Cell Biology and Genetics Overview

Cells: Basic unit of life, classified as prokaryotic (no nucleus) or eukaryotic (nucleus present).
Cell Organelles:
- Nucleus: Contains genetic material (DNA).
- Mitochondria: Powerhouse of the cell, site of ATP production.
- Ribosomes: Protein synthesis.
- Endoplasmic Reticulum:
  - Rough ER: Studded with ribosomes; protein synthesis and processing.
  - Smooth ER: Lipid synthesis and detoxification.
- Golgi Apparatus: Modifies, sorts, and packages proteins.
- Lysosomes: Digestive enzymes for waste processing.

DNA Structure: Double helix, composed of nucleotides (adenine, thymine, cytosine, guanine).
Gene Expression: Process by which information from a gene is used to synthesize proteins (transcription and translation).
Mendelian Genetics: Principles of inheritance established by Gregor Mendel.
- Dominant and Recessive Traits: Dominant alleles mask recessive alleles in phenotype.
- Punnett Squares: Tool for predicting genotype and phenotype ratios.

Ecosystems: Communities of living organisms interacting with their environment.
Biomes: Large ecological areas with distinct climates and species (e.g., tundra, rainforest).
Food Chains and Webs:
- Producers (plants) → Consumers (herbivores, carnivores) → Decomposers (fungi, bacteria).
Biodiversity: Variety of life in an ecosystem; important for resilience and stability.

Natural Selection: Mechanism of evolution where organisms better adapted to their environment tend to survive and reproduce.
Darwin’s Theory: Variation, competition, survival of the fittest, and adaptation lead to species evolution.
Speciation: Formation of new species through evolutionary processes (e.g., geographic isolation).

Homeostasis: Maintaining stable internal conditions (e.g., temperature, pH).
Organ Systems:
- Circulatory System: Transports nutrients and oxygen; includes heart and blood vessels.
- Respiratory System: Gas exchange; includes lungs and airways.
- Digestive System: Breaks down food into nutrients; includes stomach and intestines.
- Nervous System: Controls responses to stimuli; includes brain, spinal cord, and nerves.

Bacteria: Prokaryotic microorganisms; can be beneficial (gut flora) or pathogenic (causing diseases).
Viruses: Non-living entities that require a host cell to replicate.
Fungi: Eukaryotic organisms; can be decomposers or pathogens.

Photosynthesis: Process by which plants convert sunlight into energy (glucose) using chlorophyll.
Plant Structures:
- Roots: Absorb water and nutrients.
- Stems: Support and transport nutrients.
- Leaves: Primary site for photosynthesis.

Innate Behavior: Instinctive actions (e.g., reflexes).
Learned Behavior: Acquired through experience (e.g., conditioning).
Social Behavior: Interactions among individuals (e.g., mating rituals, pack behavior).

Macromolecules:
- Proteins: Made of amino acids; function as enzymes, structure, signaling.
- Carbohydrates: Sugars and starches; energy sources and structural components.
- Lipids: Fats and oils; energy storage and cellular membranes.
- Nucleic Acids: DNA and RNA; genetic information storage and transfer.

Cells are the basic unit of life, categorized into prokaryotic (lack a nucleus) and eukaryotic (contain a nucleus).
The nucleus houses genetic material, specifically DNA, crucial for cellular function and heredity.
Mitochondria are known as the cell's powerhouses, responsible for the production of ATP, a primary energy currency.
Ribosomes are essential for protein synthesis, assembling amino acids into polypeptides.
The Endoplasmic Reticulum (ER) has two types:
- Rough ER, which has ribosomes and is involved in protein synthesis and processing.
- Smooth ER, which synthesizes lipids and detoxifies harmful substances.
The Golgi Apparatus modifies, sorts, and packages proteins for secretion or use within the cell.
Lysosomes contain digestive enzymes necessary for breaking down waste materials.

DNA is structured as a double helix composed of nucleotides: adenine, thymine, cytosine, and guanine.
Gene expression involves transcription (copying DNA to RNA) and translation (synthesizing proteins from RNA).
Mendelian Genetics establishes fundamental principles of inheritance delineated by Gregor Mendel.
Dominant traits can overshadow recessive traits in phenotypes observed in offspring.
Punnett Squares serve as tools for predicting the genetic outcomes and ratios of offspring.

Ecosystems comprise communities of organisms interacting with their physical environment.
Biomes are expansive ecological regions characterized by specific climates and distinct species (e.g., tundra, rainforests).
Food chains highlight the flow of energy: Producers (plants) → Consumers (herbivores, carnivores) → Decomposers (fungi, bacteria).
Biodiversity indicates the variety of life within an ecosystem, contributing to stability and resilience against changes.

Natural Selection acts as a key evolutionary mechanism where organisms better suited to their environment have higher survival and reproductive rates.
Darwin’s Theory outlines key concepts of variation, competition, survival of the fittest, and adaptation leading to evolution.
Speciation refers to the evolutionary process resulting in the formation of new species, often through mechanisms such as geographic isolation.

Homeostasis is essential for organisms, allowing them to maintain stable internal environmental conditions like temperature and pH.
Organ systems include:
- Circulatory System: Transports nutrients and oxygen with components such as the heart and blood vessels.
- Respiratory System: Facilitates gas exchange through structures like the lungs and airways.
- Digestive System: Breaks down food into nutrients using organs like the stomach and intestines.
- Nervous System: Processes and responds to stimuli, involving the brain, spinal cord, and nerves.

Bacteria are prokaryotic microorganisms with diverse roles, as either beneficial (e.g., gut flora) or pathogenic (causing diseases).
Viruses lack cellular structure and depend on host cells for replication, categorizing them as non-living entities.
Fungi, as eukaryotic organisms, serve as decomposers or can act as pathogens affecting other organisms.

Photosynthesis enables plants to convert sunlight into chemical energy (glucose) with the help of chlorophyll.
Key plant structures include:
- Roots, responsible for nutrient and water absorption.
- Stems, which support the plant and facilitate nutrient transport.
- Leaves, acting as the primary site for photosynthesis processes.

Innate behaviors are instinctive and occur without prior experience, such as reflex actions.
Learned behaviors are acquired through experience and can involve processes like conditioning.
Social behaviors encompass interactions among individuals, including mating rituals and group dynamics (e.g., pack behavior).

Macromolecules include:
- Proteins, composed of amino acids, serving various roles, including enzymes and structural components.
- Carbohydrates, consisting of sugars and starches, function as energy sources and structural units.
- Lipids, including fats and oils, function in energy storage and forming cellular membranes.
- Nucleic Acids (DNA and RNA) store and transfer genetic information critical for heredity and cell function.