bio quiz 1/ exam one practice questions

With four distinct nucleotides, how many combinations are possible in a sequence of six nucleotides?

4,096

What percentage of carbon's orbitals are spherical in conformation?

40%

T or F: Earth's elemental composition is a good reflection of the elemental composition of the universe, especially in the relative amount of carbon present in each.

false

all autotrophs get their energy from sugar and fatty acids a. true b. false

false

glucose is stored in which of the following forms in human cells a. starch b. glycogen c. cellulose d. chitin

glycogen

how many more or less H+ is found in a solution at pH=^ than pH=4? a. 10x more b. 10x less c. 100x more d. 100x less

d. 1000x less

rank the following types of bonds from what you think are likely to be the strongest to the ones you think are the weakest in water solutions? 1. double bonds 2. hydrogen bonds 3. ionic bonds/ attractions 4. single covalent bonds 5. van der wall's forces a. 31425 b. 34125 c. 23451 d. 14325

d. 14325

which of the following is the best definition for a hydrogen bond a. an attraction between the nucleus of one atom and the electron of another b. the attractive force between oppositely charged hydrogen ions c. the equal sharing of electrons between atoms d. the attractive force between partially charged hydrogen atoms and electronegative atoms

d. the attractive force between partially charged hydrogen atoms and electronegative atoms

all hydrogen sharing electrons in covalent bonds can form hydrogen bonds a. true b. false

false

chemicals with larger bond strengths have more potential energy a. true b. false

false

electrons in the valence shell are __________ the atomic nucleus and have the ____________ energy farthest, most closest, least farthest, least closest, most

farthest from; most

As part of their normal function, many proteins bind to DNA briefly and then release it again. Which types of bonds might be involved in these transient protein-DNA interactions? a. hydrogenb. ionic c. covalent d. van der Waals forces e. all of the above f. a, b, and c g. a, b, and d

g. a, b, and d

________ are organisms or cells that use organic molecules as a source of carbon a. lithotroph b. autotroph c. chemotroph d. heterotroph

heterotroph

molecules with mainly C-H and C-C bonds are likely.... a. hydrophobic b. hydrophilic c. amphiphilic d. amphipathic

hydrophobic

micelles of amphipathic soap molecules for because: a. hydrophobic surfaces of the gap molecules attract each other in all water solutions b. hydrophilic surfaces of the soap molecules attract water molecules c. hydrophobic grouping increases the entropy of water d. hydrophobic interactions are stabilized by Van Der Waals force's

hydrophobic grouping increases the entropy of water

Where is the highest-energy electron found in an atom of hydrogen?

in the spherical orbital closest to the nucleus

why type of bond will occur between Se and H? a. hydrogen bond b. non polar covalent bond c. polar covalent bond d. ionic bond

non polar covalent bond

Two elements within the same group:

occupy the same column on the periodic table and have the same number of electrons in their outermost shell

Examination of meteorites has revealed that some molecules that would be considered precursors to early life could have formed in the early solar system. These are:

organic molecules, amino acids, and lipids

When chemical reactions occur the ___________ but the ________. pairing of atoms that share electron pairs changes; individual atomic nuclei stay the same number of protons and neutrons change; shared electrons stay the same number of shared electron pairs is unchanged; number of atomic nuclei changes

pairing of atoms that share electron pairs changes; individual atomic nuclei stay the same

which element has 5 electrons in its valance shell? a. phosphorus b. carbon c. oxygen d. hydrogen

phosphorus

Which one of the following elements is likely to form exactly three non-ionic interactions with hydrogen? a)carbon b)sulfur c)sulfur d)oxygen e)chlorine f)phosphorus g) nitrogen

phosphorus and nitrogen

oils are _______ with a high level of ________ fatty acids

triacylglyceroils: unsaturated

Van Der walls forces occur between every atom a. true, if they are the right distance apart b. false, water's kinetic nature ends up pushing hydrophobic molecules together c. false, hydrophobic molecules like water and interact freely with it d. false, only between carbon and hydrogen atoms

true, if they are the right distance apart

When H2CO3 reacts to form CO2 and H2O, what is the net change in the number of shared electron pairs? A., plus two B., minus two C., minus three D., zero

zero

which of the following molecules is hydrophobic? a. NaCl b. C2H4 c. (CH2O)n d. an amino acid

C2H4

which of the following molecules contain a polar covalent bond a. O2 B. CH2O C. N2 D. CH4

CH2O

Which of the following statements is true regarding atomic mass?

