Cell Structure and Function

Cell Structure and Function

• Cells are the fundamental units of life, exhibiting diverse shapes, sizes, and functions.
• A typical cell encompasses a plasma membrane, cytoplasm, and a nucleus, though structures vary.
• Prokaryotic cells, like bacteria, lack a nucleus and membrane-bound organelles.
• Eukaryotic cells, including animal and plant cells, possess a nucleus and various organelles.
• The plasma membrane regulates substance passage, maintaining cellular homeostasis.
• Cytoplasm is the cell's internal, semi-fluid medium, housing organelles.
• The nucleus contains the cell's genetic material (DNA), directing cellular activities.
• Organelles like mitochondria, ribosomes, and the endoplasmic reticulum execute specialized functions.
• Mitochondria facilitate cellular respiration, producing energy (ATP) for the cell.
• Ribosomes synthesize proteins vital for cellular processes.
• The endoplasmic reticulum supports protein synthesis and lipid metabolism.
• The Golgi apparatus modifies, sorts, and packages proteins for secretion.

Cellular Processes

• Cellular respiration converts glucose into ATP, the cell's primary energy source.
• Photosynthesis, employed by plants and autotrophs, transforms light energy into glucose.
• Cellular division (mitosis and meiosis) is crucial for growth, repair, and reproduction.
• Mitosis produces two genetically identical daughter cells, essential for growth and repair.
• Meiosis generates gametes (sex cells) with half the number of chromosomes, vital for sexual reproduction.
• DNA replication ensures each daughter cell receives an identical DNA copy.
• Transcription converts DNA into RNA, a prerequisite for protein synthesis.
• Translation synthesizes proteins from RNA.
• Cell signaling enables communication between cells, orchestrating coordinated responses and maintaining homeostasis.
• Apoptosis (programmed cell death) controls development, homeostasis, and waste disposal, protecting against damaged cells.

Genetics

• Heredity transmits traits from parents to offspring.
• Genes, segments of DNA, code for specific traits.
• DNA carries genetic information.
• DNA's structure is a double helix of nucleotides.
• DNA replication ensures accurate duplication of genetic information.
• Mutations alter DNA sequences, potentially affecting protein structure and function.
• The Central Dogma describes genetic information flow: DNA to RNA to protein.
• Genetic variations arise from mutations and other mechanisms.
• Genetic engineering modifies genetic material.

Ecology

• Ecology investigates interactions between organisms and their environment.
• Ecosystems comprise biotic (living) and abiotic (non-living) components.
• Populations are groups of the same species in an area.
• Communities are interacting populations in a defined area.
• Energy flows through ecosystems via food chains and webs.
• Nutrient cycles (e.g., the carbon cycle) are essential for ecosystem health.
• Biomes are large areas with similar climates and vegetation.
• Biodiversity encompasses life's variety at all levels, from genes to ecosystems.
• Human activities significantly influence ecosystems.