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UCF Biology Exit Exam Practice
Questions With Answers
DNA sequences in many human genes are very similar to the sequences of corresponding genes in chimpanzees. The most likely explanation for this result is that - CORRECT ANSWERS ✔✔Humans and chimpanzees share a relatively recent common ancestor It has been observed that organisms on islands are different from, but closely related to, similar forms found on the nearest continent. This is taken as evidence that - CORRECT ANSWERS ✔✔Island forms and mainland forms descended from common ancestors Of the following anatomical structures, which is homologous to the wing of a bird? - CORRECT ANSWERS ✔✔Flipper of a cetacean In Darwin's thinking, the more closely related two different organisms are, the - CORRECT ANSWERS ✔✔More recently they share a common ancestor Charles Darwin was the first person to propose - CORRECT ANSWERS ✔✔A mechanism for evolution that was supported by evidence
Which naturalist synthesized a concept of natural selection independently of Darwin? - CORRECT ANSWERS ✔✔Alfred Wallace Darwin's mechanism of natural selection required long time spans in order to modify species. From whom did Darwin get the concept of Earth's ancient age? - CORRECT ANSWERS ✔✔Charles Lyell Tropical grasslands with scattered trees are known as - CORRECT ANSWERS ✔✔Savannas Which biome is able to support many large animals despite receiving moderate amounts of rainfall? - CORRECT ANSWERS ✔✔Savanna Which of the following organisms is the most likely candidate for geographic isolation? - CORRECT ANSWERS ✔✔Land snail The main reason polar regions are cooler than the equator is because - CORRECT ANSWERS ✔✔Sunlight strikes the poles at a lower angle Which of the following is responsible for the summer and winter stratification of deep temeprate lakes? - CORRECT ANSWERS ✔✔Water is densest at 4 celsius
Which of the following obtain energy by oxidizing inorganic substances; energy that is used, in part, to fix CO2? - CORRECT ANSWERS ✔✔Chemoautotrophs Which of the following use light energy to synthesize organic compounds from CO2? - CORRECT ANSWERS ✔✔Photoautotrophs Cyanobacteria are - CORRECT ANSWERS ✔✔Photoautotrophs Which of the following contains a copy of the chromosome, along with a small amount of dehydrated cytoplasm, within a tough wall? - CORRECT ANSWERS ✔✔Endospore If this structure connects the cytoplasm of two bacteria, one of these cells may gain new genetic material: - CORRECT ANSWERS ✔✔Sex pilus Which of the following is an important source of endotoxin in gram- negative species? - CORRECT ANSWERS ✔✔Cell wall Which of the following is a structure that permits conjugation to occur?
- CORRECT ANSWERS ✔✔Sex pilus
Not present in all bacteria, this structure enables those that possess it to germinate after exposure to harsh conditions, such as boiling. - CORRECT ANSWERS ✔✔Endospore Not present in all bacteria, this cell covering enables cells that possess it to resist the defenses of host organisms: - CORRECT ANSWERS ✔✔Capsule Which of the following requires ATP to function, and permits some species to respond to taxes? - CORRECT ANSWERS ✔✔Flagellum Which statement about the genomes of prokaryotes is correct? - CORRECT ANSWERS ✔✔Prokaryotic genomes are composed of linear DNA (that is, DNA existing in the form of a line with two ends). Prokaryotic ribosomes differ from those present in eukaryotic cytosol. Because of this, which of the following is correct? - CORRECT ANSWERS ✔✔Some selective antibiotics can block protein synthesis of bacteria without effects on protein synthesis in the eukaryotic host. The typical prokaryotic flagellum features - CORRECT ANSWERS ✔✔A complex "motor" embedded in the cell wall and plasma membrane Which is the most common compound in the cell walls of gram- positive bacteria? - CORRECT ANSWERS ✔✔Peptidoglycan
What are prions? - CORRECT ANSWERS ✔✔Misfolded versions of normal brain protein What is the function of reverse transcriptase in retroviruses? - CORRECT ANSWERS ✔✔It uses viral RNA as a template for DNA synthesis What is the name given to viruses that are single-stranded RNA that acts as a template for DNA synthesis? - CORRECT ANSWERS ✔✔Retroviruses Why do RNA viruses appear to have higher rates of mutation? - CORRECT ANSWERS ✔✔Replication of their genomes does not involve the proofreading steps of DNA replication Which of the following statements describes the lysogenic cycle of lambda phage? - CORRECT ANSWERS ✔✔The phage DNA is incorporated by crossing over into any nonspecific site on the host cell's DNA Which of the following terms describes bacteriophage DNA that has become integrated into the host cell chromosome? - CORRECT ANSWERS ✔✔Prophages
