Intro to Biomolecules - Notes

All genes code for proteins. False Aminoacyl-tRNA synthetase is an enzyme whose function is to _____. link a tRNA to its corresponding amino acid What does the operon model in bacteria (prokaryotes) attempt to explain? the coordinated control of gene expression in bacteria Are viruses alive? No What do host cells provide for viruses? All the above All RNA viruses are retroviruses. False NaCl (Sodium Chloride) a molecule. False Oxygen (O2) a polar molecule. False Atoms that have the same number of protons and electrons are electrically neutral because _____. the positive charges on the protons and the negative charges on the electrons cancel each other out Since the electronegativity of O > C = H, the shared electrons in the covalent bonds of carbon dioxide (CO2) and methane (CH4) are _____. closer to oxygen in the case of CO2 Can these hydrocarbons (molecular compounds) form hydrogen bonds? No Water has an unusually high specific heat. What does this mean? A large amount of heat is required to raise the temperature of water. Water's unique properties, such as high cohesion & surface tension, high specific heat, low density as a solid, efficiency as a solvent, are due to which type of bonds between water molecules? hydrogen bonds Individual monosaccharides primarily differ in the number of carbons and _. Orientation of hydroxyl groups There are 20 common amino acids. The distinguishing feature that makes each one unique is _____. The nature of the R-group A protein is discovered that is shaped like a Y. It could be said that the protein has this shape because of _____. All of the above A mutation may create a nonfunctional protein when an original/normal amino acid is replaced by a different one. Such a change might be _____. aspartic acid to proline If the guanine content of a certain segment of double-stranded DNA is 28 percent, what is the adenine content? 22 The sequence of one strand of DNA is shown below. Which of the following is the sequence of its complementary strand of 3′ ATTTGGCC 5′? 5′ TAAACC 3′ A certain DNA molecule is determined to have a guanine content of 40 percent. If a RNA molecule is synthesized from this particular DNA, what percentage of uracil will be in the RNA? 10% Which structure is common to all three domains of life (Prokaryotes- Bacteria and Archaea; Eukaryotes)? Plasma membrane Which of these does not have at least one membrane? Ribosome Which protein is not made at the rough ER? a protein that enters the nucleus to bind with DNA Which of the following parameters is most likely to limit the maximum size of a cell? the ratio of surface area of the plasma membrane to volume of cytoplasm Which of the following statements contributes to the argument that mitochondria and chloroplasts evolved from prokaryotic endosymbionts? All of the above Ions can travel directly from the cytoplasm of one animal cell to the cytoplasm of an adjacent cell through which of the following structures? gap junctions Which statement about glycolysis is true? It occurs in the cytoplasm Which statement about the citric acid cycle is true? It makes ATP through substrate-level phosphorylation ATP synthase at the inner mitochondrial membrane makes ATP from ADP and phosphate by coupling this to which other process? allowing H+ to move down its electrochemical gradient Drugs known as uncouplers facilitate diffusion of protons across the membrane. With an uncoupler, what will happen to ATP synthesis and oxygen consumption (or reduction of oxygen to water) if the rates of glycolysis and the citric acid cycle stay the same? ATP synthesis will decrease; oxygen consumption will stay roughly the same. When donating its activated electron, the special chlorophyll in the reaction center of photosystem II is a very powerful oxidizing agent (hates losing its electrons). This is best shown by its ability to. Force the oxidation of oxygen in water to oxygen gas. Which of the following happens during the Calvin cycle? Sugars are made from CO2 At what part of the cell cycle would you see a chromosome that looks like this? M The chromosome begins the M phase looking as shown. When does it split? Anaphase How many copies of chromosome 14 do your muscle cells contain? 2 How many copies of chromosome 14 do your egg or sperm cells contain? 1 Gene expression is _. the process by which DNA directs the synthesis of proteins The type of point mutation that results in a premature stop codon is called a _________ mutation. Nonsense What is a key difference in gene expression between eukaryotic and prokaryotic cells? In prokaryotic cells, the mRNA transcript is immediately available as mRNA without processing. Which of the following is a post-translational modification of a polypeptide? Cleavage of a polypeptide into two or more chains Which of the following catalyzes the linkage between ribonucleotides to form RNA during gene expression? RNA polymerase The sickle-cell β-globin mutation is an example of a _. missense mutation The “triplet code” refers to the fact that _________. three nucleotides code for a single amino acid Insertions and deletions are called _ mutations. Frameshift One strand of a DNA molecule has the following sequence: 3-AGTACAAACTATCCACCGTC-5. In order for transcription to occur in that strand, there would have to be a specific recognition sequence, called a(n) _, to the left of the DNA sequence indicated. promoter The TATA box is a sequence with a _ that allows for the binding of _ and _. eukaryotic promoter; transcription factors; RNA polymerase II Because the bacterial cell’s DNA is not surrounded by a nuclear envelope, _ occur(s). coupled transcription and translation Genetic information of eukaryotic cells is transferred from the nucleus to the cytoplasm in the form of _. RNA When RNA is being made, the RNA base _________ always pairs with the base _ in DNA. U,A Bacteria can transcribe and translate human genes to produce functional human proteins because _. the genetic code is nearly universal The function of tRNA during protein synthesis is to _. deliver amino acids to their proper site during protein synthesis RNA molecules that function as enzymes are called _. Ribozymes _ is the synthesis of a polypeptide using information in the mRNA. Translation Stop codons are unique because they _. do not code for amino acids but instead allow a releasing factor to bind to the A site of the ribosome _ is the synthesis of RNA using information in the DNA. Transcription What is the proper order of the following events in the expression of a eukaryotic gene? 1. Translation, 2. RNA processing, 3. Transcription, 4. modification of protein. 