Final Biology Exam *

The major biological macromolecules, such as proteins, nucleic acids, carbohydrates, and lipids, are all composed of monomer subunits. These monomers are joined together through chemical reactions, such as dehydration synthesis, to form larger macromolecules. Each macromolecule has its own specific set of monomers that make up its structure and function. This characteristic of consisting of monomer subunits is a fundamental property of biological macromolecules across different organisms.

ATP (Adenosine Triphosphate) is the correct answer because it is the main energy currency in cells. During the light-dependent phases of photosynthesis, light energy is converted into chemical energy in the form of ATP. This energy is then used in the light-independent phase (Calvin cycle) to convert CO2 into glucose, the main product of photosynthesis. Therefore, while glucose is also a product of photosynthesis, it is not stored at the end of the light-dependent phases, but rather ATP is stored as the immediate energy source for cellular processes.

The inclusion of 3 nitrogenous bases in a codon is necessary for coding for 20 different amino acids. A codon is a sequence of three nucleotides in mRNA that corresponds to a specific amino acid. There are 4 different nitrogenous bases in DNA (adenine, cytosine, guanine, and thymine), and by combining them in different sequences of three, it is possible to create 64 different codons. Since there are only 20 different amino acids, some amino acids are coded by multiple codons, allowing for redundancy in the genetic code. Therefore, the inclusion of 3 nitrogenous bases in a codon is necessary for coding for all 20 different amino acids.

The polarity of individual water molecules contributes to the solvent properties of water. Water is a polar molecule, meaning it has a slight positive charge on one end and a slight negative charge on the other. This polarity allows water molecules to attract and surround other polar molecules, such as salts or sugars, and dissolve them. This property of water as a solvent is essential for many biological processes, as it allows for the transport of nutrients and waste products within cells and throughout organisms.

When a single-celled freshwater organism is placed in a container of saltwater, it would face the problem of shrinking. This is because the saltwater has a higher concentration of salts compared to the organism's internal environment. As a result, water from the organism's cells would move outwards, following the principle of osmosis, to balance the concentration of salts. This loss of water causes the organism to shrink in size.

During meiosis, the process of cell division that produces gametes, the X and Y chromosomes segregate. This means that half of the male gametes will carry an X chromosome and the other half will carry a Y chromosome. When fertilization occurs, if a sperm carrying an X chromosome fertilizes the egg, the resulting offspring will be female. If a sperm carrying a Y chromosome fertilizes the egg, the resulting offspring will be male. Therefore, due to the segregation of the X and Y chromosomes during meiosis, it is predicted that half of the human babies born will be males and half will be females.

Cystic Fibrosis is a genetic disorder that is caused by a mutation affecting the amino acid Phe508 and chromosomes #7. This mutation leads to the inability to synthesize a protein that transports Cl- across the cell membrane. As a result, individuals with cystic fibrosis experience a build-up of mucus in the lungs, which can lead to respiratory problems. This explanation fits with the given symptoms and genetic information provided.

The correct answer is CcDd x CcDd. This is because the child has straight, light colored hair, which indicates that they have a genotype of ccdd. In order for the child to have this genotype, both parents must have at least one copy of the recessive alleles for both traits. The CcDd genotype allows for the possibility of passing on both recessive alleles to the child, resulting in their phenotype.

During the Krebs Cycle, also known as the citric acid cycle, two molecules of ATP are formed. This cycle is an important part of cellular respiration, where glucose is broken down to produce energy in the form of ATP. In each turn of the cycle, one molecule of ATP is produced through substrate-level phosphorylation, resulting in a total of two ATP molecules at the end of the cycle.

During photosynthesis, plants use carbon dioxide (CO2) as the source of carbon to synthesize carbohydrates. Carbon dioxide enters the plant through small openings called stomata on the leaves. Inside the leaf, it is converted into glucose through a series of chemical reactions known as the Calvin cycle. Glucose is a type of carbohydrate that plants use as a source of energy and for building other complex molecules like cellulose and starch. Therefore, CO2 is the correct answer as it provides the necessary carbon atoms for the synthesis of carbohydrates during photosynthesis.

