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Cell Bio- Exam 1
study for final
| Question | Answer |
|---|---|
| Which of type of bond prevents the rotation of the atoms about its axis? | Double covalent interaction between two carbons |
| Ionic bonds between molecules require energy to break relative to other non-covalent types of interations such as hydrogen bonds or van der Waals forces. | More |
| Acetyl CoA, ATP, and NADPH are examples of a class of molecules called that cells use to create a favorable (that is a net ) change in free energy (delta G) for many otherwise energetically unfavorable reactions that occur in the cell. | Activated Carrier; Negative |
| Oligosacharide differ from 2 other major class biomolecules, polypeptide, nucleic acid in that the linear structure can be and thus # of possible molecule of this class is theoretically relative to polypeptides and nucleic acids. | Branched; Greater |
| Eucaryotic cells such as osteoclasts, red blood cells, sperm or eggs, and cardiac muscle cells are said to be and have many different properties that specialize them for different functions. | Differentiated |
| The alpha helix and beta sheet are found in many different proteins because they form by | Hydrogen bonding between the polypeptide backbone |
| Amino acids are classified relative to one another based on their chemical properties, which are distinct because of their unique groups. Basic and non-polar describe two of the such groups that exist among the 20 amino acids. | 'R'; Four |
| At equilibrium the rate constant K for the reaction A+B<--> C is expressed as . If nearly all of A and B are converted to C at equilibrium, we expect that the change in free energy at equilibrium, delta G is | [C]/[A][B]; Large and Negative |
| Chromosomal DNA in eucaryotes is packaged by proteins to form chromatin. The proteins responsible for this packaging are termed and assemble with DNA to form . | Histones; Nucleosomes |
| Enzyme catalyzed reactions possess a Vmax- one half of this value corresponds to a value Km which corresponds to: | The ability of the enzyme to associate with substrate. |
| In all eucaryotic genes that contain several exons and introns it is the case that: | All of the introns will splice via the formation of lariat intermediate structures; some cell types may alternatively splice the mRNA to generate different messages |
| Teodor Svedberg was one of the first scientists to demonstrate that proteins were polymeric assemblies of amino acids. How did he do this? | By ultracentrifugation of hemoglobin |
| In eucaryotes different RNA polymerases exist where each transcribes different set of RNAs include rRNAs, mRNAs- protein coding genes, tRNAs. In prokaryotes all these classes of RNAs are also produced, h/e they are transcribed by the same RNA polymerase. | True |
| Which of these statements regarding RNA Pol II general transcription factors are correct? | TFIID protein directly binds the TATA box; TFIIH protein functions as a kinase that phosphorylates the polymerase |
| Proteins can be studied by mass spectrometry- in this method: | Proteins are fragmented and sized to identify them. |
| Eucaryotic cells can possess: | No nuclei; a single nucleus; multiple nuclei; nuclei that have different numbers of chromosomes |
| Which of the following covalent modification for proteins is most closely associated with targeting a protein for degradation by the proteasome? | Ubiquitylation |
| The production of sugars and oxygen during photosynthesis is an example of: | Anabolic Reactions |
| In prokaryotes the trp operon is regulated by: | A repressor that controls the access of the RNA polymerase to the TRP genes |
| When a gene's expression is reduced by its relocation to a site near a heterochromatin due to chromosomal alterations such as inversions or translocations, this change in expression is termed: | Positron effect |
| Cysteine residues have the ability to form bonds that can aid in stabilizing structures of proteins that are partially or entirely found outside the cell: | Disulfide |
| Bases are compounds or chemicals that: | Remove H+ ions from water |
| The cell regulates the activities of some proteins using ATP in the reversible phosphorylation of specific amino acids in proteins. Recycling activity state of proteins via the removal of these phosphates from the modified amino acids is accomplished by: | Phosphatases |
| Hartwell, Nurse and Hunt shared a Nobel Prize for their collective work in the field of biology. Which choice correctly describes their area of study? | Cell cycle control |
| The energy that "protein machines" in the cell use to accomplish tasks most often comes with: | Binding and hydrolysis of nucleotides |
| The most reliable feature distinguishing a eucaryotic from a prokaryotic cell is: | The presence of internal membranes and a nucleus |
| Cells rely on a class of molecules that produce large negative free energies when dissociated to help make biochemical reactions favorable that would otherwise be unfavorable because of a positive change in free energy. These molecules are referred to as: | Activated carriers |
| Fatty acids are examples of molecules, as they contain a acidic "head group" and a hydrocarbon tail. | Aphipathic; Hydrophilic; Hydrophobic |
| Nucleotides are an important class of biomolecules found in cells. Nucleotides are: | The building blocks of DNA and RNA but can also act as messengers or signals |
| Lysine acts as a because it H+ ions when present in aqueous solutions. | Base; Accepts |
| Alpha helices and beta sheets share a common feature, since formation of each of these structures in proteins involves hydrogen bonding interactions between | Secondary; Protons of one amino group for an amino acid and carboxyl oxygens of other amino acids in the same polypeptide chain |
| A type of interaction that helps maintain secondary and tertiary structures of many proteins that reside on the outside surface, or function outside of the cell, is that of occurring between residues. | Formation of intrapolypeptide or interpolypeptide disulfide linkages; Cysteine |
| Which of the following are likely to be disrupted by a high concentration of salt? | A complex of two proteins |
| Double stranded RNA molecules such as miRNAs and siRNAs in cells operate to: | Reduce or eliminate gene expression of specific genes at a posttranscriptional level |
| Transcription DNA-RNA is regulated by activity of proteins interact with polymerase. These proteins specify one cell type to be different from another through expressing different gene. These are classified as and possess the property that | Activators or repressors; they bind DNA sequences upstream of the mRNA start site. |
| Chromosomes are composed of which are segments of DNA wrapped around a protein core composed of | Nucleosomes; Histones |
| The "histone" code refers to: | The different posttranslational modifications of histones which change chromatin states |
| Proteins are often posttranslationally modified or regulated. Which of the following are major mechanism by which proteins can be reversibly regulated (same protein molecule in cell can undergo multiple rounds of being turned on or off by the mechanism)? | Nucleotide binding and hydrolysis; Phosphorylation and dephosphorylation |
| Which one of the following is true? | Modification by addition of ubiquitin can target proteins to the proteasome. |
| Proteins can be degraded: | By the lysosome; By the proteasome |
| involves the energetically favorable oxidation of food molecules to create percursor biomolecules and energy, while represents the energetically unfavorable processes required to synthesis macromolecules. | Catabolism; Anabolism |
| The nucleolus is: | An area of the nucleus associated with rRNA synthesis |
| For the interaction of two proteins X and Y, nearly all of the monomers made in a cell are rapidly incorporated into XY heterodimers and these dissociate very rarely. This suggests that the free energy, delta G, associated with forming the dimer is: | Large and negative |
| Formation of the peptide bond between adjacent amino acids in a protein occurs by a reaction in which water is released during the reaction. | Condensation |
| A tRNA covalently linked to its correct amino acid: | Is assembled by an amino acetyl tRNA synthetase and first enters the A site of the ribosome |
| In the protein hemoglobin, the quarternary structure of the molecule is achieved through: | Weak non-covalent interactions between the four polypeptides of the heterotetramer. |
| Enzymes | - Can organize reactions among two substrates to facilitate product formation - Can rearrange electrons in a substrate to cause it to be more reactive - Are able to be recycled an used in multiple rounds of catalysis of the same reaction |
| Reactions that breakdown polymers to monomers and consume water in the process are known as: | Hydrolysis Reactions |
Created by:
Ash T.
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