Cell Biology and Genetics Overview

Cell Structure:
- Prokaryotic vs. Eukaryotic cells
  - Prokaryotic: No nucleus, smaller, unicellular (e.g., bacteria)
  - Eukaryotic: Nucleus present, larger, unicellular or multicellular (e.g., plants, animals)
- Organelles and their functions:
  - Nucleus: Stores genetic material
  - Mitochondria: Powerhouse of the cell, energy production
  - Ribosomes: Protein synthesis
  - Endoplasmic Reticulum (ER): Protein and lipid synthesis
  - Golgi Apparatus: Packaging and transport of proteins
  - Cell Membrane: Selective barrier, regulates entry and exit
Cell Division:
- Mitosis: Somatic cell division, results in two identical daughter cells
- Meiosis: Gamete formation, results in four genetically diverse daughter cells

Fundamental Concepts:
- Genes: Basic units of heredity, made of DNA
- Alleles: Different versions of a gene
- Genotype vs. Phenotype:
  - Genotype: Genetic makeup
  - Phenotype: Expressed traits
- Mendelian inheritance: Principles of dominance, segregation, and independent assortment
DNA Structure and Replication:
- Double helix model, composed of nucleotides (A, T, C, G)
- Replication process: Semi-conservative, involves enzymes like DNA polymerase
Genetic Variation:
- Mutations: Changes in DNA sequence
- Crossing over during meiosis leads to genetic diversity

Ecosystem Components:
- Biotic factors: Living organisms (plants, animals, microbes)
- Abiotic factors: Non-living elements (water, soil, climate)
Energy Flow and Nutrient Cycling:
- Food chains and food webs: Flow of energy from producers to consumers
- Trophic levels: Producers, primary consumers, secondary consumers, decomposers
Population Dynamics:
- Factors affecting population size: Birth rate, death rate, immigration, emigration
- Carrying capacity: Maximum population size an environment can sustain

Theory of Evolution:
- Natural selection: Mechanism proposed by Charles Darwin
  - Survival of the fittest: Better-adapted individuals survive and reproduce
- Speciation: Formation of new and distinct species
- Common descent: All living organisms share a common ancestor
Evidence of Evolution:
- Fossil records: Show changes in species over time
- Comparative anatomy: Homologous structures indicate common ancestry
- Molecular biology: Similarities in DNA and protein sequences

Microorganisms:
- Types: Bacteria, viruses, fungi, protozoa, algae
- Bacteria: Prokaryotic, diverse metabolic pathways, can be pathogenic or beneficial
Pathogenic Microorganisms:
- Infectious diseases caused by bacteria and viruses
- Transmission methods: Direct contact, airborne, vector-borne
Microbial Ecology:
- Role in ecosystems: Decomposition, nutrient cycling, symbiotic relationships
- Importance in biotechnology: Use in fermentation, antibiotic production, and genetic engineering

Prokaryotic cells lack a nucleus, are smaller, and primarily unicellular, with bacteria as a notable example.
Eukaryotic cells have a nucleus, are larger, and can be either unicellular or multicellular, represented by plants and animals.
The nucleus stores genetic material, crucial for heredity.
Mitochondria are known as the cell's powerhouse, responsible for energy production through aerobic respiration.
Ribosomes are the sites for protein synthesis, translating genetic information into proteins.
The Endoplasmic Reticulum (ER) synthesizes proteins and lipids, playing a vital role in cellular function.
The Golgi Apparatus packages and transports proteins to their destinations within or outside the cell.
The cell membrane acts as a selective barrier, controlling the entry and exit of substances.

Mitosis is a process of somatic cell division, yielding two genetically identical daughter cells essential for growth and repair.
Meiosis produces gametes and results in four genetically diverse daughter cells, contributing to genetic variation.

Genes are the fundamental units of heredity composed of DNA and determine traits.
Alleles are different variations of a gene, affecting the trait's expression.
Genotype refers to an organism's genetic makeup, while phenotype is the observable expression of traits.
Mendelian inheritance includes principles such as dominance (one allele masks another), segregation (alleles separate during gamete formation), and independent assortment (genes for different traits segregate independently).

DNA is structured as a double helix, made up of nucleotide bases: adenine (A), thymine (T), cytosine (C), and guanine (G).
DNA replication is semi-conservative and involves enzymes like DNA polymerase, ensuring accurate duplication of genetic information.

Mutations are changes in the DNA sequence that can lead to new traits or genetic diversity within a population.
Crossing over during meiosis provides genetic diversity by exchanging genetic material between homologous chromosomes.

Ecosystems consist of biotic factors like living organisms and abiotic factors such as non-living elements (water, soil, climate).
Energy flows through ecosystems via food chains and food webs, connecting producers, consumers, and decomposers.
Trophic levels categorize organisms based on their role in energy transfer, including producers (photosynthetic organisms), primary consumers (herbivores), secondary consumers (carnivores), and decomposers (detritivores).

Population size is influenced by birth and death rates, immigration, and emigration.
Carrying capacity refers to the maximum population size that an environment can sustainably support.

Natural selection, introduced by Charles Darwin, is the process by which individuals better adapted to their environment tend to survive and reproduce, enabling evolution.
Speciation is the formation of new species due to evolutionary processes.
Common descent suggests all living organisms share a common ancestor, explaining the diversity of life.

Fossil records provide insights into evolutionary changes and the history of species.
Comparative anatomy shows homologous structures that indicate common ancestry among different organisms.
Molecular biology reveals similarities in DNA and protein sequences, supporting evolutionary relationships among species.

Microorganisms include bacteria, viruses, fungi, protozoa, and algae, each with unique characteristics.
Bacteria are prokaryotic organisms with diverse metabolic pathways, sometimes causing diseases or providing beneficial functions.

Infectious diseases can be caused by bacteria and viruses, with transmission occurring through direct contact, airborne particles, or vectors (e.g., insects).

Microorganisms play essential roles in ecosystems, including decomposition, nutrient cycling, and forming symbiotic relationships with other organisms.
Microbes are pivotal in biotechnology for applications such as fermentation processes, antibiotic production, and advancements in genetic engineering.