Which of the following is characteristic of the lytic cycle? - CORRECT ANSWERS ✔✔A large number of phages is released at a time Which of the following accounts for someone who has had a herpesvirus-mediated cold sore or genital sore getting flare-ups for the rest of life? - CORRECT ANSWERS ✔✔Copies of the herpesvirus genome permanently maintained in host nuclei Which of the following molecules make up the viral envelope? - CORRECT ANSWERS ✔✔Glycoproteins Why are viruses referred to as obligate parasites? - CORRECT ANSWERS ✔✔They cannot reproduce outside of a host cell The host range of a virus is determined by - CORRECT ANSWERS ✔✔The proteins on its surface and that of the host Which of the following DNA mutations is the most likely to be damaging to the protein it specifies? - CORRECT ANSWERS ✔✔A base- pair deletion A frameshift mutation could result from - CORRECT ANSWERS ✔✔Either an insertion or deletion of a base
Transcription in eukaryotes requires which of the following in addition to RNA polymerase? - CORRECT ANSWERS ✔✔Several transcription factors (TFs) In eukaryotes there are several different types of RNA polymerase. Which type is involved in transcription of mRNA for a globin protein? - CORRECT ANSWERS ✔✔RNA polymerase II The "universal" genetic code is now known to have exceptions. Evidence for this could be found if which of the following is true? - CORRECT ANSWERS ✔✔If UGA, usually a stop codon, is found to code for an amino acid such as tryptophan (usually coded for by UGG only). The nitrogenous base adenine is found in all members of which group?
- CORRECT ANSWERS ✔✔ATP, RNA, and DNA Garrod hypothesized that "inborn errors of metabolism" such as alkaptonuria occur because - CORRECT ANSWERS ✔✔genes dictate the production of specific enzymes, and affected individuals have genetic defects that cause them to lack certain enzymes. Why do histones bind tightly to DNA? - CORRECT ANSWERS ✔✔Histones are positively charged and DNA is negatively charged
Which of the following help to hold the DNA strands apart while they are being replicated? - CORRECT ANSWERS ✔✔Single-strand binding proteins What is the role of DNA ligase in the elongation of the lagging strand during DNA replication? - CORRECT ANSWERS ✔✔Unwind the parental double helix The leading and the lagging strands differ in that - CORRECT ANSWERS ✔✔the leading strand is synthesized in the same direction as the movement of the replication fork, and the lagging strand is synthesized in the opposite direction. The difference between ATP and the nucleoside triphosphates used during DNA synthesis is that - CORRECT ANSWERS ✔✔The nucleoside triphosphates have the sugar deoxyribose; ATP has the sugar ribose Which of the following synthesizes short segments of RNA? - CORRECT ANSWERS ✔✔Primase Which of the following covalently connects segments of DNA? - CORRECT ANSWERS ✔✔Ligase What is the function of DNA polymerase III? - CORRECT ANSWERS ✔✔To add nucleotides to the end of a growing strand
In trying to determine whether DNA or protein is the genetic material, Hershey and Chase made use of which of the following facts? - CORRECT ANSWERS ✔✔DNA contains phosphorus but protein does not What does transformation involve in bacteria? - CORRECT ANSWERS ✔✔Assimilation of external DNA into a cell The frequency of Down syndrome in the human population is most closely correlated with which of the following? - CORRECT ANSWERS ✔✔Age of the mother Women with Turner syndrome have a genotype characterized as which of the following? - CORRECT ANSWERS ✔✔A karyotype of 45, X A cell that has 2n+1 chromosomes is - CORRECT ANSWERS ✔✔Trisomic New combinations of linked genes are due to - CORRECT ANSWERS ✔✔Crossing over Calico cats are female because - CORRECT ANSWERS ✔✔A male inherits only one of the two X-linked genes controlling hair colour
SRY is best described in which of the following ways? - CORRECT ANSWERS ✔✔A gene region present on the Y chromosome that triggers male development
