Test 1 Ch2 Flashcards
what are six most common elements?
Carbon, hydrogen, nitrogen, oxygen,
phosphorous and sulfur
structure of an atom
Nucleus: neutrons and protons (positively
charged)
Cloud of orbiting electrons (negatively
charged)
what are covalent bonds?
Atoms share electrons in outer most shell to form molecules. All covalent bonds are strong. The strongest bonds.
what are two types of covalent bonds?
-Non-polar covalent bonds
Equal attraction or electronegativity for electrons
-Polar covalent bonds
Unequal attraction for electrons
Due to difference in electronegativity
single bonds
2 shared electrons and most free rotation
double bonds
4 shared electrons
what are noncovalent bonds?
Non-covalent bonds occur when atoms are
associated, but do not share electrons
Non-covalent bonds are weak, but the sum of non-covalent bonds can be strong
What are the four noncovalent bonds?
Ionic bonds
Hydrogen bonds (very weak)
Hydrophobic interactions
Van der Waals forces
what are ionic bonds?
ionic bonds form between ionized atoms
Ionization means one atom donates one or more electrons, while the
other atom accepts those electrons
Cation: atom that donates electron, has positive charge
Anion: atom that accepts electron, has negative charge
what is electrostatic attraction?
Opposite charged, inonized atoms are attracted to each other by
electrostatic attraction
Electrostatic attraction is strongest between fully ionized atoms such as Na+
and Cl-. Partially charged atoms are more weakly attracted. Most biological
ionic interactions are between partially charged atoms
what are hydrogen bonds?
-Interaction between a positively
charged hydrogen ion in one
molecule and negatively charged
atom in another (example of a strong
electrostatic dipole)
-Occurs between highly polar
molecules with hydrogen
- Any molecules with polar covalent
bonds can form H-bonds with water
Individually, very weak bond, 16.7
kJ/mole
- Indicate H bonds with vertical lines
what are hydrophobic reactions?
-fear of water
Occurs w nonpolar molecules (try to bond with each other to escape water) want to dissociate with water such as fatty acid tails.
Van Der Waals
Between any two atoms
Consist of dipole-dipole and dispersion forces
As two atoms get closer, fluctuation in electric
charges increase attractions, too close repel
Very weak
Important in protein structure when proteins fit
closely together, sum of all Van der Waals can be
strong
what is the structure of water?
-water is polar
-forms hydrogen bonds
- has cohesive and adhesive
it effects solubility of other molecules (any molecule charged and polar are hydrophilic)
Acids
donate protons
Base
Accepts protons
pH measures?
concentration (moles/L) of pH-log
almost all molecules in cells are based on
carbon carbon bonds = organic molecules
carbon can form covalent bonds with 6 different atoms?
C-N
C-O
C-H
C-P
C-C
C-S
saturated
Single C-C bond
Single pair of electrons shared
Each C bound to three other
atoms –Saturated
Free rotation
unsaturated
Double C-C bond
2 pairs of electrons shared
Each C bound to two other atoms
– unsaturated
Fixed – no rotation
Monosaccharides form
polysaccharides
fatty acids form
fats and lipids
amino acids form
proteins and polypeptides
Nucleotides form
nucleic acids
covalent bonds between subunits formed by:
condensation reaction (dehydration synthesis) -molecule of water expelled
Covalent bonds are broken by:
hydrolysis reaction -molecule of water consumed
What do both condensation and hydrolysis reaction requires?
-Enzymes
-Condensation reaction always requires
energy input
Macromolecules are formed by:
adding subunits to
one end of growing polymer in a specific order
Monomer
monosaccharide (simple sugar)
-All have formula CH2O..
hydroxyl and carboxyl groups are
polar, thus water soluble
polymer
disaccharide(2) or polysaccharide (many) linked together by glycosidic bonds
Mono and disaccharide (macromolecules) function
immediate energy
source for cells
polysaccharide(macromolecules) function
-Starch: energy storage in plants
-Glycogen: energy storage in animals
(liver and muscle cells)
- Cellulose: structural part of cell wall in plants
what is monomers?
a small, basic molecular unit that can bind chemically to other similar molecules to form a larger structure called a polymer. Monomers are the building blocks of polymers, which are complex molecules with repeating structural units.
Lipids (macromolecules)
-Have hydrophilic carboxylic head
* Hydrophobic hydrocarbon tail
* Saturated, no double
bonds
* Unsaturated, one or more
double bonds
* Does not form a true polymer
* All lipids/fats are hydrophobic
phospholipid (lipid)
Has two fatty acid tails (one unsaturated)
- Have a glycerol group, phosphate group and a hydrophilic head (likes water because polar group + phosphate group)
-Big component of cell membrane formed by condensation rxns
Protein (Macromolecule)
-They’re long polymers of amino acids linked by peptide bonds
know how to draw
Peptide bonds
in proteins, amino acids are joined together by an amide linkage called a peptide bond.
