Biology End Of Course Practice Test #5

Shortly after the 10th generation, there was a significant change in population between Points A and B. The most likely explanation for this change is that a fatal disease infected the rabbits. This would have caused a decrease in the population as the disease spread and affected a large number of rabbits. The other options, such as area farmers setting traps for coyotes or changes in temperature and rainfall, would not directly lead to such a drastic decline in the rabbit population.

The independent variable in Dr. Hansen's experiment is the type of cough syrup. This is because it is the variable that is being manipulated and controlled by the researcher. The other options, such as the flavor of the cough syrup, the number of people taking each cough syrup, and the number of days people take each cough syrup, are not being intentionally changed or controlled by the researcher in this experiment.

Chloroplast is the correct answer because it is a unique cellular structure found only in plant cells. It is responsible for photosynthesis, the process by which plants convert sunlight into energy. Animal cells do not have chloroplasts, so the presence of this structure distinguishes plant cells from animal cells.

The flagellated protozoan living within the intestines of a termite and helping it digest wood suggests a mutualistic relationship. Mutualism is a type of symbiotic relationship where both organisms benefit from each other. In this case, the protozoan benefits by obtaining a habitat and a source of food, while the termite benefits from the protozoan's ability to break down cellulose in wood, which it cannot digest on its own.

Lichen spores are well-suited to colonize a new volcanic island because they can survive in harsh conditions and can grow on rocks. They do not require soil to grow, making them the most likely candidate for a pioneer species on a newly formed island. Seagulls, palm trees, and insect larvae are not as well-adapted to colonize a new island without the presence of established ecosystems or suitable habitats.

Lions, cheetahs, and tigers share the most specific taxonomic level of "Family." This is because they all belong to the same family, Felidae, which is a higher taxonomic level than genus but lower than order.

If the scientist is following proper scientific procedure, she should create a new hypothesis and a new experiment to test it. This is because when the results of an experiment do not support the hypothesis, it indicates that the initial hypothesis may be incorrect. In order to further investigate and gather more accurate data, the scientist should develop a new hypothesis and design a new experiment that can provide more conclusive results. This iterative process of formulating new hypotheses and conducting experiments is essential in the scientific method to ensure accurate and reliable conclusions.

Mitosis is the process of cell division that results in the formation of two daughter cells, each with the same number of chromosomes as the parent cell. This ensures that each daughter cell receives a complete set of chromosomes, allowing for the growth, repair, and replacement of cells in multicellular organisms. Therefore, the purpose of mitosis is to produce two cells, each with one complete set of chromosomes.

The mother must be a carrier of the ALD allele because ALD is a sex-linked recessive trait. This means that the gene responsible for ALD is located on the X chromosome. Males have one X and one Y chromosome, while females have two X chromosomes. Since the father does not have ALD, he cannot be a carrier because he only has one X chromosome. The elder son also cannot be a carrier because he does not have ALD. The daughter could be a carrier, but since the younger son has ALD, it is more likely that the mother is the carrier and passed the allele onto her son.

Pistil = female part which produces the ovum
Stamen = male part which produces the sperm contained in pollen

The graph shows that both species of Paramecium exhibit a sigmoidal or S-shaped growth curve, which is characteristic of logistic growth. This type of growth occurs when a population initially grows exponentially but eventually levels off due to limited resources or other factors. In this case, P. caudatum has a higher rate of increase compared to P. bursaria, as indicated by its steeper slope on the graph. Therefore, the most accurate comparison of the two species' growth rates is that both show logistic growth, but P. caudatum has a higher rate of increase.

When red blood cells are placed in pure water, osmosis occurs. Osmosis is the movement of water molecules from an area of lower solute concentration to an area of higher solute concentration across a selectively permeable membrane. In this case, the red blood cells have a higher solute concentration (0.9% salt content) compared to the pure water. Therefore, water molecules move into the cells to equalize the solute concentration on both sides of the membrane.

In a hypotonic environment, the Paramecium faces the risk of taking in too much water, which can cause the cell to burst. To maintain homeostasis, the Paramecium expels excess water using contractile vacuoles. These vacuoles collect and pump out the excess water, preventing the cell from swelling and maintaining the balance of water inside the cell. This mechanism allows the Paramecium to survive and function properly in a hypotonic environment.

The Golgi apparatus is responsible for modifying, sorting, and packaging proteins that are synthesized in the endoplasmic reticulum. Therefore, if the chemical added by Harrison prevents movement of proteins from the endoplasmic reticulum, it would logically affect the Golgi apparatus, as proteins would not be able to reach this organelle for further processing and packaging.

