Note- Cells
I. Basic Info-
Discovery- 1665- Robert Hooke- named cells- saw dead cells
1675- Anton Van Leeuwenhoek- observed living cells
Cell Theory- Schleiden, Schwann, Virchow mid 1800's
---All living things are made of cells
---Cells are basic unit of structure and function
---Cells come from pre-existing cells
Cell size and shape varies- Form Follows Function
Limit to cell size- volume to surface area ratio
Two kinds of cells-
-----prokaryotic cells- primitive- no real nucleus- no membrane bound organelles
bacteria cells are prokaryotic
----eukaryotic cells- more complex cells- have a real nucleus and membrane bound organelles. All cells except bacteria
II. Basic Eukaryotic Cell Parts
A) Nucleus- control center
contains DNA - threads of DNA are called chromatin
Chromatin threads thicken to become chromosomes when the cell divides
nucleus is surround by nuclear membrane
nucleus contains nucleoli (these make ribosomes)
B) Cell Membrane- outer edge of cell
semi-permeable lets some things in and out
made mostly of lipids with scattered protein molecules
C) Cytoplasm- colloid within the cell- it can move- cytoplasmic streaming
cytoplasm contain many cytoplasmic organelles- structures with specific functions
(many have an outer membrane- these are called membrane bound organelles)
NOTE- not all cells have all these organelles- It depends on the function of the cell
1) ribosomes- structures where proteins are made
those located on ER- bound ribosomes- these make proteins the cell will export
those in cytoplasm- free ribosomes - these make proteins the cell keeps
2) Endoplasmic reticulum- (ER) System of membrane used to move materials
rough ER has ribosomes
smooth ER- no ribosomes
Ques- Why put ribosomes on ER? (Why put "factories" on the "highway")
3) Golgi Apparatus-- prepares proteins for export
4) mitochondria- structures where glucose is burned to release
energy- respiration
mitochondria have their own DNA and can divide to form new
mitochondria (mini-cells)
5) Lysosome- sacs of hydrolytic (digestive) enzymes
---digestion
---used by white blood cells to kill bacteria
----destroy unneeded cells- metamorphosis
6) Microtubules / microfilaments cytoskeleton
gives shape and support to cell / used in movement
7) Cilia and flagella- extend from surface of the cell- used to move the cell or material
cilia- hair like structures
flagella- whip like structure
Plant Cells have structures not found in animal cells
1) Plastids-
------a) chloroplast- contains chlorophyll (green pigment)- place
where
photosynthesis occurs- food is made here
------b) chromoplast- contains pigments that give fruits/flowers their colors
-----c) Leucoplasts- no pigments- used for storage of starch (potato)
2) Central vacuole- large area in center of cell where materials are stored- mostly water.
3) Cell wall- rigid outer covering outside of cell membrane- made mostly of cellulose
cells of wood have very thick cell walls
III. Cell Organization-
unicellular / colonial / multicellular
multicellular- tissues / organs / systems