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Cell Bio
Final Exam
97
Biology
Undergraduate 4
05/05/2013

Additional Biology Flashcards

 


 

Cards

Term
A covalent bond is likely to be polar when...
Definition
One of the atoms sharing electrons is much more electronegative than the other atom.
Term
A group of molecular biologists is trying to synthesize a new artificial compound to mimic the effects of a known hornmone that influences sexual behavior. They have turned to you for advice. Which of the following compounds is most likely to mimic the effects of the hormone?
Definition
A compound with the same number of carbon atoms as the hormone.
Term
Which functional groups are always found in amino acids?
Definition
carboxyl and amino
Term
What best summarizes the relationship between dehydration reactions and hydrolysis?
Definition
dehydration reactions assemle polymers and hydrolysis reactions break down polymers.
Term
The label on a container of margarine lists "hydrogenated vegetable oil" as the major ingredient. What is the result of adding hydrogens to a vegetable oil?
Definition
The hydrogenated vegetable oil stays solid at room temperature.
Term
There are 20 different amino acids. What makes one amino acid different from another?
Definition
Different side chains (R groups) attached to the amino groups.
Term
What aspects of protein structure are stabilized or assisted by hydrogen bonds?
Definition
Secondary, tertiary, quaternary, but not primary structures.
Term
Which level of protein structure do the alpha helic and beta pleated sheet represent?
Definition
Secondary
Term
Which bonds are created during the formation of the primary structure of a protein?
Definition
peptide bonds
Term
Misfolding of polypeptides is a serious problem in cells. Which of the following diseases are associated with an accumulation of misfolded peptides?
Definition
Alzheimers and Parkinsons
Term
Normal hemoglobin is a tetramer, consisting of two molecules of beta hemoglobin and two molecules of alpha hemoglobin. In sickle-cell disease, as a result of a single amino acid change, the mutant hemoglobin tetramers associate with each other and assemle into large fibers. Based on this information alone, we can conclude that sickle-cell hemoglobin exhibits..
Definition
Altered primary structure and altered quaternary structure; the secondary and tertiary structures may or may not be altered.
Term
What is the term used for a protein molecule that assists in the proper folding of other proteins?
Definition
Chaperonin
Term

How do you describe the class of molecules known as nucleotides?

 

Definition
a nitrogenous base, a phosphate group, and a pentose sugar
Term
Large numbers of ribosomes are present in cells that specialize in producing which of the following molecules?
Definition
proteins
Term
Which structure is the site of synthesis of proteins that may be exported from the cell?
Definition
Rough ER
Term
The liver is involved in detoxification of many poisons and drugs. Which of the following structures is primarily involved in this process and therefore abundant in liver cells?
Definition
Smooth ER
Term
One of the key innovations in the evolution of eukaryotes from a prokaryotic ancestor is the endomembrane system. What eukaryotic organelles or features might have evolved as a part of or as an elaboration of the endomembrane system?
Definition
Nuclear envelope
Term
Cyanide binds with at least one molecule involved in producting ATP. If a cell is exposed to cyanide, most of the cyanide will be found within...
Definition
mitochondria
Term
Which cell would be best for studying lysosomes?
Definition
phagocytic white blood cell
Term
Some regions of the plasma membrane, called lipid rafts, have a higher concentration of cholesterol molecules. As a result, these lipid rafts..
Definition
Are more rigid than the surrounding membrane
Term
Singer and nicolsons fluid mosaic model of the membrane proposed that
Definition
membranes consist of protein molecules embedded in a fluid bilayer of phospholipids
Term
which of the following is true of integral membrane proteins?
Definition
They are usually transmembrane proteins
Term
Cell membranes are asymmetrical. Which of the following is the most likely explanation?
Definition
The two sides of a cell membrane face different environments and carry out different functions.
Term
Water passes quickly through cell membranes because...
Definition
It moves through aquaporins in the membrane
Term
Which of the following membrane activities require energy from ATP hydrolysis?
Definition
NA+ ions moving out of a mammalian cell bathed in physiological saline
Term
You are working on a team that is designing a new drug. In order for this drug to work, it must enter the cytoplasm of specific target cells. Which of the following would be a factor that determines whether the molecule selectively enters the target cells?
Definition
Lipid composition of the target cells' plasma membrane
Term
Increasing the substrate concentration in an enzyme reaction could overcome which of the following?
Definition
competitive inhibition
Term
Some of the drugs used to treat HIV patients are competitive inhibitors of the HIV reverse transcriptase enzyme. Unfortunately, the high mutation rate of HIV means that the virus rapidly acquires mutations with amino acid changes that make them resistant to these competitive inhibitors. Where in the reverse transcriptase enzyme would such amino acid changes most likely occur in drug-resistant viruses?
Definition
in or near the active site
Term
Which of the following statements describes ezymes cooperativity?
Definition
A substrate molecule bound to an active site of one subunit promotes substrate binding to the active site of other subunits
Term
Besides turning enzymes on or off, what other means does a cell use to control enzymatic activity?
Definition
localization of enzymes into specific organelles or membranes
Term

Where does glycolysis take place in eukaryotic cells?

