Human Phys - Exam 1

Cellular components of protein synthesis

The nucleus, ribosomes, endoplasmic reticulum, and Golgi apparatus are involved in creating proteins.

Transcription

The process in the nucleus where DNA is copied into mRNA.

Translation

The process in the cytoplasm where ribosomes read mRNA and synthesize polypeptide chains.

Primary structure

The specific sequence of amino acids in a protein, formed during translation.

Secondary structure

Local folding of the polypeptide into alpha helices or beta sheets, stabilized by hydrogen bonds.

Tertiary structure

The overall 3D shape of a protein formed by further folding and stabilization of the polypeptide.

Quaternary structure

The assembly of multiple polypeptide chains into a functional protein complex.

Protein packaging

Proteins are folded and modified in the endoplasmic reticulum and then sent to the Golgi apparatus for further modification and sorting.

Signal sequences

Short amino acid tags that direct proteins to their correct cellular locations.

Cytoskeleton

A network of microtubules that provides pathways for vesicle transport within the cell.

Motor proteins

Proteins like kinesin and dynein that transport vesicles along the cytoskeleton using ATP.

Negative feedback

A physiological mechanism that reverses changes to maintain stability in a system.

Sensor

A component that detects changes in a physiological system and sends information to the control center.

Control center

The part of the feedback system that processes information from the sensor and determines the response.

Effector

The component that carries out the response to restore the system to its set point.

Positive feedback

A mechanism that amplifies changes, driving a system further from its set point.

Feedforward

A process that anticipates changes and initiates responses to prevent disruptions in a system.

Blood pressure regulation

An example of negative feedback where sensors detect increased blood pressure and signal the heart to slow down.

Lactation

An example of positive feedback where suckling stimulates milk production and release.

Gibbs's free energy

A measure of the spontaneity of a process, including diffusion through a semipermeable membrane.

Van’t Hoff’s equation

Relates Gibbs's free energy change to concentration differences across a membrane.

Simple diffusion

The movement of molecules from high to low concentration without energy input.

Facilitated diffusion

The process where carrier or channel proteins assist in the movement of larger or polar molecules across a membrane.

Active transport

The movement of molecules against their concentration gradient, requiring energy input.

Plasma membrane

A semipermeable barrier made of a phospholipid bilayer that regulates the entry and exit of substances.

Membrane channels

Proteins that facilitate the movement of specific molecules across the plasma membrane.

Pumps

Membrane proteins that actively transport substances against their concentration gradient using ATP.

ΔG (Gibbs Free Energy)

The change in free energy that determines the spontaneity of a process.

ΔH (Enthalpy)

The change in heat content, which can affect the spontaneity of diffusion processes.

T (Temperature)

The absolute temperature in Kelvin, influencing molecular movement and diffusion rates.

ΔS (Entropy)

The change in disorder; increased entropy generally promotes spontaneity in diffusion processes.