BIO 140 Exam 2
4 classes of biological molecules:
1. Carbohydrates 2. Lipids 3. Proteins 4. Nucleic acids
7 functional groups:
1. Hyrdoxyl 2. Carbonyl 3. Carboxyl 4. Amino 5. Sulfhydrl 6.Phosphate 7. Methyl
Compared to a carbon atom with only single covalent bonds, a carbon with a double bond
C. Has a planar configuration of its electron orbitals rather than a tetrahedral configuration
Isomers
Compounds with the same molecular formula but different structures and properties.
Which of the following ionizes completely in solution and is considered to be a strong base (alkali)?
E. NaOH
Glycerol
a three carbo alcohol with a hydroxyl group attached to each carbon
Which of the following solutions would require the greatest amount of base to be added to bring the solution to neutral pH?
a. Gastric juice at pH 2
Which of the following statements correctly describes cis-trans isomers?
a. They have variations in arrangement around a double bond
The central carbon in amino acids is asymmetric in all amino acids except:
a. glyclene
Fats and Oils have hydrocarbons components that make them hydrophobic because they are
a. non polar substances that repel water molecules
Is this molecule soluble in water?
a. yes
A strong acid like HCL
a.) ionizes (dissociates) completely in a aqueous solution.
Cholesterol
an important steroid, is a component in animal cell membranes.
Phospholipids
are essential for cells because they are the major structural component of cell membranes
Alpha Polymers
are helical in shape
Hydrolysis Reaction
are how polymers are disassembled to monomers. A reaction that uses a water molecule to break the covalent bond between monomers and is the reverse of the dehydration reaction.
Steroids
are lipids characterized by a carbon skeleton consisting of four fused rings.
Hydrocarbons
are organic molecules consisting of only carbon and hydrogen
Amino acids
are organic molecules with both carboxyl and amino groups differ in properties, due to side chains (R groups) linked by peptide bonds
Macromolecules
are polymers, built from monomers are large molecules composed of covalently bonded atoms
Monomers
are small repeating units that serve as the building blocks of larger molecules, polymers
Beta Polymers
are straight in shape
Lipids
are the one class of large biological molecules that DO NOT form polymers repel water fats, phospholipids, and steroids.
Monosaccharides
are the simplest carbs, sugar monomer building blocks serves as major fuel for cells and as raw material for building molecules
Polypeptides
are unbranched polymers built from the same set of 20 amino acids
An atom has 6 electrons in its outer valence shell. How many unpaired electrons does it have?
b. 2
How many structural isomers are possible for a substance having the molecular formula C4H10?
b. 2
What is the maximum number of covalent bonds an element with atomic number 8 can make with hydrogen?
b. 2
A compound contains hydroxyl groups as its predominant functional group. Which of the following statements is true concerning this compound?
b. It should dissolve in water
Which group of large biological molecules is not synthesized via dehydration reactions?
b. Lipids
The Miller-Urey experiment
b. demonstrated that amino acids and other organic molecules form under conditions that may have existed on Earth before life began.
Testosterone and estradiol are
b. structural isomers of each other
What determines whether a carbon atom's covalent bonds to other atoms are in a tetrahedral configuration or a planar configuration?
b. the presence or absence of double bonds between the carbon atoms and other atoms.
Organic Chemistry is currently defined as
b. the study of carbon containing compounds
The general structure of amino acids are shown in this figure what functional groups are highlighted in salmon and yellow, respectively?
c. Amino and carboxyl
Which of the following is not a way in which carbon chains can vary in organic compounds?
c. Number of covalent bonds to the carbons in the chain
Amino acids are acids because they always process which functional group?
c. carboxyl
Which two functional groups are always found in amino acids?
c. carboxyl and amino
Why are human enzymes that digest starch unable to digest cellulose?
c. cellulose has beta linkages, starch- digesting enzymes cleave only alpha glycosidic linkages.
If the pH of a solution is increased from pH 5 to pH 7, it means that the
c. concentration of OH- is 100 times greater than what it was at pH 5.
Fatty acids
composed of fats, consists of a carboxyl group attached to a long carbon skeleton
Starch
consists entirely of glucose monomers, plants store it. simplest form of starch is amylose.
Functional protein
consists of one or more polypeptides precisely twisted, folded, and coiled into a unique shape.
Fats
constructed from two types of smaller molecules: glycerol and fatty acids.
How many electron pairs does carbon need to share in order to complete its valence shell?
d. 4
Which of the following hydrocarbons has a double bond in its carbon skeleton
d. C2H4
What functional group is commonly used in cells to transfer energy from one organic molecule to another?
d. phosphate
Which of the following is a false statement concerning amino groups?
d. they are non polar.
Which polysaccharide has the greatest number of branches?
e. Glycogen
Research indicates that ibuprofen, a drug used to relieve inflammation and pain, is a mixture of two enantiomers; that is, molecules that
e. are mirror images of one another
Buffers are substances that help resist shifts in pH by
e. both donating H+ to a solution when bases are added, and accepting H+ when acids are added.
If the pH solution is decreased from 9 to 8, it means that the
e. concentration of H+ has increased tenfold (10x) and the concentration of OH- has decreased to one-tenth (1/10) what they were at pH 9.
All lipids
e. do not dissolve well in water
Given a chemical formula for an organic molecule, C6H12O6, one can usually deduce its
e. molecular weight and solubility in water
How many isomers can you make from the molecular formula C6h1206?
e.) more than 6
Disaccharide
formed when a dehydration reaction joins two monosaccharides, this covalent bond is called a glycosidic linkage.
Secondary structure
found in most proteins, consists of coils and folds in the polypeptide chain.
Structural Isomers
have different covalent bonding arrangements of their atoms
Unsaturated fatty acids
have one or more double bonds between carbons along the carbon skeleton liquid at room temperature
Saturated fatty acids
have the maximum number of hydrogen atoms possible and no double bonds with the long carbon skeleton solid at room temperature
Cis-trans isomers
have the same covalent bonding but different in spatial arrangements a double bond.
Carbohydrates
include simple sugars and the polymers of sugars
Essential fatty acids
include the unsaturated omega-3 fatty acids, required for normal growth in children. supplied through diet
Protein
is a biologically functional molecule that consists of one or more polypeptides
Tertiary structure
is determined by interactions among various side chains (R groups)
Chitin
is found in the exoskeleton of anthropods, similar to cellulose. Provides structural support for the cell walls of many fungi.
Insoluble fiber
is when the body cannot hydrolyze beta linkages, therefore cellulose cannot be broken down into individual glucose molecules
Polymer
long molecule consisting of many similar or identical building blocks linked by covalent bonds
Cellulose
major component of tough cell well that encloses most plant cells, most abundant organic polymer on earth. is a polymer of glucose, but the glycosidic linkages differ.
Enantiomers
mirror images of one another
Dehydration reaction
occurs when two monomers form a covalent bond together and release a water molecule in the process
Primary structure
of a protein is its unique sequence of amino acids
Polysaccharides
polymers composed of many sugar building blocks, have storage and structural roles
Hydrogenation
process of converting unsaturated fats to saturated fats by adding hydrogens to the hydrocarbon chain
Quaternary structure
results when a protein consists of multiple polypeptide chains.
Enzymes
speed up chemical reactions (biological catalysts)
Base
substance that decreases the H+ concentration of a solution
Acid
substance that increases the H+ Concentration of a solution
Triacylglycerol
three fatty acids join to glycerol by a ester linkage
Trans fats
worse than saturated fats diet rich in saturated fats contributes to cardiovascular disease, atherosclerosis.