Biology 1510 Final

If the frequency of the sickle cell is 1/8, what fraction of the population is born with sickle cell disease? Sickle cell is an autosomal recessive disease. 1/8 1/64 1/16 2/8 7/8

1/64

In regions where the frequency of the sickle cell allele is 1/8 (12.5%), what fraction of children born are heterozygous, assuming that sickle cell genotype does not affect mating? 1/8 7/8 7/64 14/64 2/8

14/64

Rachel's sister has sickle cell disease. Rachel and all other members of her family do not have symptoms. What is the probability that Rachel is a carrier of the SCD allele? 0 1/4 1/2 2/3 1

2/3

Given 200 V domain genes, 10 J segment genes and 10 D segment genes for the heavy chain, plus 20 V domain genes and 5 J segment genes for the light chain, how many different antibodies can be made?

2000000

A key to recombinant DNA technology (genetic engineering) is the ability to cut DNA at specific sites. In a genome with 50% GC content, a restriction endonuclease with a 6-base pair recognition site (such as EcoRI, that cuts at GAATTC) will cut, on average, once every ______ nucleotides. Answer with a whole number to fill in the blank. Another way to think about this question is: what is the probability that a random 6-nucleotide sequence will have the sequence GAATTC?

4096 Given that each genomic site has an equal chance of being A, G, T, or C, and the restriction endonuclease recognizes a 6-base sequence, then the RE should cut every 4^6, or 4096 nucleotides.

What are possible ways to get recombinant DNA molecules into the cells of an adult animal, or into the cells of an adult human for gene therapy? Put the recombinant DNA molecules into a viral vector that will infect the desired cells and tissues inject plasmids with the recombinant DNA into a blood vessel mix the recombinant DNA into the animal or person's food or drink transform stem cells from the animal or person with the recombinant DNA, then implant the genetically modified stem cells into the animal or patient

A & D

A plasmid for expression of a gene in a mammalian cell should have what features that would NOT be needed in a plasmid for expression of the gene in a bacterium? Select all that apply. A selectable marker, like a drug-resistance gene A eukaryotic promoter instead of a bacterial promoter A restriction enzyme site that cuts the plasmid only once, next to the promoter An origin of DNA replication

A eukaryotic promoter instead of a bacterial promoter

How does a scientific theory differ from a scientific hypothesis? A theory is an overall explanation for a major phenomenon or observation and includes hypotheses; hypotheses treat more specific observations. Theories are proposed to test scientific hypotheses. Theories define scientific laws; hypotheses are used to set up experiments. A hypothesis is an explanation for a major phenomenon or observation and includes theories; theories treat more specific observations.

A theory is an overall explanation for a major phenomenon or observation and includes hypotheses; hypotheses treat more specific observations

Which of the following is NOT true of evolution? Evolutionary relationships determined by the geological record generally do not match evolutionary relationships determined by gene sequence comparisons Only populations can evolve; individual organisms cannot evolve The gene pool of a species may containe alleles that are not useful now in anticipation of a time when changing environmental conditions will make them useful New genetic variation can be induced (caused) by a rapidly changing environment Natural selectiong does not always result in an ideal fit between an organism and its environment

A,C,D

Phylogenetic analyses based on DNA sequences are consistent with an origin of modern humans from which continent or geographic region? Africa Asia Europe Middle East Australia

Africa

Which continent contains the greatest human genetic diversity? Africa Asia Europe Asia Australia and Melanesia

Africa

HIV infects helper T cells and macrophages. If these cell populations are depleted, which aspects of the immune system will be affected? Antibody production by B cells Cytotoxic T cell activation Immune system memory All of the above None of the above

All of the above

Which of the following is NOT required for a plasmid to be used for molecular cloning? restriction site that only occurs once in the plasmid An origin of DNA replication selectable gene or "marker" (e.g., drug resistance) All of these are required

