Biology Chapters 1-2

Branches of Biology

• Botany: study of plants
• Zoology: study of animals
• Microbiology: study of microorganisms
• Ecology: study of interactions between organisms and their environment

Cell Biology

• Cell: basic unit of life
  • Prokaryotic cells (no nucleus): bacteria
  • Eukaryotic cells (with nucleus): plants, animals, fungi, protists
• Cell membrane: semi-permeable membrane that separates cell from environment
• Cell organelles:
  1. Nucleus: contains genetic material (DNA)
  2. Mitochondria: generates energy for cell
  3. Ribosomes: site of protein synthesis
  4. Endoplasmic reticulum: involved in protein synthesis and transport
  5. Lysosomes: contains digestive enzymes

Genetics

• DNA (Deoxyribonucleic acid): genetic material that carries information
• Genes: segments of DNA that code for specific traits
• Chromosomes: thread-like structures that carry genes
• Inheritance:
  • Dominant and recessive traits
  • Mendel's laws of inheritance

Evolution

• Charles Darwin's theory of evolution by natural selection
• Mechanisms of evolution:
  • Mutation
  • Genetic drift
  • Gene flow
  • Natural selection
• Evidence for evolution:
  • Fossil record
  • Comparative anatomy
  • Molecular biology

Ecology

• Ecosystem: community of organisms and their environment
• Energy flow:
  • Producers (plants): convert sunlight into energy
  • Consumers (animals): obtain energy by consuming other organisms
• Nutrient cycles:
  • Carbon cycle
  • Nitrogen cycle
  • Water cycle

Biological Molecules

• Carbohydrates: energy source for cells
• Proteins: structural and functional molecules
• Lipids: energy storage and structure
• Nucleic acids: DNA and RNA

Biological Processes

• Photosynthesis: process by which plants convert sunlight into energy
• Respiration: process by which cells generate energy
• Fermentation: process by which cells generate energy in absence of oxygen

Branches of Biology

• Botany focuses on the study of plants, including their structure, growth, reproduction, and metabolism.
• Zoology involves the study of animals, exploring their behavior, physiology, and taxonomy.
• Microbiology investigates microorganisms, covering bacteria, viruses, fungi, and protozoa.
• Ecology examines the interactions between organisms and their environments, emphasizing ecosystems and biodiversity.

Cell Biology

• A cell is the fundamental unit of life, classified into two types:
  • Prokaryotic cells lack a nucleus and include bacteria.
  • Eukaryotic cells contain a nucleus and are found in plants, animals, fungi, and protists.
• The cell membrane is a semi-permeable barrier that regulates entry and exit of substances.
• Cell organelles perform specific functions:
  • The nucleus stores genetic material (DNA).
  • Mitochondria generate energy via cellular respiration.
  • Ribosomes are the sites of protein synthesis.
  • The endoplasmic reticulum is involved in protein synthesis and transport.
  • Lysosomes contain digestive enzymes for breaking down waste materials.

Genetics

• DNA (Deoxyribonucleic acid) is the hereditary material responsible for storing and transmitting genetic information.
• Genes are segments of DNA that code for specific traits.
• Chromosomes are structures that organize DNA within the nucleus, consisting of genes.
• Inheritance principles include:
  • Dominant traits overshadow recessive traits in phenotype expression.
  • Mendel's laws of inheritance describe how traits are passed from parents to offspring.

Evolution

• Charles Darwin proposed the theory of evolution by natural selection, explaining how species adapt and evolve over time.
• Evolution mechanisms include:
  • Mutation introduces genetic variation.
  • Genetic drift leads to changes in allele frequencies within a population.
  • Gene flow is the transfer of genetic material between populations.
  • Natural selection favors advantageous traits for survival and reproduction.
• Evidence supporting evolution comes from:
  • The fossil record, which shows historical life forms.
  • Comparative anatomy, revealing similarities among species.
  • Molecular biology, which analyzes genetic material across different organisms.

Ecology

• An ecosystem comprises a community of organisms and their physical environment.
• Energy flow within ecosystems involves:
  • Producers (plants) converting sunlight into energy through photosynthesis.
  • Consumers (animals) obtaining energy by feeding on other organisms.
• Nutrient cycles are essential for ecosystem sustainability:
  • The carbon cycle regulates carbon's movement through the environment.
  • The nitrogen cycle describes the conversion of nitrogen in various forms within ecosystems.
  • The water cycle outlines the movement of water through evaporation, condensation, and precipitation.

Biological Molecules

• Carbohydrates serve as primary energy sources and structural components in cells.
• Proteins fulfill various functions, including catalyzing reactions and providing structure.
• Lipids are important for energy storage and cellular structure as part of membrane composition.
• Nucleic acids, namely DNA and RNA, are crucial for genetic information storage and transmission.

Biological Processes

• Photosynthesis enables plants to convert sunlight into chemical energy, producing glucose and oxygen.
• Respiration is a cellular process that generates energy by breaking down glucose in the presence of oxygen.
• Fermentation occurs when cells derive energy from glucose in the absence of oxygen, producing by-products like alcohol or lactic acid.