Biology: Branches and Cell Structure

Branches of Biology

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

Cell Biology

• Cell: basic unit of life, consists of:
  • Plasma membrane: outer layer, regulates what enters/leaves cell
  • Cytoplasm: jelly-like substance inside cell, site of metabolic reactions
  • Nucleus: contains genetic material (DNA)
  • Mitochondria: site of cellular respiration (energy production)
• Cellular processes:
  • Photosynthesis: conversion of light energy to chemical energy
  • Cellular respiration: breakdown of glucose to produce energy

Genetics

• Heredity: passing of traits from parents to offspring
• Genetic code: sequence of nucleotides (A, C, G, T) in DNA that determines traits
• Inheritance patterns:
  • Dominant/recessive traits
  • Autosomal dominant/recessive traits
  • X-linked traits

Evolution

• Theory of evolution: gradual change in species over time through natural selection
• Mechanisms of evolution:
  • Mutation: change in DNA sequence
  • Genetic drift: random change in gene pool
  • Gene flow: movement of genes between populations
• Evidence for evolution:
  • Fossil record
  • Comparative anatomy
  • Molecular biology

Ecology

• Ecosystem: community of organisms and their environment
• Energy flow:
  • Producers (plants): convert sunlight to energy
  • Consumers (herbivores, carnivores, omnivores): obtain energy by consuming other organisms
  • Decomposers (bacteria, fungi): break down organic matter
• Population dynamics:
  • Growth rates
  • Limiting factors (resources, predators, disease)

Branches of Biology

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

Cell Biology

• The cell is the basic unit of life
• Plasma membrane regulates what enters and leaves the cell
• Cytoplasm is a jelly-like substance inside the cell where metabolic reactions occur
• The nucleus contains genetic material in the form of DNA
• Mitochondria are the site of cellular respiration where energy is produced
• Photosynthesis is the conversion of light energy to chemical energy
• Cellular respiration is the breakdown of glucose to produce energy

Genetics

• Heredity is the passing of traits from parents to offspring
• The genetic code is a sequence of nucleotides (A, C, G, T) in DNA that determines traits
• Dominant and recessive traits are determined by the genetic code
• Autosomal dominant and recessive traits are related to genes on non-sex chromosomes
• X-linked traits are related to genes on the X chromosome
• Inheritance patterns can be predicted using the genetic code

Evolution

• The theory of evolution states that species change over time through natural selection
• Mutation is a change in the DNA sequence
• Genetic drift is a random change in the gene pool
• Gene flow is the movement of genes between populations
• The fossil record, comparative anatomy, and molecular biology provide evidence for evolution
• Evolution occurs through the gradual change in species over time

Ecology

• An ecosystem is a community of organisms and their environment
• Producers convert sunlight to energy through photosynthesis
• Consumers obtain energy by consuming other organisms
• Decomposers break down organic matter
• Energy flows from producers to consumers to decomposers
• Population growth rates are affected by limiting factors such as resources, predators, and disease