CHAPTER 11 Reading Quiz and Homework

DNA renaturation experiments are useful strategies to estimate the size of an organism's genome. genetic relatedness between two species. proportion of GC content in an organism's genome. number of single nucleotide differences between two species.

genetic relatedness between two species.

Most of the centromere and telomere structures consist of GC repeats heterochromatin kinetochore euchromatin

heterochromatin

The inactive form of chromatin is

heterochromatin

The more darkly-staining form of chromatin is

heterochromatin

Telomeres and centromeres are found in unique-sequence DNA. moderately repetitive DNA.LINEs and SINEs. highly repetitive DNA.

highly repetitive DNA.

The largest and most complex mitochondrial genomes come from what? mice. fruit flies. humans. yeasts. flowering plants.

flowering plants.

The longer arm of the chromosome is called the

q arm

Each sequence is one strand of a double-stranded molecule. Which DNA molecule would have the highest melting temperature? 5′-ATATAATTGCAT-3′ 5′-ATGCGGCCAATA-3′ 5′-GCAGGATCCGCG-3′ 5′-AAAAAAAAAAAA-3′

5′-GCAGGATCCGCG-3′ This molecule consists almost entirely of GC base pairs and would have the highest melting temperature.

How does chromosome compaction differ during metaphase and interphase in eukaryotes? Chromosomes are less compacted in metaphase than in interphase. Maximum chromosome compaction occurs during interphase. Chromosomes are more compacted in metaphase than in interphase. There is no chromosome compaction in interphase.

Chromosomes are more compacted in metaphase than in interphase.

Which statement describes the function of the chromatin conformation of DNA? The condensed DNA in chromatin is transported out of the nucleus. Chromatin allows DNA to interact with replication machinery. DNA is wrapped around histone proteins to regulate gene expression. Single‑stranded DNA can be stored in the nucleus as chromatin.

DNA is wrapped around histone proteins to regulate gene expression.

If DNA structure is described as "beads-on-a-string," a "string" is the

DNA molecule

Which of these is generally NOT true about epigenetic effects? Epigenetic effects are rare and do not affect very many traits. Epigenetic effects are more easily reversed than genetic changes. Epigenetic effects are often influenced by environmental factors.

Epigenetic effects are rare and do not affect very many traits.

Which histone protein is not included in the histone "core" that is often described as the "beads"? H2B H3 H4 H1 H2A

H1

How do interspersed repeated DNA sequences differ from tandemly repeated DNA sequences? Tandemly repeated DNA has been shown to disrupt genes and cause disease in humans, but interspersed repeated DNA is never associated with human disease. The repeats in tandemly repeated DNA are up to several kilobase pairs long, but the repeats in interspersed repeated DNA are up to 100 base pairs long. Interspersed repeated DNA is derived from transposable elements, but tandemly repeated DNA is not. Open reading frames are usually found in interspersed repeated DNA, but not in tandemly repeated DNA

Interspersed repeated DNA is derived from transposable elements, but tandemly repeated DNA is not.

What happens to a chromosome that loses its centromere? The chromosome will shorten each time the cell divides. Special proteins bind to this chromosome, protecting it from degradation. It attaches to a spindle microtubule and moves to the spindle pole. It will not segregate into the nucleus in mitosis and is usually lost.

It will not segregate into the nucleus in mitosis and is usually lost.

What evidence suggests that a gene in the mtDNA is causing a disorder? Males and females are both affected and both likely to pass on the trait. Males do not pass on the trait, but females pass it to offspring at a high frequency. Males are more often affected but do not pass on the trait. The disorder exhibits a high degree of penetrance from generation to generation. The disorder is always present in the offspring of an affected parent.

Males do not pass on the trait, but females pass it to offspring at a high frequency.

Which 2 statements accurately describe the structures or functions of mitochondria. The configuration of mitochondria does not change. Mitochondria have a permeable inner membrane and an impermeable outer membrane. Mitochondria regulate apoptosis. Mitochondria are the sites of aerobic metabolism. Mitochondrial DNA is packaged with histones. Mitochondria are included in the endomembrane system.

Mitochondria regulate apoptosis. Mitochondria are the sites of aerobic metabolism.

When looking at bones why would DNA from the mitochondria be analyzed instead of nuclear DNA. (2 answer choices) Mitcohondrial DNA is circular and is more stable over time. Mitochondrial DNA does not undergo recombination. Mitochondrial DNA is inherited from both parents. Mitochondrial genomes are present in multiple copies in the cells.

