Exam 2 (Ch. 2 Chemistry) Flashcards
define molecule and give 1 example
molecules are formed from 2 or more atoms, ex: O2
define atom
the smallest component of a pure substance
what is the charge of a proton? location in the atom?
positive; nucleus
what is the charge of a neutron? location in the atom?
neutral; nucleus
what is the charge of an electron? location in the atom?
negative; outside the nucleus
define a chemical element
all atoms with the same number of protons that behave the same way chemically
define a compound and give an example
a molecule that contains at least 2 different kinds of atoms, ex: H2O
why do molecules hold together
because the valence electrons of the combining atoms form attractive forces called chemical bonds
how do atoms form bonds
by either gaining or losing electrons or by sharing electrons
define ion
a negatively or positively charged atom or atoms
define ionic bonding and give an example
an attraction between ions of opposite charge that hold them together to form a stable molecule, ex: sodium chloride
define cation and give 3 examples
positively charges ions; ex: potassium, calcium, sodium
define anion and give 2 examples
negatively charges ions; ex: iodine, chlorine, sulfur
define a covalent bond
a chemical bond formed by 2 atoms sharing one or more pairs of electrons. They are stronger and more common than ionic bonds
define hydrogen bond
this occurs when a hydrogen atom is covalently bonded to one oxygen or nitrogen is attached to another nitrogen or oxygen atom. Hydrogen bonds are the weakest bonds and the easiest to break of all bonds
define energy
the ability to do work
define kinetic energy
energy in motion
define potential energy
the energy an object has because of its position
chemical energy occurs whenever…
bonds between atoms are formed or broken during chemical reactions
synthesis (anabolic) reaction (3 things)
- a reaction that builds new molecules
- energy is required (endergonic)
- ex: ADP+P -> ATP
decomposition (catabolic) reaction (3 things)
- a reaction that breaks down molecules
- energy is released (exergonic)
- ex: ATP -> ADP + P
example of an exchange reaction
NaOH + HCl -> NaCl + H2O
define enzyme
a chemical that catalyzes or speeds up a reaction
ATP stands for
adenosine triphospate
ATP is a type of
potential or stored energy
when ATP is broken down energy is
released
define inorganic compound
molecules, usually small and structurally simple which typically lack carbon and in which ionic bonds may play an important role
give 4 examples of inorganic compounds
water, molecular oxygen, carbon dioxide and many salts , acids and bases
define organic compound
always contain carbon and hydrogen and typically are structurally complex
give 3 examples of organic compounds
polysaccharides, proteins, nucleic acids
name 8 characteristics of water
- one of the most abundant and important compounds
- facilitates the passage of nutrients into the cell
- medium for most chemical reactions inside the cell
- neutral charge
- polar molecule
- can form hydrogen bonds with nearby water molecules
- boils at 100 degrees celsius
- can be a liquid or solid
an acid can be defines as a (and give an ex.)
proton donor; ex: HCl
pH of an acid
less that 7
a base can be defined as a (and give example)
proton acceptor; ex: NaOH
pH of a base
greater than 7
neutral pH
7
3 functions of carbohydrates
- building block of DNA
- synthesis of amino acids and fats
- food reserves
3 elements that make up a carbohydrate
carbon, hydrogen, oxygen
ratio of hydrogen to oxygen in carbohydrates
2 : 1
name 3 examples of carbohydrates (with formulas)
- glucose (C6 H12 O6)
- ribose (C5 H10 O5)
- sucrose (C12 H22 O11)
what is a monosaccharide
a simple sugar
2 ex of monosaccharides
deoxyribose and glucose
what is a disaccharide
formed when 2 monosaccharides bond in a dehydration synthesis reaction
give 2 ex of disaccharides
disaccharide sucrose and disaccharide lactose
what is a polysaccharide
consists of tens or hundreds of monosaccharides joined through dehydration synthesis
give four examples of polysaccharides
gylcogen, cellulose, chitin, starch
name 3 elements that compose lipids
carbon hydrogen and oxygen
do lipids have a 2:1 ratio for hydrogen and oxygen
no
give 2 functions of lipids
- provide structure in membrane and in some cell walls
2. function in energy storage
give 2 lipid ex
fats and triglycerides
the building blocks of simple lipids are ___ and _____
glycerol and fatty acids
name the 4 elements that compose proteins
C, H, N, O and sometimes S
name the 4 functions of proteins
1 speed up biochemical reactions
- transport certain chemicals in and out of cell
- part of cell structures such as wall and membrane
- regulatory functions
name the building block of proteins
amino acids
how many amino acids occur naturally in proteins
20
what type of bond is found between amino acids in a protein
peptide bonds
in terms of proteins: the primary structure is a unique sequence in which the _____ are linked together
amino acids
in terms of proteins: the secondary structure is the repetitious…
twisting or folding of the polypeptide chain
in terms of proteins: the tertiary structure refers to the overall ________ of the polypeptide chain
3-D structure
in terms of proteins: the quaternary structure consists of 2..
or more individual polypeptide chains
define denaturation of proteins
when a protein unravels and loses its characteristic shape
name 3 ways proteins can be denatured
temp, pH, salt concentration
2 ex of nucleic acids
DNA and RNA
name the building blocks of nucleic acids
nucleotides
name the 3 components of nucleotides
- nitrogen-containing base
- pentose sugar
- phosphate group
name the 5 nitrogenous bases
thymine, adenine, guanine, cytosine, uracil
the 5 carbon sugar found in DNA is
deoxyribose
the 5 carbon sugar found in RNA is
ribose
