Cell Biology and Genetics Overview

Cell Theory
- All living organisms are composed of cells.
- The cell is the basic unit of life.
- All cells arise from pre-existing cells.
Cell Structure
- Prokaryotic Cells: Lack nucleus, smaller, simpler (e.g., bacteria).
- Eukaryotic Cells: Have a nucleus, larger, complex (e.g., plant and animal cells).
Organelles
- Nucleus: Contains DNA, controls cell activities.
- Mitochondria: Powerhouse, site of ATP production.
- Ribosomes: Protein synthesis.
- Endoplasmic Reticulum: Synthesis of proteins (Rough ER) and lipids (Smooth ER).
- Golgi Apparatus: Modifies and packages proteins.
- Lysosomes: Digestion of waste materials.

DNA Structure
- Double helix composed of nucleotides (adenine, thymine, cytosine, guanine).
- Base pairing: A-T and C-G.
Gene Expression
- Transcription: DNA to mRNA.
- Translation: mRNA to protein.
Mendelian Genetics
- Law of Segregation: Alleles separate during gamete formation.
- Law of Independent Assortment: Alleles for different traits are passed independently.

Ecosystem Components
- Biotic Factors: Living organisms interacting within an ecosystem.
- Abiotic Factors: Non-living elements (temperature, water, soil).
Energy Flow
- Solar energy → producers (plants) → consumers (herbivores, carnivores) → decomposers.
Biomes
- Different ecological regions classified by climate and vegetation (e.g., desert, rainforest, tundra).

Natural Selection
- Organisms better adapted to their environment tend to survive and reproduce.
- Key concepts: Variation, inheritance, selection.
Speciation
- Formation of new species through evolutionary processes (e.g., geographic isolation, reproductive isolation).

Homeostasis
- Maintenance of stable internal conditions (e.g., temperature regulation).
Organ Systems
- Circulatory System: Transports nutrients, gases, hormones.
- Respiratory System: Facilitates gas exchange.
- Nervous System: Controls responses to stimuli.
- Endocrine System: Hormonal regulation of processes.

Types of Microorganisms
- Bacteria: Prokaryotic, diverse metabolisms, important in decomposition and nitrogen fixation.
- Viruses: Non-cellular, require a host to replicate.
- Fungi: Eukaryotic, decomposers, some pathogenic.
Infectious Diseases
- Caused by pathogens (bacteria, viruses, fungi).
- Transmission methods: contact, airborne, vector-borne.

Applications
- Genetic engineering (e.g., CRISPR).
- Biopharmaceuticals (production of drugs using biological systems).
- Conservation (gene banks for endangered species).

All life is made up of building blocks called cells, these are the simplest unit of life
Cells can only be created from other, pre-existing cells

There are two main types of cells: prokaryotic and eukaryotic.
Prokaryotic cells are small and simple, without a nucleus, e.g., bacteria
Eukaryotic cells are larger and more complex, with a nucleus, e.g., animal and plant cells.

Nucleus: Contains DNA, which is the "instruction manual" for the cell.
Mitochondria: This organelle is responsible for generating energy in the form of ATP, hence it is often called the powerhouse of the cell.
Ribosomes: These small organelles synthesize proteins, the building blocks of cells and the enzymes that drive chemical reactions.
Endoplasmic Reticulum (ER): There are two forms:
- Rough ER: studded with ribosomes, it is involved in protein synthesis.
- Smooth ER: lacks ribosomes and is involved in lipid synthesis and detoxification.
Golgi Apparatus: This organelle packages and modifies proteins for secretion or use within the cell.
Lysosomes: These are like the cell's "recycling center," they break down waste materials and cellular debris.

DNA is a double helix, with each strand made up of nucleotides, which are sugar molecules that contain one of four nitrogenous bases: adenine (A), thymine (T), cytosine (C), and guanine (G).
The two strands of DNA are held together by hydrogen bonds between the complementary base pairs: Adenine always pairs with Thymine (A-T), and Cytosine always pairs with Guanine (C-G).

Transcription: This process converts DNA into messenger RNA (mRNA), which carries the genetic information from the nucleus to the ribosomes.
Translation: This process uses the mRNA to assemble amino acids into proteins.

Law of Segregation: An organism inherits two alleles for each trait, one from each parent. These alleles separate during gamete (sperm and egg) formation, so each gamete receives only one allele.
Law of Independent Assortment: Alleles for different traits are inherited independently of each other, meaning that the inheritance of one trait does not influence the inheritance of another.

Biotic factors: These include all the living organisms in an ecosystem, such as plants, animals, fungi, and bacteria.
Abiotic factors: These are the non-living components of an ecosystem, including temperature, water, sunlight, and soil.

The flow of energy through an ecosystem begins with the sun, where it is captured by producers, such as plants.
Producers are eaten by consumers, such as herbivores (plant-eaters) and carnivores (meat-eaters).
Decomposers, like fungi and bacteria, break down dead organisms and waste, returning nutrients to the ecosystem.

Biomes are large-scale ecosystems that are characterized by their climate and vegetation.
Examples of biomes include deserts, rainforests, tundras, grasslands, and forests.

Natural selection is the process by which organisms with traits that make them better suited to their environment are more likely to survive and reproduce.
This process requires variation in traits, inheritance of those traits, and selection pressure from the environment.

Speciation is the process by which new species arise from existing ones.
This can occur through mechanisms such as geographic isolation (physical separation of populations) or reproductive isolation (inability of populations to interbreed).

Homeostasis is the process of maintaining a stable internal environment in an organism.
It is essential for survival, as it ensures that cells can function properly.

The human body is made up of multiple organ systems, each with a specialized function.
Circulatory system: Transports nutrients, oxygen, and waste products throughout the body.
Respiratory system: Enables gas exchange (oxygen uptake and carbon dioxide elimination).
Nervous system: Coordinates and regulates responses to stimuli.
Endocrine system: Secretes hormones that regulate various bodily functions, such as growth and metabolism.

Bacteria: These are single-celled prokaryotes, with a diverse range of metabolic capabilities.
Viruses: These are non-cellular entities that can reproduce only inside a host cell.
Fungi: These are eukaryotic organisms, mostly multicellular, that act as decomposers and some are pathogenic.

Infectious diseases are caused by pathogens, such as bacteria, viruses, fungi, and parasites.
Pathogens can be transmitted through various methods, including contact, airborne, and vector-borne transmission.

This field uses biological systems and organisms for technological applications.
Genetic engineering: This involves manipulating genes to modify organisms or produce specific products.
Biopharmaceuticals: This uses biological systems to produce drugs, such as insulin.
Conservation: Involves using biotechnology to preserve endangered species.