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.