Biology Basics

Biology

Branches of Biology

• Botany: study of plants
• Zoology: study of animals
• Microbiology: study of microorganisms (bacteria, viruses, fungi)
• Ecology: study of relationships between organisms and their environment

Cell Biology

• Cell structure:
  • Plasma membrane
  • Cytoplasm
  • Nucleus
  • Mitochondria
  • Endoplasmic reticulum
• Cellular processes:
  • Metabolism
  • Photosynthesis
  • Cell division (mitosis, meiosis)

Genetics

• Mendelian inheritance: laws of inheritance (segregation, independent assortment, dominance)
• DNA structure: double helix model
• Genetic code: sequence of nucleotides determines amino acid sequence
• Genetic variation: mutation, genetic drift, gene flow, natural selection

Evolution

• Theory of evolution: species change over time through natural selection
• Mechanisms of evolution:
  • Mutation
  • Genetic drift
  • Gene flow
  • Natural selection
• Evidence for evolution:
  • Fossil record
  • Comparative anatomy
  • Molecular biology

Ecology and Ecosystems

• Ecosystem components:
  • Biotic factors (living organisms)
  • Abiotic factors (non-living environment)
• Energy flow: producers, consumers, decomposers
• Ecosystem services: provisioning, regulating, cultural, supporting services

Biology

Branches of Biology

• Botany is the study of plants
• Zoology is the study of animals
• Microbiology is the study of microorganisms such as bacteria, viruses, and fungi
• Ecology is the study of relationships between organisms and their environment

Cell Biology

Cell Structure

• Plasma membrane is a semi-permeable membrane that separates the cell from its environment
• Cytoplasm is the jelly-like substance inside the cell membrane
• Nucleus is the control center of the cell where DNA is stored
• Mitochondria are the powerhouses of the cell responsible for generating energy
• Endoplasmic reticulum is a network of membranous tubules and cisternae involved in protein synthesis and transport

Cellular Processes

• Metabolism is the process of converting energy and nutrients into components that make up living organisms
• Photosynthesis is the process by which plants convert light energy into chemical energy
• Cell division occurs through mitosis and meiosis, resulting in the production of new cells

Genetics

Mendelian Inheritance

• The law of segregation states that each pair of alleles separates from each other during gamete formation
• The law of independent assortment states that alleles for different genes are sorted independently of each other
• The law of dominance states that one allele can be dominant over another allele

DNA Structure

• DNA is structured as a double helix model with sugar and phosphate molecules making up the backbone and nitrogenous bases projecting inward from the backbone
• DNA is composed of four nitrogenous bases: adenine, guanine, cytosine, and thymine

Genetic Code

• The sequence of nucleotides determines the amino acid sequence of proteins
• The genetic code is degenerate, meaning that more than one codon can code for the same amino acid

Genetic Variation

• Mutation is a change in the DNA sequence of an organism
• Genetic drift is the random change in the frequency of an allele in a population
• Gene flow is the movement of alleles from one population to another
• Natural selection is the process by which individuals with favorable traits are more likely to survive and reproduce

Evolution

Theory of Evolution

• Species change over time through the process of natural selection
• Evolution is a gradual and ongoing process that has shaped the diversity of life on Earth

Mechanisms of Evolution

• Mutation is a source of genetic variation
• Genetic drift can lead to the loss or fixation of alleles in a population
• Gene flow can increase genetic variation in a population
• Natural selection acts on existing genetic variation to favor the survival and reproduction of individuals with favorable traits

Evidence for Evolution

• The fossil record shows a pattern of gradual changes in the characteristics of ancient organisms
• Comparative anatomy reveals similarities and homologies between different species
• Molecular biology provides evidence for evolution through the similarity of DNA and protein sequences between different species

Introduction to biology, covering branches of biology, cell biology, and genetics. Explore botany, zoology, microbiology, ecology, cell structure, cellular processes, and genetics.