What are the 5 things something needs to do to be alive?
Grow
Produce
Respond to stimuli (heat, touch)
require energy
produce waste
What is spontaneous generation?
The theory that there was a “life force” in the air that could make living things
What did Francesco Redi do
Completed an experiment that showed spontaneous generation was false in 1668
Experiment was taking pieces of meatand placed them in jars to see if maggots would appear = proving spontaneous generation, some jars were sealed, open, or covered with gauze
What did John Needham do
Conducted experiment which proved spontaneous generation in 1745 (Was flawed and uncontrolled.)
What did Louis Pasteur do and what were the variables
finally refuted spontaneous generation in 1864 and later lead to the modern cell theory
Experiment with s shaped flask that was closed and one that was opened.
- Controlled variables – broth type, flask type, light, temperature
- Manipulated variables – access of dust and particles to the flask;
flask open/closed - Responding variable – ability to grow mold in the broth
When were microscopes invented, where by who and for what
1600s in holland by Anton Van Leeuc`venhoek
Cell Theory states:
- 1) All living things are made up of one or more cells.
- 2) Cells are the smallest unit of life.
- 3) All cells are produced from pre-existing cells through the process of cell division.
- All cells are either prokaryotic or eukaryotic
- Prokaryotic organisms include bacteria
- Eukaryotic organisms include plants , animals, protists and fungus
Different light microscopes
(a) Simple
* Made up of single hand
held lens
(b) Compound
* Combination of two lenses
* 500 x magnification
The electron microscope
since 1930’s
* Illuminates specimen with electrons instead
of visible
light
Two main types of electron
microscopes
Transmission Electron Microscope (TEM)
- Beam of electrons passes through a thin specimen
Scanning Electron Microscope (SEM)
- Electrons bounce off the specimen and creates a
3D image of specimen surface
- Looks only at the surface of the specimen
Confocal Laser Scanning Microscope
Used to study thick specimens
- Laser beam creates optical 2D slices throughLaser beam creates optical 2D slices through objects to create a 3D picture on computerobjects to create a 3D picture on compu
What is an organelle?
a structure within a cell that performs a
specific function. (ex: Cell membrane, Nucleus, Cell wall, mitochondria)
Difference in Plant and Animal cells
Plant cells have chloroplast, amyloplast and a cell wall but Animal cells dont
Tell me about the cell membrane
- One of the most important parts of the cell
- functions include a biological barrier that keeps stuff inside the cell seperate from the outside and a selective filter that allows certain molecules to pass.
-Acts more like a fluid thann solid and is in constant motion
What is the cell membrane made of?
Lipids (fat) that are found in a molecule called phospholipids
Tell me about phospholipids
Made up of ONE hydrophilic (water loving) phosphate head and TWO hydrophobic fatty acid tales (tails, water fearing)
What is the phospholipid bilayer, What does it do.
- Since each phospholipid is made up of a hydrophilic phostphate head (polar) and two hydrophic tales (non polar) they tend to form a bilayer when put into water.
- It seperates contents of the cell from the outside and surrounds each of the organelles to prevent unwanted chemical reactions
Tell me about proteins in the phospholipid bilayer
Contains specialized proteins that help the cell membrane function
What are the two main functions of the phospholipid Bilayer
Acts as a biological barrier
Acts as a selective filter
- Certain molecules can pass though membrane freely while others must be transported across using specialized transport proteins found in membrame
What is brownian motion
All particles in the universe are in constant/random motion
Since the particles are constantly moving they travel towards areas of low concentration
What is passive transport
Cell take advantage of concentration gadients = allow certain molecules to cross PB, moving from high concentration to low
Gradient energy is NOT USED = passive transport
What are three types of passive transport
Simple diffusion
Facilitated Diffusion
Osmosis
what is simple diffusion
- tiny molecules can pass through PB because of this, moving from high [ ] to low [ ] (small enough to fit between phospholipids of bilayer)
What is Facilitated Diffusion
- Not all molecules tiny enough to pass through PB = still move down concentration gradient into cell (but must also use transport proteins)
