Homework questions

B and C

Which immune system(s) are absent in individuals with severe combined immunodeficiency? (choose all that apply) A - innate (inflammatory response) B - B cells and antibodies C - T cells D - all white blood cells

C

According to the lecture, how does being heterozygous or homozygous for the sickle cell allele reduce the chance of dying from malaria? A - Malaria attacks and kills red blood cells (causing anemia). The mutation forces the body to produce red blood cells faster to replace those that are lost. B - The mutation prevents red blood cells from being infected by the malarial parasite. C - The presence of the sickling allele forces the body to make more of a chemical (HO-1) that somehow prevents malaria from entering and infecting the brain. D - The mutation prevents malaria from infecting the liver (which is the initial stage of the infection).

B and C

According to the "Superbug" article, which of the following statements about plasmids are true? Multiple answers: A -Plasmid is another name for the bacterial chomosome which is different from human chromosomes because it is circular. B -Plasmids are smaller than bacterial chromosomes and contain extra genes. C - Plasmids can contain more than one resistance gene. So a single plasmid can confer resistance to multiple antibiotics. D - Plasmids help the bacterial cells to undergo meiosis which improves genetic diversity in the population E - Plasmids can only be transferred between bacteria of the same species.

A

Allergies are caused by a specific type of antibodies that recognize harmless antigens. When the antigen encounters the antibody, it activates: A - mast cells to release histamine and induce an inflammatory response B - helper T cells to activate more B cells that release more antibodies C - killer T cells to destroy local tissues D - lymph nodes which release signals that cause inflammation and asthma

D

As part of the inflammatory response, ______ engulf and destroy invading bacteria A - histmines B - T cells C - B cells D - phagocytes (white blood cells) E - mast cells

A and D

Bacteria do not reproduce sexually, so how do they generate the genetic diversity in their population needed for evolution to occur? Choose the two correct answers: Multiple answers: A - They reproduce very rapidly and occasionally DNA replication includes mistakes (mutations) B - They can pick up genetic material from their host (human or animal DNA) and get resistance to antibiotics that way C - They make new mutations in their own DNA in response to drugs like antibiotics D - They can exchange plasmid DNA with other bacteria (conjugation)

E

How do antibodies help the immune system fight invading pathogens? They bind to the pathogen and... A - act as signals to white blood cells to come engulf the pathogen B - cause pathogens to clump together, so they lose their ability to move around in the body (and allow white blood cells to engulf multiple pathogens together) C - activate the compliment system, which punches holes in bacterial cell membranes D - prevent viruses from binding to cell surface proteins, which they need to do to enter cells and infect them E - all of the above

B (If there is no Duffy protein, malarial parasites cannot enter and infect red blood cells)

How does having the Duffy protein on the surface of blood cells affect one's chances of getting malaria? A -The Duffy protein prevents the malarial parasite from infecting red blood cells. B - The Duffy protein is required for malarial parasites to enter and infect red blood cells. C - The Duffy protein is a signal to the immune system that the red blood cell is infected and must be destroyed by killer T cells.

B

How does the genetic modification work? A - Any mosquito or larva with the modified gene makes a deadly protein when infected with malaria. B - Any mosquito or larva with the modified gene will die if it does not eat tetracycline. C - Any mosquito or larva with the modified gene produces an antiviral protein that prevents the mosquito from getting viral infections D - Any mosquito or larva with the modified gene produces a protein that prevents mosquitoes from getting malaria E - Any male mosquito with the modified gene will kill any female it tries to mate with.

C

How does the protein CCR5 relate to HIV infections? A - The HIV virus make the CCR5 protein on its surface. The HIV virus uses CCR5 to enter and infect helper T cells. B - CCR5 is an antibody to HIV. CCR5 binds to HIV viruses and helps the immune system fight HIV infections C - CCR5 if a protein on the surface of helper T cells. HIV binds to CCR5 and uses it to enter and infect helper T cells D - CCR5 is a protein that T cells produce in response to HIV infection.

