Biology I Final Exam (Practice)

Mimicry is not considered a characteristic of life because it is a behavior or adaptation that some organisms use to imitate or resemble other organisms or objects in their environment. While mimicry can be a survival strategy, it is not an inherent characteristic of living organisms. The other options, growth and development, reproduction, and energy use, are all fundamental characteristics of life that are necessary for the survival and continuation of living organisms.

Mitochondria are responsible for the production of energy for our cells. They are often referred to as the "powerhouses" of the cell because they generate adenosine triphosphate (ATP), which is the main source of energy for cellular processes. Mitochondria have their own DNA and are able to produce their own proteins, allowing them to carry out the process of cellular respiration and produce ATP through oxidative phosphorylation. This energy production is essential for the functioning of our cells and overall organism.

Charles Darwin proposed the theory of evolution by the mechanism of natural selection. This theory states that individuals with favorable traits are more likely to survive and reproduce, passing on those traits to future generations. Over time, this process leads to the gradual change and adaptation of species to their environment. Natural selection is a key mechanism in Darwin's theory of evolution and is supported by extensive evidence from various fields of study.

A nucleotide is a building block of nucleic acids, such as DNA and RNA. It consists of three main components: a sugar molecule (either deoxyribose or ribose), a nitrogenous base (adenine, thymine, cytosine, guanine, or uracil), and a phosphate group. These components are joined together to form a nucleotide, which then combine with other nucleotides to form the DNA or RNA molecule. Therefore, option B is the correct answer as it accurately describes the composition of a nucleotide.

Proteins play a crucial role in various processes in or on the plasma membrane. They can act as enzymes, catalyzing biochemical reactions and facilitating metabolic processes (A. enzymatic activity). Proteins also contribute to cell-cell recognition, allowing cells to identify and interact with each other (B. cell-cell recognition). Additionally, proteins are involved in active transport, which is the movement of molecules across the membrane against their concentration gradient (C. active transport). Lastly, proteins are essential for cell-cell communication, enabling cells to send and receive signals (D. cell-cell communication). Therefore, all of the mentioned processes result from the presence of proteins in or on the plasma membrane (E. all of the above).

Covalent bonding is a type of chemical bonding where atoms share electrons. This sharing of electrons allows both atoms to achieve a stable electron configuration, resulting in a more stable molecule. In covalent bonding, neither atom completely loses or gains electrons, but rather they share them in order to fill their outermost electron shells. This type of bonding is typically found between nonmetal atoms.

The answer is C. eight. This is because elements strive to have a full outer electron shell, which typically consists of eight electrons. When an element has a full outer shell, it is stable and less likely to react with other elements. This is known as the octet rule. Therefore, eight electrons are required for an element to be stable and non-reactive.

Organic compounds are compounds that contain carbon atoms bonded to hydrogen atoms. They are classified into four main classes: lipids, proteins, nucleic acids, and carbohydrates. Water, however, is not considered an organic compound because it does not contain carbon atoms bonded to hydrogen atoms. Therefore, the correct answer is A. water.

In an enzymatic reaction, the reactants are referred to as substrates because they are the molecules that the enzyme acts upon. Enzymes are proteins that catalyze chemical reactions by binding to specific substrates and facilitating their conversion into products. The substrates bind to the active site of the enzyme, where the reaction takes place. Therefore, it is correct to say that the reactants in an enzymatic reaction are called the substrates for that enzyme.

The correct answer is D. all of the above. Enzymatic reactions are affected by temperature and pH because enzymes have an optimal temperature and pH range at which they function most efficiently. Inhibitors can also affect enzymatic reactions by binding to the enzyme and preventing it from carrying out its normal function. The amounts of substrate and enzyme also play a role in the speed of enzymatic reactions. If there is an excess of substrate or enzyme, the reaction may proceed faster, while a limited amount of either can slow down the reaction. Therefore, all of these factors can affect enzymatic reactions and their speed.

ATP (adenosine triphosphate) is considered the energy currency of cells because it is the molecule that carries and provides energy for cellular processes. When ATP is hydrolyzed, it releases energy that can be used by cells to perform various functions such as muscle contraction, active transport, and synthesis of macromolecules. Glucose is a source of energy, but it needs to be broken down into ATP before it can be used. Oxygen is involved in cellular respiration but is not the actual energy currency. Proteins are essential for various cellular functions but do not directly serve as the energy currency.

