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Questions and Answers
Why did some bacteria survive after coming into contact with the chemical?
Scientists have been able to develop strawberries that resist the harmful effects of frost. Which process best describes how scientists are able to produce these strawberries?
Which statement best summarizes how the first cells may have evolved?
How has natural selection resulted in antibiotic resistance in bacteria?
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What is a codon?
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What determines the sequence of amino acids in a protein?
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How many amino acids could potentially be coded by a sequence of 15 nucleotides in DNA?
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What role do nucleotides play in protein synthesis?
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What happens if a nucleotide is missing in a DNA sequence coding for a protein?
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How many codons are necessary to code for a protein consisting of 6 amino acids?
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Which sequence represents a possible three-codon combination in DNA?
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What is the role of a start codon in protein synthesis?
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How does a frameshift mutation affect the reading of codons?
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Which molecules directly interact with codons during protein synthesis?
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Study Notes
Genetic Variation and Resistance
- A population of bacteria was exposed to a chemical, resulting in most bacteria dying within 24 hours.
- However, a few bacteria survived due to a genetic variation that provided resistance to the chemical.
- This genetic variation was present in the surviving bacteria before exposure to the chemical.
- It did not occur as a result of ingesting and digesting the chemical, mutating into a different species, or changing their DNA sequence.
Genetic Modification in Strawberries
- Scientists have developed strawberries that resist frost damage.
- This achievement is possible through a specific process in genetic modification.
Genetic Engineering
- Genetic engineering is the process used to produce frost-resistant strawberries.
- This process involves the direct manipulation of an organism's genes.
Origin of Life
- The most widely accepted scientific theory is that life arose from non-living matter through a process called abiogenesis.
- Abiogenesis started with the formation of organic molecules from inorganic compounds.
- These organic molecules self-assembled into more complex structures, eventually leading to the formation of the first cells.
Characteristics of Cell Evolution
- The first cells were not eukaryotic, as they are more complex and thought to have evolved later.
- Eukaryotic cells did not form directly from inorganic compounds.
Incorrect Theories
- Organic compounds do not form inorganic compounds.
- Photosynthesis was not involved in the formation of the first cells.
Antibiotic Resistance in Bacteria
- Natural selection has led to antibiotic resistance in bacteria due to existing genetic variation among bacterial populations.
- This variation allows some bacteria to survive and reproduce in the presence of antibiotics.
- Over time, these resistant bacteria multiply, leading to an increase in antibiotic-resistant bacterial populations.
- The resistance is not caused by chemical reactions neutralizing antibiotics or changes in bacterial shape causing mutations.
- Also, an increase in bacterial reproduction does not result in a shortened lifespan.
DNA Codons
- Three consecutive nucleotides in DNA are called a codon.
- A codon codes for one amino acid.
- This is the significance of three consecutive nucleotides in DNA.
Codons and Amino Acids
- A codon is a sequence of three consecutive nucleotides in DNA.
- A codon codes for one amino acid.
- A single codon does not code for three amino acids.
- A codon does not code for one complete protein.
- A codon does not code for three complete proteins.
- Amino acids are coded by codons in DNA.
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Description
Learn about genetic variation in bacteria that confers resistance to certain chemicals, and how this trait was present in the surviving bacteria before exposure.
