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A dichotomous key that distinguishes the five classes of the gram- negative Proteobacteria Answer

A dichotomous key that distinguishes the five classes of the gram- negative Proteobacteria.

  1. a. Anoxygenic photosynthetic bacteria ———————– 2

 

  1. b. Chemoorganotrophic bacteria ——————————– 4

 

  1. a. Purple nonsulfer bacteria ———————————– alpha bacteria

 

  1. a. Purple sulfur bacteria —————————————- 3

 

  1. a. Oxidize sulfur, sheath forming bacteria, found in sewage, blogs and decomposition areas ———— Beta proteobacteria

 

  1. b. Oxidize hydrogen sulfide to sulfur and deposit it internally as sulfur granules (usually within invaginated pockets of the plasma membrane); often they eventually oxidize the sulfur to sulfate, largest group of proteobacteria and mostly intracellular pathogenic ————————— Gamma proteobacteria

 

  1. a. Include predator bacteria that attack other bacteria ———————– Delta proteobacteria

 

  1. b. Smallest group of proteobacteria, slender gram-negative rods, which can be straight, curved, or helical —————– Epsilon proteobacteria

 

 

  1. A dichotomous key that distinguishes the four gram-negative bacteria phyla (i.e. Proteobacteria, Cyanobacteria, Chlorobi, and Chloroflex I)
  2. a. Photoorganotrophic and chemoorganotrophic ——————— Proteobacteria
  3. b. Phototrophic bacteria —————————————————— 2
  4. a. Anaerobic ——————————————————————— 3
  5. b. Aerobic ————————————————————————-4
  6. a. Use hydrogen sulfide, elemental sulfur and hydrogen as electron sources; elemental sulfur produced by sulfide oxidation is deposited outside the cell, obligately anaerobic photolithoautotrophs, non-motile bacteria ——————————————- Chlorobia
  7. b. Can carry out anoxygenic photosynthesis with organic compounds as carbon sources or can grow aerobically as a chemoheterotroph, filamentous, thermophilic, gliding bacteria ———- Chloroflexi
  8. Carry out oxygenic photosynthesis, using water as an electron source for the generation of NADH and NADPH 2, most diverse photosynthetic bacteria group ——————— Cyanobacteria.
  9. A dichotomous key that distinguishes the two gram-positive phyla, Firmicutes and Actinobacteria.
  10. a. High G+ C content—————————- Actinobacteria
  11. b. Low G+C content —————————– Firmicutes
  12. A dichotomous key that distinguishes the remaining bacterial phyla, Planctomycetes, Chlamydiae, Spirochaetes, Bacteroidetes, and Fusobacteria
  13. a. Motile bacteria ————————————-2
  14. b. Nonmotile bacteria —————————— 4
  15. a. Presence of distinctive diderm (double-membrane), and axial flagella (a complex of periplasmic flagella), motile bacteria ————————– Spirochetes.
  16. b. Presence of single membrane, motile or non-motile bacteria ————- 3
  17. a. Obligatory anaerobic, with potent lipopolysachharide and pointed rod ———————– Fusobacteria
  18. a. Obligatory anaerobic, which is mutualistic with mammalian intestine and not pointed rods   —————— Bacteroides.
  19. a. Presence of hold fast, aquatic bacteria found in marine, brackish and fresh water —————- planctomycetes.
  20. b. Absence of hold fast, coexist in an asymptomatic state within specific hosts ——————- Chlamydae.
  21. A dichotomous key that distinguishes the following archaea groupings: Thermophiles, Halophiles, Acidophiles, and Methanogens
  22. a. Archaea group that produce methanogen as metabolic by product ——————————- Methanogen
  23. b. Archaea group that don’t produce methanogen as metabolic by product ———————- 2
  24. a. Archaea that live in high temperature ———————————– Thermophilic
  25. b. Archaea group that live in normal temperature ————————– 3
  26. a. Archaea group that live in low pH ——————————————- Acidophiles
  27. b. Archaea group that live in high pH —————————————- Halophiles

 

 

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Do you think that couples undergoing in vitro fertilization should be allowed to perform whatever genetic tests they wish Answer

Many infertile couples turn to in vitro fertilization to try to have a baby. In this technique, sperm and ova are collected and used to create eight-cell embryos for implantation into a woman’s uterus. At the eight-cell stage, one of the fetal cells can be removed without causing harm to the developing fetus. Once removed, the cell can be genetically tested. Some couples may know that a particular genetic disease runs in their family. They might wish to avoid implanting any embryos with the disease-causing genes. Do you think this is an acceptable use of genetic testing? What if a couple wanted to use genetic testing to select embryos for traits unrelated to disease, such as freckles? Do you think that couples undergoing in vitro fertilization should be allowed to perform whatever genetic tests they wish? Or do you think that there should be limits on what tests can be performed? How do you draw the line between genetic tests that are acceptable and those that are not?

 

 

Pre-implantation genetic testing of embryos, through in vitro fertilization (IVF) techniqie, is a type of new process that allows testing and screening of embryos for genetic abnormalities prior to the embryo being transferred to the uterus (implantation). Pregnancy through in vitro fertilization using pre-implantation genetic testing provides the opportunity for the selection of genetically normal embryos that can enhance the possibility of a successful pregnancy, reduce the danger of a miscarriage, decrease the risk of passing definite genetic diseases to progeny and also provides gender selection for family balancing.

Extending the use of preimplantation genetic diagnosis to screen embryos for non‐clinical traits such as gender, height and intelligence, raises serious moral, legal, and social issues (Dahl, 2003). I think that these techniques should used only to detect the genetic disorders, not for addition or deletion of traits unrelated to disease, such as freckles, widow peak etc. Unfortunately, there are no rules and regulations that limit the method’s use. I think that government should ban the use of pre-implantation genetic diagnosis for addition or deletion of desired traits. Couples undergoing in vitro fertilization should not be allowed to perform whatever genetic tests they wish.

Pre-implantation genetic diagnosis should be allowed only to detect the genetic disorders such as Down syndrome, hemophilia etc. Use of this technique must be limited only for detection of autosomal and sex-linked diseases, not for adding/deleting fashionable traits.

Reference

Dahl, E. (2003) Should parents be allowed to use preimplantation genetic diagnosis to choose the sexual orientation of their children? Human Reproduction, 18(7):1368-1369.