The types of RNA mentioned in the options are messenger RNA (mRNA), transfer RNA (tRNA), and ribosomal RNA (rRNA). These three types of RNA are involved in different stages of protein synthesis. Messenger RNA carries the genetic information from DNA to the ribosomes, transfer RNA brings amino acids to the ribosomes during translation, and ribosomal RNA forms the structural and catalytic components of ribosomes. Therefore, the correct answer is B. nuclear, as there is no specific type of RNA called "nuclear RNA" mentioned in the options.

The correct answer is D. a six carbon glucose sugar. This is because a nucleotide of DNA consists of a five carbon deoxyribose sugar, a nitrogenous base, and a phosphate group. Glucose is a different type of sugar and is not found in DNA nucleotides.

The correct answer is E. This sequence correctly lists the different levels of biological organization, starting from the smallest unit (cells) and progressing to larger structures (tissues, organs, organ systems, and finally the whole organism). This sequence follows the hierarchical organization of living organisms, where cells combine to form tissues, tissues combine to form organs, organs work together to form organ systems, and all of these components come together to form a complete organism.

As air temperature warms during the day from 50 to 70 degrees, water in the same area will warm more slowly. This is because water has a higher specific heat capacity compared to air. Specific heat capacity is the amount of heat energy required to raise the temperature of a substance by a certain amount. Since water has a higher specific heat capacity, it requires more heat energy to raise its temperature compared to air. Therefore, the water will warm at a slower rate than the air.

Carbohydrates are not directly associated with enzymes. Carbohydrates are a type of macromolecule that serve as a source of energy and provide structural support, while enzymes are proteins that act as catalysts in biochemical reactions. Although enzymes can interact with carbohydrates in certain reactions, the association between carbohydrates and enzymes is not a direct one.

Metabolism refers to the sum of all chemical reactions that take place within a living cell. These reactions include both catabolic reactions, which break down molecules to release energy, and anabolic reactions, which build up molecules using energy. Therefore, metabolism encompasses all the processes involved in converting food into energy, synthesizing new molecules, and maintaining the overall functioning of the cell.

Different alleles in a given pair are described as heterozygous. Heterozygous refers to having two different alleles for a particular trait. In this case, the individual has two different versions of the gene in the pair, one from each parent. This is in contrast to homozygous, where the individual has two identical alleles for the trait. Genotype refers to the genetic makeup of an individual, while phenotype refers to the physical expression of the genotype.

When a disease is said to have a multifactorial basis, it means that both genetic and environmental factors contribute to the disease. This suggests that the disease is not solely caused by genetic factors or environmental factors alone, but rather a combination of both. This understanding is important in determining the risk factors, prevention strategies, and treatment options for the disease.

Natural selection is the only evolutionary mechanism that consistently leads to adaptive evolution. This process involves the differential survival and reproduction of individuals with favorable traits, leading to the accumulation of advantageous genetic variations in a population over time. Through natural selection, individuals with traits that enhance their ability to survive and reproduce in a given environment are more likely to pass on their genes to the next generation. This results in the gradual adaptation of a population to its environment, as individuals with beneficial traits become more prevalent.

The atomic weight of an element is calculated by adding the number of protons and neutrons in the nucleus of an atom. Protons have a positive charge and neutrons have no charge, therefore their combined number represents the mass of the atom. Electrons, on the other hand, have a negligible mass compared to protons and neutrons, so they are not included in the calculation of atomic weight. Therefore, the correct answer is C. number of protons + neutrons.

Phagocytosis is the process by which white blood cells engulf and ingest bacteria. This process involves the formation of pseudopodia, which surround and engulf the bacteria, forming a phagosome. The phagosome then fuses with lysosomes, forming a phagolysosome, where the bacteria are broken down and destroyed. This is an important mechanism of the immune system to eliminate harmful bacteria and other pathogens from the body.

Anaphase is the correct answer because it is the phase of mitosis where the sister chromatids separate and move to opposite poles of the cell. During anaphase, the centromeres uncouple and the two new chromosomes are pulled apart by the spindle fibers towards the opposite ends of the cell. This is a crucial step in cell division as it ensures that each daughter cell receives a complete set of chromosomes.

Vertical lines in a pedigree chart represent offspring. This is because the vertical lines connect the parents to their children, showing the lineage and the generations in the family tree. The offspring are the direct descendants of the parents, and the vertical lines indicate the continuation of the family line through the generations.

