Ch 6 Flashcards
Autotroph
Can make organic carbon from inorganic carbon (ex. CO2 into sugar, green plants/algae)
Heterotroph
Require premade organic carbon (ex. YOU)
Chemotroph
Break down organic molecules and converts the energy into covalent bonds into ATP. (Ex. Animals)
Phototroph
Convert energy in the sunlight into ATP (green plants, algae, cyanobacteria).
Photoautotroph
Use energy from sunlight to convert it into ATP and then produce organic carbon from inorganic carbon.
Photoheterotroph
Use sunlight to make ATP but require premade organic carbon.
Chemoautotroph
Breaks down organic molecules and converts it into covalent bonds and then into ATP in order to make organic carbon from inorganic carbon.
Chemoheterotroph
Break down organic molecules into ATP, but require organic carbon.
Growth requirements
Nitrogen, oxygen, carbon, and energy .
Growth-limiting nutrient
No more nitrogen means no more growth as the cell cannot grow without protein/DNA.
Nitrogen fixation
Nitrogen (n2) from air converted into ammonia (nh3) found in water or ammonium (nh4)
Why is nitrogen fixation important?
It’s essential for life on the planet and is the basis for crop rotation.
Why can oxygen be toxic?
Oxygen can steal electrons from important cell parts, which causes irreversible damage
To survive in oxygen, a cell must be able to detoxify what? (hint 4 things)
- Superoxide radical
- Peroxide
- Hydroxyl radical
- Singlet oxygen
What do organisms that survive in oxygen have in order to destroy toxic oxygen?
They have vitamins or anti-oxidants (vitamin C, and E) to destroy toxic oxygen. Organisms without any of these will die.
Aerobes
Uses 02 in metabolism
Obligate aerobes
Require oxygen for metabolism
Ex. Mycobacterium tuberculosis
Facultative anaerobes
Considered to be aerobe because it grows best in oxygen, however it can survive without it, as it has metabolic pathways for both anaerobic and aerobic.
Ex. E-coli
Microaerophiles
Uses 02 in metabolism, but not always required, and can only tolerate oxygen in amounts less than the atmospheric concentration (less than 18%; prefer 3-10%) Ex. Helicobacter pylori (live in intestines)
Anaerobes
Do not use 02 in metabolism
Obligate anaerobes
Killed by oxygen
Ex. Clostridium tetani (lives in soil)
Aerotolerant anaerobes
No aerobic metabolism, but can tolerate oxygen as it just doesn’t use it for metabolism. Ex. Lactobacillus acidophilus ( found in milk.)
Psychrophiles
Cold loving, found in snow, ice and cold water. Optimum temp is 10 c which means it never causes disease in humans.
Organisms include algae, fungi, and bacteria.