The electron transport system is the metabolic pathway that produces the greatest number of ATP. During this process, electrons from NADH and FADH2 are transported through a series of protein complexes in the inner membrane of the mitochondria. As the electrons move through these complexes, energy is released and used to pump protons across the membrane, creating an electrochemical gradient. This gradient is then used by ATP synthase to produce ATP. Overall, the electron transport system is highly efficient and can generate a large amount of ATP compared to other metabolic pathways such as glycolysis, the Krebs cycle, and the Calvin cycle.

The correct answer is "A section of DNA that is used to synthesize a particular protein." This is because a gene is a specific sequence of DNA that contains the instructions for making a particular protein. Genes are responsible for determining the traits and characteristics of an organism.

In this species, the cells of the giant tetradon spider contain 34 homologous chromosome pairs. Since each chromosome pair consists of two chromosomes, the total number of chromosomes in these cells is 34 x 2 = 68. Therefore, the correct answer is 68.

Lipids do not dissolve easily in water because they are nonpolar. Water is a polar molecule, meaning it has a slight positive charge on one end and a slight negative charge on the other. Nonpolar molecules, like lipids, do not have a charge and are therefore not attracted to water molecules. This lack of attraction makes it difficult for lipids to dissolve in water, resulting in the separation of the two substances.

The rough and smooth endoplasmic reticulum differ by the presence of ribosomes. The rough endoplasmic reticulum has ribosomes attached to its surface, while the smooth endoplasmic reticulum lacks ribosomes. This difference in ribosome presence affects the functions of the two types of endoplasmic reticulum. The rough endoplasmic reticulum is involved in protein synthesis and processing, while the smooth endoplasmic reticulum is involved in lipid metabolism, detoxification, and calcium storage. Therefore, the presence or absence of ribosomes is a key distinguishing factor between the rough and smooth endoplasmic reticulum.

The electron transport system is responsible for generating energy in the form of ATP. NADH and FADH2 are electron carriers that are produced during the breakdown of glucose in cellular respiration. These molecules carry high-energy electrons to the electron transport system, where they are used to create a proton gradient. This gradient is then used to power the production of ATP. Therefore, NADH and FADH2 are the correct answers as they enter the electron transport system with stored energy.

Carbohydrates are the most abundant organic molecules found on Earth. They are essential for energy storage and provide structural support in living organisms. Carbohydrates are found in various forms such as sugars, starches, and cellulose. They are widely distributed in plants and form a major component of plant cell walls. Additionally, carbohydrates are also present in animal tissues and are a primary source of energy for both plants and animals. Due to their widespread presence and importance in biological systems, carbohydrates are the most abundant organic molecules on Earth.

Phagocytosis is the process in which a cell engulfs large particles or molecules by forming extensions of its plasma membrane. This process is specifically designed to take in large molecules or particles that cannot enter the cell through simple diffusion or osmosis. Therefore, the correct answer is phagocytosis.

Transcription is the process of synthesizing RNA based on information in DNA. This process occurs in the nucleus of a cell and involves the enzyme RNA polymerase. During transcription, the DNA molecule is unwound and one strand serves as a template for the synthesis of a complementary RNA molecule. This RNA molecule, known as messenger RNA (mRNA), carries the genetic information from the DNA to the ribosomes in the cytoplasm, where it is used as a template for protein synthesis. Therefore, the correct answer is synthesizing RNA based on information in DNA.

The correct answer is two cells that are exactly identical in every way. During mitosis, a single cell divides into two daughter cells, each containing the same genetic material as the parent cell. This process ensures that the genetic information is accurately replicated and distributed equally between the two cells. As a result, the two daughter cells produced through mitosis are identical to each other and to the original parent cell.

Enzymes play a crucial role in cellular metabolism by facilitating various biochemical reactions. They act as catalysts, speeding up the rate of these reactions. In the context of the question, enzymes prevent the breakdown of cell parts containing energy by regulating the metabolic processes. This ensures that energy is utilized efficiently and only when needed. Therefore, enzymes are involved in maintaining the integrity of cell parts and preventing their unnecessary degradation.

