Cell Structure and Organelles

Cell Biology

Cell Structure

• Plasma Membrane: A semi-permeable membrane that surrounds the cell, regulating what enters and leaves.
• Cytoplasm: A jelly-like substance inside the cell where metabolic processes take place.
• Nucleus: The control center of the cell, containing most of the cell's genetic material (DNA).
• Mitochondria: Organelles responsible for generating energy for the cell through cellular respiration.
• Endoplasmic Reticulum (ER): A network of membranous tubules and cisternae involved in protein synthesis, folding, and transport.
• Ribosomes: Small organelles found throughout the cytoplasm, responsible for protein synthesis.
• Lysosomes: Membrane-bound sacs containing digestive enzymes, responsible for breaking down and recycling cellular waste and foreign substances.
• Golgi Apparatus: A complex of flattened sacs and tubules involved in protein modification, sorting, and packaging.

Cell Functions

• Metabolism: The sum of all chemical reactions that occur within a cell, including energy production, synthesis, and degradation.
• Protein Synthesis: The process by which cells create proteins, involving transcription, translation, and post-translational modification.
• Cell Division: The process by which a cell divides into two daughter cells, including mitosis and cytokinesis.
• Cell Signaling: The communication between cells, involving the transmission and reception of signals through signaling pathways.

Cell Transport

• Passive Transport: Movement of molecules from high to low concentration without energy input, including diffusion, osmosis, and facilitated diffusion.
• Active Transport: Movement of molecules against their concentration gradient, requiring energy input, such as carrier proteins and pumps.

Cell Cycle and Division

• Interphase: The longest stage of the cell cycle, during which the cell grows, replicates its DNA, and prepares for cell division.
• Mitosis: The process of nuclear division, resulting in two daughter cells with identical genetic material.
• Cytokinesis: The process of cytoplasmic division, resulting in two separate daughter cells.

Cellular Organelles and Inclusions

• Centrioles: Small, cylindrical organelles involved in the formation of cilia, flagella, and the spindle fibers during cell division.
• Chloroplasts: Organelles found in plant cells, responsible for photosynthesis and producing glucose.
• Vacuoles: Membrane-bound sacs that store water, salts, and other substances, and help maintain cellular turgor pressure.
• Peroxisomes: Small organelles involved in the breakdown of fatty acids and amino acids.

Cell Biology

Cell Structure

• Plasma membrane is semi-permeable, regulating what enters and leaves the cell.
• Cytoplasm is a jelly-like substance where metabolic processes occur.
• Nucleus contains most of the cell's genetic material (DNA) and is the control center.
• Mitochondria generate energy for the cell through cellular respiration.
• Endoplasmic Reticulum (ER) is a network of membranous tubules and cisternae involved in protein synthesis, folding, and transport.
• Ribosomes are small organelles found throughout the cytoplasm, responsible for protein synthesis.
• Lysosomes contain digestive enzymes, breaking down and recycling cellular waste and foreign substances.
• Golgi Apparatus is a complex of flattened sacs and tubules involved in protein modification, sorting, and packaging.

Cell Functions

• Metabolism is the sum of all chemical reactions that occur within a cell, including energy production, synthesis, and degradation.
• Protein synthesis involves transcription, translation, and post-translational modification.
• Cell division involves the process of a cell dividing into two daughter cells, including mitosis and cytokinesis.
• Cell signaling involves the communication between cells, transmitting and receiving signals through signaling pathways.

Cell Transport

• Passive transport occurs without energy input, moving molecules from high to low concentration, including diffusion, osmosis, and facilitated diffusion.
• Active transport requires energy input, moving molecules against their concentration gradient, involving carrier proteins and pumps.

Cell Cycle and Division

• Interphase is the longest stage of the cell cycle, during which the cell grows, replicates its DNA, and prepares for cell division.
• Mitosis is the process of nuclear division, resulting in two daughter cells with identical genetic material.
• Cytokinesis is the process of cytoplasmic division, resulting in two separate daughter cells.

Cellular Organelles and Inclusions

• Centrioles are involved in the formation of cilia, flagella, and the spindle fibers during cell division.
• Chloroplasts are organelles found in plant cells, responsible for photosynthesis and producing glucose.
• Vacuoles store water, salts, and other substances, helping maintain cellular turgor pressure.
• Peroxisomes are involved in the breakdown of fatty acids and amino acids.

Organic Chemistry

• Study of carbon-containing compounds and their properties, reactions, and synthesis

Characteristics of Organic Compounds

• Contain carbon and hydrogen atoms
• May also contain oxygen, nitrogen, sulfur, and other elements
• Typically have low melting and boiling points
• Are often insoluble in water but soluble in organic solvents
• Can exhibit isomerism (same molecular formula, different structure)

Functional Groups

• A specific group of atoms within a molecule that determines its chemical properties
• Examples of functional groups:
  • Alkyl (R-): a hydrocarbon chain
  • Alkenyl (R'-): a hydrocarbon chain with one or more double bonds
  • Alkynyl (R''): a hydrocarbon chain with one or more triple bonds
  • Hydroxyl (OH): a hydroxyl group
  • Carboxyl (COOH): a carboxylic acid group
  • Amino (NH2): an amino group

Types of Organic Compounds

• Alkanes: saturated hydrocarbons with only single bonds
• Alkenes: unsaturated hydrocarbons with one or more double bonds
• Alkynes: unsaturated hydrocarbons with one or more triple bonds
• Aromatic compounds: planar, ring-shaped molecules with delocalized electrons
• Heterocyclic compounds: ring-shaped molecules with atoms other than carbon

Organic Reactions

• Substitution reactions: a functional group replaces another functional group
• Elimination reactions: a functional group is removed, resulting in a new bond
• Addition reactions: a functional group is added to a molecule
• Oxidation-reduction reactions: a reaction involving the transfer of electrons

Synthesis of Organic Compounds

• Synthesis: the creation of a complex molecule from simpler molecules
• Methods of synthesis:
  • Chemical reactions (e.g., substitution, elimination)
  • Biochemical reactions (e.g., fermentation)
  • Enzyme-catalyzed reactions