Cell Biology and Genetics Overview

Cell Biology

Basic Unit of Life: Cells are the smallest structural and functional unit of living organisms.
Cell Structure:
- Prokaryotic Cells: No nucleus, smaller, single-celled (e.g., bacteria).
- Eukaryotic Cells: Nucleus present, larger, can be single-celled or multicellular (e.g., plants, animals).
Cell Organelles:
- Nucleus: Contains genetic material.
- Mitochondria: Powerhouse of the cell, site of ATP production.
- Ribosomes: Protein synthesis.
- Endoplasmic Reticulum: Protein and lipid synthesis (rough and smooth).
- Golgi Apparatus: Modifies, sorts, and packages proteins and lipids.
- Cell Membrane: Semi-permeable barrier.

Genetics

DNA Structure: Double helix, composed of nucleotides (A, T, 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: Genes for different traits segregate independently.
Mutations: Changes in DNA sequence can lead to variations.

Evolutionary Biology

Theory of Evolution: Change in heritable traits over generations.
Natural Selection: Survival and reproduction of organisms best adapted to their environment.
Speciation: Formation of new species through processes like geographic isolation.
Evidence of Evolution:
- Fossil records
- Comparative anatomy
- Molecular biology (DNA sequence comparisons)

Ecology

Ecosystem: Community of living organisms interacting with their physical environment.
Biomes: Large ecological areas with distinct climates and ecosystems (e.g., tundra, rainforest).
Trophic Levels:
- Producers (autotrophs)
- Consumers (herbivores, carnivores, omnivores)
- Decomposers (detritivores)
Biogeochemical Cycles: Cycles of matter (e.g., water, carbon, nitrogen) through ecosystems.

Microbiology

Microorganisms: Include bacteria, viruses, fungi, protozoa, and algae.
Bacterial Classification:
- Shape (bacilli, cocci, spirilla)
- Gram-staining (positive vs. negative)
Viruses: Non-cellular, require a host to reproduce.
Fungi: Decomposers, can be unicellular (yeasts) or multicellular (molds).

Physiology

Homeostasis: Maintenance of stable internal conditions (e.g., temperature, pH).
Organ Systems:
- Circulatory (transport of nutrients and oxygen)
- Respiratory (gas exchange)
- Digestive (food processing and nutrient absorption)
- Nervous (control and communication)
Hormonal Regulation: Endocrine system regulates physiological processes through hormones.

Zoology

Animal Kingdom Classification: Based on characteristics such as symmetry, tissue organization, and development.
Major Phyla:
- Arthropoda (insects, crustaceans)
- Chordata (vertebrates)
- Mollusca (snails, octopuses)
Animal Behavior: Study of how animals interact with each other and their environment.

Anatomy

Gross Anatomy: Study of structures that can be seen with the naked eye (e.g., organs).
Microscopic Anatomy: Study of structures at the cellular level (e.g., histology).
Organ Systems: Group of organs working together for specific functions.

Morphology

Study of Form and Structure: Examines the shape, size, and structure of organisms.
Plant Morphology: Study of plant structures including roots, stems, leaves, and flowers.
Animal Morphology: Focus on anatomical features such as skeletal structures and organ placements.
Adaptations: Morphological traits that enhance survival in specific environments.

Cell Biology

Cell Theory: The fundamental unit of life is the cell. All living organisms are composed of one or more cells.
Prokaryotic Cells: Lack a membrane-bound nucleus, smaller in size, and are typically single-celled organisms.
Eukaryotic Cells: Contain a nucleus, larger in size, and can be single-celled or multicellular organisms like plants and animals.
Nucleus: The control center, contains DNA, the blueprint for the cell's functions.
Mitochondria: The powerhouse, responsible for generating energy (ATP) through cellular respiration.
Ribosomes: Sites of protein synthesis, translating genetic information into proteins.
Endoplasmic Reticulum: A network of membranes involved in protein and lipid synthesis (rough ER) and detoxification (smooth ER).
Golgi Apparatus: Packages, modifies, and sorts proteins and lipids for transport within or outside the cell.
Cell Membrane: A selectively permeable barrier that regulates what enters and exits the cell.