-Peptide bonds formed by condensation rxns
R groups
20 total aminos differ by their R groups
Types of R groups:
-Charged (acidic or basic): They can gain or lose e- and their charge is dependent on the pH of the environment
-Uncharged, polar: interacts with water
- Non-polar: Doesn’t interact with water
Covalent bonds between subunits (monomers) form
Macromolecules (polymers)
-Noncovalent bonds cause many macromolecules to fold
-Noncovalent bonds mediate interactions between molecules
Macromolecules are polymers built from subunits (monomers) covalently
inked together by ___________________ reactions.
condensation
Name the specific covalent bond formed between monomers (subunits) of:
a. Amino acids:
b. Monosaccharaides:
c. Nucleotides
a. Peptide bonds
b. Glycosidic bonds
c. Phosphodiester bonds
Polysaccharide function
energy storage and structural part of cell wall
monosaccharide function
immediate energy source
Nucleic acids function
responsible for storage, transmission, and expression of genetic information
Phospholipids function
major components of cell membranes
Proteins function
catalyze biochemical rxns, provide structural support, regulate cellular processes, transport molecules, facilitate immune responses
draw structure of amino acid pH 7 label alpha carbon, amino group. carboxyl group, r group
draw it
Draw the structural formula of a tripeptide (3 amino acids linked by peptide
bonds). Include 3 different R group structures that are likely to found on
the outside of a water soluble protein. Label/name each R group. Draw a
box around one peptide bond
Draw this
Draw the structural formula of the monosaccharide glucose in the ring
structure.
Draw this
Draw the structural formula of a 10 carbon fatty acid with one unsaturated
bond. Label the hydrophilic and hydrophobic parts of the fatty acid
draw this
What part of the fatty acid structure makes it an “acid”?
The carboxyl group because it can donate an H+
Draw the general formula of a phospholipid. Include the following labels:
fatty acid tails, glycerol group, phosphate group, hydrophilic group.
draw this
Identify each of the molecules below as: monosaccharide, disaccharide,
polysaccharide, nucleic acid, nucleotide, amino acid, polypeptide (protein),
fatty acid or lipid.
do this on papers
Determine whether the following statement is true or false:
In cells, electrostatic attractions are stronger than covalent bonds.
This statement is
false
Which of the following covalent bonds is relatively nonpolar?
Choose one:
A. bond between carbon and hydrogen, –C–H
B. bond between nitrogen and hydrogen, –N–H
C. bond between oxygen and hydrogen, –O–H
A.
-An atom of carbon and an atom of hydrogen attract electrons fairly equally, so the C–H bond is relatively nonpolar. Both oxygen and nitrogen attract electrons more strongly than hydrogen, so these bonds would be polar. Polar chemicals with –OH and/or –NH groups are commonly soluble in water, whereas hydrocarbons of gasoline and oil are not.
What type of bond is formed when one atom donates electrons to another atom?
ionic
Carbon, which has four electrons in its outer shell (with a capacity of eight electrons), can form a maximum of how many covalent bonds with other atoms?
4
Which type of covalent bond allows for rotation about the bond axis?
single
Regarding acids, bases, and pH, which of these statements is true?
Choose one:
A. Substances that release protons when they dissolve in water are termed bases and result in a pH lower than 7.
B. Substances that release protons when they dissolve in water are termed bases and result in a pH higher than 7.
C. Substances that release protons when they dissolve in water are termed acids and result in a pH higher than 7.
D. Substances that release protons when they dissolve in water are termed acids and result in a pH lower than 7.
D
On the basis of weight, which is most abundant in a living bacterial cell?
Choose one:
A. inorganic ions
B. macromolecules
C. fatty acids
D. proteins
E. water
E. water
Which bond term describes a covalent bond in which electrons are shared unequally?
Polar bonds
Which type of bond is the strongest in cells?
covalent
Which term best describes a fatty acid?
Choose one:
A. amphipathic
B. hydrophilic
C. hydrophobic
D. hydrodynamic
A. amphipathic
-Fatty acids contain both hydrophilic (water-loving) and hydrophobic (water-hating) regions, a property that makes them amphipathic and that allows the lipid bilayer to spontaneously form. The interior of the plasma membrane is nonpolar (and thus hydrophobic) and both sides of the plasma membrane are polar (and thus hydrophilic).
What type of bond is formed when two atoms share electrons?
E. covalent bond
