Question

1. Prokaryotes lack some parts found in eukaryotic cells, including which item? a. a nuclear membrane b. DNA c. one or more chromosomes d. a plasma membrane e. all of the above 2. Which of the following statements best describes most bacteria? a) They are generally harmful. b) They are limited to living in a few habitats. c) They are very common in the environment. d) They are responsible for the common cold." 3. Which statement about biofilms would lose points on an exam? a. Growth is due to signaling molecules recruiting cells. b. Cells secrete sticky proteins and polysaccharides. c. Damage to industrial equipment costs billions. d. Nutrients and wastes travel through channels. e. They are uncommon in nature. 4. In what type of environment would you find extreme halophiles? a. ice b. hot springs c. very salty water d. anoxic swamps e. a rain forest 5. Which gets its energy from sunlight and its carbon from ingesting other organisms? a. photoautotroph b. chemoautotroph c. photoheterotroph d. chemoheterotroph 6. If you were given a microscope slide with a sample from a habitat rich in bacteria and nitrogen, you would expect to see a. peptidoglycan. b. heterocysts. c. filaments. d. halophiles. e. biofilms.

Answer 1

1. a. correct option- nuclear membrane- prokaryotic cells lacks nucleus and bound organelles. They only conrain a single chromosome with circular DNA.

2. c. correct option- they are very common in environment- most of the common bacteria are E. coli and mycobacterium.

3. correct option- e. they are uncommon in nature- it would lose points in exam because biofilms are ubiquitous in nature and forms on almost all surfaces immersed in natural aqueous environments.

4. correc option- c. - very salty water- this is because halophile is an extremophile bacteria which needs high salty environment to live in. They need 2M salt concentration and are seen in places like dead sea. Eg- Salinibacter ruber

5. correct option- c) photoheterotroph- they gets energy from light and consume carbon from other organisms as they cannot utilize carbon dioxide form air.

6. correct option- b) heterocycts- they are heterocytes which are nitrogen fixing cells formed from nitrogen starvation from cyanobacteria. and they fix nitrogen in environment using nitrgenase. Hence heterocysts is observed on the slide.

7. correct option- d) sick- this is a zoonotic disease affecting the eyes of dogs and makes them lethargic.

8. correct option- e) extreme thermophiles- they are bacteria that thrive in extreme hot environment( 41 and 122 degree C) and gets killed in normal temperature.

9. correct option- b) providing bioluminscence - deep sea fish such as angler fish has bioluminescent bacteria that lives on thier head called esca which is in a symbiotic relationship and gets protection and nutrients in return.

10. correct option- e) extreme thermophiles- bacteria called thermus aquaticus which an extreme thermophile helps in dna synthesis that are carried out by dna polymerase enzymes that are obtained from these bacteria and these polymerases are heat stable which means they can withstand high temperatures while using pcr.

11. correct option- a) there are archea in your mouth- because archaea have branched hydrocarbon chains attached to glycerol by ether linkages.

12. correct option- e) all of the above could occur - In soil the bacteria helps in decomposition of organic matter as in case of nitrogen fixing bacteria and in pcr without the bacteria thermus aquaticus there wont be dna polymerase enzymes for dna synthesis to occur. Bacteria breaks down the nutreints in soil and without methanogens less methane would be produced. Hence all of the above can occur.