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50 terms

grace bio test 1

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A nucleotide is composed of a(n) _____.
phosphate group, a nitrogen-containing base, and a five-carbon sugar
The two strands of a DNA double helix are held together by _____ that form between pairs of nitrogenous bases.
hydrogen bonds
Which of the following statements about nucleotide structure is false?
a.The nitrogenous base is bonded to the sugar
b.The sugar is bonded to the phosphate group
c.The phosphate group is bonded to the nitrogenous base
d.The sugar can be either ribose or deoxyribose.
The phosphate group is bonded to the nitrogenous base
Which linkage forms the backbone of a nucleic acid?
A sugar-phosphate linkage
Which level(s) of protein structure may be stabilized by covalent bonds?
The primary structure of a protein is the specific linear sequence of amino acids forming the protein. The amino acids are joined by covalent peptide bonds. Tertiary structure, producing the unique structure of a protein, is stabilized by interactions among the R groups on each amino acid in the protein. Tertiary structure may be stabilized by covalent bonds, called disulfide bridges, that form between the sulfhydryl groups (SH) of two cysteine monomers
What is the function of a chaperonin?
Chaperonins are protein molecules that assist in the proper folding of other proteins by creating a hydrophyllic environment for the folding of the polypeptide.
Components of nucleotides are, and how are they connected?
a nucleotide monomer includes a nitrogenous base, a sugar, and a phosphate group. The phosphate group is bonded to the Sugar and the sugar to the nitrogenous base.
What are purines
Purines - a family of nitrogenous bases that describe bases that are larger than pyrimidines, with a six-membered ring fused to a five-membered ring. Examples are: Adenine
9. What are pyrimidines
Pyrimidines - a family of nitrogenous bases that describe bases that are smaller than purines, with a six-membered ring of carbon and nitrogen atoms. Examples are: Thymine, Cytosine, Uracil
10. Which term includes all others in the list?

a. Monosaccharide
b. Carbohydrate
c. Disaccharide
d. Starch
e. Polysaccharide
B. carbohydrates
The molecular formula for glucose is C6H12O6. What would be the molecular formula for a polymer made by linking ten glucose molecules together by dehydration reactions?
C60H102O51
Which of the following statements concerning unsaturated fats is true?

a. they are more common in animals than plants
b. they have double bonds in the carbon chains of their fatty acids
c. They generally solidify at room temperature
d. They contain more hydrogen than saturated fats having the same number of carbon atoms
e. they have fewer fatty acid molecules per fat molecule
b
The structural level of a protein least affected by a disruption in hydrogen bonding is the
primary level
Enzymes that break down DNA catalyze the hydrolysis of the covalent bonds that join nucleotides together. What would happen to DNA molecules treated with these enzymes?
the phosphodiester linkages between deoxyribose sugars would be broken
Why does a denatured protein no longer function normally?
the function of a protein is a consequence of its specific shape, which is lost when a protein become denatured
the secondary structure of proteins are constructed via ___________bonds between _________.
hydrogen bonds between atoms of the polypeptide backbones. Leads to beta pleated sheets and alpha helix.
the tertiary structure of proteins are constructed via ___________ bonds between _________.
tertiary structure results from interactions between sidechains (R groups) of various amino acids. Can occur due to hydrophobic ineractions which allow aminio acids with hydrophobic R groups end up in a cluster in the core of the protein to avoid contact w/ water.
Which molecule is not a carbohydrate?

a. starch
b. lipid
c. glycogen
d. cellulose
b. lipid
What is a Peptidoglycan?
polysaccharide found only in bacteria.
Which complex carbohydrate contains only a-1,4-glycosidic linkages?
amylose
What are attached to the central carbon atom in an amino acid?
The central carbon atom in an amino acid is bonded to an amino functional group, a carboxyl functional group, a side chain, and hydrogen.
Which part of an amino acid is always acidic and why?
The carboxyl group (COOH) contains two oxygen atoms that tend to pull electrons away from the hydrogen atom, so this group tends to lose a proton and is acidic.
Proteins are polymers of _____.
amino acids
What type of bond joins the monomers in a protein's primary structure?
covalent peptide bonds
Describe the structures of DNA and RNA as well as the difference between the two.
DNA and RNA have similar structures: a pentose sugar with a nitrogenous base and a phosphate group. DNA and RNA differ in the type of pentose sugar each possesses (DNA has deoxyribose; RNA has ribose) and in one base (DNA has thymine; RNA has uracil).
The two strands of a DNA double helix are held together by _____ that form between pairs of nitrogenous bases
hydrogen bonds
Define the quarternary structure of proteins and give two examples.
overall protein strucutre that results from the aggregation of these polypeptide subunits

ie) collagen, hemoglobin
Define: Sickle Cell Disease
inherited blood disorder cause by just ONE amino acid change in B hemoglobin.

reults from a substitution of one amino acid (valine) for the normal one (glutamic acid) at a particular position in the primary structure of hemoglobin, changing the overall shape of red blood cells which may clot small vessles
Denaturation of a protein leads to ______________.
Loss of shape --> loss of function
There are _____ different amino acids
20
How do aminoi acids form poylmers?
when 2 aminio acids are positioned so that teh carboxyl group is adjacent to eh amino group of the other, they become joined by a dehydration reaction.
Dehydration reaction results in ____________
removal of a water molecule
Isomers are _______________
same chemical formula, but different structures
structural isomers are ___________
type of an isomer,

different chemical groups of one or more carbons.
steroisomers are ____________
type of an isomer

different spatial arrangements of chemical groups around one or more carbons
Enantimorphs are ______________.
type of an isomer

mirror image of a steroisomer
disaccharides are linked via ________________.
glycocidic linkages
Glycocidic linkages are ___________
covalent bonds formed via dehydration reactions
Two examples of storage polysaccharides
1) starch - plants
2) glycogen - animals
What is cellulose?
Fiber found in plants (cell wall mostly composed of cellulose).

Very few animals possess the enzymes to break down cellulose with exception of cows and termites

cellulose microfibrils in which linear cellulose molecules are stored. Linear cellulose molecules interact via hydrogen bonds
Cellulose microfibrils store ______________ molecules that interact via _______________.
cellulose microfibrils in which linear cellulose molecules are stored. Linear cellulose molecules interact via hydrogen bonds
Difference between chitin and cellulose
Chitin has a nitrogen-containing appendage on the glocose monomer instead of an OH
Chitin is ____________
importatnt structural polysaccharide used by arthropods to build their exoskeletons.
Define disulfide bridges and how they are formed
Disulfide bridges form in teh tertiary structure of proteins. They form where two amino acids with sulfhydrul groups on their side chains are brough close together by the folding of the protein.

The sulfur of one cysteine bonds ot the sulfur of the second.
Define gene
Unit of inheritance tha tconsist of DNA.

Genes program the aminoi acid sequence of a polypeptide.
Common features between prokaryotic adn eukaryotic cells
all bounded by plasma membrane
all have cytosol
all contain chromosomes which carry genes in the form of DNA
All cells have ribosomes
Proteins are made in ____________
ribosomes
In a eukaryotic cell, most of the DNA is in _______________
an organelle called the nucleus which is bounded by a double membrane
location of DNA in prokaryotic cell
DNA is concentrated in a region tha tis no membrane-enclosed called a nucleoid.
plasma membrane functions as a _________________
selective barrier that allows sufficient passage of oxygen, nutrients and wastes to service the entire cell.