All of these are required

The Cas9 gene was cloned into a plasmid for expression of the Cas9 protein at high levels in E. coli bacterial cells. What features must this plasmid have? Select all that apply. An origin of DNA replication A selectable marker, such as antibiotic resistance A eukaryotic promoter upstream of the site where the Cas9 gene is inserted

An origin of DNA replication A selectable marker, such as antibiotic resistance

HIV infects helper T cells and macrophages. If these cell populations are depleted, which aspects of the immune system will be affected? Antibody production by B cells Cytotoxic T cell activation Immune system memory

Antibody production by B cells Cytotoxic T cell activation Immune system memory

HIV virus infects the body for the first time. It infects CD4+ (helper) T cells and begins to reproduce exponentially. What must happen next before all the rest can happen? B cells are activated to divide & make antibodies that bind to HIV Helper T cells are activated to divide & secrete immune signaling molecules Antigen-presenting cells process and present viral protein fragments on MHC molecules Cytotoxic T cells kill HIV-infected cells

Antigen-presenting cells process and present viral protein fragments on MHC molecules

The hepatitis C virus (HCV) infects the body for the first time. It infects liver cells and begins to reproduce exponentially. What must happen next in the immune response? cells are activated to divide & make antibodies that bind to free HCV Helper T cells are activated to divide & secrete immune signaling molecules Antigen-presenting cells process and present viral protein fragments on MHC molecules Cytotoxic T cells kill HCV-infected cells

Antigen-presenting cells process and present viral protein fragments on MHC molecules

Cloned animals... Are genetically identical to the nuclear donor Are phenotypically identical to the nuclear donor Develop faster than normal offspring

Are genetically identical to the nuclear donor

In your opinion, when does a human embryo acquire personhood, deserving of legal protection? At the time of fertilization or somatic cell nuclear transfer At the time of first cell division At the time of implantation into uterus At 40 days after conception When the fetus becomes capable of survival outside the womb At birth

At the time of first cell division

How is the adaptive immune response similar to evolution by selection? Select all that apply B cell and T cell populations have genetic diversity in their antigen receptors B cells and T cells whose antigen receptors best bind a foreign antigen produce more progeny cells B cells and T cells respond to foreign antigen by producing new antigen receptors with different specificities B cells and T cells modify their antigen receptors to fit antigen, then make copies of the best-fitting antigen receptors

B cell and T cell populations have genetic diversity in their antigen receptors B cells and T cells whose antigen receptors best bind a foreign antigen produce more progeny cells

The high frequency of the sickle cell allele in regions where malaria is endemic is the result of: genetic bottleneck Founder effect Directional selection Balancing selection Disruptive selection

Balancing selection

To express (transcribe and translate) a eukaryotic gene in E. coli bacteria, you should: Clone a genomic copy of the gene into a plasmid Clone the coding sequence of the gene into a plasmid Use a plasmid vector with a promoter that is recognized by E. coli RNA polymerase Both A and C Both B and C

Both B and C

What is required to activate B cells to proliferate and differentiate into plasma cells that secrete anti-HIV antibodies? HIV binding to B cell's surface antibody signals from helper T cell whose TCR recognizes HIV peptide presented by B cell B cell recognizing HIV peptide presented by an antigen presenting cell Both HIV binding to B cell surface Ig and signals from helper T cell recognition of B cell antigen presentation are required

Both HIV binding to B cell surface Ig and signals from helper T cell recognition of B cell antigen presentation are required

Many modern human populations have small amounts of DNA from what now-extinct archaic humans? Neanderthals only Denisovans only Homo floresiensis (nicknamed "hobbits") only all of the above Both Neanderthals and Denisovans, but not Homo floresiensis

Both Neanderthals and Denisovans, but not Homo floresiensis

How are HIV-reactive helper T-cells activated? By HIV binding to the T-cell receptor By TCR recognition of HIV peptides presented by MHC II By TCR recognition of HIV peptides presented by MHC I By all of the above

