Chromatin and Chromosomes Quiz
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Questions and Answers

What is the function of chromatin in the cell nucleus?

  • To allow very long DNA molecules to fit into the cell nucleus (correct)
  • To condense further and form microscopically visible chromosomes
  • To replicate and divide during cellular division
  • To ensure the genetic diversity and survival of progeny

What are the major structures involved in DNA compaction?

  • Nucleotide, DNA pyrophosphorylase, nucleoside triphosphatase
  • Centromere, chromatids, histones
  • Histones, RNA-polymerase, DNA- polymerase
  • The 30 nm fibre, the metaphase chromosome, the 10 nm 'beads-on-a-string' fibre (correct)

Which type of proteins have enzymatic activities?

  • High molecular weight proteins
  • Non-histones or acidic proteins (correct)
  • Basic proteins
  • Low molecular weight proteins

In which type of cells are multiple large linear chromosomes contained in the cell's nucleus?

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

What is the difference between duplicated and unduplicated chromosomes?

<p>Duplicated chromosomes contain two identical copies joined by a centromere (A)</p> Signup and view all the answers

What are the proteins with enzymatic activities in chromosomes?

<p>Non-histones (A)</p> Signup and view all the answers

In which cell cycle phase do chromosomes condense further to form microscopically visible structures?

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

Which type of chromosomes contain two identical copies joined by a centromere?

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

What is the function of chromatin during cell division?

<p>To form microscopically visible chromosomes (A)</p> Signup and view all the answers

What are the major structures involved in DNA compaction?

<p>Histones and nucleosomes (C)</p> Signup and view all the answers

Describe the role of chromatin in the cell nucleus.

<p>Chromatin allows very long DNA molecules to fit into the cell nucleus and condenses further during cell division to form microscopically visible chromosomes.</p> Signup and view all the answers

Explain the difference between duplicated and unduplicated chromosomes.

<p>Unduplicated chromosomes are single double helixes, whereas duplicated chromosomes contain two identical copies (called chromatids or sister chromatids) joined by a centromere.</p> Signup and view all the answers

What are the two types of proteins found in chromosomes and what are their functions?

<p>i) Low molecular weight proteins: histones or basic proteins; ii) High molecular weight proteins or non-histones or acidic protein. The acidic proteins have enzymatic activities.</p> Signup and view all the answers

List the major structures involved in DNA compaction.

<p>The major structures in DNA compaction include DNA, the nucleosome, the 10 nm 'beads-on-a-string' fibre, the 30 nm fibre, and the metaphase chromosome.</p> Signup and view all the answers

In which type of cells are multiple large linear chromosomes contained in the cell's nucleus?

<p>Eukaryotes, such as those found in plants, fungi, and animals, possess multiple large linear chromosomes contained in the cell's nucleus.</p> Signup and view all the answers

Flashcards

What is chromatin?

Chromatin is the material that makes up chromosomes in eukaryotic cells. It's basically DNA tightly wound around proteins called histones.

What is the role of chromatin in the nucleus?

The main function of chromatin is to condense and organize DNA, making it fit inside the cell nucleus. This process is essential for cell division.

What are histones?

Histones are positively charged proteins that bind to negatively charged DNA molecules. They help package DNA into tight structures called nucleosomes.

What is a nucleosome?

A nucleosome is the basic unit of chromatin. It consists of DNA wrapped around a core of eight histone proteins.

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What is the 'beads-on-a-string' fiber?

The 10 nm 'beads-on-a-string' fiber is a structure formed by chains of nucleosomes linked by stretches of linker DNA.

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What is the 30 nm fiber?

The 30 nm fiber is a more compact structure formed from the 10 nm fiber. It's like a coil of the 'beads-on-a-string' fiber.

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What is a metaphase chromosome?

The metaphase chromosome is the most condensed form of chromatin. It's visible under a microscope during cell division.

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What are duplicated chromosomes?

Duplicated chromosomes have two identical copies of DNA, called sister chromatids, joined at the centromere. Each copy is a complete chromosome.

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What are unduplicated chromosomes?

Unduplicated chromosomes contain only a single DNA molecule. They are the result of DNA replication and are ready to be duplicated into sister chromatids.

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What are non-histone proteins?

Non-histone proteins, also known as acidic proteins, are involved in a variety of functions in chromosomes. They have enzymatic activities, helping regulate DNA replication, repair and gene expression.

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How are duplicated chromosomes formed?

The process of DNA replication produces two identical copies of DNA, which are held together by a centromere to form a duplicated chromosome. This happens during the S-phase of the cell cycle.

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Why do chromosomes condense during cell division?

Chromosomes condense further during the metaphase stage of cell division, making them visible under a microscope. This allows for equal distribution of genetic material to daughter cells.

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What are eukaryotic cells?

Eukaryotic cells are complex cells with a nucleus that contains multiple linear chromosomes. This organization helps regulate gene expression and ensures proper cell division.

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What are prokaryotic cells?

Prokaryotic cells are simpler cells without a nucleus. Their DNA is found in a single, circular chromosome located in the cytoplasm.

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Study Notes

Chromatin and DNA Compaction

  • Chromatin is a complex of DNA, histone proteins, and other non-histone proteins that form a chromosome
  • The major structures involved in DNA compaction are chromatin, nucleosomes, chromonema, and chromonemata
  • Chromatin plays a crucial role in the cell nucleus by allowing for the compaction of a large amount of DNA into a small space

Chromosome Structure

  • Chromosomes contain two main types of proteins: histones and non-histone proteins
  • Histones (H1, H2A, H2B, H3, H4) have a structural role, while non-histone proteins have enzymatic activities
  • Duplicated chromosomes have two identical copies of DNA, joined by a centromere, whereas unduplicated chromosomes have a single copy of DNA

Cell Cycle and Chromosome Condensation

  • During the prophase stage of the cell cycle, chromosomes condense further to form microscopically visible structures
  • This condensation is essential for proper Separation of chromosomes during cell division

Cell Types and Chromosomes

  • In eukaryotic cells, multiple large linear chromosomes are contained in the cell's nucleus
  • In these cells, chromatin plays a crucial role in packaging the DNA into chromatin fibers, allowing for the compaction of the genome

Chromatin Functions

  • Chromatin has two main functions during cell division: it allows for the compaction of DNA and enables the equal distribution of genetic material between daughter cells

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Test your knowledge about chromatin, chromosomes, and their roles in cell division and genetic diversity. Explore the structure and behavior of chromosomes during the cell cycle.

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