Deck 2: The Chemistry of Life

Question 1

The observations and research on aphid color changes can most directly be summarized in that

A) Koga and Fugatsu proved that the color change from red to green in aphids was ecologically favorable to survival.
B) species of organisms can be chemically diverse and affect each other, even among similar groups of aphids and bacteria.
C) the method of paper fiber separation of pigment molecules showed that Ricketsiella bacteria were the source of the green coloration of aphids.
D) it turned out that the green appearance of aphids was because of the large amount of green Ricketsiella bacteria coating their bodies.

Answer 1

B

Question 2

The initial experiment of Koga and Fugatsu,in testing for any bacterial cause of aphid color change,involved all of these except

A) the specific amounts of red and green pigment molecules were initially measured as dependent variables.
B) a group of aphids infected with Rickettsiella bacteria was grown, then killed in order to produce an extract to test on red aphids.
C) a group of green aphids was grown, then killed in order to produce an extract to test on red aphids.
D) a group of red aphids was grown as a control group.
E) a group of red aphids was treated with the independent variable of Rickettsiella bacteria infection from green aphids.

Answer 2

A

Question 3

The ring structure of glucose indicates that it is a(an)

A) disaccharide.
B) fatty acid.
C) monosaccharide.
D) nucleotide.
E) amino acid.

Answer 3

C

Question 4

In the 1700s,a French scientist,Antoine Lavoisier gained new experimental information about how chemistry works.He isolated chemicals that were reacting,including a metal and an acid.His observation of the results seemed to show that much of the metal had been lost in the chemical reaction.Yet,upon weighing the system,the total amounts of materials had not changed during the reaction.His resulting law of Conservation of Mass also applies to biology,because the materials we are made of are _________ that change forms,but aren't truly lost as we conduct life chemical reactions.

A) isotopes
B) energy
C) solutions
D) matter

Question 5

The diagram shows glucose and fructose before the chemical reaction called ______ builds a larger polymer from the two monomers.

A) evaporation
B) dehydration synthesis
C) hydrolysis
D) reproduction

Question 6

The unique properties of water,including its strength as a solvent,its three environmental stages of solid,liquid,and gas,and its temperature regulation,are a result of

A) symmetric balance of electronegativity as shared electrons orbit equally around the hydrogens and oxygens.
B) the cohesion and adhesion of water molecules that bond more strongly to each other than other substances.
C) unbalanced electronegativity of the hydrogens and oxygens as they share electrons.
D) the imbalance in numbers of electrons around hydrogen and oxygen valence shells after they ionically bond.

Question 7

Figuer:
Examine this image of the glucose molecule.
This glucose molecule is a(an)

A) triglyceride.
B) disaccharide.
C) polymer.
D) carbohydrate.

Question 8

Figuer:
Examine these two sugars, as shown prior to the chemical reaction that would bond them.
These glucose and fructose molecules will bond to form a monosaccharide with the removal of water.

Question 9

Researchers noted that only few aphids changed color to green from their original red.This is an unusual observation among any animals.What research question came out of the observations?

A) Will green aphids change their color to red, or remain green as they age?
B) Is the color shift of certain aphids due to genetics or some other factor?
C) The color shift of certain aphids is due to genetics within the species.
D) Do other aphids change colors as they age?

Question 10

Figuer:
Examine this image of the glucose molecule.
In our diets,this molecule is often covalently bonded with others in the polymer form of

A) a complex carbohydrate.
B) a fatty acid chain.
C) a triglyceride.
D) a simple sugar.

Question 11

The atomic number of an element is the number of

A) protons in the orbitals.
B) neutrons in the orbitals.
C) neutrons in the nucleus.
D) protons in the nucleus.
E) electrons in the nucleus.

Question 12

Compared with a molecule of glucose,this starch molecule does NOT have which characteristic below?

A) This molecule is used by cells for long-term storage and release of energy for cell functions.
B) This molecule is used by cells for quick release of energy for cell functions.
C) This molecule can provide structure for cells that contain it.
D) This molecule is a complex carbohydrate polymer.

