Question

1. in the organization of chromatin, how are nucleosomes related to histones? a. nucleosomes are the basic amino acids that make up histones. b. nucleosomes are repeating subunits of dna and histones. c. histones are the compacted structures seen only during mitosis. d. histones are the transcriptionally active regions of the nucleosome. e. nucleosomes are found only in heterochromatin. 28. what property allows rna molecules to adopt complex shapes despite generally being single - stranded? a. the presence of deoxyribose sugar. b. the lack of phosphodiester bonds. c. their long half - life in the cell. d. their exclusive function as genetic information transmission. e. their ability to fold back on themselves to form double - stranded segments via complementary base pairs. 29. in a healthy cell, free iron concentration rises rapidly in the cytoplasm. to deal with this potentially harmful situation, what immediate translational outcome occurs related to ferritin synthesis? a. irp binds more tightly to the ire. b. irp changes shape and releases from the ire, allowing ferritin translation to begin. c. ferritin protein is immediately marked for destruction by ubiquitin. d. risc complex targets the ferritin mrna for degradation. e. the mrna translation process is blocked by a repressor protein. 30. what type of bond connects two complementary nucleotides? a. hydrogen b. ionic c. peptide d. phosphodiester e. covalent 31. if a dna - dependent rna polymerase is synthesizing rna, what direction is the polymerase moving along the dna? a. 5→3 on the template strand b. 3→5 on the coding strand c. 3→5 on the template strand d. 5→3 on the newly forming rna e. 5→3 on the double helix 32. a human gene is analyzed and found to contain 10 exons and 9 introns. if this gene is subject to alternative splicing, how many related polypeptides can potentially be produced? a. only one, as all human genes must encode a single protein. b. exactly 10, one for each exon. c. two or more related polypeptides. d. zero, because the introns prevent transcription. e. exactly 9, one for each intron. 33. a mutation causes a change in the third nucleotide of a codon (the wobble position). what is the likely result in the final protein sequence? a. a guaranteed change in the amino acid. b. the incorporation of a stop codon. c. a high probability that the same amino acid will be incorporated due to redundancy and wobble flexibility. d. the complete inhibition of transcription. e. the requirement for a new aminoacyl - trna synthetase.

Explanation:

1. Nucleosomes are repeating subunits of chromatin and are composed of DNA wrapped around histone proteins.
2. RNA can fold back on itself via complementary base - pairing to form double - stranded segments and complex shapes despite being single - stranded.
3. When free iron concentration rises, IRP changes shape and releases from the IRE, allowing ferritin translation to begin.
4. Complementary nucleotides are connected by hydrogen bonds.
5. DNA - dependent RNA polymerase moves 3' → 5' on the template strand while synthesizing RNA.
6. Alternative splicing can produce two or more related polypeptides from a gene with multiple exons.
7. A mutation in the wobble position of a codon has a high probability of not changing the incorporated amino acid due to redundancy and wobble flexibility in the genetic code.

Answer:

1. b
2. e
3. b
4. a
5. c
6. c
7. c