CHAPTER 2 - PHYSIOLOGY EXAM 1
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60 Terms
What is the smallest unit of an element?
An atom.
What particles are in the nucleus of an atom?
Positively charged protons and uncharged neutrons.
Where are electrons located?
Orbiting the nucleus in shells or orbitals.
How is atomic mass calculated?
Protons + Neutrons.
What does the atomic number represent?
The number of protons.
How many protons, neutrons, and electrons does carbon have?
6 Protons
6 Neutrons
6 Electrons.
How many protons and electrons does hydrogen have?
1 proton, 1 electron
What is another name for electron shells?
Orbitals
What is the maximum number of electrons in the first shell?
2 electrons
What is the maximum number of electrons in each shell after the first (in biological elements)?
8 electrons.
When is an atom most stable?
When its outer shell is full.
What are valence electrons?
Electrons in the outer shell that participate in bonding.
What are isotopes?
Atoms of the same element with different numbers of neutrons.
Do isotopes have the same atomic number?
Yes, but different atomic masses.
What are radioactive isotopes used for?
Medical testing and physiological research.
What determines the number of bonds an atom can form?
The number of valence electrons.
How many bonds can hydrogen form?
One bond
How many bonds can carbon form?
Four bonds
What is a covalent bond?
A bond formed when valence electrons are shared between atoms.
What is a nonpolar covalent bond?
Electrons are shared equally between atoms.
Give an example of a nonpolar covalent bond.
Two hydrogen atoms sharing electrons (H2).
What is a polar covalent bond?
Electrons are not shared equally, creating partial positive and negative ends.
Give an example of a polar covalent bond.
Oxygen and hydrogen atoms in water.
Is water polar or nonpolar?
Polar
Why is water a good solvent?
Its polarity allows it to dissolve many substances.
What is hydrophilic?
Molecules that are polar and dissolve in water.
What is hydrophobic?
Molecules that are nonpolar and do not dissolve in water.
What is an ionic bond?
A bond formed when one atom gives electrons to another.
What is a cation?
An atom that loses electrons and becomes positively charged.
What is an anion?
An atom that gains electrons and becomes negatively charged.
What happens to ionic compounds in water?
They dissociate into ions and form hydration spheres.
Why are free ions important?
They are critical for many physiological processes.
What happens when NaCl is dissolved in water?
Na+ and Cl- ions separate and become surrounded by water molecules.
What is a hydrogen bond?
A weak attraction between polar molecules due to opposite charges.
What atoms are commonly involved in hydrogen bonds?
Electropositive hydrogen and electronegative oxygen or nitrogen.
What is one function of hydrogen bonds in water?
They create surface tension and allow capillarity.
What is one function of hydrogen bonds in proteins?
They help form the protein's 3D shape.
What is one function of hydrogen bonds in DNA?
They hold the two strands together.
What is the pH of a neutral solution?
7
What is an acid?
A solution with more H+ ions than OH- ions
pH below 7 (acidic)
What is a base?
A solution with more OH- ions than H+ ions
pH above 7 (alkaline).
What is the pH range of the scale?
0 (strongest acid) to 14 (strongest base).
How is pH calculated?
pH = -log(H+ concentration).
If pure water has an H+ concentration of 10^-7, what is its pH?
7
How much more acidic is a solution with pH 6 than pH 7?
10 times more acidic.
What condition occurs if blood pH falls below 7.35?
Acidosis
What condition occurs if blood pH rises above 7.45?
Alkalosis
What is a buffer?
A substance that stabilizes pH in a solution.
What two components make up a buffer pair?
A weak acid and a weak base.
What are the main buffers in blood?
Bicarbonate ion (HCO3-) and carbonic acid (H2CO3).
What does bicarbonate do?
Neutralizes excess acid.
What does carbonic acid do?
Neutralizes excess base.
Write the buffer equation in blood.
HCO3- + H+ ↔ H2CO3.
What elements are in organic molecules?
Carbon and hydrogen
Why can carbon form chains and rings?
Because it can make 4 bonds
What is a double bond?
When two carbons share two pairs of electrons.
What types of organic molecules exist in biology?
Proteins
Lipids
Carbohydrates
Nucleic Acids
Example of a carbohydrate polymer?
Starch or glycogen.
Example of a nucleic acid?
DNA or RNA.
Example of a lipid?
Fatty acids