Mitochondrial DNA does not undergo recombination. Mitochondrial genomes are present in multiple copies in the cells.

Which statement about cellular DNA in incorrect? Supercoiling of cellular DNA is controlled by topoisomerases. Supercoiling makes the separation of the two strands of DNA easier for replication and transcription. Supercoiling allows cellular DNA to be packed into a small space. Most cellular DNA is positively supercoiled. DNA exists in the cell as very long, tightly packed molecules.

Most cellular DNA is positively supercoiled.

Which 2 statements explain why inhibiting negative supercoiling in bacteria inhibits overall bacterial growth? Negative supercoiling aids in chromosome compaction, which ensures the transmission of chromosomes to daughter cells. Negative supercoiling is necessary for the binding of DnaA to the origin of replication. Negative supercoiling decreases chromosome compaction, which increases DNA synthesis in bacteria. Negative supercoiling results in overwound supercoils that initiate DNA synthesis. Negative supercoiling increases the size of the chromosome, making it easier to replicate.

Negative supercoiling aids in chromosome compaction, which ensures the transmission of chromosomes to daughter cells. Negative supercoiling is necessary for the binding of DnaA to the origin of replication.

Which statement about telomeres is NOT correct? Telomeres allow for the replication of the ends of chromosomes. Telomere sequences usually are the same length on different chromosomes and in different cells within the body. Telomeres serve as end caps that stabilize chromosomes. Telomeres usually consist of short sequences repeated hundreds to thousands of times.

Telomere sequences usually are the same length on different chromosomes and in different cells within the body.

The antibiotics tetracycline and erythromycin inhibit bacterial protein synthesis, but have no effect on proteins encoded by eukaryotic, nuclear genes. Conversely, the antibiotic cycloheximide inhibits protein synthesis of nuclear genes, but has no effect on protein synthesis in bacteria. Select the statement that best describes the effect of a particular antibiotic on protein synthesis. Tetracycline treatment would inhibit translation of nuclear genes, but not translation of mitochondrial genes. Cycloheximide treatment would inhibit expression of mitochondrial genes, but not expression of nuclear genes. Tetracycline treatment would inhibit mitochondrial protein synthesis, but not protein synthesis of nuclear genes. It cannot be determined because two of these antibiotics affect bacteria, and cells with mitochondria are eukaryotic. Erythromycin treatment would inhibit protein synthesis from nuclear genes, but not from mitochondrial genes.

Tetracycline treatment would inhibit mitochondrial protein synthesis, but not protein synthesis of nuclear genes.

Which statement about chromatin organization is NOT true? The default (normal) condition of all chromatin is to be transcriptionally active. Heterochromatin is more highly condensed than euchromatin. Chromatin consists primarily of DNA and histone proteins. Actively transcribed genes are found primarily in euchromatin.

The default (normal) condition of all chromatin is to be transcriptionally active. only a small fraction of the genome is transcribed,

Suppose a chemist develops a new drug that neutralizes the positive charges on the tails of histone proteins. What would be the most likely effect of this new drug on chromatin structure? The histones and DNA would not be tightly associated. The histones and DNA would be tightly associated. It would cause the formation of epigenetic changes. It would cause the formation of chromosome puffs.

The histones and DNA would not be tightly associated.

Which 2 statements about euchromatin and heterochromatin are correct? Euchromatin largely consists of repeated sequences. The majority of transcription takes place on euchromatin. Most genes are present in heterochromatin. Euchromatin undergoes condensation and decondensation throughout the cell cycle. Heterochromatin is less condensed than euchromatin.

The majority of transcription takes place on euchromatin. Euchromatin undergoes condensation and decondensation throughout the cell cycle.

Which of these statements about highly repetitive DNA sequences is incorrect? They tend to be present in hundreds of thousands to millions of copies that repeat and cluster in certain regions of the chromosomes. They are rarely transcribed into RNA molecules. They are sometimes referred to as satellite DNA due to the behavior during centrifugation. They tend to contain protein coding sequences in tandem repeats.

They tend to contain protein coding sequences in tandem repeats.

When looking at two DNA molecules, how do you find out which one has the lower melting temperature?

