Genetics Chapter 11 Flashcards

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Questions and Answers

Classify each feature as describing prokaryotic DNA structure or eukaryotic DNA structure.

DNA is circular = Prokaryotic DNA structure DNA is linear = Eukaryotic DNA structure Condensed only by DNA supercoiling = Prokaryotic DNA structure Condensed around histone proteins = Eukaryotic DNA structure Arranged in a single looped structure = Prokaryotic DNA structure Arranged in multiple chromosomes = Eukaryotic DNA structure Does not have telomere region = Prokaryotic DNA structure Has repeating telomere region = Eukaryotic DNA structure

In a circular bacterial chromosome, the structure of DNA is a _ double-helix. If DNA was twisted in the _ direction, it becomes overwound.

right-handed ; right-handed

Overwinding results in _ supercoiling. If DNA is twisted in the _ direction, it becomes underwound.

positive ; left-handed

Underwinding results in _ supercoiling. One effect of _ supercoiling in bacterial chromosomes is to promote separation of the two strands of DNA in the double helix.

negative ; negative Signup and view all the answers

Why does inhibiting negative supercoiling in bacteria inhibit overall bacterial growth?

Negative supercoiling aids in DNA synthesis by making separation of the DNA strands possible and aids in chromosome compaction. Signup and view all the answers

Classify each feature as describing euchromatin, heterochromatin, or both.

Is loosely packed = Euchromatin Has a high level of transcription = Euchromatin Is found in prokaryotes = Euchromatin Is the major state of most genes = Euchromatin Is tightly packed = Heterochromatin Has a low level of transcription = Heterochromatin Is the major state of the inactive X chromosome = Heterochromatin Is a state of DNA organization = Both Signup and view all the answers

Classify each description as applying to either heterochromatin or euchromatin.

The denser form of chromatin = Heterochromatin The form chromatin takes most often when transcription is not occurring = Heterochromatin The looser form of chromatin = Euchromatin The form chromatin takes most often during transcription = Euchromatin Signup and view all the answers

Arrange the features of eukaryotic chromosome packaging in order from the smallest unit to the largest unit.

nucleotide, nucleosome, coiled fiber, chromosome, genome Signup and view all the answers

What do histone proteins do?

Associate with DNA and compact DNA within the nucleus. Signup and view all the answers

What is the function of the chromatin conformation of DNA?

DNA is wrapped around histone proteins to condense and organize DNA. Signup and view all the answers

How does chromosome compaction differ during metaphase and interphase in eukaryotes?

Chromosomes are more compacted in metaphase than in interphase. Signup and view all the answers

What is the function of the centromere in the transmission of genetic information?

The attachment point for sister chromatids. Signup and view all the answers

How do interspersed repeated DNA sequences differ from tandemly repeated DNA sequences?

Interspersed repeated DNA is derived from transposable elements, but tandemly repeated DNA is not. Signup and view all the answers

What is the chromosome puff at position 3C?

A region of active transcription. Signup and view all the answers

What is the definition of uniparental inheritance?

One parent transmits all genetic information to all offspring. Signup and view all the answers

Select the examples of genetic material that are uniparentally inherited in sexually reproducing eukaryotes.

Chloroplast DNA Signup and view all the answers

DNA renaturation experiments are useful strategies to estimate what?

Genetic relatedness between two species. Signup and view all the answers

Select all statements that accurately describe the structures or functions of mitochondria.

Mitochondria are the sites of aerobic metabolism. Signup and view all the answers

Why was mtDNA extracted from the bone samples instead of nuclear DNA?

Mitochondrial genomes are present in multiple copies in the cells and do not undergo recombination. Signup and view all the answers

From which living relatives should mitochondrial DNA be analyzed to verify that the skeletons were those of the royal family?

The mtDNA from the tsar's living relatives of maternal descent should be analyzed. Signup and view all the answers

Which of the statements are true of endosymbiotic theory?

Explains why mitochondria contain their own genetic information Signup and view all the answers

What is the effect of tetracycline on protein synthesis?

