BIO 180 WI 17 Reading Quiz Questions

In a population of diploid organisms, the frequencies of alleles for a gene are 0.1 "A", and 0.9 "a". If mating is random, and the alleles are neutral (they have no affect on fitness), what is the probability of two individuals mating and producing an offspring that is heterozygous (Aa)?

0.18

How many DNA double-helixes make up an unreplicated chromosome?

1

If I flip a fair coin and roll a fair six-sided die, what is the probability that I get a heads and a 2?

1/12

If I roll a fair six-sided die, what is the probability that I get a 1 or a 6?

1/3

If $100 is graphed on a logarithmic scale, it is 2 "log" dollars (because 10^2 = 100). The US government spent about $30 billion on science in 2015. How much is this on a logarithmic scale?

10.5 "log" dollars

How many DNA double-helixes make up a replicated chromosome?

2

How many DNA double-helixes are present in a synapsed pair of homologous chromosomes?

4

What is the difference between a hypothesis and a prediction?

A hypothesis is an idea; a prediction is something that follows from a hypothesis and that you can measure

What is genetic recombination?

A new combination of alleles on the same chromosome.

What is a genetic locus?

A particular position on a chromosome.

In biology (and in science in general), what does the word theory mean?

A proposed explanation for a general phenomenon--a hypothesis relevant to a big question.

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--the green-tipped pages (tan colored pages in the 5th edition) in the back of the book.)

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.

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

What is cytokinesis?

Cell division (usually follows mitosis and meiosis)

How does outcrossing create genetic variation?

Chromosomes from different individuals combine to form a new diploid genotype (offspring).

Which of the following happens during interphase, before mitosis or meiosis? 1. The nuclear envelope breaks down (this has to happen so that spindle fibers can contact the chromosomes). 2. The spindle apparatus forms. 3. Chromosomes condense (so that they can move without getting tangled up). 4. Chromosomes replicate (each consists of two sister chromatids).

Chromosomes replicate (each consists of two sister chromatids).

What is double and helical about the double helix?

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

How does crossing over and recombination create genetic variation?

Each chromosome has a unique mix of segments from the maternal and paternal chromosome.

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 always correct? 1. F1s are heterozygous; F2s are homozygous recessive, homozygous dominant, and heterozygous 2. F1s are the first generation in an experimental cross; F2s are the second. 3. There are more individuals in the F2 generation than the F1. 4. F1s have a 3:1 ratio of phenotypes; F2s have a 9:3:3:1 ratio.

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

What does it mean to say that an individual outcrosses?

Gametes from different individuals combine to produce offspring.

How does independent assortment create genetic variation?

Gametes get a random assortment of maternal and paternal chromosomes.

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.

What was important about the experimental design for Pasteur's flask experiment?

He compared results from two experimental setups which differed only in the type of flask in which the nutrient broth was placed

Which of the following characterizes a recessive allele? 1. Heterozygotes don't show its phenotype. 2. If environmental conditions vary, its phenotype varies in response. 3. It is the allele that confers lower fitness. 4. It is the least common allele in the population.

Heterozygotes don't show its phenotype.

Which of the following characterizes a dominant allele? 1. Heterozygotes show its phenotype. 2. It is the allele that confers highest fitness. 3. It is the most common allele in the population. 4. Even if environmental conditions vary, its phenotype does not.

Heterozygotes show its phenotype.

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

Histogram

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.

Why is it important that they assigned trees to the infected versus uninfected groups at random?

If assignment was not random, the result could be do to something other than the difference in infection

Which of the following is a prediction based on the cell theory that all organisms are made of cells, and all cells come from preexisting cells? 1. Cells arise spontaneously from nonliving material 2. If you boil nutrient broth and place it in an air-tight flask, cells will appear in the broth 3. Cells are produced only from pre-existing cells 4. If you boil nutrient broth and place it in an air-tight flask, no cells will appear in the broth

If you boil nutrient broth and place it in an air-tight flask, no cells will appear in the broth

When homologs synapse in prophase of meiosis I, crossing over occurs in both pairs of non-sister chromatids, but at different locations. In terms of generating genetic variation, why is this significant?

In gametes, EVERY chromosome has a unique combination of paternal and maternal alleles.

Which of the following is the most important difference between the events of prophase in mitosis versus meiosis I?1. In mitosis, sister chromatids separate. 2. In meiosis I, homologs synapse. 3. In mitosis, crossing over occurs between sister chromatids. 4. In mitosis, the nuclear envelope breaks down and the spindle fiber forms.

In meiosis I, homologs synapse.

The top graph in Figure 22.13 (5th edition: 25.16) 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.

For the purposes of this course, which of the following is the best working definition of mRNA? 1. Information carrier 2. Machinery that performs a function in the cell 3. Information translator 4. Information archive

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.

