BIO206H5 Lecture Notes - Lecture 4: Alpha Helix, Protein Structure, Beta Sheet
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Second messengers play an important role in cellcommunication.
Which of the following best describes their role?
None | ||
integrate, amplify and distribute messages throughout thecell | ||
Release messages to other cells? | ||
Receive information at the cell surface |
What is true of disulfide bonds?
a. | They often occur in the cytosol | |
b. | They are a noncovalent bond | |
c. | They are formed enzymatically in the ER | |
d. | They act as reducing agents | |
e. | they increase protein flexibility |
Which of the following is NOT an example of a cell communicationmolecule?
nucleases | ||
nitric oxide | ||
hormones | ||
kinases |
What is true of binding pockets?
a. | They only occur in the membrane | |
b. | They occur in unfolded proteins | |
c. | They contain electrostatic interactions | |
d. | They contain variable amino acids | |
e. |
What is true of cell signaling?
a. | Extracellular signals transduced by rectors always alter cellbehavior very quickly | |
b. | Some cells require cell signals just to survive | |
c. | Cell signals can be interpreted differently by differentcells | |
d. | B and C only | |
e. | All of the above (A, B and C) |
Histone tails can be modified to change the shape and"tightness" of the nucleosomes. Acetylated histones result in whicheffect?
Open DNA | ||
increased transcription | ||
closed DNA | ||
decreased transcription | ||
1+2 | ||
1+4 | ||
3+4 | ||
2+3 |
Shifting the two bound tRNA from the A and P sites to the E andP sites of the ribosome involves:
a. | The movement of the small ribosome subunit down the mRNAchain | |
b. | The degradation of the A site on ribosome | |
c. | The synthesis of the E site on the ribosome | |
d. | The movement of the large subunit relative to the smallsubunit | |
e. | All of the above |
Intracellular signaling pathways are awesome! What is the onething they can NOT do?
a. | relay the signal, to spread it through the cell | |
b. | nothing, they can communicate any cellular need | |
c. | distribute the signal to more than one effector protein | |
d. | integrate the signal from more than one cellular pathway | |
e. | Amplify the signal received, making the signal stronger |
Specificity of protein/protein and protein/DNA binding isdetermined by what?
Non-covalent bonds | ||
Hydrophobic interactions | ||
Covalent bonds | ||
shape of the binding site | ||
all of the above | ||
none of the above | ||
1,2,3 | ||
1,2,4 | ||
1,3,4 |
The coiling structure of the DNA into chromosomes is achieved bywhat?
alpha helix | ||
beta pleated sheets | ||
chaperone proteins | ||
DNA/Protein complexing |
Which regions (s) of the DNA are found in the final protein?
a. | poly-A tail | |
b. | A and B | |
c. | Exons | |
d. | UTRs | |
e. | Introns |
Metabolic processes can be turned "on" and "off" by chemicalmodifcation.
Which chemical modification do we associate with changing theactivity of an enzyme in a transient/non-permanent manner?
Phosphorylation | ||
Ubiquitination | ||
Methylation | ||
Acetylation |
DNA hybridization involves attaching a florescent dye towhat?
a. | Antibody | |
b. | Nuclear stain | |
c. | Probe DNA | |
d. | tRNA | |
e. | rRNA |
Question 401 pts
Kinetic energy is the stored energy that can be used for motion.
True |
False |
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Question 411 pts
When an electron is transferred from one atom to another, and the two atoms are then electrically attracted to one another, a(n) ________________ bond is formed.
ionic |
kinetic |
covalent |
hydrogen |
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Question 421 pts
Changing the number of ____________ of an atom would change the chemical properties of the atom.
neutrons |
protons |
electrons |
electron shells |
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Question 431 pts
Forming molecules and breaking down molecules in biological organisms usually requires the use of _________ to help the reaction proceed faster.
oil |
heat |
enzymes |
blood |
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Question 441 pts
Organic molecules have a core composed of .
carbon |
nitrogen |
phosphorus |
hydrogen |
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Question 451 pts
The building blocks of carbohydrates are
polypeptides |
amino acids |
nucleotides |
monosaccharides |
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Question 461 pts
Water molecules crossing a membrane from high to low concentration is .
active transport |
cell fate |
facilitated diffusion |
osmosis |
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Question 471 pts
Choose the membrane molecule responsible for the passage of polar molecules and ions into and out of the cell.
phospholipids |
transmembrane channel proteins |
cell surface proteins |
carbohydrate chains |
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Question 481 pts
The simplest cells are .
prokaryotic |
animal cells |
eukaryotic |
cells of fungi |
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Question 491 pts
Which of the following membrane bound organelles are found inside bacterial cells:
nucleus |
organelles are not found in prokaryotic cells |
mitochondria |
chloroplasts |
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Question 501 pts
Which of the following is a specialized components of the cell, is associated with the rough endoplasmic reticulum, and is responsible for making proteins.
vacuoles |
ribosomes |
golgi complex |
nucleus |
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Question 511 pts
Proteins are sorted, modified, and packaged by the _____________ and later transported to the outside of the cell.
ribosomes |
golgi bodies (golgi apparatus) |
nucleus |
mitochondria |
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Question 521 pts
Dehydration synthesis is a process of linking two smaller subunits together to form a polymer. Which of the following statements below is true of dehydration synthesis?
Oxygen is consumed. |
A water molecule is removed from the molecules. |
A water molecule is added to the molecules |
Carbon dioxide is given off. |
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Question 531 pts
Proteins are made up of _________ held together by peptide bonds.
monomers |
monosaccharides |
polymers |
amino acids |
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Question 541 pts
Which of the following gives an amino acid its properties?
NH2 |
R Group or functional group |
COOH |
H |
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Question 551 pts
The final three-dimensional shape of a protein that includes the bonding of two or more polypeptide chains is call its _____ structure.
Tertiary |
Quaternary |
Secondary |
Primary |
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Question 561 pts
How do DNA and RNA differ?
all statements are differences between DNA and RNA. |
DNA is double stranded while RNA is single stranded. |
They have different sugars. |
Thymine is present in DNA but not in RNA. |
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Question 571 pts
Which of the following is a component of a DNA nucleotide?
phosphate |
a nitrogen containing base |
All are components of a nucleotide. |
5-carbon sugar |
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Question 581 pts
Cell membranes are made up of several different types of molecules. Select the membrane molecule below that is made up of a polar region and two non-polar fatty acid tails.
transmembrane proteins |
carbohydrate chains |
phospholipids |
cell surface proteins |
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Question 591 pts
Two organelles which are believed to have once been free-living bacterial cells are ____________ and ______________.
chloroplasts and mitochondria |
golgi apparatus and endoplasmic reticulum |
ribosomes and nucleolus |
peroxisomes and lysosomes |
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Question 601 pts
The is an extensive system of internal membranes responsible for producing carbohydrates and lipids.
smooth endoplasmic reticulum |
rough endoplasmic reticulum |
nucleolus |
mitochondria |