Topic 5: Introduction to Cells; Biological Membranes

Robert Hooke

observed cork (dead cell tissue), observed blocks and called them “cella” (“small room”

Anton van Leuweenhoek

observed “animalcules” (algae) in pond water and was the first to describe living cells using a microscope

Henrietta Lacks

African American woman whose cancer cells were taken without her consent, leading to the creation of the HeLa cell line

prokaryotic cell

cell that lacks a nucleus and membrane-bound organelles (bacteria, archaebacteria)

eukaryotic cell

complex cell with a nucleus and membrane-bound organelles (protists, fungi, plants, animals)

nucleus

unique to eukaryotic cells, repository of cell’s genetic information (DNA), specialized environment for DNA replication and gene expression

cytoplasmic organelles

membrane-bound structures in the cytoplasm that carry out specific tasks

nucleoplasm

gel-like substance within the nucleus that supports and suspends the organelles and genetic material (nucleotides, enzymes)

organelle

specialized subunit within a cell with a specific function, often enclosed by membranes

mitocondria

“powerhouse” of the cell; site of most ATP synthesis

chloroplasts

unique to plant cells; site of photosynthesis

lysosomes

“trash can” of the cell; has enzymes that digest macromolecules

vacuoles

store nutrients and wastes

endoplasmic reticulum

network of membranes involved in protein and lipid synthesis

Golgi apparatus

responsible for modifying, sorting, and packaging proteins and lipids for secretion or delivery to other organelles

cytoskeleton

three networks of filaments that function as the “bones and muscles” of eukaryotic cells (microtublues, microfilaments, intermediate filaments)

plasma membrane

separates cells from external environment

integral (intrinsic) membrane protein

membrane protein that spans the plasma membrane; involved in transport of molecules across the membrane

peripheral (extrinsic) membrane protein

membrane protein that is not embedded in the lipid bilayer but is loosely attached to the exterior or interior surfaces of membranes, involved in signaling and structural support