Translation specifically refers to the process of assembling amino acids according to an RNA template. During translation, the mRNA molecule carries the genetic information from the DNA molecule to the ribosomes, where it is used as a template to synthesize a specific sequence of amino acids. This process occurs in the cytoplasm of cells, not within the nucleus. Therefore, the correct answer is the assembly of amino acids according to an RNA template.

Chlorophyll molecules are responsible for producing oxygen during photosynthesis. Photosynthesis is the process by which plants convert sunlight, carbon dioxide, and water into glucose (energy) and oxygen. Chlorophyll, a pigment found in plant cells, absorbs the sunlight and uses its energy to convert water molecules into oxygen and hydrogen ions. The oxygen is then released into the atmosphere as a byproduct. Therefore, chlorophyll molecules play a crucial role in the production of oxygen during photosynthesis.

Catabolism is the correct answer because it refers to the breakdown of molecules and the release of energy in metabolic reactions. This process involves the breaking down of complex molecules into simpler ones, which releases energy that can be used by the cell for various functions. Anabolism, on the other hand, refers to the synthesis of complex molecules from simpler ones, and ATP using is not a recognized term in the context of metabolic pathways. Therefore, the correct answer is catabolism.

In the process of glycolysis, energy is obtained from the breakdown of glucose molecules. Glucose is a carbohydrate that serves as the primary source of energy for cellular respiration. During glycolysis, glucose is converted into pyruvate, releasing energy in the form of ATP (adenosine triphosphate) and NADH (nicotinamide adenine dinucleotide). Therefore, glucose is the correct answer as it is the initial molecule that provides the stored energy for glycolysis to occur.

The Krebs Cycle, also known as the citric acid cycle, is a metabolic pathway that occurs in the mitochondria of cells. During this cycle, acetyl-CoA is oxidized, producing carbon dioxide (CO2) as a byproduct. This CO2 is then released into the bloodstream and eventually exhaled from the body. Therefore, the majority of CO2 is produced in the Krebs Cycle. Glycolysis, on the other hand, primarily produces ATP and pyruvate, while the electron transport system generates ATP and water. The Calvin Cycle, found in plants, is responsible for carbon fixation and the production of glucose.

The answer suggests that not all genes in your DNA are expressed at the same frequency. Some genes are expressed constantly, meaning they are active and producing proteins throughout various life stages. On the other hand, other genes are expressed infrequently, indicating that they are only active and producing proteins under specific circumstances or conditions. This highlights the dynamic nature of gene expression and the complex regulation of gene activity in the human body.

The given question asks for the cause of about 85% of human cancers. The correct answer is "Genetic Disorder." This means that the majority of human cancers are caused by abnormalities or mutations in genes that control cell growth and division. These genetic disorders can be inherited from parents or acquired throughout a person's lifetime due to various factors such as exposure to certain chemicals or radiation.

Cancer is the correct answer because uncontrolled cell division is a characteristic feature of cancer. Cancer occurs when normal cells undergo genetic mutations that cause them to divide and grow uncontrollably, forming a mass of abnormal cells called a tumor. This unregulated cell division can lead to the spread of cancer cells to other parts of the body, causing further complications and potentially leading to death if left untreated. Therefore, cancer is the most appropriate term to describe uncontrolled cell division.

When two parents that are heterozygous for a trait are crossbred, the genotype of the offspring in terms of dominant and recessive alleles would be 1:2:1. This means that for every one individual with a homozygous dominant genotype, there will be two individuals with a heterozygous genotype, and one individual with a homozygous recessive genotype. This ratio is known as the Mendelian ratio and is commonly observed in genetic crosses involving a single trait.

Both photosynthesis and cellular respiration involve electron transport systems in the membranes of organelles. In photosynthesis, this occurs in the thylakoid membranes of chloroplasts, while in cellular respiration, it occurs in the inner mitochondrial membrane. These electron transport systems play a crucial role in generating ATP, the energy currency of cells. They use the energy from electrons to pump protons across the membrane, creating a gradient that drives ATP synthesis. Therefore, this commonality between photosynthesis and cellular respiration is an important aspect of how both processes generate energy for the cell.

