Archaebacteria

Question 1

What is archae bacteria?

Answer 1

• They are known as ancient bacteria
• Some of the firsts are discovered in Yellow park’s hot springs and geysers
• They live in extreme and normal environment
• All are unicellular

Question 2

What are the similarities btw archaea and bacteria

Answer 2

• Same shape, size, and appearance
• They reproduce by binary fission
• They move primarily by means of flagella
• Morphological similarities makes it difficult to visually tell them apart
• Archie are more phylogenetically similar to eukaryotic than bacteria

Question 3

Difference

Answer 3

• Unlike bacteria, archaea cell walls does not contain peptidoglycan
• They have various types including pseudopeptidoglycan. (no D amino acid)
• membrane lipids have ether bond instead of ester bond
• Have 70S ribosome but in a different shape
• Have more complex RNA polymerase

Question 4

What are methanogens?

Answer 4

Archaea that produces methane (CH4) as part of energy metabolism
They occupy :
- Marshes and swamp
- Hydrothermal vents
- Animal digestive tracts
- Waste Management facilities

Question 5

What are the types

Answer 5

• Methanogens
• Thermoacidophiles
• Halophiles

Question 6

What are thermoacidophiles

Answer 6

• they live in dark, without oxygen
  -like to live in superheated water with temp. less than 750deg F
• prefers acidic env. pH1-3
• like to live in env. of hydrogen sulfide and dissolved minerals (rotten egg smell)

Question 7

What are inclusion body?

Answer 7

• within the cytoplasm of prokaryotic cells are several kinds of reserve deposit known as inclusions.
• cells may accumulate certain nutrients when they are plentiful and use them when environment is deficient.

Question 8

What are metachromatic granules ?

Answer 8

• Metachromatic granules are large inclusions that stain red with certain blue dyes such as methylene blue.
• Volutin- a reserve of inorganic phosphate that can be used for the synthesis of ATP
• Phosphate rich environment
• Metachromatic granules are found in algae, fungi and protozoa
• Granules are characteristics of Corynebacterium diphtheriae

Question 9

What are carboxysomes

Answer 9

Carboxysomes are inclusions that contain the enzyme ribulose I.5- diphosphate carboxylase
Photosynthetic bacteria uses C02 as their sole source of energy and required the enzyme for CO2 fixation
eg) Nitrifying bacteria, cyanobacteria and thiobacilli

Question 10

What are magnetosomes ?

Answer 10

• prokaryotic organelle that serve as navigational devices in magnetotactic bacteria
  and consist of a membrane-enclosed intracellular crystals of iron mineral
  eg) magnetospirillum magneticum

Question 10

What are gas vacuoles?

Answer 10

Hollow cavities found in many aquatic prokaryotes including anoxygenic photosynthetic bacteria and halobacteria
- Each vacuole consists of rows of several gas vacuoles which are hollow cylinders covered by protein
- They maintain buoyancy so that the cells remain at the depth of water where they receive sufficient amount of oxygen, light and nutrients