Test 1 (also) Flashcards
Important Functional Groups
Hydroxyl Carbonyl Carboxyl Amino Sulfhydryl Phosphate
Macromolecules
most macromolecules are polymers, built from monomers
Three of the classes of life’s organic molecules are polymers
carbohydrates
proteins
nucleic acids
polymer
a long molecule consisting of many similar building blocks called monomers
Synthesis of polymers
monomers form larger molecules by condensation reactions called deyhdration reactions
Dehydration
removes a water molecule, forming a new bond
Hydrolysis
breaks down/disassembles polymers
adds a water, breaks a bond
Carbohydates
serve as a fuel and building material
(CH20)n
Include both sugars and their polymers
Can be monosaccharides or polysaccharides
Monosaccharides (structure)
may be linear
in solution they form rings
chem equilibrium b/w linear and ring greatly favors rings
Cellulose
Major component of the tough walls that enclose plant cells
Has more hydrogen bonds than starch
Unbranched beta glucose polymer
Lipids
Diverse group of hydrophobic molecules Are the one class of large biological molecules that do not consist of polymers in a strict sense
Fats
Are constructed from two types of smaller molecules, a single glycerol and usually three fatty acids
Major function is energy storage
Whats type of bond is between glycerol and a fatty acid?
Ester linkage
Why don’t we use starch like plants?
- A gram of fat stores ~9 cal while a gram of carbs stores ~4
- plants can afford to have inefficient fuel because they don’t move
- fats cushion vital organs (ex. kidneys)
- subcutaneous fat insulates the body (ex. whales and seals)
Phospholipid structure
hydrophilic “head” and hydrophobic “tails”
Steroids
characterized by a carbon skeleton consisting of four fused rings
Cholesterol
A steroid
Found in cell membranes
Precursor for some hormones
Proteins (role)
Have many structures resulting in a wide range of functions
- Enzymes
- Structural
- Transport
- Hormones
- Receptors
- Motor proteins
- Defense proteins
Polypeptides
polymers of amino acids
Amino acids
- organic molecules possessing both carboxyl and amino groups
- differ in their properties due to differing side chains (R groups)
Protein (consists of)
one or more polypeptides
Link between amino acids?
Peptide bonds
Primary structure (protein)
determined by peptide bonds
unique sequence of amino acids in a polypeptide
Secondary structure (protein)
exists because of hydrogen bonds
the folding or coiling of the polypeptide into a repeating configuration
includes alpha helix and beta pleated sheet
Tertiary structure (proteins)
can be predicted
is the overall 3-D shape of a polypeptide **driven by hydrophoic interactions **
results from interactions b/w amino groups and R groups
Quaternary structure
not all proteins have this structure
overall protein structure that results from the aggregation of two or more polypeptide subunits
Nucleic Acids (role)
store and transmit hereditary information
genes
-are the units of inheritance
-program the amino acid sequence of polypeptides
-are made of nucleic acids
Two types of nucleic acids
Deoxyribonucleic acid (DNA) Ribonucleic acid (RNA)
RNA (types)
Coding- carries the information from DNA for synthesis of specific proteins
Non-coding- rRNA, tRNA
Catalytic- self-splicing introns, ribozymes, rRNA in ribosomes
Other roles-Metabolite sensing, attenuation of translation, RNA interference (RNAi)
Nucleic Acids (structure)
Exist as polymers called polynucleotides
Nucleotide
Each polynucleotide consists of monomers called nucleotides
- phosphate group
- nucleoside (nitrogenous base and pentose sugar)
DNA double helix
- have two polynucleotides that spiral around an imaginary axis
- phosphates in double helix are charged, which makes them like polar solvents better
- bases are hydrophobic, which forces them to be positioned on the inside
DNA double helix complimentary strands
consists of two antiparallel nucleotide strands
5’ end and 3’ end
5’-GAATTC-3’ has another 5’-GAATTC-3’ complementary to it
The 20 different amino acids in polypeptides exhibit different chemical and physical properties because of different what?
side chains (R groups)
Size of atomic nucleus (relative to shell)
much smaller
How molecules can one water molecule form hydrogen bonds with?
4
What is the bond holding DNA double helix strands together?
Hydrogen bonds
Saturated fatty acid
Contain only single bonds between carbons. Carboxyl group on end
Unsaturated fatty acid
Contain at least one double bond between carbons. Cannot be stacked, liquid at room temp. Carboxyl group on end
Whats the difference between the sugar in DNA and the sugar in RNA?
One less oxygen in DNA (DeOXYribonucleic acid)
Why does water have a high specific heat?
Absorption and release of heat when hydrogen bonds break and form
Enantiomers
Mirror images of one another
Which functional groups can act as acids?
Carboxyl and phosphate
Pyrimidines
- Nitrogenous bases
- Cytosine (C)
- Thymine (T-in DNA)
- Uracil (U-in RNA)
Purines
- Nitrogenous bases
- Adenine (A)
- Guanine (G)
Proteins may be related even when they share as low as ___ % sequence identity
5
Sugar: Monomers, Polymer, Type of Linkage
Monosaccharides, polysaccharides, glycosidic linkages
Lipids: Components, Large molecule, Type of Linkage
Fatty acids, Triacylglycerols, ester linkages
Proteins: Monomers, Polymer, Type of Linkage
Amino acids, polypeptides, peptide bonds
Nucleic Acids: Monomers, Polymer, Type of Linkage
Nucleotides, polynucleotides, phophodiester linkages
Sickle-cell disease
- Results from a single amino acid substitution in the protein hemoglobin
- This change is particularly disrupting to protein structure because of the nature of amino acids
- Better protected against malaria
What determines protein conformation?
- Solvent, temperature and pH
- Interactions between amino acid side-chains
Denaturation
When a protein unravels and loses its native conformation
Renaturation
Takes a denatured protein and returns it to a normal protein
Chaperonins
Protein molecules that assist in the proper folding of other proteins
Phospholipids
- Have only two fatty acids linked to glycerol
- Have a phosphate group instead of a third fatty acid
Enzymes
A type of protein that acts as a catalyst, speeding up chemical reactions
Amino acids linked by?
peptide bonds
Glycosidic links are formed between carbon atom 1 and ??
Carbons 2, 4, or 6
Disaccharides
two monosaccharides joined by glycosidic linkage
Starch and Glycogen
both are storage polymers consisting entirely of alpha glucose monomers
Starch
found mostly in plants (major storage form)
Glycogen
mostly found in animal muscles and liver (major storage form of glucose in animals), more branched glucose monomers than starch
Cellulose
unbranched polymer of beta glucose
has more hydrogen bonds than starch
Chitin
important structural polysaccharide
- found in exoskeleton of anthropods
Cohesion
Helps pull water up through microscopic vessels of plants
Surface tension
related to cohesion
greater in water than most liquids
Moderation of Temperature
- water moderates air temperature by absorbing heat from air that is warmer and releasing the stored heat to air that is cooler
- has a high specific heat
Why does water have high specific heat?
- allows it to minimized temp fluctations to within limits that permit life (heat absorbed when H bonds break, released when H bonds form)
- water changes temp less when absorbs or looses a give amt of heat
Evaporative cooling
due to waters high heat of vaporization
-Allows water to cool a surface
Solvent of Life
- versatility due to polarity
- can for aq solns
- not a universal solvent (which is good!)
