Biology Chapter: Chromosomes and Cells

Chromosomes and Their Location

• Chromosomes are found in the nucleus of both eukaryotic and prokaryotic cells.
• Present in all types of cells, except mature gametes which contain half the number.

Composition of Chromosomes

• Each chromosome is composed of DNA and proteins, specifically histones, forming a complex known as chromatin.

Somatic Cells

• Somatic cells contain a full set of chromosomes (diploid), including all body cells except sperm and egg cells.

Importance of Mitosis

• Mitosis is crucial for growth, tissue repair, and asexual reproduction.

Stages of Mitosis

• Interphase: Preparation phase, where DNA is replicated and cell organelles are duplicated.
• Prophase: Chromatin condenses into visible chromosomes, and the nuclear envelope breaks down.
• Metaphase: Chromosomes align at the cell's equatorial plane, known as the metaphase plate.
• Anaphase: Sister chromatids are pulled apart toward opposite poles of the cell.
• Telophase: Chromatids reach the poles, nuclear membranes reform, and the chromosomes begin to de-condense.

Important Events in Each Phase

• Interphase: DNA replication and preparation for division.
• Prophase: Formation of spindle fibers from centrioles.
• Metaphase: Attachment of spindle fibers to centromeres.
• Anaphase: Splitting of centromeres.
• Telophase: Reformation of the nucleus and cytokinesis begins.

Role of Mitosis in Cells

• In plant cells, it contributes to growth and repair, forming new tissues.
• In animal cells, it aids in growth, tissue repair, and regeneration.

Scientific Name for Cell Division

• Cell division is scientifically referred to as cytokinesis.

Biological Significance of Mitosis

• Two significant roles: ensures genetic consistency in daughter cells and facilitates organism growth.
• It plays a fundamental role in tissue regeneration and developmental processes.

Differences in Mitosis: Animal vs. Plant Cells

• Animal cells form a cleavage furrow during cytokinesis, while plant cells form a cell plate.
• Plant cells have a rigid cell wall that influences the process differently compared to the flexible cell membrane in animal cells.

Functions Not Associated with Mitosis

• Mitosis does not involve the production of gametes; that process is called meiosis.

Jelly-like Substance Surrounding the Nucleus

• The jelly-like substance is known as cytoplasm.

Substances Transport Across Membranes

• Substances can be transported via diffusion, osmosis, or active transport.

Heredity Definition

• Heredity is the passing of genetic traits from parents to offspring.

Characteristics of Cells Produced by Mitosis

• Each cell produced by mitosis has the same genetic material as the parent cell.

Thread-like Fluid Structure in Cells

• The thread-like fluid structure is called the cytoskeleton.

Strands Contracting During Cell Division

• The strands of cytoplasm that contract are known as microfilaments.

Structures Disappearing at the Start of Mitosis

• The nuclear envelope and nucleolus disappear at the start of mitosis.

Longest Lasting Structure During Mitosis

• The structure that lasts the longest is the spindle apparatus, which helps segregate chromosomes.

Explore the fascinating world of chromosomes and their critical roles in both eukaryotic and prokaryotic cells. Learn about the structure of chromosomes, their composition, and the distinction between somatic cells and gametes. This quiz will test your understanding of cellular biology.