Biology End Of Course Practice Test #6

Mitosis is the process of cell division in which a single cell divides into two identical daughter cells. The purpose of mitosis is to produce two cells, each with 1 complete set of chromosomes. This ensures that each daughter cell receives the same genetic information as the parent cell and maintains the correct number of chromosomes. This is essential for growth, repair, and replacement of cells in multicellular organisms.

Lions, cheetahs, and tigers share the most specific taxonomic level of "Family." Taxonomic levels are hierarchical categories used to classify organisms based on their characteristics and evolutionary relationships. At the family level, organisms that share common characteristics and are closely related are grouped together. In this case, lions, cheetahs, and tigers are all part of the Felidae family, which includes all the big cats.

Shortly after the 10th generation, there was a significant decrease in the rabbit population. This sudden change is most likely caused by a fatal disease infecting the rabbits. This explanation is supported by the fact that there are no other factors mentioned in the question that could directly cause such a drastic decrease in population. The options about area farmers setting traps for coyotes, the average temperature decreasing, or the average monthly rainfall increasing do not have a direct correlation with the population change between Points A and B. Therefore, the most plausible explanation is that a fatal disease infected the rabbits.

When two heterozygotes for both height and flower color are crossed, the possible genotypes of their offspring are PPSS, PPSs, PPss, PpSS, PpSs, Ppss, ppSS, ppSs, and ppss. Out of these nine possible genotypes, only one genotype (ppss) corresponds to short stemmed pea plants with purple flowers. Therefore, the probability of having short stemmed pea plants with purple flowers is 1 out of 9, which simplifies to 1/16.

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

The independent variable in this experiment is the type of cough syrup. This is because it is the variable that is intentionally manipulated by Dr. Hansen in order to test its effectiveness. The other variables, 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 manipulated and therefore are not considered independent variables in this experiment.

When hydrochloric acid (HCl) is added to a solution, it dissociates into hydrogen ions (H+) and chloride ions (Cl-). Since the student adds hydrochloric acid, the concentration of hydrogen ions (H+) in the solution will increase. This will result in 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.

Based on the graph, Reaction I has the steepest slope at the beginning, indicating a faster initial reaction rate compared to the other reactions. This means that Reaction I is able to quickly convert reactants into products at the start of the reaction, making it the fastest in terms of initial reaction rate.

The RNA sequence GUG-GAG-AGC corresponds to the section of protein composed of Val-Glu-Ser. In RNA, the nucleotide bases are represented by the letters G, U, A, and C, which stand for guanine, uracil, adenine, and cytosine, respectively. Each three-letter sequence in the RNA represents a specific amino acid in the protein. In this case, GUG corresponds to the amino acid valine (Val), GAG corresponds to glutamic acid (Glu), and AGC corresponds to serine (Ser). Therefore, the given RNA sequence matches the sequence of Val-Glu-Ser.

In the taiga, which is a cold and coniferous forest biome, the climax community is typically dominated by pine trees. Moose and bears are also commonly found in this biome. The pine trees provide habitat and food for the moose, while the bears feed on both the moose and the pine nuts. This group of organisms forms a balanced and stable ecosystem in the taiga, making them the most likely to be part of the resulting climax community in an abandoned football field in the taiga.

In a hypotonic environment, the concentration of solutes outside the Paramecium is lower than inside its cytoplasm. This causes water to move into the Paramecium through osmosis, potentially leading to the cell bursting. 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 and solutes inside the cell.

In a food chain, energy is transferred from one organism to another. The energy transfer is not 100% efficient, and only a portion of the energy is passed on to the next trophic level. In this case, the energy is being transferred from the producer (plant) to the tertiary consumer (fungus) through multiple trophic levels (mouse, snake, owl). Each trophic level only receives a fraction of the energy from the previous level. Therefore, the amount of energy that would be able to be transferred to the tertiary consumer (fungus) would be the same as the initial amount of energy from the producer, which is 180 J.

The Calvin cycle and the processes occurring within the thylakoid membrane are connected through the use of high-energy molecules. The high-energy molecules formed within the thylakoid membrane during the light-dependent reactions of photosynthesis are used by the Calvin cycle to convert carbon dioxide into sugar molecules. This connection allows for the transfer of energy and the production of glucose, which is essential for the overall process of photosynthesis.

