Microbiology Exam 2 Terms – Flashcards
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| What does the cell's genome contain? |
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| Its total genetic potential |
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| What is the cell's genotype? |
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| The sum of all structural and regulatory genes |
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| What affects the cell's genome expression? |
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| The environment |
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| The expressed characteristics of a cell are its _________________. |
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| Phenotype |
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| Do mutations permanently change the DNA genome? |
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| Yes. |
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| True or False: Cenes can be transferred between cells. |
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| True |
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| What re DNA mutations? |
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| Changes in the nucleotide sequence |
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| True or False: Genes can be transferred between cells |
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| True |
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| How does a mutation affect the cell? |
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| A mutation affects the cell by changing the codon, therefore the codon's amino acid, and therefore the resulting protein. |
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| When do base substitutions occur? |
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| Usually during DNA replication |
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| What do frame shifts cause? |
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| Change the resulting amino acid sequence and make nonfunctional proteins |
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| What increases the rate of spontaneous mutations and how? |
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| Mutagens- by damaging the DNA (called induced mutations) |
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| What are the four types of mutagens? |
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| 1.Chemicals that damage nucleotide bases 2. Base analogs- changes codons 3. Intercalating agents- cause base additions 4. Ultraviolet radiation- causes thymine dimers |
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| How does the cell repair thymine dimers? |
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| An enzyme uses light energy |
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| What do proofreading and mismatch repair enzymes find? |
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| Damaged DNA, cut it out and repair it |
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| Over many replications, the cells in a bacterial population will show what? |
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| Genetic diversity |
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| Why do prokaryotic cells immediately express mutations? |
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| Because they are haploid |
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| What are small circles of DNA that can exist outside the chromosome or insert themselves into the chromosome? |
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| Plasmids |
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| What is recombination? |
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| Insertion of new, functional DNA into a cell's chromosomes |
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| What are the means of DNA transfer? |
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| 1. Transformation- naked DNA in the medium can be sucked up by bacteria and integrated into the genome 2. Transduction- bacterial viruses can pick up bacterial DNA and transfer it to newly infected bacterial cells 3. Conjugation- related bacterial cells can transfer DNA through a pilus if they are touching |
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| True or False: Plasmids can replicate independently |
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| True |
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| True or False: Plasmids cannot recombine with chromosomes and pop back out |
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| False. |
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| True or False: All plasmids are the same size and shape. |
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| False, they vary in size from few to many genes |
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| How are plasmids transferred? |
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| Between bacteria through conjugation. |
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| Are transferred genes functional? |
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| Yes |
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| Does DNA transfer move genes separately or in groups of related genes? |
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| In groups of related genes as a set. |
