Cell Structure and Function

Cell Structure and Function

• Cells are the basic units of life, exhibiting a wide range of structures and functions.
• Prokaryotic cells (bacteria and archaea) lack a nucleus and membrane-bound organelles.
• Eukaryotic cells (plants, animals, fungi, protists) possess a nucleus and various organelles.
• Key organelles and their functions include:
  • Nucleus: Control center of the cell, containing DNA.
  • Mitochondria: Powerhouse of the cell, generating ATP through cellular respiration.
  • Endoplasmic reticulum (ER): Involved in protein synthesis and lipid metabolism.
  • Golgi apparatus: Modifies, sorts, and packages proteins.
  • Ribosomes: Synthesize proteins.
  • Lysosomes: Contain enzymes to break down cellular waste.
  • Vacuoles: Storage compartments in plant cells.
• Cell membranes are selectively permeable, regulating the passage of materials into and out of the cell.
• Plasma membrane: Composed of a phospholipid bilayer with embedded proteins.
• Fluid mosaic model describes the dynamic nature of the membrane.

Cell Processes

• Cellular respiration is a metabolic process that converts energy stored in glucose into ATP (adenosine triphosphate).
• Photosynthesis is a metabolic process that converts light energy into chemical energy stored in glucose.
• Mitosis is a type of cell division that results in two genetically identical daughter cells.
• Meiosis is a specialized type of cell division that reduces the chromosome number by half, producing gametes (sex cells).
• Active transport moves molecules against their concentration gradient, requiring energy.
• Passive transport moves molecules down their concentration gradient without energy.
• Diffusion, osmosis, and facilitated diffusion are examples of passive transport.
• DNA replication is the process by which DNA is copied.
• Transcription is the process where DNA is converted into RNA.
• Translation is the process where RNA is used to synthesize proteins.

Genetics

• DNA is the genetic material, a double helix structure.
• Genes are segments of DNA that code for proteins.
• Alleles are different forms of a gene.
• Genotype refers to the genetic makeup, while phenotype refers to the observable traits.
• Mendelian genetics describes patterns of inheritance based on dominant and recessive alleles.
• Non-Mendelian genetics includes more complex inheritance patterns, such as codominance and incomplete dominance.
• Gene expression involves transcribing and translating a gene into a protein.
• Mutations are changes in DNA sequence that can lead to variations in traits.

Ecology

• Ecology studies the relationships between organisms and their environment.
• Biomes are large-scale ecosystems defined by climate and vegetation.
• Food webs depict the feeding relationships between organisms in an ecosystem.
• Population dynamics study how populations change over time.
• Community ecology examines interactions between different species.
• Conservation biology focuses on preserving biodiversity and ecosystems.
• Carrying capacity is the maximum population size an environment can support.

Evolution

• Evolution is the change in heritable characteristics of biological populations over successive generations.
• Natural selection is a key mechanism of evolution, favoring traits that increase survival and reproduction.
• Adaptations are traits that enhance an organism's ability to survive and reproduce in a specific environment.
• Speciation is the process by which new species arise.
• Phylogenetic trees depict evolutionary relationships between organisms.
• Taxonomy classifies organisms based on shared characteristics.

Morphology

• Morphology refers to the form and structure of organisms.
• Anatomical features are observed structures within organisms.
• Comparative anatomy studies similarities and differences in structures across different species.
• Morphology informs evolutionary relationships and the evolution of organisms.