DNA Organization in Chromosomes

<p>Glycosylation (D)</p> Signup and view all the answers

<p>It usually decreases gene activity, especially in CpG islands. (D)</p> Signup and view all the answers

<p>Euchromatin is uncoiled and transcriptionally active, while heterochromatin is condensed and transcriptionally inactive. (A)</p> Signup and view all the answers

<p>A region of DNA that contains centromeres (D)</p> Signup and view all the answers

<p>Chromatin remodeling allows for the controlled access of proteins to DNA, influencing gene expression. (C)</p> Signup and view all the answers

<p>147 base pairs (C)</p> Signup and view all the answers

<p>H1 (A)</p> Signup and view all the answers

<p>1400 nm (B)</p> Signup and view all the answers

<p>Centriole (A)</p> Signup and view all the answers

<p>500 to 1 (C)</p> Signup and view all the answers

<p>It decreases the length by about one-third (D)</p> Signup and view all the answers

<p>Formation of sister chromatids (B)</p> Signup and view all the answers

<p>To package DNA into nucleosomes (B)</p> Signup and view all the answers

<p>C-banding (D)</p> Signup and view all the answers

<p>Differentiating chromosomes based on banding patterns (B)</p> Signup and view all the answers

<p>The influence of heterochromatin on the transcription of nearby genes (A)</p> Signup and view all the answers

<p>A condensed, inactive X chromosome found in female mammals (A)</p> Signup and view all the answers

<p>Actively transcribed (C)</p> Signup and view all the answers

<p>G-banding reveals banding patterns along the entire chromosome, while C-banding only stains specific heterochromatic regions (D)</p> Signup and view all the answers

<p>Identifying the cause of a viral infection (D)</p> Signup and view all the answers

<p>It allows for the identification of individual chromosomes based on their unique banding patterns (C), It provides a universal language for describing the structure of chromosomes (E)</p> Signup and view all the answers

<p>Viruses have smaller, more efficient genomes, while eukaryotes have larger, more complex genomes. (A)</p> Signup and view all the answers

<p>Viral chromosomes are simpler than bacterial chromosomes due to their smaller size and lack of associated proteins. (C)</p> Signup and view all the answers

<p>All of the above. (D)</p> Signup and view all the answers

<p>These techniques identify and classify different chromosomes based on their banding patterns. (B)</p> Signup and view all the answers

<p>Eukaryotic genomes are organized into complex structures, including histone proteins and chromatin fibers. (A)</p> Signup and view all the answers

<p>Less condensed chromatin structures, like euchromatin, promote gene transcription by making DNA more accessible. (A)</p> Signup and view all the answers

<p>Epigenetic modifications like DNA methylation and histone acetylation can alter gene expression by affecting chromatin accessibility. (B)</p> Signup and view all the answers

<p>The eukaryotic genome is more complex than bacterial or viral genomes, with a large portion being noncoding. (B)</p> Signup and view all the answers

<p>Topoisomerases remove supercoils generated during replication and transcription, preventing DNA tangling. (B)</p> Signup and view all the answers

<p>The larger size of eukaryotic genomes. (A)</p> Signup and view all the answers

<p>Chromatin consists of repeating structural units called nucleosomes, which are tightly packed together to condense DNA. (C)</p> Signup and view all the answers

<p>They enable histones to interact electrostatically with the negatively charged phosphate groups of DNA. (D)</p> Signup and view all the answers

<p>Removal of histones disrupts the regular diffraction pattern of chromatin, indicating a loss of its organized structure. (A)</p> Signup and view all the answers

<p>10,000 times (D)</p> Signup and view all the answers

<p>It is found only during mitosis and meiosis. (D)</p> Signup and view all the answers

<p>Topoisomerases remove supercoils from DNA. (D)</p> Signup and view all the answers

<p>The presence of supercoiling (C)</p> Signup and view all the answers

<p>Forms a circle upon infecting a host cell (D)</p> Signup and view all the answers

