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

Test your knowledge of cell biology, including the structure and functions of cell components such as the plasma membrane, cytoplasm, nucleus, and more.