Biology Chapter: Cell Structure and Genetics

Cell Structure and Function

• Prokaryotic Cells:

  • Lack a nucleus and membrane-bound organelles.
  • DNA is circular and located in the nucleoid region.
  • Examples: Bacteria and Archaea.

• Eukaryotic Cells:

  • Have a nucleus and membrane-bound organelles.
  • DNA is linear and associated with histones.
  • Examples: Plant cells, animal cells, fungi, protists.

Genetics

• DNA Structure:

  • Double helix composed of nucleotides (adenine, thymine, cytosine, guanine).
  • Base pairing: A-T, C-G.

• Mendelian Genetics:

  • Law of Segregation: Alleles separate during gamete formation.
  • Law of Independent Assortment: Genes for different traits can segregate independently.

• Genetic Variation:

  • Caused by mutation, recombination, and independent assortment.

Evolution

• Natural Selection:

  • Mechanism by which individuals with favorable traits reproduce more successfully.

• Speciation:

  • Formation of new species through processes such as allopatric and sympatric speciation.

• Evolutionary Evidence:

  • Fossil records, comparative anatomy, molecular biology, and embryology.

Ecology

• Ecosystem:

  • A community of living organisms interacting with their environment.

• Biomes:

  • Major ecological community defined by climate and vegetation (e.g., forests, deserts).

• Food Chains/Webs:

  • Illustrate the flow of energy through trophic levels: producers → consumers → decomposers.

Human Biology

• Organ Systems:

  • Circulatory, respiratory, digestive, nervous, endocrine, and immune systems.

• Homeostasis:

  • The body’s ability to maintain stable internal conditions despite external changes.

• Cellular Respiration:

  • Process by which cells convert glucose and oxygen into energy (ATP), carbon dioxide, and water.

Plant Biology

• Photosynthesis:

  • Process by which plants convert sunlight into chemical energy (glucose).
  • Occurs in chloroplasts; equation: 6CO2 + 6H2O + light → C6H12O6 + 6O2.

• Plant Structures:

  • Roots (absorption of water/nutrients), stems (support and transport), leaves (photosynthesis).

Microbiology

• Bacteria:

  • Single-celled prokaryotes; can be beneficial (gut flora) or pathogenic.

• Viruses:

  • Acellular entities that require a host cell to replicate; consist of DNA or RNA surrounded by a protein coat.

• Fungi:

  • Eukaryotic organisms that decompose organic material; can be unicellular (yeast) or multicellular (mushrooms).

Biotechnology

• Genetic Engineering:

  • Techniques used to alter the genetic makeup of organisms (e.g., CRISPR, recombinant DNA).

• Biotechnology Applications:

  • Agriculture (GMOs), medicine (gene therapy, vaccines), and environmental (bioremediation).

Cell Structure and Function

• Prokaryotic cells are defined by the absence of a nucleus and membrane-bound organelles, containing circular DNA located in the nucleoid.
• Examples of prokaryotic cells include Bacteria and Archaea.
• Eukaryotic cells contain a nucleus and membrane-bound organelles; their linear DNA is associated with histones.
• Examples of eukaryotic cells include plant cells, animal cells, fungi, and protists.

Genetics

• DNA is structured as a double helix composed of four nucleotides: adenine (A), thymine (T), cytosine (C), and guanine (G).
• Base pairing rules are A pairing with T and C pairing with G.
• Mendelian genetics includes the Law of Segregation, stating that alleles separate during gamete formation.
• The Law of Independent Assortment indicates that genes for different traits can segregate independently.
• Genetic variation arises from mutation, recombination, and independent assortment.

Evolution

• Natural selection is a mechanism by which individuals with advantageous traits have higher reproductive success.
• Speciation is the process of forming new species, occurring through allopatric (geographic separation) and sympatric (same location) methods.
• Evidence for evolution is found in fossil records, comparative anatomy, molecular biology, and embryological development.

Ecology

• An ecosystem consists of a community of living organisms interacting with their environment.
• Biomes are defined ecological communities characterized by specific climate and vegetation types, such as forests and deserts.
• Food chains and food webs illustrate energy flow through ecosystems, transitioning from producers to consumers and decomposers.

Human Biology

• Major organ systems include the circulatory, respiratory, digestive, nervous, endocrine, and immune systems.
• Homeostasis refers to the body's capacity to maintain stable internal conditions despite external fluctuations.
• Cellular respiration is a metabolic process that converts glucose and oxygen into energy (ATP), generating carbon dioxide and water as byproducts.

Plant Biology

• Photosynthesis allows plants to convert sunlight into chemical energy, specifically glucose, through the equation: 6CO2 + 6H2O + light → C6H12O6 + 6O2.
• Key plant structures include roots for water/nutrient absorption, stems for support and transport, and leaves for conducting photosynthesis.

Microbiology

• Bacteria are single-celled prokaryotes that can be beneficial (e.g., gut flora) or pathogenic, causing diseases.
• Viruses are acellular entities that need a host cell to replicate and consist of either DNA or RNA encased in a protein coat.
• Fungi are eukaryotic organisms that play a role in decomposition; they can be unicellular like yeast or multicellular like mushrooms.

Biotechnology

• Genetic engineering encompasses various techniques to modify organisms' genetic material, including CRISPR and recombinant DNA technologies.
• Applications of biotechnology are diverse, spanning agriculture (such as GMOs), medicine (gene therapy and vaccines), and environmental management (bioremediation).

This quiz covers fundamental concepts of cell structure, including prokaryotic and eukaryotic cells, as well as key topics in genetics like DNA structure and Mendelian principles. Additionally, it explores natural selection and speciation. Test your understanding of these crucial biological concepts.