Bio 180 Practice Questions and Vocab

If you are doing a linear regression, what is the slope of the line predicted by the null hypothesis?

0

How many DNA molecules make up an unreplicated chromosome?

1

How many DNA molecules make up a replicated chromosome?

2

If we calculate means (averages) based on scores from 100 1st-year students and 400 2nd-year students, which is likely to have the smaller standard error?

2nd-year students, because we sampled more.

How many DNA molecules are present in a synapsed pair of homologous chromosomes?

4

What's the difference between a gene and an allele?

An allele is a version of a gene.

At the molecular level, what is a mutation?

Any change in a DNA sequence

In August of 2020, D. R. Boulware and colleagues published a research report in the New England Journal of Medicine. The scientists had studied ~800 volunteers who had no symptoms of illness, but who had recently been exposed, at home or at work, to someone infected with SARS-CoV-2, the virus that causesCovid-19. They assigned the volunteers at random to two groups. One group received pills containing the drug hydroxycholoroquine; the other group got a placebo (pills containing no medicine). Two weeks later, the scientists tested the volunteers to see if they were infected with the virus. The graph summarizes the results. The vertical black lines at the tops of the bars represent ± 1 standard error. The scientists report a p-value of 0.35. In ONE sentence, what does this mean?

Assuming the null hypothesis is true, there is a 35% chance that an experiment like this one would yield a difference between groups at least as large as the one that appears in the graph.

Which of the following happens during interphase, before mitosis or meiosis?

Chromosomes replicate (each consists of two sister chromatids).

What's the difference between a haploid cell and a diploid cell?

Haploids have one of each type of chromosome; diploids have two of each type.

When a biologist describes an allele, d, as recessive to another allele, D, he means that:

Heterozygotes have the same phenotype as DD homozygotes.

When a biologist says that an allele, D, as dominant to another allele, d, she means that:

Heterozygotes have the same phenotype as DD homozygotes.

If we want to plot the distribution of scores on Exam 1, we should use a...

Histogram

If we want to plot the exam scores of 1st-year students versus 2nd-year students, we would use a ...

Histogram or bar chart

In August of 2020, D. R. Boulware and colleagues published a research report in the New England Journal of Medicine. The scientists had studied ~800 volunteers who had no symptoms of illness, but who had recently been exposed, at home or at work, to someone infected with SARS-CoV-2, the virus that causesCovid-19. They assigned the volunteers at random to two groups. One group received pills containing the drug hydroxycholoroquine; the other group got a placebo (pills containing no medicine). Two weeks later, the scientists tested the volunteers to see if they were infected with the virus. The graph summarizes the results. The vertical black lines at the tops of the bars represent ± 1 standard error. In ONE sentence, what is the null hypothesis?

Hydroxychloroquine has no effect on the risk that a recently exposed person will develop Covid-19

X and Y chromosomes follow the principle of segregation. What does this mean?

If an individual is XY, then each gamete gets one X or one Y.

What does it mean to claim that an acquired character is passed on to offspring?

If an individual's traits change during its lifetime, its offspring have the new version of trait.

What does it mean to say that an acquired character can be inherited?

If an individual's traits change over the course of its lifetime, those changes will be passed on to offspring.

Which of the following is the most important difference between the events of prophase in mitosis versus meiosis I?

In meiosis I, homologs synapse.

Which of the following is the correct definition of haploid number?

The number of different types of chromosomes present.

Which of the following is the correct definition of ploidy?

The number of each type of chromosome present.

What was the central claim of the theory of blending inheritance?

The physical matter responsible for traits blends within individuals, like pigments in paint.

In August of 2020, D. R. Boulware and colleagues published a research report in the New England Journal of Medicine. The scientists had studied ~800 volunteers who had no symptoms of illness, but who had recently been exposed, at home or at work, to someone infected with SARS-CoV-2, the virus that causesCovid-19. They assigned the volunteers at random to two groups. One group received pills containing the drug hydroxycholoroquine; the other group got a placebo (pills containing no medicine). Two weeks later, the scientists tested the volunteers to see if they were infected with the virus. The graph summarizes the results. The vertical black lines at the tops of the bars represent ± 1 standard error. In ONE sentence, what does a comparison of the heights of the two colored bars indicate?