<p>They produce supercoils in circular DNA (B)</p> Signup and view all the answers

<p>It allows for the packaging of long DNA molecules into small volumes. (A)</p> Signup and view all the answers

<p>It is highly supercoiled due to underwinding of the DNA helix. (D)</p> Signup and view all the answers

<p>Circular DNA allows for the efficient packaging of genetic material into small volumes. (A)</p> Signup and view all the answers

<p>Through high-speed centrifugation, which separated DNA based on density. (A)</p> Signup and view all the answers

<p>Topoisomerase II (B)</p> Signup and view all the answers

Eukaryotic DNA is organized into nucleosomes, coiling into chromatin and chromosomes during the cell cycle.

Chromatin is a complex of DNA and proteins that condense to form chromosomes during cell division.

Euchromatin is less condensed and active in transcription; heterochromatin is more condensed and inactive.

Viral DNA can be DNA or RNA and varies in size and structure, often simpler than bacterial DNA.

Bacterial chromosomes are typically circular, smaller, and lack associated proteins, containing less genetic information.

The chromatin structure model explains DNA organization in a hierarchical manner, influencing replication and transcription.

Gene transcription can be affected by epigenetic marks like DNA methylation and histone acetylation.

C-banding and G-banding are techniques for staining chromosomes; G-banding helps with human chromosome identification.

Can be DNA or RNA, single/double-stranded, linear/circular.

DNA molecules that form closed loops, often supercoiled.

The process of DNA twisting to increase compactness.

Enzymes that modify the supercoiling of DNA by cutting and resealing strands.

Underwound DNA that aids in compaction and stability.

A circular DNA molecule approximately 1.2 mm long.

Region in bacteria where the chromosome is compacted.

Type I cuts one strand, Type II cuts both strands of DNA.

Tight coils of DNA formed due to twisting and tension, important in DNA replication and transcription.

Structural units of chromatin consisting of DNA wrapped around histone proteins.

Process where chromatin becomes highly condensed to form chromosomes during mitosis.

Positively charged proteins that help organize and compact DNA into chromatin.

Eukaryotic DNA is more complex, longer, and associated with more proteins than prokaryotic DNA.

The total DNA in a single human nucleus can extend almost 2 meters.

The process by which chromatin changes structure for protein-DNA interactions and gene expression.

A nucleosome consists of 147 base pairs of DNA wrapped around four pairs of histone proteins.

A modification where acetyl groups are added to histones, neutralizing positive charges and promoting gene activation.

High acetylation levels indicate active genes, while low levels are seen in inactive regions like Barr bodies.

Chemical alterations of histone tails, such as methylation and phosphorylation, that impact gene expression.

The addition of a methyl group to cytosine in DNA, often linked to reduced gene activity, especially in CpG islands.

Condensed, genetically inactive chromatin that replicates later in the cell cycle, includes telomeres and centromeres.

A protein complex made of eight histone proteins in a nucleosome.

The DNA segment that connects nucleosomes and is associated with histone H1.

A higher-order structure formed by nucleosomes coiling and stacking.

A Barr body is an inactivated X chromosome in female mammals, appearing as a condensed heterochromatic structure.

The position effect describes how a gene's expression is influenced by its location relative to neighboring genetic material.

Proteins that help package DNA into nucleosomes, critical for chromatin formation.

C-banding is a chromosome-banding technique involving Giemsa stain to highlight heterochromatic regions, particularly at centromeres.

The size of the human nucleus, approximately 5 to 10 μm.

G-banding is a technique using trypsin digestion followed by Giemsa staining, resulting in distinct banding patterns on chromosomes.

The organizational levels of banding show how chromosomes are structured, allowing identification of specific regions.

Chromosome banding patterns are unique staining variations along chromosomes that allow differentiation among similar chromosomes.

Cytogenetic analysis uses chromosome banding patterns to identify specific chromosomes for genetic studies, especially in humans.