Biology Exam #1 Final
How many electrons are involved in a double covalent bond?
Four
A new organism is discovered in the forests of Costa Rica. Scientists there determine that the polypeptide sequence of hemoglobin from the new organism has 72 amino acid differences from humans, 65 differences from a gibbon, 49 differences from a rat, and 5 differences from a frog. These data suggest that the new organism is more closely related to _____.
Frogs than to humans
One of the primary functions of RNA molecules is to _____.
Function in the synthesis of proteins
Which of the following solutions would require the addition of the greatest amount of base to bring the solution to a neutral pH?
Gastric juice at pH 2
Which of the following in NOT a polymer?
Glucose
Which of the following are compounds?
H2O and CH4, but not O2
Which of the following statements is FALSE? Saturated fats _____.
Have many double bonds in the carbon chains of their fatty acids
What element does not prefer to react with other elements?
Helium
Water molecules are attracted to one another by _____.
Hydrogen bonds
Which type of bond must be broken for water to vaporize?
Hydrogen bonds
Use the following information when answering the corresponding question(s).
In 1668, Francesco Redi performed a series of experiments on spontaneous generation. He began by putting similar pieces of meat into eight identical jars. Four jars were left open to the air, and four were sealed. He then did the same experiment with the variation: Instead of sealing four of the jars completely, he covered them with gauze (the gauze excluded the flies while allowing the meat to be exposed to air). In both experiments, he monitored the jars and recorded whether or not maggots (young flies) appeared in the meat.
If an atom has a charge of +1, which of the following must be true?
It has one more proton than it does electrons
Which of the are qualities of any good scientific hypothesis?
It is testable & It is falsifiable
Which of the following is (are) true of natural selection?
It requires genetic variation, results in decent with modification, and involves differential reproductive success.
Recall the caterpillar experiment in which caterpillars born in the spring looked like flowers, and caterpillars born in the summer looked like twigs. What is the most likely selective advantage for this difference in body shape?
Looking like their food source lets the caterpillars blend into their surroundings, reducing predation.
Refer to the paragraph on Redi's experiments. What hypothesis was being tested in the initial experiment with open versus sealed jars?
Maggots do not arise spontaneously, but from eggs laid by adult flies.
A molecule with the chemical formula C6H12O6 is probably a _____.
Monosaccharide
Which pair of elements would likely have similar valency and thus similar chemical behavior?
Nitrogen & phosphorus
Bonds between two atoms that are equally electronegative are _____.
Nonpolar covalent bonds
The relation between amino acid and polypeptide is similar to the relation between _____.
Nucleotide and nucleic acid
Nucleic acids are polymers made up of which of the following monomers?
Nucleotides
A covalent bond is likely to be polar when _____.
One of the atoms sharing electrons is more electronegative than the other atom.
Stanley Miller's 1953 experiments supported the hypothesis that _____.
Organic molecules can be synthesized abiotically under conditions that may have existed on early Earth.
A covalent chemical bond is one in which _____.
Outer-shell electrons of two atoms are shared so as to satisfactorily fill their respective orbitals.
In living systems molecules involved in hydrogen bonding almost always contain either oxygen or nitrogen or both. How do you explain this phenomenon?
Oxygen and nitrogen are elements with very high attractions for their electrons
In a single molecule of water, two hydrogen atoms are bonded to a single oxygen atom by _____.
Polar covalent bonds
A localized group of organisms that belong to the same species is called a _____.
Population
Based on your knowledge of the polarity of water molecules, the solute molecule depicted here is most likely _____.
Positively charged
Which level of protein structure do the α-helix and the β-pleated sheet represent?
Secondary
When Stanley Miller applied heat and electrical sparks to a mixture of simple inorganic compounds such as methane, hydrogen gas, ammonia, and water vapor, what compounds were produced?
Simple organic compounds, amino acids, & hydrocarbons
Water has many exceptional/useful properties. Which is the rarest property among compounds?
Solid water is less dense than liquid water
The molecule shown in the figure is a _____.
Steroid
The figure above shows the structures of glucose and fructose. These two molecules are _____.
Structural isomers
The two molecules shown in the figure below are best described as _____.