B

How large is the human genome? A - 3 million base pairs B - 3 billion base pairs C - 3 trillion base pairs

B

If you suspect your son has a NEW (uncommon) cystic fibrosis mutation (in the CFTR protein), what type of DNA sequencing service(s) could confirm it? A - genotyping B - exome sequencing C - whole genome sequencing D - all of the above

B

In Greece, the frequency of the sickle cell allele in the population is very low. But they have an unusually high (compared to other worldwide populations) frequency of an allele that causes beta-thalessemia, which is also protective against malaria. In Sub-Saharan Africa, the frequency of the beta-thalessemia allele is very low. Why is there such a difference in the types of mutations, given that both populations dealt with malaria over thousands of years? A - Africans are more resistant to beta thalessemia, and Greeks are more resistant to sickle cell anemia. B - In the two different populations, different mutations occurred and were selected for over time. C - The two different populations responded to malaria by generating two different mutations.

C

In Sub-Saharan Africa and areas of West Africa, 90-100% of the population has the Duffy negative allele. In the same areas, only about 30% of the population has the sickle cell allele. Why is Duffy more widespread than the sickle cell allele? A - A person is only protected from malaria if they are homozygous for either allele. But those with two Duffy negative alleles are healthier. B - A person is protected from malaria if they are heterozygous for either allele. But those who are homozygous for Duffy are healthy, and those who are homozygous for sickle cell are not. C - The Duffy negative allele does not cause any health issues, and is only effective when the person is homozygous. The sickle cell allele benefits carriers and homozygous people, but the homozygous people are at a disadvantage. D - The Sickle cell allele mutation occurred earlier in evolutionary time than the Duffy negative allele.

A

In an inflammatory response, the direct effect of histamine is to _______________ A - dilate (increase diameter of) blood vessels causing increased blood flow to the area of infection B - decrease heat accumulation in the area of infection C - directly kill bacteria D - attack cytotoxic T cells E - cause B cells to release antibodies

B

Individuals with X-linked agammaglobulinemia cannot make B cells. What are they MOST susceptible to? A - viral infections B - bacterial infections C - allergies and asthma D - cancer

A

Malaria is caused by: A - A microscopic parasite B - A virus C - A bacterium D - Mosquito bites E - A fungus

A

Of the five methods for reducing mosquito populations we discussed in class, which is the method that is MOST likely to allow mosquito populations to develop resistance to that method? A - spraying DDT B - infecting them with the B. bassania fungus C - innoculating them with the Wolbachia bacterium D - sterilizing them with radiation E - genetically modifying them

B

One article discusses how soap and bleach act differently on bacterial populations than antibiotics do. Which statement below is correct? A - Soap and bleach act by targeting a specific bacterial protein, causing it to stop functioning and killing the bacterium B - Soap and bleach act by causing mutations in bacterial DNA, which mostly kills them but occasionally accelerates their evolution C - Antibiotics target a specific protein, causing it to stop functioning and killing the bacterium D - Antibiotics trigger bacteria to create new mutations in their DNA to fight the effects of the drug E - Despite the fact that bleach and antibiotics kill bacteria in different ways, it's still the case that bacterial populations are evolving resistance to both

A (MOST of these SNPs occur between genes. Only a few occur within protein coding regions of genes, and an even smaller number change the protein code.)

One of the most common ways that people differ from each other is called SNPs. SNP stands for single nucleotide polymorphism. What is it? A - A location (locus) where a single nucleotide is different from one person to another. B - A location where a region of the chromosome is missing in some people, but not others C - A location where a region of the chromosome is duplicated in some people, but not in others D - a location (locus) where a single nucleotide causes a mutation in a protein in some people, but not others

B (- the father is heterozygous, so there is a 50% chance he will pass on the Rh+ allele - But the first child will not be in danger of HDN-- it's the subsequent Rh+ children that can be affected.)

