Cells
As human red blood cells mature, they lose their nuclei. As a result of this loss, which process would be impossible for mature red blood cells to carry out? (1) excretion (2) reproduction (3) respiration (4) transport
(2) reproduction
Humans are able to positively or negatively affect their environment in many ways. Which statement accurately describes one of these possible effects? (1) A positive environmental effect is that burning fossil fuels to generate electricity reduces carbon dioxide levels in the atmosphere. (2) A positive environmental effect is the cutting of trees in rain forests to provide large quantities of lumber to build homes for the increasing world population. (3) A negative environmental effect is that industrialization provides many jobs and helps the economy grow. (4) A negative environmental effect is that unregulated fishing in the ocean can disrupt the interactions between organisms in existing food webs.
(4) A negative environmental effect is that unregulated fishing in the ocean can disrupt the interactions between organisms in existing food webs.
A scientist at a large natural history museum has a collection of fossils that were found throughout the world. Only a few of the fossils represent species that are still alive on Earth today. One reason for this is that (1) most of the species that have ever lived on Earth are alive today (2) most of the species that have ever lived on Earth are extinct (3) fossils of only extinct species have been found (4) species alive today will not form any fossils for future discovery by scientists
(2) most of the species that have ever lived on Earth are extinct
Sexually reproduced offspring have traits similar to their parents because they receive (1) all of the proteins from each parent (2) some of the proteins from both parents (3) all of the genes present in both parents (4) some of the genes present in each parent
(4) some of the genes present in each parent
To clone a mammal, a cloned embryo is often put into an adult female of the same species to continue internal development. The structure in which the embryo will develop is the (1) ovary (2) uterus (3) placenta (4) egg
(2) uterus
Which statement best describes the interactions between the structures found within a single-celled organism? (1) They allow the organism to maintain homeostasis. (2) They prevent homeostasis from damaging the cell. (3) They must act independently of each other and prevent homeostasis. (4) They carry out the same life
(1) They allow the organism to maintain homeostasis.
In New York State, it is common for farmers to plant large fields of one crop. A negative outcome of this practice is that (1) the corn will interbreed with weeds in the area (2) new predators will be introduced into the ecosystem (3) the stability of the ecosystem will be reduced (4) new species of insect-resistant corn will evolve
(3) the stability of the ecosystem will be reduced
Studying fossils provides evidence for evolution because fossils (1) take a long time to form (2) can show patterns of biological change over time (3) always contain complete DNA sequences (4) found in the same area are usually closely related to each other
(2) can show patterns of biological change over time
Hammerhead sharks are unlike most other shark species. Nearly all shark species either lay eggs or give birth to live young after their eggs hatch internally. Hammerhead sharks form a placenta, a structure more commonly found in mammals, such as humans. One role of the placenta in the development of offspring is normally to (1) produce blood cells (3) produce gametes (2) provide milk (4) transfer nutrients
(4) transfer nutrients
The organic compounds that scientists use to cut, copy, and move segments of DNA are (1) carbohydrates (2) hormones (3) enzymes (4) starches
(3) enzymes
When cells reproduce abnormally, it could be a sign of (1) an immune response (2) cancerous cell growth (3) dynamic equilibrium (4) a cellular adaptation
(2) cancerous cell growth
By measuring the colors of light refl ected by different tree species in a forest, scientists can determine the amount of biodiversity present in different areas. Maintaining biodiversity is important because it (1) reduces the carrying capacity of a forest ecosystem (2) guarantees that all species within a forest ecosystem will survive (3) increases the number of predators that control the population size of prey (4) ensures the availability of a variety of genetic material
(4) ensures the availability of a variety of genetic material
Farmers have been planting crops that express an insecticide gene, so that when pests consume these crops, the pests are poisoned. Unfortunately, since these plants were introduced in 1996, growing numbers of insect pests have developed resistance to the insecticide. The process that led to the insect resistance can best be explained by (1) ecological succession (2) selective breeding (3) asexual reproduction (4) natural selection
