BIOCHEMISTRY QUIZ REVIEW Flashcards
What are atoms?
Atoms are defined as the smallest unit of matter that forms a chemical element.
What are atoms composed of?
They are composed of subatomic particles. The nucleus of an atom contains protons and neutrons. The shells contain electrons.
Maximum number of electrons in shell order
2, 8, 8, 18, 18, 32,32
What are elements? + Examples
Substance that contains only one type of atom. Silver, Gold, Sodium
Atomic number represents
Number of protons or electrons
Atomic mass
Average weight of an atom. Atomic number (protons) subtract atomic mass is neutrons
Can individual atoms’ mass vary?
Yes. For an example Carbon can all have different mass. The mass listed on periodic tables are just the average weights.
What are isotopes?
Elements that have the same number of protons but different number of neutrons.
If isotopes are unstable and produce radiation, what are they called?
They are called radioactive.
What are compounds?
When two or more elements are combined by covalent or ionic bonding
Examples of compounds?
NaCl (salt), KI (Potassium Iodide)
What is Ionic bonding? (4)
- Forms between metal and non-mentals.
- Elements will lose or gain electrons.
- Metals lose electrons while non-metals gain electrons
- TRANSFER of electrons occurs.
What is covalent bonding? (4)
- Forms between two non-metals.
- Bond forms from molecules.
- Atoms do not become charged.
- SHARING of electrons occurs.
What are acids?
Compounds that dissociate (break apart) in water and release Hydrogen ions. Ex. HCl
What are bases?
Compounds that dissociate in water and release Hydroxide ions. Ex. NaOH
What is a pH?
Quantitative measure of how acidic or basic a solution is
How does the pH scale work?
Scale ranges from 0 to 14. Lower the number the more acidic; lower than 7 is acidic. Higher the number the more basic. pH of 7 is neutral.
What are buffers?
To keep pH levels from changing, cells contain BUFFERS. It is a chemical that can take excess hydrogen ions or excess hydroxide ions.
What are common buffers?
Acetic acid & Carbonic acid-bicarbonate.
Inorganic compounds (3)
- Ionic bonding (mostly) so metal and non-metal.
- Smaller number of atoms
- Associated with non-living elements.
Organic compounds
- Covalent bonding (always) so non-metal and non-metal.
- Larger number of atoms
- Associated with living elements.
What type of bond is water?
Water is linked through covalent bonds but hydrogen bonds are formed
What is a polar molecule?
Molecule that is slightly positive and slightly negative.
Why is water polar?
They have an uneven distribution of electrons
Because water is polar, what type of bonds do water form?
Hydrogen bonds
How do hydrogen bonds occur?
When a partial positive hydrogen is attracted to a partial negative oxygen.
Are hydrogen bonds strong?
No. It is represented by a dotted line because it can be easily broken.
How is hydrogen bonding liquid at room temperature?
It has a low freezing point and a high boiling point allowing it to be liquid at room temperature.
How do oceans remain at a constant temperature, hydrogen bond?
Water has a high heat capacity. It absorbs heat quickly and warms up and releases heat slowly before freezing
Water is a universal _____
Universal solvent. It dissolves solutes and dissociates substances.