Biology Branches and Cell Basics

Cell: basic unit of life
Cellular components:
- Nucleus: contains genetic material
- Mitochondria: generates energy for the cell
- Ribosomes: site of protein synthesis
- Lysosomes: contain digestive enzymes
Cellular processes:
- Photosynthesis: conversion of light energy into chemical energy
- Respiration: process of generating energy from glucose

Mendelian Genetics:
- Laws of Inheritance:
  - Law of Segregation: each trait is determined by two alleles
  - Law of Independent Assortment: alleles for different traits are sorted independently
  - Law of Dominance: dominant allele is expressed over recessive allele
- Inheritance patterns:
  - Autosomal dominant
  - Autosomal recessive
  - X-linked dominant
  - X-linked recessive
Molecular Genetics:
- DNA structure: double helix model
- DNA replication: process of creating an exact copy of DNA
- Gene expression: process of creating a functional product from a gene

Theory of Evolution: species change over time through natural selection
Mechanisms of Evolution:
- Mutation: change in DNA sequence
- Genetic drift: random change in allele frequency
- Gene flow: movement of genes from one population to another
- Natural selection: survival and reproduction of individuals with advantageous traits
Evidence for Evolution:
- Fossil record: sequence of fossils shows gradual changes over time
- Comparative anatomy: similar structures in different species
- Molecular biology: similarities in DNA and protein sequences between species

Botany studies the characteristics, growth, and evolution of plants
Zoology investigates the structure, behavior, and evolution of animals
Microbiology examines the characteristics, growth, and interactions of microorganisms
Ecology explores the relationships between organisms and their environment

Cells are the basic structural and functional units of living organisms
The nucleus contains genetic material (DNA) and is surrounded by a double membrane
Mitochondria generate energy for the cell through cellular respiration
Ribosomes are responsible for protein synthesis, reading messenger RNA (mRNA) to build proteins
Lysosomes contain digestive enzymes that break down and recycle cellular waste and foreign substances
Photosynthesis converts light energy into chemical energy, producing glucose and oxygen
Respiration generates energy from glucose, producing ATP, water, and carbon dioxide

Mendelian Genetics explains how traits are inherited based on the principles of inheritance
The Law of Segregation states that each trait is determined by two alleles, one from each parent
The Law of Independent Assortment states that alleles for different traits are sorted independently
The Law of Dominance states that a dominant allele is expressed over a recessive allele
Autosomal dominant traits are expressed when one copy of the dominant allele is present
Autosomal recessive traits are expressed when two copies of the recessive allele are present
X-linked dominant traits are expressed when one copy of the dominant allele is present on the X chromosome
X-linked recessive traits are expressed when two copies of the recessive allele are present on the X chromosome
DNA is structured as a double helix, with sugar-phosphate molecules forming the backbone and nitrogenous bases forming the rungs
DNA replication involves unwinding the double helix, replicating each strand, and re-assembling the new DNA molecules
Gene expression involves transcribing DNA into messenger RNA (mRNA), translating mRNA into protein, and regulating the process to produce a functional product

The Theory of Evolution states that species change over time through natural selection, genetic drift, mutation, and gene flow
Mutation introduces random changes in DNA sequences, providing the raw material for evolution
Genetic drift involves random changes in allele frequency, often due to chance events or small population size
Gene flow occurs when individuals with different alleles migrate into a population, introducing new genetic variation
Natural selection favors individuals with advantageous traits, leading to their increased reproduction and survival
The fossil record shows a gradual sequence of changes in life forms over time
Comparative anatomy reveals similarities and homologies between different species
Molecular biology confirms similarities in DNA and protein sequences between species, indicating a common ancestry