Chapter 4 / 5 Flashcards
Cells
- smallest living units
- display ALL properties of life
Cells were discovered in 1600’s by ______ (in cork)
Robert Hooke
Anton van Leeuwenhoek observed living single-______
-celled organisms
3 Basic Parts Of A Cell
1) cytoplasm
2) nucleus
3) plasma membrane
Plasma Membrane
-controls what goes in/out of cell
Nucleus
- controls cells functions
- stores DNA
Cytoplasm
- contains organelles that carry out special functions, everything w/in membrane EXCLUDING nucleus
- 70% water
Cells surface area to _____ sets the upper limit to its size
volume ratio
Greater the # of ACTIVE cytoplasm the…
-more materials used / wastes produced
Plasma membrane is made up of
lipids & proteins
Greater the surface area the….
FASTER substances are exchanged
As a cell’s diameter increases its volume…
it grows faster than SURFACE area
-perfect sphere has maximum volume
Cells w/ altered shapes may get around _____
constraint
ex. long thin nerve cells
Cell Theory
1) all living things are made of one or MORE cells
2) all cells came from PREEXISTING cells
3) basic living units w/i ORGANISMS
Prokaryotes lack a
nucleus
Eukaryotes are LARGER then
prokaryotes
Eukaryotes contain
MEMBRANE-bound nucleus + other organelles
Colonial- consists of
1) cluster of cells
2) survive independently
Multicellular - cells usually perform
specialized tasks
ex. Plants + Animals
Fluid Mosaic Model**
1) phospholipids make up bulk of membrane
2) DESCRIBES structure of cell membrane***
3) proteins are embedded in the lipid BILAYER
Each phospholipid has a _______ _____ & ______
HYDROPHOBIC head & tail
When surrounded by H2O, phospholipids align as
-lipid bilayer
part of molecule likes water, part DOES NOT
Membrane fluidity varies among…
cells specialized for certain environments
ex. penguins on ice, lipids RESIST freezing
Selectively Permeable:
things pass through membrane
Diffuse through membranes?
INORGANIC molecules, very small
Substances that pass through membranes?
FAT-soluble organic substances
Compounds that pass through certain membrane PROTEINS
WATER-soluble organic
Endocytosis
-move INTO cell of large molecule
Exocytosis
-removal waste of proteins, OUTSIDE cell
Nuclear Envelope
- DOUBLE-layered membrane
- surrounds nucleus
Genetic info passes from DNA —> ___ —>______
RNA —-> proteins
Pores in membrane allow…
RNA to escape
______ carry out work of cell
proteins
Chromosomes
form when DNA + protein change at start of cell division
______ makes Ribosomal RNA
nucleolus
Ribosomes
site of PROTEIN synthesis
Cytoskeleton
- 3D structure fibers
- keeps cell’s shape
- moves materials in cell
3 Types of Fiber
1) microtubules
2) microfilaments
3) intermediate filaments
Microfil A ments
-made of protein actin
Actin
MOLECULES in unrelated organisms are similar, suggests ancient origin
Microtubules
-hollow tubes of protein TUBLIN
Spindle Apparatus
-moves CHROMOSOMES around during mitosis
Intermediate Filaments
- keratin + other proteins
- nails, hair, feathers, skin
- reinforcement