Each enzyme binds with only one type of substrate to catalyze a reaction. Enzymes are highly specific in terms of the substrates they can bind to and react with. This specificity is due to the unique shape and chemical properties of the enzyme's active site, which can only accommodate a specific substrate molecule. This ensures that enzymes catalyze specific reactions by selectively binding with the appropriate substrate.

Glucose is the correct answer because it is the final product of photosynthesis. During the dark phases of photosynthesis, energy from light is stored in the form of chemical bonds in glucose molecules. Glucose is a sugar molecule that plants use as a source of energy and as a building block for other organic compounds. It is an essential fuel for cellular respiration, which releases energy for the plant's metabolic processes.

Mutations are heritable changes in the sequence of nucleotides in DNA. This means that there is a permanent alteration in the DNA sequence that can be passed on to future generations. These changes can occur due to various factors such as errors during DNA replication, exposure to mutagens, or spontaneous changes. Mutations can lead to observable changes in an organism's characteristics or traits, which can have both positive and negative effects on the organism's survival and evolution.

A 9+2 arrangement refers to the structure of cilia. Cilia are tiny, hair-like structures that extend from the surface of cells. They play a crucial role in cell movement and sensory functions. The 9+2 arrangement specifically refers to the arrangement of microtubules within cilia. It consists of nine peripheral microtubule doublets surrounding a central pair of microtubules. This arrangement provides structural support and allows cilia to move in a coordinated manner, facilitating their various functions.

The sequence of nitrogenous bases in nucleotides is the key to DNA storing genetic information that is unique to each individual organism. The arrangement of these bases (adenine, thymine, cytosine, and guanine) in specific order forms the genetic code that determines the characteristics and traits of an organism. This sequence is what makes each individual's DNA unique and is responsible for encoding the instructions for protein synthesis and other biological processes.

Phospholipids are classified as unusual lipids because they contain a polar end. Unlike other lipids, which are typically hydrophobic (repel water), phospholipids have a hydrophilic (attracted to water) head and a hydrophobic tail. This unique structure allows phospholipids to form the basic building blocks of cell membranes. The polar end of phospholipids interacts with water, while the fatty acid tails face inward, creating a barrier that separates the inside of the cell from its external environment. This property is essential for maintaining the integrity and functionality of cell membranes.

ATP is not a molecule that temporarily stores energy in the form of electrons as a hydrogen carrier used in metabolic pathways. Instead, ATP is a molecule that directly stores and transfers energy in cells. It is often referred to as the "energy currency" of the cell, as it provides the energy needed for various cellular processes. NADH, FADH2, and NADPH, on the other hand, are molecules that serve as hydrogen carriers and temporarily store energy in the form of electrons during metabolic pathways.

The cross BbTt and BBtt will result in offspring with the genotypes BbTt, Bbtt, BBTt, and BBtt. Out of these four genotypes, only the genotype BbTt will have both black fur and long tails. Therefore, the proportion of offspring with black fur and long tails is 1 out of 4 possible genotypes, which is equal to 1/4. Simplifying 1/4, we get 4/16. Therefore, the answer is 4/16, which can be further simplified to 1/4 or 6/16.

If a double-stranded DNA molecule contains 30% T, it means that the other complementary strand also contains 30% A since T always pairs with A in DNA. The total percentage of T and A together is 60%. Since DNA is made up of only four nucleotides (A, T, G, C), the remaining percentage must be divided equally between G and C. Therefore, the DNA molecule contains 20% G.

During glycolysis, glucose is broken down into two molecules of pyruvate, producing a small amount of ATP and NADH. NADH is a high-energy molecule that carries electrons to the electron transport chain in cellular respiration, where it is used to generate more ATP. Therefore, NADH is the correct answer as it represents the energy leaving glycolysis in the form of high-energy electrons.