Tetracycline treatment would inhibit mitochondrial protein synthesis but not protein synthesis of nuclear genes. Signup and view all the answers

Study Notes

Prokaryotic vs Eukaryotic DNA Structure

Prokaryotic DNA is circular, arranged in a single loop, and lacks telomere regions.
Eukaryotic DNA is linear, organized in multiple chromosomes, and has repeating telomere regions.
Prokaryotic DNA condenses only through supercoiling, while eukaryotic DNA condenses around histone proteins.

Circular Bacterial Chromosomes

DNA in circular bacterial chromosomes has a right-handed double-helix structure.
Overwinding occurs when DNA is twisted right-handedly, leading to positive supercoiling.
Underwinding occurs when twisted left-handedly, resulting in negative supercoiling.
Negative supercoiling facilitates the separation of DNA strands, aiding in replication.

Impact of Nalidixic Acid

Nalidixic acid inhibits DNA gyrase, preventing negative supercoiling.
Negative supercoiling is crucial for DNA synthesis and chromosome compaction, which are vital for bacterial growth and cell division.

Chromatin Types

Euchromatin is loosely packed, transcriptionally active, and represents the major state of most genes.
Heterochromatin is tightly packed, transcriptionally inactive, and is the primary form of the inactive X chromosome.
Both types represent different states of DNA organization.

Chromatin Structure and Function

Heterochromatin appears denser and is prominent when transcription is inactive.
Euchromatin appears looser and is prevalent during transcription to facilitate gene expression.

Eukaryotic Chromosome Packaging

The hierarchical structure of eukaryotic chromosomes progresses from nucleotides to nucleosomes, coiled fibers, chromosomes, and ultimately the genome.

Role of Histone Proteins

Histone proteins associate with DNA, enabling its compaction within the nucleus to fit within a cell.

Chromatin's Role in DNA Organization

Chromatin condenses DNA around histone proteins, facilitating organization and storage within the nucleus.

Chromosome Compaction Phases

Chromosomes are more compact during metaphase compared to interphase, indicating active preparation for cell division.

Centromere Function

The centromere serves as the attachment point for sister chromatids during cell division.

Repeated DNA Sequences

Interspersed repeated DNA originates from transposable elements, while tandemly repeated DNA does not fall under this category.

Chromosome Puff Indication

The puff at position 3C on the X chromosome signifies a region of active transcription necessary for synthesizing specific proteins.

Uniparental Inheritance Definition

Uniparental inheritance involves one parent transmitting all genetic information to the offspring.

Uniparentally Inherited Genetic Material

Mitochondrial DNA and chloroplast DNA serve as examples of genetic material that are exclusively inherited from one parent.

Estimating Genetic Relatedness

DNA renaturation experiments help estimate the genetic relatedness between different species.

Mitochondrial Functions

Mitochondria play critical roles in regulating apoptosis and are essential for aerobic metabolism.

Importance of Mitochondrial DNA in Identification

Mitochondrial DNA, analyzed via PCR, is used to verify identities due to its abundance and lack of recombination compared to nuclear DNA.

Maternal Descent for mtDNA Analysis

Mitochondrial DNA from living relatives of the tsar's family, particularly from maternal lines, is crucial for confirming genetic lineage.

Endosymbiotic Theory Highlights

This theory explains the origin of key eukaryotic organelles, including mitochondria and chloroplasts.
It posits that ancestral eukaryotic cells engulfed photosynthetic proteobacteria, resulting in organelles that retain their own genetic material.

Antibiotics and Protein Synthesis

Tetracycline inhibits mitochondrial protein synthesis while leaving nuclear gene protein synthesis unaffected.
Cycloheximide exclusively targets nuclear gene protein synthesis without impacting bacterial processes.

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Description

This quiz focuses on the structural differences between prokaryotic and eukaryotic DNA as presented in Chapter 11 of the Genetics textbook by Strickland. You'll classify important features and understand the unique aspects of DNA organization in each type of organism.