Key Concepts in Biology

Key Concepts in Biology

Cell Biology

• Cell Theory:
  • All living organisms are composed of cells.
  • The cell is the basic unit of life.
  • All cells arise from pre-existing cells.
• Types of Cells:
  • Prokaryotic: No nucleus, smaller, simpler (e.g., bacteria).
  • Eukaryotic: Nucleus present, larger, complex (e.g., plants, animals).

Genetics

• DNA Structure: Double helix, composed of nucleotides (A, T, C, G).
• Gene: A segment of DNA that encodes a protein.
• Mendelian Genetics:
  • Dominant and Recessive Alleles: Dominant masks recessive in phenotype.
  • Punnett Squares: Tool for predicting genotype and phenotype ratios.

Evolution

• Natural Selection: Process where organisms better adapted to their environment tend to survive and reproduce.
• Evolutionary Evidence:
  • Fossil records
  • Comparative anatomy (homologous structures)
  • Molecular biology (DNA comparisons)

Ecology

• Ecosystem: A community of living organisms and their environment.
• Biomes: Major ecological areas characterized by climate and vegetation (e.g., tundra, rainforest).
• Food Chains/Webs:
  • Producers: Organisms that produce their own food (e.g., plants).
  • Consumers: Organisms that eat other organisms (herbivores, carnivores, omnivores).
  • Decomposers: Break down dead organic matter (e.g., fungi, bacteria).

Physiology

• Homeostasis: The ability of an organism to maintain a stable internal environment.
• Organ Systems:
  • Nervous System: Responsible for transmitting signals and processing information.
  • Circulatory System: Transports nutrients and oxygen, removes waste.
  • Respiratory System: Facilitates gas exchange (oxygen and carbon dioxide).

Botany

• Photosynthesis: Process by which plants convert light energy into chemical energy (glucose).
• Plant Structures:
  • Roots: Anchor plants and absorb water/nutrients.
  • Stems: Support and transport substances.
  • Leaves: Main site of photosynthesis.

Zoology

• Animal Classification:
  • Invertebrates: Animals without a backbone (e.g., insects, mollusks).
  • Vertebrates: Animals with a backbone (e.g., mammals, birds, reptiles).
• Behavior: Study of how animals interact with their environment and each other.

Microbiology

• Microorganisms: Tiny living organisms, usually single-celled (e.g., bacteria, viruses, fungi).
• Roles:
  • Beneficial: Aid in digestion, nutrient cycling, and biotechnology.
  • Pathogenic: Cause diseases in humans, animals, and plants.

Biotechnology

• Genetic Engineering: Manipulation of an organism's DNA to achieve desired traits.
• CRISPR: A technology that allows for precise editing of genes.

Evolution of Life

• Origin of Life Theories: Various hypotheses including abiogenesis and extraterrestrial origins.
• Timeline: Life on Earth has evolved over billions of years, marked by mass extinctions and the emergence of new species.

Study Tips

• Understand concepts rather than memorizing facts.
• Use diagrams and charts for visual learning.
• Practice with past exam questions and quizzes.
• Discuss topics with peers for deeper understanding.

Cell Biology

• Cell Theory states all living organisms are made of cells, which are the basic life unit, and all cells arise from pre-existing cells.
• Prokaryotic Cells: Lacks a nucleus, generally smaller and simpler; examples include bacteria.
• Eukaryotic Cells: Contains a nucleus, larger and more complex; examples include plant and animal cells.

Genetics

• DNA is structured as a double helix, made from nucleotides: adenine (A), thymine (T), cytosine (C), and guanine (G).
• A Gene is a DNA segment encoding a protein.
• Mendelian Genetics: Dominant alleles mask recessive alleles in phenotypic expression.
• Punnett Squares help predict the genotype and phenotype ratios of offspring.

Evolution

• Natural Selection is the process where organisms better suited to their environment survive and reproduce more effectively.
• Evidence for evolution includes fossil records, comparative anatomy (homologous structures), and molecular biology (DNA comparisons).

Ecology

• An Ecosystem consists of a community of living organisms along with their physical environment.
• Biomes are large ecological areas defined by climate and vegetation types, such as tundra and rainforest.
• Food Chains/Webs illustrate energy flow:
  • Producers (e.g., plants) create their own food.
  • Consumers (herbivores, carnivores, omnivores) rely on other organisms for food.
  • Decomposers (e.g., fungi, bacteria) recycle nutrients by breaking down dead organic matter.

Physiology

• Homeostasis is the ability to maintain a stable internal environment within an organism.
• Organ Systems include:
  • Nervous System: Processes information and transmits signals.
  • Circulatory System: Carries nutrients and oxygen throughout the body while removing wastes.
  • Respiratory System: Manages gas exchange, specifically oxygen intake and carbon dioxide expulsion.

Botany

• Photosynthesis converts light energy into chemical energy in the form of glucose.
• Key plant structures include:
  • Roots: Anchor plants and absorb water/nutrients from the soil.
  • Stems: Provide support and transport substances within the plant.
  • Leaves: The main site for photosynthesis activities.

Zoology

• Animal classification divides into:
  • Invertebrates: Animals lacking a backbone (e.g., insects, mollusks).
  • Vertebrates: Animals with a backbone (e.g., mammals, birds, reptiles).
• Animal Behavior examines interactions among animals and between animals and their environments.

Microbiology

• Microorganisms are tiny, often single-celled organisms, including bacteria, viruses, and fungi.
• They can be Beneficial (supporting digestion, nutrient cycling, and biotechnology) or Pathogenic (causing diseases in various organisms).

Biotechnology

• Genetic Engineering involves manipulating an organism’s DNA to attain specific traits or outcomes.
• CRISPR technology allows precise editing of genes, facilitating advancements in genetics.

Evolution of Life

• The Origin of Life Theories propose explanations such as abiogenesis or extraterrestrial origins.
• A Timeline of Life indicates Earth's biological evolution over billions of years, highlighted by mass extinctions and species emergences.

Study Tips

• Focus on understanding concepts instead of rote memorization.
• Utilize diagrams and charts for effective visual learning.
• Engage with past exam questions and quizzes for practical knowledge application.
• Collaborate with peers to enhance understanding of complex topics.