Biology Cell Theory and Cellular Processes

Cell Biology

• Osmosis: Movement of water molecules through a semi-permeable membrane from a lower solute concentration region to a higher solute concentration region.
• Ribosome: Cellular structure responsible for protein synthesis by translating messenger RNA into polypeptides.
• Fermentation: Anaerobic process where cells convert sugars into alcohol or acids to generate energy.

Cell Theory

• All living organisms are made up of one or more cells.
• The cell is the basic unit of structure and function in all living organisms.
• All cells come from pre-existing cells through cell division.

Equations

• Fermentation: Glucose → Alcohol + Carbon dioxide (in yeast), Glucose → Lactic acid (in muscles)
• Respiration: Glucose + Oxygen → Carbon dioxide + Water + Energy

Prokaryote and Eukaryote

• Prokaryote: Unicellular, no nucleus, smaller in size, DNA in a nucleoid region, example: Bacteria
• Eukaryote: Multicellular, has a nucleus, larger in size, DNA contained within the nucleus, example: Plants, animals

Surface Area to Volume Ratio

• Cells with a higher surface area to volume ratio can efficiently exchange materials with their environment
• Smaller cells typically have a higher ratio, which is advantageous for nutrient uptake and waste removal

Food Preservation Techniques

• Methods include refrigeration, freezing, drying, salting, canning, and pickling
• These techniques inhibit bacterial growth by altering conditions such as temperature, moisture, and pH

Cell Parts and Functions

• Animal Cell:
  • Nucleus: Contains genetic material
  • Mitochondria: Produces energy
  • Ribosome: Synthesizes proteins
  • Cell membrane: Controls entry and exit of substances
• Plant Cell:
  • Chloroplast: Photosynthesis
  • Cell wall: Provides structure and support
  • Vacuole: Stores nutrients and waste products

Differences Between Plant and Animal Cells

• Plant Cells:
  • Have a cell wall
  • Contain chloroplasts
  • Have a large central vacuole
• Animal Cells:
  • No cell wall
  • No chloroplasts
  • Smaller vacuoles

Food Preservation Techniques

• Refrigeration/Freezing: Slows down microbial growth by lowering temperature
• Drying/Dehydration: Removes water, which is essential for microbial growth
• Salting: Draws out moisture through osmosis, creating an inhospitable environment for microbes
• Canning: Kills microbes by heating and seals the food in airtight containers
• Pickling: Uses acidic conditions to inhibit microbial growth

Practical Question

• Variables:
  • Independent: Variable that is changed
  • Dependent: Variable that is measured
  • Controlled: Variables that are kept constant
• Data Reliability and Accuracy:
  • Reliability: Consistency of results over repeated trials
  • Accuracy: How close results are to the true value
• Graphing:
  • Label axes, plot points, draw a line or curve
• Conclusion:
  • Summarize the results and determine if the hypothesis is supported

Cell Division

• Binary Fission:
  • DNA replication, chromosome segregation, cytokinesis
• Mitosis:
  • Prophase, metaphase, anaphase, telophase, cytokinesis

Fermentation Word Equations

• Glucose → Ethanol + Carbon dioxide (Yeast)
• Glucose → Lactic acid (Muscle cells)

Usefulness of Microbes

• Decomposition: Break down organic matter, recycling nutrients
• Food Production: Used in making bread, yogurt, cheese, beer, and wine
• Medicine: Production of antibiotics, vaccines, and insulin
• Biotechnology: Genetic engineering, bioremediation
• Nitrogen Fixation: Convert atmospheric nitrogen into forms usable by plants