Human Bio Ch. 2
Proteins that speed up the rate of a chemical reaction are
enzymes
Non-polar covalent bonds mean
equal sharing
Each carbon atom can share pairs of electrons with as many as ____ other atoms.
four
Polar covalent bonds mean
not equal sharing
A _____ is composed one sugar, a phosphate, and a nitrogen base.
nucleotide
A dissolved substance in water is a(n)____.
solute
The most common polysaccharides are glycogen and
starch
What is the maximum number of electrons in a shell?
8
(T/F) Water is liquid because of the strength of the hydrogen bonds that hold the hydrogen of one water molecule and the oxygen of another together.
True
Covalent bonds ____.
are extremely strong and stable
A blood pH below 7.3 is known as
acidosis
The sequence of amino acids of a protein is its ______ structure.
primary
An antioxidant is a chemical that gives up a(n)
electron
The term ______ means a pure substance that cannot be broken down.
element
Electrons travel around the nucleus of an atom in _____ levels.
energy
Molecules such as water are referred to as _____ because they are electronically neutral overall but still have partially charged regions.
polar
(T/F) An acid is a substance that donates protons when dissolved in water and a base is a substance that accepts protons when it dissolves in water.
True
(T/F) Carbohydrates are used by cells to store energy.
True
(T/F) Energy emissions from radioisotopes are used in medicine to help visualize internal body processes.
True
(T/F) Nucleotides are energy-carrying molecules.
True
(T/F) The shape of a protein determines its function.
True
What are the major molecules that make up our body?
(CHON) Carbon, Hydrogen, Oxygen, and Nitrogen
What forms a bilayer structure that is found in cell membrane?
phospholipids
A free radical is missing a(n)
electron
Low hydrogen ion concentration means a _____ pH value.
High pH value
A substance that accepts H+ when dissolved in water is a(n)
base
During a hydrolysis reaction, ____.
bonds are broken
When a person's blood sugar falls glycogen is
broken down
A _____ system resists changes in pH.
buffer
Organic molecules contain at least one hydrogen atom and
carbon
Organic molecules are held together by
covalent bonds
An isotope with an unstable nucleus undergoes radioactive
decay
The building block of large carbohydrates is ____.
glucose
Water has a _____ heat capacity.
high
The simplest form of an atom is
hydrogen
A _____ reaction involves breaking bonds.
hydrolisis
Molecules that can interact with water are
hydrophilic
OH- is known as a(n) _____ ion.
hydroxide
The various forms of an element are known as
isotopes
The blending of two or more kinds of molecules is a(n)____.
mixture
The bonding of two or more atoms creates a(n) ____.
molecule
Chemical bonds turn atoms into
molecules
There is a slight ______ charge on the oxygen atom in a water molecule.
negative
The nucleus of an atom is composed of protons and
neutrons
The atomic number denotes the number of ____ in an atom of a particular element.
protons
A compound that releases ions other than hydrogen and hydroxide is a(n)
salt
A _____ is a dissolved substance.
solute
Plants store large amounts of carbohydrates in the form of ____.
starch
The _____ structure of a protein determines its function.
tertiary
A solution has been prepared by mixing glucose in water. What correctly describes this solution?
water is the solvent, glucose is the solute
A solution with equal amounts of hydrogen and hydroxide ions has a pH of
7
_____ is the molecule that determines the order of amino acids that makes up a protein.
DNA
(T/F) A protein is a molecule composed of a chain of fatty acids.
False
(T/F) Antioxidants attract electrons from other stable molecules.
False
(T/F) Oil and water do not mix because oils are polar and water is nonpolar.
False
(T/F) When an atom of an element contains a different number of neutrons than usual, it is called a nucleotide.
False
Which statement is true of electron shells?
The innermost shell can hold up to two electrons.
How do hydrophilic molecules interact with water?
They are attracted to water
A buildup of H+ in the blood will lead to ____.
acidosis
An amine functional group contains
nitrogen
The bond between two amino acids in a protein is a(n)
peptide bond
In PET scanning, the patient is injected with a(n) ______, a molecule in which radioisotopes have been substituted for some atoms.
tracer
The first energy level can hold up to ______ electrons
two