Question

1. how is transcription controlled?25. true / false mutations always affect an entire chromosome.26. define point mutation.27. define frameshift mutation.28. what are the two types of frameshift mutation? 1. 2.29. define insertion.30. define deletion.31. true / false mutations always affect the phenotype.32. what are three ways that gene mutations can change phenotype?1.2.3.33. what are three ways that gene mutations will not change phenotype?1.2.3.34. t / f mutations that occur in body cells do not affect offspring.35. what are three factors that can cause mutations?1.2.3.

Explanation:

1. Transcription is controlled by regulatory proteins (like transcription factors) that bind to promoter/enhancer regions of DNA, as well as epigenetic modifications (e.g., DNA methylation) and RNA interference, which either promote or block RNA polymerase access to genes.
2. Mutations can be small (e.g., point mutations) that only affect a single nucleotide, not an entire chromosome.
3. A point mutation is a change in a single nucleotide base in DNA.
4. A frameshift mutation is a genetic mutation caused by insertion or deletion of a number of nucleotides that shifts the reading frame of the genetic code.
5. The two main types of frameshift mutations are insertions and deletions.
6. Insertion is a type of mutation where one or more extra nucleotide bases are added to a DNA sequence.
7. Deletion is a type of mutation where one or more nucleotide bases are removed from a DNA sequence.
8. Some mutations are silent (change a nucleotide but not the encoded amino acid) and do not alter the phenotype.

32.

1. A mutation can change the amino acid sequence of a protein, altering its function.
2. A mutation can disrupt a regulatory region, changing gene expression levels.
3. A mutation can create a premature stop codon, truncating a protein.

33.

1. A silent mutation changes a nucleotide but not the encoded amino acid.
2. A mutation occurs in a non-coding region of DNA with no functional role.
3. A mutation results in an amino acid change that does not affect protein structure/function (a neutral mutation).
4. Mutations in body (somatic) cells are not passed to gametes, so they cannot be inherited by offspring.

35.

1. Exposure to mutagens like chemical toxins or radiation.
2. Errors that occur during DNA replication.
3. Spontaneous changes to DNA bases over time (e.g., depurination).

Answer:

1. Transcription is controlled by transcription factors binding to regulatory DNA regions, epigenetic modifications (e.g., DNA methylation), and RNA-based mechanisms that regulate RNA polymerase activity and gene expression.
2. False
3. A point mutation is a change in a single nucleotide base within a DNA sequence.
4. A frameshift mutation is a mutation that shifts the reading frame of the genetic code, caused by insertions or deletions of non-multiples of three nucleotides.
5. 1. Insertion 2. Deletion
6. Insertion is a mutation where one or more extra nucleotide bases are added to a DNA sequence, potentially causing a frameshift.
7. Deletion is a mutation where one or more nucleotide bases are removed from a DNA sequence, potentially causing a frameshift.
8. False
9. 1. Alter protein amino acid sequence 2. Disrupt gene regulatory regions 3. Introduce premature stop codons
10. 1. Silent mutation (no amino acid change) 2. Mutation in non-coding DNA 3. Neutral mutation (no protein function change)
11. True
12. 1. Exposure to mutagens (radiation/chemicals) 2. DNA replication errors 3. Spontaneous DNA base damage