The atomic mass can be used to differentiate between different isotopes of the same element.

Water readily dissolves compounds that are referred to as

hydrophilic

the following amino acids R group would be classified as a a. hydrophobic R group b. hydrophilic R group c. Basic R group d. acidic R group

hydrophilic R group

why isn't life silicon based? a. silicon is not a very common element on earth b. because silicon has only 9 orbitals in its 3rd shell, its four valance electrons have limited movement and cannot form a wide variety of bonds c. silicon has such a high electronegativity that it is not a good electron acceptor d. silicon cannot form four bonds

because silicon has only 9 orbitals in its 3rd shell, its four valance electrons have limited movement and cannot form a wide variety of bonds

The molecule H2O has a dipole moment a. true b. false

true

Molecules made primarily of carbon and hydrogen are called hydrocarbons. How many hydrogen atoms are present in the following molecule? A hydrocarbon chain of five carbons joined to each other by single covalent bonds.

10

a solution of pH=2 has ________ H= atoms then a solution at pH=4 a. 100x more b. 2x more c. 10x less d. 2x less

100x more

Which of the following bonds rely on the attraction of positive and negative charges?A. Ionic bonds and covalent bonds B. Hydrogen bonds C. Ionic bonds D. Covalent bonds E. Ionic bonds and hydrogen bonds

Ionic bonds and hydrogen bonds

Which statement is correct regarding an atom with high electronegativity?

It will most likely be located near the right-most side of the periodic table of elements.

Humans are often referred to as carbon based life forms. Given that humans breathe oxygen, shouldn't humans be referred to as Oxygen based life forms?

No, because carbon is the most abundant element in human cells, not oxygen.

Which statement is true regarding the origin of nucleic acids on the early Earth?

Nucleic acids can assemble spontaneously, provided that there are an adequate number of available nucleotides.

A woman's doctor tells her to gargle with salt water. She stirs a tablespoon of salt into a cup of warm water, and watches it dissolve. Why does the salt dissolve in water?

The positive hydrogen atoms in water molecules are attracted to chlorine ions, and the negative oxygen atoms in water molecules are attracted to sodium ions.

hydrophilic molecules are attracted to water because a. they are charged molecules and water is a charged molecule so they are attracted b. they are uncharged molecules, and water is an uncharged molecule so they are attracted c. waters kinetic nature brings hydrophilic molecules together d. water has a strong magnetic force on hydrophilic molecules

a. they are charged molecules and water is a charged molecule so they are attracted

you have an aqueous solution with a pHof exactly 7.0. What would you add to make the solution more acidic? a. add a molecule with a number of amine groups or another weak base b. add deionized water (dH2O) c. add sodium hydroxide (NaOH) or another string base d. add a molecule with a carboxyl group or another type of acid

add a molecule with a carboxyl group or another type of acid

Which of the following was required for early life to form on Earth?low oxygen conditions, which allowed for the formation of amino acids*Clay, which allowed for the formation of nucleic acids*phosphates, which allowed for the formation of nucleotides*the presence of hydrogen, which allowed for the formation of amino acids*AOTA (all of the above)

all of the above

what kinds of interactions hold the tow DNA strands together in a double helix a. hydrophobic b. hydrogen c. van der waal's d. all of the above

all the above

A molecule of common table salt, or NaCl, is the result of _____ bond forming between a sodium (na) atom and a chlorine (Cl) atom.