The rate of Covid-19 was somewhat higher among volunteers who got the placebo than in the volunteers who got hydroxychloroquine.

What does a ratio report?

The relationship between numbers of the same kind (so it is unitless).

When you look at a drawing or photograph of chromosomes, how can you tell if they are replicated or unreplicated?

Unreplicated chromosomes consist of a single "thread"; replicated chromosomes have two "threads."

In guinea pigs, BB, Bb = black; bb = white and LL, Ll = short hair; ll = long hair. A breeder mates a black, long-haired guinea pig with a bbll guinea pig. What question is the breeder trying to answer by performing this cross?

What is the coat-color genotype of the black longhair?

Today, biologists boil Darwin's four postulates down to two conditions that result in evolution. What are these conditions?

When 1) certain heritable traits are associated with 2) higher numbers of offspring produced.

Hormones called angiogenesis inhibitors (here, AI's) slow the rate at which blood vessels grow into tissues. A tumor is a growing lump of tissue. It cannot grow beyond a certain size unless blood vessels grow into it. This suggests the hypothesis that AI might be useful anti-cancer drugs. Design an experiment to test this hypothesis. You have laboratory mice into which you can implant tumors, a supply of AIs, and an unlimited supply of cages, water, and mouse chow. What is your independent variable?

Whether AI is given to the experimental mice.

What is sex-linkage, X-linkage, and Y-linkage?

X-linked alleles are on the X chromosome; Y-linked alleles are on the Y chromosome; both are sex-linked.

In this class and other classes at UDub, you'll write X-linked alleles as XR and Xr. If you're keeping track of more than one X-linked allele at a time, you'd write the chromosomes as XRB and Xrb (or whatever the genotype actually is for the R and B genes). Suppose a male human carries an X chromosome with the R allele and the b allele. How would you write his genotype?

X^Rb Y

Why is it considered important that there is "internally consistent" support for the theory of evolution by natural selection?

You can be more confident that an idea is correct if several different types of evidence support it.

What is another name for a pure-breeding line or population?

homozygous

What is the difference between an individual's phenotype and genotype?

phenotype is appearance; genotype is the alleles present

The chromosome theory of inheritance is based on the claim that genes are found on chromosomes. If you were going to build a physical model of a chromosome from everyday materials to demonstrate meiosis (including crossing over), which of the following would work best?

strings of pop beads (each bead is a gene)

In a strand of DNA, what other base does the base called adenine bond to?

thymine (A-T)

What pattern components do typological thinking and the scale of nature have in common?

Species are recent, unrelated to each other, and do not change through time.

What is the pattern component of Lamarckian evolution?

Species change in a progressive manner--meaning that they get larger and more complex over time.

In biology, what does the word fitness mean?

The ability to survive and reproduce.

What's the process component of the chromosome theory of inheritance?

The behavior of chromosomes during meiosis I.

How many chromosomes does the cell contain?

The cell contains six chromosomes

What is the cell's haploid number—and how do you know?

The cell's haploid number is three—because there are three different sizes/shapes of chromosome.

What is the cell's ploidy—and how do you know?

The cell's ploidy is 2—because the cell contains two homologs for each chromosome.

What does the pattern component of the theory of evolution by natural selection state?

The characteristics of populations change over time, in response to changes in the environment.

Are its chromosomes replicated or unreplicated—and how do you know?

The chromosomes are replicated—because the sister chromatids are present (and still attached to each other).

Consider what will happen next as this cell continues with the process of division. Describe two alternative versions that are, with regard to genes F and G, meaningfully different.

The chromosomes carrying genes F and G could line up like this: Ff Gg or like this: Ff gG

In August of 2020, D. R. Boulware and colleagues published a research report in the New England Journal of Medicine. The scientists had studied ~800 volunteers who had no symptoms of illness, but who had recently been exposed, at home or at work, to someone infected with SARS-CoV-2, the virus that causesCovid-19. They assigned the volunteers at random to two groups. One group received pills containing the drug hydroxycholoroquine; the other group got a placebo (pills containing no medicine). Two weeks later, the scientists tested the volunteers to see if they were infected with the virus. The graph summarizes the results. The vertical black lines at the tops of the bars represent ± 1 standard error. In ONE sentence, what conclusions can we draw from the data and the analysis?

