Q: Which equation best represents the compaction of DNA in a nucleosome core particle?

$$\text{Nucleosome core particle} = 8 \text{ histone molecules} + 146 \text{ base pairs of DNA}$$

Question 1

Which of the following best describes the structural organization of viral chromosomes compared to bacterial and eukaryotic chromosomes?

Accepted Answer

Viral chromosomes are single nucleic acid molecules, largely devoid of associated proteins, and can be either DNA or RNA.

Question 2

Which feature distinguishes polytene chromosomes from typical eukaryotic chromosomes?

Accepted Answer

Polytene chromosomes represent paired homologs that undergo many rounds of replication without strand separation or cytoplasmic division.

Question 3

Which of the following statements about mitochondrial DNA (mtDNA) is correct?

Accepted Answer

mtDNA is circular, double-stranded, and lacks introns and gene repetition.

Question 4

What is the primary function of histones in eukaryotic chromatin?

Accepted Answer

Histones are positively charged proteins that facilitate DNA packaging by forming nucleosomes.

Question 5

Which equation best represents the compaction of DNA in a nucleosome core particle?

Accepted Answer

$$	ext{Nucleosome core particle} = 8 	ext{ histone molecules} + 146 	ext{ base pairs of DNA}$$

Question 6

Which of the following is a consequence of chromatin remodeling in eukaryotic cells?

Accepted Answer

Chromatin remodeling allows for relaxation of compact chromatin structure, enabling DNA–protein interactions necessary for replication and gene expression.

Question 7

Which of the following statements about chloroplast DNA (cpDNA) is correct?

Accepted Answer

cpDNA is circular, double-stranded, free of associated proteins, and contains both introns and duplications.

Question 8

A scientist observes a chromosome with extensive DNA looping in the oocyte of a vertebrate. Which chromosome type is most likely being observed?

Accepted Answer

Lampbrush chromosome

Question 9

Which proteins are primarily responsible for folding and bending bacterial DNA to create coils for compaction?

Accepted Answer

HU and H-NS (Histone-like Nucleoid Structuring Proteins)

Question 10

During which stage of the cell cycle is chromatin dispersed throughout the nucleus and replicated?

Accepted Answer

Interphase

Question 11

Which of the following best explains the evolutionary origin of mitochondrial and chloroplast DNA?

Accepted Answer

They share similarities to DNA found in viruses and bacteria, supporting the endosymbiotic theory.

Question 12

Which of the following is a visible manifestation of high-level gene activity in polytene chromosomes?

Accepted Answer

Puff regions

Question 13

Which histone types occur as tetramers in the nucleosome core particle?

Accepted Answer

H2A, H2B, H3, and H4

Question 14

A mutation disrupts the unstructured histone tails in nucleosomes. Which process is most likely to be affected?

Accepted Answer

Chromatin remodeling and regulation of gene expression

Question 15

Which of the following equations correctly represents the relationship between the length of E. coli DNA and the size of the bacterium?

Accepted Answer

$$	ext{Length of E. coli DNA} = 1200 	ext{ \mu m}$$; $$	ext{Size of E. coli} = 2.00 	ext{ \mu m} 	imes 0.50 	ext{ \mu m}$$

Question 16

Which of the following best describes the role of histone tails in nucleosome structure?

Accepted Answer

Histone tails protrude through the minor groove and make connections with adjacent nucleosomes, influencing chromatin structure.

Question 17

Which of the following scenarios best illustrates the importance of chromatin remodeling in a medical context?

Accepted Answer

A patient with a mutation in histone genes exhibits abnormal gene expression, leading to developmental disorders due to impaired chromatin remodeling.

Chromosome Structure and DNA Organization: Study Notes

Guida di studio - Domande di pratica

Study guide - Flashcard