Test 2 (chap 6-10) Flashcards
Which statement about DNA is false
Humans lack DNA in their brain cells
What was so groundbreaking about the “double” part of the double-helix molecule
It suggested how genetic information could be copied and inherited
Which nucleotide bases are present in equal amounts in DNA
guanine and cytosine, adenine and thymine
Genes are borne on structures called
chromosomes
Alternate versions of a gene are called ________. They can code for different ________ of the same character
alleles; traits
The highest percentage of non-coding DNA is found in
eukaryotes (with the exception of yeasts)
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
difference between mRNA and DNA is
mRNA can move throughout the cell, whereas DNA stays in the nucleus
When a triplet of bases in the coding sequence of DNA is TAG, the corresponding codon for the mRNA transcribed from it is
AUC
During translation, the first amino acid in the protein sequence is always
methionine
Which statement about frameshift mutations is false
Frameshift mutations involve substitutions of nucleotides
Which of the following is a true statement about biotechnology
Biotechnology can create harmful environmental impacts
Which of these would be considered a transgenic organism
a rat with rabbit hemoglobin genes
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
Which statement about biotechnology is true
The majority of corn, cotton, and soybeans grown in the United States is genetically modified
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
Some athletes illegally use recombinant human ___________ to improve their athletic performance because it increases the oxygen-carrying capacity of the blood
erythropoietin (EPO)
The technique in which a non-functioning gene is replaced by a functioning gene in somatic cells is called gene
therapy
The pattern of bands in a DNA fingerprint represents the
presence of fragments of DNA with variable lengths
Bacteria divide by a type of ______________________ called ______________________
asexual reproduction; binary fission
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.
Which assessment occurs at the G2/M checkpoint
DNA is checked for damage before entering mitosis
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
The single purpose of mitotic cell division is
generation of new genetically identical cells
A cell divides by mitosis. The result is
two identical daughter cells
mitotic cell cycle phase order
- 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
46
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
YY
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
0%
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
0%
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
