Chem. of Life
The identifier of an element and the total number is represented by the atomic number.
What is a proton?
Intermolecular forces between water molecules that is caused by the polar nature of water. This is responsible for surface tension.
What is cohesion?
An organelle in an animal cell that functions as the cell's digestive component with hydrolytic enzymes. It breaks down proteins, polysaccharides, lipids, nucleic acids, and even worn-out organelles.
What is the lysosome?
What is the function of a carbohydrate?
- To serve as an energy source/ storage (glycogen in animals, starch in plants).
- To serve as structural support in cells (cellulose for plant cell walls), as well as to form arthropods' cellular exoskeleton (chitin).
- Key roles in the plasma membrane, which include cell signaling, cell identification, and structure in the membrane.
What are the differences between DNA and RNA?
DNA:
1. Thymine
2. Deoxyribose sugar (2' carbon lacks an oxygen)
3. Typically, double-stranded
4. Store/ carry the cells' genetic blueprint and passes it on from parents to offspring (in the form of chromosomes).
RNA:
1. Uracil
2. Ribose sugar (2' carbon has the full hydroxide)
3. Typically, single-stranded
4. Involved in the production of proteins, which express the hereditary information of an organism.
This is a very weak intermolecular force between molecules due to temporary charges attracting atoms that are very close together.
What is a Van der Waals interaction?
The rigid cell-covering comprised of various molecules that protects the cell, provide structural support, and give shape to the cell.
What is the cell wall?
The protein fiber network that collectively maintains the cell's shape, secures some organelles in specific positions, allows cytoplasm and vesicles to move within the cell, and enables unicellular organisms to move independently.
What is the cytoskeleton?
What is the defining characteristic of a lipid?
A lipid is a macromolecule that is nonpolar and insoluble in water.
What are the four levels of protein structure, and in which can we officially classify the molecule as a "protein?"
1. Primary: The linear sequence of amino acids in a protein, or the polypeptide chain.
2. Secondary: Hydrogen bonding (local folding) within the backbone of a polypeptide chain -- alpha helices and beta-pleated sheets.
3. Tertiary (OFFICIALLY A PROTEIN!!): A protein's three-dimensional conformation that is formed by the interactions between amino acid side chains (the R-groups).
4. Quaternary: Association of discrete polypeptide subunits in a protein. In other words, multiple polypeptide chains/ proteins coming together.
A dehydration synthesis is a reaction that links monomer molecules to form polymers. In each reaction, a water molecule is formed for each bond. In other words, to form a polymer from two monomers, water is RELEASED (a hydrogen and a hydroxide are released to bond the two monomers together).
A hydrolysis reaction is a reaction that breaks a polymer apart into its monomers or smaller polymers. In each reaction, a water molecule is added to separate the molecule and break the bond.
What organelles have a double-membrane?
1. Chloroplasts
2. Mitochondria
3. Nuclear envelope
Eukaryotic organelle comprised of a series of stacked membranes that sorts, tags, and packages lipids and proteins for distribution.
What are the monomers of each macromolecule?
Protein: An amino acid
Carbohydrate: A monosaccharide
Lipid: No true monomer, but most lipids are composed of fatty acids and glycerol (i.e. phospholipids, fats, et cetera).
Nucleic acid: Nucleotides
What is the difference between a polar covalent bond, nonpolar covalent bond, and an ionic bond?
Polar covalent bond: The UNEQUAL sharing of electrons between two atoms, which causes partial charges and permanent dipoles within the molecule (i.e. water!)
Nonpolar covalent bond: The EQUAL sharing of electrons between two atoms, and there are no partial charges located anywhere within the molecule (i.e. carbon dioxide!)
Ionic bond: The ELECTROSTATIC ATTRACTION that occurs between two ions that have transferred/ accepted electrons (a sodium cation and a chloride anion -- Table salt!)
A relatively weak bond between slightly positively charged hydrogen atoms and slightly negatively charged atoms in other molecules.
What is a hydrogen bond?
Friendly reminder that a hydrogen bond on its OWN is weak, but when it is occurring with many, many, many other hydrogen bonds (a large collection of hydrogen bonds throughout a substance), then it is strong! :)
1. One or more cells comprise all organisms/ living things.
2. All cells derive from pre-existing cells.
3. The cell is the basic unit of life.
State some of the similarities and differences between prokaryotic and eukaryotic cells.
