ANBI 139 MIDTERM EXAM QUESTIONS ANSWERED CORRECTLY LATEST UPDATE 2026

ANBI 139 MIDTERM EXAM QUESTIONS ANSWERED CORRECTLY LATEST UPDATE 2026 Give an example each of heritable and non-heritable variation: - Answers Eye color (heritable), hobbies (non-heritable). Give an example each of random and non-random events during biological evolution: - Answers Mutation (random), survival under certain environmental conditions (non-random) What happens to the rate of evolution in small populations? - Answers the rate gets higher, evolution accelerates. What are the three key ingredients of biological evolution? - Answers Replicating entities, Heritable Variation, Differential Reproduction. What is the difference between somatic cells and germ cells? - Answers Somatic cells are the majority of the cells in the body, germ cells are the ones that can give rise to gametes. Can somatic mutation be passed on to the next generation? - Answers No, only germ line mutations can. Are most mutations dangerous to the survival of the individual in which they occur? - Answers NO, most mutations appear to be neutral. Why is the evolutionary tree of life made up of branches? - Answers Because most of the time, once two populations or organisms have stopped exchanging DNA, they become incompatible and cannot start exchanging DNA again. Why is it impossible to place viruses on the tree of life? - Answers Because viruses do not contain any DNA that can be directly compared to the DNA in cellular life forms. What does convergent evolution mean? - Answers Independent evolution leading to similar outcomes (biochemistry: caffeine, anatomy: spindle shaped swimmers, behavior: paternal care of the young) What four very different perspectives on disease can be considered? - Answers Patient, Doctor/Care provider, Evolving Pathogen, Evolving Host. Give a proximate mechanisms for disease: - Answers mutation in important immune gene, e.g. interleukin 10 (IL10) Give an evolutionary explanation for disease: - Answers Hygiene hypothesis. What is the size of a human cell, a bacterium and that of a virus? - Answers Human cell 30 micrometers, bacterium ~ 3 micrometers, virus ~100 nanometers. Can a mutation in a single gene cause disease? - Answers Yes, there are over 4000 human diseases caused by a single gene mutation! What is the pathogen that causes malaria? - Answers Several species of the protozoan called Plasmodium. What is the pathogen that causes tuberculosis? - Answers The bacterium Mycobacterium tuberculosis. What is the pathogen that causes HIV/AIDS? - Answers The HIV virus, a lentivirus belonging to the group of retroviruses. why is the name SIV a misnomer? - Answers Because the virus does not cause immunodeficiency in most non-human primates. Why is it impossible to rid the world of influenza A virus? - Answers Because there is a huge and diverse reservoir of influenza viruses in wild water birds. What is unusual about prion diseases? - Answers They are caused by a mis-folded protein, not by living, replicating organisms. A mis-folded protein from outside the body, causes additional mis-folding of the patient's own prion molecules. What is the origin of the word vaccination? - Answers the latin word vacca=cow, given that cowpox was used to immunize humans against smallpox Why is the difference between variolation and vaccination? - Answers Variolation is immunization using smallpox virus, vaccination is immunization against smallpox using the related cowpox virus. How long is the haploid genome of each of our cells and how many "letters" base pairs does it contain? - Answers About 1 meter long and it contains 3 billion bp. What does chromatin consist of? - Answers Histone and non-histone proteins and DNA Give three examples of chromosomal changes during evolution? - Answers Fusion, Inversion, reciprocal translocation. How can different parts of the genome have different histories? - Answers Genetic recombination breaks apart and brings together different parts of the genome. The further apart on a chromosome two segments of DNA are, the likelier that these do not share the same precise history. What 2 different parts of our genomes do not get reshuffled but are rather inherited from one parent only? - Answers Mitochondrial DNA and most of the Y-chromosome What are the four major classes of biomolecules? - Answers Nucleic acids, proteins, lipids and glycans. How many pieces of DNA are there in the nuclear genome of a human? - Answers 46, visible as chromosome when a cell is dividing. What is a haplotype? - Answers A unique combination of DNA variants along the same strand of DNA. What are post translational modifications? - Answers Changes to protein molecules