The suffix "ose" is commonly found in the names of sugars. This suffix is used to indicate that a compound is a sugar, such as glucose, fructose, and sucrose. Therefore, option A is the correct answer.

Facilitated diffusion is a passive transport process that allows the movement of specific molecules across a cell membrane with the help of transport proteins. The given answer, "E. all of the above," is correct because facilitated diffusion requires a concentration gradient, a membrane through which the molecules can pass, involves proteins (specifically transport proteins), and does not require an outside energy source. Therefore, all of the statements mentioned in options A, B, C, and D are true about facilitated diffusion.

An isotonic solution refers to a solution where the solute concentration is the same inside and outside the cell. In this scenario, there is no net movement of water across the cell membrane, as the concentration of solutes is balanced on both sides. This allows the cell to maintain its shape and normal functions without any water loss or gain.

This answer is correct because the statement describes a situation where the offspring of homozygous purple-flowered and homozygous white-flowered pea plants have purple flowers. This indicates that the purple flower trait is dominant over the white flower trait, supporting the concept of dominance in genetics.

Carbohydrates are organic compounds composed of carbon, hydrogen, and oxygen atoms. They can be classified into three main types: monosaccharides, disaccharides, and polysaccharides. Complex carbohydrates include starches and glycogen. However, the concept of saturation or unsaturation is not applicable to carbohydrates. This property is typically associated with fats and oils, which are composed of different types of fatty acids. Therefore, option C does not apply to carbohydrates.

The plasma membrane is a flexible and dynamic structure that surrounds the cell. It is composed of a phospholipid bilayer that allows for fluid movement of molecules. The term "mosaic" refers to the presence of various proteins and lipids embedded in the membrane, giving it a mosaic-like appearance. Lastly, the plasma membrane is selectively permeable, meaning it regulates the passage of substances in and out of the cell. However, it is not rigid, as it needs to be flexible to accommodate cellular processes such as endocytosis and cell movement.

Passive transport is a process in which substances move across a cell membrane without the use of energy. Diffusion, facilitated diffusion, and osmosis are all examples of passive transport. Diffusion is the movement of molecules from an area of high concentration to an area of low concentration. Facilitated diffusion is the movement of molecules across the membrane with the help of transport proteins. Osmosis is the movement of water molecules across a selectively permeable membrane. Receptor-mediated transport, on the other hand, involves the binding of a substance to a specific receptor on the cell membrane, which then triggers the transport of the substance into the cell. Therefore, receptor-mediated transport is not a type of passive transport.

In a nucleosome, the DNA is wrapped around histones. Histones are proteins that help in organizing and compacting the DNA molecule. They act as spools around which the DNA is wound, forming a structure called chromatin. This packaging of DNA with histones allows for efficient storage and regulation of genetic information.

The question is asking which option is NOT included in the domains or "superkingdoms." The domains include Bacteria, Archaea, and Eukarya. Animalia, which refers to the kingdom of animals, is not a domain or "superkingdom" and is therefore not included.

The shape of a protein is a critical characteristic that determines its function. Proteins are made up of long chains of amino acids that fold into specific three-dimensional shapes. This shape is essential for the protein to interact with other molecules and perform its specific function. Different shapes allow proteins to bind to specific targets, catalyze chemical reactions, transport molecules, or provide structural support. Therefore, the shape of a protein directly influences its ability to carry out its intended function.

DNA is replicated during the S phase of the cell cycle. This is the phase where DNA synthesis occurs, and the cell prepares to divide by replicating its genetic material. The S phase is followed by the G2 phase, where the cell continues to grow and prepare for cell division. Therefore, the correct answer is C. S.

The correct answer is B. A+G=C+T. This answer is consistent with the base-pairing rules because it states that the amount of adenine (A) plus the amount of guanine (G) is equal to the amount of cytosine (C) plus the amount of thymine (T). This is in accordance with Chargaff's rules, which state that in DNA, the amount of adenine is equal to the amount of thymine, and the amount of guanine is equal to the amount of cytosine.

The founder effect occurs when a small group of individuals becomes isolated from a larger population and establishes a new population. This small group carries only a fraction of the genetic diversity of the original population, resulting in a limited gene pool. Over time, this can lead to the accumulation of unique genetic traits in the new population, as well as an increased likelihood of genetic disorders. Therefore, the founder effect is the most appropriate explanation for the given scenario.

