biology 1 midterm
The typical oxygen atom is described in the periodic table by the accompanying box. How many protons are in a typical oxygen atom?
8
While the maximum number of electrons required to fill the outermost shell of an atom varies depending on the size of the atom, almost all of the smaller atoms (atomic numbers 2-20) are considered stable, and thus nonreactive, when they contain ________ electron(s) in the outermost shell.
8
How do buffers minimize change in the pH of biological systems?
By donating H+ ions when there is a shortage. By absorbing H+ ions when there is an excess
Identify the reactants in the following chemical reaction: C10H8 + 12 O2 →→ 10 CO2 + 4 H2O
C10H8 and 12 O2
What are the four classes of large organic molecules important to life on Earth?
Carbohydrates, proteins, lipids, and nucleic acids
Why are all living organisms based on molecules that contain carbon?
Carbon atoms can form bonds with up to four other atoms.
Which of the following statements regarding chemical reactions is false?
During a chemical reaction, atoms of one element can be converted into a different element.
Which of the following represents a simple sugar (also called a monosaccharide)?
Glucose
An acid is a compound that donates _______ to a solution.
H+
Fire can move, grow, reproduce, use energy, consume oxygen, and interact with its environment. Why is it not alive?
It does not consist of complex, well-ordered structures.It does not have cells.It does not pass on genes for traits to its offspring.
A research team designs an experiment to increase the speed of athletes. The athletes' diet and sleep routines are altered for two weeks. Is this an example of a controlled study?
No. A controlled study only changes one variable at a time
The higher the pH number, the higher the concentration of _______ in a solution
OH-
What is the most common element in your body?
Oxygen
a property of all living things
Reproduces its own kind Takes in, converts, and expels energy Complex, but well-ordered, structure Responds to the environment Populations evolve over time
not a property of all living things
Requires another individual to reproduce Eats other organisms to gain energy Composed of many cells Individuals evolve over time
Which would have the highest concentration of C−HC−H bonds?
Saturated fat
Food processors are phasing out the use of which types of fats, because research has shown them to be particularly unhealthy?
Saturated fats and trans fats
Skin is sometimes referred to as the largest organ of the body. Why is skin considered to be an organ and not a tissue or some other structure?
Skin consists of multiple tissue types that cooperate to perform a specific task.
Which of the following properties of water molecules has important implications to life?
The ability to dissolve polar substancesHigh surface tensionThe ability of ice to float in water
What might happen if a protein has a change in one amino acid?
The amino acid chain folds incorrectly. The protein has a new shape. The protein can no longer function properly.
A needle can be made to "float" on the surface tension of water. What causes this surface tension to form?
The cohesion of water molecules to each other
Select the most complete explanation of what the pH scale measures.
The concentration of hydrogen ions in an aqueous solution
Many medical studies show that patients who receive a treatment feel better even if the treatment was an ineffective sugar pill. What is this phenomenon called?
The placebo effect
To a large extent, a protein's function is dependent upon its shape. What determines a protein's shape?
The sequence of amino acids
What is the core theme that unifies all of biology?
The theory of evolution by natural selection
What are isomers?
Two molecules that have the same atoms arranged differently
What is responsible for the unusual chemical properties of water?
Water molecules can form an extensive network of hydrogen bonds with one another.
A polypeptide is ________.
a long chain of amino acids
he term for a solution with a low pH number, such as lemon juice or vinegar, is ________
acidic
Enzymes speed up chemical reactions by lowering the ___________which allows the reaction to proceed much more quickly.
activation energy
The specific location within an enzyme molecule where the substrate binds is called the _________
active site
What are the monomers of proteins?
amino acids
The smallest unit of matter that retain all of the physical properties of that type of matter is a(n) -----
atom
_____________ is the number of protons in the nucleus of an atom, which determines the chemical properties of an element and its place in the periodic table.
atomic number
The number of protons plus neutrons in an atom, represented as an average of all naturally occurring forms of the element, is known as ______________
atomic weight
The term for a solution with a high pH number, such as ammonia or bleach, is __________
basic
A substance that accepts H+ when they are in excess and donates H+ when their concentration drops is called a(n) _______
buffer
__________ is one of the seven elements that make up a small fraction, approximately 3.7%, of living cells.
calcium
Organic compounds are distinguished by molecules that contain ________ bonded to other elements.