Question 13

Figuer:
Refer to this diagram with common examples of substances and their pH.
Our normal blood pH should be in a fairly narrow range.Imagine you sit down to eat a large meal with cola,tomato-based sauce,and a salad with many citrus fruit slices.Identify the one statement that does not apply as one of the likely outcomes of your meal.

A) The cola, tomato and citrus fruits will add hydrogen (H⁺) to your blood and body fluids.
B) Your blood and body fluids will likely become more basic, with higher pH than the normal range.
C) Your body will produce buffer molecules to help neutralize acids you ate, so your blood pH doesn't change much.
D) Your blood and body fluids will likely become more acidic, with lower pH than the normal range.

Question 14

What is the link between colored pigment molecules and other organic molecules?

A) The DNA molecule genetic sequence regulates protein molecule function, which can specifically modify pigment structure that affects color.
B) In the case of the aphids, the pigment molecules of bacteria are genetically passed on to the DNA of infected aphids.
C) This one group of aphids can easily alter the pigment molecule structure by modifying its DNA nucleotide sequence and building new proteins.
D) Pigment molecules are complex, made up of all four of the other organic molecule groups.

Question 15

A conscientious person habitually reads nutrition labels on food packages for weight watching and general health.The main nutritional molecules are made up of

A) buffers.
B) trace elements.
C) isotopes.
D) bulk elements.

Question 16

The primary elements making up living organisms are

A) carbon, hydrogen, oxygen, sulfur, nitrogen, and phosphorus.
B) carbon, hydrogen, iron, sulfur, sodium, and calcium.
C) carbon, oxygen, iron, chlorine, sulfur, and phosphorus.
D) carbon, hydrogen, oxygen, calcium, iron, and iodine.
E) carbon, oxygen, sulfur, calcium, iron, and phosphorus.

Question 17

Figuer:
Refer to this diagram with common examples of substances and their pH.
The correct functions of your lungs contribute to the normal pH level of between 7.35 and 7.45.If your lungs do not exchange and remove carbon dioxide from your blood,the blood pH will change.A pH 6.4 reading of your blood indicates

A) a health problem due to the pH value being 10X higher H⁺ concentrations than normal in your body.
B) a health problem due to the pH value being 10X higher OH^- concentrations than normal in your body.
C) a health problem due to the pH value being 2X higher OH^- concentrations than normal in your body.
D) no health risk, as part of normal pH changes in your body that in this case bring it closer to neutral pH.
E) a health problem due to the pH value being 2X higher H⁺ concentrations than normal in your body.

Question 18

An ion is an atom that has

A) a net negative or positive charge, with number of electrons different from number of protons.
B) a net positive charge.
C) the same number of electrons as it does protons.
D) a net negative charge.
E) a different number of neutrons from the number of protons.

Question 19

The mass number is defined as the total number of __________ of an atom.

A) neutrons and electrons
B) protons
C) protons, neutrons, and electrons
D) protons and neutrons
E) protons and electrons

Question 20

Given this information from one element in the periodic table of elements,the number of neutrons and protons is

A) 7, which is the atomic number indicated.
B) 7, which is the atomic mass indicated.
C) 14, which is the atomic number indicated.
D) not discernable, because the number of electrons is also needed.
E) 14, which is the atomic mass indicated.

Question 21

The first energy shell of an atom contains a maximum of ________ electron(s).

A) one
B) two
C) eight
D) four
E) sixteen

Question 22

In a chemical equation,which components of a chemical reaction is not noted in symbols and abbreviations?

A) Some substance atoms on the left side of the chemical reaction arrow must be destroyed in order to form the substances on the right side.
B) The reactants, or starting substances, are on the left of the chemical reaction arrow.
C) The products, or ending substances, are on the right of the chemical reaction arrow.
D) Reactants and products are on both sides of the yields arrow.
E) The number of atoms of each element must be the same, balanced on each side of the chemical reaction arrow.

Question 23

An acid

A) has a value above seven on the pH scale.
B) is a chemical that takes hydrogen ions from a solution.
C) has a value of seven on the pH scale.
D) is a chemical that adds hydrogen ions to a solution.
E) All of the answer choices are correct.

