bio test 2
Emmanuelle Charpentier
-deciphered the molecular mechanisms of the bacterial CRISPR-Cas9 immune system and repurposed it into a tool for genome editing. -uncovered the mechanism beyond the maturation of non-coding RNA key for the CRISPR-Cas9 function
A researcher treats cells with an inhibitor that prevents DNA synthesis from starting. This treatment would trap the cells in which stage of the cell cycle? A. cytokinesis B. G0 C. G2 D. G1 E. mitosis
Answer is D
What is the correct order of the stages of Mitosis? A. Metaphase, Prophase, Anaphase, Telophase, Cytokinesis B. Telophase, Prophase, Metaphase, Cytokinesis, Anaphase C. Cytokinesis, Prophase, Metaphase, Telophase, G1. D. Prophase, Metaphase, Anaphase, Telophase, Cytokinesis E. Prophase, Metaphase, Telophase, Anaphase, Cytokinesis
Answer is D
Which of the following statements about genetic diversity over two generations is FALSE? A. Genetic diversity is enhanced by random fertilization. B. Genetic diversity is enhanced by independent orientation of chromosomes at metaphase I during meiosis. C. Genetic diversity is enhanced by crossing over during prophase I of meiosis. D. Genetic diversity is enhanced by mutations. E. Genetic diversity is enhanced by homologous chromosomes in meiosis that carry different versions of genes.
Answer is D
DNA packing
Prevents access to genes for transcription
circadian clock
regulates transcription
"Count Me In" was established in 2018 as a nonprofit organization committed to advancing patient-partnered research with support from the Broad Institute, Emerson Collective, Dana-Faber Cancer Institute, and the Biden Cancer Initiative. Choose the one FALSE statement. A. Count Me In is a government supported initiative. B. In this initiative, there is an increased focus of including men and women, people of all ethnicities, and people of color. C. Patient data included genomic data, saliva, blood, and stored tumor samples, and clinical histories. D. Each cancer has a specific oncogenic signature, and therefore the medical treatment must be tailored for the patient. E. Only through very large data sets can identification of mutations common to a particular cancer group be correlated with a specific treatment approach.
Answer is A
Transfer RNA molecules A. None of these answers are correct. B. enable Okazaki fragments to be joined. C. add a cap and tail to the mRNA molecules. D. mediate the conversion of genetic information into protein sequences. E. carry mRNA molecules from the nucleus to the cytoplasm.
Answer is D
Dicer gene
essential for generation of miRNAs in mammals
Repressor
protein binds the operator & turns off or blocks gene expression
epigenetic regulation
•Modifications to DNA molecules that do not change DNA base sequence but can affect gene expression. •These chemical modifications can be inherited although the DNA sequence is not altered. •Mutations in DNA are permanent but modifications in chromatin are not.
The Hershey-Chase experiments in 1952 were important because they showed that A. DNA was the hereditary material. B. the X-ray diffraction data showed a double helix. C. the concentrations of [A] = [T] and [C] = [G]. D. a nuclear extract was made up of H, O, N, and P with a unique ratio of N to P. E. proteins were the hereditary molecules.
Answer is A
The results of the Human Genome Project have changed how we view our DNA/genome. What were the major surprises? Identify the one FALSE statement. A. A single individual's DNA was sequenced; therefore little was initially learned from it. B. Protein-encoding genes make up ~1.5% of our genome. 98.5% is noncoding DNA. C. There are millions of transposable elements that are repeated throughout the genome. D. There is repetitive DNA sequences between the genes. E. Gene control sequences (promoters, enhancers, microRNA) make up 24% of the human genome.
Answer is A
What process is illustrated below? A. The formation of gametes via meiosis. B. Fertilization C. The replacement of damaged cells D. The formation of gametes via mitosis E. The formation of single stranded RNA.
Answer is A
A carrier of a genetic disorder who does not show symptoms is most likely____________ to transmit it to offspring A. homozygous for the trait and unable B. heterozygous for the trait and able C. None of these answers are correct. D. heterozygous for the trait and unable E. homozygous for the trait and able
Answer is B
A mouse that has the genotype AANnPpzz will have the same phenotype as a mouse with which genotype below. Note that the uppercase alleles A, N, P, and Z are dominant. A. AAnnPPZz B. AaNNPPzz C. AaNNPpZz D. AANNPPZZ E. AANnppZz
Answer is B
James Allison and Tasuku Honjo were awarded the 2018 Nobel Prize in Physiology or Medicine because of which one of the following? A. They identified key proteins that are normally responsible for turning off sickle cell anemia. B. They identified key proteins on T cells, called immune checkpoint proteins, that were normally responsible for turning off activated T cells. C. They developed a new CRISPR strategy to fight cancer. D. They were responsible for the shotgun method of sequencing. E. They patented the BRCA1 and BRCA2 genes and developed a diagnostic test for breast cancer.
