Upgrade to remove ads
Only $35.99/year

Chapter 2

Terms in this set (45)

atom
the smallest chemical unit of matter
element
matter composed of one kind of atom
molecule
when two or more atoms combine chemically (same or different)
-O2, CH4
compounds
molecules made up of atoms of two or more elements (different)
-CH4
atomic number
the number of protons of a particular element
-DALTONS
atomic mass (wt)
protons + neutrons + electrons
mass number
protons + neutrons
isotopes
atoms of a particular element that contain different number of neutrons
ion
-a charged atom produced when an atom gains or loses one or more electrons
cation
positively charged ion
anion
negatively charged ion
major chemical elements of life
C, H, N, O, P, S
chemical bonds
-major chemical elements bond in different ways to form various molecules of life
ionic bond
result from the attraction between ions that have opposite charges
covalent bonds
strong bonds which share PAIRS of electrons
-polarity caused by electronegativity
polar covalent bond
unequal sharing of electrons
nonpolar covalent bond
equal sharing of electrons
electronegativity
measure of the tendency of an atom to attract a bonding pair of electrons.
Hydrogen bonds
slight negative attracts slight positive
-weak bonds
metabolism
sum of all the reactions in the body
chemical reactions
-typically involve the use of energy to form chemical bonds and the release of energy as chemical bonds are broken
catabolism
breakdown of substances with the release of energy (exergonic)
anabolism
synthesis of substances with energy used to create bonds (endergonic)
acid
a hydrogen ion (H+) or proton donor
base
a proton acceptor or a hydroxyl ion (OH-) donor
organic chemistry
the study of compounds that contain carbon
biochemistry
a branch of organic chemistry that studies chemical reactions that occur in living systems
major classes of large, complex biochemical molecules
1) carbohydrates
2) lipids
3) proteins
4) nucleic acids largest
carbohydrates
-serve as main source of energy for most living things
-glycogen: storage form of energy in animals/starch in plants
-monosaccharide
-disaccharide
dehydration synthesis
two monosaccharides RELEASE one water molecule to form dehydration synthesis
-glucose and frucrose release H20 to create sucrose
isomer
same atoms, different structure
-glucose (C6H12O6) vs. fructose (C6H12O6)
proteins
-composed of building blocks called amino acids
-peptide bonds
-50 or more amino acids
amino acids
have at least one amino (-NH2) group and one acidic carboxyl (-COOH) group
-total of 20 amino acids
peptide bonds
covalent bond that links and amino acid of one amino acid to carboxyl group of another
-dipeptide: two amino acids linked together
the structure of proteins
primary, secondary, tertiary, and quaternary
primary structure
consists of the specific amino acids in a polypeptide chain
secondary structure
consists of the folding or coiling of amino acid chains into a particular pattern
-presence of Hydrogen bond
tertiary structure
folding of the protein into globular shapes or fibrous threadlike strands
quaternary structure
the association of several tertiary-structured polypeptide chains
-globular protein subunit, heme unit
ex) hemoglobin, keratin fiber
structural proteins
contribulte to the three-dimensional structure of cells, cell parts, and membranes
enzymes
protein catalysts-substances that control the rate of chemical reactions in cells
nucleotides
join to form nucleic acids
-building blocks
-contain: a nitrogenous base, a five-carbon sugar, one or more phosphate groups
no phosphate group=nucleoside
-ex) adenine, ribose, and phosphate=> three phosphate groups create ATP
nucleic acids
functions:
1) storage of energy in high-energy bonds
2) store information that directs protein synthesis
3) information can be transferred from parent to progeny (they make up the genes)
DNA
-double helix
-deoxyribose sugar
-thymine
cytosine<-->guanine; three-hydrogen bond
adenine<-->thymine; two-hydrogen bond
-phosphoric acid
RNA
-single stranded helix
-ribose sugar
-uracil
-phosphoric acid
Students also viewed