Chapter 4 Notes BIOLOGY “The Cell”
Chapter 4 Notes BIOLOGY
“The Cell”
4-1 CELLS Science is not static
World is flat Planets revolve around the Earth Only things that we can see, exist
1665 Robert Hooke- England: looked at a thin slice
of cork Where does cork come from? He saw chambers, and called them “cells” Why were the chambers empty?
1665… Anton Von Leewenhoek
Used a single lens microscope to observe pond water
He probably saw paramecium, euglena, and amoebas
Metaboly movements of Euglena.
Cells are the basic units of life
Cell Theory has 3 parts that are accepted by all scientists….
1. All living things are made up of cells 1838 Matthias Schleiden – all plants are
made of cells 1839 Theodor Schwann- all animals are
made of cells
2. New cells only come from other cells
1855 Rudolf Virchow said this …
3. Cells are the basic unit of structure and function of all living things.
Atoms are the smallest part that can exist alone
Cells are the smallest part that can exist alone and be considered “alive”
Technology: define each on yr own Fluorescent Labels Confocal Light microscope Hi Resolution Video Electron Microscope TEM SEM Scanning Probe microscope
Prokaryotes/ Eukaryotes Cells: have a cell membrane, and
have DNA at some point in their lives
Prokaryotes-No nucleus
-Smaller-Have free floating DNA
-Bacteria-Can swim/ glide
Eukaryotes-Have nucleus
-Larger/complex-Specialized
-Some fd uni-cellular org-Some fd multi cellular org
4-2 Eukaryotic Cell Structure Organelles; the mini organs of the
cell
NUCLEUS Nucleus- sends out instructions for making
proteins “the brain” Nuclear envelope- separates the nucleus Chromatin- DNA + protein Chromosomes- thickened chromatin that are
visible during cell division Nucleolus – dense region of the nucleus
where manufacturing of proteins begin
CYTOPLASM Ribosomes- where proteins are assembled ER- where lipid parts needed for cell
membrane are made, also some proteins
Rough ER- is invoved in making proteins, ribosomes are found on its surface Proteins made on these ribosomes, go into the rough er
and are modified Most proteins that are made here will be exported out of
the cell Smooth ER- contains collections of enzymes, ready
for action These enzymes perform specialized tasks like
detoxification of drugs Liver cells contain a lot of smooth ER ? Tylenol, alcohol
CYTOPLASM… Lysosomes: clean up crew
Filled with enzymes, that help digest proteins, lipids, carbs- “get the junk out of the cell”.
Tay Sachs Disease: these don’t function properly
Vacuoles Storage place for water, salts, proteins, carbs In plants, it is VERY LARGE, and holds water
and is under pressure – Making it possible for the plant to support structures like leaves and flowers
Paramecium has a contractile vacuole to pump out excess water
CYTOPLASM… Golgi Apparatus: (discovered by Camillo Golgi)
modifies, sorts and packages proteins, from the ER for storage or secretion outside the cell Customization, finishing touches are put on the
proteins- then they are packed and leave the factory
Mitochondria- “powerhouse” of the cell, converts chemical energy in food, to a compound the cell can actually use- Mitochondria has its own simple circular DNA In humans, Mitochondrial DNA is inherited from
your mom Your heart cells many mitochondria in each cell
Chloroplasts w/ chlorophyll Capture energy from sunlight, and convert it into
chemical energy Contain the pigment chlorophyll
Cytoskeleton: protein filaments that help maintain cell’s shape- also involved in movement Centrioles- help to organize cell division (stars) in
animals cells only Microtubules and filaments: help maintain cell
shape- help amoeba move
Flagellum/ Cilia- For movement or sweeping – throat cells Sperm cells
Cell membrane- both animals and plants p182 Regulates what enters and leaves Provides some protection and support
Cell wall Present in plants, algae, fungi, and most
prokaryotes Porous enough to allow water, oxygen and carbon
dioxide among other substances through Fiber- and bowel movement Strong supporting layer made of cellulose a tough
carbohydrate fiber