The data don't provide sufficient reason to reject the null hypothesis

C. elegans is a tiny worm that lives in soil. Pei-Yin Shih and colleagues studied C. elegans from Bristol and Hawaii. They exposed worms, in groups, to a dangerous concentration of arsenic. All the worms tested in (a) had been reared in the lab under standard conditions. In ONE sentence, what does this allow us to conclude about the cause of the difference between worms from Bristol versus Hawaii?

The difference in average arsenic resistance is due to a genetic difference between the populations.

Look at the bottom graph in Figure 22.12 and at Figure 22.13. Why didn't beak size change much for several years after the 1978 drought?

The environment changed, and large-beaked individuals no longer had higher fitness than other birds.

Which of the following statements is the best way to characterize the standard error?

A measure of how precise our estimate of the mean is.

What is a genetic locus?

A particular position on a chromosome.

What's a gamete? (Note that this term is used in the reading but not explicitly defined. If you need to, you can look it up in the glossary.

A reproductive cell (sperm or egg).

What is a model organism?

A species that is easy to work on. Also, results from this species are relevant to many other species.

What is an autosomal trait?

A trait associated with a gene on a non-sex chromosome.

In biology, what does the word adaptation mean?

A trait that increases fitness in a certain environment.

What's the difference between a chromosome and a chromatid?

After replication, a chromosome consists of two chromatids.

C. elegans is a tiny worm that lives in soil. Pei-Yin Shih and colleagues studied C. elegans from Bristol and Hawaii. They exposed worms, in groups, to a dangerous concentration of arsenic. The data labeled "Mono" represent a closely related species of worm that lives in Mono Lake in California—a landlocked lake containing a high concentration of arsenic. In TWO or THREE sentences, how would an evolutionary biologist explain how the population of worms in Mono Lake came to have a different tolerance for arsenic versus the worms from Bristol and Hawaii?

Among the worms in the Mono Lake ancestral population (as in C. elegans) some worms had low arsenic tolerance while others had high tolerance—and tolerance was passed genetically from parents to offspring. Thanks to the high arsenic concentration in the lake, the worms with high tolerance were better at surviving to adulthood and making babies. After many generations, the population contained only highly tolerant worms.

What is double and helical about the double helix?

Double: two strands of DNA; helix: bonded strands form a spiral

What does the process component of the theory of natural selection state?

Evolution occurs because individuals with certain heritable characteristics produce the most offspring.

Which of the following is correct?

F1s are the first generation in an experimental cross; F2s are the second.

What is "particulate" about particulate inheritance?

Genes retain their physical integrity over time, like particles--they don't blend together.

In August of 2020, D. R. Boulware and colleagues published a research report in the New England Journal of Medicine. The scientists had studied ~800 volunteers who had no symptoms of illness, but who had recently been exposed, at home or at work, to someone infected with SARS-CoV-2, the virus that causesCovid-19. They assigned the volunteers at random to two groups. One group received pills containing the drug hydroxycholoroquine; the other group got a placebo (pills containing no medicine). Two weeks later, the scientists tested the volunteers to see if they were infected with the virus. The graph summarizes the results. The vertical black lines at the tops of the bars represent ± 1 standard error. In ONE sentence, what is the hypothesis the scientists sought to test with their experiment?

In people recently exposed to SARS-CoV-2, hydroxychloroquine reduces the risk of developing an active viral infection.

The top graph in Figure 22.12 indicates that beak depth is variable in this population. What evidence did the researchers have that at least some of this variation was heritable?

In the next generation (in offspring of individuals who survived), average beak size was larger.

With regard to genes F and G, which of Mendel's principles have you just described?

Independent Assortment

For the purposes of this course, which of the following is the best working definition of DNA?

Information archive

For the purposes of this course, which of the following is the best working definition of mRNA?

Information carrier

What does it mean to say that a mutation is "silent" or "neutral"?

It changes the genotype, but not the phenotype.

What does it mean to say that a mutation is deleterious?

It lowers fitness

What does it mean to say that something--like a gene--"segregates"?

It separates. In the case of a gene, the two alleles present in a parent separate and go into different gametes.