Answer is B
During which stage of meiosis does crossing over and formation of tetrads occur? A. metaphase I B. prophase II C. prophase I D. interphase II E. interphase I
Answer is C
Hemophilia is an X-linked recessive condition characterized by excessive bleeding with injury. A woman who carries the gene but is not affected marries a normal man. What proportion of the couple's sons is expected to have hemophilia? A. 100% B. 0% C. 50% D. 75% E. 25%
Answer is C
Most genetic disorders of humans are caused by A. dominant alleles. B. multiple alleles. C. recessive alleles. D. drinking during pregnancy. E. a mutation that occurs in the egg, sperm, or zygote
Answer is C
Over the past 10 years we have learned a great deal about cancer through genomics projects such as The Cancer Genome Atlas (TCGA) Project. Which one of the following is FALSE? A. Chromothripsis can occur in >50% of soft-tissue cancer types. B. Every individual tumor is distinct with regard to genetic alterations, but pathways affected in different tumors may be similar. C. All breast cancers show the same oncogenic signature. D. ~140 genes are known whose mutations drive cancer. E. Most cancers are caused by 2-8 sequential alterations over 20-30 years.
Answer is C
Scientists commonly choose white blood cells that are going through mitosis to prepare karyotypes. Why? A. Karyotypes are based on chromatin and not chromosomes. B. Cells in mitosis have the fewest chromosomes, thus simplifying karyotype analysis. C. Chromosomes are more condensed during mitosis than interphase. D. More cells are in mitosis than any other stage of the cell cycle, making it easier to obtain mitotic cells for study. E. Cells in mitosis contain the greatest number of chromosomes, thus providing more material for study.
Answer is C
Why is the inheritance of so many traits difficult to explain using only Mendel's view of genetics? A. Mendel worked with peas, not humans, and the genetic principles that operate in a simple organism like a pea plant cannot be applied to an organism as complex as a human. B. Mendel's laws of segregation and independent assortment apply only in a limited set of cases in sexually reproducing organisms. C. Mendel was correct for the traits he investigated, but his principles must be extended (not discarded) to explain more complex patterns of inheritance. D. Mendel did not know about chromosomes, so he could not have been expected to describe the laws of inheritance. E. Failures in the predictive power of Mendel's ideas about inheritance are artifacts that reflect our incomplete understanding of the organisms under study.
Answer is C
During DNA replication, one DNA strand is copied to make a new DNA molecule composed of two DNA strands. This new DNA molecule contains A. 25% of the parent DNA. B. 75% of the parent DNA. C. 100% of the parent DNA. D. 50% of the parent DNA. E. none of the parent DNA.
Answer is D
In 1990, Mary Claire King identified the gene associated with increased risk of breast cancer. Based on her initial work, we now know the following except one FALSE statement A. BRCA1 is localized to chromosome 17. B. BRCA1 and/or BRCA2 mutations increase the risk for breast cancer. C. Dr. King developed the BROCA diagnostic test in 2015, which can screen for 50-60 genes in patients suspected of a predisposition to hereditary cancers. D. Dr. King argued before the Supreme Court that naturally occurring DNA should be patent eligible. E. BRCA1 and BRCA2 encode for proteins involved in DNA repair.
Answer is D
The 3-D structure of RNA is very different from DNA. Why? Choose the one FALSE statement. A. the 2'-hydroxyl (-OH) makes RNA more chemically reactive. B. the base pairing prevents formation of an anti-parallel double helix. C. a series of ribonucleotides connected by covalent bonds. D. phosphodiester linkages between the nucleotides. E. RNA has the nitrogenous base uracil.
Answer is D
The goals of the Vertebrate Genome Project 2021 include the following except one. Identify the one FALSE choice. A. To develop new algorithms for near complete genome assemblies. B. To define the genomics of vocal learning, flight, loss of limb, and aquatic/terrestrial adaptations. C. To generate near error-free reference genome assemblies of 70,000 extant vertebrate species. D. To understand cancer and rare genetic diseases in animals. E. To reconstruct common ancestor genomes.
Answer is D
Which of the following was a novel deduction that Watson and Crick were able to make about DNA based on Rosalind Franklin's X-ray diffraction data, i.e., Photo 51? A. DNA was composed of nucleotides. B. Chromosomes are the locations of our genes encoded by sequences of nucleotides. C. None of the choices stated. D. The consistent width of DNA meant that purines must base-pair with pyrimidines. E. The amounts of A = T and C = G is the same in all DNA molecules.
