Term
| DNA is composed of what monomer? |
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Definition
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Term
| What are the three units to a nucleotide? |
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Definition
1. Deoxyribose (ring-shaped)
2. Phosphate group
3. Nitrogenous base |
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Term
| Identify the 4 different types of nitrogenous bases. |
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Definition
| Adenine, Thymine, Cytosine, Guanine |
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Term
| Identify the 2 groups that nitrogenous bases can be sorted into. Explain why they are sorted into these particular groups. |
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Definition
| T & C are called pyrimidines because they are single-ringed structures. A & G are purines because they are double-ringed structures. |
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Term
| What units make up the backbone of DNA? |
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Definition
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Term
| Explain complementary base pairing and the bases involved. |
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Definition
| These pairings are due to the sizes of the bases and their abilities to form hydrogen bonds with each other. A & T; C & G |
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Term
| Explain the steps of DNA replication. |
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Definition
1. Two strands of the double helix seperate
2. Nucleotides line up one at a time across from the old strand.
3. Enzymes link the nucleotides together to form the daughter strands. |
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Term
| What enzyme is involved in attaching nucleotides together? |
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Definition
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Term
| Compare and Contrast DNA & RNA |
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Definition
DNA is made of deoxyribose and RNA ribose.
DNA forms a double-helix and RNA a single sometimes twisted strand.
In DNA, A pairs with T. In RNA, A pairs with U |
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Term
| Identify and describe the 3 types of RNA |
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Definition
mRNA- Transfers DNA to RNA.
tRNA- translates the three-letter codons of mRNA to amino acids.
rRNA- holds the tRNA and mRNA together |
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Term
| What is a codon? How is it different from an anticodon? |
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Definition
Codon- three-base "word" that codes for an amino acid
Anticodon- in tRNA are complementary to a three-letter codon in mRNA |
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Term
| Explain how mRNA is spliced before it leaves the nucleus. What kind of cell does this happen in? |
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Definition
| Happens in a eukaryotic cell. Before the RNA leaves the nucleus, the introns are removed and the exons are joined together, producing an mRNA molecule with a continuous coding sequence. |
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Term
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Definition
| A mutation is any change in the nucleotide sequence of DNA. |
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Term
| What are the main causes of a mutation? |
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Definition
| Mutations may occur when errors are made during DNA replication, or when errors are made during chromosome crossovers in meiosis. |
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Term
| What is the difference between a silent mutation and an expressed mutation? |
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Definition
| A silent mutation doesn't cause a noticeable change because the mRNA codon isn't changed so it forms a different amino acid. |
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Term
| Explain the three types of mutations, and mention which kinds are the worst. |
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Definition
Base substitution- less harmful, replaces one base or nucleotide with another.
Base insertion- Adding a base
Base deletion- Deleting a base
More dangerous because adding or subtracting nucleotides may alter the triplet groupings of the genetic message. |
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Term
| What is a mutagen? Give an example. |
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Definition
A mutagen is a physical or chemical agent that causes mutations.
Ex. x-rays or UV light |
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