Biology: Cell Theory and Genetics Overview

Cell Biology

• Cell Theory

  • All living organisms are composed of cells.
  • Cells are the basic unit of life.
  • All cells arise from pre-existing cells.

• Cell Structure

  • Prokaryotic Cells: Lack a nucleus, smaller, include bacteria.
  • Eukaryotic Cells: Have a nucleus, larger, include plants, animals, fungi.
  • Organelles: Specialized structures (e.g., mitochondria, ribosomes, endoplasmic reticulum).

Genetics

• DNA Structure

  • Double helix composed of nucleotides (adenine, thymine, cytosine, guanine).

• Genes and Alleles

  • Genes: Segments of DNA that code for proteins.
  • Alleles: Different forms of a gene.

• Mendelian Inheritance

  • Laws of Segregation and Independent Assortment.
  • Phenotype vs. Genotype: Observable traits vs. genetic makeup.

Evolution

• Natural Selection

  • Mechanism of evolution where organisms better adapted to their environment tend to survive and reproduce.

• Speciation

  • Process by which new species arise.
  • Can occur through allopatric (geographic isolation) or sympatric (same area, reproductive isolation) mechanisms.

Human Biology

• Body Systems
  • Circulatory: Transports blood and nutrients.
  • Respiratory: Gas exchange (oxygen in, CO2 out).
  • Digestive: Breaks down food for energy.
  • Nervous: Processes information through the brain and nerves.
  • Endocrine: Regulates bodily functions via hormones.

Ecology

• Ecosystems

  • Communities of living organisms and their physical environment.
  • Energy flow: Sunlight -> Producers (plants) -> Consumers (herbivores, carnivores) -> Decomposers.

• Biomes

  • Large ecological areas (e.g., forests, deserts, grasslands).
  • Characterized by climate, vegetation, and animal life.

Plant Biology

• Photosynthesis

  • Process by which plants convert light energy into chemical energy (glucose).
  • Occurs in chloroplasts using sunlight, water, and CO2.

• Plant Structure

  • Roots: Absorb water and nutrients.
  • Stems: Support and transport.
  • Leaves: Main site of photosynthesis.

Microbiology

• Bacteria

  • Single-celled organisms, can be beneficial or pathogenic.

• Viruses

  • Non-cellular, require a host to replicate, can cause diseases.

Biotechnology

• Genetic Engineering

  • Manipulation of an organism's DNA to alter its traits.
  • Applications: GMOs, gene therapy.

• CRISPR Technology

  • Tool for editing genomes with precision.
  • Allows for targeted modifications in DNA sequences.

Research Techniques

• Microscopy

  • Light and electron microscopy for observing cells and tissues.

• PCR (Polymerase Chain Reaction)

  • Technique to amplify specific DNA segments for analysis.

• Gel Electrophoresis

  • Method for separating DNA fragments based on size.

Evolutionary Biology

• Darwin's Theory

  • Focused on adaptation and survival of the fittest.

• Modern Synthesis

  • Integrates Mendelian genetics with evolutionary theory.

Bioethics

• Considerations
  • Implications of biotechnological advances on society.
  • Ethical challenges in genetic engineering and cloning.

Cell Theory

• All living things are made up of cells.
• Cells are the basic unit of life.
• New cells come from pre-existing cells.

Cell Structure

• Prokaryotic Cells: Simpler, smaller, have no nucleus (e.g., bacteria).
• Eukaryotic Cells: More complex, larger, have a nucleus (e.g., plants, animals, fungi).
• Organelles: Specialized structures within cells that perform specific functions (e.g., mitochondria, ribosomes, endoplasmic reticulum).

DNA Structure

• DNA consists of two strands forming a double helix.
• Each strand is made up of nucleotides: adenine (A), thymine (T), cytosine (C), and guanine (G).
• A always pairs with T, and C always pairs with G.

Genes and Alleles

• Genes: Sections of DNA that provide instructions for making proteins.
• Alleles: Different versions of a gene.

Mendelian Inheritance

• Laws of Segregation: Each parent contributes one allele for a trait to their offspring.
• Laws of Independent Assortment: Alleles for different traits are inherited independently of each other.
• Phenotype: Observable traits.
• Genotype: Genetic makeup.

Natural Selection

• Organisms with traits better suited to their environment have a higher chance of survival and reproduction.
• Over time, this leads to changes in the population as beneficial traits become more common.

Speciation

• The process of forming new species.
• Allopatric speciation: Occurs when populations are geographically isolated.
• Sympatric speciation: Occurs when populations in the same area become reproductively isolated.

Body Systems

• Circulatory System: Transports blood, oxygen, nutrients, and removes waste products.
• Respiratory System: Facilitates gas exchange (oxygen in, carbon dioxide out).
• Digestive System: Breaks down food into nutrients for the body to absorb.
• Nervous System: Controls and coordinates bodily functions through brain, spinal cord, and nerves.
• Endocrine System: Produces and releases hormones to regulate bodily functions.

Ecosystems

• A community of living organisms interacting with their physical environment.
• Energy Flow: The transfer of energy from the sun to producers (plants), then consumers (animals), and finally decomposers.

Biomes

• Large geographic areas with similar climate, vegetation, and animal life.
• Examples include forests, deserts, grasslands, and tundra.

Photosynthesis

• Process by which plants convert light energy into chemical energy (glucose).
• Occurs in chloroplasts using sunlight, water, and carbon dioxide.

Plant Structure

• Roots: Absorb water and nutrients from the soil.
• Stems: Provide support and transport water and nutrients throughout the plant.
• Leaves: Main site of photosynthesis.

Bacteria

• Single-celled organisms (prokaryotes) with diverse roles.
• Can be beneficial (e.g., decomposing organic matter) or pathogenic (causing disease).

Viruses

• Non-cellular entities that require a host to replicate.
• They can cause diseases by hijacking a host cell's machinery to make copies of themselves.

Genetic Engineering

• Manipulation of an organism's DNA to alter its traits.
• GMOs (Genetically Modified Organisms): Organisms with altered DNA for specific purposes.
• Gene Therapy: Using genes to treat or prevent diseases.

CRISPR Technology

• Precise tool for editing genomes.
• Allows for targeted modifications of DNA sequences.

Microscopy

• Light Microscopy: Uses visible light to view cells and tissues.
• Electron Microscopy: Uses a beam of electrons to magnify objects at much higher resolution.

PCR (Polymerase Chain Reaction)

• Technique for amplifying specific DNA segments for research and analysis.

Gel Electrophoresis

• Method used to separate DNA fragments based on their size and charge.

Darwin's Theory

• Evolution occurs through natural selection, favoring organisms better adapted to their environment.

Modern Synthesis

• Integration of Mendelian genetics with Darwin's theory.
• Explains how genetic variation contributes to the evolution of populations.

Bioethics

• Examines the ethical implications of biotechnology on society.
• Considers ethical challenges arising from genetic engineering, cloning, and other advancements.

Test your understanding of fundamental biological concepts including cell theory, cell structure, DNA structure, and genetic inheritance. This quiz covers essential topics in cell biology and genetics, emphasizing the principles of evolution and natural selection.