Homeostasis & Enzymes

Vocabulary flashcards covering essential terms related to homeostasis mechanisms and enzyme structure, function, and regulation.

Homeostasis

The process by which an organism maintains stable internal conditions necessary for cell survival and proper function.

Receptor (Sensor)

A structure that detects changes (stimuli) in the internal environment and sends information to a control center.

Effector

A muscle or gland that receives signals from the control center and acts to counteract deviations from the normal state.

Negative Feedback Mechanism

A regulatory loop in which a change in a variable triggers responses that reverse the change and restore stability.

Hypothalamus

Brain region acting as a homeostatic control center, regulating body temperature, water balance, and many other processes.

Thermoreceptor

A receptor that detects changes in body temperature.

Shivering

Rapid muscle contractions that generate heat to raise body temperature when it falls below normal.

Vasodilation

Expansion of skin arterioles that increases blood flow to the skin, promoting heat loss when the body is too hot.

Enzyme

A biological catalyst (protein) that speeds up chemical reactions without being consumed.

Catalyst

A substance that increases the rate of a chemical reaction while remaining unchanged at the end of the reaction.

Activation Energy

The minimum amount of energy reactants must absorb to start a chemical reaction; lowered by enzymes.

Amino Acid

The building block of proteins; chains of amino acids form enzymes and other proteins.

Active Site

The specific region of an enzyme where the substrate binds and the reaction occurs.

Enzyme Specificity

The characteristic whereby each enzyme catalyzes only one particular reaction or type of reaction.

Induced Fit Model

Concept that an enzyme changes shape slightly to “hug” the substrate, improving catalytic efficiency.

Denaturation

Permanent alteration of an enzyme’s 3-D structure (often by heat or pH extremes) that destroys its activity.

Optimum Temperature

The temperature at which a particular enzyme’s activity is maximal.

Optimum pH

The pH value at which a specific enzyme functions most effectively.

Substrate Concentration (Saturation Point)

Amount of reactant available; enzyme activity rises with substrate concentration until all active sites are occupied (saturation).

Nervous & Endocrine Systems

The two major body systems that monitor internal conditions and coordinate responses to maintain homeostasis.