Cell Structure and Biological Molecules

Cell Structure and Function

• Cells are the basic units of life, exhibiting a complex internal structure.
• Prokaryotic cells (like bacteria) lack a nucleus and membrane-bound organelles.
• Eukaryotic cells (like animal and plant cells) contain a nucleus and various organelles.
• The plasma membrane forms a boundary, selectively permeable to substances.
• The nucleus houses the cell's genetic material (DNA).
• Ribosomes synthesize proteins.
• Mitochondria are the powerhouse of the cell, responsible for energy production (ATP).
• The endoplasmic reticulum (ER) is involved in protein and lipid synthesis.
• The Golgi apparatus modifies, sorts, and packages proteins.
• Lysosomes contain digestive enzymes to break down waste.
• Vacuoles store water and nutrients.
• Cytoskeleton provides structural support.

Biological Molecules

• Carbohydrates provide energy and structural support. Simple sugars (monosaccharides) are the basic unit.
• Lipids store energy, form structural components of cells (phospholipids), and act as hormones.
• Proteins perform diverse functions, including enzymes, hormones, and structural components (collagen).
• Nucleic acids (DNA and RNA) store and transmit genetic information.

Photosynthesis

• Photosynthesis is the process by which green plants and other organisms use sunlight to synthesize foods from carbon dioxide and water.
• The process takes place in chloroplasts.
• Sunlight is captured by chlorophyll.
• Chlorophyll absorbs light energy, converting it into chemical energy.
• Water is split, releasing oxygen as a byproduct.
• Carbon dioxide is incorporated into sugars (glucose).

Cellular Respiration

• Cellular respiration is the process by which cells break down glucose to release energy in the form of ATP.
• This process can be aerobic (requiring oxygen) or anaerobic (without oxygen).
• Aerobic respiration occurs in the mitochondria.
• Glucose is oxidized, releasing energy, and producing carbon dioxide and water.
• ATP is generated as a result of the breakdown of glucose.
• Anaerobic respiration produces less ATP than aerobic respiration.

Genetics

• Genes are segments of DNA that carry hereditary information.
• DNA carries the genetic code.
• DNA replication is the process of making copies of DNA.
• Transcription is the process of copying the genetic information from DNA into RNA.
• Translation is the process of using the information in RNA to synthesize proteins.
• Mutations are changes in the DNA sequence, causing variations.

Evolution

• Evolution is the process of gradual change in the inherited characteristics of biological populations over successive generations.
• Natural selection is a key mechanism of evolution.
• Organisms with traits better suited to their environment are more likely to survive and reproduce.
• Variations arise through mutations and genetic recombination.
• Adaptations are traits that enhance survival and reproduction in a specific environment.

Ecology

• Ecology is the study of the relationships between organisms and their environment.
• Ecosystems consist of biotic (living) and abiotic (non-living) components.
• Organisms interact with each other (e.g., predation, competition).
• Energy flows through ecosystems.
• Nutrients cycle through ecosystems.
• Biodiversity is the variety of life in an area.

Biological Diversity

• Biological diversity encompasses the variety of life at all levels, from genes to ecosystems.
• Speciation is the process by which new species arise.
• Extinction is the disappearance of a species.
• Biodiversity is important for ecosystem functioning and human well-being.

Classification

• Organisms are classified into hierarchical groups based on shared characteristics.
• The hierarchy includes domain, kingdom, phylum, class, order, family, genus, and species.
• Classification systems reflect evolutionary relationships.

Explore the essential components of cells, including the differences between prokaryotic and eukaryotic cells. This quiz covers cell organelles, their functions, and the role of biological molecules like carbohydrates and lipids. Test your knowledge of cellular anatomy and biological chemistry.