91 terms

BIO 111 QUIZ 1

CHAPTER 2, 3, 4
A carbonated soft drink that has a pH of 3 is ________ times more acidic than water.
The second orbital shell of an atom can hold ____ electrons.
Urine, with a pH of 6, is _________ times more acidic than seawater, with a pH of 8.
atomic number for nitrogen
what is carbo loading
It is a method by which athletes can increase the usual amount of glycogen that is stored in their muscles and liver, increasing the amount of fuel available for extended exertion and delaying the onset of fatigue during an endurance event.
Why do coastal areas have milder, less variable climates than inland areas?
Large bodies of water, especially oceans, can absorb huge amounts of heat from the sun during warm times of the year, reducing temperature increases on the land. Similarly, during cold times of year the ocean slowly cools, giving off heat that reduces the temperature drop on shore.
polysacchrides are always
Both a) and c) are correct.
Which type of macromolecule is an informational molecule?
An enzyme that can bind to and break apart molecules of lactose should also be able to bind:
None of the above is true; this enzyme could bind none of these.
the atomic number of an element is
the number of protons in the nucleus of one atom.
An atom can be changed into an ion by adding or removing:
an electron
When you put a piece of chocolate on your tongue, your brain registers a sensation of sweetness. What aspect of molecules is responsible for their having a particular taste?
the molecules shape
A complex polymer built of monosaccharides is called a
a polysacchride
Just four elements make up more than 96% of the human body. These include:
carbon, oxygen, hydrogen, and nitrogen.
enzymes are composed of
amino acids
An electrically balanced atom of chlorine (Cl) has 17 protons in its nucleus. How many electrons does it have in its outermost shell?
The nucleus of an atom is usually made up of:
protons that have a positive charge and neutrons that have no electrical charge
multiple atoms linked together are called:
a molecule
The four most abundant elements in living organisms are:
hydrogen, nitrogen, oxygen, and carbon.
Energy used in cellular respiration can originate from:
carbohydrates, proteins, and fats.
evaporation from the leaves of a tree will pull water up through the roots as an unbroken column throughout the entire height of the tree. This feat is possible because of which characteristic(s) of water?
Pure water and aqueous solutions that are neither acidic nor basic are said to be:
Which of the following properties is a result of hydrogen bonding between water molecules?
All of the above are true.
The pH scale is a direct measure of:
the concentration of hydrogen ions in a solution.
In an uncharged atom, the number of protons and ___________ must be equal.
A complex polymer built of amino acids is called a(n):
One consequence of protein denaturation is:
the protein loses its functionality.
Male gypsy moths are attracted by airborne chemicals that bind to receptors on their antennae. Only the correctly shaped molecule will fit into the receptors, stimulating an attraction. This is a demonstration of which fundamental biological concept?
The specific structure of something determines how that part interacts with other things
Which of the following statements is true about acids and bases?
Acids mixed with bases neutralize each other.
Water can absorb and store a large amount of heat while increasing only a few degrees in temperature because:
the heat must first be used to break the hydrogen bonds rather than raise the temperature.
Which of the following nucleotide bases are present in equal amounts in DNA?
guanine and cytosine
Which of the following are all monosaccharides?
glucose, fructose, and galactose
What are the essential components of all nucleotides?
Only a phosphate group, a sugar molecule, and a nitrogen-containing molecule.
Covalent bonds are bonds in which:
two atoms share electrons.
Some of the tallest broadleaf trees are called yellow poplars. The leaves at the top of this tree must get water from the poplar's roots to stay alive. What characteristic of water underlies the transport of water from roots to treetop?
Water is cohesive.
he tendency of water molecules to stick together is called:
In DNA, adenine from one strand binds to ______ in the complementary strand.
A covalent bond is formed when:
two atoms share electrons.
RNA differs from DNA with regards to the use of the nitrogenous base __ instead of __.
uracil, thymine
increase the rate at which a reaction occurs.
The most abundant molecule in the cell is
an element
is a substance that cannot be broken down chemically into any other substance.
An atom of iron has the atomic number 26. This means that:
it has 26 protons.
A buffer is a chemical that:
can quickly absorb excess H+ ions to keep a solution from becoming too acidic AND can quickly release H+ ions to counteract any increases in the OH- concentration in a solution.
chemical compound that releases H+ into a solution is called:
an acid
All of the following are lipids EXCEPT:
Most substances become more dense when frozen, but water becomes less dense. As a consequence, ice floats. What is responsible for this unusual property?
As the temperature drops and water molecules slow down, there is increasing opportunity for the hydrogen bonds to form. These bonds hold the numerous V-shaped molecules slightly farther apart than when there are no hydrogen bonds, causing the water to be less dense.
Relative to protons:
electrons have significantly less mass.
