Chapter 8

Chapter 8 - Dhruv Patel Bacterial And Viral Genetic systems...

Info iconThis preview shows pages 1–4. Sign up to view the full content.

View Full Document Right Arrow Icon
Dhruv Patel Bacterial And Viral Genetic systems 1. Bacteria a. They are prokaryotes i. No nucleus or other membrane bound organelles ii. Reproduce via binary fission (asexual) iii. Single circular chromosome iv. DNA replicates prior to cell division 1. 1 replication origin 2. Culturing Bacteria a. Liquid medium b. Agar Plates have a solid surface to grow on c. You can isolate colonies that arise from single cells 3. Media a. Typically contains a carbon source, essential elements such as nitrogen and phosphorus, certain vitamins, and other required ions and nutrients b. Minimal Medium i. Medium that contains only inorganic salts and a carbon source ii. Cells can only grow on minimal medium only if they can synthesize all the organic molecules they need ie aminoacids 4. 3 types of mutants a. Nutritional Mutants i. Prototroph 1. An organism that can survive on minimal medium 2. Can synthesize all of its organic molecules from simple organic salts and a carbon source ii. Auxotroph-
Background image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
1. an organism that cannot synthesize an essential chemical (e.g. an amino acid) and has a specific nutritional requirement for that chemical.) 2. can only grow with suplimental media 3. Ex: leu- mutant a. A leu + cell can synthesize the amino acid leucine. It does not require leucine in its medium.(prototroph) b. A leu mutant cannot synthesize leucine and cannot grow unless leucine is provided in the medium c. Inorder to identify a leu mutant place bacteria in both media that contains leu and one that doesn’t d. The colonies that don’t grow on the minimal media but do on the supplemental media are the leu mutants
Background image of page 2
b. Resistance mutants i. Mutants that are able to grow in the presence of agens(antibiotics, toxic chemicals or viruses) that kill nonresistant cells ii. Ex: 1. str s is sensitive to streptomycin (an antibiotic). 2. str r is resistant to streptomycin. c. Carbon Source Mutants i. Mutation that prevents a bacteria from using a carbon source as energy ii. lac + is able to use the sugar lactose as a carbon source. iii. lac is unable to use lactose. iv. A lac + cell can grow on medium where lactose is the sole carbon source. A lac cell cannot. d. Important Differences between auxotroph and carbon source mutant i. An auxotroph needs a supplement. It can’t grow without it.( we cant make something we need) ii. e.g. leu requires the amino acid leucine in the medium. iii. A carbon source mutant is unable to utilize a certain carbon source. It can’t grow on it.(a carbon source is present but unable to utilize it) iv. e.g. lac can’t grow on medium where lactose is the sole carbon source. 5.
Background image of page 3

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Image of page 4
This is the end of the preview. Sign up to access the rest of the document.

Page1 / 17

Chapter 8 - Dhruv Patel Bacterial And Viral Genetic systems...

This preview shows document pages 1 - 4. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online