Chapter 2 Quiz
The pH scale goes from ______ to______. A pH of 7 is considered________, a pH <7 is considered ________, and a pH >7 is considered_________.
0; 14; neutral; acidic; basic
There are _____ different amino acids.
20
How many electrons does carbon (atomic number = 6) contain in its first and second valence shells?
2;4
Potassium (K) has an atomic number of 19, and it has 20 neutrons. What is its atomic mass?
39
How many electrons does carbon (atomic number = 6) contain in its outer valence shell?
4
What is the maximum number of atoms to which a single carbon can bind?
4
Glucose (a monosaccharide) has the molecular formula c6h1206. How many carbon atoms are in each glucose molecule
6
Which of the following is NOT a property of water?
All biological molecules will dissolve in water
Which of the following statements about neutrons is CORRECT?
All neutrons are found in the nucleus of the atom
A cell is unable to take up or make sugars. Which molecules will it be unable to take up or make
Carbohydrates and nucleic acids
Identify the smallest subunits of life that can also sometimes be considered living organisms on their own
Cells
The bond between the oxygen atom and a hydrogen atom in a water molecule is a(n) ____________ bond)
Covalent
An example of a nucleic acid is
DNA
As an acidic compound dissolves in water the pH of the water ___________
Decreases
humans ability to shiver is an attempt to increase the body's internal temperature and maintain ______
Homeostasis
What makes ice less dense than liquid water?
Hydrogen bonds between water molecules expand when solid
Which part of the cell membrane acts as a barrier to hydrophilic molecules
Hydrophobic tails
Polar bears rely on Arctic ice sheets and icebergs on the surface of water as a part of their habitat. How would the habitat of polar bears be affected if solid water was more dense than liquid water?
Ice would sink rather than float, so there would be no ice sheets or ice bergs.
Why do salt crystals form in a pan of seawater from which the water has been evaporated?
In the absence of water, sodium and chloride form ionic bonds and aggregate into crystals.
When an atom loses an electron, what happens
It becomes positively charged
When an atom loses an electron, what happens?
It becomes positively charged.
Why is a cell membrane like a phospholipid sandwich?
It is a two-layered semipermeable structure with heads on the outside, tails in the middle, and heads on the inside.
How are lipids unique when compared to other macromolecule groups
Lipids do not contain monomers and they are comprised of compounds
What are the four types of organic molecules that make up all living things on earth
Lipids, nucleic acids, carbohydrates, proteins
The ability to ____ is not a generally recognized characteristic of most (if not all) living organisms
Obtain energy directly from sunlight
Which of the following lists the most abundant elements in the human body from most abundant to least abundant?
Oxygen→carbon→hydrogen→nitrogen
Where are the protons, neutrons, and electrons located in an atom?
Protons and neutrons are located in the nucleus, and electrons are located in orbitals.
____ make up the nucleus of an atom, whereas _____ surround the nucleus
Protons and neutrons; electrons
Which of the following does not give researches hope that life may exist on mars
Rovers have captured images of bacterial cells within rocks
If coffee has a pH of 5 and soda a pH of 4, which is more acidic and by how much?
Soda is 10 times more acidic than coffee
Coffee or tea with sugar dissolved in it is an example of a water based solution. Coffee in this case is the _________ sugar is the ____________ and this means that the sugar molecules must be _____________
Solvent; solute; hydrophobic
Which of the characteristics of life does a virus display, even though its characterization as being alive is controversial
The abilities to reproduce and grow
Why is the phospholipid bilayer considered semipermeable?
The bilayer is a barrier to some, but not all, substances on either side of it.
How does the molecular structure of a water molecule affect its polarity?
The oxygen has a partial negative charge and the hydrogens have a partial positive charge, yielding a weakly polar water molecule that can form hydrogen bonds.
How does water dissolve table salt?
Water is a polar molecule that disrupts ionic bonds between sodium and chloride.
Which of the following are most likely to dissolve in olive oil?
a nonpolar molecule
Which of the following is/are most likely to dissolve in olive oil?
a nonpolar molecule
Which statement describes a hydrogen bond between two water molecules?
a weak bond between the slightly negative oxygen atom of one water molecule and the slightly positive hydrogen atoms of another water molecule
A solution with a pH less than 7 is called a(n) _____________ and has a higher number of ___________ than a solution with a pH greater than 7.
acid; H+
The smallest unit of an element that still retains the property of an element is
an atom
Elements are ordered in the periodic table by their
atomic number or proton number.
The cell membrane is made of
both proteins and phospholipids.
Which of the following is considered an inorganic molecule?
carbon dioxide
The basic building blocks of life are
cells.
The _____ of water molecules explains how some insects can walk on water.
cohesion
The surface tension of water is an example of
cohesion
The attraction water molecules have for other water molecules is called _____________, whereas the attraction water molecules have for non-water molecules is called _____________.
cohesion; adhesion
In a water molecule, the bond between the oxygen atom and a hydrogen atom is a(n) ___________ bond.
covalent
As an acidic compound dissolves in water, the pH of the water
decreases
The atomic particles responsible for forming bonds with other atoms are
electrons
Which part of an atom forms covalent bonds with other atoms?
electrons in the outermost energy shell
In terms of bond strength which of the following is the weakest
hydrogen
The "stickiness" of water results from the ______________ bonding of water molecules.
hydrogen
the "stickiness" of water results from the _____________ bonding of water molecules
hydrogen
Which part of a cell membrane phospholipid is exposed to the aqueous (watery) exterior?
hydrophilic head
Which part of a cell membrane phospholipid is exposed to the aqueous (watery) interior?
hydrophilic head
Olive oil is ___________ because ________
hydrophobic; it does not interact with water
All of the following are true of water EXCEPT
it is a polarized molecule, where the oxygen is slightly positive and the hydrogens are slightly negative.
Which of the following macromolecules are insoluble in water
lipids
If life exists on Mars, what form is it likely to be?
microscopic
Which of the following is NOT a functional trait of a living organism?
moving from place to place
The cell membrane is made of ___________
phospholipids and proteins
In addition to carbon, hydrogen, oxygen, and nitrogen, which elements make up the bulk of the human body?
phosphorus and calcium
In a water molecule, hydrogen atoms are bonded to oxygen by _________ bonds, whereas neighboring water molecules are held together by __________ bonds.
polar covalent; hydrogen
Atoms are made up of
positively charged protons, negatively charged electrons, and neutral neutrons.
Which trait is NOT a functional characteristic of all living things?
protect self from predators
A collection of amino acids could be used to build a
protein.
For an element to have no charge, which must be equivalent in number?
protons and electrons
When a plant bends toward sunlight, the bending is an example of which characteristic of life?
responding to their environment
Which of the following statements about carbon is false
soil samples containing carbon must contain life
When making sugar water, the sugar is the _____________ whereas the water is the ___________.
solute; solvent
Lipids may function in all of the following ways EXCEPT
structural support.
An ion can be formed by
the loss or gain of an electron.
The atomic mass is equal to
the number of protons plus the number of neutrons.
A covalent bond is formed by
the sharing of electrons between atoms.
All of the following are true of phospholipids EXCEPT
the tails of the molecule are hydrophilic.
All of the following are true of proteins EXCEPT
they serve as energy-storage molecules.
Which is an example of a molecule that has polar covalent bonds?
water
