Test 2 (chap 6-10) Flashcards by Hannah Hornaday

Which statement about DNA is false

Humans lack DNA in their brain cells

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What was so groundbreaking about the “double” part of the double-helix molecule

It suggested how genetic information could be copied and inherited

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Which nucleotide bases are present in equal amounts in DNA

guanine and cytosine, adenine and thymine

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Genes are borne on structures called

chromosomes

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Alternate versions of a gene are called ________. They can code for different ________ of the same character

alleles; traits

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The highest percentage of non-coding DNA is found in

eukaryotes (with the exception of yeasts)

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Which statement correctly describes the locations of transcription and translation within a eukaryotic cell

DNA is transcribed in the nucleus, and then the mRNA transcript is transported to the cytosol to be translated into protein

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difference between mRNA and DNA is

mRNA can move throughout the cell, whereas DNA stays in the nucleus

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When a triplet of bases in the coding sequence of DNA is TAG, the corresponding codon for the mRNA transcribed from it is

AUC

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During translation, the first amino acid in the protein sequence is always

methionine

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Which statement about frameshift mutations is false

Frameshift mutations involve substitutions of nucleotides

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Which of the following is a true statement about biotechnology

Biotechnology can create harmful environmental impacts

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Which of these would be considered a transgenic organism

a rat with rabbit hemoglobin genes

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A group of scientists is attempting to remove a gene from bacterial cells that confers resistance to the common antibiotic, penicillin. Which tool would be the most precise and efficient for this task

using CRISPR to find and cut a specific sequence of bacterial DNA

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Which statement about biotechnology is true

The majority of corn, cotton, and soybeans grown in the United States is genetically modified

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Which statement about genetically modified foods and animals is true

Organisms that we want to kill may become invincible due to the use of GMOs

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Some athletes illegally use recombinant human ___________ to improve their athletic performance because it increases the oxygen-carrying capacity of the blood

erythropoietin (EPO)

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The technique in which a non-functioning gene is replaced by a functioning gene in somatic cells is called gene

therapy

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The pattern of bands in a DNA fingerprint represents the

presence of fragments of DNA with variable lengths

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Bacteria divide by a type of ______________________ called ______________________

asexual reproduction; binary fission

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Which statement about the eukaryotic cell cycle is true

A cell can remain in Gap 1 for an hour, a day, a week, or a year.

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Which assessment occurs at the G2/M checkpoint

DNA is checked for damage before entering mitosis

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The process of DNA replication occurs in two steps: 1) __________ of the double-stranded DNA molecule and 2) __________ of the new complementary strands

unwinding and separation; reconstruction and elongation

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The single purpose of mitotic cell division is

generation of new genetically identical cells

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A cell divides by mitosis. The result is

two identical daughter cells

mitotic cell cycle phase order

1. interphase 2. prophase 3. metaphase 4. anaphase 5. telophase

detailed chronological order of mitotic cell cycle

Chromosomes line up at the center of the cell, the centromeres separate, the chromosomes move toward opposite poles, two daughter nuclei are formed, and the cytoplasm is divided

Which of these is a feature of cancer cells

Cancer cells’ membranes often have reduced adhesiveness

Which statement about the similarities and differences between chemotherapy and radiation therapy as cancer treatments is true

In radiation therapy, all tissue may be harmed, whereas in chemotherapy, the rate at which healthy cells divide may be reduced

In humans, the diploid number equals

When a male donkey is bred with a female horse, the offspring produced is a mule, which is healthy but sterile. Karyotyping experiments have revealed that horses and donkeys have different numbers of chromosomes: 64 for horses, and 62 for donkeys. Therefore, the mule has 63 chromosomes. Knowing this, what is the best explanation for the inability of mules to produce offspring

Proper pairing of homologues is impossible during meiosis I

The defining feature of males in sexually reproducing species is the sex with

motile gametes

Recombination, or crossing over, is a process by which

pieces of homologous chromosomes are exchanged

Which statement about sexual reproduction is true

Organisms make themselves vulnerable to disease, predation, and other dangers during mating and reproduction

Which statement is true regarding human sex chromosomes

On average, half of a man’s sperm carry an X chromosome, and half carry a Y.

