137 Questions
Which level in the biological organization hierarchy represents an increase in organizational complexity?
Tissues
What is primarily composed of atoms and molecules?
Cells
What represents a higher level of organization than tissues and organs?
Organ systems
What is the basic unit of cells?
Organelles
Which level in the hierarchy extends beyond the individual organism?
Biosphere
What is the highest level of biological organization in the hierarchy?
Biosphere
What is the mass of a neutron in one atomic mass unit (amu)?
1 amu
How many electrons are located in the innermost shell of an atom?
2
What is the term for atoms of the same element with different numbers of neutrons?
Isotopes
What is the physical half-life of a radioisotope?
The time for 50% of the radioisotope to become stable
What type of radiation do radioisotopes lose in the form of high energy particles?
Gamma rays
Why are radioisotopes used in medical imaging procedures?
To trace products of metabolic reactions involving these elements
What is the charge of an ion that has lost an electron and satisfies the octet rule?
+1
How many covalent bonds can nitrogen form?
Three
What type of bond occurs when two hydrogen atoms share a single pair of electrons?
Single covalent bond
Which type of molecule contains both polar and nonpolar regions?
Amphipathic molecule
What determines how electrons are shared in covalent bonds?
Electronegativity
In a nonpolar molecule, what type of bonds does it contain?
Nonpolar covalent bonds
Which atom has the greatest electronegativity among the 4 most common elements composing living organisms?
Oxygen
What is the simplest type of covalent bond called?
Single covalent bond
What type of bond forms between polar molecules?
Hydrogen bond
What is the function of surfactant in the lungs?
Prevents collapse of moist sacs of air
What is the term for the attraction between water molecules and a substance other than water?
Adhesion
What property of water contributes to keeping body temperature constant?
High specific heat
What is the term for the heat required for the release of molecules from a liquid phase into a gaseous phase for 1 gram of a substance?
Heat of vaporization
Which type of substances are referred to as hydrophilic?
Polar molecules and ions
What is the term for substances that do not dissolve in water?
Hydrophobic substances
What happens when water spontaneously dissociates to form ions?
'H2O' remains neutral
What does an acid do when added to water?
Increases concentration of free H+
What does a base do when added to a solution?
Accepts H+ from the solution
What term is used for molecules with polar and nonpolar regions?
Amphipathic molecules
What are substances that remain intact but do not conduct current when dissolved in water?
Nonelectrolytes
What is the pH range for plain water?
0 to 14
What happens to the pH as the concentration of H+ ions increases?
pH increases
What is the primary function of buffers in the body?
To maintain pH within a critical range
What is the characteristic of a suspension?
Appears cloudy or opaque
Which category of mixture has particles smaller than those in a suspension but larger than those in a solution?
Colloid
What does molarity express?
Moles solute per liter solution
What do osmolarity and osmolality measure?
Number of particles in a solution
What is the unit of measurement for the number of particles in a solution?
Osmoles
Which molecule is central in the transfer of chemical energy within a cell?
'ATP'
What occurs when water and carbon dioxide combine?
Producing H2CO3 (carbonic acid)
What happens if there is an excess of H+ ions or OH- ions in the body?
Buffers help maintain pH within a critical range
What happens to molarity with changes in temperature?
It remains constant
Which level in the biological organization hierarchy is primarily composed of cells?
Tissues
What is the highest level of biological organization in the hierarchy?
Biosphere
At which level in the hierarchy do macromolecules exist?
Cells
Which category of matter includes blood?
Liquid
What represents an increase in organizational complexity beyond tissues and organs?
Organ systems
At which level in the hierarchy do atoms and molecules exist?
Atoms
How many electrons does oxygen need to complete its outer shell?
Two electrons
What type of covalent bond forms when two nitrogen atoms share three pairs of electrons?
Triple covalent bond
Which atom forms four covalent bonds?
Carbon
What is the term for large molecules with both polar and nonpolar regions?
Amphipathic molecules
What determines how electrons are shared in covalent bonds?
Electronegativity
Which type of covalent bond involves the sharing of one pair of electrons?
Single covalent bond
What is the characteristic of nonpolar molecules?
They contain nonpolar covalent bonds
What type of bond occurs between two oxygen atoms when they share two pairs of electrons?
Double covalent bond
What is the term for weak chemical attractions between molecules that are important for the shape of complex molecules?
Van der Waals interactions
In a periodic table, what increases from left to right across a row?
Electronegativity
What is the term for large molecules with both polar and nonpolar regions?
Amphipathic molecules
Which type of bond occurs when carbon atoms bond with hydrogen atoms?
Nonpolar covalent bond
What is the pH range for plain water?
7-10
How does the pH change as the concentration of H+ ions increases?
pH decreases
What is the unit of measurement for the number of particles in a solution?
Osmolarity
What does molarity express?
Mass per volume
What determines how electrons are shared in covalent bonds?
Electronegativity
What happens if there is an excess of H+ ions or OH- ions in the body?
Decreased pH
What represents a higher level of organization than tissues and organs?
Organisms
What is primarily composed of atoms and molecules?
Cells
What occurs when water and carbon dioxide combine?
