Cell Structure and Function

Cell Structure and Function

• Cells are the fundamental unit of life, exhibiting diverse structures and functions.
• Prokaryotic cells (bacteria and archaea) lack a nucleus and membrane-bound organelles.
• Eukaryotic cells (animals, plants, fungi, protists) possess a nucleus and membrane-bound organelles facilitating specialization.
• Cell membranes regulate the passage of substances in and out of the cell via selective permeability.
• Cytoplasm comprises the jelly-like substance that fills the cell, housing organelles.
• Nucleus contains the cell's genetic material, DNA, crucial for directing cellular activities.
• Mitochondria are the powerhouse of the cell, generating ATP through cellular respiration.
• Ribosomes are responsible for protein synthesis, translating genetic instructions into proteins.
• Endoplasmic reticulum (ER) assists in protein folding and lipid synthesis.
• Golgi apparatus modifies, sorts, and packages proteins for secretion or use within the cell.
• Lysosomes contain digestive enzymes for breaking down waste materials and cellular debris.
• Vacuoles store water, nutrients, and waste products. Plant cells have a large central vacuole.
• Cytoskeleton provides support and structure for the cell, enabling movement and transport.

Cellular Processes

• Cellular respiration is the process by which cells convert glucose into energy (ATP).
• Photosynthesis is the process in plants and some other organisms to convert light energy into chemical energy in the form of sugars.
• Meiosis is a type of cell division that reduces the chromosome number by half, producing gametes (sex cells).
• Mitosis is a type of cell division that produces two identical daughter cells from one parent cell, crucial for growth and repair.
• Protein synthesis involves transcription (DNA to RNA) and translation (RNA to protein).
• DNA replication is the process of creating an exact copy of the DNA molecule.
• Cell signaling involves communication between cells through a variety of mechanisms using chemical messengers.
• Cell cycle describes the process of cell growth, DNA replication, and division.
• Regulation of cell cycle is essential, preventing uncontrolled growth that leads to cancer.

Biological Organization

• Biological organization describes the hierarchical structure of living things, ranging from atoms to the biosphere.
• Atoms combine to form molecules, which assemble into organelles and then cells.
• Cells form tissues, which combine to create organs.
• Organs form organ systems, such as the digestive or circulatory systems.
• Organ systems work together to form organisms.
• Organisms of the same species form populations, which interact to form communities.
• Communities together with the abiotic environment (nonliving factors) form ecosystems.
• Many ecosystems combine to form the biosphere, the global ecosystem.
• Organisms interact within their environment, exhibiting various relationships, including predator-prey, competition, and symbiosis.

Genetics

• DNA is the hereditary material, carrying the genetic instructions for all living organisms.
• The structure of DNA is a double helix with base pairs.
• RNA is involved in protein synthesis and other cellular processes, often considered a middleman or intermediary between DNA and protein.
• Genes are segments of DNA that code for proteins.
• Mutations are changes in the DNA sequence, which can have various effects on traits.
• Genetic variation is essential for evolution by natural selection.
• Inheritance patterns describe how traits are passed from parents to offspring.
• Mendel's laws of inheritance describe dominant and recessive traits, and how they are passed through generations.
• Chromosomes are thread-like structures containing DNA and proteins.