By TCR recognition of HIV peptides presented by MHC II

How does the immune system recognize and eliminate HIV-infected cells? Antibodies kill HIV-infected cells Phagocytic cells phagocytose and digest HIV-infected cells Helper T cells signal apoptosis in HIV-infected cells CTLs signal apoptosis in HIV-infected cells and release toxic proteins

CTLs signal apoptosis in HIV-infected cells and release toxic proteins

Many Class I and Class II MHC alleles exist in the human population; which must be matched for successful tissue grafts or organ transplants? Recall that graft rejection is mediated by cytotoxic T cells (CTLs). Class I only Class II only Both Class I and II Neither

Class I only

How does immune system recognize and eliminate HCV-infected cells? Antibodies kill HCV-infected cells Phagocytic cells phagocytose and digest HCV-infected cells Helper T cells initiate apoptosis in HCV-infected cells Cytotoxic T cells initiate apoptosis in HCV-infected cells and release toxic proteins

Cytotoxic T cells initiate apoptosis in HCV-infected cells and release toxic proteins

What enzyme would you use to rejoin DNA fragments with compatible "sticky ends"? DNA ligase Restriction enzyme DNA polymerase RNA polymerase

DNA ligase

Depletion of which cell type would most severely cripple the adaptive immune system? B cells cytotoxic T cells Helper T cells

Helper T cells

What aspect of mammalian cloning does NOT pose an ethical issue when applied to human cloning? Cloning is still inefficient - only a few percent of somatic cell transfers are successful. Cloning requires surrogate human mothers Human egg donors are required Human clones will have the memories of the original All of the above are ethical difficulties for human cloning

Human clones will have the memories of the original

Sickle cell disease results from a mutation in hemoglobin, the protein in red blood cells that carries oxygen. The hemoglobin protein is located in the cytoplasm. Where are the ribosomes that translate beta-globin mRNA located in the cell? In the nucleus In the cytoplasm, not associated with any organelle membranes Docked to the rough endoplasmic reticulum membrane Docked to the smooth endoplasmic reticulum membrane Docked to the plasma membrane

In the cytoplasm, not associated with any organelle membranes

The proposed "therapeutic cloning" approach to treat human patients____ Uses somatic cell nuclear transfer technology Involves creation and destruction of a cloned human embryo Is a means of deriving embryonic stem cell lines with the same genotype as the patient Is all of the above Is none of the above

Is all of the above

The adaptive immune response: Evolved in the common ancestor to all animals Is specific for a particular antigen Exhibits long-term memory of prior exposure to a particular antigen

Is specific for a particular antigen Exhibits long-term memory of prior exposure to a particular antigen

Kit has gone to visit Disney World. Unknown to him, he was exposed to someone with measles. Measles is an airborne disease that is one of the most infectious known. The R0 is 12-18 (on average, a single infected person will infect 12-18 other people in a population where no one is resistant). A few measles virus particles enter his lungs. Kit had never been infected with measles before, and had not been vaccinated because his parents were anti-vaxxers. The measles virus particles enter macrophages and dendritic cells in the lining of his lung airways. Which of the events listed below happens first? Macrophages and dendritic cells that have endocyted the virus particles process measles virus proteins and present viral peptide fragments on cell surface MHC Class II proteins helper T cells whose T-cell receptors recognize viral peptide:MHC II complexes become activated, and proliferate to produce both more activated helper T cells and memory T cells. B-cells who cell surface antibodies bind virus particles proliferate, producing plasma cells that secrete antibodies to measles virus Cytotoxic T cells whose T-cell receptors recognize viral peptide:MHC Class I complexes bind and kill virus-infected cells.

