Cell Theory, Osmosis, and Cell Types

• Cell theory posits that all living organisms are composed of cells, the cell is the basic unit of life, and all cells arise from pre-existing cells.

Osmosis and Diffusion (Passive Transport)

• Osmosis and diffusion are passive transport mechanisms that do not require energy input.
• Diffusion is the movement of molecules from an area of high concentration to an area of low concentration.
• Osmosis is the movement of water across a semi-permeable membrane from an area of high water concentration (low solute concentration) to an area of low water concentration (high solute concentration).

Prokaryotic and Eukaryotic Cells

• Prokaryotic cells lack a nucleus and other membrane-bound organelles; examples include bacteria and archaea.
• Eukaryotic cells possess a nucleus and other membrane-bound organelles like mitochondria and endoplasmic reticulum; examples include plant and animal cells.
• Internal structures such as ribosomes, DNA, and cytoplasm are present in both cell types, but their organization differs significantly.

Fermentation, Aerobic Respiration, ATP, and Photosynthesis

• Fermentation is an anaerobic process that breaks down glucose incompletely, yielding a small amount of ATP and byproducts like lactic acid or ethanol.
• Aerobic respiration is the process of breaking down glucose in the presence of oxygen to produce a large amount of ATP.
• ATP (adenosine triphosphate) is the primary energy carrier molecule in cells, providing energy for various cellular processes.
• Photosynthesis is the process by which plants and some bacteria convert light energy into chemical energy in the form of glucose, using carbon dioxide and water.

Endocytosis and Exocytosis (Active Transport)

• Endocytosis is an active transport process where cells engulf substances from their surroundings by forming vesicles.
• Phagocytosis is a form of endocytosis involving the engulfment of large particles or cells ("cell eating").
• Pinocytosis is a form of endocytosis involving the engulfment of liquid and small molecules ("cell drinking").
• Exocytosis is an active transport process where cells release substances into their surroundings by fusing vesicles with the plasma membrane.

Surface Area to Volume Ratio

• Microscopic organisms have a high surface area to volume ratio, which enhances nutrient absorption and waste elimination efficiency.
• As cell size increases, the surface area to volume ratio decreases, making it more difficult for cells to efficiently exchange materials with their environment.

Cell Membrane

• The cell membrane is composed of a phospholipid bilayer with embedded proteins.
• Phospholipids form a barrier to water-soluble substances.
• Proteins in the cell membrane perform various functions, including transport, enzymatic activity, signal transduction, cell-cell recognition, intercellular joining, and attachment to the cytoskeleton and extracellular matrix.

Food Preservation

• Different methods used for food preservation include:
  • Heating (pasteurization)
  • Cooling (refrigeration, freezing)
  • Drying
  • Adding preservatives (salt, sugar, acids)
  • Irradiation
  • Modified atmosphere packaging

Plant and Animal Cells and Autotrophs/Heterotrophs

• Plant cells contain chloroplasts for photosynthesis and a cell wall for structural support, which are absent in animal cells.
• Animal cells have centrioles and lack cell walls and chloroplasts.
• Autotrophs, like plants, produce their own food through photosynthesis.
• Heterotrophs, like animals, obtain nutrients by consuming other organisms.

Scientific Method

• The scientific method involves:
  • Forming a hypothesis (a testable explanation).
  • Identifying variables (independent, dependent, and controlled).
  • Keeping constants (factors that are kept the same).
  • Collecting and analyzing data.
  • Interpreting data and graphs to draw conclusions.

Microbes

• Bacteria are single-celled prokaryotic organisms that can be beneficial or harmful.
• Viruses are non-cellular entities that require a host cell to replicate.
• Yeast is a unicellular fungus used in processes like fermentation.

Role of Decomposers

• Decomposers, such as fungi and bacteria, break down dead organic matter, releasing nutrients back into the environment.

Mitosis and Binary Fission

• Mitosis is a process of cell division in eukaryotic cells that results in two identical daughter cells, used for growth and repair.
• Binary fission is a simpler process of cell division in prokaryotic cells, resulting in two identical daughter cells.

SHE Criteria

• SHE Criteria, or Science, Health and Environment, is not present in the text from the User. As such, it is impossible to define an example of a SHE criteria.