Biology Chapter 1 Flashcards

Cell Function and Structure

• Transcription occurs in the nucleus, while translation happens in the cytoplasm.
• The central dogma of molecular biology is expressed as DNA -> RNA -> Protein.
• Liver and kidney cells have the same DNA but express different genes and proteins, leading to distinct roles in the body.
• Prokaryotic cells can evolve rapidly due to large populations and genetic material exchange.

Microscope Usage

• Electron microscopes visualize structures as small as individual molecules by using electron beams.
• Fluorescence microscopes can observe ribosomes due to advanced illumination techniques, achieving resolutions around 20 nm.
• A significant limitation of light microscopy is its inability to resolve structures smaller than 0.5 µm.

Prokaryotic vs Eukaryotic Cells

• Eukaryotic cells possess a nucleus and membrane-bound organelles, unlike prokaryotes.
• All cells share key features, such as nucleic acids and ribosomes.
• Prokaryotes have cell walls surrounding their plasma membranes and can be spherical, rod-like, or spiral in shape.

Evolution and Origin of Cells

• Archaea thrive in extreme environments and share ancestral lineage with both bacteria and eukaryotes.
• The mitochondrion likely originated from engulfed aerobic bacteria, playing a critical role in energy production.

Cellular Processes

• Endocytosis is the process by which eukaryotic cells engulf external materials.
• The Golgi apparatus modifies and packages molecules from the endoplasmic reticulum (ER) for secretion or transport.
• Lysosomes are responsible for intracellular digestion, while peroxisomes facilitate reactions that neutralize toxins.

Organelles and Their Functions

• The nucleus, surrounded by a nuclear envelope, contains DNA and is critical for cell regulation.
• Chloroplasts carry out photosynthesis and have evolved from engulfed photosynthetic bacteria.
• The endoplasmic reticulum serves as the site for synthesizing cell-membrane components and exported materials.

Cytoskeleton and Cellular Dynamics

• The cytoskeleton facilitates cell movements and is composed of actin filaments, microtubules, and intermediate filaments.
• Evidence suggests eukaryotic cells may have evolved as predators, requiring adaptability and complex features like a nuclear compartment.

Model Organisms in Research

• E. coli serves as a model for molecular biology, aiding in understanding DNA replication and protein synthesis.
• Brewer's yeast (Saccharomyces cerevisiae) is significant for studying eukaryotic cell tasks, particularly the cell cycle.
• Arabidopsis thaliana is a model plant used for its rapid growth and relevance to agricultural research.

Fundamental Biological Principles

• Life operates as an autocatalytic process, where DNA and RNA sequence information drives protein synthesis, which in turn facilitates the replication of nucleic acids.

• The cell theory posits that all living cells arise from the division of existing cells, forming the foundation of biological understanding.### Model Organisms in Research

• Arabidopsis thaliana: Serves as a model for studying plant genes; insights gained benefit our understanding of crop development, physiology, and the evolution of plant species.

Drosophila melanogaster (Fruit Fly)

• Foundation of classical genetics research; crucial for understanding genetic influence on multicellular organism development.
• Its genetic similarities to humans provide a platform for studying human development and the genetic underpinnings of diseases.

Caenorhabditis elegans (Nematode Worm)

• Serves as a model for investigating developmental processes relevant to humans.
• Research into its precise 959-cell development offers insights into apoptosis, enhancing understanding of programmed cell death.

Zebrafish

• Transparent in early life stages, facilitating real-time observation of cellular behaviors during development.
• Ideal for studying embryonic development in vivo due to clear visibility of internal processes.

Mouse

• Key model organism for mammalian genetics, development, immunology, and cell biology.
• Nearly all human genes have counterparts in mice, making them invaluable for researching human health and disease mechanisms.
• Mice can be genetically modified to analyze specific gene functions through breeding and mutation.

Human Cells

• Many human cell types can be cultured outside the body, allowing for the study of their behavior and properties in a controlled environment.
• Culturing enables exploration of cellular functions that may not be achievable in living organisms.

Electron Microscopy

• Transmission Electron Microscopy (TEM): Generates 2D images, ideal for viewing detailed internal structures in specimens.
• Scanning Electron Microscopy (SEM): Produces 3D images, providing surface details and topography of objects, enhancing visualization of complex structures.