Macrophages and dendritic cells that have endocyted the virus particles process measles virus proteins and present viral peptide fragments on cell surface MHC Class II proteins

Why should you get a flu vaccine every year? The flu vaccine is only weakly immunogenic and requires multiple shots for it to take effect New strains of flu virus arise rapidly; this year's strain may be antigenically different from last year's The immune memory for flu is short-lived The flu virus evolves resistance to antibiotics

New strains of flu virus arise rapidly; this year's strain may be antigenically different from last year's

What does current US law say about human cloning? No legal restrictions on privately funded research. Research with human fetal tissues prohibited. Research restricted to a limited set of pre-existing embryonic stem cell lines. The 13th Amendment prohibits creation of human clones.

No legal restrictions on privately funded research.

Why can't an adult skin cell undergo embryonic development? The skin cells contain only the genes required for skin cell proteins The skin cells have lost the genes for embryonic development The skin cells have created new genes that instruct the cells to become skin cells None of the above

None of the above

For the purpose of human gene therapy, DeWitt et al. want to avoid genetically engineering a patient's cells to express Cas9 and sgRNA. Instead, they chose to treat a patient's cells with purified recombinant Cas9 protein and sgRNA. What is the most direct and easiest way to make a copy of the Cas9 gene, which is naturally found in a bacterium called Streptococcus pyogenes? The entire genome of S. pyogenes has been sequenced and is publicly available in Genbank. PCR to amplify the gene from S. pyogenes Cut S. pyogenes DNA with suitable restriction enzymes

PCR to amplify the gene from S. pyogenes

The human HBB gene has 3 exons. Which of these additional steps are required, after transcription of the gene by RNA polylmerase, before the mature HBB mRNA exits the nucleus? RNA splicing to remove introns addition of a cap at the 3' end addition of hundreds of adenine nucleotides at the 5' end all of the above no additional steps are required

RNA splicing to remove introns

The human CFTR gene is a transmembrane chloride channel that moves chloride ions into and out of cells. The gene is located on at molecular location 117,478,367 to 117,668,665 base pairs on chromosome 7. Mutations in this gene lead to cystic fibrosis. Why can't we use PCR to clone the CFTR gene from human genomic DNA? The CFTR gene is too big PCR doesn't work on human DNA Cloning human genes is illegal The human CFTR gene sequence is unknown (can't design PCR primers for it) All of the above

The CFTR gene is too big

What would a human clone be like? The clone will not have a mother. The clone will be essentially an identical twin, offset in time. The clone will have the memories of the original. All of the above. None of the above.

The clone will be essentially an identical twin, offset in time.

Which statement best matches your opinion regarding human embryonic stem cells? The destruction of the embryo is the loss of a human life, even if embryonic stem cell lines are created. If the destruction of the embryo leads to creation embryonic stem cells, then human life is not lost, but instead immortalized. Human embryos have the same importance as the tip of my finger; both have the potential to become new people.

The destruction of the embryo is the loss of a human life, even if embryonic stem cell lines are created.

What do reproductive cloning and therapeutic cloning have in common, when applied to humans? They both involve destruction of a human embryo They both require a surrogate mother to provide a uterine environment for embryo implantation and development They both involve somatic cell nuclear transfer They both require human women as egg donors

They both involve somatic cell nuclear transfer They both require human women as egg donors

The human CFTR gene has 27 exons. To clone the human CFTR gene into a plasmid vector for expression in bacteria, one could______ Use restriction enzymes to cut out the CFTR gene from human DNA and ligate it into the plasmid vector Use reverse transcriptase to make a cDNA from human cell mRNA, and then ligate adaptors containing restriction enzyme sites for cloning into the plasmid vector Use PCR to copy to CFTR gene from human DNA, and then ligate adaptors containing restriction enzyme sites to clone into the plasmid vector

Use reverse transcriptase to make a cDNA from human cell mRNA, and then ligate adaptors containing restriction enzyme sites for cloning into the plasmid vector

Which human chromosomes or DNA molecules do not undergo meiotic recombination? Select all that apply. Autosomes X chromosome Y chromosome mitochondrial DNA