Structural isomers
The application of scientific knowledge for some specific purpose is known as _____.
Technology
The following experiment is used for the corresponding question(s). A researcher discovered a species of moth that lays its eggs on oak trees. Eggs are laid at two distinct times of the year: early in spring when the oak trees are flowering and in midsummer when flowering is past. Caterpillars from eggs that hatch in spring feed on oak flowers and look like oak flowers. But caterpillars that hatch in summer feed on oak leaves and look like oak twigs. How does the same population of moths produce such different-looking caterpillars on the same trees? To answer this question, the biologist caught many female moths from the same population and collected their eggs. He put at least one egg from each female into eight identical cups. The eggs hatched, and at least two larvae from each female were maintained in one of the four temperature and light conditions listed below. In each of the four environments, one of the caterpillars was fed oak flowers, the other oak leaves. Thus, there were a total of eight treatment groups (4 environments X 2 diets).
Temperature---------Day Length Springlike------------Springlike Springlike------------Summerlike Summerlike----------Springlike Summerlike----------Summerlike
What is the major structural difference between starch and glycogen?
The amount of branching that occurs in the molecule
The complexity and variety of organic molecules is due to _____.
The chemical versatility of carbon atoms
What component of amino acid structure varies among different amino acids?
The components of the R group
Refer to the accompanying figure. Recall that eggs from the same female were exposed to each of the eight treatments used. This aspect of the experimental design tested which of the following hypotheses?
The differences are genetic. A female will either produce all flower-like caterpillars or all twig-like caterpillars.
Refer to the paragraph on Redi's experiments. In both experiments, flies appeared in all of the open jars and only in the open jars. Which one of the following statements is correct?
The experiment supports the hypothesis that maggots arise only from eggs laid by adult flies.
Knowing the atomic mass of an element allows inferences about which of the following?
The number of protons plus neutrons in the element.
Which statement correctly identifies the result that the optimum pH for amylase function is 7?
The pH with the highest absorbance values would indicate the optimum pH for amylase since this pH does not affect the structure or function of the protein.
The unique chemical qualities of individual amino acids do not directly determine the function of an enzyme. What, then, is the role of the individual amino acid's unique chemical qualities, and what directly determines the function of an enzyme?
The peptide bonds determines the function of the enzyme. The role of the individual amino acid is to determine what bonds happen for which protein is needed the most.
How do phospholipids interact with water molecules?
The polar heads interact with water; the nonpolar tails do not
How does a scientific theory differ from a scientific hypothesis?
Theories are usually an explanation for a more general phenomenon, hypotheses typically address more specific issues
Which of the following statements is true about buffer solutions?
They maintain a relatively constant pH when either acids or bases are added to them
How many electrons are involved in a single covalent bond?
Two
Which of the following is a major difference between RNA and DNA?
Type of sugar
The tertiary structure of a protein is the _____.
Unique three-dimensional shape of the fully folded polypeptide
When are atoms most stable?
When all of the electron orbitals in the valence shell are filled
The molecule illustrated in the figure _____.
Will be liquid at room temperature
Can the atomic mass of an element vary?
Yes. Adding or losing neutrons will change the atomic mass without forming a different element.
You find yourself standing next to a beautiful rose bush. Which of the following do you and the rose have in common?
You both are multicellular
A controlled experiment _____.
includes at least two groups, one of which does not receive the experimental treatment
Which of the following combinations of molecules illustrated could be linked to form a nucleotide?
11, 12, and 13
In carbohydrates, the ratio of hydrogen (H) to oxygen (O) is _____.
2:1
How many electron pairs does carbon share in order to complete its valence shell?
4
Which molecule has hydrophilic and hydrophobic properties and found in plasma membranes?
5
Which molecule is a saturated fatty acid?
8
When nucleotides polymerize to form a nucleic acid _____.
A covalent bond forms between the sugar of one nucleotide and the phosphate of a second
The partial negative charge at one end of a water molecule is attracted to the partial positive charge of another water molecule. What is this attraction called?
A hydrogen bond
In the process of science, which of these is tested?
A hypothesis
Which of the following can be attributed to water's high specific heat?
