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77 terms

bio101

organic molecules
STUDY
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Which polymers are composed of amino acids?
proteins
What is attached to the central carbon atom in an amino acid?
an amino functional group, a carboxyl functional group, a side chain ("R group")
Which part of an amino acid is always acidic?
carboxyl functional group
Which monomers make up RNA?
nucleotides
What happens during the formation of polypeptides from amino acids?
a bond forms between the carboxyl functional group of one amino acid and the amino functional group of the other amino acid
True or false? Enzymes in the digestive tract catalyze hydrolysis reactions.
true
Which molecule is not a carbohydrate? cellulose, glycogen, lipid, starch
lipid
True or false? Monosaccharides can be classified according to the spatial arrangement of their atoms.
true
True or false? Peptidoglycan is a polysaccharide found only in bacteria.
true
Which complex carbohydrate contains only a-1,4-glycosidic linkages?
amylose
What is the function of cellulose?
it is the structural component of plant cell walls
Glycogen is _____.
a polysaccharide found in animals
glucose + glucose —> _____ by _____.
maltose + water ... dehydration synthesis
Name a source of lactose.
milk
_____ is the most abundant organic compound on Earth.
cellulose
All carbohydrates have this general formula .
Cx(H2O)x
A simple sugar is composed of equal parts carbon and water, which gave rise to the general name of any sugar as a _____.
carbohydrate
A _____ can not be hydrolyzed any further.
monosaccharide
Lactose, the sugar in milk, is a _____, because it can be split into two monsaccharides.
disaccharide
A carbohydrate that yields many many monosccharides when it is hydrolyzed is a _____.
polysaccharide
Which of these is not a lipid? wax, steroids, phosphlipids, RNA, cholesterol
RNA
Phospholipids are composed of a _____, a _____, and _____.
phosphate group, a glycerol, and fatty acids
A function of cholesterol that does not harm health is its role _____.
as a component of animal cell membranes
Defensive proteins are manufactured by the _____ system.
immune
_____ structure is the sequence of amino acids in a protein.
Primary
_____ structure describes the alpha-helices and beta-sheets that are formed by hydrogen bonding between backbone atoms located near each other in the polypeptide chain.
secondary
_____ structure is achieved when a protein folds into a compact, three-dimensional shape stabilized by interactions between side-chain "R-groups" of amino acids.
tertiary
_____ structure is the result of 2 or more protein subunits assembling to form a larger, biologically active protein complex.
quartermary
If a strand of DNA has the nitrogen base sequence 5'-ATTTGC-3', what will be the sequence of the matching strand?
3'-TAAACG-5'
If a DNA double helix is 100 nucleotide pairs long and contains 25 adenine bases, how many guanine bases does it contain?
75.100 nucleotide pairs are a total of 200 nucleotides. Because of base pairing, if there are 25 adenine there must also be 25 thymine. This leaves 200-50 = 150 nucleotides to be divided evenly between guanine and cytosine.
The two strands of a DNA double helix are held together by _____ that form between pairs of nitrogenous bases.
hydrogen
A nucleotide is composed of a(n) _____.
phosphate group, a nitrogen-containing base, and a five-carbon sugar
True or false? Guanine and uracil are examples of nitrogenous bases.
true
Which linkage forms the backbone of a nucleic acid?
a sugar-phosphate linkage
What is the complementary DNA sequence to 5' ATGCATGTCA 3'?
5' TGACATGCAT 3'
Which of these are used exclusively in DNA; ribose, guanine, uracil, thymine, adenine, cytosine, phosphate group, deoxyribose,
deoxyribose and thymine
Which of these are used exclusively in RNA; ribose, guanine, uracil, thymine, adenine, cytosine, phosphate group, deoxyribose,
ribose and uracil
Which of these are used in both DNA and RNA; ribose, guanine, uracil, thymine, adenine, cytosine, phosphate group, deoxyribose,
phosphate group, adenine, guanine, and cytosine
A dehydration reaction (or condensation reaction) is the process in which _____.
water molecules are produced as a polymer is formed from monomers
The four main categories of macromolecules present in living systems are _____.
proteins, nucleic acids, carbohydrates, and lipids
Sucrose is formed when glucose is joined to fructose by a(n) _____.
