Cell Biology: Metabolism and Nucleus

Metabolism

• Metabolism occurs in organelles, including the nucleus and chloroplast.

Nucleus

• Largest organelle visible in a cell, located in the cytoplasm.
• Specialized cells like red blood cells and xylem vessels lack a nucleus.
• Regulates metabolic reactions and contains genes within chromosomes.
• Genes, composed of Deoxyribose Nucleic Acid (DNA), dictate protein production and inheritance of physical traits.

Cell Wall

• Non-living structure surrounding the cell membrane in plants.
• Composed of cellulose, a carbohydrate that is freely permeable to salts and water.
• Maintains plant shape by becoming turgid, which results from water absorption creating internal pressure.

Cells

• Basic structural and functional unit of organisms, with 10-100 million cells in the human body.
• Shared components in plant and animal cells include cytoplasm, nucleus, cell membrane, ribosomes, and mitochondria.

Mitochondria

• Known as the powerhouse of the cell, responsible for energy production during respiration.

Ribosome

• Site of protein synthesis, essential for cellular function.

Cell Membrane

• Thin surface layer made of proteins and lipids, not visible under regular microscopes.
• Partially permeable, controlling substance movement in and out of the cell, while retaining cell contents.

Cytoplasm

• Jelly-like substance making up most of the cell, involved in numerous chemical reactions.

Blood Cells

• Most common cells in the human body derived from bone marrow.
• Mature blood cells lose their nucleus, acquiring a biconcave disk shape for enhanced oxygen exchange.
• Flexible structure facilitates movement through narrow blood capillaries.

Xylem Vessels

• Composed of dead, hollow cells transporting water and ions from roots to leaves.
• Mature cells elongate and lose walls between cells, with lignin providing structural support.

Tissue and Organ Formation

• Similar cells group to form tissues; similar tissues combine to create organs, which work in concert within organ systems to sustain life.

Bacteria

• Unicellular organisms that are simpler and smaller than plant and animal cells.

Bacterial Cell Wall

• Comprised of peptidoglycan, a protein distinct from cellulose and chitin, providing structural support.

Capsule

• Protective slime layer around bacteria, preventing desiccation.

Cytoplasm in Bacteria

• Contains minimal organelles and lacks a nucleus; chromosomes exist as a loose single strand.

Plasmids

• Circular DNA rings carrying genes, utilized in genetic engineering.

Flagellum

• A tail-like structure enabling bacteria to swim by moving in a propeller-like motion.

Sap Vacuole

• Large, permanent cytoplasmic space in mature plants, containing a sugary solution that acts as a solvent.

Chloroplast

• Large organelle in green plant parts, containing chlorophyll for photosynthesis.

Differences Between Plant and Animal Cells

• Animal cells are smaller and contain centrioles; they lack a rigid cell wall, allowing for flexible shape.

Specialized Cells

• Root hair cells facilitate water absorption by increasing surface area through their elongated shape, optimizing osmosis and transport of ions.

Binary Fission

• Reproductive process in prokaryotic organisms (like bacteria) where a single cell divides into two after replicating genetic material.
• Resulting cells possess similar genetic material, with plasmids distributed randomly during division.
• Bacteria can divide every 20 minutes given favorable conditions of warmth, moisture, and nutrient availability.

Explore the fascinating world of cell biology with this quiz on metabolism and the structure of the nucleus. Understand the roles of organelles, chromosomes, and the significance of DNA in controlling metabolic processes within cells. Test your knowledge and learn about cell functions!