Chapter 2 Flashcards
Biochemistry
matter
anything that takes up space and has mass
mass
a measure of the amount of matter an object contains
weight
a measure of how strongly an object is pulled by earth’s gravity. Can vary with the distance from the earth’s center
element
a substance that cannot be broken down into other substances by chemistry
molecule
a substance consisting of atoms held together by covalent bonds
compound
a substance composed of 2 or more elements combined in a fixed ratio
What are the “big 6” elements and their symbols?
- C – Carbon
- H – Hydrogen
- N – Nitrogen
- O – Oxygen
- P – Phosphate
- S – Sulfur
Name 6 other elements as discussed in lecture
- Cl – Chlorine
- Fe – Iron
- Na – Sodium
- K – Potassium
- Ca – Calcium
- Zn – Zinc
atom
the smallest unit of matter that still keeps the physical and chemical properties of its element
What are the subatomic particles of an atom, their charges, and their location?
Neutron - no charge - nucleus - 1 dal
Proton - +1 - nucleus - 1 dal
Electron - -1 - electron shell, orbital level - 1/2000 of 1 dal
atomic number
the number of protons in an atom of a particular element
- the number is unique for each element.
- if neutral atom, protons and electrons are equal
mass number
the number of protons and neutrons in an atom
- can be used to determine the number of neutrons by subtracting the atomic number from this number
molecular weight/ mass
the sum of atomic masses/weights of all the atoms in a molecule
- expressed in units of daltons or A.M.U. (atomic mass units)
isotopes
atoms of an element that have the same atomic number, but different mass numbers
- different mass because different number of neutrons
- some can be radioactive
Which subatomic particle is directly involved in chemical reactions?
electrons (e-) because they are in the electron shell
What are the rules for energy shells and electrons?
- max of 2 electrons in the innermost electron shell
- electrons must occupy innermost shell first before filling the next
- 2nd can hold 8 electrons (rest can too)
- atoms will attempt to have a full shell of electrons (octet rule)
Name the types of chemical bonds
- Covalent bond
- Ionic bond
- Weak bonds (hydrogen bonds)
Covalent bonds
occurs when electrons are shared
- very strong
- can be single, double, or tripled based on pairs of electrons shared.
What are the types of covalent bonds?
Nonpolar- equal electron sharing
Polar - unequal electron sharing.
Ionic bonds
- formed by complete transfer of an electron from 1 atom to another
- forms salts (NaCl)
ion
a charged atom or molecule
anion
a negatively charged ion (gains an electron)
cation
a positively charged ion (loses an electron)
hydrogen bonds
Hydrogen atom covalently bonded to one atom but is attracted to another
heat
the total kinetic energy due to molecular motion in a body of matter
temperature
- measure of heat intensity to the average kinetic energy of molecules in a body of H2O
- heat passes from warmer objects to cooler objects
calorie (cal)
the amount of heat needed to raise the temperature of 1 g of water by 1 C
Why does H2O have a fairly high specific heat?
It takes a great deal of energy to break apart the hydrogen bonds that connect different water molecules
Vaporization / evaporation
the transformation of a substance from a liquid to a gaseous state
Heat of vaporization
the quantity of heat a liquid must absorb for 1 gram to be converted to the gaseous state
- H2O has a high _____ ___ _________
~540g
Why is water important to the body?
- it is a very good solvent
- water can gain or lose a great deal of heat without major changes in its own temperature
- used to help build up or break down many different compounds
- exhibits cohesion: the linking of 2 molecules to another of the same type usually with Hydrogen bonds
Due to the hydrogen bonding, water is _____ dense as a solid than as a liquid.
less
evaporative cooling
the cooling of a liquid’s surface when the liquid changes to a gaseous state
solution
a liquid that is a homogenous mixture of 2 or more substances
solvent
the dissolving agent of a solution (dissolver)
solute
the substance dissolved in the solution
hydrophilic
“water loving” has a strong affinity (attraction) for water
hydrophobic
“water fearing”
term used to describe a condition where water is repelled
molecular weight/mass
the sum of the atomic masses/weights of all the atoms in the molecule
Expressed in units of daltons and A.M.U. (atomic mass unit)
mole
the amount of a substance that has a mass in grams equivalent to its molecular mass/weight in daltons
Avogadro’s number
A mole of 1 substance has the same number of molecules as a mole of another
=6.022x10623
Molarity (M)
the number of moles of solute per L of solution
acid
a substance which breaks apart in solution to release or donate hydrogen ions
base
a substance which removes hydrogen ions from a solution
pH
the concentration of H+ ions in a solution = -log[H+]
pH ____ when the acidity level _____
- decreases, increases
- increases, decreases
buffer
a substance that can stabilize pH by either removing or releasing H+ into the solution as needed.
salts
inorganic compounds that dissolve in water, but do not release H+ or OH-
- Held together by ionic bonds
hydroxyl group
R–OH-
Alcohols
carboxyl group
O
ll
R–C–OH
Carboxylic acids
Amino group
H
l
R–N–H
Amines
sulfhydryl group
R–SH
Thiols
phosphate groups
O
ll
R--O--P--O-
l
O-
organic phosphateMethyl group
H
l
R--C--H
l
H
methyl (methylated)
carbonyl group
O
ll
R–C–R
Ketone or Aledhyde
Carbohydrates
- composed of C, H, and O atoms in a fixed ratio of 1:2:1
- Basic building blocks are simple sugars known as monosaccharides