Y chromosome mitochondrial DNA

Can Georgia scientists legally produce cloned human embryos or people? Yes, both therapeutic and reproductive cloning of humans are currently allowed Therapeutic cloning is permitted, but reproductive cloning of humans is banned Both therapeutic cloning and reproductive cloning of humans is banned

Yes, both therapeutic and reproductive cloning of humans are currently allowed

DeWitt et al. 2016 results clearly show that CRISPR-Cas9 system produces more deletion mutations than homologous recombination events, even when a homologous DNA segment is electroporated into the cells along with the Cas9-sgRNA ribonucleoprotein (RNP) complex. These deletions are of just a few nucleotides. What will be the consequence of these small deletions in the beta-hemoglobin (HBB) gene? Select all true statements below. a one-nucleotide deletion will affect the structure and function of the protein less than a 3-nucleotide deletion a one- or two-nucleotide deletion will render the protein completely non-functional a three-nucleotide deletion has a good chance of still making a functional beta-hemoglobin protein

a one- or two-nucleotide deletion will render the protein completely non-functional a three-nucleotide deletion has a good chance of still making a functional beta-hemoglobin protein

Which of these is NOT immunogenic (does not induce the immune response) when implanted into a vertebrate body? a virus a bacterium a protein a plastic bead a piece of plant leaf

a plastic bead

What did Darwin propose in his theory of evolution? Species evolve by natural selection Currently existing species share a common ancestor Evolution occurs by sudden occurrence of many heritable changes All of these. A and B.

a/b

CRISPR-Cas9 system ______ cuts DNA at sites that are complementary to a short guide RNA repairs damaged DNA using homologous recombination joins broken DNA ends together all of the above

cuts DNA at sites that are complementary to a short guide RNA

In mammalian reproductive cloning, the ability of a transplanted somatic cell nucleus to support embryonic development depends on the transplanted nucleus having two X chromosomes. depends on correcting all mutations in the DNA of the transplanted nucleus. depends on the size of the genome. depends on undoing chemical modifications of chromatin that restrict gene expression. increases with the age of the donor.

depends on undoing chemical modifications of chromatin that restrict gene expression.

Which of these enzymes is most likely to cut a 3,000 bp plasmid DNA molecule once and just once? A restriction endonuclease at GGATCC A restriction endonuclease that cuts at GATC A DNA ligase Cas9 with an 18-nucleotide sgRNA targeting A reverse transcriptase

endonuclease at GGATCC

Which of these factors are required for biological evolution to occur? Select all that apply. genetic variation in the population natural selection variation in acquired traits among individuals in the population a large population many generations

genetic variation in the population

B cells are activated to secrete anti-HCV antibodies by: HCV binding to B-cell surface antibodies helper T cell whose T cell receptor recognizes HCV peptide presented by B cell B cell recognizing HCV peptide presented by an antigen presenting cell

helper T cell whose T cell receptor recognizes HCV peptide presented by B cell

Which of the following statements about induced pluripotent stem cells (iPSCs) is/are true? iPSCs are cells extracted from early blastocyst-stage embryos iPSCs have the capacity to turn into many, possibly all, types of cells in the mammalian body iPSCs are created by somatic cell nuclear transfer of adult somatic cell nuclei into enucleated egg cells Both A and B are true Both B and C are true

iPSCs have the capacity to turn into many, possibly all, types of cells in the mammalian body

Where in a soluble globular protein would you expect to find a hydrophobic amino acid like valine? on the surface, accessible to solvent molecules in the interior of the protein either on the solvent accessible surface or in the interior, without preference

in the interior of the protein

Existing human embryonic stem cell lines were created from: biopsies of human fetuses developing in the womb in-vitro fertilized embryos at the blastocyst stage umbilical cord blood Embryos cloned using SCNT All of the above were used to create various human embryonic stem cell lines

in-vitro fertilized embryos at the blastocyst stage

To clone your pet cat when all you have left is a sample of its blood, you should use B-cell as the nuclear donor T-cell as the nuclear donor macrophage as the nuclear donor red blood cell as the nuclear donor Any of the above Any lymphocyte, but not red blood cells

