Biology: Solvent Movement and Gated Channels

Study Notes

Gated Channels: Facilitate movement of water from high to low concentration, controlling ion flow across membranes.
Osmotic Pressure: The force needed to prevent water from moving across a cell membrane is influenced by concentration gradients of solutes inside and outside the cell.

Lipid Soluble Substances: Can diffuse through the phospholipid bilayer directly.
Water-Soluble Substances: Require channels to cross the cell membrane, such as ion channels.

Hypotonic Solutions: Lower solute concentration and higher water concentration compared to cell cytoplasm; can cause cells to swell.
Isotonic Solutions: Equal solute concentrations inside and outside cells; results in no movement of water, maintaining cell shape.
Hypertonic Solutions: Higher solute concentration than cell cytoplasm; can lead to cell shrinkage.

A carrier-mediated transport that enables substances to move across the cell membrane without energy expenditure.

Human body contains 46 chromosomes organized into 23 pairs; 22 pairs are autosomes and 1 pair consists of sex chromosomes.
Chromosomes are made of DNA and proteins, existing as loosely coiled chromatin that becomes tightly coiled during cell division.

Large central organelle surrounded by a nuclear envelope consisting of an inner and outer membrane.
Contains nucleoli, sites for ribosome subunit production.

Also known as cytosol, it is a jelly-like fluid that surrounds organelles within the cell.

Endoplasmic Reticulum (ER): Series of membranes responsible for the synthesis of proteins (Rough ER) and lipids (Smooth ER).
Golgi Apparatus: Modifies, packages, and distributes proteins and lipids produced by the ER.
Lysosomes: Membrane-bound vesicles containing enzymes for intracellular digestion; aid in breaking down materials taken up by endocytosis.
Mitochondria: Energy-producing organelles responsible for ATP generation through aerobic metabolism; characterized by inner and outer membranes with cristae.
Peroxisomes: Contain enzymes to break down fatty acids and hydrogen peroxide, preventing toxicity.

Microvilli: Increase surface area of the cell membrane, enhancing absorption; found abundantly in intestinal and kidney cells.
Centrioles: Critical for cell division, involved in the organization of microtubules within the centrosome; exist in pairs arranged perpendicular to each other.

DNA Structure: Composed of two strands of nucleotides; carries genetic information.
Transcription: The process where DNA is copied into messenger RNA.
Translation: Messenger RNA is translated into proteins, which are essential for various cellular functions.