All, without exception, nucleic acids contain which five elements?
C
H
O
P
N
Why do the rings in nucleic acids differ from others?
they contain nitrogen
What is the function of 1-6 linkages?
branching out
What linkage does amylose have? amylopectin? glycogen?
1-4 alpha linkages
1-6 alpha linkages
1-6 and 1-4
What is the catch with structural polysaccharides?
they cannot be hydrolyzed by the organisms that make them
What are the two shapes of proteins?
fibrous (relatively straight and long)
- usually just primary, secondary, and quaternary
globular (spherical)
- has all four levels
What are the three classification systems of proteins?
based on:
- levels of structure
- composition
- function
What are the protiens based on levels of structure?
fibrous proteins: exhibit primary and secondary structure; somes quaternary; insolubale; stable; form tough structures
globular proteins: exhibit primary, secondary, tertiary, and sometimes quaternary; arranged so that the R-groups are on the inside and the ones on the outside are hydrophilic
What are proteins based on composition?
simple proteins: composed of only amino acids in a polypeptide chain
Conjugated proteins: composed of one or more polypeptide chains plus a non-amino acid component called a co-factor; the cofactor has to be there for the protein to function
What are proteins based on function?
structural
contractole (muscle)
defensive
transport
hormones
toxins
storage
receptor proteins
enzymes
What are the disaccharides?
maltose= glucose + glucose
lactose= galactose + glucose
sucrose= fructose + glucose
What does sucrose do?
transform form of sugar in the plant
-storage of carbs in larger sizes
what is lactose?
milk sugar
What are oligosaccharides?
a short chain of 3 - 100s of monosaccharide molecules joined together via glycosidic bonds
- usually linked to some other molecule (lipid, protein)
- most common location: poking out surface of plasma membrane
What are the two basic functions of oligosaccharides?
recognition
adhesion
What is linkage?
a designation of which carbon atoms in adjacent monosaccharide subunits are bonded together; can also indicate whether in alpha or beta form
What are the two forms of starch?
amylose
amylopectin
What are examples of lipids?
fats
oils
waves
phospholipids
carotenoids
steroids
What are the components of phospholipids?
one glycerol
two fatty acids
one phosphate (may/ may not include an organic group attached to the phosphate)
What are the three classifacations of amino acids on basid of chemical characteristics of the R group?
nonpolar
polar but uncharged
electrically charged (acidic or basic)
What do proteins differ in?
- total number of amino acids (size); each type of protein contains a specific number of amino acids
- relative quantities of each specific type of amino acid
- specific sequence (order) of amino acids
- specific 3D shape
What are the subunits of DNA?
deoxyribonucleotides
What is the 5' end?
end where the phosphate group is not attached to another nucleotide
What is a 3' end?
end where sugar of nucleotide is not linked to another nucleotide
How many hydrogen bonds form with adenine?
two
How many hydrogen bonds form between guanine and cytosine?
three
Who proposed the structure of DNA?
alpha double helix
Watson and Crick (+ Rosalind Franklin)
DNA molecules differ in?
number of base pairs
relative quantities of each specific base pair
specific sequence (order) of base pairs
What is the function of DNA?
stores genetic info in the sequence of genes
What are the alternative forms of DNA?
single stranded v. double stranded
linear vs. circular
3D structures
What is the difference between organic and inorganic?
organic contains carbon
inorganic may contain carbon iin a very energy poor state
All chemical reactions in the cell occur where the reactants __.
dissolve in water
Why is water a very good solvent?
its a polar molecule
Oxygen has a partial negative charge, while hydrogen has a partial positive charge, enabling attraction to other compounds.
What are two other important functions of water?
tranfsport
it acts as a lubricant to decrease friction
Hydrolysis can only occur if __.
the molecule is combined through dehydration reactions.
What are the benefits of linking monosaccharides togehter?
decreases amount of material in cell, lowering the concentration of dissolved material in the cell
What do lipids consist of? Which are dominant?
C
H
O
and sometimes P and N
Lipids are insoluble in __, but soluble in __.
water
organic solvents
In fats and oils, what does glycerol not contain? How many carbons are usually present in hydrocarbon chains?
double bond
14-22
True or False: If a molecule has even a slight charge, it will dissolve in water.
true
What is the function of the phosphate group in a phospholipid?
hydrocarbon tails?
interact well water water due to charge (polar/ hydrophilic)
tails are hydrophobic and are away from the water
What are steroids?
four-fused rings of carbon; the sharing of carbons enables fusion
Animal hormones are one of two types:
steroids
proteins
What makes steroids different?
the attachments to the ring
What is the solubility characteristic of steroids?
rings don't dissolve in water (hydrophobic)
the only hydrophilic substance is the -OH group
Explain cholesterol/
cholesterol: major function of animal membranes ONLY
liver makes it
starting point for making other steroids
animal hormones
vitamines
What are the elements in proteins?
C
H
N
O
and sometimes sulfur
Peptide bonds link two __. Are they straight or branched?
amino acids
straight
Which amino acid usually starts the chain?
methionine
How do the ends of the chains in polypeptides differ?
N-terminus
C- terminus
Explain the linkages in each stage of protein structure?
Primary: carboxyl and amino acid (peptide bond)
Secondary: hydrogen bonding between carboxyl and amino acid
Tertiary: bonds between the side chains of same polypeptide, giving it an folded, 3D shape
Quaternary: bonds between two or more polypeptide chains
Do all proteins have:
primary structure?
secondary structure?
tertiary structure?
quaternary?
yes
yes
no
no
In DNA, which components are responsible for bining the nucleotide together?
phosphates and sugar--> phosphodiester linkage
What are the purines?
adenine and guanine
What are the pyrimidines?
cytosine and thymine
Exlain:
- single stranded DNA? - double stranded DNA?
viruses usually contain
most common form
Explain:
- linear DNA.
- circular DNA.
Linear common in most organisms
Bacteria, mitochondria, and chloroplasts contain circular DNA.
What are the 3D Structures of DNA?
B-DNA: most common; right-handed helix/ set number of base pairs per turn
A- DNA: right- handed helix; higher set of base pairs per turn exists
Z- DNA: same base pair number per turn as B-DNA; very temporary; left-handed helix
