MICR 3033 Exam 2 Questions with
Complete Solutions
Endoglucanases and cellobiohydrolases have the same catalytic center but have a
variant configuration of the binding site. Identify, which of the following is TRUE? -
Answer-Because the catalytic site is identical but the binding site different both enzymes
can interact with the substrate in different ways thus producing different catalytic
products.
Two molecules are similar but not identical in structure and affect enzyme activity
differently. Identify the statements that are NOT TRUE?
A
if both molecules are catalyzed by the same enzyme at different Vmax and Km they are
both substrates.
B
if one molecule is catalyzed and the other not but interferes with Vmax and Km the
second molecule is an inhibitor.
C
the substrate that has the lowest Km is likely to have a better fit with the binding site of
the enzyme.
D
the substrate that has a higher Vmax must have a lower Km. - Answer-D
the substrate that has a higher Vmax must have a lower Km.
Protein kinases phosphorylate target enzymes and as a result enzymes become
activated or inactivated. Which of the following statement is NOT TRUE?
A
phosphorylated enzymes may behave like competitive inhibitors.
B
the presence of a phosphate group may act as a non-competitive inhibitor/activator. No
change in Km but significant change in Vmax.
C
the presence of a phosphate group may induce a conformational change that modifies
the affinity and catalytic ability of a target enzyme.
D
the presence of a phosphate group tags the enzyme allowing interactions with other
enzymes. - Answer-D
the presence of a phosphate group tags the enzyme allowing interactions with other
enzymes.
, Which characteristic of a phospholipid contributes to the fluidity of the membrane? -
Answer-double bonds in the fatty acid tail
Which transport mechanism can bring whole cells into a cell? - Answer-phagocytosis.
What happens to the membrane of a vesicle after exocytosis? - Answer-It fuses with
and becomes part of the plasma membrane.
Thinking on the molecules Na+, O2, H2O, K+ and CO2, order them based on their
ability to permeate the membrane - from very fast to very slow. - Answer-fast - O2 -
CO2 -H2O -K+ -Na+ -slow
Phospholipids make a fluid liquid, meaning that molecules move within the membrane
structure without the input of energy. Which of the following phospholipid movements
require the input of energy? - Answer-phospholipid flipping (movement from one layer to
another).
What configures a transmembrane domain? - Answer-a stretch of amino acids
intercalated by non-polar and polar amino acids where all non-polar amino acids face
the membrane and polar amino acids produce a hydrophilic lumen.
Which of the following is all ACTIVE transport - Answer-ATP and light driven pumps as
well as coupled transport.
What is the difference between a MICELLE and a LIPOSOME. Identify ALL TRUE
statements - Answer-A
Liposomes are double layered membranes (made with phospholipids) which separate
two aqueous environments
B
Micelles are single layered lipids (not phospholipids) that form spontaneously in an
aqueous environment
C
Phospholipids are powerful drug delivery systems used by PHARMA
D
Micelles are powerful bullets that form when we cook pasta at home from scratch
In a typical eukaryotic cell, how much of the intracellular aqueous space is roughly
confined into compartments? - Answer-50%
Which subatomic particle is displaced when two or more atoms combine make a
molecule? - Answer-Electrons
What type of bond is formed when atoms share electrons? - Answer-Covalent
What determines the number of covalent bonds an atom can create? - Answer-the
excess or shortage of electrons in its outermost electron shell.
Complete Solutions
Endoglucanases and cellobiohydrolases have the same catalytic center but have a
variant configuration of the binding site. Identify, which of the following is TRUE? -
Answer-Because the catalytic site is identical but the binding site different both enzymes
can interact with the substrate in different ways thus producing different catalytic
products.
Two molecules are similar but not identical in structure and affect enzyme activity
differently. Identify the statements that are NOT TRUE?
A
if both molecules are catalyzed by the same enzyme at different Vmax and Km they are
both substrates.
B
if one molecule is catalyzed and the other not but interferes with Vmax and Km the
second molecule is an inhibitor.
C
the substrate that has the lowest Km is likely to have a better fit with the binding site of
the enzyme.
D
the substrate that has a higher Vmax must have a lower Km. - Answer-D
the substrate that has a higher Vmax must have a lower Km.
Protein kinases phosphorylate target enzymes and as a result enzymes become
activated or inactivated. Which of the following statement is NOT TRUE?
A
phosphorylated enzymes may behave like competitive inhibitors.
B
the presence of a phosphate group may act as a non-competitive inhibitor/activator. No
change in Km but significant change in Vmax.
C
the presence of a phosphate group may induce a conformational change that modifies
the affinity and catalytic ability of a target enzyme.
D
the presence of a phosphate group tags the enzyme allowing interactions with other
enzymes. - Answer-D
the presence of a phosphate group tags the enzyme allowing interactions with other
enzymes.
, Which characteristic of a phospholipid contributes to the fluidity of the membrane? -
Answer-double bonds in the fatty acid tail
Which transport mechanism can bring whole cells into a cell? - Answer-phagocytosis.
What happens to the membrane of a vesicle after exocytosis? - Answer-It fuses with
and becomes part of the plasma membrane.
Thinking on the molecules Na+, O2, H2O, K+ and CO2, order them based on their
ability to permeate the membrane - from very fast to very slow. - Answer-fast - O2 -
CO2 -H2O -K+ -Na+ -slow
Phospholipids make a fluid liquid, meaning that molecules move within the membrane
structure without the input of energy. Which of the following phospholipid movements
require the input of energy? - Answer-phospholipid flipping (movement from one layer to
another).
What configures a transmembrane domain? - Answer-a stretch of amino acids
intercalated by non-polar and polar amino acids where all non-polar amino acids face
the membrane and polar amino acids produce a hydrophilic lumen.
Which of the following is all ACTIVE transport - Answer-ATP and light driven pumps as
well as coupled transport.
What is the difference between a MICELLE and a LIPOSOME. Identify ALL TRUE
statements - Answer-A
Liposomes are double layered membranes (made with phospholipids) which separate
two aqueous environments
B
Micelles are single layered lipids (not phospholipids) that form spontaneously in an
aqueous environment
C
Phospholipids are powerful drug delivery systems used by PHARMA
D
Micelles are powerful bullets that form when we cook pasta at home from scratch
In a typical eukaryotic cell, how much of the intracellular aqueous space is roughly
confined into compartments? - Answer-50%
Which subatomic particle is displaced when two or more atoms combine make a
molecule? - Answer-Electrons
What type of bond is formed when atoms share electrons? - Answer-Covalent
What determines the number of covalent bonds an atom can create? - Answer-the
excess or shortage of electrons in its outermost electron shell.
