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19 Cards in this Set
- Front
- Back
1. What are the two different types of natural genetic flow? Define each. |
Natural genetic flow: how genes moved within the population |
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2. Which type of gene transfer occurs in bacteria? What about in sexually reproducing organisms? |
Bacteria utilize both horizontal (via plasmids & bacteriophage viruses) and vertical gene transfer |
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3. During vertical transfer, what three processes can lead to a high degree of potential genetic variability of offspring? (Be sure to understand the details of each process and how they contribute to genetic variability.) |
Independent assortment of chromosomes: homologs randomly oriented in metaphase I, anaphase randomly assorts them into daughter cells; 2n combinations when n-> haploid chromosome # (in germ cells) |
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4. What are the five processes that can lead to new genes? List and define each. |
1. Mutation: errors in nucleotide sequence. 2. Gene duplication: region of DNA duplicated; allows one gene to diverge for new function. 3. DNA Shuffling: reassortment during crossing over; different genes combined to form new genes with new functions. 4. Horizontal transfer: genes transferred between organisms like in bacteria. 5. Transposable elements: DNA pops out and re-inserts itself into a new gene -> new gene function or disruption of adopting gene |
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5. Is there currently a cellular mechanism for the generation of brand new DNA (and, therefore, new genes)? |
No, new genes from pre-existing genes |
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6. When does DNA shuffling occur? What functional outcome can occur when DNA shuffling combines two genes? |
DNA shuffling occurs during crossing over in prophase I during meiosis |
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7. Explain the significance of gene duplication in the generation of new genes. How can gene duplication lead to gene families? |
Gene duplication provides genetic novelty; with one gene performing its normal function, the other gene can mutate and change to create a new but related function |
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8. There are more than 200 gene families that are common to all three of the primary domains of life. What does that say about the rough number of functions or activities that are common to all three of the primary domains? |
This says that there are about 200 gene families that are responsible for critical/basic cell function and these gene families have been conserved through time |
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9. Explain why modularity of structure is common in proteins from the same gene family. (Be sure to understand what ‘modularity of structure’ means.) |
Modularity of structure means that the proteins belonging to a gene family have similar 3-dimensional structures. |
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10. What mechanisms can cause disruption or loss of existing genes? (Be sure to understand how each mechanism leads to loss.) |
1. DNA Shuffling: reassortment during homologous recombination (crossing-over) |
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11. What is the most common source of DNA mutation? |
Error during DNA replication (1 bp every 10,000) -> proofreading corrects all but 1 in 1,000,000,000 |
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12. List and define the four different types of DNA mutations. |
1. Silent: no change in amino acid sequence -> typically in wobble position |
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13. Mutations that become part of the multicellular genome must occur in the cells of the germ line. Why? |
Germ line cells are the only ones that are transferred to progeny |
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14. Somatic mutations might affect the individual but cannot affect the population. Why? |
Somatic cells are not passed on during reproduction. In order to affect the population the mutation must occur in a germ cell. |
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15. Low rates of mutation can result in high rates of evolution in single-celled organisms. Why? |
Single-celled organisms reproduce at a very high rate with a high number of offspring. These short generation times speed up the rate of evolution. |
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16. What is ROS? (Where does it come from and what does it cause?) |
Reactive Oxygen Species: chemically reactive molecules containing oxygen species |
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17. What are transposable elements and how can they create new genes? |
Transposons: mobile DNA sequences that colonize genomes and move around within them |
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18. Both loss and gain of DNA occur ______________. The relative rates determine a species’ ____________________. |
constantly; genome size |
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19. The Fugu genome is surprisingly small. Why do scientists think its genome is so small? |
The Fugu genome has lost DNA at a higher rate than it has gained DNA |