 

Definition
cytosol
Term
Starting with one molecule of glucose, the energy-containing products of glycolysis are
Definition
2 NADH, 2 pyruvate and 2 ATP
Term

One function of both alchol fermentation and lactic acid fermentation is to...

 

Definition
Oxidize NADH to NAD+
Term
When skeletal muscle cells are oxygen deprived, the heart still pumps. What must the heart muscle cells be able to do?
Definition
continue aerobic metabolism when skeletal muscles cannot
Term
Phosphofructokinase is an imoprtant control enzyme in the regulation of cellular respiration. Which of the following statements correctly describes phosphofructokinase activity?
Definition
It is an allosteric enzyme
Term
If pyruvate ozidation is blocked, what will happen to the levels of oxaloacetate and citric acid in the citric acid cycle?
Definition
Oxaloacetate will accumulate and citric acid will decrease
Term
Starting with citrate, which of the following combinations of products would resul from three acetyl CoA molecules entering the citric acid cycle?
Definition
3 ATP, 6 CO2, 9 NADH, and 3 FADH2
Term
In the presence of oxygen, the three carbon compound pyruvate can be catabolized in the citric acid cucle. In the transition step between glycolysis and Krebs cycle, a two carbon molecule is bonded to a coenzyme A which is then fed into the Krebs cycle. What is the correct sequence of carbon reduction in the kreb cycle?
Definition
Acetyl CoA--OAA--Citrate
Term
The transitions phase which a combination of three steps results in the formation of
Definition
Acetyl CoA, NADH, H+, CO2
Term
Which steps of glycolysis require the input of ATP and thus are collectively called pump priming?
Definition
Steps 1-3
Term
What of the following plays a role in the degredation of proteins?
Definition
Ubiquitin and proteosome
Term
Which of the following modification marks a protein for degredation in proteosomes?

Definition

ubiquitinylation

 

Term
Peripheral membrane proteins...
Definition
May noncovalently interact with phospholipid heads
Term
Cholesterol mixes with phospholipids in a biomembrane because cholesterol molecules are..
Definition
amphipathic
Term
Which of the following conditions forms a proton gradient in the ETC?
Definition
Higher H+ concentration in the intermembrane space than matrix
Term
A protein being transported to the trans-golgi network from the ER will be taken there by _____ coated vesicles.
Definition
COP II
Term
A specific gene is known to code for three different but related proteins. This could be due to which of the following?
Definition
Alternative RNA splicing
Term
Which is not a constituent of deoxyribonucleotides?
Definition
Ribose
Term

WHat is removed from mRNA's during processing?

 

Definition
noncoding sequences
Term
In eukaryotic cells protein synthesis in the cytoplasm utilizes three types of RNA molecules. Which contains a three nucleotide sequence called the anticodon?
Definition
tRNA
Term
All the following steps are performed by the enzyme transposase during nonreplicative transposition of bacterial insertion sequences except..
Definition
Synthesis of DNA to fill in the single-stranded gaps
Term

What is not true about the nucleosome?

 

Definition
Is is the "String" of the "beads-on-a-string" appearance
Term
DNA that is transcriptionally active..
Definition
Is more susceptible to DNase I digestion (DNA is degradede or cut up by this enzyme)
Term
All of the following can be found in chromatin except
Definition
RNA
Term
Telomeres..
Definition
Consist of repetitive sequences with high G content and have a specific protein bound at the DNA ends
Term
All the following statements about heterochromatin are true except..
Definition
It is usually transcriptionally active.
Term

What is the order in which mature mRNA is produced?