To find a gene, you have to associate a phenotype with a genotype (e.g. all individuals with white flowers have a certain allele). It is MUCH harder to find genes that are involved in polygenic traits than it is to find the genes responsible for discrete traits. Why?

It's harder to find one of the many genes involved in a polygenic trait vs. the only gene involved in a discrete trait..

For the purposes of this course, which of the following is the best working definition of a protein? 1. Information archive 2. Machinery that performs a function in the cell 3. Information carrier 4. Information translator

Machinery that performs a function in the cell

How is polygenic inheritance defined?

Many genes contribute to the phenotype--not just one or two.

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.

How is it possible for offspring to have different phenotypes from their parent, even when 1) self-fertilization occurs, 2) there is no crossing over, and 3) no mutation occurs?

Offspring can be homozygous at genes where parents are heterozygous.

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

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

Pairs of homologous chromosomes physically come together.

How do biologists test their ideas about the natural world?

Scientists make predictions based on hypotheses they have developed, and then design experiments to test those predictions

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.

What is the pattern component of the theory of special creation?

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.

What is the process component of the theory of special creation?

Species were created, instantaneously and independently of each other, by God.

In biology, what does the word fitness mean?

The ability to survive and reproduce.

Monozygotic twins occur when a fertilized egg undergoes mitosis, and the two cells that result become separated and develop independently. What is the genetic relationship between the two offspring?

The are genetically identical (clones).

In the test above, what was our test statistic?

The average difference in exam score between 1st and 2nd-year students.

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

The behavior of chromosomes during meiosis I.

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.

Look at the middle graph in Figure 22.14 (5th edition: 25.17). Why didn't beak size continue to increase, after the 1978 drought?

The environment changed, and large-beaked individuals no longer had highest fitness.

The remaining questions refer to this situation: Researchers do an experiment to test the hypothesis that Douglas fir trees put more resources into reproduction when they are infected with a fungus that causes a fatal disease. They establish study plots in a group of 50-year-old Douglas fir where the disease is not present. At random, they infect half the trees with the disease-causing fungus. Then they measure how many cones and seeds are produced by infected versus uninfected trees. What prediction follows from the hypothesis?

The infected trees will produce more seeds than uninfected trees

Which of the following is the correct definition of haploid number? 1. The number of different types of chromosomes present. 2. The number of each type of chromosome present. 3. Having unreplicated chromosomes (one chromosome—not two chromatids) 4. The total number of chromosomes present.

The number of different types of chromosomes present.

Which of the following is the correct definition of ploidy? 1. The number of each type of chromosome present. 2. Having replicated chromosomes (two chromatids—not one chromosome) 3. The total number of chromosomes present. 4. number of different types of chromosomes present.

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.

On average, 1st-year students score 4.3 points higher than 2nd-year students. What do we use to decide if this difference is significant?

The probability of getting a difference 4.3 points, or greater, if exam performance is not affected by year in school.

What does a ratio report?

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

Name one variable that is held constant between the two treatment groups.

The species of tree

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

There is a 1 in 100 chance of getting data 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.

In response to studies on "evolution in action"--the observation that hundreds of populations have been observed to change in response to changes in their environments--proponents of the theory of special creation either 1) ignore the data, or 2) argue that they are irrelevant to the question of how large-scale differences among species arose (e.g. how bats came to have wings). As a scientist, how would you evaluate these objections?

There is no logical reason to suspect that the process that lead to changes being observed today didn't operate in the past, and that they would not lead to large changes over long time periods.

If the hypothesis is wrong, and being infected with the fungus has no impact at all on reproduction, what should they observe?

There will be no difference in the number of seeds produced by infected versus uninfected seeds

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).

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.

The geologic record and radiometric dating are inconsistent with 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.

Why is it important to do the experiment in the same group of same-aged trees?

To eliminate the possibility that the results are due to differences in age, soil, moisture, or other relevant variables

Why is it important to perform multiple trials in an experiment -- meaning that you include many test individuals or samples?

To make it more likely that the results are not due to a few unusual individuals or circumstances

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.

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."

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.

In many cases, the theory of evolution provides a logical explanation for observations that are puzzling under the theory of special creation. Under special creation, why is the presence of vestigial traits puzzling?

Why would an intelligent designer create traits that have reduced or no function?

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 the U, 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 Rand B genes). Suppose a male carries an X chromosome with the R allele and the b allele. How would you write his genotype? (Note: In the answer options, ^ means superscript)

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.

In a statistical test, by increasing the sample size...

You can detect a smaller departure from the null hypothesis.

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? 1. strings of pop beads (each bead is a gene) 2. pipe cleaners (each pipe cleaner is one chromosome) 3. a six-pack of soda with the cans held together by plastic rings 4. string or twine (each length of string is one chromosome)

strings of pop beads (each bead is a gene)

In DNA, the base called adenine binds to which other base?

thymine (A-T)