During meiosis, nondisjunction can occur during Anaphase I. Anaphase I is the phase where homologous chromosomes separate and move to opposite poles of the cell. If nondisjunction occurs, it means that the chromosomes fail to separate properly, resulting in an abnormal distribution of chromosomes in the daughter cells. This can lead to genetic disorders and abnormalities in the offspring.

The criterion that is NOT necessarily true of a trait that has evolved through natural selection is that it increases individuals' life spans. While natural selection can favor traits that increase an individual's chances of survival and reproduction, it does not always result in longer life spans. Some traits that have evolved through natural selection may actually decrease life spans if they provide a reproductive advantage or other benefits that outweigh the costs of reduced longevity.

The sequence is in order from the simplest level of organization to the most complex because it starts with carbon, which is a basic element, then progresses to lipid, which is a simple organic compound, followed by mitochondrion, which is an organelle within cells, then erythrocyte, which is a type of cell, and finally muscle, which is a complex tissue made up of multiple cells.

Keisha can identify the phenotype of the cow's hair color because the question states that the dominant allele produces brown hair and the recessive allele produces white hair. Phenotype refers to the physical characteristics or traits that are expressed, in this case, the color of the cow's hair. The genotype refers to the genetic makeup of the cow, specifically the alleles it carries, which cannot be determined just by observing the cow's hair color. The genotype of the cow's parents and the phenotype of the cow's parents are not relevant to identifying the characteristic of any brown cow.

Genetic biodiversity in modern multicellular organisms is accounted for by mutations in gametes being passed on to offspring. Gametes, such as sperm and eggs, carry genetic information and any mutations that occur in these cells can be inherited by the next generation. This process of genetic variation through mutation is one of the main drivers of biodiversity, as it introduces new genetic traits and variations into populations over time.

In addition to plants, algae (protists) and some bacteria (monerans) are autotrophs (a.k.a. producers).

In a food chain, energy is transferred from one organism to another. Each organism consumes a certain amount of energy from the organism it preys upon. In this food chain, the energy is transferred from the plant to the mouse, then to the snake, then to the owl, and finally to the fungus. The energy available to the tertiary consumer, which is the owl in this case, would be the same as the energy available to the primary producer, which is 180 J.

Glycerol (C3H8O3) is a molecule composed of carbon, hydrogen, and oxygen atoms. The three identical functional groups in glycerol are hydroxyl groups (-OH). Covalent bonds hold these functional groups together within the molecule. Covalent bonds involve the sharing of electrons between atoms, allowing them to form stable molecular structures. In the case of glycerol, the covalent bonds between the carbon and oxygen atoms in the hydroxyl groups hold the functional groups together within the molecule.

In Pasteur's experiment, air could enter the flasks, but no microorganisms could enter. This is different from Spallanzani's experiment where neither air nor microorganisms could enter the flasks. By allowing air to enter the flasks, Pasteur was able to show that spontaneous generation did not occur because the broth in the flasks did not become contaminated with microorganisms from the air. This demonstrated that the presence of microorganisms was necessary for the growth of new organisms, contradicting the idea of spontaneous generation.

The cell wall of plant cells is composed of cellulose and is located outside the cell membrane. Cellulose provides rigidity and support to the cell, helping to maintain its shape. It acts as a protective barrier, preventing the cell from bursting when it absorbs water. The cell membrane, on the other hand, is a selectively permeable barrier that controls the movement of substances in and out of the cell.

When two heterozygotes for both height and flower color are crossed, the possible combinations of alleles are PPSS, PPSs, PpSS, and PpSs. Out of these combinations, only one combination (PpSs) will result in short stemmed pea plants with purple flowers. Therefore, the probability of having short stemmed pea plants with purple flowers is 1 out of 16 possible combinations, which is equivalent to 1/16.

Endocrine system produces hormones that are needed to produce gametes (ex: testosterone & estrogen).

When hydrochloric acid (HCl) is added to a solution, it dissociates into hydrogen ions (H+) and chloride ions (Cl-). Since the concentration of hydrochloric acid is increased by adding 10 mL of 5% HCl solution, the concentration of hydrogen ions (H+) will also increase. This increase in the concentration of hydrogen ions will lead to a decrease in the pH of the solution, making it more acidic. Therefore, the most likely result is that the concentration of hydrogen ions (H+) will increase.

