Biology Fundamentals: Cells and Biological Molecules

Cells

• Basic structural and functional units of life
• Consist of:
  • Cell membrane (plasma membrane): semi-permeable membrane that separates cell from environment
  • Cytoplasm: jelly-like substance inside cell membrane
  • Nucleus: contains genetic material (DNA)
• Cell types:
  • Prokaryotic cells: lack true nucleus, e.g. bacteria
  • Eukaryotic cells: have true nucleus, e.g. plants, animals, fungi

Biological Molecules

• Carbohydrates:
  • Provide energy and structure for cells
  • Examples: glucose, starch, cellulose
• Proteins:
  • Perform various functions, e.g. enzymes, hormones, structural components
  • Examples: hemoglobin, insulin, collagen
• Lipids:
  • Provide energy and structure for cells
  • Examples: fats, oils, cholesterol
• Nucleic acids:
  • Contain genetic information (DNA, RNA)
  • Examples: DNA, RNA

Variety of Living Organisms

• Classification:
  • Domain: highest level of classification
  • Kingdom: second level of classification
  • Phylum: third level of classification
  • Class: fourth level of classification
  • Order: fifth level of classification
  • Family: sixth level of classification
  • Genus: seventh level of classification
  • Species: most specific level of classification
• Types of organisms:
  • Monera: single-celled organisms, e.g. bacteria
  • Protista: single-celled eukaryotes, e.g. protozoa
  • Fungi: e.g. mushrooms, yeast
  • Plantae: e.g. plants, trees
  • Animalia: e.g. animals, humans

Enzymes

• Biological molecules that catalyze chemical reactions
• Characteristics:
  • Specificity: each enzyme has a specific substrate
  • Optimized temperature and pH: enzymes work best at specific temperatures and pH levels
  • Increased reaction rate: enzymes speed up chemical reactions
• Types of enzymes:
  • Amylase: breaks down starch
  • Protease: breaks down proteins
  • Lipase: breaks down lipids

Digestion

• Breakdown of food into smaller molecules that can be absorbed and utilized by the body
• Digestive system:
  • Mouth: mechanical and chemical breakdown of food (saliva contains amylase)
  • Stomach: chemical breakdown of food (gastric acid and pepsin)
  • Small intestine: absorption of nutrients
  • Large intestine: water absorption and waste elimination
• Importance of digestion:
  • Provides energy and nutrients for the body

Gas Exchange in Humans

• Process of exchanging oxygen and carbon dioxide between the environment and the body
• Respiratory system:
  • Nose and mouth: air enters the body
  • Trachea: air passes through the trachea
  • Bronchi: air passes through the bronchi
  • Alveoli: gas exchange occurs
• Process of gas exchange:
  • Oxygen diffuses into the bloodstream
  • Carbon dioxide diffuses out of the bloodstream
  • Importance of gas exchange:
    • Provides oxygen for cellular respiration
    • Removes waste product (carbon dioxide)

Cells

• Cells are the basic structural and functional units of life
• Cell components include:
  • Cell membrane (plasma membrane): semi-permeable membrane separating cell from environment
  • Cytoplasm: jelly-like substance inside cell membrane
  • Nucleus: contains genetic material (DNA)
• Cell types:
  • Prokaryotic cells: lack true nucleus, e.g. bacteria
  • Eukaryotic cells: have true nucleus, e.g. plants, animals, fungi

Biological Molecules

• Carbohydrates:
  • Provide energy and structure for cells
  • Examples: glucose, starch, cellulose
• Proteins:
  • Perform various functions, e.g. enzymes, hormones, structural components
  • Examples: hemoglobin, insulin, collagen
• Lipids:
  • Provide energy and structure for cells
  • Examples: fats, oils, cholesterol
• Nucleic acids:
  • Contain genetic information (DNA, RNA)
  • Examples: DNA, RNA

Variety of Living Organisms

• Classification levels:
  • Domain: highest level of classification
  • Kingdom: second level of classification
  • Phylum: third level of classification
  • Class: fourth level of classification
  • Order: fifth level of classification
  • Family: sixth level of classification
  • Genus: seventh level of classification
  • Species: most specific level of classification
• Types of organisms:
  • Monera: single-celled organisms, e.g. bacteria
  • Protista: single-celled eukaryotes, e.g. protozoa
  • Fungi: e.g. mushrooms, yeast
  • Plantae: e.g. plants, trees
  • Animalia: e.g. animals, humans

Enzymes

• Enzymes are biological molecules that catalyze chemical reactions
• Characteristics:
  • Specificity: each enzyme has a specific substrate
  • Optimized temperature and pH: enzymes work best at specific temperatures and pH levels
  • Increased reaction rate: enzymes speed up chemical reactions
• Examples of enzymes:
  • Amylase: breaks down starch
  • Protease: breaks down proteins
  • Lipase: breaks down lipids

Digestion

• Digestion is the breakdown of food into smaller molecules that can be absorbed and utilized by the body
• Digestive system components:
  • Mouth: mechanical and chemical breakdown of food (saliva contains amylase)
  • Stomach: chemical breakdown of food (gastric acid and pepsin)
  • Small intestine: absorption of nutrients
  • Large intestine: water absorption and waste elimination
• Importance of digestion:
  • Provides energy and nutrients for the body

Gas Exchange in Humans

• Gas exchange is the process of exchanging oxygen and carbon dioxide between the environment and the body
• Respiratory system components:
  • Nose and mouth: air enters the body
  • Trachea: air passes through the trachea
  • Bronchi: air passes through the bronchi
  • Alveoli: gas exchange occurs
• Process of gas exchange:
  • Oxygen diffuses into the bloodstream
  • Carbon dioxide diffuses out of the bloodstream
• Importance of gas exchange:
  • Provides oxygen for cellular respiration
  • Removes waste product (carbon dioxide)