A lake heats up more slowly than the air around it
Which of the following descriptions best fits the class of molecules known as nucleotides?
A nitrogenous base, a phosphate group, and a sugar
What results from an unequal sharing of electrons between atoms?
A polar covalent bond.
Which of the following effects can occur because of the high surface tension of water?
A raft spider can walk across the surface of a small pond
Identical heat lamps are arranged to shine on two identical containers, one containing water and one methanol (wood alcohol), so that each liquid absorbs the same amount of energy minute by minute. The covalent bonds of methanol molecules are nonpolar, so there are no hydrogen bonds among methanol molecules. Which of the following graphs correctly describes what will happen to the temperature of the water and the methanol?
A. Methanol temperature increases faster than water
Which of the following molecules is a part of ATP?
Adenosine
In sickle-cell disease, as a result of a single amino acid change, the mutant hemoglobin tetramers associate with each other and assemble into large fibers. Based on this information alone, we can conclude that sickle-cell hemoglobin exhibits _____.
Altered primary structure and altered quaternary structure, the secondary and tertiary structures may or may not be altered
Misfolding of polypeptides is a serious problem in cells. Which of the following diseases are associated with an accumulation of misfolded polypeptides?
Alzheimer's & Parkinson's
If you change the number of neutrons in an atom, you create _____.
An isotope
Lipids _____.
Are insoluble in water.
Thalidomide and L-dopa, shown below, are examples of pharmaceutical drugs that occur as enantiomers, or molecules that _____.
Are mirror images of one another
Steroids are considered to be lipids because they _____.
Are not soluble in water
Starch and cellulose _____.
Are polymers of glucose
In comparison to to eukaryotes, prokaryotes _____.
Are smaller
The figure above shows the structures of glucose and fructose. These two molecules differ in the _____.
Arrangement of carbon, hydrogen, and oxygen atoms
Which of the structures illustrated above is an impossible covalently bonded molecule?
B.
Prokaryotes are classified as belonging to two different domains. What are the domains?
Bacteria and Archaea
Why does sweating cool your skin on a hot, dry day but make you feel warmer on a hot, humid day?
Because of water's specific heat property. Water retains heat so on a humid day the water in the air around you will be warmer while on a cooler day the air around you will be cooler.
The molecular formula for glucose is C6H12O6. What would be the molecular formula for a molecule made by linking three glucose molecules together by dehydration reactions?
C18H32O16
The element present in all organic molecules is _____.
Carbon
About twenty-five of the ninety-two natural elements are known to be essential to life. Which four of these twenty-five elements make up approximately 96 percent of living matter?
Carbon, hydrogen, nitrogen & oxygen
Which two functional groups are always found in amino acids?
Carboxyl and amino groups
What does the term insoluble fiber refer to on food packages?
Cellulose
The two molecules shown in the figure are best described as _____.
Cis-trans isomers
Saturated fats _____.
Contain more hydrogen than unsaturated fats that consist of the same number of carbon atoms
A carbon atom is most ;likely to form what kind of bond(s) with other atoms?
Covalent
What is the difference between covalent bonds and ionic bonds?
Covalent bonds involve the sharing of electrons between atoms; ionic bonds involve the electrical attraction between charged atoms
The central role of molecular biology states that _____.
DNA is transcribed into RNA, which is translated into protein
Which of the following best summarizes the relationship between dehydration reactions and hydrolysis?
Dehydration reactions assemble polymers, hydrolysis reactions break polymers apart
Which of the following is the strongest evidence that protein structure and function are correlated?
Denatured (unfolded) proteins do not function normally.
Refer to the accompanying figure. Which one of the following is NOT a plausible hypothesis to explain the differences in caterpillar appearance observed in this population?
Differences in air pressure, due to differences in elevation, trigger the development of different types of caterpillars
Refer to the accompanying figure. In every case, caterpillars that feed on oak flowers look like oak flowers. In every case, caterpillars that were raised on oak leaves looked like twigs. These results support which of the following hypotheses?
Differences in diet trigger the development of different types of caterpillars.
In what way are elements in the same column of the periodic table the same? They have the same number of _____.
Electrons in their valence shells when neutral
