Topic 2 Cell Chemistry Flashcards
What are Chemical Bonds?
electrostatic forces between positively charged protons of one atom and negatively charged electrons of another atom that hold these atoms together within a molecule or between molecules
What are intramolecular bonds? name some types of intramolecular bonds (4)
- hold atoms in the same molecule together
- Ionic bonds
- Covalent bonds
- Hydrogen bonds
- Hydrophobic interactions
what are intermolecular bonds? name some types of intermolecular bonds (4)
- form between two different molecules
- Hydrogen bonds
- Hydrophobic interactions
- Electrostatic (ionic) forces
- Van der Waals forces
why do bonds form?
bonds form between atoms to achieve a more stable situation
When are atoms the most stable? (2)
- ) Electrons in lowest possible energy levels
2) Outermost energy level (valence shell or level) is filled to its maximum (2 or 8)
**To achieve this stability, most atoms most gain, lose or share electrons thus forming bonds and larger structures referred to as molecules
look at slides 5-10
all chemistry review :)
name the 5 compound types and state their charge/polarity, type of bonds, other info
- Ionic – composed of all/mostly ionic bonds; generally water soluble to point of saturation (hydrophilic)
- Polar – composed of all/mostly polar covalent bonds; generally water soluble (hydrophilic)
- Nonpolar - composed of all/mostly non polar covalent bonds; not water soluble (hydrophobic)
- Amphipathic – composed of part hydrophilic (ionic and/or polar) and part hydrophic (non polar) regions; on part water soluble, other part not
- Solutions – solute and solvent
describe a hydrogen bond
“weak” bond that forms due to electrostatic interactions between hydrogen atoms (with positive polarity) and more electron-attracting (electronegative) atom (negative polarity)
Hydrogen has positive polarity because……
Hydrogen has positive polarity because it in polar covalent bond with larger, more electronegative atom (ie, oxygen or nitrogen)
- ) Multiple hydrogen bonds impart considerable (stability/instability) to molecules
- ) Plays (major/minor) role in the solubility and other properties of water
- ) Play (major/minor) roles in the biological properties of proteins
- ) stability
- ) major
- ) major
* slides 13 and 14)
describe hydrophobic interactions
Weak bonds that occur when nonpolar molecules, or nonpolar regions of molecules, associate tightly in a polar solvent (ie, water); non polar molecules disrupt hydrogen bonding among water molecules so they “squeezed together or pushed” by water molecules to minimum their volume (therefore disrupting minimum number of hydrogen bonds)
why are hydrophobic interactions important? (3)
play important roles in…
- ) enzymes binding substrates
- ) protein conformation
- ) stabilization of RNA and cell membranes
what are van der waal forces?
weak attractive forces that occur between atoms when they become closer than 3–4 Å
van der waal forces occur due to…
temporary polarities in atoms and molecules
why are van der waal forces important?
- Play important roles in enzymes binding substrates and protein–nucleic acid interactions
- Play an important role in membrane fluidity
slides 18-20
Look at :)
what are monomers?
small molecules that are the building blocks of larger molecules
what are polymers?
larger molecules composed of covalently bonded similar or identical monomers
what are some inorganic molecules?
Water
Salts
Acids/Bases/Buffers
what are some organic molecules?
Carbohydrates Lipids Polypeptide/Proteins Nucleic Acids Others *slide 23
water is a polar molecule. this accounts for for of waters properties. name a few (4)
Can form hydrogen bonds and other bonds
Good solvent for polar and ionic molecules
High Specific heat
Exhibits cohesion and adhesion
describe salts
ionic compounds consisting of a cation and an anion held together by an ionic bond
Salts often ______ in water (a polar solvent) into their respective ____
dissociate; ions
describe acids
Proton donors; increase concentration of H+ ions in a solution
describe bases
proton acceptors; decrease the concentration of H+ ions in a solution
describe buffers
compounds that resist changes in pH by sometimes behaving like an acid, and sometimes like a base; found in all cells
what are lipids? give examples and describe properties and function (4)
- fats, oils, sterols, other
- Non Polar compounds
- Hydrophobic
- Play crucial roles in most membrane and as energy storage molecules
what are carbohydrates? give examples and describe what makes them up and a function
- monosaccharides,polysaccharides
- Polymers of sugar units bonded together by glycosidic bonds
- Play important roles in cell walls and as energy storage molecules
describe proteins and state what makes them up
- polymers of amino acids
- Most abundant macromolecules in cells
- Found throughout cell
- Have important structural and enzymatic roles
what makes up nucleic acids? what are the two forms?
-polymers of nucleotides
-Two forms (RNA and DNA)
[RNA]»>[DNA]