CELL THEORY

four humours

blood, phlegm, black & yellow bile

robert hooke

coined the term cell by slicing wine cork

antoine van leeuwenhoek

microscopist who first observed microorganisms and cells are alive

matthias schleiden & theodor schwann

formulated the first two postulates of cell theory

rudolf virchow

discovered third postulate of cell theory

postulate 1

cells are the fundamental unit of life

postulate 2

all living things are made up of cells

postulate 3

cells come from pre-existing cells

postulate 4

cells contain DNA that is passed on during division

prokaryotic cells

cells found in bacteria that do not contain a nucleus and any membrane-bound organelles

what prokaryotic cells need to function

ribosomes and DNA, they eat to multiply

DNA in prokaryotic cells

located in the cytoplasm

eukaryotic cells

more complex, and larger cells that contain nucleus

endosymbiotic theory

organelles in eukaryotic' cells were once prokaryotic microbes; mitochondria was eaten by the cell

plant cells

has the presence of a cell wall for them to stay rigid

cellular membrane

outermost layer of the animal cell that serves as anactive barrier for protection that blocks organelles from the external environment

classical model of cellular membrane

assumed all membranes had uniform thickness and constant lipid-protein ratio

fluid-mosaic model of cellular membrane

structures of protein are scattered and not uniform, with antenna-like structures called receptors

transport protein

undergo conformational change but can only change as long as it still accommodates the shape destined for the molecule

channel proteins

tunnels that have fixed shape that only accommodate certain molecules

what has selective permeability

cell membrane and its transport & channel proteins

receptors

gather signals from neighboring cells to attract molecules needed to function

phospholipid bilayer

makes up the cell membrane, critical for cell to function

phosph. bilayer HEAD

the hydrophilic phosphate group that keeps the structure together

why is phosphate group (head) hydrophilic

it has to interact with other organelles

phosph. bilayer TAIL

saturated fatty acids freeze fast (straight line), unsaturated (bent) can remain liquid

nucleus

protects the DNA and genetic material

outermost shell

nuclear envelope, nuclear pores, nucleolus, chromatin, nucleoplasm, endoplasmic reticulum

nuclear envelope

entrance of molecules and contains a matrix that verifies if they can enter or exit cell

nuclear pores

matrix pulls both phosph. bilayers inward to create way for ribosomes and mRNA to EXIT

nucleolus

cell’s core that synthesizes ribosomes to create proteins

chromatin

uncoiled/unwound DNA

nucleoplasm

gel-like fluid enclosed within the nuclear envelope and maintains the nucleus’ shape

endoplasmic reticulum

all products of nucleolus exit from the pores and end up here

RBC modification

biconcave disc shape to hold more oxygen and hemoglobin

microvilli

finger-like projections on cell’s surface to increase surface area

neuron modification

stellate shape that allows fast transportation of information to and from many nerve fibers

flagella

whip/tail (containing a lot of mitochondria) of sperm to assist them in swimming

chromatopores

pores planted with pigments that allow them to change colors

root hairs

allow roots to fit in the most cramped spots to absorb water

plasmodesmata

mechanism for plant cells to communicate with each other since there’s a cell wall that prevents them from doing so