Exam 1 Flashcards
which of the following is not true regarding living organisms ?
all organisms are capable of resurrection
Recall Pasteur’s experiment on spontaneous generation. If he had just warmed the nutrient-rich broth,rather than boiled it , what would have been the likely outcome of his experiment ? Cells would ____ ?
Have appeared in both flasks
A covalent chemical bond is one in which ?
Outer shell electrons of two atoms so as to satisfactorily fill their respective orbitals
How may electrons are involved in a single covalent bond ?
two
In a single molecule of water , two hydrogen atoms are bonded to a single oxygen atom by
polar covalent bonds
when the atoms involved in a covalent bond have the same electronegativity , what type of bond results?
a nonpolar covalent bond
the partial negative charge at one end of water molecule is attracted to the partial positive charge pf another water molecule. What is this attraction called ?
hydrogen bond
what component of amino acid structure varies among different amino acids ?
the components of the R-group
Which one of the following is NOT a component of each monomer used to make proteins ?
a phosphorus atom, P
you disrupt all hydrogen bonds in a protein . What level structure will be preserved ?
primary structure
Which type of interaction stabilizes the a-helix and the b-pleated sheet structures of proteins ?
hydrogen bonds
what type of interaction is directly responsible for the formation of secondary structure ?
hydrogen bonds between sections of the polypeptide backbone
the tertiary structure of a protein is the ?
unique shape of the fully folded polypeptide
Nucleic acids are polymers made up of which of the following monomers ?
nucleotides
An enzye has total of four active sites. When you denature the molecule and study its composition ,you find that each active site occurs on a different polypeptide. Which of the following hypotheses does this observation support ?
the protein has quaternary structure
what is the difference between a ribonucleotide and a deoxyribonucleotide ?
riobnucleotides have a hydroxyl group on the 2 carbon of their subunit
Which of the following uncludes all of the pyrimidines found in RNA and DNA ?
Cytosine , uracil & thymine
When nucleotides polymerize to form a nucleic acid ?
a covalent bond forms between the sugar of one nucleotide and the phosphate of a second
Which of the following descriptions best fits the class of molecules known as nucleotides ?
a base , a phosphate group and a sugar
The difference between the sugar in DNA and the sugar in RNA is that the sugar in DNA ?
contains one less oxygen atom
compare proteins to nucleic acids. Which of the following is TRUE ?
Both have primary and secondary structure
Adouble-stranded DNA molecule contains a total of 120 purines and 120 pyrimidines. DNA molecule could be composed of ?
120 thymine and 120 adenine molecules
Which of the following statements best summarizes the difference between DNA and RNA
DNA nucleotides contain a different sugar than RNA
Which of the following can vary among monosaccharides ?
the number of carbon atoms