In the Krebs Cycle, energy is released in the form of NADH and FADH2. These molecules are electron carriers that transport high-energy electrons to the electron transport chain, where ATP is ultimately produced. Glucose is the starting molecule for the Krebs Cycle, but it is not the form in which energy is released. ATP is produced through oxidative phosphorylation in the electron transport chain, but it is not a direct product of the Krebs Cycle. Therefore, the correct answer is NADH & FADH2.

The correct answer is "referred to as osmosis." Osmosis is the process by which water molecules move across a cell membrane from an area of lower solute concentration to an area of higher solute concentration. It is a passive process that does not require energy. This movement of water is essential for maintaining the balance of water and solutes inside and outside the cell.

Enzymes decrease the amount of energy that needs to be put into a reaction to start it. They lower the activation energy required for a reaction to occur, making it easier for the reaction to proceed. This is achieved by providing an alternative pathway for the reaction to follow, which has a lower activation energy. As a result, enzymes speed up the rate of reactions without being consumed in the process.

Human males have 24 different types of chromosomes based on size and shape. This is because males have two sex chromosomes, known as X and Y. Each male has one X chromosome and one Y chromosome, making a total of 24 chromosomes. The other options (47, 21, and 13) are incorrect as they do not represent the correct number of chromosomes in human males.

Ribose and deoxyribose sugars are found in all DNA and RNA. These sugars are classified as monosaccharides, which means they are single sugar units. Monosaccharides are the simplest form of carbohydrates and serve as the basic building blocks for more complex carbohydrates like polysaccharides. While proteins are also important biomolecules, they are not directly related to ribose and deoxyribose sugars. Glucose is a different type of monosaccharide and not specifically related to ribose and deoxyribose sugars.

A single gene specifically contains information for the synthesis of a single protein. This means that the gene carries the instructions for the production of a specific protein molecule. Proteins are essential for various biological processes and functions in the body, such as enzyme activity, structural support, and cell signaling. Each gene is responsible for coding the sequence of amino acids that make up a particular protein, and this information is then used by the cell's machinery to produce that specific protein. Therefore, the correct answer is that a single gene contains information for the synthesis of a single protein.

Water has a maximum density at 4°C. This is because as water cools down from higher temperatures, its molecules start to move slower and come closer together, resulting in an increase in density. However, when water cools below 4°C, its molecules start to form a unique structure called a lattice, which causes the density to decrease. Therefore, 4°C is the temperature at which water reaches its maximum density before it starts to expand and become less dense as it freezes.

The structure in the figure to the right is a carbohydrate because it consists of carbon, hydrogen, and oxygen atoms in a specific ratio. Carbohydrates are organic compounds that serve as a source of energy for living organisms. They can exist as monosaccharides (simple sugars), disaccharides (two sugar units), or polysaccharides (long chains of sugar units). The figure likely represents a carbohydrate structure due to its composition and the fact that it is not mentioned to be a lipid, protein, or nucleic acid.

Active transport is the process by which molecules move across cell membranes against their concentration gradient, requiring the use of energy in the form of ATP. This process is necessary when the concentration of a substance is higher inside the cell than outside, and the cell needs to import that substance. Oxygen, being a small molecule, can passively diffuse across cell membranes through simple diffusion. However, in certain situations where the concentration of oxygen is lower outside the cell, active transport may be used to bring oxygen into the cell.

Glycosis is the correct answer because it is the most widespread metabolic pathway that occurs in living organisms and does not require oxygen or organelles. Glycosis is the process by which glucose is broken down into pyruvate, producing a small amount of ATP. It is a fundamental step in cellular respiration and occurs in the cytoplasm of cells. This pathway is essential for energy production in anaerobic conditions or when oxygen is limited.

Cholesterol is a type of lipid that plays important roles in the cell membrane fluidity, synthesis of sex hormones, and absorption of light. It helps maintain the fluidity and integrity of cell membranes by preventing them from becoming too rigid or too fluid. Cholesterol is also a precursor for the synthesis of steroid hormones, such as estrogen and testosterone, which are involved in regulating sexual development and function. Additionally, cholesterol is a component of the retina and is involved in the absorption of light, playing a crucial role in vision.