after these have been synthesized (translated from mRNA). What could be the advantage of our genomes having multiple versions (copies) of the same gene (e.g. hemoglobin)? - Answers Slightly different variants of the same gene can be used at different times during development and life (embryonic, fetal, adult). What is an enhancer (in the genome)? - Answers A stretch of DNA that interacts with transcription factors and the promoter of genes to regulate their expression. Give two examples of RNA that is functional despite the fact that it does not code for a protein - Answers Ribosomal RNA is part of the RNA translating machinery of a cell, microRNA takes on a 3 D fold and can interact with proteins to modify gene expression. Give four characteristics of the genome that can affect gene expression? - Answers Chromatin remodeling, histone modification, DNA methylation, non-coding and microRNA (+RNA binding proteins, DNA-binding proteins = transcription factors) What does the queen bee have to do with epigenetic? - Answers Enzymes acting on histone modifications in the royal jelly produced by worker bees and fed to the developing queen larva cause the same egg to become a queen rather than a worker. How can the chemical modification of histone proteins influence gene activity? - Answers Histone modifications can change the accessibility of gene expression machinery to DNA. What is the ratio of human to microbial cells in and on your body? - Answers Roughly 1 to 1. how many times smaller than you is an average bacterium? - Answers One million times How are microbiota like micro Serengetis? - Answers They represent complex communities of multiple species. How could human hosts benefit from genes in the genome of their microbiome? - Answers Microbial enzymes can digest food and generate vitamins. Name two ways in which Biological and Cultural inheritance are similar and two ways in which they differ. - Answers Both types of inheritance represent transmission of information, both are affected by change over time; cultural inheritance does not include the inheritance of genetic information and it can spread horizontally or even from younger to older generations. Give an example of an important human technology that does not fossilize? - Answers Fiber technology, ropes, strings, baskets, fabrics. How can personal names and language affect individual behavior? - Answers It allows for reputations as the actions of the named individual can be reported to a wide social network and affect that individual's social standing. What is the consequence of language and kinship terms for social organization? - Answers These allow for the formation of tribes, allowing large numbers of small groups to form very large social networks that develop cultural identities Which of the modern online services relies heavily on reputation? - Answers A. Amazon B. Ebay, C. AirBnB What is aneuploidy? - Answers Deviation from normal chromosome numbers Why were bacteria and protozoa discovered long before viruses? - Answers Because viruses are sub-cellular parasites that cannot be seen by light microscopy. What is Koch's postulate? - Answers The notion that proof for pathogenesis by an agent requires that The microorganism must be found in abundance in all organisms suffering from the disease, but should not be found in healthy organisms. The microorganism must be isolated from a diseased organism and grown in pure culture. The cultured microorganism should cause disease when introduced into a healthy organism. The microorganism must be reisolated from the inoculated, diseased experimental host and identified as being identical to the original specific causative agent. List four different types of host defenses. - Answers 1. Mucus barrier 2. Skin 3 .Antimicrobial toxins 4. Immune cells What is horror autotoxicus? - Answers The horror of having one's own powerful immune system unleashed against oneself. How much larger is a human macrophage than a bacterium? - Answers 4 to 40 times larger. How does the macrophage recognize the bacteria? - Answers By using innate immune receptors that recognize pathogen associated molecular patterns (PAMPs). How thick is human skin? - Answers around 2 mm. What is the total surface of the human skin? - Answers 2 square meters without the folds, 25 square meters with. What is mucus made of? - Answers Mucus is a hydrated biogel consisting mostly of hydrated, highly glycosylated mucin glycoproteins but also salts and anti-microbial proteins. What is the BBB (blood brain barrier) - Answers A specially tight layer inside all the blood vessels in and around the brain. What kind of information does the immune system process? - Answers Molecular