Question 1

Proteins are chains of ______ that sometimes function as________.

Accepted Answer

A)  disaccharides; cell wall
B)  amino acids; enzymes
C)  lipids; energy compounds
D)  glycogen ; enzymes B

Question 2

Describe the chemical composition,type/structure and function for the following complex organic molecules: carbohydrates,lipids,proteins,DNA and RNA

Accepted Answer

Carbohydrates are simple sugars or polymers known as polysaccharides such as starch,glycogen and cellulose. The carbon atoms may be associated with alcohols or a ketone or aldehyde group. Microbes use carbohydrates for immediate energy,storage of energy and cell wall components.
Lipids are organic molecules that are insoluble in water. Many are polymers composed of glycerol bound to two or more fatty acids. They include fats,phospholipids and steroids. They are used for energy storage and cell membrane components.
Proteins consist of chains of amino acids linked by peptide bonds. They form part of the structure of all cellular components and act as enzymes and defense molecules.
DNA and RNA are composed of chains of nucleotides (formed of nitrogenous base,sugar,phosphates). DNA molecules form double stranded helixes. RNA is usually single stranded. DNA and RNA serve as the genetic material (information encoding proteins)for all life forms and play a role in genetic expression as well.

Question 3

Food consists of molecules with lots of energy stored in their chemical bonds. What is true about how microorganisms use nutrients?

Accepted Answer

A)  When microorganisms break the chemical bonds in nutrients, they release energy.
B)  It takes microorganisms more energy to break the bonds in nutrients than are released.
C)  All energy that microorganisms receive from nutrients comes from anabolism.
D)  Microorganisms break down hydrogen bonds to release electrons as energy. A

Question 4

Amino acids in a protein are joined together by _____.

Accepted Answer

A)  peptide bonds
B)  hydrogen bonds
C)  phosphodiester bonds
D)  tertiary bonds

Question 5

Reactions in which molecules are degraded and energy is released are best termed _____.

Accepted Answer

A)  anabolic
B)  catabolic
C)  metabolic
D)  exerbolic

Question 6

A nucleic acid has a "backbone" consisting of:

Accepted Answer

A)  nitrogenous bases
B)  sugars
C)  phosphates
D)  b and c are correct

Question 7

Phospholipids:

Accepted Answer

A)  have a charged phosphate group that can mix with water and insoluble fatty acids.
B)  can serve as hormones.
C)  always remain liquid at room temperature.
D)  form straight chains in water.

Question 8

Describe the formation and importance of a hydrogen bond. Why is water the universal dissolving medium (e.g.,solvent)of life? Name two roles water plays in cells.

Accepted Answer

The answer of Describe the formation and importance of a...

Question 9

The pH scale is used to specify the acidity or alkalinity of a solution.Which of the following statements is true?

Accepted Answer

A)  Stomach acid has a pH around 10.
B)  Neutral solutions, like water, have a pH of 10.
C)  A solution with a pH of 12 has 10 times less protons than a solution with a pH of 11.
D)  A strong base will have a pH less than 10.

Question 10

Which of the following is not a colloid?

Accepted Answer

A)  salt water
B)  gelatin desserts
C)  agar plates used to grow microorganisms
D)  fluid in cells

Question 11

Which is a FALSE statement about chemical reactions?

Accepted Answer

A)  Catabolic reactions are exergonic and release energy.
B)  Polymerization and the building up of large molecules is a catabolic reaction.
C)  Anabolic reactions require energy.
D)  Energy is stored in the form of chemical bonds.

Question 12

Organic molecules with the same molecular formula but different structures are:

Accepted Answer

A)  elements
B)  isotopes
C)  isomers
D)  anions

Question 13

Carbohydrates do not include which of the following?

Accepted Answer

A)  Glucose
B)  Starch
C)  Cellulose
D)  Sterols

Question 14

Molecules that contain mixtures of different elements are called _____.

Accepted Answer

A)  isotopes
B)  atoms
C)  ions
D)  compounds

Question 15

Electrons have a _______ charge and are found in the _________.

Accepted Answer

A)  positive; inner electron shell
B)  positive; outer electron shell
C)  negative; nucleus
D)  negative; outer electron shell

Question 16

In order to become an ion,an atom of chlorine must _____.

Accepted Answer

A)  gain an electron
B)  form a covalent bond
C)  lose an electron
D)  form a hydrogen bond

Question 17

Which of the following statements about solutions is FALSE?

Accepted Answer

A)  The solute is the substance dissolved in a solvent.
B)  Left alone on a counter, a solution will separate out.
C)  Solutes can consist of atoms, ions or molecules.
D)  In cells, water is typically a solvent.

Question 18

Chemical reactions that require energy are best termed _____.

Accepted Answer

A)  catabolic
B)  anabolic
C)  exergonic
D)  endergonic

Question 19

Chemically stable atoms are inert or less likely to form chemical bonds. A chemically stable element:

Accepted Answer

A)  has l full outer electron shell
B)  has the same number of protons as electrons
C)  has an atomic number is equal to the atomic mass
D)  forms hydrogen bonds

Question 20

Atoms are most likely to form ions when they have:

Accepted Answer

A)  an even number of electrons in their outer shells
B)  a nearly empty outer shell
C)  an odd number of electrons in their outer shells
D)  four electrons in their outer shells

Exam 2: Fundamentals of Chemistry

Proteins are chains of that sometimes function as__.