An abnormal number of chromosomes can occur due to one particular erroneous meiotic event called

nondisjunction (chromosomes do not separate)

Which of the following human sex chromosome genotypes is not possible

A man who is aware that he is a silent carrier of the FMO3 “fish odor syndrome” gene has children with a woman who is “normal.” Which statement would best explain how a child born from these parents could have fish odor syndrome

The mother is also a silent carrier of the defective FMO3 allele

Which of these is a single-gene trait

fur length in cats

What was the most important scientific advance gained from Gregor Mendel’s experiments with pea plants

We learned that many traits are inherited in discrete units and are not the result of blending

If a true-breeding, blue-flowered plant was crossed with a true-breeding, white-flowered plant, what phenotypic ratio would we observe in the progeny resulting from this cross? Assume that the white-flowered trait is completely dominant

100% white

How can two pea plants that have different genotypes for seed color be identical in phenotype

One of the two plants could be homozygous for the dominant allele, whereas the other could be heterozygous

In certain plants, red flowers are dominant to white flowers. If a heterozygous plant is crossed with a homozygous red-flowered plant, what is the probability that the offspring will be white-flowered

In pea plants, the allele for purple flower color is dominant to the allele for white flower color. If you performed a test-cross to determine the genotype of a purple-flowered plant, what would you expect the phenotypic ratio of purple-flowered to white-flowered progeny to be if the plant is homozygous? What if the plant is heterozygous

If the purple-flowered plant is homozygous, then the progeny would all have purple flowers. If the purple-flowered plant is heterozygous, then the progeny would have purple to white flowers in a 1:1 ratio

Phenylketonuria (PKU) is an autosomal recessive condition requiring two copies of an abnormal gene. A man with PKU and a woman without PKU have a son named Peter, who does not have PKU. Peter is curious about whether his mother is a carrier for PKU. Which fact would allow him to know

Peter’s maternal grandfather has PKU

The difference between incomplete dominance and codominance is that

in incomplete dominance, the trait under observation is produced by the combination of multiple alleles, whereas in codominance, the trait is produced by a single allele

In the ABO blood type system in humans, there are _________ different alleles, _________ different phenotypes, and _________ different genotypes

three; four; six

In the case of Mendel’s peas, a single gene determined the height of the plant. However, in humans, adult height is influenced by many genes. A trait such as human height is said to be

polygenic

The SRY gene, found on the Y chromosome, causes fetal gonads to develop as testes, as well as many other developmental changes. The SRY gene shows both

sex linkage and pleiotropy

Your father’s mother was a heterozygous carrier of an X-linked trait. If you are a male, what are the chances that you will inherit this X-linked trait by direct descent from your paternal grandmother

Phenotypes are generally a product of

the genotype in combination with the environment

We say that genes are linked when they

are located near each other on a single chromosome

what is the maximum number of hours an individual fruit fly could survive without food after an experimenter has selected for starvation resistance on this population over thousands of generations

Theoretically, there is no maximum number of hours

Which statement is true about charles lyell

Charles Lyell argued that geological forces had gradually shaped the Earth and continued to do so

While traveling around the world on the HMS Beagle, Charles Darwin made which of the following observations

Island species of finch closely resembled mainland finches

Darwin’s observations while traveling on the Beagle helped him develop which theory

Species might change over time

If evolution has occurred

the allele frequencies in a population have changed

Most mutations are

random with respect to the environmental needs of the organism in which the mutation takes place

Which statement about genetic drift is true

Genetic drift can obscure the deterministic process of selection

The migration of reproductive individuals between populations results in a movement of alleles called

gene flow

Natural selection can only act on traits that

are heritable

Choose the statement that correctly describes the changes in genetic variability from the four agents of evolution

Mutation and migration lead to increased variation, whereas genetic drift and natural selection decrease variation over time

What is the best measure of an organism’s fitness

the number of fertile offspring it produces

Which of these statements about adaptation is true

Natural selection can produce adaptation; however, it does not necessarily lead to organisms perfectly adapted to their environment

A population’s environment changes rapidly. In these situations

natural selection may be too slow to adapt the organisms in a population to such a moving target

Which statement best describes the difference between natural and artificial selection

Natural selection can act without the input of humans; artificial selection requires some human input

A “U-shaped” distribution for a trait, with high frequencies of individuals who exhibit extreme values for a trait (and few individuals with medium values), is most likely to be caused by ______ selection

disruptive

A breeder of thoroughbreds selects only the fastest horses for breeding stock. This is an example of artificial ____________ selection

directional

Human birth weight is a classic example of the results of

stabilizing selection

Which statement describes a limitation of using the fossil record to study evolution

Fossils only form under a very specific and rare set of environmental conditions

A radioactive isotope has a half-life of 5,000 years. A rock originally contained 16 grams of radioactive isotope and now contains 4 grams. Approximately how many years old is the rock

10,000 years

The study of the distribution patterns of living organisms around the world is called

biogeography

Anatomical homology in vertebrate forelimbs is considered to be evidence for evolution because

similarities among vertebrate forelimbs suggest that they evolved from a common ancestor

The longer that two species have been evolving on their own, the

greater the genetic differences that accumulate between them