information about self and non-self, consisting of composition and shape of molecules and the patterns these form. List two cell types in the body that lose their genomes as they mature: - Answers RBC platelets lens cells of the eye List three similarities between our immune system and the brain. - Answers 1. Similar number of cells, 2. long development after birth, 3. process information What are innate immune receptors? - Answers Proteins made by a host organism (germ line encoded, even in absence of immunization) that recognize molecular patterns on potential pathogens and parasites. How does the rich diversity of alleles at many of the genes encoding innate immune receptors become apparent? - Answers Individual humans can react very differently to the same pathogens. How can liquid blood rapidly form a clot? - Answers Blood is super charged with proteins that can react to contact with oxygen and form mesh works of fibers that can crosslink and entrap platelets, thus forming a clot. Horse shoe crabs and other invertebrates lack an adaptive immune system. How do these animals protect themselves against infection? - Answers Their innate immune systems produce protective proteins that recognize bacterial molecules. What does clonal selection in the immune system refer to? - Answers B-cells that make antibodies which bind antigens well, are allowed to replicate as clones, rapidly increasing the fraction of these B-cells over other, that fail to produce such antibodies. How does the adaptive immune system prevent cells from reacting against self? - Answers Developing immune cells that recognize self too strongly are forced to undergo apoptosis.(controlled cell death). Which mechanism is more important in the somatic evolution of B- and T-cells, negative selection our positive selection? - Answers positive selection How many protein chains make up a single antibody? - Answers Four, two light and two heavy chains. Give three cell types involved in innate immunity and three involved in innate immunity - Answers Innate: Neutrophil, Macrophage, Basophil; adaptive: B-cell, T-cell, T-helper cell. what is the difference between MHC and HLA? - Answers HLA is the human MHC. How does human breast milk improve infant health? - Answers It contains prebiotics and that help the infant gut be colonized by the right bacteria, probiotics in the form of bacteria, and it contains maternal antibodies that attenuate infections in the infant, and it modulates infant immune development. What does SAMP stand for? - Answers Self associated molecular patterns. Can you name four autoimmune diseases: - Answers rheumathoid arthritis: self attack on joints multiple sclerosis: self attack on central nervous system type 1 diabetes: self attack on pancreatic islet cells that secrete insulin inflammatory bowel disease: self attack on gut tissue and or associated microbes What is the concept of friendly fire in immune responses? - Answers Immune responses can result in damage to the "self", tissues or processes of our own bodies. what is a monoclonal antibody? - Answers A specific antibody made by one clone of B-cells (these can be isolated and the mass-produced by introducing the DNA sequence encoding this specific antibody into a cell line) What is an example of a behavioral defense against infection in primates? - Answers Grooming behavior, often reciprocal List 2 examples each of viral, bacterial, fungal, protozoan, helminth and prion caused diseases: - Answers viral: polio and flu; bacterial: gonorrhoea and TB; fungal: candidiasis & valley fever; protozoal: malaria and sleeping sickness; helminthal: schistosomiasis & elephantiasis; prion: Kuru and Creutzfeldt Jakobs. What is the generation time of viruses, bacteria, parasitic worms and humans respectively? - Answers viruses: minutes; bacteria: hours; worms: weeks; and humans: decades. What two key features allow most pathogens to evolve more rapidly than their hosts? - Answers Rapid generation time and high mutation rates which pathogens ahem the smallest genomes? - Answers Viruses. How can sex allow more slowly evolving hosts to survive in the face of rapidly evolving pathogens? - Answers The shuffling of genetic material via recombination between chromosomes generates novel combinations each generation. How does meiosis differ from regular cell division? - Answers Meiosis (reduction division), involves not just the doubling of DNA, but also the recombination of chromosomes and the halving of the DNA content in the resulting sex cells. What is the two-fold cost of sex? - Answers Sexually reproducing populations require twice as many individuals for the same number of reproductive events. Which kind of