You look at whihc one has the least percentage of G-C base pairs (since G-C contains 3 hydrogen bonds)

Eukaryotic DNA consists of: unique sequences of DNA. highly repetitive DNA sequences. all of these. moderately repetitive DNA sequences.

all of these.

Histone proteins associate with DNA and compact DNA within the nucleus. organize DNA into separate chromosomes at the beginning of mitosis. enable mitochondrial DNA to replicate with nuclear DNA before mitosis. interact with DNA during interphase to delay mitosis when conditions are unfavorable.

associate with DNA and compact DNA within the nucleus.

What contains grana, mitochondria or chloroplasts

chloroplasts

Which feature is a characteristic of most mitochondrial genomes? mitochondrial genes contained on several different DNA molecules histone proteins circular DNA only a single copy of the genome in each cell

circular DNA

Research shows that the chloroplasts was once a

cyanobacteria

When a solution containing double‑stranded DNA is heated, the hydrogen bonds that hold the two strands can be weakened and eventually broken, separating the strands completely.This process is called denaturation. renaturation. double‑strand break. hybridization.

denaturation.

The less condensed form of chromatin is

euchromatin

True or false: The C value, which indicates the amount of DNA in a haploid genome, always correlates to the complexity of the organism. false true

false

Would you expect a chromosome that has a large amount of repeated DNA sequences to have a high or low density of genes? low; repeated DNA sequences have no function, so there would be no genes present in the chromosome high; the repeated sequences each encode a protein, so there would be many copies of that gene/protein present low; repeated DNA sequences do not typically encode genes, so there would be a low density of genes in the chromosome relative to the repetitive DNA sequences

low; repeated DNA sequences do not typically encode genes, so there would be a low density of genes in the chromosome relative to the repetitive DNA sequences

Some epigenetic effects are caused by differences in DNA _____ during development. ubiquitylation methylation alkylation acetylation

methylation

What contains cristae, mitochondria or chloroplasts

mitochondria

Which 2 organelles contain DNA of their own? mitochondria chloroplasts Golgi apparatus endoplasmic reticulum

mitochondria chloroplasts

A student discovers a small amount of DNA in a test tube but doesn't know its origin. She finds that it has no associated histone proteins and is circular. This DNA is most likely from which genome? human sex chromosomes plant nuclear DNA eukaryotic nuclear DNA mitochondrial DNA

mitochondrial DNA

Mitochondrial DNA typically encodes all of these EXCEPT mitochondrial structural proteins. mitochondrial proteins needed for mitochondrial protein synthesis. transfer RNA. ribosomal RNA.

mitochondrial structural proteins.

When a circular DNA gets underrotated by the action of cellular enzymes, the DNA is said to exhibit negative supercoiling. bubbling. positive supercoiling. relaxed state.

negative supercoiling.

A distinct clump of prokaryotic DNA observed via electron microscopy is referred to as a nucleus. nucleosome. nucleolus. plasmid. nucleoid.

nucleoid.

If DNA structure is described as "beads-on-a-string," a "bead" is a

nucleosome

The shorter arm of the chromosome is called the

p arm

Select the 2 examples of genetic material that are uniparentally inherited in sexually reproducing eukaryotes. endoplasmic reticulum DNA plastid DNA mitochondrial DNA nuclear DNA

plastid DNA mitochondrial DNA

Which 3 of the statements are true of endosymbiotic theory? explains the origin of all organelles found within a eukaryotic cell provides insight about why chloroplasts can survive outside of a eukaryotic cell states that an ancestral eukaryotic cell engulfed a photosynthetic protobacteria explains why chloroplasts contain circular DNA similar to bacteria explains the origin of some eukaryotic organelles, such as mitochondria

states that an ancestral eukaryotic cell engulfed a photosynthetic protobacteria explains why chloroplasts contain circular DNA similar to bacteria explains the origin of some eukaryotic organelles, such as mitochondria

Which term describes the tertiary structural organization of chromosomal DNA that allows the long strand to be packed and fit into the cytoplasm of the cell? centromere base pairing double helix supercoiling telomere

supercoiling

Which function of the centromere in the transmission of genetic information. the swelling of the cell in preparation for division the attachment point for the mitotic spindle the formation of the mitotic spindle the synthesis of ribosomal RNA the duplication of DNA

the attachment point for the mitotic spindle

mtDNA and cpDNA contain rRNA and tRNA genes of their own for their organelle‑specific functions. false true

true