Atomic Structure and Periodic Trends
Which two subatomic particles together determine an atom’s mass?
Protons and Neutrons
What type of bond results from unequal sharing of electrons between atoms?
Polar Covalent Bonds
What happens to pH when [H⁺] increases in a solution?
It becomes more acidic
Give a one-sentence example of the organelle level (use mitochondrion or nucleus).
The organelle level is described as a component of the cell that works to keep the cell functioning. Ex: Nucleus, Mitochondria, Smooth ER, etc.
When atoms join by sharing electrons to make the basis of biological structures, what are those products called?
Molecules
What is a mole? Give its numeric value.
A unit of measurement that determines the number of atoms present in a solution. 6.022x10^23
Name the interaction responsible for water’s cohesion and high surface tension.
Hydrogen Bonds
Define a buffer and state its role in biological systems in one sentence.
It will control the pH from becoming to acidic or basic in the blood stream. this allows enzymes to function properly for chemical reactions to take place.
Using the heart, explain the difference between tissue level and organ level in one or two sentences.
Tissues are made up of two or more cells/cell types. Organs are made up of 2 or more tissue types.
Name one essential element and one trace element important to organisms, and give one biological role for each.
Carbon, building block of all organic matter
Iodine, allows for function and growth of the thyroid
Explain briefly why elements in the same column (group) of the periodic table have similar chemical behavior.
These atoms have the same number of valence electrons
Which bond type generally does NOT dissolve in water? Explain in one sentence why.
Nonpolar Covalent; there are not charges associated in nonpolar covalent because the electronegativities of both atoms are around or near the same.
Human blood is ~pH 7.4. Explain how the carbonic acid–bicarbonate buffer helps prevent large pH drops when lactic acid is produced during intense exercise.
The bicarbonate buffer works to stop pH drops by binding to the H+ ions in the blood and going from a strong bicarbonate base into a weak one.
Describe how hydrogen bonds contribute to DNA structure.
Hydrogen bonds help keep the nucleotides of DNA together to form
What is an example of an amphipathic molecule in the body? Explain where these would be found.
Phospholipids; in the cell membrane
Yttrium has the atomic number 39. Describe how a Yttrium (Y) atom will most likely achieve a stable electron configuration.
The Yttrium atom will give away 3 of its valence electrons to become stable
Describe the partial charges on a water molecule (which atom is δ⁻ and which is δ⁺) and indicate where hydrogen bonds form between adjacent water molecules.
Hydrogen becomes partially negative due to the pull on the shared electrons closer to oxygen's nucleus. Oxygen becomes partially negative.
Hydrogen bonds occur between the hydrogen atom of one water molecule and oxygen of a different water molecule.
If a base gains H⁺ ions, does the solution become more acidic, more basic, or more neutral? Explain briefly
The base would become more acidic. H+ ions will increase the acidity. While it is "becoming more neutral" the base has gained more H+ ions which will cause the value of the pH to go down meaning it will be getting more acidic.
What are the 5 properties of water?
Water is less dense as a solid
Water has a high specific heat
Water has high heat of vaporization
Water has cohesion on high surface tension
Water is the universal solvent
Rank the bonds based on strength from weakest to strongest.
1) Hydrogen
2) Ionic Bond
3) Polar Covalent Bond
4) Nonpolar Covalent Bond
Compare silicon’s likely bonding behavior to carbon’s using valence electrons; predict the types of bonds silicon commonly forms and why its biochemical role is limited relative to carbon
Silicon has 4 valence electrons allowing it to form up to four bonds
Silicon will only form stable single bonds and unstable double and triple bonds
Silicon-Silicon bonds are weaker due to the size of the actual atoms compared to carbon. this makes it more difficult to for silicon to form large complex chains.
Explain at the molecular level why ice is less dense than liquid water and how this property protects aquatic life in a pond during winter.
Hydrogen bonds will break when water starts to freeze which makes the molecules less compact. This protects aquatic life because it could freeze from the bottom killing all life
A soil buffer is tested against repeated acidic rainfall. Describe the qualitative pH data trend (buffered vs. unbuffered soil) that would demonstrate successful stabilization.
The data would show that the buffered soil would keep the pH near a constant value or would decrease slowly. The unbuffered soil would show a huge decrease in pH causing the soil to become significantly more acidic compared the buffered soil.
What is the "law" that allows Wood Frogs to freeze during the winter?
Free radicals happen when our bodies are exposed to radiation. The problems is when free radicals cause damage to DNA which can cause harmful mutations.