3, 2, 1, 4 Eukaryotic processing of the primary transcript includes _. the addition of a 5ꞌ cap, a 3ꞌ poly-A tail, and the splicing out of introns The bonds that hold tRNA molecules in the correct three-dimensional shape are _. hydrogen bonds In Drosophila development, pattern development in the late embryo, larva, and adult is controlled by _. homeotic genes Cytoplasmic determinants _. are RNAs, proteins, and other substances produced by the mother and deposited in the egg The control of gene expression is more complex in multicellular eukaryotes than in prokaryotes because _. in a multicellular eukaryote, different cells are specialized for different functions In the lac operon, the inducer is _. allolactose, the isomer of lactose Although the number of genes in the human genome is surprisingly low compared to less complex organisms, the number of possible products from those genes is greatly amplified by _. alternate arrangements of exons from a primary transcript The trp (tryptophan) operon is an example of a(n) _ operon. Repressible In prokaryotic genomes, groups of functionally related genes along with their promoters and operators are found together in _. An operon In general, operons that encode the enzymes of a biosynthetic (anabolic) pathway (such as the trp operon) are _, and those encoding the enzymes of a catabolic pathway (such as the lac operon) are _. repressible; inducible In eukaryotes, histone acetylation _. promotes transcription In a eukaryote, activating transcription factors may stimulate gene expression by binding to a DNA site called a(n) _. Enhancer Post-transcriptional processing of a pre-mRNA allows for differential cell expression by a process called _. alternative splicing Gene expression in bacteria is regulated primarily by _. controlling the transcription of genes into mRNA Cell type–specific transcription is accomplished _. by specific enhancer control elements interacting with cell type–specific transcription factors In addition to a promoter, eukaryotic genes have control elements called _. proximal control elements and distal enhancers MicroRNAs binding to complementary sequences on an mRNA _. results in either blocking translation or degrading the targeted mRNA In Drosophila development, the anterior-posterior axis of the embryo is determined by _. egg-polarity genes Small noncoding RNAs (ncRNAs) called piwi-interacting RNAs, or piRNAs, _. induce the formation of heterochromatin and block the expression of movable DNA elements called transposons The lac operon is an example of a(n) _ operon. Inducible The trp (tryptophan) operon is an example of a(n) _ that is controlled by _. anabolic pathway; feedback inhibition In an inducible operon, the inducer is often the _ in the pathway being regulated; the inducer binds to the _, thus rendering it _. substrate; repressor; inactive In the trp (tryptophan) operon, the _ binds to the product of the trp operon synthesis pathway, called _, forming the _. repressor protein; tryptophan; active repressor Both repressible and inducible operons control gene expression at the level of _. Transcription Chemotherapeutic treatment for breast cancer depends on the absence or overexpression of the _ gene(s). ERa, PR, and HER2 Vaccines for viral diseases are _ and help prevent infection by _. harmless derivatives of pathogenic viruses; stimulating the immune system to mount a defense against the actual pathogen Some viruses have membranous envelopes. Where do viral envelopes typically originate from? Membranes from the host cell When a virus infects an E. coli cell, what part of the virus enters the bacterial cytoplasm? Only the nucleic acid correct Restriction enzymes help defend bacteria against viral infections by _. cutting viral DNA once it has entered the cell HIV, the virus that causes AIDS, only infects certain cells within the immune system. This is because _. the virus binds to specific receptors that are only present on certain immune cells How does a retrovirus like HIV enter a host cell? Glycoproteins on the viral envelope bind to receptors on the host cell. The viral envelope fuses with the host cell’s plasma membrane, facilitating uptake of the virus by the host cell. How are retroviruses different from other types of viruses? Retroviruses use the enzyme reverse transcriptase to transcribe a copy of DNA from their own RNA. Which of the following events occurs during the lytic life cycle of phages? The host cell usually dies, releasing many new copies of the virus. Viral DNA incorporated into a bacterial chromosome is known as a(n) _. Prophage A phage that inserts itself into the host DNA is called _. lysogenic Reverse transcription, carried out by retroviruses, is the process by which _. RNA information is copied into DNA Genomes of viruses may consist of which of the following types of nucleic acids? All of the listed responses are correct. Which of the following statements correctly describes one difference between virulent phages and temperate phages? Virulent phages replicate through the lytic cycle only, and temperate phages replicate using both the lytic and the lysogenic cycles. Why are viruses often considered to be nonliving? Viruses do not carry out metabolic processes, a primary characteristic of living organisms. Animals that harbor and can transmit a particular virus but are generally unaffected by it are said to act as a _ for that virus. natural reservoir Viruses that infect bacteria are called _. Bacteriophages When comparing DNA and RNA viruses, which mutate more quickly, and why? RNA viruses, because no proofreading is done on RNA molecules A widespread outbreak of a viral disease is called a(n) _, and a global outbreak is called a(n) _. epidemic; pandemic The phage reproductive cycle that kills the bacterial host cell is a _ cycle, and a phage that always reproduces this way is a _ phage. lytic; virulent Viruses can vary with respect to all of the following characteristics except _. the presence or absence of metabolic machinery