands containing water, electrolytes, salivary amylase (for carbohydrate digestion), lingual lipase (for lipid digestion), mucin (lubrication), and lysozyme (antibacterial).

Chemical Digestion

The enzymatic breakdown of complex food molecules into their simpler chemical building blocks (e.g., proteins to amino acids, polysaccharides to monosaccharides).

Mechanical Digestion

The physical breakdown of food into smaller pieces, increasing surface area for enzymatic action (e.g., chewing, churning in the stomach, segmentation in the small intestine).

Pancreas (Digestion)

An accessory organ that secretes digestive enzymes (e.g., amylase, lipase, proteases) and bicarbonate into the small intestine to neutralize chyme and aid digestion.

Liver (Digestion)

An accessory organ that produces bile, which emulsifies fats in the small intestine, facilitating their digestion and absorption.

Parietal Cells

Cells in the stomach lining that secrete hydrochloric acid (HCl) and intrinsic factor.

Chief Cells

Cells in the stomach lining that secrete pepsinogen (the inactive form of pepsin) and gastric lipase.

Intrinsic Factor

A glycoprotein secreted by parietal cells in the stomach, essential for the absorption of vitamin B12 in the small intestine.