Biology: Cell, Genetics, and Evolution

Cell Structure
- Prokaryotic vs. Eukaryotic cells
- Organelles: nucleus, mitochondria, endoplasmic reticulum, Golgi apparatus, lysosomes
- Cell membrane: phospholipid bilayer, function and permeability
Cell Division
- Mitosis: phases (prophase, metaphase, anaphase, telophase), cytokinesis
- Meiosis: stages, importance for sexual reproduction, genetic variation

DNA Structure
- Double helix model, nucleotide components (sugar, phosphate, base)
- Base pairing: adenine-thymine, cytosine-guanine
Gene Expression
- Transcription: DNA to mRNA
- Translation: mRNA to protein
- Role of RNA types: mRNA, tRNA, rRNA
Mendelian Genetics
- Principles of segregation and independent assortment
- Dominant and recessive alleles, genotype vs. phenotype

Natural Selection
- Mechanism of evolution proposed by Darwin
- Variations in traits, survival of the fittest, adaptation
Speciation
- Allopatric vs. sympatric speciation
- Role of genetic drift and gene flow

Ecosystems
- Components: biotic (living) and abiotic (non-living)
- Food chains and food webs, trophic levels
Biomes
- Major types: tundra, desert, forest, grassland, aquatic
- Climate and organisms characteristic of each biome

Body Systems
- Major systems: circulatory, respiratory, digestive, nervous, endocrine, immune
- Functions and interactions among systems
Homeostasis
- Mechanisms to maintain internal balance (temperature, pH, glucose levels)
- Feedback loops: negative vs. positive feedback

Genetic Engineering
- Techniques: CRISPR, recombinant DNA
- Applications: agriculture, medicine, forensic science
Cloning
- Types: therapeutic vs. reproductive cloning
- Ethical considerations and potential uses

Bacteria and Viruses
- Structure and classification of bacteria
- Viral replication cycles: lytic and lysogenic cycles
Importance of Microorganisms
- Roles in ecosystems, human health, and industry (fermentation, bioremediation)

Prokaryotic cells lack a nucleus and are generally smaller; eukaryotic cells have a nucleus and are larger, featuring complex organelles.
Key organelles include the nucleus (holds genetic material), mitochondria (energy production), endoplasmic reticulum (protein and lipid synthesis), Golgi apparatus (packaging and distribution), and lysosomes (waste breakdown).
The cell membrane is a phospholipid bilayer that controls permeability and communication between the cell and its environment.

Mitosis consists of prophase, metaphase, anaphase, and telophase, culminating in cytokinesis, dividing one cell into two identical daughter cells.
Meiosis involves two rounds of division, creating four genetically varied gametes, essential for sexual reproduction and increasing genetic diversity.

DNA is structured as a double helix; nucleotides consist of a sugar, a phosphate group, and a nitrogenous base.
Base pairing rules dictate that adenine pairs with thymine and cytosine pairs with guanine, maintaining the integrity of genetic information.

Transcription converts DNA sequences into mRNA, which carries the genetic code outside the nucleus.
Translation translates the mRNA code into a specific protein with the aid of tRNA, which brings amino acids, and rRNA, which makes up the ribosome.

Mendel's principles include segregation (alleles separate during gamete formation) and independent assortment (genes for different traits are inherited independently).
Dominant alleles mask recessive alleles, determining phenotype, which is the observable characteristic influenced by genotype, the genetic makeup.

Natural selection, proposed by Darwin, is the process where organisms with favorable traits survive and reproduce, driving evolutionary change.
Speciation occurs when populations evolve into distinct species; allopatric speciation happens due to geographic separation, while sympatric speciation occurs within the same environment. Genetic drift and gene flow also influence speciation.

Ecosystems are made of biotic (living) and abiotic (non-living) components, working together in food chains and webs that illustrate energy flow and trophic levels.
Major biomes include tundra, desert, forest, grasslands, and aquatic; each biome has distinct climate and organisms adapted to its conditions.

The human body consists of several major systems, including circulatory (transporting blood), respiratory (gas exchange), digestive (nutrient processing), nervous (signal transmission), endocrine (hormone regulation), and immune (defense against pathogens).
Homeostasis is the maintenance of stable internal conditions through mechanisms like temperature regulation and feedback loops, which can be negative (stabilizing) or positive (amplifying changes).

Genetic engineering techniques such as CRISPR and recombinant DNA allow manipulation of genetic material for various applications in agriculture, medicine, and forensic science.
Cloning can be therapeutic (cell replacement) or reproductive (creating genetically identical organisms), with ethical considerations concerning the implications and uses of cloned beings.

Bacteria are classified based on structure (shape, cell wall), and consist of diverse metabolic pathways; viruses replicate through lytic (destructive) or lysogenic (integrative) cycles.
Microorganisms play crucial roles in ecosystems, contributing to human health (gut flora) and industries through processes such as fermentation and bioremediation.