AP Bio Unit 2 Review

Cell Theory

All living organisms are composed of one or more cells, emphasizing cells as the fundamental building blocks of life.

Basic Unit of Life

The cell is capable of carrying out all life processes like metabolism and reproduction.

Rudolf Virchow

Proposed that all cells arise from pre-existing cells, highlighting the continuity of life.

Prokaryotic Cells

Lack a nucleus and membrane-bound organelles, found in bacteria and archaea.

Eukaryotic Cells

Contain a nucleus and various organelles, allowing for specialized cellular functions.

Nucleus

Stores genetic material (DNA) and regulates cellular activities through gene expression.

Nuclear Envelope

Double membrane surrounding the nucleus with nuclear pores for selective transport.

Ribosomes

Sites of protein synthesis, translating mRNA into polypeptide chains.

Rough Endoplasmic Reticulum (ER)

Synthesizes and transports proteins, studded with ribosomes.

Smooth Endoplasmic Reticulum (ER)

Involved in lipid synthesis, detoxification, and calcium ion storage.

Golgi Apparatus

Modifies, sorts, and ships proteins and lipids received from the ER.

Mitochondria

Generates ATP through cellular respiration, known as the powerhouse of the cell.

Cristae

Inner membrane folds of mitochondria that increase ATP production.

Fluid Mosaic Model

Describes the cell membrane as a dynamic phospholipid bilayer with embedded proteins.

Phospholipids

Form a semi-permeable barrier with hydrophilic heads outward and hydrophobic tails inward.

Transport Proteins

Facilitate substance movement across the membrane for selective permeability.

Receptors

Bind signaling molecules to initiate cellular responses.

Selective Permeability

Allows certain substances to cross more easily, maintaining homeostasis.

Passive Transport

Includes diffusion, osmosis, and facilitated diffusion.

Active Transport

Requires ATP to move molecules against their concentration gradient.

Aerobic Respiration

Converts glucose and oxygen into ATP through Glycolysis, Krebs Cycle, and Electron Transport Chain.

Chloroplasts

Organelles where photosynthesis occurs, converting CO₂ and H₂O into glucose and O₂.

Signaling Pathways

Cells communicate through chemical signals and signal transduction for specific responses.

Types of Signaling

Includes Autocrine, Paracrine, and Endocrine signaling pathways.

Endosymbiotic Theory

The theory that eukaryotic organelles like mitochondria and chloroplasts were once free living prokaryotes that were ingested by a larger prokaryotic host cell.

Endocytosis

The process by which cells internalize substances from their external environment by engulfing them in a membrane-bound vesicle.

Exocytosis

The process through which a cell expels materials by packaging them into vesicles that fuse with the cell membrane and release their contents outside the cell.

Dialysis

Diffusion of solutes across a selectively permeable membrane, often used in kidney dialysis to filter blood.

Light Microscopes

Microscopes that use visible light and lenses to magnify objects, typically up to 1,000 times.

Electron Microscopes

Microscopes that use electron beams instead of light for higher magnifications (up to 2 million times).

Phospholipid Bilayer

Double layer of phospholipids forming the cell membrane, with hydrophilic heads and hydrophobic tails.

Tonicity

The relative solute concentration in a solution affecting water movement across cell membranes.

Isotonic

Solution with the same solute concentration as the cell, resulting in no net water movement.

Hypertonic

Solution with higher solute concentration than the cell, causing water to move out of the cell.

Hypotonic

Solution with lower solute concentration than the cell, causing water to move into the cell.