1.
Which of the following is a polymer of amino acids?
Correct Answer
A. Protein
Explanation
Protein is a polymer of amino acids. It is made up of long chains of amino acids that are linked together by peptide bonds. These chains can fold and interact with each other to form complex three-dimensional structures. Proteins are essential for many biological processes and functions in the body, such as enzyme catalysis, cell signaling, and structural support.
2.
Which of the following is a polymer of nucleotides?
Correct Answer
A. Nucleic Acid
Explanation
Nucleic acid is a polymer of nucleotides. Nucleotides are the building blocks of nucleic acids, which include DNA and RNA. They consist of a sugar molecule, a phosphate group, and a nitrogenous base. Nucleic acids are essential for storing and transmitting genetic information in living organisms. Proteins, carbohydrates, and lipids are not polymers of nucleotides.
3.
Which of the following monomers make up a lipid?
Correct Answer
A. Glycerol and fatty acid
Explanation
Lipids are composed of glycerol and fatty acids. Glycerol is a three-carbon alcohol with hydroxyl groups, while fatty acids are long hydrocarbon chains with a carboxyl group at one end. These two monomers combine through dehydration synthesis, forming ester bonds between the hydroxyl groups of glycerol and the carboxyl groups of fatty acids. This combination results in the formation of triglycerides, which are the main components of lipids found in organisms. Therefore, the correct answer is glycerol and fatty acid.
4.
Which of the following is NOT a nucleotide found in DNA?
Correct Answer
C. Uracil
Explanation
Uracil is not a nucleotide found in DNA. DNA is composed of four nucleotides: adenine (A), cytosine (C), guanine (G), and thymine (T). Uracil (U) is found in RNA instead of DNA. RNA uses uracil instead of thymine as one of its nucleotides. Therefore, uracil is the correct answer as it is not a nucleotide found in DNA.
5.
Which of the following is a structural form of carbohydrate?
Correct Answer
A. