Question 1

Suppose a cell lacks functional Shugoshin.What is the predicted effect on cohesin?
A)Cohesin will be cleaved prior to metaphase in mitosis.
B)Cohesin will not be cleaved during mitosis or meiosis.
C)Cohesin at the centromeres of sister chromatids will be cleaved during meiosis I.
D)Cohesin on the arms of sister chromatids will be cleaved during meiosis II.
E)Cohesin will be cleaved normally during mitosis and meiosis I.

Accepted Answer

Shugoshin protects cohesin at the centromeres during meiosis I. Without functional Shugoshin, cohesin at the centromeres will be cleaved during meiosis I, leading to premature separation of sister chromatids.

Question 2

The technique of preparing mitotic chromosomes involves a staining procedure using Giemsa stain.In this procedure, chromosomes are first ________ and then exposed to stain, producing ________ in a standard human karyotype.
A)heated; hundreds of reproducible bands
B)heated; thousands of reproducible bands
C)fragmented; hundreds of reproducible bands
D)fragmented; hundreds of variable bands

Accepted Answer

The technique involves heating chromosomes before staining with Giemsa, which results in hundreds of reproducible bands in a standard human karyotype. This banding pattern is crucial for identifying chromosomal abnormalities.

Question 3

The creation of yeast artificial chromosomes preceded the production of the first yeast
A)synthetic chromosome that includes sequences from the human genome.
B)synthetic chromosome that lacks about 50,000 bp from the normal yeast third chromosome.
C)essential chromosome that combines the 1000 essential yeast genes into one chromosome.
D)circular chromosome that does not require telomere sequences.

Accepted Answer

Yeast artificial chromosomes (YACs) were developed before the creation of synthetic chromosomes, including the one that lacks about 50,000 bp from the normal yeast third chromosome.

Question 4

A barrier element between a gene and heterochromatin would prevent that gene from being transcriptionally silenced by heterochromatin spreading.

Accepted Answer

Barrier elements are DNA sequences that block the spread of heterochromatin into adjacent euchromatin regions, thereby preventing the transcriptional silencing of genes located near heterochromatin.

Question 5

What is the structure of telomeres?
A)short, repetitive DNA sequences found at the ends of linear eukaryotic chromosomes
B)long, repetitive DNA sequences found at the ends of linear eukaryotic chromosomes
C)short, repetitive DNA sequences found at the ends of linear prokaryotic chromosomes
D)long, unique DNA sequences found at the ends of linear eukaryotic chromosomes

Accepted Answer

Telomeres are short, repetitive DNA sequences located at the ends of linear eukaryotic chromosomes, which protect the chromosome ends from deterioration or from fusion with neighboring chromosomes.

Question 6

Methylated histone tail amino acids are associated with chromatin that is
A)either open or closed.
B)open only.
C)closed only.
D)newly replicated.
E)about to replicate.

Accepted Answer

Methylated histone tails can be associated with either transcriptionally active (open) or inactive (closed) chromatin, depending on the specific amino acid that is methylated and the number of methyl groups added.

Question 7

Kinetochores include motor proteins that exert pulling forces on spindle microtubules.

Accepted Answer

Kinetochores attach chromosomes to spindle microtubules during cell division and include motor proteins that exert pulling forces, facilitating chromosome movement towards the spindle poles.

Question 8

What is true about new nucleosome formation during DNA replication?
A)Nucleosomes will be composed of different combinations of H3/H4 tetramers and H2A/H2B that are either newly synthesized or were from previous histone octamers.
B)Nucleosomes will be composed of different combinations of H3/H2A tetramers and H4/H2B that are either newly synthesized or were from previous histone octamers.
C)One DNA strand will have newly synthesized octamers and the other will have previously synthesized octamers.
D)Nucleosomes will be composed of different combinations of H2A/H2B/H3/H4 tetramers that are either newly synthesized or were from previous histone octamers.

Accepted Answer

During DNA replication, nucleosomes are disassembled ahead of the replication fork and then reassembled on the newly synthesized DNA. The new nucleosomes are composed of a mix of old and new histones. Specifically, the H3/H4 tetramers are partially retained from the original nucleosome and can associate with newly synthesized H2A/H2B dimers to form new nucleosomes. This ensures the preservation of some of the original histone modifications and thus some of the epigenetic information.

Question 9

Acetylated histone tail lysines are associated with chromatin that is
A)open.
B)closed.
C)transcriptionally inactive.
D)newly replicated.
E)about to replicate.

Accepted Answer

Acetylated histone tail lysines are associated with open chromatin, which is typically transcriptionally active. This modification reduces the positive charge on lysines, weakening the interaction between histones and DNA, thereby making the DNA more accessible to transcription machinery.

Question 10

The position of a gene located within a light G band on the short arm of chromosome 5 could be designated as
A)5p13-pter.
B)5p13-qter.
C)p513.
D)5q13-qter.
E)q513.

Accepted Answer

The correct designation for a gene located within a light G band on the short arm of chromosome 5 is "5p13-pter." This notation indicates the gene is on the short arm (p) of chromosome 5, in the specific region labeled 13, extending towards the telomere (pter) of the short arm. The "p" denotes the short arm of the chromosome, "q" would denote the long arm, and "ter" refers to the terminal end of the arm.

Question 11

Which statement correctly describes the similarity of centromeres in different organisms?
A)Both yeast and plant centromeres have two 10-to-15 bp conserved elements.
B)Yeast centromeres have fewer satellite DNA repeats than do human centromeres.
C)Both human and plant centromeres are composed of repeated satellite DNA sequences.
D)Yeast centromeres have fewer satellite DNA repeats than do plant centromeres.

Accepted Answer

Both human and plant centromeres are composed of repeated satellite DNA sequences.

Quiz 12: The Eukaryotic Chromosome

Suppose a cell lacks functional Shugoshin.What is the predicted effect on cohesin?

The technique of preparing mitotic chromosomes involves a staining procedure using Giemsa stain.In this procedure, chromosomes are first and then exposed to stain, producing in a standard human karyotype.

The creation of yeast artificial chromosomes preceded the production of the first yeast

A barrier element between a gene and heterochromatin would prevent that gene from being transcriptionally silenced by heterochromatin spreading.

What is the structure of telomeres?

Methylated histone tail amino acids are associated with chromatin that is

Kinetochores include motor proteins that exert pulling forces on spindle microtubules.

What is true about new nucleosome formation during DNA replication?

Acetylated histone tail lysines are associated with chromatin that is

The position of a gene located within a light G band on the short arm of chromosome 5 could be designated as

Which statement correctly describes the similarity of centromeres in different organisms?