Term
Given what you know about DNA replication, which of the following is most likely?
1) More mutations are created on the lagging strand.
2) More mutations are created on the leading strand.
3) Neither strand every creates mutations during replicaiton. |
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Definition
| 1) More mutations are created on the lagging strand. |
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Term
| Gene X encodes a protein. Why is it worse for the cell to have a chemically-induced mutation in the DNA of Gene X than it is to have a chemically-induced change in the protein encoded by Gene X? |
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Definition
| A change in Gene X will change the function of every protein Gene X made. |
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Term
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Definition
| Telomerase prevents shortening of telomeres. It binds to the "overhanging" section of single-stranded DNA and adds deoxyribonucleotides to the end of the parent DNA, extending it. |
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Term
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Definition
| A mutation is any permanent change in an organism's genetic information. |
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Term
| What do DNA mutations affect? |
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Definition
| DNA mutations change the genotype of the cell. This leads to the production of novel types of mRNAs and proteins and so can affect phenotype. |
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Term
| What are heritable mutations? Somatic mutations? |
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Definition
| Heritable mutations affect the germ line so that they can be passed on to the next generation. Non-heritable mutations are called somatic mutations. |
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Term
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Definition
| Change in nucleotide that does not change amino acid specified by the codon. Change in genotype but no change in phenotype. |
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Term
| Missense (Replacement) Mutation |
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Definition
| Change in nucleotide that changes the amino acid specified by the codon. Change in primary structure of protein. |
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Term
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Definition
| Change in nucleotide that results in early stop codon. Premature termination - polypeptide is truncated. |
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Term
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Definition
| Addition or deletion of a nucleotide. Reading frame is shifted. Massive missense. |
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Term
| How does DNA polymerase proofread? |
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Definition
| Physically checks the match between paired bases; mismatches in the DNA warp the helical structure; DNA polymerase pauses and removes the mismatched base. DNA polymerase makes a mistake about every 10 million bp. |
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Term
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Definition
| Inversion occurs when a chromosomal segment detaches, flips, and reattaches to the chromosome. |
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Term
| Chromosomal Translocation |
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Definition
| Occurs when a chromosomal segment detaches and becomes attached to a different chromosome. |
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Term
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Definition
| A change in the number of each type of chromosome present. |
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Term
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Definition
| Addition or deletion of a chromosome. |
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Term
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Definition
| DNA can be broken or altered by various chemicals and types of radiation. For example, UV light can cause thymine dimers to form, causing a kink in the DNA strand. |
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Term
| Nucleotide Excision Repair System |
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Definition
| Recognizes damage to DNA; enzymes remove the single-stranded DNA in the damaged section. |
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Term
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Definition
| Occasionally, a single mismatch will occur in a base pair that does not significantly warp the DNA. Mark the older DNA each cycle with methyl groups to allow id of the new strand. Allows activity of MMR proteins in a small segment of the cell cycle. |
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Term
| Xeroderma Pigmentosum (XP) |
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Definition
| A rare autosomal recessive disease in humans characterized by skin lesions. Caused by mutations of one of several nucleotide excision repair systems. |
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