Rh+ is dominant and Rh- is recessive. A mother is Rh- (homozygous) and the father is Rh+ (heterozygous). What is the probability that their first child will be Rh+, and will that child be in danger of HDN? A - 0%....so no B - 50%....no C - 50%....yes D - 100%...no E - 100%...yes

C

The FDA only recently prevented farmers from adding antibiotics to animal feed. The problem with using antibiotics in animal feed is that: A - The animals become resistant to the antibiotics B - Humans that eat their meat will become resistant to antibiotics. Or the humans will be exposed to high doses of antibiotics and have negative side effects from the drugs C - The doses are sub-therapeutic. The bacteria on and in the animals will become resistant to the antibiotics. The same bacteria that infect animals can also infect humans. D - Using antibiotics in animal feed reduces the quantities available in hospitals (the supply is limited)

D

The following question is from the "antibiotics vs. soap" article. The main advantage to using soap and bleach to remove bacteria from nonliving surfaces and skin instead of antibiotics is what? A - They are much more effective at killing bacteria than antibiotics and will leave the surface entirely bacteria-free B - Antibiotics are non-specific and will kill our own cells just as readily as they kill bacterial cells C - Soap and bleach are not deadly to human cells, but they are deadly to bacterial cells. D -Unlike with antibiotics there are no variations in the bacterial population that can make them more or less resistant to bleach and soap. So bleach and soap are not selective pressures.

B

The immune system "remembers" previously encountered pathogens because of: A - naive B cells B - memory B cells C - killer T cells D - mast cells E - helper T cells

E

The most effective level of defense against pathogens is the _____, because it _____. A - innate immune system; recognizes specific pathogens B - adaptive immune system; recognizes specific pathogens C - nonspecific immune system; targets all pathogens D - inflammatory response; is mediated by T cells E - skin; provides a physical barrier against pathogens

A

The second exposure to a pathogen elicits a rapid, overwhelming response by the immune system due to: A - Memory B cells, which are activated in response to the second encounter and produce massive quantities of antibodies into the blood B - White blood cells circulating in the blood that immediately recognize and activate new naive B cells C - The cells that control the innate inflammatory response D - The bone marrow can now detect the pathogen and produce extra white blood cells

B

To prevent HDN in Rh- mothers pregnant with Rh+ fetuses, mothers are given Rhogam during pregnancy. Rhogam: A - blocks all the mother's B cells from creating antibodies for the duration of the pregnancy B - contains artificial antibodies that help destroy the fetal cells before they are detected by the mother's B cells C - suppresses the mother's adaptive immune system (all cells including B cells and T cells) D - Blocks the fetus from producing Rh+ proteins E - Destroys the mother's anti-Rh+ antibodies

B, C, and E

Under what circumstances might your DNA end up in a forensic DNA database? (Choose all that apply) Multiple answers: A - If you are convicted of shoplifting B - if you happened to be at a location that was later a crime scene C - if you are a relative of a missing person D -if you are arrested for driving without a license E - if you are convicted for rape or murder

B

We briefly discussed this in class: why is it that drug companies are not rushing to discover new antibiotics? Why have there been so few new antibiotics put on the market in recent years? A - There are already so many different antibiotics in use that there is no need for new ones. B - New antibiotics are shelved until there is a dire need for them. There is no profit in making a drug that will not immediately be put into widespread use. C - Bacteria have already developed resistance to all the possible mechanisms that antibiotic drugs can use to kill them. D - We now know that the antibiotics themselves trigger individual bacteria to fight back by generating their own mutations to make themselves more resistant.

B

We often refer to human genome polymorphisms (SNPs and CNV/STRs) as "markers." What do we mean by this? Which of the following phrases is the best analogy for how companies like 23andme use them to deduce information about us? A - SNPs and STRs alter phenotypes of people, so we can use them to mark people of different races. B -SNPs and STRs act a little like barcodes. If we know the specific barcode (markers) of a region of a chromosome, we can predict rest of the entire sequence nearby (haplotype). C - SNPs and STRs cause specific mutations in people. WE don't need to know the sequence outside of them-- they are the mutations that cause diseases.

C (While it's true that most of the variations between people are not harmful and don't alter phenotypes, some of them (like eye color) do! The best answer here is the definition of mutation vs. variation-- it's entirely due to how widespread that particular difference is in the total population. 1% is a variation)

We've discussed mutations and variations in the first unit. Most of the differences between people are considered variations instead of mutations...why? A - The differences between don't involve changes to the DNA sequence itself B - Variations are inherited, and mutations happen spontaneously (not inherited) C - Variations are found in >1% of the population, mutations are found in <1% of the population D - Mutations are always detrimental, but variations don't affect phenotypes

