COLLEGE PHYSICS - BIOLOGY 2E - Chapter 4: Cell Structure and Function

Cell Membrane

Encloses the cell and regulates the passage of substances.

Cytoplasm

The internal contents of the cell.

DNA

Genetic material carrying hereditary information.

RNA

Involved in various aspects of gene expression and regulation.

Ribosomes

Cellular machinery for protein synthesis.

Proteins

Perform a vast array of functions within the cell.

Light Microscope

Utilizes light photons to illuminate objects, viewed through lenses. Provides a visible image for general observation.

Electron Microscope

Employs electrons to illuminate objects, offering higher magnification and resolution.

Scanning Electron Micrograph (SEM)

Generates a 3D image, which can be colorized. Useful for observing surface structures.

Transmission Electron Micrograph (TEM)

Produces an image of a very thin cross-section (slice) through the cell, revealing internal structures.

Prokaryotes

Organisms that lack a membrane-bound nucleus and other membrane-bound organelles; their chromosomes are located in the nucleoid.

Nucleoid

A dense area within the cytoplasm of prokaryotes where their chromosomes are located.

Eukaryotes

Organisms that possess a membrane-bound nucleus, which contains all their chromosomes, and other membrane-bound organelles.

Bacteria

Unicellular prokaryotic cells.

Archaea

Unicellular prokaryotic cells, often found in extreme environments.

Eukarya

Composed of eukaryotic cells; can be unicellular or multicellular organisms.

Extremophiles

Organisms that thrive in environments at the planetary extremes of conditions (e.g., temperature, pH, mineral concentrations, salt concentrations, pressure, oxygen levels, light/dark conditions).

Mars

Fourth planet, arid, rocky, and cold, with most water as ice and a thin, mostly CO\_2 atmosphere. A candidate for microbial life.

Europa (Moon of Jupiter)

Ice shell with a global subsurface ocean, rocky core with active geological processes. A candidate for microbial life.

Enceladus (Moon of Saturn)

Ice shell with a global subsurface ocean, rocky core with active geological processes, and water rich in organic molecules. A candidate for microbial life.

Plasmids

Small, circular DNA molecules carrying accessory genes, often found in prokaryotes.

Cell Wall

A tough, fibrous outer layer surrounding the plasma membrane in most prokaryotes (and plant cells), providing structural support and protection.

Cytoskeleton

Composed of long, thin protein filaments, providing structural support in prokaryotic and eukaryotic cells.

Flagella

Tail-like structures on the cell surface of some prokaryotes that spin like a propeller for movement.

Glycocalyx

An additional layer outside the cell wall in many prokaryotes, composed of glycolipids, forming a capsule or slime layer.

Compartmentalization

The breaking up of a eukaryotic cell's large volume into several smaller, membrane-bound organelles, allowing for separation and efficiency of chemical reactions.

Chloroplast

(Plant-specific) Site of photosynthesis.

Large Central Vacuole

(Plant-specific) Stores water, nutrients, and waste, helps maintain turgor pressure.

Plastids

(Plant-specific) A group of organelles including chloroplasts, chromoplasts, and amyloplasts.

Plasmodesmata

(Plant-specific) Channels that directly connect the cytoplasm of adjacent plant cells, allowing for communication and transport.

Centrioles

(Animal-specific) Components of the centrosome, involved in cell division.

Lysosome

(Animal-specific) Contains digestive enzymes for waste processing and recycling.

Centrosomes

(Animal-specific) Main microtubule-organizing center in animal cells.

Gap Junctions

(Animal-specific cell connections) Provide direct channels for communication, allowing passage of ions and small molecules.

Tight Junctions

(Animal-specific cell connections) Watertight seals between cells, preventing leakage of extracellular fluid.

Nuclear envelope

Double membrane surrounding the nucleus in eukaryotic cells.

Nucleolus

Site of ribosome synthesis within the nucleus.

Chromosomes

Structures containing genetic material (DNA) within the nucleus.

Nucleus

Contains all chromosomes and regulates cell activities in eukaryotic cells.

Rough Endoplasmic Reticulum (RER)

Involved in protein synthesis and modification, studded with ribosomes.

Smooth Endoplasmic Reticulum (SER)

Involved in lipid synthesis, detoxification, and calcium storage.

Golgi apparatus

Modifies, sorts, and packages proteins and lipids for secretion or delivery to other organelles.

Peroxisome

Involved in metabolic processes, breaking down fatty acids and detoxifying harmful substances.

Mitochondrion

Site of cellular respiration, producing ATP.