reproduction allows novel mutations to spread more rapidly, sexual or asexual reproduction? - Answers Sexually reproducing populations. Can you think of an example of viral sex? - Answers Viruses can have segmented genome (influenza A) and co-infection of two different viruses can lead to recombined viral progeny. What is a molecular polymorphism and give an example. - Answers Inherited molecular variation where at lest 1% of the population differs from the rest, e.g. ABO histo-blood groups. What does "secretor" mean in the context of ABO blood groups? - Answers Most people also produce the ABO antigens (glycans) on their secretions, a minority of people only produce them within their blood vasculature (non secretors). What kind of molecular receptors are used by Norovirus (infamously knowns a "cruise ship viruses")? - Answers ABO antigens (glycans). How is infection by an enveloped virus like a nano-transplantation? - Answers Enveloped viruses are wrapped (enveloped) in the cell membrane of the host in which they were produced. In a new host, this can make them antigenic. What type of infections are influenced by ABO blood groups an affect disease susceptibility? - Answers Viral, bacterial, protozoan, fungal and helminthic infections! What is hemolytic disease of the newborn? - Answers A life-threatening condition where a baby is born with maternal antibodies against its own blood What is the reason that glycans are massively involved in infection and immunity? - Answers This class of biomolecule is abundant at the "molecular frontier" of cells and tissues. Sialic acids are exploited by many important pathogens from invasion and immune evasion. How come, vertebrate hosts did not evolve away from using sialic acids on their cells? - Answers Vertebrates have become critically dependent on using sialic acids for development, they cannot afford to abolish these molecules. How can mucins be resistant to digestion? - Answers The tightly arranged glycans make it impossible for protease enzymes to digest the core protein. What is the difference between Neu5Ac sialic acid found in all vertebrate and the animal Neu5Gc sialic acid lost in the human lineage? - Answers the presence of one additional oxygen atom in the non-human Neu5Gc. What prevents a virus that uses the alphaGal antigen as a receptor from infecting humans? - Answers The complete absence of Alpha Gal on human cells! What makes pig kidneys super antigenic in a human xenotransplant recipient? - Answers The presence of alpha Gal on all pig cells combined with his levels of pre-existing anti-alphaGal antibodies in all humans. What is the difference between horizontal and vertical transmission of a pathogen? - Answers horizontal is across a population via infection, vertical is infection from parent to offspring. How can infection by multiple strains of a pathogen lad to increase virulence? - Answers It can lead to competition between strains, which can result in higher damage to the host How does the malaria parasite manipulate mosquito behavior in its favor? - Answers Plasmodium causes mosquitoes to take blood meals from more different hosts, increasing the rate of infection of humans by a single mosquito. Why do waterborne diseases tend to be rather virulent (cause very severe disease)? - Answers The pathogen is more likely to be passed on if the patient has diarrhea and vomits, ideally near water sources.....the patient does not need to walk around or look attractive to infect others. What prevents a virus that uses the alphaGal antigen as a receptor from infecting humans? - Answers The complete absence of Alpha Gal on human cells! What triggers human immune systems to form circulating antibodies to alpha Gal and ABO? - Answers The presence of alpha Gal and ABO sugar chains (glycans) on bacteria of our normal gut microbiome. What is alpha Gal syndrome? - Answers An acute immune reaction to a meal heavy with red meat after having been stung by a lone star tick What makes pig kidneys super antigenic in a human xenotransplant recipient? - Answers The presence of alpha Gal on all pig cells combined with the patient's levels of preexisting anti-alpha Gal antibodies in all humans. How can increased contact with fresh water change the pathogen regime of human populations? - Answers Through increased exposure to waterborne diseases including schistosomiasis (=Bilharziosis), guinea worm, leptospirosis etc. Why is schistosomiasis widespread in East Asia? - Answers Paddy rice agriculture forces farmers into long hours of work standing in water How could the use of a home bases contribute to disease load? - Answers It likely increased the chances of infection due to shared space and