C

When the DNA profile database is searched, we find an exact match between the crime scene sample and a convicted felon's DNA sample. We also have evidence that the felon was at the scene of the crime based on eyewitness accounts. What do we call this type of match? A - Guilty! B - A cold hit C - A hot hit D - A wet hit E - A bingo

C

What best describes B cells and antibody production? A - When a naive B cell encounters a new pathogen, it edits its DNA and produces an antibody that recognizes an antigen from the pathogen. Then the B cell multiplies to make more B cells that produce that antibody. B - A 'B cell' uses alternative splicing to produce many different kinds of antibodies on its surface. When a B cell encounters a new antigen that matches one of its antibodies, it alters its RNA to produce only that antibody. Then the B cell multiplies to make more B cells that produce only that antibody. C - A 'B cell' edits its own DNA when it is made so it only produces one type of antibody. If a pathogen has an antigen that is recognized by that B cell, that B cell multiplies to make more B cells that produce only that antibody.

E

What can a person's DNA profile tell you about them? (Choose all that apply) Multiple answers: A - Their hair color B -their race C - their chromosomal sex (XX or XY) D - their eye color E - nothing

C

What do the techniques of Sterile insect release and the genetically modified OX513A mosquito release have in common? A - They can both be performed once in an area and the mosquito population will stay reduced for a long time. B - They both require gene therapy to modify the mosquito's genomes C - They both rely on lab-grown males mating with wild females to produce nonviable (unable to hatch) eggs. D - They are both modifications that are passed on to other members of the wild mosquito population E - They both affect all species of mosquitoes, not just the target species (A. aegypti) that carries malaria

D

What is a cold hit? A - When the search returns more than one match to a DNA sample B - When the search returns the profile of someone who is a partial match C - When the crime scene sample is degraded or contains the DNA of multiple people, making the results difficult to interpret D - When the search returns a perfect match to a crime scene sample, but the identified suspect was not previously implicated in this crime E - When the search returns a perfect match but the suspect is already dead

A

What is adaptive evolution (as opposed to plain evolution)? A - Adaptive evolution describes how natural selection influences the survival of some members of a population over others, resulting in a population better suited to that environment over time. B - Adaptive evolution describes how natural selection causes a population to evolve new mutations in response to environmental challenges, improving the survival of the population over time. C - Adaptive evolution describes how a population's gene pool is improved over time to produce more evolved and more complex organisms D - Adaptive evolution describes how a population evolves an ideal way to survive a particular environment.

A

What is currently the most effective way to reduce mosquito populations all over the world? A - DDT B - non-DDT insecticides C - Genetically modified mosquitoes D - insect repellent

B

What is the advantage of using the B. bassania fungus instead of DDT? A - The fungus is not harmful to humans, but DDT can be deadly to humans. B - The mosquitoes are less likely to develop resistance to the fungus, because it does not prevent them from reproducing. C - The fungus is highly specific to just mosquitoes and does not infect and harm other insects

B

What is the best definition of evolution as it applies to a population of organisms? A - Evolution describes how individuals of a population acclimate to environmental conditions over time. B - Evolution describes how the genetic diversity (gene pool) of a population changes over time C - Evolution describes how a population improves over time. D - Evolution describes how a population responds to natural selection by creating new mutations.

D

What is the biggest disadvantage to using GMO mosquitoes? A - It has not yet been shown to reduce mosquito populations B - The genetic modification may spread to other mosquito species C - The genetic modification may spread to other animals that eat mosquitoes D - The method is labor intensive and expensive, and must be performed many times in an area to be effective E - The genetic modification produces a protein that is deadly to animals that eat the mosquitoes

D

What is the difference between the immunity created by being infected by chicken pox, and the immunity created by a vaccine to the chicken pox? A - the two mechanisms are different, but the overall effect is the same: we have antibodies against the chicken pox virus B - The vaccine is an injection of B cells that produce antibodies against chicken pox; when we get chicken pox, we make our own B cells and antibodies C - The vaccine is an injection of antibodies created artificially. If we're infected, we produce our own antibodies. D - There is no difference in the immunity-creating mechanism. In both cases B cells that recognize chicken pox are activated and leave behind memory B cells that release antibodies to chicken pox.

