Cell Biology: Structure and Respiration

Cell Structure and Function

• Cells are the basic units of life, exhibiting a complex internal structure and specialized functions.
• Prokaryotic cells (bacteria and archaea) lack a nucleus and membrane-bound organelles.
• Eukaryotic cells (plants, animals, fungi, protists) possess a nucleus and various membrane-bound organelles with specific functions.
• The cell membrane is a selectively permeable barrier, regulating the passage of substances into and out of the cell.
• The cytoplasm is the jelly-like substance filling the cell, containing various organelles.
• The nucleus contains the cell's genetic material (DNA) and controls cellular activities.

Cellular Respiration

• Cellular respiration is the process by which cells break down glucose to release energy in the form of ATP.
• Glycolysis is the initial stage, occurring in the cytoplasm.
• The Krebs cycle (citric acid cycle) takes place in the mitochondrial matrix.
• The electron transport chain (ETC) occurs across the inner mitochondrial membrane.
• Aerobic respiration requires oxygen, yielding a high amount of ATP.
• Anaerobic respiration (fermentation) occurs in the absence of oxygen, producing less ATP.

Photosynthesis

• Photosynthesis is the process by which plants and other organisms convert light energy into chemical energy (glucose).
• Photosynthesis takes place in chloroplasts, specifically the thylakoid membranes.
• Light-dependent reactions capture light energy and produce ATP and NADPH.
• Dark reactions (Calvin cycle) utilize ATP and NADPH to fix carbon dioxide and synthesize glucose.

Genetics

• Genetics is the study of heredity and variation in organisms.
• Genes are segments of DNA that code for specific traits.
• DNA carries the genetic information in a double helix structure.
• DNA replication ensures the accurate duplication of genetic material.
• Transcription converts DNA information into mRNA.
• Translation uses mRNA to synthesize proteins.
• Mutations are changes in DNA sequence, which can lead to variations.

Evolution

• Evolution is the change in heritable characteristics of biological populations over successive generations.
• Natural selection is a key mechanism of evolution, where organisms with advantageous traits are more likely to survive and reproduce.
• Adaptation is the process by which organisms become better suited to their environment.
• Common ancestry connects all life forms on Earth.
• Speciation is the formation of new species from existing ones.

Ecology

• Ecology is the study of the relationships between organisms and their environment.
• Ecosystems encompass all living organisms (biotic factors) and non-living components (abiotic factors) in a specific area.
• Food chains and food webs represent the flow of energy and nutrients through an ecosystem.
• Population dynamics examines factors affecting population size and growth.
• Biodiversity is the variety of life in all its forms.
• Conservation biology focuses on the preservation of species and ecosystems.

Classification

• Organisms are classified into a hierarchical system of taxonomic ranks, from domain to species.
• The three domains of life are Bacteria, Archaea, and Eukarya.
• Taxonomic keys are used to identify organisms based on observable characteristics.

Biotechnology

• Biotechnology involves using living organisms or their products for technological applications.
• Genetic engineering modifies the genetic material of an organism to produce desired traits.
• Recombinant DNA technology joins DNA sequences from different sources.
• Applications include pharmaceuticals, agriculture, and industrial processes.

Explore the fascinating world of cell structure and function, focusing on the differences between prokaryotic and eukaryotic cells. Delve into the process of cellular respiration, including glycolysis, the Krebs cycle, and the electron transport chain, to understand how energy is produced in cells.