Cell Biology: Exploring the Fundamentals of Life
Chapter 2: Chemical Foundations of Life
Key Concepts
- Hydrogen bond: Weak attraction between a hydrogen atom and another atom.
- Cohesion: Attraction between molecules of the same substance.
- Adhesion: Attraction between molecules of different substances.
- Mixture: Material composed of two or more elements or compounds, physically mixed but not chemically combined.
- Solution: Mixture where components are evenly distributed.
- Solute: Substance that is dissolved in a solution.
- Solvent: Dissolving substance in a solution.
- pH scale: Measures the concentration of H+ ions in a solution, ranging from 0 to 14. 0-7 is acidic, 7 is neutral (like water), and 7-14 is basic.
- Glycogen: A complex carbohydrate where animals store energy.
- Monomer: Small chemical unit that makes up a polymer.
- Polymer: Molecule composed of many monomers; makes up macromolecules.
- Reactant: Element or compound that enters into a chemical reaction.
- Product: Element or compound produced by a chemical reaction.
- Activation energy: Energy needed to get a reaction started.
- Enzyme: Protein catalyst that speeds up the rate of specific biological reactions.
Carbon and Macromolecules
- Carbon atoms have four valence electrons, allowing them to form strong covalent bonds with other elements.
- Carbohydrates: Compounds made up of carbon, hydrogen, and oxygen in a ratio of 1:2:1.
- Lipids: Include fats, oils, and waxes.
Chapter 7: Cell Structure and Function
Key Concepts
- Cell membrane: Regulates what enters and leaves the cell.
- Nucleus: Center of an atom, contains protons and neutrons. In biology, it’s the control center of a eukaryotic cell, containing DNA.
- Eukaryote: Organism whose cells contain a nucleus.
- Prokaryote: Unicellular organism that lacks a nucleus.
- Diffusion: Particles move from an area where they are more concentrated to an area where they are less concentrated.
- Facilitated diffusion: Process of diffusion in which molecules pass across the membrane through cell membrane channels.
- Osmosis: Diffusion of water through a selectively permeable membrane.
- Isotonic: When the concentration of two solutions is the same.
- Hypertonic: Solution with the greater concentration of solutes.
- Hypotonic: Solution with the lower concentration of solutes.
Chemical Bonds and Atomic Structure
- Ionic bond: Formed by the transfer of electrons between atoms, resulting in oppositely charged ions that attract each other (e.g., sodium and chloride).
- Atomic mass: Number of protons and neutrons in an atom.
- Atomic number: Number of protons in the nucleus of an atom.
- Covalent bond: Formed by the sharing of electron pairs between atoms.
- Ion: An atom with an electric charge due to the gain or loss of electrons.
Water and Solutions
- Polarity of water: Water is polar due to its bent shape and the uneven distribution of electron charge, making it a good solvent.
- Hydrophobic: Substances that fail to mix with water.
- Unsaturated solution: The solute concentration is lower than the equilibrium solubility.
- Isotope: Two or more forms of the same element that have equal protons but different neutrons.
Cellular Processes and Macromolecules
- Cellular respiration: Begins in the cytoplasm with glycolysis, then proceeds to the Krebs cycle, and lastly, oxidative phosphorylation in the mitochondria.
- Four macromolecules: Lipids, carbohydrates, proteins, and nucleic acids.
- Endocytosis: Process by which cells take in matter by engulfing it with their membranes, forming a vacuole.
- Exocytosis: Process by which the contents of a cell vacuole are released to the exterior.
- Autotroph: Organism able to form nutritional organic substances from simple inorganic substances (e.g., plants).
- Heterotroph: Organism deriving its nutritional requirements from complex organic substances (e.g., animals).
- Fermentation: Process where a substance breaks down into simpler substances without oxygen.
- Homeostasis: Ability of an organism or environment to maintain a state of internal balance.
- Phospholipid: Major component of cell membranes, with a hydrophilic head and hydrophobic tails, forming a bilayer that surrounds and protects internal cell components.
- Hormone: Chemical released in one part of the body that travels through the blood to another area where it regulates specific processes.
Pioneers of Cell Biology
Robert Hooke
- First observed cells in a cork slice using a primitive compound microscope.
- He only saw cell walls as this was dead tissue.
- Coined the term “cell” for these individual compartments he saw.
Antonie van Leeuwenhoek
- Best known for his pioneering work in microscopy and contributions to microbiology.
- Discovered “protozoa” – single-celled organisms he called “animalcules”.
Matthias Schleiden
- German botanist who introduced the idea that plants consist of cells.
- Recognized the importance of the cell nucleus and its connection with cell division.
Theodor Schwann
- Demonstrated that animal tissues are composed of cells.
- Concluded that all tissues are made up of cells, laying the foundation for the cell theory.
- Defined the cell as the basic unit of animal structure.
The Cell Theory
The three parts of the cell theory are:
- All living things are made up of cells.
- Cells are the smallest units (or most basic building blocks) of life.
- All cells come from preexisting cells through the process of cell division.
Key Organelles
Golgi Apparatus
packages proteins into membrane-bound vesicles inside the cell before the vesicles are sent to their destination. In both plant and animal cells
Rough endoplasmic reticulum is an organelle found in eukaryotic cells. Its main function is to produce proteins. It is made up of cisternae, tubules and vesicles. The cisternae are made up of flattened membrane disks, which are involved in the modification of proteins both plant and animal cells
Smooth endoplasmic reticulum: The main function of the smooth ER is to make cellular products like hormones and lipids found in both plant and animal cells