Lipids are a diverse group of molecules that include phospholipids, waxes, and steroids. Phospholipids are a major component of cell membranes, waxes are found in the protective coatings of plants and animals, and steroids are important for various physiological functions. However, albumin is a protein and not a lipid. It is a soluble protein found in blood plasma and plays a role in maintaining osmotic pressure and transporting molecules.

During prophase, the chromosomes condense and become visible under a microscope. This is the first stage of mitosis, where the nuclear envelope starts to break down and the spindle fibers begin to form. In prometaphase, the nuclear envelope fully disintegrates and the spindle fibers attach to the chromosomes. In metaphase, the chromosomes align at the center of the cell. In anaphase, the sister chromatids separate and move towards opposite poles of the cell. In telophase, the chromosomes reach the poles and the nuclear envelope reforms.

A codon consists of three bases and specifies which amino acid will be inserted into the polypeptide chain. Each codon is a sequence of three nucleotides that corresponds to a specific amino acid. Therefore, the correct answer is E. 3; amino acid.

tRNA, or transfer RNA, is the type of RNA that carries amino acids within the cytoplasm. This molecule plays a crucial role in protein synthesis by transferring the correct amino acids to the ribosomes, where they are assembled into a polypeptide chain according to the instructions carried by mRNA. tRNA has a specific structure that allows it to recognize and bind to both the mRNA codon and the corresponding amino acid, ensuring that the correct amino acid is added to the growing protein chain.

Carbon is known for its ability to form covalent bonds, meaning it shares electrons with other atoms. It has 4 electrons in its outer shell, making it versatile for bonding. Additionally, carbon is a key component of organic compounds, along with hydrogen. However, carbon does not typically form ionic bonds, where electrons are transferred between atoms. This is because carbon's electronegativity is not high enough to attract electrons strongly enough for ionic bonding.

A hypertonic solution has a higher concentration of solute and a lower concentration of water compared to inside the cell. When a cell is placed in a hypertonic solution, water will flow out of the cell to try to equalize the concentration of solute on both sides of the cell membrane. This causes the cell to shrink or shrivel up.

The given question asks for the mode of selection that is not included in the options provided. The options include disruptive, directional, and stabilizing. These are all modes of selection that can occur in evolutionary processes. However, connecting is not a recognized mode of selection in evolutionary biology. Therefore, option A is the correct answer.

Enzymes are biological catalysts that speed up chemical reactions in cells. They do this by lowering the energy of activation required for the reactions to occur. By decreasing the energy of activation, enzymes make it easier for the reactants to reach the transition state and proceed with the reaction. This allows reactions to happen more quickly and efficiently. Therefore, the correct answer is B. decrease.

The given descriptions of reactions that involve the breakdown of ATP and result in products with less energy than the reactants align with the characteristics of exergonic reactions. In exergonic reactions, energy is released, and the products have lower energy than the reactants. This energy release is often used to drive cellular processes. Therefore, option D, exergonic reactions, is the correct answer.

Lactic acid fermentation is the correct answer because it is the type of respiration that occurs within animal muscle cells to quickly gain energy. During intense exercise, when oxygen supply is limited, muscle cells switch to lactic acid fermentation to produce ATP. This process breaks down glucose into lactic acid, releasing energy in the process. This allows the muscles to continue contracting even without sufficient oxygen supply.

The correct answer is C because it represents the overall reaction of aerobic cellular respiration. In this reaction, glucose (C6H12O6) is combined with oxygen (O2) to produce carbon dioxide (CO2) and water (H2O), while also generating ATP. This equation accurately reflects the process of aerobic cellular respiration, where glucose is broken down in the presence of oxygen to release energy in the form of ATP, along with the production of carbon dioxide and water as waste products.

The process of transcription involves the synthesis of mRNA from a DNA template. During transcription, DNA unzips and the RNA polymerase enzyme adds complementary RNA nucleotides to the exposed DNA strand. This results in the formation of an mRNA molecule. Option D is incorrect because it states that free nucleotides join the DNA molecule, which is not a part of the transcription process. Instead, it is during DNA replication that free nucleotides join the DNA molecule to create a new DNA strand.

Gene flow refers to the transfer of genetic material from one population to another. It occurs when individuals from different populations mate and produce offspring, resulting in the exchange of genes between the populations. This process helps to maintain genetic diversity within populations and can prevent the accumulation of genetic differences that could lead to speciation. Therefore, gene flow is best used to describe an exchange between populations rather than species, males and females, individuals, or chromosomes.