 

Definition
Inititiation of transcription, addition of 5' cap, addition of poly A tail, splicing, transport to cytoplasm
Term
The plasma membane of eukaryotic cells is supported by..
Definition
actin filmanets
Term
Vesicle transport along actin filaments is driven by..
Definition
myosin I
Term
During treadmilling, actin subunits add..
Definition

predominantly to filament + ends

 

Term
Membrane extension during cell locomotion is driven by
Definition
actin polymerization
Term
The region of a motor protein that interacts with the motors cellular cargo
Definition
Tail domain
Term
Cytosolic dynein is linked to vesicles and chromosomes via
Definition
dynactin
Term
Which of the following is typical feature of prokaryotic genes?
Definition
Polycistronic messenger RNA's
Term
The TATA box..
Definition
acts to position RNA polymerase II for transcription initiaion
Term
All the following statements about heterochromatin are true except
Definition
Heterochromatin is more susceptible to DNase than euchromatin
Term
Transcriptionally inactive genes
Definition
often are methylated
Term
Which of the following variations on translation would be most disadvantageous for a cell?
Definition
Translating polypeptides directly from DNA
Term
The nitrogenous base adenine is found in all members of which groups?
Definition
ATP, RNA, DNA
Term
Which of the following statements best describes the termination of transcription in prokaryotes?
Definition
RNA polymerase transcribes through the terminator sequence, causing the polymerase to separate from the DNA and release the transcript.
Term
Which of the following does not occur in prokaryotic gene expression, but does in eukaryotic gene expression?
Definition
A poly-A tail is added to the 3' end of an mRNA and a cap is added to the 5' end.
Term
Transcription is eukaryotes requires which of the following in addition to RNA polymerase?
Definition
Several general transcription factors
Term
During splicing, which molecular component of the sliceosome catalyzes the excision reaction?
Definition
RNA
Term
When spliceosome binds to elements of this structure, where can it attach?
Definition
To the end of an intron
Term
Accuracy in the translation of mRNA into the primary structure of a polypeptide depends on specificity in the..
Definition
bonding of the anticodon to the codon and the attachment of amino acids to tRNAs
Term
Which is the first event to take place in translation in eukaryotes?
Definition
The small subunit of the ribosome recognizes and attaches to the 5' cap of mRNA
Term
Which of the following is a function of a signal peptide?
Definition
to translocate polypeptides across the ER membrane.
Term
When the function of the newly made polypeptide is to be secreted from the cell where it has been made, what must occur?
Definition
Its signal sequence must target it to the ET, from which it goes to the Golgi
Term
What is the most current description of a gene?
Definition
A DNA sequence that is expressed to form a functional product: either RNA or polypeptide
Term
tRNA its 3' end projecting beyond its 5' end. What will occur at this 3' end?
Definition
the amino acid binds covalently
Term
COP I coat proteins mediate transport between the golgi apparatus and other organelles
Definition
retrograde
Term
Protein sorting of anterograde cargo to different destinations within the Golgi complez occurs in the
Definition
trans-golgi network
Term
Within the centrosome what actually nucleates the microtubules?
Definition
y-tubulin or centriole
Term
Rapid depolymerization tubulin is called
Definition
catastrophe
Term
Catastrophe is caused by..
Definition
hydrolysis of GTP to GDP in + end
Term
Which motor protein is plus end directed?
Definition
Kinesin
Term

One symptom kartanener syndrome is immotile sperm. The mutation likely results in defective..

 

Definition
flagella
Term
The length of a particular gene in human DNA, measured from the start site for transcription to the end of the protein-coding region, is 10,000 nucleotides, whereas the length of mRNA produced from this gene is 4,000 nucleotides. What is most likely the reason for this discrpency?
Definition
Splicing
Term
You take the normal NLS and fuse it a non nuclear protein like serum albumin and inject it into the cytoplasm of the cell. You then monitor what happens to the protein. What happens?
Definition
Serum albumin moves to the nucleus
Term
Chromosomes compact using proteins called
Definition
Histones
Term
Tay-Sachs disease is a human genetic abnormality that results in cells accumulating and becoming clogged with very large and complex lipids. Which cellular organelle must be involved in this condition?
Definition
the lysosome
Term
Which structure is the site of the synthesis of proteins that may be exported from the cell?
Definition
Rough ER
Term
Which of the following contain 9+2 arrangement of microtubules, consisting of nine doublets of microtubules surrounding a pair of single microtubules?
Definition
both flagella and motile cilia
Term
Vinblastine, a drug that inhibits microtubule polymerization, is used to treat some forms of cancer. Cancer cells given vinblastine wouldn't be able to..
Definition
separate chromsomes during cell division
Term
If an individual has abnormal microtubules, due to a hereditary condition, in which organs or tissues would you expect dysfunction?
Definition
Sperm, larynx, and trachea: Cells and tissues that contain flagella or cilia
Term

Cytochalasin B is a drug that prevents actin polymerization. A cell treated with cytochalsin B will still be able to

 

Definition
move vesicles around the cell.
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