glycosidic linkage
Plant cell walls consist mainly of _____.
cellulose
The characteristic that all lipids have in common is that _____.
none of them dissolves in water
True or false? Almost all the covalent bonds in lipids are nonpolar, causing their solubility in water to be extremely low. Lipids are hydrophobic substances.
true
Palm oil and coconut oil are more like animal fats than are other plant oils. Because they ____ than other plant oils, they may contribute to cardiovascular disease.
contain fewer double bonds
Some regions of a polypeptide may coil or fold back on themselves. This is called _____, and the coils or folds are held in place by _____.
secondary structure ... hydrogen bonds
A hydrophobic amino acid R group (side group) would be found where in a protein?
on the inside of the folded chain, away from water
The flow of genetic information in a cell goes from _____.
DNA ----> RNA ----> protein
The building blocks or monomers of nucleic acid molecules are called _____.
nucleotides
Define the term polymer.
a long molecule consisting of many similar or identical building blocks linked by covalent bonds
Define the term monomer.
the repeating units that serve as the building blocks of a polymer
Define the term glycosidic linkage.
a covalent bond formed between 2 monsaccharides by a dehydration reaction
Define the term saturated fat.
no double bonds form between carbon atoms, H atoms are tightly bonded to the carbon chain, form solid fats
Define the term unsaturated fat.
has one or more double bonds, formed by removal of H atoms from carbon skeletons, forming a kink in the hydrocarbon chain, wherever a cis double bond occurs, form liquid fats
What is the principal energy storage molecules of plants and animals?
carbohydrates
What is a protein composed of?
1 or more polypeptides, each folded and coiled into a specific 3-dimensional pattern
What is a polypeptide?
polymers of amino acids
Define the term peptide bond.
2 amino acids- 1 positioned adjacent to the amino group of the other, joined by dehydration synthesis, removes a water molecule, resulting in a covalent bond
What are the four major components of an amino acid?
amino group, side chain "R" group, carboxyl group, alpha carbon
What is the function of the "R" group side chain in an amino acid?
determines the unique characteristics of a particular amino acid, effects the functional role in a polypeptide
What is the function of the amino group in an amino acid?
acts as a base, can pick up H+ from the surrounding solN (water in living organisms), ionized with a charge of 1+ under cellular conditions
What is the function of the carboxyl group in an amino acid?
has acidic properties (source of hydrogen ions) due to the covalent bond between O2 and H's high polarity
What is the function of the alpha carbon in an amino acid?
where different substituents attach to each different amino acid
What determines protein conformation?
determined by the set of amino acids assigned to it
Why is protein conformation important?
it specializes the protein to become either a transport protein, enzyme, etc...
How is the primary structure of a protein determined?
DNA
What are the 2 types of secondary protein structure?
beta- pleated sheet alpha- helix
How do weak interactions contribute to tertiary protein structure?
Van der Waals interactions hold nonpolar amino acid side chains together
How do disulfide bridges contribute to tertiary protein structure?
the shape is reinforced further by covalent bonds, form where 2 cytosine monomers, amino acids, with a sulfhydryl group (-SH) on their side chains are brought close together by the folding of the protein
What are 4 conditions under which proteins may be denatured.
pH, salinity, temperature, and chemical concentration
What are the 4 major components of a nucleotide?
purine, pyrimidine, sugars, phosphate group
How are the 4 major components of a nucleotide linked to form a nucleic acid?
sugar pentose connects to the nitrogenous base, forming a nucleoside. they are joined by phosphodiester linkages between the phosphate of one nucleotide and the sugar of the next
Define the term pyrimidine.
six-membered ring of carbon and nitrogen atoms (cytosine, thymine, uracil)
Define the term purine.
six-membered ring fused to a five-membered ring (adenine, guanine)
What is a ribose molecule?
a sugar connected to a nitrogenous base
What is a deoxyribose molecule?
a nitrogenous base connected to a sugar, lacks an oxygen atom on the second carbon in the ring
Briefly describe the three-dimensional structure of DNA.
double stranded, sugar-phosphate backbone of the antiparallel polynucleotide strands on the outside of the helix. nitrogenous bases bind though H bonds (AT-GC). DNA molecules form a double helix (a spiraling ladder)