Term
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Definition
| A distinct sequence of nucleotides forming part of a chromosome. |
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Term
| What do most genes carry instructions for? What is the exception this rule? |
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Definition
| Most genes contain the information needed to direct the synthesis of a single sugar. |
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Term
| What are the proteins used for in cells? |
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Definition
| Proteins are the "molecular workers" of the cell and form many of its cellular structures and the enzymes that catalyze its chemical reactions. |
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Term
| Structural difference of RNA and DNA (number of strands, types of sugars, types of bases) |
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Definition
RNA is single stranded, DNA double
RNA has sugar ribose; DNA deoxyribose
RNA has the base uracil in place of thymine and DNA has thymine. |
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Term
| What are the types of RNA involved in protein synthesis? Describe their functions. |
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Definition
Messenger RNA - carries the code for a protein-coding gene from DNA to ribosomes.
Ribosomal RNA - combines with proteins to form ribosomes, the structures that link amino acids to form a protein.
Transfer RNA - carries amino acids to the ribosomes. |
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Term
| Transcription (location and description) |
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Definition
Nucleus
The synthesis of an RNA molecule from a DNA template (mRNA, tRNA, or rRNA). The enzyme/structure involved is RNA polymerase, RNA with DNA: RNA bases pair with DNA bases as an RNA molecule is synthesized. |
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Term
| Translation (location/description) |
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Definition
| The process whereby the sequence of bases of messenger RNA is converted into the sequence of amino acids of a protein. The ribosome and tRNA are the structures involved. mRNA with tRNA: a codon in mRNA forms base pairs with an anticodon in tRNA. |
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Term
| What does the genetic code do? |
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Definition
| The genetic code translates the sequence of bases in nucleic acids into the sequence of amino acids in proteins. |
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Term
| How many bases specify an amino acid in the genetic code? |
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Definition
| Three bases specify an amino acid in the genetic code. |
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Term
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Definition
| An mRNA triplet in mRNA that codes for each amino acid. A sequence of three bases of messenger RNA that specifies a particular amino acid to be incorporated into a protein, certain codons also signal the beginning or end of protein synthesis. |
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Term
| What is the base sequence of the codon that signifies the start protein? What amino acid does this "start" codon specify? |
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Definition
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Term
| What are the base sequences of the three codons that signify the end of a protein? What happens when the ribosome encounters these? |
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Definition
UAG, UAA, and UGA
The ribosome releases both the newly synthesized protein and the mRNA. |
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Term
| How many different codons specify a single amino acid? |
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Definition
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Term
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Definition
| A sequence of three bases in transfer RNA that is complementary to the three bases of a codon in mRNA. |
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Term
| How do the codon and the anticodon ensure proper delivery and ordering of the amino acids in the protein chain? |
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Definition
| Codons on the mRNA are complementary to those on the anticodon on the tRNA (group of three nitrogen bases). |
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Term
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Definition
| The enzyme that synthesizes RNA. |
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Term
| Three steps of transcription with description. |
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Definition
Initiation - RNA polymerase binds to the promoter region of the DNA near the beginning of a gene, separating the double helix near the promoter.
Elongation - RNA polymerase travels along the DNA template strand, unwinding the RNA double helix and synthesizing RNA by catalyzing the addition of ribose nucleotides into an RNA molecule. The nucleotides in the RNA are complementary to the template strand of the DNA.
Termination - At the end of the gene, RNA polymerase encounters a DNA sequence called a termination signal. RNA polymerase detaches from the DNA and releases the RNA molecule. |
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Term
| What is the promoter? Where is it located? What base sequence does it consist of? |
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Definition
The promoter is a specific sequence of DNA at the beginning of a gene, to which RNA polymerase binds and starts gene transcription.
It is located at the beginning of a gene.
It consists of two parts
1) a short sequence of bases, often TATAA that binds RNA polymerase
2) One to two other sequences called transcription factor binding sites or response elements.
**see book** |
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Term
| How many sides of the DNA molecule serve as a template for the synthesis of RNA? |
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Definition
| One side serves as a template for the synthesis of RNA called the template strand. |
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Term
| What happens to DNA after transcription is complete? |
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Definition
| Completely rewinds into a double helix. |
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Term
| What happens to RNA after transcription is complete? |
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Definition
| Is free to move from the nucleus to the cytoplasm for translation. |
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Term
| What happens to RNA polymerase after transcription is complete? |
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Definition
| May move to another gene and begin transcription once again. |
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Term
| What are the three steps of translation? Describe them. |
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Definition
Initiation - When tRNA and mRNA bind to a ribosome. The preinitiation complex scans the mRNA until it fins a start codon which forms the base pairs with UAC anticodon of the methionine tRNA. A large ribosomal subunit then attaches to the small subunit, sandwiching the mRNA between the subunits and holding the methionine tRNA in its first tRNA binding site. It is now ready for translation.
Elongation - Amino Acids are added one at a time to the growing protein chain.
Termination - A stop codon signals the end of translation. |
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Term
| What is the end product of transcription and translation? |
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Definition
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Term
| What determines the effect of deletion and insert mutations? |
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Definition
| How many nucleotides that are removed or added determines the effect. |
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Term
| What would be the effect of inserting three bases? What would be the effect of deleting three bases? |
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Definition
| The effect of inserting three would add a single amino acid, and deleting three bases would delete a single amino acid. |
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Term
| What would be the effect of inserting or deleting a number of bases that is not a multiple of three? |
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Definition
| It could have catastrophic effects because all of the codons that follow the deletion or insertion will be altered. |
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Term
| What is another name for inserting or deleting a number of bases that is not a multiple of three? |
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Definition
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Term
| Describe four different outcomes of a point mutation |
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Definition
Silent mutation - May be unchanged because the amino acid is not changed.
Neutral Mutation - The new protein may be functionally equivalent to the original because of a similar amino acid produced.
Missence Mutation - Protein function may be changed by an altered amino acid sequence.
Nonsense Mutation - Protein function may be destroyed by a premature stop codon. |
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Term
| Why are mutations essential to evolution? |
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Definition
| These random changes in DNA sequence are the ultimate source of all genetic variation. |
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Term
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Definition
| The process by which information from a gene is used in the synthesis of a functional gene product |
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Term
| What are some examples of genes that are expressed in all cells? |
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Definition
| All cells transcribe tRNA genes, rRNA genes, and genes for ribosomal proteins because all cells need to synthesize proteins. |
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Term
| Provide an example of a gene that is not expressed in all cells. |
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Definition
| The gene for casein which is the major protein in milk is only expressed in mature women. |
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Term
| List the five ways gene expression can be regulated by eukaryotes. |
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Definition
1) Cells can control the frequency at which an individual gene is transcribed.
2) The same gene may be used to produce different mRNAs and protein products.
3)Cells may control the stability and translation of messenger RNAs.
4) Proteins may require modification before they can carry out their functions.
5) Cells can control the rate at which proteins are degraded. |
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Term
| Is uracil a purine or pyrimidine? |
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Definition
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Term
| What is the initiation of transcription? |
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Definition
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Term
| The TATA box is __ bases long. |
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Definition
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Term
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Definition
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Term
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Definition
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Term
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Definition
| Covalent bond between amino acids |
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