Cell Division and Nucleus Reformation

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Questions and Answers

What is the primary function of nucleoplasm?

Transporting molecules to the nucleus

Formation of ribosomes

Creating energy for cellular processes

Providing structure and shape to the cell (correct)

What is a function of nuclear pores?

To act as selective channels between the cytoplasm and the nucleus (correct)

To provide structural support to the nucleus

To replicate DNA during cell division

To produce ribosomes within the nucleus

What important role do chromatin play during cell division?

They form chromosomes that contain genes (correct)

They allow for cytoplasmic streaming

They transport nutrients throughout the cell

They maintain the shape of the cell's nucleus

Where are glycogen granules predominantly found?

In liver cells Signup and view all the answers

What is the composition of nuclear pore complexes?

Proteins arranged radially with a large central hole Signup and view all the answers

What are microfilaments primarily responsible for in a cell?

Maintaining the cell's shape and resiliency Signup and view all the answers

What determines the number of chromosomes in an organism?

Genetic makeup specific to each species Signup and view all the answers

How do abnormal chromosomes typically affect an organism?

They can result in genetic disorders Signup and view all the answers

What is the primary function of cells in the context of reproduction?

They provide half of the genetic material needed for fertilization. Signup and view all the answers

Which statement correctly describes a characteristic of cell organization?

Cells are the basic unit of organization for all multicellular organisms. Signup and view all the answers

What structures do muscle cells have in abundance to support their function?

Mitochondria for energy production Signup and view all the answers

Which type of cell is specifically adapted for covering the body from external environments?

Skin cells that are flat in shape Signup and view all the answers

What distinguishes a prokaryotic cell from eukaryotic cells?

Prokaryotic cells typically contain plasmids. Signup and view all the answers

What size range do plant and animal cells generally fall into?

10-50 μm Signup and view all the answers

What is a common characteristic of all cells in terms of chemical composition?

They are relatively the same in chemical composition and activity. Signup and view all the answers

What feature of neurons is important for their specific functions?

Their cytoplasmic extensions like axons and dendrites. Signup and view all the answers

What type of plant tissue is primarily responsible for active cell division at the tips of roots and shoots?

Meristematic Tissues Signup and view all the answers

What characteristic defines collenchyma tissue?

Thick-walled cells with uneven thickness Signup and view all the answers

Which type of neuron carries information from the central nervous system to effector organs?

Motor Neuron Signup and view all the answers

What is the primary role of parenchyma tissue in plants?

Photosynthesis and food storage Signup and view all the answers

What type of nervous tissue is mostly found in the brain and spinal cord?

Nervous Tissue Signup and view all the answers

Which layer of cells provides protection and replaces the epidermis in mature plants?

Periderm Signup and view all the answers

What is the function of intercalated discs in cardiac tissue?

Connect adjacent cells for synchronized contractions Signup and view all the answers

Which type of plant tissue is considered the most abundant and is involved in various plant activities?

Parenchyma Signup and view all the answers

What significant event occurs during telophase regarding the nuclear envelope?

It starts to reappear. Signup and view all the answers

What is the composition of each chromosome at the start of anaphase I?

Two sister chromatids. Signup and view all the answers

What occurs during prophase I of meiosis?

Crossing over occurs. Signup and view all the answers

What is formed as a result of cytokinesis?

Two new cells. Signup and view all the answers

During which phase do spindle fibers attach to the kinetochores of chromatids?

Prophase I. Signup and view all the answers

What happens to the chromatin fibers of chromosomes at telophase?

They uncoil and become less dense. Signup and view all the answers

What is the result of crossing over during prophase I?

Genetic material is exchanged between homologous chromosomes. Signup and view all the answers

What describes the homologous pairs of chromosomes during prophase I?

They may contain different alleles for the same genes. Signup and view all the answers

What is the primary function of the plasma membrane in eukaryotic cells?

To regulate the entrance and exit of substances. Signup and view all the answers

Which component of the plasma membrane is responsible for its fluid-like properties?

