1. Lecture Notes Flashcards: Homeostasis, Cells, Membranes, and Cell Cycle

Vocabulary flashcards covering key concepts from the lecture notes on homeostasis, cells, membranes, and the cell cycle.

Homeostasis

The body's ability to maintain a stable internal environment despite external changes, achieved through feedback mechanisms.

Negative feedback loop

A regulatory loop that reverses a stimulus to return to a setpoint (e.g., sweating to cool the body).

Positive feedback loop

A regulatory loop that amplifies a stimulus, usually driving a process to completion (e.g., childbirth).

Stimulus

A change in the internal or external environment that triggers a response.

Sensor

A component of a feedback system that detects changes in the environment.

Control center

The part of a feedback system that processes information and directs responses.

Effector

The organ or cell that executes the response to restore homeostasis.

Proximal

Closer to the point of origin in a limb (e.g., shoulder is proximal to the elbow).

Distal

Farther from the point of origin in a limb (e.g., fingers are distal to the shoulder).

Anterior

Front of the body; opposite of posterior.

Posterior

Back of the body; opposite of anterior.

Medial

Toward the midline of the body.

Lateral

Away from the midline; toward the side.

Superior

Above or toward the head.

Inferior

Below or toward the feet.

Sagittal plane

A vertical plane that divides the body into left and right portions.

Lipid bilayer

Two-layer structure of the cell membrane made of phospholipids.

Hydrophilic head

Water-loving part of a phospholipid facing aqueous environments.

Hydrophobic tail

Water-fearing part of a phospholipid facing inward toward the bilayer core.

Protein channel

A membrane protein that forms a pore to allow specific substances to cross the membrane.

Glycolipid

A lipid with carbohydrate groups involved in cell recognition.

Glycoprotein

A protein with carbohydrate groups that aids in cell recognition.

Membrane fluidity

How freely lipid molecules move within the phospholipid bilayer; influenced by temperature and cholesterol.

Cholesterol

A lipid that modulates membrane fluidity and stability across temperatures.

DNA

Deoxyribonucleic acid; the genetic material that stores hereditary information.

Chromosome

A packaging of DNA that organizes genetic material for cell division.

DNA replication

The process of copying DNA prior to cell division.

Ribosome

The molecular machine that translates mRNA into a polypeptide chain (protein).

tRNA

Transfer RNA; delivers specific amino acids to the ribosome during translation.

Amino acid

The building blocks that link together to form proteins.

Protein folding

The process by which a protein assumes its functional 3D shape; misfolding can impair function.

Single-point mutation

A mutation at a single nucleotide in DNA that can alter protein structure and function.

Solute

A substance dissolved in a solvent (e.g., salt in water).

Solvent

The dissolving medium (e.g., water).

Concentration gradient

A difference in solute concentration across a space, driving movement from high to low concentration.

Hypertonic solution

A solution with higher solute concentration outside a cell, causing water to move out and the cell to shrink.

Active transport

Movement of substances across a membrane that requires energy to move against a concentration gradient.

Sodium-potassium pump

Na+/K+ ATPase; an active transporter moving Na+ in and K+ out to maintain ion gradients.

Interphase

The stage of the cell cycle when the cell grows, duplicates DNA, and prepares for division.

Mitosis

Nuclear division resulting in two genetically identical daughter nuclei; includes several stages.

Prophase

First stage of mitosis; chromosomes condense and the spindle forms.

Prometaphase

Mitotic stage where the nuclear envelope breaks down and spindle fibers attach to chromosomes.

Metaphase

Stage of mitosis where chromosomes align along the cell's equator.

Anaphase

Stage of mitosis where sister chromatids separate and migrate to opposite poles.

Telophase

Stage of mitosis where nuclei reform around separated chromatids; cytokinesis often follows.

Desmosome

A cell junction that provides mechanical strength by anchoring adjacent cells.

Gap junction

A cell junction that allows direct chemical communication between neighboring cells.

Collagen

A structural protein that provides tensile strength to tissues.