Cell Structure and Function

Cell Structure and Function

• Cells are the basic unit of life, exhibiting diverse structures and functions.
• Prokaryotic cells (e.g., bacteria) lack a nucleus and membrane-bound organelles.
• Eukaryotic cells (e.g., plant and animal cells) possess a nucleus and various organelles.
• The cell membrane acts as a selective barrier, regulating the passage of substances.
• The nucleus contains the cell's genetic material (DNA).
• Ribosomes are responsible for protein synthesis.
• Mitochondria are the powerhouses of the cell; they generate ATP (energy).
• Endoplasmic reticulum (ER) is involved in protein synthesis and lipid metabolism.
• Golgi apparatus processes and packages proteins.
• Lysosomes contain digestive enzymes for waste breakdown.
• Vacuoles store water and nutrients.
• Cytoskeleton provides structural support and facilitates cell movement.
• Chloroplasts (in plant cells) conduct photosynthesis.

Biological Molecules

• Four major classes of biological macromolecules: carbohydrates, lipids, proteins, and nucleic acids.
• Carbohydrates are composed of carbon, hydrogen, and oxygen; serve as energy sources and structural components.
• Lipids are diverse hydrophobic molecules; include fats, oils, and phospholipids (important for cell membranes).
• Proteins are polymers of amino acids; perform diverse functions, including enzymes, structural support, and transport.
• Nucleic acids (DNA and RNA) store and transmit genetic information.

Cellular Respiration

• Cellular respiration is the process by which cells break down glucose to release energy.
• Stages include glycolysis, Krebs cycle, and electron transport chain.
• Glycolysis occurs in the cytoplasm; breaks down glucose into pyruvate.
• Krebs cycle takes place within the mitochondria; generates high-energy electron carriers.
• Electron transport chain in the mitochondrial inner membrane produces a large amount of ATP.

Photosynthesis

• Photosynthesis is the process by which plants and some other organisms convert light energy into chemical energy.
• Takes place in chloroplasts.
• Involves light-dependent and light-independent reactions (Calvin cycle).
• Light-dependent reactions capture light energy to produce ATP and NADPH.
• Light-independent reactions use ATP and NADPH to synthesize glucose.

Genetics

• Genes are segments of DNA that code for specific traits.
• DNA replication ensures accurate duplication of genetic material.
• Gene expression involves transcription (DNA to RNA) and translation (RNA to protein).
• Mutations can alter DNA sequences, potentially leading to changes in traits.
• Chromosomes are structures carrying DNA.
• Mendelian genetics explains patterns of inheritance of traits.
• Chromosomes, during cell division, must divide in a way that ensures the proper distribution of genetic material.

Ecology

• Ecology studies interactions between organisms and their environment.
• Levels of organization include populations, communities, ecosystems, and biomes.
• Abiotic factors (non-living) and biotic factors (living) influence ecological processes.
• Food chains and food webs describe energy flow through ecosystems.
• Symbiotic relationships (mutualism, parasitism, commensalism) are crucial in ecosystems.
• Human activities significantly influence ecosystems.

Evolution

• Evolution is the change in the heritable characteristics of biological populations over successive generations.
• Natural selection is a key mechanism of evolution, favouring traits that enhance survival and reproduction.
• Common ancestry explains the relatedness of different species.
• Evidence for evolution includes fossil records, comparative anatomy, molecular biology.
• Mechanisms like genetic drift and gene flow also contribute to evolution.

Classification

• Taxonomy involves classifying and naming organisms based on shared characteristics.
• Hierarchical classification system (Kingdom, Phylum, Class, Order, Family, Genus, Species).
• Binomial nomenclature (e.g., Homo sapiens) uses genus and species names.
• Different classification systems exist, often reflecting current understanding of evolutionary relationships.

Explore the fascinating world of cell biology with this quiz on cell structure and function. Understand the differences between prokaryotic and eukaryotic cells, learn about organelles and their roles, and discover how these components work together to sustain life. Test your knowledge on the essential aspects of cellular biology!