A peptide bond is a ________ bond between two __________.
covalent, amino acids
One molecule of water consists of:
one atom of oxygen covalently bonded to two atoms of hydrogen via a shared pair of electrons.
in contrast to the ______________________________ that lead to ionic bonds, covalent bonds form when __________________________.
complete transfer of electrons; two atoms share one or more pairs of outer-shell electrons
All of the following are carbohydrates EXCEPT:
spider's silk.
Phospholipids assemble spontaneously into bilayers driven by the attraction of their "tail" portions to each other and of their "head" portions to each other. The tail regions are:
Buffers are substances that minimize the changes that occur in H+ and OH- concentrations. A buffer works by accepting _______ from the solution when there is an excess and donating them when there is a deficiency.
hydrogen ions
Considering the principle of complementary base pairing, you would expect an equal ratio of which two nitrogenous bases in a DNA molecule?
cytosine and guanine
The dashed blue lines represent what kind of chemical bonding?
hydrogen bonding
All matter on earth, both living and nonliving, is made up of:
All macromolecules important in living systems contain
In an unusually detailed dissection of your dinner, you isolate an unknown fatty acid. It is a liquid at room temperature (that is, has a low melting point) and contains carbon-carbon double bonds. What are you most likely to be eating?
a plant
Phosphorus is an important nutrient for plants and animals because it is a component of:
DNA, RNA, and ATP.
Animal fats and plant oils are sometimes used as sources of fuel for automobile engines. How is energy harvested from these molecules?
They contain long chains of hydrocarbons that, when broken, release the energy stored in the bonds linking the atoms together.
Atoms become stable when:
their outermost electron shell is filled to capacity.
hat is the molecular explanation for why the sweetener Splenda is perceived by the human tongue as being sweet?
Molecules of Splenda are similar in shape and structure to sucrose.
Lactose is a combination of:
glucose and galactose.
because enzymes are proteins, they are sensitive to denaturing conditions that disrupt protein structure. Which of the following is NOT an example of a denaturing condition?
All of the above are examples of denaturing conditions.
Unsaturated fatty acid chains in membrane phospholipids help to maintain fluidity because:
they are less likely to pack tightly at lower temperatures AND they have kinks induced by extra carbon-carbon double bonds.
A balance between which two ions in aqueous solutions within organisms is critical for the proper functioning of the chemical processes of life?
H+ and OH-
Certain molecules act like bank accounts for H+ ions because they can absorb excess H+ ions to keep a solution from becoming too acidic and release H+ ions to keep the solution from becoming too basic. Such molecules are called:
water can absorb and store a large amount of heat while increasing only a few degrees in temperature. Why?
the heat must first be used to break the hydrogen bonds rather than raise the temperature.
The secondary structure of a protein refers to:
the twisting of the amino acid chain into a corkscrew-like shape or into a zigzag folding pattern.
DNA is made of:
The pH scale is a direct measure of:
the concentration of hydrogen ions in a solution.
Hydrogen bonding among water molecules gives water all of the following important properties, EXCEPT:
transparent color
a protein is a polymer of
an amino acid
rganic molecules consisting of only hydrogen and carbon are called:
A chemical compound that releases OH- into a solution is called:
an acid
The silk of a spider's web is remarkably strong, and its tensile strength is comparable to that of steel. Spider silk is a(n):
Dietary fiber is composed of:
which of the following phenomena is most likely due to the high specific heat capacity of water?
The temperature of the Santa Monica Bay, off the coast of Los Angeles, fluctuates less than the air temperature throughout the year.
Hydrogen bonds are:
the interaction between a hydrogen covalently bonded to an electronegative atom and another electronegative atom.
An atom of sodium (Na) has 11 protons. What is it's approximate atomic mass?
Why is it common for people to have dramatic weight loss when they first start on a low calorie diet?
The body breaks down glycogen with water molecules bound to it; much of the weight loss is water loss.
A partial sequence of a molecule is "AACTGCT." The molecule is:
a nucleaic acid
In terms of structural materials, _______ is to plants what _______ is to lobsters and crabs.
cellulose, chitin
How an atom bonds with other atoms is chiefly determined by:
its electrons
All of the following are proteins except:
The ingredient label on a container of shortening indicates "partially hydrogenated vegetable oil." This means that during processing the number of carbon-carbon double bonds in the oil was reduced. What is the result of decreasing the number of double bonds?
the oil is now more likely to be solid at room temperature.
Which of the following statements about living systems is NOT true?
all directly dependent on sunlight
The tertiary structure of a protein is the
unique three-dimensional shape of the fully folded polypeptide.
Within the cells of any organism, the living substance comprises a multitude of non-living components. Included in these non-living components are all of the following EXCEPT:
Which statement about phospholipids is FALSE?
Because the unsaturated fatty acid chains are easily broken they are the chief form of short term energy.