Exam 1 Study Guide Flashcards
Explain the Central Dogma:
. The central dogma of molecular biology is a theory stating that genetic information flows only in one direction, transcribed from DNA, to RNA. Then, translated from RNA to protein, or RNA directly to protein.
Describe the 4 characteristics of living things
- Living organisms are complex
- Ability to reproduce
- Able to change in response to environment
- Have the capacity to evolve
Define a Cell:
The simplest self-replicating entity that can exist as an independent unit of life.
•Describe the three essential features of all cells:
- Store and Transmit Information
- Plasma Membrane that separates cell membrane from the environment.
- Harness Energy from the environment — Converts energy from sugar into ATP.
Define matter and element
Matter: Anything that takes up Space and Has Mass
Element: An element is a substance that cannot be broken down into simpler components by chemical Reactions
•Know the four most abundant elements in the human body
Oxygen, Carbon, Nitrogen, and Hydrogen
•Know the structure of an atom and the function of its 3 subatomic particles (protons, neutrons, electrons)
Structure: Electrons exist in the Orbitals surrounding the Nucleus, Protons and Neutrons exist in the Nucleus
Functions:
• Electrons: Provide a Negative Charge
• Protons: Provide a Positive Charge, and Mass
• Neutrons: Provide mass
Differentiate between an atom’s atomic number and atomic mass
An Atom’s Atomic Number is based on the # of Protons (This is what gives an atom its “elemental identity”).
An Atom’s Atomic Mass is determined by the # of Protons and Neutrons (Just measuring mass)
- Electrons also contribute mass, but its a negligible amount so we usually don’t include them.
Define an isotope and an ion and differentiate between the two
Isotope: two or more forms of the same element that contain equal numbers of protons but different numbers of neutrons in their nuclei, and hence differ in relative atomic mass but not in chemical properties
Example: Carbon-12 and Carbon-14.
Ion: an atom or molecule with a net electric charge (+/-) due to the loss or gain of one or more electrons:
Example: Na^(+) or Cl^(-).
•Explain electron orbitals
Electron Orbitals: regions of space where an electron spends most of is time, only 2 electrons can exist in any orbital at one time. Atoms with more than two electrons have multiple orbitals that differ in size, shape, and distance from the nucleus.
•Describe the 4 types of chemical bonds used to make molecules
- Covalent Bonds: Atoms equally share their valance electrons.
- Polar Covalent Bonds: Atoms in-equally share their valance electrons.
- Hydrogen Bonding: Hydrogen bonding is a special type of dipole-dipole attraction between extremely electronegative molecules. Occurs between (H-O), (H-F), (H-N). The attraction is possible because of the Partial Positive/Negative charges.
- Ionic Bonds: Bonding formed between two oppositely charged ions in a chemical compound; like
(Na^+) — (Cl^-)
Describe the properties of water that make it indispensable to life on earth:
• Water is Polar
• Water has a Neutral pH (pH=7)
• Water is an amazing solvent (Dissolving agent).
•Describe the interaction between the atoms of a single molecule of water, and among water molecules
• A single Water Molecule has Polar Covalent Bonds between the (O-H) bonds.
• However, from one water molecule to another, they interact through Hydrogen bonds. This allows the Partial Positive charge on one Hydrogen to be attracted to the Parital Negative charge on another water molecule’s Oxygen!
•Correlate water’s high specific heat with its ability to stabilize temperature fluctuations
Water’s ability to stabilize temperature stems from its high ‘specific heat’
-water changes its temperature less when it absorbs or releases a given amount of heat. Water’s high specific heat is a result of its hydrogen bonding.
Define solution, solute, solvent, aqueous solution
• A solution is a liquid that is a homogeneous mixture of substances
• A solvent is the dissolving agent of a solution
• The solute is the substance that is dissolved
Aqueous Solution: A solution in which water is the solvent is called an aqueous solution.
•Differentiate between hydrophilic and hydrophobic substances
• Hydrophilic Substances are those that are Water-Loving (Polar)
• Hydrophobic Substances are those that are Water-hating (Non-Polar).
Correlate changes in hydrogen ion concentration (H+) with pH
• As the Concentration of Hydrogen Ions increases [H+], pH will go down. (More Acidic Substance)
• Likewise, As the Concentration of Hydrogen Ions DECREASE, the pH will Increase (More Basic Substance).
•Describe the bonding properties of Carbon that relate to its structural diversity
• Carbon atoms form non-polar covalent bonds. It also prefers to bond to 4 others atoms (Forming a tetrahedral Molecular Geometry). Carbon atoms link with one another to form long Carbon “chains;” which can be branched or a ring structure (Cyclical).
•Define an isomer
Isomers: Molecules with the same chemical formula, but arranged differently
• Different Structures
• Different Functions
Describe the basic structure of an amino acid
• Amino Acids have an Amino Group, An Alpha Carbon, a Carboxyl group, and an “R” Group
◦ The “R” Group will change depending on the Amino Acid
•Describe how amino acids link together via peptide bonds to form proteins
• Amnio Acids connect by linking the Carboxyl Group (C=O, C-OH) of Amino Acid #1, to the Nitrogen of the Amino group (NH2) of the Adjacent amino acid (Amino Acid #2); forming a Peptide Bond
◦ This formation produces a Water Molecule
•Identify and Define the three components of a single nucleotide
- The 5-Carbon Containing Sugar (Ribose or Deoxyribose)
- Base Containing Nitrogen
- One or More Phosphate Groups
•Describe the difference between a deoxyribonucleotide and a ribonucleotide
• The main difference between a Deoxyribonucleotide and a Ribonucleotide is the existence of another Hydroxyl group on the 2’ Carbon. This particular (O-H) bond is present in Ribose, but not Deoxyribonucleotide.