According to cell theory, living things are composed of cells. Viruses, including feline leukemia virus, are not composed of cells. They are acellular particles that require a host cell to replicate and carry out their functions. Therefore, viruses are not considered living things based on the cell theory.

Ionic bonds are least likely to be present in organic molecules. Organic molecules are primarily composed of carbon and hydrogen atoms, which tend to form covalent bonds. Ionic bonds involve the transfer of electrons between atoms of different electronegativities, resulting in the formation of ions. Since organic molecules typically consist of nonmetallic elements, such as carbon and hydrogen, which have similar electronegativities, the formation of ionic bonds is less likely. Covalent bonds, on the other hand, involve the sharing of electrons between atoms and are more common in organic molecules.

Carbon-14, Carbon-12, and Carbon-13 are isotopes of carbon, meaning they have the same number of protons but different numbers of neutrons. The number of protons in carbon remains the same, which is 6. However, the number of neutrons differs among these isotopes. Carbon-14 has 8 neutrons, Carbon-12 has 6 neutrons, and Carbon-13 has 7 neutrons. Therefore, the correct answer is neutrons.

Cystic fibrosis is caused by a mutation in a gene that is located on an autosomal chromosome, which means it is not linked to the sex chromosomes. In autosomal recessive inheritance, both copies of the gene must have the mutation for the disease to be present. Therefore, individuals with cystic fibrosis must inherit two copies of the mutated gene, one from each parent. This mode of inheritance explains why males and females are equally affected by cystic fibrosis.

In the taiga, which is a cold and coniferous forest biome, the climax community is likely to be composed of pine trees, moose, and bears. Pine trees are well-adapted to the taiga's cold climate and acidic soil, making them dominant in the area. Moose are herbivores that feed on the pine trees and other vegetation, while bears are omnivores that feed on both plants and animals. This combination of organisms represents a typical food chain in the taiga, where the pine trees provide food and habitat for the moose, and the moose provide food for the bears.

Disruptive selection is the process of natural selection that favors the extreme phenotypes of a trait and eliminates intermediate phenotypes. This occurs when individuals with extreme variations of a trait have a higher fitness compared to individuals with intermediate variations. As a result, the population becomes divided into two distinct groups, each with their own extreme phenotype. This can lead to the formation of new species or the diversification of existing species.

Yeast respiration is a process that involves the breakdown of glucose to produce energy in the form of ATP. One of the byproducts of this process is carbon dioxide. Therefore, it is expected that a yeast culture undergoing respiration would contain carbon dioxide. Additionally, ATP is the energy currency of cells, and since yeast is actively respiring, it would require ATP for its metabolic processes. Hence, the correct answer is carbon dioxide and ATP.

The arrangement of homologous chromosomes during metaphase I varies from cell to cell. This event of meiosis is crucial for understanding Mendel's laws of segregation and independent assortment because it is during metaphase I that homologous chromosomes align randomly along the equatorial plane of the cell. This random alignment leads to the independent assortment of alleles and the segregation of different traits into different gametes, as described by Mendel's laws. Therefore, the variation in the arrangement of homologous chromosomes during metaphase I provides the mechanism for the inheritance patterns observed in Mendel's experiments.

The best explanation for the loss of hind limbs in the baleen whale is that whales with shorter hind limbs swam faster than those with longer hind limbs. This suggests that natural selection favored individuals with shorter hind limbs, as it provided them with a competitive advantage in terms of swimming speed. Over time, this trait became more prevalent in the population, leading to the reduction and eventual loss of hind limbs in baleen whales.

Nitrogenous bases combine with sugar and a phosphate group to form a nucleotide. Nucleotides are the building blocks of nucleic acids, such as DNA and RNA. They consist of a sugar molecule (in this case, deoxyribose), a phosphate group, and a nitrogenous base. The nitrogenous base is responsible for the genetic coding and determines the specific sequence of nucleotides in a DNA molecule. Different nitrogenous bases include adenine, thymine, cytosine, and guanine.

The phosphate-phosphate bond in an ATP molecule enables it to store energy for use by cells. When this bond is broken, energy is released, which can be used by cells for various metabolic processes. This bond is particularly high in energy due to the repulsion between the negatively charged phosphate groups.

The Calvin cycle and the processes in the thylakoid membrane are connected through the use of high-energy molecules. The high-energy molecules formed within the thylakoid membrane are utilized by the Calvin cycle to convert carbon dioxide into sugar molecules. This indicates that the Calvin cycle relies on the energy produced in the thylakoid membrane to carry out its function of sugar synthesis.