macrophage as the nuclear donor

If the genome-edited HSPCs are transferred back to the patients with SCDs, will the edited allele be passed on to their future children? Yes No depends on what percentage of the HSPCs have the edited allele

no

Dewitt et al. found that the sgRNA and Cas9 system they developed for HBB exon 1 cut at only one other place in the human genome, at an intergenic site. From your web page reading of genome editing with CRISPR-Cas9, what would be the most common consequence of Cas9 cutting at this intergenic site, in cells treated with the sgRNA-Cas9 complex plus wild-type HBB exon 1 DNA? homology-dependent recombination with HBB exon 1 inserts HBB exon 1 at this intergenic location non-homologous end-joining repair creates a deletion mutation at this intergenic location cleavage at this site breaks the chromosome into 2 pieces, and the piece without the centromere gets lost in mitosis

non-homologous end-joining repair creates a deletion mutation at this intergenic location

Normal hemoglobin (HbA) consists of two alpha-globin and two beta-globin chains. HbA2, consisting of 2 alpha-globin and 2 delta-globin chains, is found in small quantities (3% or less) in normal people, and at higher percentages in people with sickle cell disease. The four subunit composition of HbA and HbA2 describe what level of protein structure? primary secondary tertiary quaternary

quaternary

Sickle cell disease results in severe anemia - not enouogh red blood cells to carry oxygen to the cells in the body. In an anemic patient's cells, what effect(s) does the lack of oxygen have on cellular respiration? Select all that apply. reduced rate of electron flow in the mitochondrial electron transport chain an increase in the proton gradient across the mitochondrial inner membrane a decrease in the rate of ATP synthesis by ATP synthase (oxidative phosphorylation)

reduced rate of electron flow in the mitochondrial electron transport chain a decrease in the rate of ATP synthesis by ATP synthase (oxidative phosphorylation)

Which enzymes generate "sticky ends" when they cut DNA molecules? CRISPR-Cas9 restriction endonucleases helicases All of the above A and B only

restriction endonucleases

Measles virus also infects and kills memory lymphocytes. Kit had contracted and recovered from chicken pox as a child. His younger brother has chicken pox. What should Kit do? stay away from his younger brother or anyone with chicken pox because he could get it again don't worry about it because he had chicken pox and he's now immune don't worry about it because only young children can get chicken pox he should take antibiotics as a precaution

stay away from his younger brother or anyone with chicken pox because he could get it again

Myc went to Disney World with her friend Kit, and was also exposed to measles. Measles virus also entered her lungs and into macrophages and dendritic cells. Myc was vaccinated against measles 10 years ago as a child. What happens in Myc's course of infection? The same sequence of events as in Kit, because her immunity has worn off The measles virus is inactivated by antibodies generated during the vaccination, still circulating in her body 10 years later. the same sequence as in Kit, only much faster, because she has many more memory helper T cells, memory B cells, and memory CTLs that recognize measles virus antigens than Kit has to start.

the same sequence as in Kit, only much faster, because she has many more memory helper T cells, memory B cells, and memory CTLs that recognize measles virus antigens than Kit has to start.

The Cas9 is a protein enzyme that cuts DNA at targets specified by a short guide RNA bound to it. The sgRNA includes a 20-nucleotide sequence that is complementary to the DNA strand that it will cut. If the target DNA site has to be perfectly complementary to all 20 nucleotides, approximately how many sites will be cut in the human genome for a particular sgRNA? The human genome is 3 billion (3 x 10E9) nucleotides per haploid set of chromosomes. In other, very pertinent terms for human gene therapy, if you design an sgRNA to cut at a particular site in a human gene, how many off-target sites do you think the sgRNA-Cas9 complex will cut in the rest of the genome? (Set up and solve the problem with your group.) way less than 1 site about 1 site 1-10 sites 100-1000 sites

way less than 1 site