carbon
The scientific study of matter is called _________
chemistry
A ____________ establishes a base line for an experiment
control group
The type of test that changes only one variable at a time in order to isolate the results is known as a _______ experiment
controlled
A(n) _________ bond involves the sharing of electron pairs between atoms, also known as a molecular bond.
covalent
The building of a large organic molecule from small subunits involves multiple ________.
dehydration synthesis reactions
The __________ variable is the factor a scientist observes to see the effect of the change made
dependent
When two pairs of electrons are shared between two atoms, a _________ bond is formed.
double
In a ________ experiment, neither the participants nor the researchers know who receives the treatment and who does not
double blind
H2SO4, sulfuric acid, contains three different types of atoms: hydrogen (H), sulfur (S), and oxygen (O). Each of these atoms represents a different ______. Since the three types are combined in a fixed ratio, this means that H2SO4 is a(n) ________
element, compound
Lactose takes years to break down on its own. But if exposed to the protein lactase, the reaction proceeds very quickly, while lactase itself remains unchanged. Lactase is an example of a(n) __________
enzyme
The 2+ in Cu2+ tells us that this atom ________
has two more protons than electrons
A weak bond called a __________bond results from an attraction between a slightly positive region in a molecule and a slightly negative region in the same or a different molecule
hydrogen
The breaking of a large organic molecule into smaller, individual subunits involves multiple ________.
hydrolysis reactions
All lipids are ________.
hydrophobic
The one variable that is manipulated by a scientist as a potential cause in an experiment is the __________ variable
independent
A(n) _________ is a molecule that can bind to an enzyme and prevent the enzyme from working. There are two types: a(n) ____________ binds to the active site of the enzyme; a(n) _____________ binds elsewhere on the enzyme
inhibitor, competitive inhibitor, noncompetitive inhibitor
A(n) _______ bond forms when one atom gives up one or more electrons to another atom
ionic
Atoms or molecules with a net electric charge due to the loss or gain of one or more electrons are _______
ions
In an atom, the number of neutrons determines most specifically the ________.
isotope
How is life defined?
life is defined through a set of shared characteristics that all living things display
__________ is anything that occupies space and/or has any substance.
matter
If two or more atoms are bonded together, they form a(n) _________
molecule
whats the sequence of the biological organization smallest to largest?
molecule, cell, tissue, organ, organism, population, community, ecosystem, biosphere
A _____________ is a group in which no response is expected
negative control
The term for a solution that has an equal concentration of H+ and OH- is __________
neutral
is one of the four elements that make up 96.3% of living cells.
nitrogen
Atoms involved in a _____________ bond equally share electrons; there is no charge separation to the molecule.
nonpolar
A ________ bond is a type of chemical bond where a pair of electrons is unequally shared between two atoms. As a result, one end of the molecule has a slightly negative charge and the other a slightly positive charge.
polar
The statement, "There are 628 gray squirrels living on campus," describes the ________ of gray squirrels on campus.
population
A ____________ is a group in which a known response is expected.
positive control
During digestion, __________ are broken down into __________ through __________ reactions.
proteins; amino acids; hydrolysis
The atomic number corresponds to the number of ________ in a specific element, while the atomic weight corresponds to the number of ________ in a specific element.
protons; protons and neutrons
Within a plant, water (H2O) and carbon dioxide (CO2) can be combined (using the energy of sunlight) to produce glucose (C6H12O6) and oxygen (O2). If you were to write out this chemical reaction, water and carbon dioxide are each an example of a(n) ______ while glucose and oxygen are each an example of a(n) ________
reactant, product
During a chemical reaction, atoms are ________.
rearranged
When one pair of electrons is shared between two atoms, a _________ bond is formed
single
In a __________experiment, the researchers--but not the participants--know who receives the treatment and who does not, to eliminate subjective bias.
single blind
During an enzymatic reaction, a molecule of __________ binds to the enzyme and is broken down into one or more molecules of ________, which are released
substrate, product
______________ also called micronutrients, are any chemical element required by living organisms in miniscule amounts, but cells require them to survive.
trace elements
___________ is one of the fourteen trace elements and is a component of certain digestive enzymes and other proteins.
zinc