C

What is the job of killer T cells? A - They engulf foreign viruses B - They engulf invading bacteria C - They destroy our own cells when they are infected by a virus D - They activate the innate immune system (inflammatory response)

D

What is the term we use to describe bacteria exchanging DNA with each other? A - meiosis B - mitosis C - vertical gene transfer D - horizontal gene transfer E - binary fission

E

When a DNA sample from a crime scene or convicted offender is profiled, what information is gathered and stored from the DNA? A - the entire sequence B - just the exome (exons) C - 500,000 SNPs D - 200 variable-size regions (CNVs, STRs, indels) E - 13 STR locations

C (- Only the third couple needs to worry - The mother's body will not recognize the Rh protein - An Rh+ father can be homozygous or heterozygous, and either way there is a possibility the fetus will also be Rh+.)

Which set(s) of parents may have to be concerned about hemolytic disease of the newborn (HDN) in their children? (Choose all that apply) A: Rh+ mother, Rh- father B: Rh+ mother, Rh+ father C: Rh- mother, Rh+ father D: Rh- mother, Rh- father

C

Who has access to the DNA information itself in the CODIS databases? A - anyone with a warrant, including administrators B - the police only C - only technicians in the forensic DNA analysis labs D - anyone with a genetics background (open access) E - law enforcement officials and lab technicians

B and C

Who is most vulnerable to malaria? (What makes it a selective pressure in humans?) Multiple answers: A - Everyone- it is an indiscriminate disease B - Children (usually 5 or younger) who have not yet developed immunity to it C - Pregnant women and their fetuses D - young adults E - the elderly

C

Why are mosquitoes not very likely to develop resistance to the Wolbachia bacteria? A - The bacterium is extremely deadly, killing the insects so quickly they will not have a chance to develop a mutation to resist the bacterium B - The Wolbachia only infect mosquitoes that are already sick due to the malaria infection. The healthy mosquitoes are left to breed. C - Wolbachia infection is not harmful to the mosquitoes. It actually gives them a reproductive advantage compared to uninfected mosquitoes. D - The Wolbachia bacteria do not infect the mosquitoes themselves; it infects the parasites and viruses, keeping the mosquitoes healthy.

B

Why do local lymph nodes swell when you have a nearby infection? A - The pathogens from the infection is attacking them and they are more sensitive to pain B - B and T cells have been activated in these lymph nodes and are actively proliferating (replicating) C - Lymph nodes are the source of all the white blood cells in the body, and are producing extra white blood cells to fight the infection D - They are swelling due to the inflammatory response, where histamine causes swelling and pain

C

Why do some people carry an epi-pen, if they know that they have the potential to have a severe allergic reaction? What does the epi-pen do? A - It contains a high dose of antihistamines, which block the histamine released during an allergic reaction B - It contains a dose of epinephrine, which blocks the IGE antibodies that trigger the allergic reaction C - It contains a dose of epinephrine, which doesn't block histamine directly but has the opposite effect on blood vessels (vasoconstriction) D - It contains a does of anti-IgE antibodies, which blocks the IGE antibodies that trigger the allergic reaction.

B

Why is genetic diversity in a population important for adaptive evolution? A - Only sexually reproducing populations can evolve quickly. B - Organisms can't design new mutations in response to selective pressures; the variations to survive an environment must already be present. C - Evolution is goal-oriented and works best when there is a new phenotype to act on. D - Evolution and natural selection cause organisms to rapidly make new mutations, so organisms need a way to generate these mutations quickly.

C and D

the Sherpas of Nepal do not require extra oxygen, nor do they get sick, even though they spend their lives at 13,000 feet or higher. Their infants are healthy. What adaptations have they evolved to deal with higher altitude living? Choose all that apply: Multiple answers: A - They evolved a mechanism to generate more oxygen inside their cells B - Their blood has more hemoglobin than ours does (hemoglobin carries oxygen) C - They breathe more rapidly D - Their blood vessels are wider E - They make more blood cells but their blood cells are smaller

mygene2

they do exome sequencing - sequence just the exons

dante labs and nebula labs

they do full genome sequencing - All of the DNA (two answers)

ancestry.com and 23andme

they do genotyping - 500,000 SNPs are sequenced (two answers)