1. Similarities: ALL CELLS have ribosomes, a plasma membrane, DNA, and cytoplasm.
2. Differences:
- Size: prokaryotes are 0.1 um to 5.0 um in diameter, while eukaryotes are 10 um to 100 um in diameter.
- Prokaryotes do NOT have membrane-bound organelles; eukaryotes do! In other words, eukaryotes display compartmentalization, which allows each cell to maintain necessary concentrations, distances, and create separation.
- Prokaryotes have a nucleoid, or a concentrated area of circular DNA that exists within the cytoplasm. Eukaryotes, on the other hand, have a nucleus that protects and stores the linear DNA.
What are the bonds formed by dehydration reactions for each macromolecule?
Carbohydrates: Glycosidic linkages
Proteins: Peptide bonds
Nucleic acids: phosphodiester bonds in the sugar-phosphate backbone, hydrogen-bonding between nitrogenous bases.
Lipids: most commonly ester bonds.
What is the difference between an isomer and an isotope?
Isomer: Molecules that differ structurally from one another, even though they share the same chemical formula (For example, many different kinds of sugars exist with the chemical formula C6 H12 O6).
Isotope: One or more forms of an element that have different numbers of neutrons (For example, Carbon-12 versus Carbon 14).
The unique properties of carbon make it a central part of biological molecules, and carbon is the backbone of organic molecules.
What are the unique properties of carbon?
1. Carbon can form four covalent bonds (it has four valence electrons), and it can form single, double, or triple bonds.
2. Carbon-carbon bonds are extremely stable (takes a significant amount of energy to break) and diverse (i.e. isomers).
3. Carbon and hydrogen can form hydrocarbon chains or rings, and these carbon chains provide a skeleton for the molecules essential for life -- the macromolecules!
Water has many properties that are critical to maintaining life.
1. What causes these unique properties?
2. What are three examples of water's unique properties?
1. The polarity of a water molecule from the electronegativity difference between the hydrogens and oxygen atoms, which allows it to form hydrogen bonds (Each water molecule can form four hydrogen bonds).
2. Here are several examples of water's unique properties:
- Water is an excellent solvent: the hydrogen bonds allow ions and other polar molecules to dissolve in water.
- High heat capacity: It takes a considerable amount of added heat to raise the temperature of water. Even as the temperature rises, the hydrogen bonds between water are constantly breaking and forming anew, which allows the overall temperature to remain steady, even as heat is being added.
- High heat of vaporization: It takes a considerable amount of heat to vaporize water, and when water is vaporized, it cools the surface that it was on (i.e. Humans with sweating to cool us off!).
- Cohesive and adhesive forces: Cohesive forces allow for high surface tension, and adhesive forces allow for capillary rise/ action.
- Density of water: Ice (solid water) is less dense than liquid water, which allows for life within bodies of water to survive in the winter time.
What are some of the differences between animal cells and plant cells?
Plant cells have chloroplasts, a large central vacuole, and a cell wall, as well as form plasmodesmata.
Animal cells have lysosomes, centrioles (which engage in cellular division and are part of the mitotic spindle), and several small vacuoles, as well as can form tight junctions and gap junctions.
What is the function of a nucleic acid?
Nucleic acids are the biological macromolecules that carry the cell's genetic blueprint and carry instructions for the cell's functioning.
What are the organelles involved in the endomembrane system, and what is its role?
1. The nuclear envelope, endoplasmic reticulum, lysosomes, Golgi apparatus, vesicles, and the plasma membrane.
2. The endomembrane system is a group of organelles and membranes in eukaryotic cells that work together modifying, packaging, and transporting lipids and proteins.
Here is what each organelle does:
RER: Modifies proteins and synthesizes phospholipids in cell membranes.
SER: Synthesizes carbohydrates, lipids, and steroid hormones, as well as engages in the detoxification of medications and poisons, and stores calcium ions.
Golgi apparatus: Sorting, tagging, packaging, and distributing lipids and proteins.
Lysosomes: Formed by budding RER and Golgi membranes, and these digest macromolecules, recycle worn-out organelles, and destroy pathogens.