The diagram above shows the design of an experiment by education researcher Nate Kornell. Across four consecutive days, student volunteers studied a total of 40 flash cards, each with a pair of words that were synonyms (such as effulgent: brilliant). On Day 1, the students looked at cards 1-20 twice each and cards21-25 eight times each. On Day 2, the students looked at cards 1-20 twice each, cards 26-30 eight times each, and so on. Kornell refers to studying a card lightly each day as "Spaced" studying; studying a card intensely on a single day is "Massed" studying. On the fifth day, the students took a test covering all 40 cards. Their average performance on the different groups of cards is graphed here: In ONE sentence, what is the take-home message for a student wanting to do well on exams in Biol 180?

Kornell's study suggests that cramming on Thursday works better than cramming on Tuesday, but—all else being equal—studying a little bit every day on Monday, Tuesday, Wednesday, and Thursday is the best strategy.

For the purposes of this course, which of the following is the best working definition of a protein?

Machinery that performs a function in the cell

The diagram above shows the design of an experiment by education researcher Nate Kornell. Across four consecutive days, student volunteers studied a total of 40 flash cards, each with a pair of words that were synonyms (such as effulgent: brilliant). On Day 1, the students looked at cards 1-20 twice each and cards21-25 eight times each. On Day 2, the students looked at cards 1-20 twice each, cards 26-30 eight times each, and so on. Kornell refers to studying a card lightly each day as "Spaced" studying; studying a card intensely on a single day is "Massed" studying. On the fifth day, the students took a test covering all 40 cards. Their average performance on the different groups of cards is graphed here: Many students wait until the night before an exam when they study intensely. Which TWO bars represent the best analogy to comparing cramming the night before an exam versus studying a little bit each day during the week before the exam?

Massed Session 4, representing cramming the night before, versus Spaced, representing studying a little bit each day

What's the pattern component of the chromosome theory of inheritance?

Mendel's rules: the principle of segregation and the principle of independent assortment, because genes are found on chromosomes.

What is "meta" about metaphase?

Meta means "between"; chromosomes move to the middle of the cell--between the two poles.

The diagram above shows the design of an experiment by education researcher Nate Kornell. Across four consecutive days, student volunteers studied a total of 40 flash cards, each with a pair of words that were synonyms (such as effulgent: brilliant). On Day 1, the students looked at cards 1-20 twice each and cards21-25 eight times each. On Day 2, the students looked at cards 1-20 twice each, cards 26-30 eight times each, and so on. Kornell refers to studying a card lightly each day as "Spaced" studying; studying a card intensely on a single day is "Massed" studying. On the fifth day, the students took a test covering all 40 cards. Their average performance on the different groups of cards is graphed here: In ONE sentence, what is the pattern in the data as regards massed versus spaced studying?

On average, the students earned better exam scores on the cards they studied in the Spaced pattern than they did on the cards they studied in the Massed pattern.

In guinea pigs, BB, Bb = black; bb = white and LL, Ll = short hair; ll = long hair. A breeder mates a black, long-haired guinea pig with a bbll guinea pig. What are the possible answers and what outcomes will they produce? Show your work.

One possible answer to the breeder's question: Bb → The cross would produce roughly equal numbers of black and white offspring. The other possible answer to the breeder's question: BB → The cross would produce all black offspring.

What observations suggest that in environments containing antibiotics, M. tuberculosis individuals experience differential reproductive success based on their degree of resistance?

Over time, the frequency of resistant individuals increases when patients take antibiotics.

If a parent's genotype is PpTtLl, what are the gamete genotypes it produces under the hypothesis of independent assortment?

PTL, PTl, pTL, pTl, ptL, ptl, PtL, Ptl (in equal proportions)

What does it mean to say that "homologs synapse?"

Pairs of homologous chromosomes physically come together.

What does the p in "p-value" represent?

Probability (of getting the observed result, just by chance)

When sample size increases ...

Rare events have less influence on the estimate of the effect (e.g., the average or slope).

Hormones called angiogenesis inhibitors (here, AI's) slow the rate at which blood vessels grow into tissues. A tumor is a growing lump of tissue. It cannot grow beyond a certain size unless blood vessels grow into it. This suggests the hypothesis that AI might be useful anti-cancer drugs. Design an experiment to test this hypothesis. You have laboratory mice into which you can implant tumors, a supply of AIs, and an unlimited supply of cages, water, and mouse chow. What are your treatment groups?

Several dozen mice per group, implanted with tumors, then injected with a dose of AI or a dose of drug-free saltwater.

