Biology Fundamentals

Cell Structure

• Cell Membrane: semi-permeable, regulates what enters and leaves the cell
• Cytoplasm: jelly-like substance inside the cell membrane, contains organelles
• Organelles:
  • Nucleus: contains DNA, controls cell growth and reproduction
  • Mitochondria: generates energy for the cell through cellular respiration
  • Endoplasmic Reticulum (ER): transports proteins and lipids
  • Ribosomes: site of protein synthesis
  • Lysosomes: contains digestive enzymes, breaks down waste and foreign substances
  • Golgi Apparatus: modifies and packages proteins and lipids for transport

Human Physiology

• Nervous System:
  • Central Nervous System (CNS): brain and spinal cord, integrates and processes information
  • Peripheral Nervous System (PNS): nerves, transmits information to and from CNS
• Circulatory System:
  • Heart: pumps blood throughout the body
  • Blood Vessels: arteries, veins, and capillaries, transport oxygen and nutrients
• Respiratory System:
  • Lungs: exchange oxygen and carbon dioxide
  • Trachea: airway that leads to the lungs
• Digestive System:
  • Mouth: begins mechanical and chemical digestion
  • Stomach: mixes food with digestive enzymes
  • Small Intestine: absorbs nutrients into the bloodstream
  • Large Intestine: absorbs water and electrolytes, stores waste

Photosynthesis

• Light-Dependent Reactions:
  • Light Absorption: light energy is absorbed by pigments (e.g. chlorophyll)
  • Electron Transport: light energy is converted into ATP and NADPH
• Light-Independent Reactions (Calvin Cycle):
  • Carbon Fixation: CO2 is fixed into a 3-carbon molecule
  • Reduction Reactions: 3-carbon molecule is reduced to form glucose
• Overall Equation: 6 CO2 + 6 H2O + light energy → C6H12O6 (glucose) + 6 O2

Genetics

• Mendel's Laws:
  • Law of Segregation: each pair of alleles separates during gamete formation
  • Law of Independent Assortment: alleles for different genes are sorted independently
  • Law of Dominance: dominant alleles are expressed over recessive alleles
• DNA Structure:
  • Double Helix: two complementary strands of nucleotides
  • Nucleotides: composed of sugar, phosphate, and nitrogenous bases
• Genotype: genetic makeup of an individual
• Phenotype: physical expression of an individual's genotype

Ecosystems

• Biotic Factors: living components of an ecosystem (e.g. plants, animals, microorganisms)
• Abiotic Factors: non-living components of an ecosystem (e.g. water, sunlight, temperature)
• Energy Flow:
  • Producers: organisms that convert sunlight into energy (e.g. plants)
  • Consumers: organisms that obtain energy by consuming other organisms
  • Decomposers: organisms that break down organic matter
• Food Webs: complex networks of energy flow through an ecosystem

NCERT

• NCERT Books: textbooks published by the National Council of Educational Research and Training (India)
• Biology Curriculum: covers topics such as cell structure, genetics, evolution, and ecology
• Importance: provides a comprehensive and standardized education in biology for students in India