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