Glycerol (C3H8O3) contains three identical functional groups, which are held together by covalent bonds. Covalent bonds involve the sharing of electrons between atoms, allowing the atoms to form stable molecules. In the case of glycerol, the three functional groups are attached to the carbon atoms through covalent bonds, ensuring the stability and integrity of the molecule.

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

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 for various cellular processes. This bond is high in energy due to the negative charges on the phosphate groups and the repulsion between them. The release of this energy allows ATP to provide the necessary energy for cellular activities such as muscle contraction, active transport, and synthesis of macromolecules.

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 they had a selective advantage in terms of speed and maneuverability in the water. Over time, this led to the reduction and eventual loss of hind limbs in the baleen whale population.

Scientists concluded that in all organisms, the percentages of A and T are equal, and the percentages of G and C are also equal.

The Golgi apparatus is responsible for modifying, sorting, and packaging proteins that are synthesized in the endoplasmic reticulum. In this scenario, the chemical added by Harrison prevents the movement of proteins from the endoplasmic reticulum to the Golgi apparatus. This explains why the proteins accumulate in the endoplasmic reticula of the cells.

If the scientist's results do not support her hypothesis, it means that her initial assumption was incorrect. In order to continue following proper scientific procedure, she should reject the hypothesis and assume it is incorrect. To further investigate the phenomenon, she should create a new hypothesis based on the new information gathered from the experiment and design a new experiment to test it. This allows the scientist to continue the scientific process by formulating new ideas and conducting further experiments to gain a better understanding of the phenomenon in question.

A trait that has evolved through natural selection does not necessarily increase individuals' life spans. Natural selection favors traits that enhance an individual's reproductive success, not necessarily their longevity. While some traits may indirectly contribute to longer life spans, such as traits that improve resistance to diseases or increase overall fitness, the primary focus of natural selection is on traits that increase an individual's chances of successfully reproducing and passing on their genes to the next generation.

During Anaphase I of meiosis, the homologous chromosomes separate and move to opposite poles of the cell. Nondisjunction occurs when these chromosomes fail to separate properly, leading to an abnormal distribution of chromosomes in the resulting cells. This can result in aneuploidy, where the cells have an abnormal number of chromosomes. Therefore, Anaphase I is the phase of meiosis where nondisjunction is most likely to occur.

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. Chloroplasts contain chlorophyll, a green pigment that gives plants their color and allows them to absorb sunlight. Animal cells do not have chloroplasts, which is why they are unable to carry out photosynthesis. Therefore, the presence of chloroplasts distinguishes plant cells from animal cells.

Both species of Paramecium show logistic growth, which is evident from the S-shaped curve in the graph. Logistic growth occurs when a population initially grows exponentially but then levels off as it reaches the carrying capacity of its environment. In this case, both species show a similar pattern of growth, but P. caudatum has a higher rate of increase, as indicated by its steeper slope on the graph. This means that P. caudatum is able to reproduce and increase its population size at a faster rate compared to P. bursaria.

Lichen spores deposited on rocks by the wind are the most likely candidate for a pioneer species because lichens are known to be one of the first organisms to colonize barren or newly formed land. Lichens are a symbiotic combination of fungi and algae, and they can survive in harsh conditions with minimal nutrients. Their ability to grow on rocks and obtain nutrients from the air makes them well-suited for colonizing volcanic islands where the soil is initially lacking in nutrients. Therefore, lichen spores carried by the wind and deposited on rocks would be able to establish themselves and begin the process of primary succession on the island.

The relationship between the flagellated protozoan and the termite is most likely mutualistic. This is because the protozoan helps the termite digest wood, which is a benefit for the termite. In return, the protozoan gets a stable environment and a source of food. Both organisms benefit from this interaction, indicating a mutualistic relationship.

In this instance of osmosis, the red blood cells are placed in pure water, which means that the concentration of solutes outside the cells is lower than inside the cells. As a result, water molecules move from an area of higher concentration (outside the cells) to an area of lower concentration (inside the cells) in order to equalize the concentration on both sides of the cell membrane. Therefore, water molecules move into the cells.

The number of neutrons varies among carbon isotopes. Carbon-14 has 8 neutrons, carbon-12 has 6 neutrons, and carbon-13 has 7 neutrons. Electrons, photons, and protons are not the subatomic particles that vary in number among carbon isotopes.

