Resumen Science I periodo

Cell Structure and Function

Plant cells possess a cell wall, which is a rigid layer providing protection and support. The cell membrane lies within the wall, regulating substance movement in and out of the cell. The nuclear envelope protects the nucleus, while chromatin contains genetic material that directs cellular functions. Ribosomes, found in the cytoplasm along with various organelles, are crucial for protein production. The endoplasmic reticulum transports proteins and materials, while Golgi bodies process and distribute these proteins. Chloroplasts, exclusive to plant cells, capture sunlight for food production. Vacuoles store various materials, and lysosomes contain chemicals for breaking down substances.

Cell Theory and Types of Cells

Cell theory posits that all living things are composed of cells, cells are the basic unit of life, and all cells arise from pre-existing cells. Bacterial cells are smaller than plant and animal cells, containing ribosomes but lacking a nucleus, placing genetic material in the cytoplasm.

Cell Membrane and Transport

The cell membrane is selectively permeable, allowing specific substances to pass while blocking others. Key processes include diffusion (movement from higher to lower concentration), osmosis (movement of water across a membrane), and active transport (movement requiring energy, often against concentration gradients).

Photosynthesis and Cellular Respiration

Photosynthesis occurs in chloroplasts, converting carbon dioxide and water into glucose and oxygen using sunlight. Respiration breaks down glucose in mitochondria to produce energy, carbon dioxide, and water. Both processes are vital for energy production in cells, with photosynthesis capturing energy and respiration releasing it.

Cell Cycle

The cell cycle includes interphase (cell growth and DNA replication) and mitosis (division of the nucleus), culminating in cytokinesis (division of the cytoplasm), producing two daughter cells. Mitosis consists of four phases: prophase, metaphase, anaphase, and telophase.

Genetics

Genetics is the study of heredity, with traits passed from parents to offspring through genes. Traits can be dominant (expressed when present) or recessive (masked by dominant traits). Probability can predict trait inheritance, often visualized using Punnett squares, which illustrate possible genetic combinations for traits.