Genetics

DNA: A double helix structure, composed of nucleotides (adenine, thymine, cytosine, guanine) that carry genetic information.
Gene expression: The process of converting genetic information into functional products (proteins).
Transcription: DNA is transcribed into messenger RNA (mRNA).
Translation: mRNA is translated into a protein by ribosomes.
Mendelian Genetics: Principles of inheritance that describe how traits are passed from parents to offspring.
Law of Segregation: Alleles for a specific trait separate during gamete formation, so each gamete receives only one allele.
Law of Independent Assortment: Genes for different traits segregate independently during gamete formation, meaning inherited traits are not linked.
Mutations: Changes in DNA sequence that can lead to genetic variations, some beneficial and some harmful.

Evolutionary Biology

Theory of Evolution: The process of change in heritable traits within a population over generations.
Natural Selection: A mechanism driving evolution, where organisms with beneficial traits are more likely to survive and reproduce, passing those traits to their offspring.
Speciation: The evolutionary process by which new species arise from existing ones, often through isolation and adaptation.
Evidence of Evolution:
- Fossil Records: Show changes in organisms over time, documenting the evolution of life.
- Comparative Anatomy: Examining similarities and differences in body structures of different species, revealing evolutionary relationships.
- Molecular Biology: Comparing DNA sequences to determine evolutionary relationships based on genetic similarities.

Ecology

Ecosystem: A community of living organisms interacting with their non-living environment.
Biomes: Large-scale ecological areas with distinct climates and associated plant and animal communities (e.g., tundra, rainforest, desert).
Trophic Levels: Levels within a food chain or web, showing the flow of energy:
- Producers: Autotrophs that make their own food through photosynthesis (e.g., plants).
- Consumers: Heterotrophs that obtain energy by consuming other organisms (e.g., herbivores, carnivores, omnivores).
- Decomposers: Break down dead organic matter, recycling nutrients back into the ecosystem (e.g., bacteria, fungi).
Biogeochemical Cycles: The cyclical movement of matter (e.g., water, carbon, nitrogen) through living organisms and their environment.

Microbiology

Microorganisms: Tiny living organisms, including bacteria, viruses, fungi, protozoa, and algae.
Bacterial Classification:
- Shape: Bacilli (rod-shaped), cocci (round), spirilla (spiral).
- Gram Staining: A method used to differentiate bacteria based on their cell wall structure (gram-positive vs. gram-negative).
Viruses: Non-living entities that require a host cell to reproduce.
Fungi: Decomposers that can be single-celled (e.g., yeasts) or multicellular (e.g., molds).

Physiology

Homeostasis: Maintaining a stable internal environment despite external changes (e.g., regulating temperature, pH).
Organ Systems: Groups of organs working together to perform specific functions:
- Circulatory System: Transports nutrients, oxygen, and waste throughout the body.
- Respiratory System: Responsible for gas exchange (taking in oxygen and releasing carbon dioxide).
- Digestive System: Breaks down food and absorbs nutrients.
- Nervous System: Controls and coordinates body functions through communication using nerve signals.
Hormonal Regulation: The endocrine system uses hormones to regulate a wide range of physiological processes.

Zoology

Animal Kingdom Classification: Classifying animals based on characteristics like symmetry, tissue organization, and embryonic development.
Major Phyla:
- Arthropoda: The largest phylum, including insects, crustaceans, arachnids, and myriapods.
- Chordata: Animals with a notochord, dorsal hollow nerve cord, and pharyngeal slits at some point in development, including vertebrates.
- Mollusca: Soft-bodied animals often with hard shells, including snails, slugs, clams, and octopuses.
Animal Behavior: The study of how animals interact with each other and their environment.

Anatomy

Gross Anatomy: The study of body structures that can be seen with the naked eye, such as organs and organ systems.
Microscopic Anatomy: The study of structures at the cellular level, including tissues and cells.
Organ Systems: Groups of organs working together to perform a specific function (e.g., digestive system, respiratory system).

Morphology

Study of Form and Structure: Examines the shape, size, and structure of organisms.
Plant Morphology: Focuses on the structures of plants, including roots, stems, leaves, and flowers.
Animal Morphology: Examines the anatomical features of animals, including skeletal structures, organ placements, and external features.
Adaptations: Features that are shaped by natural selection, enhancing an organism's chances of survival and reproduction in a specific environment.