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Biology Class Notes

Biology is the scientific study of life, encompassing various branches such as zoology, botany, and genetics. Key characteristics of living things include cellular composition, energy use, growth, reproduction, and evolution. The document also covers cell structure, photosynthesis, genetics, biological molecules, classification of life, ecology basics, human body systems, and the scientific method.

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11 views4 pages

Biology Class Notes

Biology is the scientific study of life, encompassing various branches such as zoology, botany, and genetics. Key characteristics of living things include cellular composition, energy use, growth, reproduction, and evolution. The document also covers cell structure, photosynthesis, genetics, biological molecules, classification of life, ecology basics, human body systems, and the scientific method.

Uploaded by

lavaniboodhan
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© © All Rights Reserved
We take content rights seriously. If you suspect this is your content, claim it here.
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🧬 Biology Class Notes

📘 1. What is Biology?
Definition:
Biology is the scientific study of life and living organisms.

Main Branches:

 Zoology – study of animals


 Botany – study of plants
 Microbiology – study of microorganisms
 Genetics – study of heredity
 Ecology – study of organisms and their environment

🔬 2. Characteristics of Living Things


All living things:

1. Are made of cells


2. Use energy
3. Grow and develop
4. Reproduce
5. Respond to stimuli
6. Maintain homeostasis
7. Evolve over time

🧱 3. Cell Structure and Function


Types of Cells:

 Prokaryotic – no nucleus (e.g., bacteria)


 Eukaryotic – with nucleus (e.g., plant and animal cells)

Key Organelles:
Organelle Function
Nucleus Contains DNA
Mitochondria Produces energy (ATP)
Ribosomes Make proteins
Endoplasmic Reticulum (ER) Transports materials
Golgi Apparatus Packages and ships proteins
Lysosomes Break down waste
Chloroplast (plants) Photosynthesis
Cell Wall (plants) Structure and support

🌱 4. Photosynthesis and Cellular Respiration


Photosynthesis (in plants):

Equation:
6CO₂ + 6H₂O + sunlight → C₆H₁₂O₆ + 6O₂
(Uses sunlight to make glucose)

Cellular Respiration (in animals & plants):

Equation:
C₆H₁₂O₆ + 6O₂ → 6CO₂ + 6H₂O + ATP
(Breaks down glucose for energy)

🧬 5. Genetics and DNA


DNA (Deoxyribonucleic Acid):

 Double helix structure


 Made of nucleotides: A, T, C, G
 A pairs with T, C pairs with G

Mendelian Genetics:

 Dominant vs. Recessive traits


 Genotype = genetic makeup (e.g., Aa)
 Phenotype = physical trait (e.g., tall)
 Use Punnett Squares to predict inheritance
💦 6. Biological Molecules
4 Major Macromolecules:

Type Monomer Function


Carbohydrates Monosaccharides Energy
Proteins Amino acids Enzymes, structure
Lipids Fatty acids Energy storage
Nucleic Acids Nucleotides Genetic info (DNA/RNA)

🧫 7. Classification of Life
Levels of Classification:

 Domain
 Kingdom
 Phylum
 Class
 Order
 Family
 Genus
 Species

Mnemonic: “Dear King Philip Came Over For Good Soup”

🌎 8. Ecology Basics
Key Terms:

 Ecosystem – community + environment


 Habitat – where an organism lives
 Niche – an organism’s role in its ecosystem
 Food Chain – linear flow of energy
 Food Web – interconnected food chains
 Producers – make their own food (plants)
 Consumers – eat other organisms

🧠 9. Human Body Systems (Overview)


System Function
Digestive Breaks down food
Respiratory Gas exchange
Circulatory Transports nutrients and oxygen
Nervous Sends signals through the body
Muscular Movement
Skeletal Support and structure
Immune Defends against disease

📊 10. Scientific Method


1. Ask a question
2. Form a hypothesis
3. Conduct an experiment
4. Analyze data
5. Draw conclusions
6. Report results

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