Biology: Cell Structure and Function

Cell Structure and Function

• Cell Theory:

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

• Prokaryotic Cells:

  • Lack a nucleus; DNA is in the nucleoid.
  • Typically smaller and simpler.
  • Examples: Bacteria and Archaea.

• Eukaryotic Cells:

  • Have a nucleus and membrane-bound organelles.
  • Larger and more complex.
  • Examples: Plant, animal, fungal, and protist cells.

Genetics

• DNA Structure:

  • Double helix made of nucleotides (A, T, C, G).
  • Base pairing: A with T, C with G.

• Genes:

  • Units of heredity; segments of DNA that code for proteins.

• Genotype vs. Phenotype:

  • Genotype: genetic makeup.
  • Phenotype: observable traits.

• Mendelian Genetics:

  • Principles of inheritance discovered by Gregor Mendel.
  • Dominant and recessive traits; law of segregation and independent assortment.

Evolution

• Natural Selection:

  • Mechanism of evolution proposed by Charles Darwin.
  • Individuals better adapted to their environment tend to survive and reproduce.

• Speciation:

  • Formation of new and distinct species in the course of evolution.

• Evidence of Evolution:

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

Ecology

• Ecosystems:

  • Biological communities interacting with their environments.
  • Components: producers, consumers, decomposers.

• Biomes:

  • Large geographical areas with distinct climates and ecosystems.
  • Examples: deserts, forests, grasslands.

• Food Chains and Webs:

  • Food chain: linear sequence of energy transfer.
  • Food web: complex network of feeding relationships.

Human Anatomy and Physiology

• Major Systems:

  • Circulatory: transports nutrients and oxygen.
  • Respiratory: exchanges gases (O2 and CO2).
  • Digestive: breaks down food for energy.
  • Nervous: controls and coordinates body activities.

• Homeostasis:

  • Regulation of internal conditions (temperature, pH, etc.) to maintain a stable environment.

Plant Biology

• Photosynthesis:

  • Process by which plants convert light energy into chemical energy (glucose).
  • Occurs in chloroplasts; involves chlorophyll.

• Plant Structures:

  • Roots: absorb water and nutrients.
  • Stems: support and transport.
  • Leaves: site of photosynthesis.

Microbiology

• Bacteria:

  • Single-celled prokaryotes; can be beneficial or pathogenic.

• Viruses:

  • Non-living entities that require a host to replicate.

• Fungi:

  • Eukaryotic decomposers; play a critical role in nutrient cycling.

Biochemistry

• Macromolecules:

  • Proteins, nucleic acids, carbohydrates, and lipids.

• Enzymes:

  • Biological catalysts that speed up chemical reactions.

• Metabolism:

  • Sum of all chemical reactions in an organism, involving energy transformation.

Biotechnology

• Genetic Engineering:

  • Manipulation of an organism's DNA to alter characteristics.

• CRISPR:

  • A gene-editing technology that allows for precise modifications to DNA.

• Cloning:

  • Creation of a genetically identical copy of an organism.

Cell Structure and Function

• Cell theory establishes that all living organisms are made of cells, which serve as the basic unit of life, and that all cells originate from existing cells.
• Prokaryotic cells are smaller and simpler, lacking a nucleus, with DNA located in the nucleoid region. They include examples such as bacteria and archaea.
• Eukaryotic cells are larger and more complex, characterized by a nucleus and membrane-bound organelles. They are found in plants, animals, fungi, and protists.

Genetics

• DNA is structured as a double helix composed of nucleotides: adenine (A), thymine (T), cytosine (C), and guanine (G), with base pairing rules where A pairs with T and C pairs with G.
• Genes are segments of DNA that act as units of heredity, coding for specific proteins within organisms.
• Genotype refers to the genetic composition of an individual, while phenotype represents the observable traits influenced by genotype.
• Mendelian genetics, foundational to the study of inheritance, was pioneered by Gregor Mendel and includes concepts such as dominant and recessive traits, as well as the laws of segregation and independent assortment.

Evolution

• Natural selection, articulated by Charles Darwin, is the evolutionary mechanism where individuals better suited to their environment are more likely to survive and reproduce.
• Speciation is the process through which new and distinct species arise over time.
• Evidence supporting the theory of evolution includes fossil records, studies of comparative anatomy, molecular biology findings, and biogeographical distributions.

Ecology

• Ecosystems consist of biotic communities that interact with their abiotic environment, featuring components such as producers, consumers, and decomposers.
• Biomes are large geographical areas defined by specific climatic conditions and distinct ecosystems; examples include deserts, forests, and grasslands.
• Food chains illustrate a linear pathway of energy transfer within an ecosystem, whereas food webs depict complex feeding relationships among various organisms.

Human Anatomy and Physiology

• Major systems in the human body include:
  • Circulatory system: responsible for nutrient and oxygen transport.
  • Respiratory system: facilitates gas exchange (oxygen and carbon dioxide).
  • Digestive system: processes food to extract energy.
  • Nervous system: manages and coordinates bodily functions.
• Homeostasis refers to the physiological process of maintaining internal stability, such as regulating temperature and pH.

Plant Biology

• Photosynthesis is the process where plants convert sunlight into chemical energy (glucose), occurring in chloroplasts and utilizing chlorophyll.
• Essential plant structures include:
  • Roots: involved in water and nutrient absorption.
  • Stems: provide support and facilitate transport.
  • Leaves: the primary site for photosynthesis.

Microbiology

• Bacteria are single-celled prokaryotes that can have beneficial or harmful effects on their environment.
• Viruses are classified as non-living entities that must infect a host to replicate and proliferate.
• Fungi are eukaryotic organisms that function as decomposers, playing a vital role in the cycling of nutrients within ecosystems.

Biochemistry

• Macromolecules essential for life include proteins, nucleic acids (DNA and RNA), carbohydrates, and lipids.
• Enzymes serve as biological catalysts, increasing the rate of chemical reactions vital for cellular functions.
• Metabolism encompasses all biochemical reactions within an organism, involving energy transformations to sustain life.

Biotechnology

• Genetic engineering refers to the intentional manipulation of an organism's DNA to change its traits or functions.
• CRISPR is a groundbreaking gene-editing technology that enables precise alterations in DNA sequences.
• Cloning involves producing a genetically identical copy of a living organism, often using somatic cell nuclear transfer techniques.

Explore the fundamental principles of cell structure and function in this quiz. Learn about prokaryotic and eukaryotic cells, as well as key concepts in genetics such as DNA structure and inheritance. This quiz also touches on evolution and natural selection principles.