Answer is D
CRISPR/Cas9
can edit the genome
Lac operon w/ lactose
operon is on
RNA virus examples
-H1N1: influenza -Ebola: hemorrhagic fever, single-stranded RNA. -Dengue fever: "bone breaking disease" migration from tropics to Gulf Coast to Texas to CA -Zika: infant brain disorders, microcephaly, Guillain-Barré syndrome -West Nile & other EIDs causing encephalitis -HIV or AIDS: 2 individual single RNA strands -SARS, MERS, SARS-CoV-2: single stranded RNA
ENCODE project findings
>80% contains elements linked to biochemical function. Not junk! 18,400 RNA genes/20,687 protein-encoding genes ~1-2% of genome (2018: 25,525 RNA/21,306 protein encoding). 76% of genome transcribed into RNA as end-product, not protein. RNA is the functional unit of genome & fundamental unit of heredity. 5% of human genome conserved across mammals. 4% of human genome, not conserved across mammals, is conserved between individuals, i.e., human lineage. 42% of genome accessible by transcription factors (TFs). Evolution can occur by selection for RNA sequences that alter gene regulation, not just selection for protein sequences.
Spike protein
A protein sticking out from the surface of the virus. Usually interacts with host cells.
transcription factors
A regulatory protein that binds to DNA and affects transcription of specific genes; can be activators or silencers
Cells with two of each kind of chromosome are described by the term A. diploid B. polyploid C. triploid D. tetraploid E. haploid
Answer is A
The Central Dogma in molecular biology refers to A. DNA to RNA to Protein. B. RNA to Protein to mRNA. C. RNA to DNA to RNA. D. None of these choices. E. Protein to RNA to DNA.
Answer is A
Which of the following is true about double-stranded DNA? A.It is shaped like a triple helix. B. Adenine and uracil are present in equal amounts. C. Its 3-D conformation is quite different from RNA's 3D conformation. D. The two strands are identical. E. Adenine and cytosine are present in equal amounts.
Answer is C
Epidemiology
Branch of medical science concerned with the incidence, distribution, and control of diseases that affect large numbers of people.
antigenic shift
Large changes in genetic makeup; New combinations; the immune system sees it as a new virus.
Jennifer Doudna
Leader in CRISPR revolution -investigated RNA protein interactions
Lac operon w/ no lactose
Operon is off. Repressor bound to operator. RNA polymerase cannot bind. Repressor is constitutively expressed.
antigenic drift
Small changes in the viral genetic make-up; Not a new strain
Viral adaption
Virus can adjust to host such that evades cell defense mechanisms. Takes over cellular metabolism for virus benefit
operon
a functioning unit of DNA containing a cluster of genes under the control of a single regulatory promoter
Lac operon
a gene system whose operator gene and three structural genes control lactose metabolism in E. coli
homeotic gene
a gene that controls the development of a specific adult structure
zoonotic
able to move through the animal-human barrier; transmissible from animals to humans (cause of most pandemics)
miRNA
binds complementary sequence of mRNA; Limb patterning is dependent on this; regulate proper level of translation of mRNAs; have been found to regulate the translation of 1000s of mRNAs during development
Epigenetic variations
can explain differences in identical twins
alternative RNA splicing
can lead to multiple mRNA transcripts
Noncoding RNAs
degrade mRNA or block its translation.
Feng Zhang
developed new tool to edit RNA
endemic
disease is maintained in the population, wide geographic distribution. Ex. Common cold.
Sporadic
disease occurs occasionally in low numbers, not geographically confined. Ex. Tetanus, rabies, plague, measles.
DNA viruses
have DNA proofreading mechanisms mutate less frequently
DNA virus examples
hepatitis, chicken pox, herpes infections
EID
infections that recently appeared or whose incidence or geographic range is rapidly increasing or threatens to increase in the near future.
Epigenetic inheritance
inheritance of traits transmitted by mechanisms not directly involved in nucleotide sequence
mRNA splicing
introns are removed & exons spliced together; Occurs in the nucleus not cytoplasm
Pandemic
new incidences of the disease increase & spread rapidly, very wide global distribution. Ex. HIV/AIDS, 1968 H3N2 (Hong Kong flu), COVID-19
Epidemic
new incidences of the disease increase rapidly, but geographically confined. Ex. SARS
about transcription factors
recognizes a specific DNA sequence or motif; can block RNA polymerase, the enzyme that transcribes DNA to mRNA or activate it as does TATA Box-Binding Protein; •~2600 proteins (10% of human genome)
Adaptive Immunity
refers to the use of antibodies to defend the body from pathogens. "Custom-tailored" to each specific invader
Promoter
region of DNA that facilitates transcription of gene(s) site for RNA polymerase to bind DNA
Operator
region on DNA near promoter acts as switch for gene expression to be on or off determines whether RNA polymerase can bind to promoter
siRNA
similar to miRNA but double-stranded
herd immunity
the resistance to the spread of a contagious disease within a population that results if a sufficiently high proportion of individuals are immune to the disease, especially through vaccination.
RNA viruses
unusual high rate of mutation. Lack the proofreading mechanisms seen in DNA
Ring vaccination
used when a new case of disease is reported, All people who have been in contact with/live close to the patient are vaccinated