Phospholipid bilayer. Signup and view all the answers

The term 'mosaic' in the fluid mosaic model refers to which aspect of the plasma membrane?

The arrangement of proteins scattered throughout the lipid bilayer. Signup and view all the answers

Which of the following is NOT a function of the glycoalyx?

Transporting substances through the membrane. Signup and view all the answers

Which scientists are credited with the proposal of the fluid mosaic model?

Garth Nicolson and Jonathan Singer. Signup and view all the answers

What is a major characteristic that distinguishes eukaryotic cells from prokaryotic cells?

Eukaryotic cells have membrane-bound organelles. Signup and view all the answers

Which type of protein is primarily embedded within the phospholipid bilayer?

Integral proteins. Signup and view all the answers

What measurement typically characterizes the diameter of eukaryotic cells?

10-100 micrometers. Signup and view all the answers

Study Notes

Cell Division

Polar spindle fibers elongate, prominent nuclei form at opposite poles during telophase.
Nuclear envelopes reappear derived from the parent cell’s nuclear envelope and endomembrane system.
Nucleolus reestablishes in each cell as chromatin fibers uncoil, leading to two new cells with 46 single-stranded chromosomes.
Cytokinesis occurs during telophase, splitting the cytoplasm of the original cell into two new cells.

Meiosis I

Homologous pairs of chromosomes remain together, characterized by synapsis and crossing over in prophase I.
Spindle fibers attach to kinetochores of chromatids as the nuclear membrane and nucleolus disappear.
Chromosomes become visible and are called dyads, each composed of two sister chromatids joined at centromeres.
In anaphase I, homologous chromosome pairs separate to opposite poles, while sister chromatids remain attached.
Telophase I results in two daughter cells completely divided, containing 46 double-stranded chromosomes (92 chromatids).

Cell Structures and Their Functions

Nucleoplasm: Dense substance inside the nucleus aiding in cell shape and forming cilia and flagella cores.
Nucleolus: Spherical structure responsible for ribosome formation.
Microfilaments: Support cell structure and resiliency against external forces; involved in cytoplasmic streaming.
Nuclear Pores: Selective channels between the cytoplasm and nucleus for molecular transport, arranged radially with a central opening.
Chromatin: Composed of DNA and proteins, forms chromosomes during cell division and carries genetic information.

Glycogen Granules

Abundant in liver cells, play a significant role in glucose metabolism.

Biological Pigments

Found in photosynthetic plant cells, contributing to their ability to capture light energy.

Cell Theory Tenets

Cells are the basic unit of life; all living organisms consist of one or more cells.
Cells are the basic organizational units of life, with variations for specialized functions.
Cells arise from preexisting cells and pass on hereditary materials during division.

Cell Size and Shape

Bacterial cells: 1–10 μm, Plant and animal cells: 10–50 μm.
Neuron/Nerve Cell: Has extensions crucial for function.
Skin Cell: Flat shape, provides coverage and protection.

Cell Types

Eukaryotic Cells: More complex, containing a nucleus and organelles, measuring 10–100 μm.
Prokaryotic Cells: Simpler organization, lacking a true nucleus; small circular plasmids may be present.

Plasma Membrane

Thin layer regulating substance entry and exit, crucial for cell shape and flexibility.
Fluid Mosaic Model describes the dynamic nature of the membrane, with proteins embedded in the lipid bilayer.

Glycocalyx

External cell membrane coating made of glycoproteins and polysaccharides; functions in protection and cell recognition.

Plant Tissue Types

Meristematic Tissue: Actively dividing cells at growth tips, responsible for new cell generation.
Fundamental Tissues: Provide support and strength, essential for plant structure.
- Parenchyma: Most abundant tissue, involved in photosynthesis and storage; spherical and pliable.
- Collenchyma: Thick-walled cells offering structural support; uneven wall thickness assists in flexibility.

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Description

This quiz covers the process of cell division, focusing on the roles of polar spindle fibers and the reformation of nuclear envelopes. It examines the transition from chromatin to chromosomes and the significance of nucleolus reappearance. Test your understanding of these key cellular processes.