Question 24

You collect and measure samples of ice and surrounding ice water from a stream in the Winter.You find that you collected the same number of water molecules in each form.Water in the ice (solid)form floats in water of the liquid form because

A) in the ice form, the same number of water molecules are found in a crystal form, yet total larger volume than the liquid water.
B) in the ice form, the same number of water molecules are found in a solid, more compact volume than the liquid water.
C) once the water molecules froze into ice, they became hydrophobic, and started repelling from the liquid.
D) the ice is actively melting, since it was surrounded by the liquid water in the stream where it was collected.

Question 25

Within a single molecule of water,as shown,____ bonds are formed between oxygen and hydrogen.

A) hydrophobic
B) hydrogen
C) nuclear
D) ionic
E) covalent

Question 26

An element is found to have atoms with eight electrons in its valence shell.The atoms will be ____

A) highly reactive.
B) not chemically stable.
C) chemically stable.
D) highly likely to combine with other atoms.
E) not inert.

Question 27

Trees are able to transport water from the roots to the top branches because

A) cohesion bonds water molecules to each other strongly.
B) adhesion bonds water molecules to the insides of the plant cells.
C) liquid water has a higher density than the air in the plant cells of the roots, trunk and branches.
D) water acts as a solvent of the tree cells as it moves upwards to the branches.

Question 28

The property of water demonstrated by this water strider,as it remains on top of the water,is that water is a universal solvent.

Question 29

Carbon and hydrogen make up many biologically important molecules.Carbon has an electronegativity of 2.55 while hydrogen has an electronegativity of 2.0.On the scale of electronegativity from zero (0)to four (4),the carbon and hydrogens shown here have just formed

A) a nonpolar covalent bond.
B) a hydrogen bond.
C) a polar covalent bond.
D) an ionic bond.

Question 30

Algal phytoplankton are single-celled water organisms that can do photosynthesis like plants.In a lake,summer growth of phytoplankton can change the water pH from pH 7.2 to 6.2.This change indicates all of these except

A) the water at pH 6.2 is a stronger acid solution than before the phytoplankton growth.
B) the water at pH 6.2 has ten times the hydrogen (H⁺) concentration as before the phytoplankton growth.
C) the water at pH 6.2 has twice the hydrogen (H⁺) concentration as before the phytoplankton growth.
D) the lake water solution changed from slightly basic to slightly acidic in pH.

Question 31

In the example of ionic bond formation between sodium and chlorine,as shown,which of the following is not a true statement?

A) Sodium donates an electron.
B) The bond that is formed is stronger than a hydrogen bond.
C) Na is the chemical symbol for sodium.
D) Sodium becomes positively charged.
E) Chlorine donates an electron.

Question 32

In a covalent bond,atoms

A) share a proton.
B) share electrons.
C) of opposite charges attract each other.
D) both become highly electronegative.

Question 33

You can painlessly wade into a pool,but doing a belly flop off of the high diving board hurts because of

A) water's neutral pH.
B) adhesion in water.
C) cohesion in water.
D) water's high density.
E) water's high boiling point.

Question 34

A base

A) is a chemical that absorbs hydrogen ions from a solution.
B) has a value of 7 on the pH scale.
C) has a value below 7 on the pH scale.
D) is a chemical that adds hydrogen ions to a solution.

Question 35

Organic molecules are defined as chemical compounds that chiefly contain ______ in fairly distinct ratios and structures.

A) carbon and oxygen
B) carbon and nitrogen
C) carbon
D) carbon, hydrogen, and nitrogen
E) carbon and hydrogen

Question 36

Evaporation of water is

A) a phase change of water from liquid into a vapor.
B) a phase change of water from solid into a vapor.
C) a phase change of water from vapor into a liquid.
D) a phase change of water from vapor into a solid.
E) All of the answer choices are correct.

Question 37

The chapter concept map links covalent and ionic bonds as chemical bonds that attract atoms or molecules.What is the chemical bond characteristic that contributes to the numerous important properties of water molecules for living organisms?