Formation of carbonic acid
What do osmolarity and osmolality measure?
Number of particles in a solution
What property of water contributes to keeping body temperature constant?
High heat capacity
What type of bond forms between polar molecules?
Hydrogen bond
What type of bond forms between polar molecules?
Hydrogen bond
What term is used for molecules with polar and nonpolar regions?
Amphipathic molecules
What property of water contributes to keeping body temperature constant?
High specific heat
What is the term for the attraction between water molecules and a substance other than water?
Adhesion
What represents the phases of water depending on temperature?
Liquid, solid, gas
Which type of substances are referred to as hydrophilic?
Polar molecules and ions
What is the term for substances that do not dissolve in water?
Hydrophobic substances
Which level in the hierarchy extends beyond the individual organism?
Ecosystems
What type of bond occurs when two hydrogen atoms share a single pair of electrons?
Nonpolar covalent bond
What property of water causes the inward pulling of cohesive forces at the surface of water?
Cohesion
What component prevents the collapse of moist sacs of air in the lungs?
Lipoprotein
What is the unit of measurement for the number of particles in a solution?
Molality (m)
What represents the number of protons in an atom of an element?
Atomic number
What are isotopes of an element differentiated by?
Atomic mass
What do radioisotopes contain in excess, making them unstable?
Neutrons
What is the physical half-life of a radioisotope?
The time for 50% of radioisotope to become stable
Which ion is used in some states for lethal injection?
K+
What charge does an anion have?
-1
What type of bond forms between sodium and chlorine in table salt (NaCl)?
Ionic bond
What term is used for the attraction between water molecules and a substance other than water?
Hydrogen bond
What do covalently bonded molecules involve?
Sharing of electrons between atoms
What does the structural formula of a molecule indicate?
The arrangement of atoms within the molecule
What type of elements do molecular compounds involve?
Different elements sharing electrons
What is the term for the weak chemical attractions between molecules that are important for the shape of complex molecules?
Hydrogen bonds
How many covalent bonds can carbon form?
Four
What type of bond occurs between two nitrogen atoms when they share three pairs of electrons?
Triple covalent bond
What is the term for molecules with both polar and nonpolar regions?
Amphipathic molecules
What determines how electrons are shared in covalent bonds?
Electronegativity
Which type of covalent bond involves the sharing of one pair of electrons?
Single covalent bond
Which level in the hierarchy represents an increase in organizational complexity?
Organs
What is the term for the highest level of biological organization in the hierarchy?
Biosphere
What represents a higher level of organization than organs?
Organ systems
At which level in the hierarchy do atoms and molecules exist?
Cells
What is the term for the attraction between water molecules and a substance other than water?
Hydrogen bond
What occurs when water spontaneously dissociates to form ions?
Production of hydrogen ions and hydroxide ions
What is the mass of a neutron in one atomic mass unit (amu)?
Approximately 1 amu
What is the charge of an ion that has lost an electron and satisfies the octet rule?
+1
Which type of substances are referred to as hydrophilic?
Substances that dissolve in water
What occurs when water spontaneously dissociates to form ions?
Formation of hydronium ions
What is the physical half-life of a radioisotope?
Can vary from a few hours to thousands of years
What is the characteristic of a suspension?
Particles do not settle out over time
What happens to the pH as the concentration of H+ ions increases?
pH decreases
What happens if there is an excess of H+ ions or OH- ions in the body?
Disturbance in pH balance
What type of bond forms between polar molecules?
Hydrogen bond
What is the term for nonpolar molecules placed in a polar substance?
Hydrophobic interactions
What constitutes two-thirds of the human body by weight?
Water
What is the measure of kinetic energy of atoms or molecules within a substance?
Temperature
Which substances dissolve in water are called 'universal solvents'?
Polar molecules and ions
What occurs when water spontaneously dissociates to form ions?
Equal numbers of positive and negative ions produced
What is the term for a substance that donates protons when dissolved in water?
Acid
What represents a higher level of organization than tissues and organs?
Organisms
What type of bond occurs when two hydrogen atoms share a single pair of electrons?
Covalent bond
What term is used for weak chemical attractions between molecules that are important for the shape of complex molecules?
Van der Waals forces
What represents a higher level of organization than tissues and organs?
Tissues
What does the structural formula of a molecule indicate?
The arrangement of atoms within the molecule
What is the pH range for plain water?
pH 7
What category of mixture has particles smaller than those in a suspension but larger than those in a solution?
Colloid
What represents a 10-fold change in H+ concentration on the pH scale?
Moving from pH 6 to pH 7
What is the unit of measurement for the number of particles in a solution?
Osmole
What is the primary function of buffers in the body?
To maintain pH
What type of bond forms when two hydrogen atoms share a single pair of electrons?
Covalent bond
What occurs when water and carbon dioxide combine?
Formation of carbonic acid
What is the term for molecules with both polar and nonpolar regions?
Amphiphilic molecules
Test your knowledge about covalent bonds, where atoms share electrons to complete their outer shells. Learn about the number of covalent bonds an atom can form and which elements commonly form covalent bonds in the human body.
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