accumulation of bodily waste in a limited area. How would a larger number of prey animals contribute to altering the pathogen load? - Answers Each species carries its own collection of microbes, by handling the carcasses of more different species, human ancestors would have samples larger number of pathogens. What made hominins good at obtaining bone marrow form the long bones of large animals? - Answers Their cooperation in chasing away other predators or scavengers (hyenas and lions) and their use of stone tools to get access to fresh marrow and brain tissue after breaking the bones and skulls. List five ways in which fire massively changed the opportunities of humans before agriculture - Answers protection from predators, cooking, lighting, changing landscapes, harvesting honey. How might the regular use and fire and tuberculosis be related? - Answers Fire brings people together and damages lungs. Where are people still most affected from indoor fire smoke inhalation? - Answers Africa and India How could trade have affected the history of human diseases? - Answers Repeated long-distance contacts and exchanges could have spread infectious diseases. What novel risk did agriculture bring for people? - Answers Famine, warfare, taxation, social inequality. What is the neolithic? - Answers The period encompassing the last 12 ,000 years since humans have become sedentary, started farming/herding and developed complex societies. Farming made many new human endeavors possible, but it also ushered in or amplified the 7 Ps. List the seven P's: - Answers Poverty, Poor Health, Plunder, Politics, Power Differentials, Pathogens, Parasites How could larger cities have contributed to disease burden? - Answers 1. High density of people, better for spread of infectious disease likely to cause more social stress; 2. water supply very prone to getting infected 3. cities rely on trade, trade can bring disease.. What was the contrast in animal domestication between the Old World (Asia and Europe) and the New World (the Americas)? - Answers Far fewer animals species domesticated in the New World: dogs arrive with first waves from Asia, turkey and lama/alpaca, and guinea pig. What is the disease called pellagra? - Answers A vitamin deficiency stemming from the lack of adequate preparation of corn (lack of nixtamalization). How is it possible that doctors in 1840s were not aware of bacterial infections? - Answers It predated the notion of "microbes" or "germs", only visible by microscopes and totally overlooked by all medical traditions Name three ways in which industrial development can change disease burden: - Answers Pollution, Urbanization, Social injustice How could number of menstrual cycles be affecting female cancer risk? - Answers Hormonal fluctuation and resulting tissue remodeling in the bread and uterus associated with each cycle introduce opportunity for cancer causing mutations to occur. What is the evidence that human breastmilk contains brain food? - Answers The brains of breast fed babies differ biochemically from those of formula fed babies. list two military technologies that have caused longterm health sequelae in civilian populations. - Answers Nuclear bombs and defoliating agents (dioxin). How does paternal age affect the risk for genetic disease in a child? - Answers Most mutations happen in the father and more happen the older he is. What is iatrogenic disease? - Answers A disease caused by medical professionals. Give an example of improved technology that causes disease. - Answers Tampons with extremely good absorbance and Toxic Shock Syndrome. What is the key concept of the hygiene hypothesis? - Answers Improved hygiene, frequent use of antibiotics, and vaccination deprives children of contact with microbes and shifts the balance of the immune system towards becoming allergy/prone to auto-immune reactions. List for areas where the human footprint is particularly measurable on the planet - Answers East Asia, South Asia, Europe, and Eastern North America. Why is Africa the only continent that still has such large numbers of wild animals? - Answers African animals evolved with humans, they are people smart. Large animal on all other continents were taken by surprise when these bipedal primates with their efficient hunting tools arrived, many of them died out. What is the size of a virus? - Answers ~ 100 nanometers or 10^-7 meters How do logging roads contribute to increased contact between human and wildlife? - Answers Once in place, local humans who often are desperate to find new livelihoods follow these new road and establish camps along them and then hunt for animal proteins in areas that had very little human wild life contact.