During yeast respiration, glucose is broken down into carbon dioxide and ethanol. This process, known as fermentation, occurs in the absence of oxygen. Therefore, the yeast culture would contain carbon dioxide, which is a byproduct of fermentation. Additionally, ATP is produced during cellular respiration as a form of energy currency. Therefore, the yeast culture would also contain ATP.

Mutations in gametes are passed to offspring. This is because gametes, such as eggs and sperm, contain the genetic material that is passed on to the next generation. Mutations, which are changes in the DNA sequence, can occur in gametes and be inherited by offspring. These mutations can lead to genetic diversity in modern multicellular organisms as each individual may have different variations in their genetic makeup. This genetic diversity is important for the survival and adaptation of species in changing environments.

Plant cells have a cell wall composed of cellulose, which is located outside the cell membrane. The cell wall provides structural support and protection to the cell, preventing it from bursting or collapsing under pressure. The cell membrane, on the other hand, is a selectively permeable barrier that controls the movement of substances in and out of the cell. The cellulose cell wall acts as an additional layer of protection and support, surrounding the cell membrane.

Since ALD is a sex-linked recessive trait, it is carried on the X chromosome. The father can only pass on a Y chromosome to his sons, so he cannot be a carrier. The elder son does not have ALD, so he cannot be a carrier. The daughter does not have ALD, so she cannot be a carrier. Therefore, the only possibility is that the mother is a carrier and passed on the ALD allele to her younger son.

This molecule is an example of an amino acid. Amino acids are the building blocks of proteins and contain an amino group (-NH2) and a carboxyl group (-COOH) attached to a central carbon atom. They also have a variable side chain (R-group) that differentiates one amino acid from another.

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. The phenotype refers to the observable characteristics of an organism, in this case, the hair color. Therefore, by observing the cow's hair color, Keisha can determine whether it has brown or white hair and thus identify the phenotype of the cow's hair color.

Viruses are not considered living things according to cell theory because they are not composed of cells. Viruses are acellular entities that are made up of genetic material (DNA or RNA) enclosed in a protein coat. They cannot carry out essential life processes on their own and require a host cell to reproduce. While they can replicate and evolve, they do not possess the cellular structure and organization that is characteristic of living organisms. Therefore, the correct answer is "No, because they are not composed of cells."

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. The presence of air in Pasteur's experiment allowed for the possibility of spontaneous generation, as some believed that air was necessary for the creation of life. However, by using a curved-neck flask that prevented microorganisms from entering, Pasteur was able to show that spontaneous generation did not occur.

Disruptive selection is the process of natural selection that favors extreme phenotypes of a trait and eliminates intermediate phenotypes. This occurs when individuals with extreme traits have a higher fitness compared to individuals with intermediate traits. Over time, this leads to the divergence of the population into two distinct phenotypic groups.

The correct answer is carbon, lipid, mitochondrion, erythrocyte, muscle. This sequence is in order from the simplest level of organization to the most complex. Carbon is a single element, lipid is a type of molecule, mitochondrion is an organelle, erythrocyte is a cell, and muscle is a tissue made up of cells.

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

Cystic fibrosis is inherited in an autosomal recessive manner. This means that both copies of the gene responsible for the disease, known as CFTR, must have the mutation in order for an individual to have cystic fibrosis. Since males and females must inherit two alleles with this mutation to have the disease, it confirms that the mode of inheritance is autosomal recessive.

Ionic bonds are least likely to be present in organic molecules. Organic molecules primarily consist of carbon and hydrogen atoms, which typically form covalent bonds. Ionic bonds involve the transfer of electrons between atoms of opposite charges, whereas covalent bonds involve the sharing of electrons. Since organic molecules are based on covalent bonding, it is unlikely for them to have ionic bonds.

Nitrogenous bases combine with sugar and a phosphate group to form a nucleotide. A nucleotide is the basic building block of nucleic acids, such as DNA and RNA. Nitrogenous bases are organic molecules that contain nitrogen and are classified into two types: purines (adenine and guanine) and pyrimidines (cytosine, thymine, and uracil). These bases bond with a sugar molecule (in DNA, it is deoxyribose) and a phosphate group to create a nucleotide.

During metaphase I of meiosis, homologous chromosomes line up in pairs along the equator of the cell. This arrangement is known as independent assortment. It is the random alignment of chromosomes that allows for different combinations of alleles to be passed on to the gametes, leading to genetic variation. This mechanism is crucial for understanding Mendel's laws of segregation and independent assortment, as it explains how different traits are inherited independently from each other.