Exam 2 Review Flashcards
What is a gene?
a locus (region) of DNA that encodes a functional RNA or protein product, it is also the molecular unit for heredity
What is the molecular unit for heredity?
a gene (the smallest unit of measurement)
What is a polypeptide?
a chain of amino acids, proteins are made up of one or more polypeptide molecules
Amino acids are linked _____ in _____ bonds in order to form a polypeptide.
covalently, peptide
What are the subunits of proteins?
amino acids
What are the 5 main functions of nucleic acids?
heredity (store and transport information), cell control, energy storage, electron carriers, and signaling (i.e. DNA and RNA)
What is the central dogma of molecular biology?
DNA can be copied into DNA (replication). DNA codes for RNA, which codes for proteins. DNA is responsible for heredity (passing of traits onto offspring). It contains the instructions for building RNA and proteins, which make up the structure of the body and carry out most of its functions.
What is the coding of DNA to RNA called?
transcription
What is the coding of RNA to a protein called?
translation
What is the process of DNA creating more DNA?
DNA replication
What is a macromolecule?
a series of small subunits covalently bonded to form a larger molecule
What is a monomer?
one subunit (relatively small molecule)
What is a dimer?
two subunits
What is a trimer?
three subunits
What is a tetramer?
four subunits
What are the subunits of lipids?
fatty acids and glycerol
What are the subunits of carbohydrates?
monosaccharides
What are the subunits of nucleic acids?
nucleotides
What are isomers? Give an example.
molecules that have the same chemical formula, but a different arrangement of atoms in space (fructose and glucose)
Plants store energy as _____ while animals store energy as _____.
starch, glycogen
What is a disaccharide?
a sugar composed of two monosaccharides
What are the three types of lipids?
triglycerides, phospholipids, and steroids
What is polymerization?
a process of reacting monomer molecules together in a chemical reaction to form polymer chains or three-dimensional networks
Subunits of a macromolecule are joined together in _____ bonds.
covalent
What type of reaction is responsible for the polymerization of the four main types of subunits/molecules?
a condensation reaction (a reaction accompanied with the formation of a water molecule, water is lost), also known as a “dehydration reaction”
What type of covalent bond do amino acids form?
peptide
What type of covalent bond do fatty acids and glycerol form?
ester
What type of covalent bond do monosaccharides form?
glycosidic
What type of covalent bond do nucleotides form?
phosphodiester
Are lipids hydrophobic or hydrophilic?
hydrophobic (not soluble in water)
What are triglycerides responsible for?
energy storage
What are phospholipids responsible for?
membranes
What are steroids responsible for?
signaling (hormones) and membranes
What are triglycerides responsible for?
energy storage
What are the components of a triglyceride?
one glycerol and three fatty acids
Within a triglyceride, each carbon atom will form exactly _____ bonds with other atoms.
four
What is a glycerol molecule?
three carbons and three hydroxyl (OH-) groups
What is a fatty acid?
chain of carbons (CH2) with carboxyl (COOH-) at one end, and CH3 on the other
What is a carboxyl group?
COOH-
How many carbons exist between the carboxyl and CH3 in a fatty acid?
10-40
Fatty acids are amphipathic, which means _____.
the two ends of the molecule differ in chemical properties
The hydrophilic part of a fatty acid consists of the _____ group, which means that this part of the molecule is _____.
carboxyl, polar (because water is polar, too)
The hydrophobic part of a fatty acid consists of a _____ chain and a _____ molecule, which means that this part of the molecule is _____.
carbon/hydrogen chain, CH3, nonpolar (because water is polar)
What does “saturated” mean when it comes to fatty acids?
hydrogen occupies all available bond space
What does “unsaturated” mean when it comes to fatty acids?
hydrogen does not occupy all available bond space
What forms if two adjacent carbons are missing hydrogen atoms within a fatty acid?
a double bond
Saturated fats are “regular,” so they form _____.
tight crystals
Saturated fats have _____ melting points.
high
Unsaturated fats have _____ melting points.
low
What is a fatty acid “tail”?
string of carbons
Saturated fates have _____ bonded carbons because all of the bond space is occupied with hydrogen.
single
Unsaturated fats have _____ or _____ bonded carbons because not all of the bond space is occupied with hydrogen.
double, triple
Unsaturated fatty acids are usually in _____ form and have _____ tails.
liquid, short
Saturated fatty acids are usually in _____ form and have _____ tails.
solid, long
Amphipathic lipids form _____ in water.
micelles
What is a micelle?
a lipid molecule that arranges itself in a spherical form in an aqueous solution