A) The covalent bond strengths of water molecules change with pH, temperature, or solute conditions present.
B) The covalent bonds that form water molecules transform to ionic bonds in presence of other molecules, temperature changes, or pH.
C) Hydrogen bonds form between water molecules, not requiring gain, loss, or sharing of electrons.
D) Bonds that form water are of the nonpolar covalent form.

Question 38

Which statement summarizes the distinction between nonpolar and polar covalent bonds?

A) The electrons are more evenly and symmetrically distributed in orbit among atoms in a nonpolar covalent bond.
B) Polar covalent bonds are formed when the atoms gain or lose electrons to bond, and become oppositely charged ions.
C) The difference in electronegativity of the atoms in a nonpolar covalent bond is very large.
D) The electrons are more evenly and symmetrically distributed in orbit among atoms in a polar covalent bond.

Question 39

If a molecule is added to a glass of water,and is easily dissolved by the water,the added molecule is described as hydrophilic.

Question 40

In an ionic bond,

A) two atoms both become strongly electronegative and attract each other.
B) atoms attract each other by sharing electrons to fill their valence shells.
C) atoms, having gained or lost electrons, attract one another with opposite charges.
D) two atoms are attracted by partial positive and negative charges.

Question 41

Saturated fats have long straight tails of fatty acids,and can pack or clump tightly together in cells and animal bodies.Unsaturated fats have kinks in their tails due to double bonds,which prevents them from packing together as tightly.Animals that are ectothermic (their body temperature fluctuates with the environment)need to keep their membranes fluid at cooler temperature and thus use ______ in their membranes.

A) mostly unsaturated fats
B) mostly saturated fats
C) equal amounts of saturated and unsaturated fats
D) carbohydrates
E) proteins

Question 42

Examples of monosaccharides are

A) glucose, maltose, and cellulose.
B) glucose, lactose, and maltose.
C) glucose, ribose, and fructose.
D) glucose, lactose, and cellulose.
E) None of these answers are correct; all options list lipids.

Question 43

____ bonds are formed between monomers to form a polymer.

A) Hydrogen
B) Covalent
C) Nuclear
D) Hydrophobic
E) Ionic

Question 44

The comparison listed below that is not true in distinguishing DNA from RNA is that

A) DNA has a main function of storing our genetic code, while RNA is used in units to build specific proteins in a cell.
B) DNA is a long two-sided molecule while RNA is a shorter single-sided molecule.
C) DNA and RNA share all nucleotides, except that RNA has Uracil instead of Thymine.
D) DNA is a molecule that stores and regulates our genetics, while RNA is used for cellular energy storage and release for biological functions.

Question 45

The primary building block (monomer)of nucleic acids is

A) a glucose molecule.
B) a fatty acid.
C) a nucleotide.
D) an amino acid.
E) a group of four interconnected rings.

Question 46

Many diseases,cancers and even normal human variations can be caused by mutations and variations in the DNA nucleotide sequence.The most likely immediate result of DNA having a different nucleotide sequence is that

A) the peptide bonds in the protein would by hydrolyzed and the protein would fall apart.
B) the protein resulting from the DNA mutation would be denatured and nonfunctional.
C) the primary structure of R group sequence in a protein would be altered.
D) no direct result of change in the protein molecule would occur if DNA is mutated.

Question 47

Cohesion is a property of water in which water molecules tend to stick together.

Question 48

A peptide bond is a covalent bond formed between the amino group of one amino acid and the R group of another amino acid.

Question 49

An amino acid contains a structural "backbone" chain of

A) nitrogens and carbons.
B) phosphorus atoms.
C) carbons.
D) nitrogens.
E) carbon and phosphorus atoms.

Question 50

The primary building block (monomer)of proteins is

A) a nucleotide.
B) a fatty acid.
C) a glucose molecule.
D) a group of four interconnected rings.
E) an amino acid.

Question 51

The four nitrogen bases found in RNA are

A) adenine, thymine, guanine, and uracil.
B) adenine, cytosine, guanine, and uracil.
C) adenine, thymine, cytosine, and uracil.
D) thymine, cytosine, guanine, and uracil.
E) None of the answer choices are correct.

