Chapter 7 Flashcards
(35 cards)
What are the five characteristics of being alive?
- need energy
- produce waste
- respond/adapt to environment
- reproduce
- grow
What is spontaneous generation/abiogenesis?
“Life from not life”
organisms develop from non-living matter
What experiment did Francesco Redi complete?
He took two jars that both contained rotting meat and sealed only one of them. When maggots showed up in the jar that was unsealed, he subsequently disproved abiogenesis.
What was Louis Pasteur’s hypothesis? What experiment did he complete to prove it?
He believed that the “active principle” in the air that was creating micro-organisms was a micro-organism itself.
He filled multiple “swan-neck” flasks w/ nutrient-rich broth and boiled them to expel air and kill microbes.
As the flasks cooled, fresh air entered and moisture condensed in the curve of the neck. Micro-organisms settled in the curve of the neck.
If the air itself were the “active principle”, the flasks should’ve teemed w/ life.
Who suggested the theory of biogenesis?
Rudolf Virchow.
What did Hooke discover?
A cork he was observing under a microscope looked as if it were made up of tiny boxes or rooms; he called them ‘cells’.
What did Leeuwenhoek discover?
He was the first person to describe unicellular micro-organisms (prokaryotes); he called them ‘animalcules’.
What did Schwann say?
All organisms are made of cells.
State the three principles of the cell theory and the scientists that discovered them.
- All organisms are composed of 1+ cells (Schwann).
- The cell is the smallest functional unit of life (Leeuwenhoek).
- All cells are produced from other cells (Virchow).
What is a simple microscope?
Use only one lens, similar to a magnifying glass.
What is a compound microscope?
Uses 2+ lenses placed one on top of the other.
What is a compound light microscope?
A compound microscope used to see objects illuminated by visible light.
What is an electron microscope?
A microscope that illuminates specimens (too small to be seen w/ a light microscope) with a beam of electrons rather than a beam of light.
What is a Transmission Electron Microscope (TEM)?
A beam of electrons is transmitted through an object to produce a 2-D image.
What is a Scanning Electron Microscope (SEM)?
Sweeps a beam of electrons over an object. Electrons bounce back to create a 3-D image.
What is a Confocal Laser Scanning Microscope (CLSM)?
A laser beam is directed at one place after another to form a collection of 2-D images. The images are then “stitched” together w/ computer software to create a 3-D image.
What is a Scanning Tunnelling Microscope (STM)?
A fine metal probe is brought near the specimen. The probe follows surface contours on the objects as electrons flow between the tip of the probe and atoms on the surface of the specimen. The info is interpreted by a computer to create a 3-D image.
Nucleus
Directs the cell’s activities. Stores DNA.
Cell membrane
Holds in the contents of the cell. Regulates what leaves and enters.
Cytoplasm
Keeps the organelles in place.
Vesicles
Membrane sacs that store or transport materials in and out of the cell.
Ribosomes
Read the sequence of mRNA and translate it into proteins.
Lysosomes
Various materials are broken down w/ digestive enzymes.
Rough endoplasmic reticulum
Makes membrane proteins.
