Exam 2 Review Part II Flashcards
(25 cards)
What molecules are responsible for the formation of the spliceosome complex?
Small nuclear RNAs
True or False
Chloroplasts and mitochondria use their own unique genetic code.
True
Name the 3 tRNA binding sites formed by a ribosome for translation of a protein
P-peptidyl
A - aminoacyl
E - Exit
How many possible stop codons are there in eukaryotic mRNA?
3:
UAG
UAA
UGA
During translation, the role of enzyme peptidyl transferase is
A. Transfer of a phosphate group
B. Amino acid activation
C. Peptide bond formation between adjacent amino acids
D. Binding of ribosome subunits to mRNA
C. Peptide bond formation between adjacent amino acids
As part of an early experiment on the secretory system, an in vitro translation system consisting only of mRNA and ribosomes resulted in proteins that were larger than the identical protein when translated in a cell. Why did this happen?
Signal sequence cleavage requires ER entry and the action of ER-resident proteins
Mitochondrial proteins transcribed from the nuclear genome are:
Synthesized by free cytosolic ribosomes and brought to the mitochondrial membrane in an unfolded form by chaperone proteins such as Hsp70
GLUT (glucose transporters) proteins transport glucose from the blood to cells. Which of the following statements about them are FALSE?
A. GLUT proteins are an example of active transport
B. GLUT proteins require ATP to transport glucose across the cell membrane
C. Binding of glucose to the transporter protein leads to a conformation change and the transport of glucose to the other side of the membrane.
D. GLUT proteins can only transport proteins from the outside of the cell to the cytoplasm
E. A, B and C
F. A, C and D
G. A, B and D
F. B, C and D
G. A, B and D
A. GLUT proteins are an example of active transport
B. GLUT proteins require ATP to transport glucose across the cell membrane
D. GLUT proteins can only transport proteins from the outside of the cell to the cytoplasm
Nuclear export of proteins from the cytoplasm occurs through _______ using the nuclear cargo protein _______.
C. nuclear pore complexes; exportin
What are the important ER-resident enzymes that modify proteins in the secretory pathway?
Oligosaccharyl transferase and Protein disulfide isomerase
Briefly describe allosteric regulation of an enzyme
Allosteric regulation refers to the process for modulating the activity of a protein by the binding of a ligand to a site topographically distinct from the site of the protein
List these molecules in order from most to least permeable through a lipid bilayer: peptide, carbon dioxide, calcium ion, glucose
Carbon dioxide, glucose, calcium ion, peptide
Which of the following statements is true regarding regulation of glycolysis
A. Hexokinase regulates glycolysis by degrading glucose-6-phosphate
B. Low levels of ATP inhibit phosphofructokinase-1 because ATP preferentially binds to the allosteric inhibition site.
C. Inhibition of glucose-6-phosphate by hexokinase is an example of feedback inhibition
D. None of these statements are correct.
C. Inhibition of glucose-6-phosphate by hexokinase is an example of feedback inhibition
What source of energy is needed for unidirectional translocation of a protein into the mitochondrial matrix?
ATP
Which of the following statements regarding the electron transport chain is TRUE?
A. Cytochrome c transports electrons from complex I and complex II to ATP synthase
B. Cytochrome oxidase (complex IV) accepts electrons from cytochrome c
C. Only complex II (succinate-CoQ reductase) pumps protons directly across the inner mitochondrial membrane
D. Coenzyme Q resides in the mitochondrial matrix
B. Cytochrome oxidase (complex IV) accepts electrons from cytochrome c
The citric acid cycle consists of the oxidation of ________ to produce _____,_____, and _____.
acetyl CoA; NADH, FADH2, and ATP
The energy required to drive the transport of small molecules in and out of the mitochondrial matrix is provided by:
The electrochemical gradient
What source of energy is needed for unidirectional translocation across the membrane during cotranslational translocation into the endoplasmic reticulum?
GTP hydrolysis
In terms of its role in the generation of metabolic energy, the thylakoid membrane of chloroplasts is equivalent to the ___________ of mitochondria.
A. Outer membrane
B. Inner membrane space
C. Matrix
D. None of the above
D. None of the above
True or False
GTP can easily be converted to ATP in the cell, meaning that GTP produced during the citric acid cycle can feed directly into powering ATP synthase
True
Which statements are correct in regards to the formation of chloroplasts?
A. Chloroplasts contain special light-harvesting pigments in their thylakoid membranes that are responsible for the light reactions of photosynthesis
B. All plastids, including chloroplasts, develop from proplastids that are capable of converting from one plastid type to another
C. The thylakoid membrane is equivalent to the outer mitochondrial membrane in that it is the sight of ATP synthesis
D. Chromoplasts are specialized plastids that contain different pigment proteins than chlorophyll, but are also able to participate in photosynthesis
E. A and B
F. A and C
G. A and D
F. A and B
A. Chloroplasts contain special light-harvesting pigments in their thylakoid membranes that are responsible for the light reactions of photosynthesis
B. All plastids, including chloroplasts, develop from proplastids that are capable of converting from one plastid type to another
The inner mitochondrial membrane contains proteins that
Synthesize ATP, pump protons, and transport pyruvate
Chloroplasts are similar to mitochondria in that both
Have a porous outer membrane
The inner compartment of mitochondria is called the
Matrix