(4) natural selection
A response of a normally functioning immune system that can be harmful is (1) being infected by the flu virus (2) rejecting an organ transplant (3) recognizing chemical signals (4) fighting off a bacterial infection
(2) rejecting an organ transplant
Sheets of skin are grown in a culture in order to replace the skin of victims with severe burns or frostbite. Undamaged skin cells are obtained from the victim, put in a Petri dish with the proper growth materials, and incubated. These new skin cells form as a result of (1) meiotic cell division (2) mitotic cell division (3) sexual reproduction (4) gene recombination
(2) mitotic cell division
A biotechnology tool, known as CRISPR-Cas9, allows scientists to precisely edit genes. In order to edit genes, CRISPR-Cas9 must be able to (1) alter the base sequence of DNA (2) prevent cells from differentiating (3) block cell receptors from receiving signals (4) change the rate at which a cell uses ATP
(1) alter the base sequence of DNA
Large numbers of white-tailed deer on Long Island are infested with ticks that transmit Lyme disease to other mammals. One attempt to control reproduction in these ticks has been the release of large numbers of sterilized male ticks. When compared to using pesticides, this method to control ticks would (1) cause more environmental pollution (2) lead to a decrease in the deer population (3) be less likely to harm the environment (4) result in an increase in the tick population
(3) be less likely to harm the environment
Scientists at Penn State have sequenced the DNA of the extinct woolly mammoth. The data suggested that the woolly mammoth was more closely related to present-day elephants than previously believed. Which statement could account for the similarities between the woolly mammoth and present-day elephants? (1) Common gene mutations were caused by agents such as industrial chemicals and radiation. (2) Present-day species developed from earlier, different species. (3) Selective breeding results in offspring better able to survive. (4) Both animals have identical genetic information.
(2) Present-day species developed from earlier, different species.
Which sequence best represents the correct order of events in the formation of a sexually reproduced individual? (1) embryo → zygote → gamete → fetus (2) zygote → embryo → fetus → gamete (3) gametes → embryo → fetus → zygote (4) gametes → zygote → embryo → fetus
(4) gametes → zygote → embryo → fetus
PCR, Polymerase Chain Reaction, is a method for carrying out DNA replication. In order to perform this technique, a scientist would need (1) a DNA template, ATP, and 20 different amino acid subunits (2) enzymes, several types of simple sugars, and starch molecules (3) a DNA template, enzymes, and subunits with A, G, T, and C bases (4) enzymes, specifi c receptor molecules, and several hormones
(3) a DNA template, enzymes, and subunits with A, G, T, and C bases
The process of differentiation is best described as the (1) production of a genetically identical copy of an organism (2) change in shape of a protein due to high temperatures (3) process by which cells specialize and develop into a specific type of cell (4) process in which genes are made and transferred into other organisms
(3) process by which cells specialize and develop into a specific type of cell
Direct harvesting occurs when (1) pine trees are cut from a forest for use as lumber (2) corn is planted in a newly plowed fi eld (3) zebra mussels are accidentally imported to the Great Lakes (4) roots of plants continually take in water
(1) pine trees are cut from a forest for use as lumber
After a lake dried up during a severe drought, a section of undisturbed rock layers was exposed. This sequence of rock layers best illustrates the concept that (1) the living and nonliving environment both change over time (2) it is important to preserve the diversity of species and habitats (3) new inheritable characteristics can result from the recombining of genes (4) living organisms have the capacity to produce populations of unlimited size
(1) the living and nonliving environment both change over time
Which statement about the response of the body to pathogens is correct? (1) Red blood cells engulf invaders and produce antibodies that attack invaders. (2) Vaccinations may contain weakened microbes that stimulate the formation of antibodies. (3) AIDS is a bacterial disease that strengthens the immune system. (4) All allergic reactions are caused by an immune response to microorganisms.
(2) Vaccinations may contain weakened microbes that stimulate the formation of antibodies.
A DNA segment removed from neurospora (a pink mold) contained the base sequence G-T-C-C-A-T-G-C-A. A similar segment of DNA removed from neurospora that had been exposed to radiation for several hours had the base sequence G-T-C-C-A-T. This change in the base sequence is an example of (1) a deletion (3) a substitution (2) an insertion (4) a replication
(1) a deletion