Biology: Cell Structure and Functions

Biology Study Notes

Cell Biology

• Cell Structure:
  • Plasma membrane: semi-permeable membrane that separates cell from environment
  • Cytoplasm: jelly-like substance inside cell where metabolic reactions occur
  • Nucleus: contains DNA, controls cell growth and reproduction
  • Mitochondria: generates energy for cell through cellular respiration
  • Endoplasmic reticulum: involved in protein synthesis and transport
  • Ribosomes: site of protein synthesis
• Cellular Processes:
  • Photosynthesis: process by which cells convert light energy into chemical energy
  • Cellular respiration: process by which cells generate energy from glucose
  • Mitosis: process of cell division that results in two identical daughter cells

Genetics

• Mendelian Genetics:
  • Laws of inheritance: segregation, independent assortment, and dominance
  • Genotype: genetic makeup of an individual
  • Phenotype: physical expression of an individual's genotype
• DNA Structure:
  • Double helix model: two complementary strands of nucleotides
  • Nucleotides: composed of sugar, phosphate, and nitrogenous bases
• Genetic Variation:
  • Mutations: changes in DNA sequence
  • Genetic recombination: process of exchanging genetic information between chromosomes

Evolution

• Key Principles:
  • Descent with modification: all organisms share a common ancestor
  • Variation and adaptation: populations evolve through genetic variation and adaptation to environment
  • Natural selection: process by which individuals with favorable traits are more likely to survive and reproduce
• Evidence for Evolution:
  • Fossil record: chronological record of evolutionary history
  • Comparative anatomy: similarities and differences between body structures
  • Molecular biology: similarities and differences between DNA and protein sequences

Lungs

• Structure:
  • Trachea: divides into two bronchi, which further divide into bronchioles
  • Alveoli: small air sacs where gas exchange occurs
• Function:
  • Gas exchange: oxygen diffuses into bloodstream, carbon dioxide diffuses out
  • Respiration: process of breathing in and out

Animal Cell

• Unique Features:
  • Lack of cell wall: allows for flexibility and movement
  • Centrioles: involved in formation of cilia and flagella
  • Lysosomes: contain digestive enzymes for breaking down cellular waste
• Cellular Processes:
  • Endocytosis: process of taking in molecules and particles from environment
  • Exocytosis: process of releasing molecules and particles from cell

Cell Biology

• Cell Structure:
  • Plasma membrane separates cell from environment and regulates what enters and leaves cell
  • Cytoplasm is jelly-like substance inside cell where metabolic reactions occur
  • Nucleus contains DNA and controls cell growth and reproduction
  • Mitochondria generates energy for cell through cellular respiration
  • Endoplasmic reticulum involved in protein synthesis and transport
  • Ribosomes are site of protein synthesis
• Cellular Processes:
  • Photosynthesis converts light energy into chemical energy
  • Cellular respiration generates energy for cell from glucose
  • Mitosis is process of cell division that results in two identical daughter cells

Genetics

• Mendelian Genetics:
  • Laws of inheritance include segregation, independent assortment, and dominance
  • Genotype is genetic makeup of an individual
  • Phenotype is physical expression of an individual's genotype
• DNA Structure:
  • Double helix model consists of two complementary strands of nucleotides
  • Nucleotides composed of sugar, phosphate, and nitrogenous bases
• Genetic Variation:
  • Mutations are changes in DNA sequence
  • Genetic recombination is process of exchanging genetic information between chromosomes

Evolution

• Key Principles:
  • Descent with modification: all organisms share a common ancestor
  • Variation and adaptation: populations evolve through genetic variation and adaptation to environment
  • Natural selection: process by which individuals with favorable traits are more likely to survive and reproduce
• Evidence for Evolution:
  • Fossil record provides chronological record of evolutionary history
  • Comparative anatomy shows similarities and differences between body structures
  • Molecular biology shows similarities and differences between DNA and protein sequences

Lungs

• Structure:
  • Trachea divides into two bronchi, which further divide into bronchioles
  • Alveoli are small air sacs where gas exchange occurs
• Function:
  • Gas exchange: oxygen diffuses into bloodstream, carbon dioxide diffuses out
  • Respiration is process of breathing in and out

Animal Cell

• Unique Features:
  • Lack of cell wall allows for flexibility and movement
  • Centrioles are involved in formation of cilia and flagella
  • Lysosomes contain digestive enzymes for breaking down cellular waste
• Cellular Processes:
  • Endocytosis is process of taking in molecules and particles from environment
  • Exocytosis is process of releasing molecules and particles from cell