Biology Branches and Cell Structure

Cells are the basic units of life
Cell structure:
- Plasma membrane: outer layer of cell
- Cytoplasm: jelly-like substance inside cell
- Nucleus: contains genetic material (DNA)
- Mitochondria: generate energy for cell
Cell functions:
- Metabolism: chemical reactions that occur within cell
- Photosynthesis: process by which plants produce energy
- Cell division: process by which cells reproduce

Heredity: passing of traits from parents to offspring
DNA (deoxyribonucleic acid):
- Double helix structure
- Contains genetic information
Genes: segments of DNA that code for specific traits
Traits:
- Dominant: trait that will be expressed if present
- Recessive: trait that will not be expressed if dominant trait is present
Inheritance patterns:
- Mendelian inheritance: follows predictable patterns
- Non-Mendelian inheritance: does not follow predictable patterns

Theory of evolution: species change over time through natural selection
Natural selection:
- Process by which individuals with favorable traits are more likely to survive and reproduce
- Leads to adaptation and speciation
Types of evolution:
- Microevolution: small-scale changes within a population
- Macroevolution: large-scale changes between species
Evidence for evolution:
- Fossil record
- Comparative anatomy
- Molecular biology

Ecosystem: community of living and non-living things in an environment
Biotic factors:
- Producers: organisms that make their own food (plants)
- Consumers: organisms that obtain energy by consuming other organisms
- Decomposers: organisms that break down dead organic matter
Abiotic factors:
- Light
- Temperature
- Water
- Soil
Energy flow:
- Producers convert sunlight into energy
- Energy is passed from one organism to another through food chains and webs

Botany: Focuses on the study of plants and their processes.
Zoology: Investigates animal life and behavior.
Microbiology: Examines microorganisms, including bacteria and viruses.
Ecology: Studies how organisms interact with each other and their environments.
Genetics: Explores heredity and variations among organisms.
Biochemistry: Analyzes chemical processes and substances within living beings.
Biophysics: Applies principles of physics to understand biological functions.

Basic Unit of Life: Cells are fundamental structures that make up all living organisms.
Cell Structure:
- Plasma Membrane: Encloses the cell, providing protection and structural support.
- Cytoplasm: Gel-like fluid where cellular components are suspended.
- Nucleus: Houses DNA, the hereditary material.
- Mitochondria: Energy-producing organelles, termed the "powerhouses" of the cell.
Cell Functions:
- Metabolism: Encompasses all biochemical reactions essential for maintaining life.
- Photosynthesis: Converts light energy into chemical energy in plants.
- Cell Division: Mechanism through which cells replicate to support growth and repair.

Heredity: The process by which traits are transmitted from parents to offspring.
DNA Structure: Composed of two intertwined strands forming a double helix that contains genetic blueprints.
Genes: Specific sequences within DNA that dictate particular traits or characteristics.
Traits:
- Dominant Traits: Will manifest in the phenotype if present.
- Recessive Traits: Only expressed when paired with another recessive gene.
Inheritance Patterns:
- Mendelian Inheritance: Governed by predictable ratios and genetic segregation.
- Non-Mendelian Inheritance: Characterized by more complex patterns, including incomplete dominance and polygenic traits.

Theory of Evolution: Proposes that species evolve over time through processes like natural selection.
Natural Selection:
- A mechanism where individuals with advantageous traits have higher survival and reproduction rates.
- Drives adaptations and contributes to the creation of new species (speciation).
Types of Evolution:
- Microevolution: Subtle changes occurring within a population over generations.
- Macroevolution: Extensive alterations granting rise to new species.
Evidence for Evolution:
- Fossil Record: Provides historical documentation of organism transitions.
- Comparative Anatomy: Studies structural similarities across different species.
- Molecular Biology: Examines genetic material, revealing shared ancestry among diverse organisms.

Ecosystem Definition: Comprises living (biotic) and non-living (abiotic) components interacting in a specific environment.
Biotic Factors:
- Producers: Autotrophs (primarily plants) that synthesize their own food using photosynthesis.
- Consumers: Heterotrophs that derive energy by consuming other organisms.
- Decomposers: Organisms, like fungi and bacteria, that recycle nutrients by breaking down dead matter.
Abiotic Factors:
- Light: Essential for photosynthesis.
- Temperature: Influences metabolic rates of organisms.
- Water: Vital for all forms of life.
- Soil: Provides nutrients and habitat for organisms.
Energy Flow:
- Initiated by producers capturing sunlight and translating it to energy, which is then transferred through food chains and webs to consumers.