Photosynthetic pigments such as chlorophyll are responsible for absorbing light energy during photosynthesis. These pigments are located in the chloroplasts of plant cells and are able to capture light energy from the sun. This energy is then used to convert water and carbon dioxide into glucose and oxygen through a series of chemical reactions. Therefore, photosynthetic pigments such as chlorophyll play a crucial role in converting light energy into chemical energy during photosynthesis.

During photosynthesis, chlorophyll molecules in plants absorb light energy and use it to convert water and carbon dioxide into glucose and oxygen. In this process, chlorophyll loses electrons. To replenish the lost electrons and stabilize chlorophyll, new electrons are stripped from water molecules. This process is known as photolysis, where water molecules are split into oxygen, protons, and electrons. The released oxygen is then released into the atmosphere, while the electrons are used to replace the lost ones in chlorophyll, allowing it to continue the process of photosynthesis.

The cells of all the options listed in the question, except for maintaining proper pH of biological fluids, are eukaryotic. Eukaryotic cells have a well-defined nucleus and other membrane-bound organelles, whereas prokaryotic cells do not. Therefore, the correct answer is maintaining proper pH of biological fluids.

All cells originate from previously existing cells. This is known as the principle of cell theory, which states that all living organisms are composed of cells and that cells are the basic unit of life. This principle is supported by scientific evidence and observations, such as the fact that cells can only arise from pre-existing cells through processes like cell division. Therefore, this statement accurately explains why cells are considered the basic unit of life.

The sodium/potassium pump is a common example of active transport because it actively moves sodium ions out of the cell and potassium ions into the cell against their concentration gradients. This process requires energy in the form of ATP and is essential for maintaining the proper balance of these ions inside and outside of the cell.

The reaction ADP + P -> ATP results in the storage of energy in ATP. ATP (adenosine triphosphate) is a high-energy molecule that stores and carries energy within cells. When ADP (adenosine diphosphate) and a phosphate group combine, energy is absorbed and stored in the ATP molecule. This stored energy can then be used to power various cellular processes and do work when needed. Therefore, the correct answer is "Storage of energy in ATP."

During the phases of photosynthesis that require light, ATP is produced for later use. Photosynthesis is a process in which plants convert sunlight, water, and carbon dioxide into glucose (a form of energy) and oxygen. The light-dependent reactions of photosynthesis occur in the thylakoid membrane of the chloroplasts and involve the absorption of light energy by chlorophyll. This energy is used to generate ATP through a series of chemical reactions. ATP is an energy molecule that can be stored and used by the plant for various metabolic processes, such as growth, reproduction, and cellular respiration.

Spontaneous mutations occur as a result of instabilities in DNA. These instabilities can be caused by various factors such as errors during DNA replication, chemical reactions within the cell, or the natural decay of DNA over time. These instabilities can lead to changes in the DNA sequence, resulting in a mutation. Damage to DNA by an outside agent, incomplete gene expression, and alteration of DNA can also cause mutations, but the question specifically asks for the cause of spontaneous mutations, which is instabilities in DNA.

The statement "May develop into mature sperm" is true because meiosis is the process of cell division that produces haploid cells, such as sperm or eggs. These haploid cells have the potential to mature and develop into functional gametes, in this case, sperm. Therefore, the four haploid cells resulting from meiosis can potentially develop into mature sperm.

Osmosis is the movement of water molecules across a semi-permeable membrane from an area of low solute concentration to an area of high solute concentration. This means that osmosis may be related to a high concentration of dissolved molecules.

The correct answer is "Characterizes the cells as haploid." During meiosis, the chromosome number in cells is indeed reduced by half, resulting in haploid cells. This reduction is necessary for sexual reproduction because it ensures that when two haploid cells (gametes) combine during fertilization, the resulting offspring will have the correct number of chromosomes. If the chromosome number was not reduced, the offspring would have double the number of chromosomes, which would lead to genetic abnormalities. Therefore, all of the given options are correct.

Certain compounds that cause a buildup of H+ ions when added to water are referred to as acids. On the other hand, substances that cause a buildup of OH- ions when added to water are referred to as bases. Therefore, the correct answer is acids and bases.