Hormones called angiogenesis inhibitors (here, AI's) slow the rate at which blood vessels grow into tissues. A tumor is a growing lump of tissue. It cannot grow beyond a certain size unless blood vessels grow into it. This suggests the hypothesis that AI might be useful anti-cancer drugs. Design an experiment to test this hypothesis. You have laboratory mice into which you can implant tumors, a supply of AIs, and an unlimited supply of cages, water, and mouse chow. What is your dependent (response) variable?

Size of the tumor 1 month after implantation and treatment.

What observations suggest that in M. tuberculosis, antibiotic resistance is a trait with heritable variation?

Some individuals are more resistant to antibiotics than others, and pass this trait on to offspring.

In August of 2020, D. R. Boulware and colleagues published a research report in the New England Journal of Medicine. The scientists had studied ~800 volunteers who had no symptoms of illness, but who had recently been exposed, at home or at work, to someone infected with SARS-CoV-2, the virus that causesCovid-19. They assigned the volunteers at random to two groups. One group received pills containing the drug hydroxycholoroquine; the other group got a placebo (pills containing no medicine). Two weeks later, the scientists tested the volunteers to see if they were infected with the virus. The graph summarizes the results. The vertical black lines at the tops of the bars represent ± 1 standard error. In ONE sentence, what does a comparison of the standard error bars indicate?

The standard error bars overlap which suggests, as a rule of thumb, that there is not sufficient evidence to reject the null hypothesis that the rate of infection is the same in both groups

C. elegans is a tiny worm that lives in soil. Pei-Yin Shih and colleagues studied C. elegans from Bristol and Hawaii. They exposed worms, in groups, to a dangerous concentration of arsenic. Look at the data for the worms from Bristol versus Hawaii. In ONE or TWO sentences, what is the pattern in the data?

The worms from Hawaii show higher arsenic resistance, on average, versus the worms from Bristol.

Hormones called angiogenesis inhibitors (here, AI's) slow the rate at which blood vessels grow into tissues. A tumor is a growing lump of tissue. It cannot grow beyond a certain size unless blood vessels grow into it. This suggests the hypothesis that AI might be useful anti-cancer drugs. Design an experiment to test this hypothesis. You have laboratory mice into which you can implant tumors, a supply of AIs, and an unlimited supply of cages, water, and mouse chow. Name another variable you will control. In ONE sentence, explain how.

There are many possibilities: Sex of the mice, controlled by making sure each group is half females and half males; Emotional stress experienced by the mice, controlled by making sure all mice are kept in clean cages, with companionship, space, a stimulating environment, and the opportunity to exercise; Age of the mice, controlled by enrolling them all when they are, say, six weeks old; etc.

Suppose we run a statistical test, and learn that p = 0.01. What does this mean?

There is a 1 in 100 chance of observing a pattern this extreme if the null hypothesis is correct.

If we want to compare the scores of 1st-year and 2nd-year students using a statistical test, our null hypothesis will be...

There is no difference in exam performance between students in year 1 and 2.

If "dependent assortment" occurs, how do alleles of different genes behave?

They "stick together" (they are transmitted together--as if they were a single gene).

What does it mean to say that two chromosomes are homologous?

They are the same size and contain the same genes.

Why don't alleles from linked genes assort independently, if no crossing over occurs?

They are transmitted together (on the same chromosome), instead of being transmitted independently of each other.

Why do alleles from linked genes assort independently, if crossing over DOES occur?

They end up on different chromosomes, so are then transmitted independently of each other.

Typological thinking and typological thinking + the scale of nature are variants of the theory of special creation. The geologic record and radiometric dating are inconsistent with common versions of the theory of special creation. Why?

They support the hypothesis that Earth itself and life on Earth are ancient.

Genetic, developmental, and structural homologies are inconsistent with the theory of special creation. Why?

They support the hypothesis that species are related by common ancestry--meaning that they were not created independently of each other.

The "law of succession," the presence of vestigial traits, and the fact of extinction are all inconsistent with the theory of special creation. Why?

They support the hypothesis that the characteristics of species--and the collection of species present--has changed through time.

What is the relationship between the Great Chain of Being and the process component of Lamarck's theory of evolution?

Under Lamarkian evolution, species move up the Great Chain of Being over time.