Question 52

The group of organic molecule polymers with the most complex and diverse three-dimensional structure are

A) unsaturated fats.
B) proteins.
C) carbohydrates.
D) waxes.
E) saturated fats.

Question 53

The three major components in a nucleotide are

A) a nitrogen base, a five-carbon sugar, and a phosphate group.
B) a carboxyl group, an R group, and an amino group.
C) glucose, a nitrogen base, and a phosphate group.
D) a nitrogen base, a six-carbon sugar, and a phosphate group.
E) glucose, a fatty acid, and glycerol.

Question 54

Sugars (CH₂O)_n dissolve well in water because sugars form ____ bonds with water.

A) hydrophobic
B) hydrogen
C) non-polar
D) ionic
E) covalent

Question 55

Saturated fats have long straight tails of fatty acids,while unsaturated fats from vegetables have kinks in their tails due to double bonds.These kinks prevent the fats from packing together as tightly.Hydrogenated vegetable oils,or trans fats,have hydrogens added back to the double bonds and thus behave like

A) carbohydrates.
B) waxes.
C) unsaturated fats.
D) saturated fats.
E) proteins.

Question 56

The four major groups of organic compounds are

A) carbohydrates, lipids, steroids, and monosaccharides.
B) lipids, fats, waxes, and steroids.
C) carbohydrates, proteins, amino acids, and nucleic acids.
D) carbohydrates, lipids, proteins, and nucleic acids.
E) fats, waxes, carbohydrates, and amino acids.

Question 57

The bond that builds amino acid monomers into protein polymers is

A) a denatured hydrogen bond.
B) an ionic bond also known as a peptide bond.
C) a covalent bond also known as a peptide bond.
D) a primary structural bond.

Question 58

Blood pH is closely maintained at a pH of 7.4.A patient whose blood pH drops below 7.35 is suffering from metabolic acidosis and can go into a coma.What happens to the concentration of H⁺ ions in a patient with a blood pH of 6.4?

A) H⁺ concentration is increased 2-fold.
B) H⁺ concentration is decreased 2-fold.
C) H⁺ concentration is increased 10-fold.
D) H⁺ concentration is decreased 4-fold.
E) H⁺ concentration is decreased 10-fold.

Question 59

In living cells,a process by which cells break polymers down into monomers by breaking covalent bonds is

A) hydrolysis.
B) dehydration synthesis.
C) reproduction.
D) All of the answer choices are correct.

Question 60

Which is not a lipid?

A) a triglyceride
B) a phospholipid
C) a wax
D) a sterol
E) a starch

Question 61

Among numerous functions of common proteins,which of these pairs does not correctly match a protein with its function?

A) DNA polymerase helps synthesize new DNA before our cells divide.
B) Antibodies regulate sweat to keep infections out of our skin pores.
C) Collagen is a structural protein to support hair, skin, and nails.
D) Insulin regulates blood glucose levels.
E) Hemoglobin protein transports oxygen to our cells.

Question 62

Having the typical ratio of carbon,hydrogen,and oxygen of carbohydrates,the chemical formula for glucose is

A) C₁₂H₂₂O_11.
B) C₆H₆O_12.
C) C₆H₁₂O_6.
D) C₁₂H₆O_12.
E) C₆H₆O_6.

Question 63

Our general economic source of unsaturated fatty acids is from plants,and composed of at least one pair of double-bonded carbons.

Question 64

A substance in which other substances dissolve is called a solute.

Question 65

Of the 20 common amino acids in all organisms,essential amino acids are those we must consume in food.

Question 66

Proteins store the genetic information of the cell and transmit it to the next generation.

Question 67

If a carbohydrate polymer is limited to two monomer units,such as sucrose made from glucose and fructose,it is called

A) an oligosaccharide.
B) a disaccharide.
C) a polysaccharide.
D) a monosaccharide.

Question 68

If a protein is denatured,its structure has been changed enough to make the protein nonfunctional.