Lecture 4 Flashcards
Water accounts for how much of a microbial cell?
70% of their total weight
What elements account for 95% of the dry weight of the cell?
hydrogen, oxygen (from water), carbon, nitrogen, phosphorus and sulfur. 95%
The remaining % of the cell wall require which nutriment?
Potassium, magnesium, calcium, iron, manganese, cobalt, copper, molybdenum and zinc.
What are magnesium, cobalt, copper, molybdenum and zinc considered and why?
Tace element due to the fact that they are required in small amounts.
What is required in larger amounts in terms of elements?
Potassium, magnesium, calcium and iron.
Where is hydrogen obtained from for which the cell favour?
From organic compounds and water.
Where is phosphorus obtained from?
Phosphates
What microbes use CO2 as their sole source of cellular carbon?
Photosynthetic autotrophs and chemosynthetic autotrophs.
What microbes receive their carbon from organic compounds?
Photosynthetic heterotrophs and chemosynthetic heterotrophs.
For what microbes does carbon serve as a dual source of energy, carbon and energy?
Chemosynthetic heterotrophs and photosynthetic heterotrophs.
Some microbe only need one source of energy. What does E. coli require only?
Glucose.
What do we name microbes that require more that one organic compound to grow? Elaborate.
Growth factors. Is any organic compound that a microorganism requires and is essential to their cell material.
Name the three growth factors.
- Amino acids- they are required as constituents of proteins.
- Purines and pyrimidines are required as constituents of nucleic acids.
- Vitamins are required for the functions of enzymes.
Name the organic source of nitrogen.
Amino acids and proteins
Name inorganic sources of nitrogen.
Nitrate, Ammonium, gaseous nitrogen of the air (nitrogen fixation).
Name organic sources of sulfur.
Amino acids cysteine and methionine
Name inorganic sources of sulfur.
Sulfate, sulfide.
True of false. Oxygen is a component of all microorganisms? If false, why? if true why?
True. Oxygen is a elemental constituent of water- part of all microorganism.
True or false. Do all microorganism require molecular oxygen to survive? Elaborate.
False. Not all microorganism require O2 to survive.
When speaking of molecular oxygen, microorganism can be categorized in what categories? Elaborate for each category.
Aerobes- they require O2 to grow.
Anaerobes-they do not require O2 to grow. Some, if exposed to O2 is actually toxic that can kill them. These are named strict anaerobes.
Facultative anaerobes- they can grow in the presence or absence of O2.
Microaerophiles- are considered aerobes, however, grow best in the a concentration of o2 lower than whats found in the air.
What category is E.coli? Anaerobic or aerobic?
Facultative anaerobic
