Biology Unit 2 - Life in its Simplest Form Cell Structure & Viruses

Cell Theory

Cells are the basic structural unit of all life; all living things are composed of cells; cells can only be produced by other cells.

Prokaryotic Cells

Single-celled organisms that lack a nucleus and membrane-bound organelles; examples include bacteria and archaebacteria.

Eukaryotic Cells

More complex cells with a membrane-bound nucleus; can be single-celled or multicellular, such as cells from plants and animals.

Endosymbiosis Theory

The theory that eukaryotic cells evolved from prokaryotic cells through a mutualistic relationship.

Lytic Cycle

A viral reproductive cycle in which the virus invades a host cell, replicates itself, and causes the host cell to burst, releasing new viruses.

Lysogenic Cycle

A viral reproductive cycle in which the viral DNA/RNA incorporates into the host cell's chromosome and replicates without destroying the host.

Plasmid

An extrachromosomal piece of DNA often found in bacteria; can carry genes such as those for antibiotic resistance.

Cytoplasm

The water-based liquid interior of the cell that holds all soluble materials and organelles.

Ribosomes

Cellular structures responsible for protein synthesis; consist of rRNA and proteins.

Mitochondria

Organelles known for ATP synthesis through cellular respiration; have a double membrane and possess their own DNA.

Chloroplast

Organelles in plant cells that conduct photosynthesis, converting light energy into chemical energy.

Vesicle

A small membrane-bound sac that transports proteins and other substances within a cell.

Cytoskeleton

A fibrous network that maintains cell structure and aids in intracellular transportation.

Endocytosis

The process by which a cell takes in materials by engulfing them in a vesicle.

Exocytosis

The process by which a cell expels materials using vesicles that fuse with the cell membrane.

Carbohydrates

Organic compounds that serve as an energy source and play a role in cell recognition.

Eukaryotic Organelles

Specialized structures within eukaryotic cells that perform distinct functions.

Microscopy

Techniques used to visualize and study the structures of cells; includes light microscopy and electron microscopy.

Viruses

Non-cellular infectious agents that replicate only inside host cells and can have RNA or DNA as genetic material.

Nucleus

The membrane-bound organelle that contains the cell's genetic material (DNA).

Golgi Apparatus

An organelle that modifies, sorts, and packages proteins and lipids for secretion or use within the cell.

Chitin

A structural polysaccharide found in the cell walls of fungi.

Cell Wall

A rigid outer layer found in plant cells, fungi, and prokaryotes that provides support and protection.