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50 terms

biology exam 2 questions

Two true-breeding plants are cross-fertilized. Their offspring are then cross-fertilized. What is the name given to this last offspring generation?
F2 generation
DdEe pea plants can produce _____ type(s) of gametes, but a ddee plant can produce _____ type(s) of gametes.
four ... one
Three characteristics assort independently in one species of insect: Red eyes (R) are dominant to black eyes (r). Blue wings (B) are dominant to white wings (b). Green bodies (G) are dominant to yellow bodies (g). A cross is made between two heterozygous insects (RrBbGg). What is the probability that the offspring will be homozygous dominant for all three characteristics?
Many genetic disorders can be detected before birth. Procedures include _____, which is noninvasive, or _____, which allows the chromosomes of the fetus to be examined. Alternatively, maternal blood samples can be taken and tested for _____ .
ultrasound imaging ... chorionic villus sampling ... AFP
After crossing a true-breeding red-flowered snapdragon with a true-breeding white-flowered one, you note that all of your F1 population are pink. This is because _____.
red and white show incomplete dominance
Two parents of mixed ethnicity have twins, one of which is born white and one of which is born black. This is because of _____.
the polygenic nature of skin color genes
Linked genes are inherited together. This is because linked genes _____.
are on the same chromosome
The frequency at which crossing over occurs between two linked genes depends on _____.
how far apart the genes are on the chromosome
Gene Q is an X-linked dominant allele in crustaceans that controls eye color. A cross is performed between two crustaceans: a green-eyed male (XQY) and a green-eyed female (X QX q). What percentage of the offspring have green eyes?
A woman and her male partner have normal color vision. However, her father and her first son are color-blind. What is her genotype? Use C as the gene for color blindness.
Which of the following statements best defines recombinant DNA technology?
combining genes from different sources
Scientists who wish to clone genes of interest into bacterial plasmids utilize _____, which cuts the target and vector DNA at specific sites. Then _____ is used to form covalent bonds between the resulting fragments to complete the recombinant DNA molecule.
a restriction enzyme ... DNA ligase
The fragments produced by most restriction enzymes have _____.
complementary single-stranded ends
A genomic library is _____.
a collection of cloned DNA fragments from an organism's genome
Insulin, for the treatment of diabetes in humans, is now secreted by _____.
Golden rice has been genetically engineered. It differs from other rice varieties because it contains genes that will produce _____.
DNA moves through a gel toward the positive electrode when an electric charge is applied. What property of DNA allows this to occur?
DNA has a negative charge.
To identify an individual involved in a crime, criminologists analyze DNA from a suspect's blood and compare the _____ to samples found at the crime scene.
DNA profile
What does the term restriction fragment length polymorphism mean?
fragments of DNA that can produce different patterns in different individuals
The individuals working on the Human Genome Project (HGP) were attempting to _____.
map all the human genes and determine the nucleotide sequence of the entire human genome
What broad set of ideas was established by the work of Lamarck, Lyell, and Darwin?
Earth and its life are ancient and ever-changing; fossils document the evolution of life-forms over time.
list of assumptions part of Charles Darwin's theory of natural selection
1. Organisms vary in heritable ways.
2. Some traits improve the survival and reproduction of individuals who possess them.
3. Populations produce more offspring than their environment can support, so individual organisms must compete for limited resources.
4. Earth and its life are very old.
Which best describes the fossil record?
The fossil record is the highly ordered sequence in which fossils are found in layers of sedimentary rock.
The forelimbs of humans, cats, and bats have a number of detailed similarities in their construction. What best explains these similarities?
The forelimbs are similar because all of these organisms inherited the basic forelimb design from a common ancestor.
Variation among _____ within a _____ makes microevolution possible.
individuals ... population
According to the Hardy-Weinberg theorem, the frequencies of alleles in a population will remain constant if _____ is the only process that affects the gene pool.
sexual reproduction
A population of small fish live in a lake with a sandy bottom. The major predator of these fish is a wading bird that hunts by sight. Most of the fish are light sandy brown, but about 10% are mottled. The color pattern is heritable. A construction company dumps a load of gravel in the bottom of the lake, giving it a mottled appearance. Which of these statements presents the most accurate prediction?
The proportion of mottled fish will increase over time.
Which best describes how an organism's Darwinian fitness is measured?
the organism's reproductive success relative to other individuals in the same population
Blue poppies native to China are grown at a plant-breeding center in California, where those with the thickest leaves survive and reproduce best in the drier climate. This evolutionary adaptation of the poppies to their new environment is due to _____.
directional selection
Certain bacterial strains have traits that allow them to resist the effects of antibiotic drugs. How do the resistance traits arise, and under what circumstances will the resistance traits be most common?
The resistance traits are produced by chance mutations and are present to varying degrees in most bacterial populations. Resistance traits will be most prevalent, however, in bacteria that are chronically exposed to antibiotic drugs.
Charles Darwin's main focus was on the gradual process of adaptation within populations. This form of change _____.
cannot account for increases in species diversity over time
Two animals are considered members of different biological species if they _____.
are male and female, but cannot interbreed
Often, the morphological species concept is used to define and describe species. Why?
This is the most convenient way of identifying species, and it is one of the few ways to identify fossil or asexual species.
The following options are all reproductive barriers. Which one is an example of a prezygotic barrier in which the two different species do mate?
Two dragonfly species regularly mate, but their gametes are incompatible.
Which of these is an example of temporal isolation?
One species is diurnal (day active) and mates at high noon; the other is nocturnal (night active) and mates at midnight.
What is the first step in allopatric speciation?
geographic isolation
Sympatric speciation is _____.
the appearance of a new species in the same area as the parent population
_____ generated many key crop plant species in the past, and continues to be an important method for plant geneticists today.
Sympatric speciation by polyploidy
The evolution of numerous ecologically diverse species in a relatively short time period, such as Darwin's finches, from a single ancestor is called _____.
adaptive radiation
According to the _____ model, evolution occurs in spurts: Species evolve relatively rapidly and then remain unchanged for long periods.
punctuated equilibrium
Which combination of features would occur in a typical animal?
multicellular, heterotrophic, obtain food by ingestion, lack cell walls
All animals can probably trace their lineage to a common ancestor that lived in the _____.
mid to late Precambrian (1 billion years ago or less)
If an organism is a protostome, what else can you conclude about its body plan?
It is bilaterally symmetrical and has three tissue layers.
Among animals, sponges are unique in that they _____.
lack true tissues
Which phyla both possess a gastrovascular cavity that has only one opening?
Cnidaria and Platyhelminthes
In the ocean, you find an organism with a hard exoskeleton and jointed legs. It is _____.
an arthropod, and probably a crustacean
Which feature of insects has promoted their diversification and evolutionary success?
Insects have repeated modular segments that develop independently of each other. Thus, insects have been able to evolve appendages that are specialized for diverse functions.
Which of the following is evidence that the extant phylum most closely related to chordates is Echinodermata?
They are both deuterostomes.
Which characteristic is unique to Chordata (it is a diagnostic feature) and is evident at some stage of the life cycle in all chordates?
Compared to fruit flies, humans have _____.
a similar number of genes and similar types of genes that build the body parts and organs; however, the DNA sequences that regulate our gene expression patterns are very different