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28 Cards in this Set
- Front
- Back
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What is an organism's genotype? |
It is the heritable information contained in the sequence of nucleotide bases in DNA |
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What is transcription? |
synthesis of RNA/transfer of info from DNA to RNA |
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What is translation? |
synthesis of protein under direction of RNA/use of info from RNA to make a polypeptide |
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What are the pyrimidines? |
thymine + cytosine |
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What are the purines? |
adenine + guanine |
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During cell divisions that lead from zygote —> adult, individual cells must undergo ________—that is, they must become ______ in ______ and ______ |
During cell divisions that lead from zygote —> adult, individual cells must undergo differentiation—that is, they must become specialized in function and structure |
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What happens during initiation for transcription of a gene? |
Initiation involves the attachment of RNA polymerase to the promoter and the start of RNA synthesis |
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What happens during elongation for transcription of a gene? |
During elongation, the newly formed RNA strand grows. As synthesis continues, the growing RNA molecule peels away from its DNA template, allowing the two separated DNA strands to come back together in the region already transcribed. RNA polymerase adds new RNA nucleotides to RNA |
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What happens during termination for transcription of a gene? |
When RNA polymerase reaches the terminator DNA (which signals the end of the gene), the polymerase molecule detaches from the newly made RNA strand and the gene |
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How does RNA polymerase recognize the start and end of the gene? |
Special DNA sequences mark the start (promoter) and end (terminator) of a gene |
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What does the law of segregation state? |
A sperm or egg carries only one allele for each inherited character because allele pairs segregate from each other during the production of gametes |
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What does tRNA do and how do they do it? |
tRNA molecules match amino acids to the appropriate codons to form the new polypeptide. To do this, tRNA molecules must carry out two functions: 1. Pick up appropriate amino acids 2. Recognize the appropriate condone in the mRNA |
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What does tRNA do and how do they do it? |
tRNA molecules match amino acids to the appropriate codons to form the new polypeptide. To do this, tRNA molecules must carry out two functions: 1. Pick up appropriate amino acids 2. Recognize the appropriate condone in the mRNA |
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What is a tRNA made of? What is its structure? |
tRNA molecule is made of a single strand of RNA consisting of ~80 nucleotides. By twisting and folding upon itself, tRNA forms several double-stranded regions in which short stretches of RNA base pair with other stretches via hydrogen bonds. A single stranded loop at the end of the folded molecule contains a special triplet of bases called an anticodon |
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What does tRNA do and how do they do it? |
tRNA molecules match amino acids to the appropriate codons to form the new polypeptide. To do this, tRNA molecules must carry out two functions: 1. Pick up appropriate amino acids 2. Recognize the appropriate codon in the mRNA |
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What is a tRNA made of? What is its structure? |
tRNA molecule is made of a single strand of RNA consisting of ~80 nucleotides. By twisting and folding upon itself, tRNA forms several double-stranded regions in which short stretches of RNA base pair with other stretches via hydrogen bonds. A single stranded loop at the end of the folded molecule contains a special triplet of bases called an anticodon |
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What does the anticodon do? |
The anticodon triplet is complementary to a codon triplet on mRNA |
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How does a nucleic acid probe work? |
The DNA sample is treated with heat or chemicals to separate the DNA strands. When the radioactive DNA probe is added to these strands, it tags the correct molecules by hydrogen-bonding to the complementary sequence in the gene of interest. |
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What is a nucleic acid probe? |
a radioactively or fluorescently labeled single-stranded nucleic acid molecule used to find a specific gene or other nucleotide sequence within a mass of data. The probe hydrogen-bonds to the complementary sequence in the targeted DNA |
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What is the chromosome theory of inheritance? |
A basic principle in biology stating that genes are located on chromosomes and that the heavier of chromosomes during meiosis accounts for inheritance patterns |
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The chromosome theory of inheritance is based upon what observation? |
Genes segregate; chromosomes come in pairs.
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There are over 100 alleles known for the gene associated with cystic fibrosis. With current technology, it is possible to determine exactly which allele or alleles is/are carried by a person. What is the maximum number of different alleles that any person can carry? |
2 |
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Why are lethal dominant alleles so much more rare than lethal recessive alleles? |
Lethal dominant alleles are harmful whether they are carried in homozygous or heterozygous form, so there is always strong selection against these alleles. |
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Which of Mendel's laws have their physical basis in the following phases of meiosis: (a) orientation of homologous chromosomes pairs in metaphase I; (b) the separation of homologs in anaphase I? |
(a) the law of independent assortment; (b) the law of segregation |
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Explain why most eukaryotic genes are longer than the mRNA that leaves the nucleus. |
These genes have introns (which are noncoding sequences of nucleotides that are spliced out of the initial RNA transcript to produce mRNA) |
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What is a silent mutation?
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a mutation in a gene that changes a codon to one that codes for the same amino acid as the original codon. The amino acid sequence of the resulting polypeptide is technically unchanged. |
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What is a missense mutation? |
A change in the nucleotide sequence of a gene that alters the amino acid sequence of the resulting polypeptide. In a missense mutation, a codon is changed from encoding one amino acid to encoding a different amino acid |
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What is a nonsense mutation? |
changes an amino acid codon to a stop codon. The result will be a prematurely terminated protein, which will not function properly |