an ionic

When chemical reactions occur the _________ but the ____________. atoms retain their identities; arrangement of bonds changes identity of atoms changes; arrangement of bonds is retained, number of bonds per atom changes; total number of bonds is retained

atoms retain their identities; arrangement of bonds changes

How many protons and neutrons are found in the neutral Mg atom a. 8 protons, 16 neutrons b. 12 protons, 12 neutrons c. 24 protons, 12 neutrons d. 24 protons, 24 protons

b. 12 protons, 12 neutrons

Which of the following elements shares the most similar properties with oxygen a. Ne b. S c. N d. C

b. C

Which choice ranks the elements hydrogen, carbon, nitrogen, and oxygen in order of decreasing dry mass in living organisms? C,h,o,n o,c,h,n n,c,o,h C,o,h,n

c, o, h, n

all of the following are polar covalent bonds except for ______ a. C-O b. C-N c. C-H d. N-H

c. C-H

hydrophobic molecules actively repel water molecules a. true b. false, war's kinetic nature ends up pushing hydrophobic molecules together c. false, hydrophobic molecules like water and interact freely with it d. false, hydrophobic molecules due to their neutral charge sit freely in water

c. false, hydrophobic molecules like water and interact freely with it

Stanley miller's 1953 experiments absolutely proves that______ a. all life on earth arose from simple organic molecules, with energy from lightning and volcanoes b. the conditions on early earth were conducive to the synthesis of organic molecules c. organic molecules can by synthesized under particular conditions d. all life on earth arose from simple inorganic molecules

c. organic molecules can by synthesized under particular conditions

If hydrogen bonds between water molecules were weaker than they are today, how would this affect plant height?

As hydrogen bonds are responsible for the movement of water through plant vasculature, plants would be shorter.

which of the following is the complementary strand of DNA associated with the strand below? 5'ATCACGTA3' a. 5'TAGTGCAR3' B. 3'TAGTGCAT5' C. 5'ATCACGTA3' D. 3'ATCACGTA5'

B. 3'TAGTGCAT5'

Many cellular processes represent work that requires the expenditure of energy. Which of the actions is not a cellular process that requires the cell to expend energy? Contraction of muscle cells. Diffusion of water into cells. Synthesis of large biomolecules like proteins and nucleic acids. Keeping sodium ion concentration lower inside a cell than outside the cell.

Diffusion of water into cells.

Evidence exists that atmospheric CO2 has increased over the last several decades due to human activities. How does increased CO2 levels affect the pH of Earth's waters?

Due to the formation of carbonic acid, increased CO2 levels decrease the pH of Earth's waters.

Using the periodic table provided, select the element that would be found in least abundance in a living cell. A) hydrogen (H) B) sodium (Na) C) phosphorous (P )D) zinc (Zn) E) silicon (Si)

E) silicon

Which of the factors accounts for the higher potential energy of C-C and C-H bonds compared to C-O and H-O bonds? The C-C and C-H bonds are weak, thus requiring a lot of energy to hold together. The C-O and H-O bonds are weak, thus requiring less energy to hold together. The C-O and H-O bonds are strong, thus requiring a lot of energy to hold together. The C-C and C-H bonds are strong, thus requiring a lot of energy to hold together.

The C-C and C-H bonds are weak, thus requiring a lot of energy to hold together.

what is the chemical basis for water's role as the universal solvent? because water is polar, it disrupts most covalent bonds because water is polar, it disrupts both hydrogen and ionic bonds because water is polar, it disrupts hydrogen bonds because water is polar it disrupts both covalent and hydrogen bonds

because water is polar, it disrupts both hydrogen and ionic bonds.

Some species of insects are able to walk across liquid water because: a. higher density of liquid water compared to solid water. b. capacity of water to function as a solvent. c. high specific heat of water. d. low gravitational effect of their body weight relative to the amount of water. e. high surface tension of water due to its cohesion.

e. high surface tension of water due to its cohesion

Hydrogen bonding is ultimately due to differences in _____ between two atoms.

electronegativity

in general, colder temperatures reduce the fluidity of the membrane, so cells will produce different types of phospholipids of maintain the proper degree of fluidity. how would the membrane change in response to colder temperatures a. the amount of unsaturated fatty acids would increase b. the amount of unsaturated fatty acids would decrease c. the amount of saturated fatty acids would increase d. the length of the fatty acids would be longer

the amount of unsaturated fatty acids would increase

what is the difference between the N14 isoform (atomic mass= 14) of nitrogen and the N15 isoform (atomic mass= 15) of nitrogen? a. the number of neutrons b. the number of protons c. the number of electrons d. the position of the electron orbitals

the number of neutrons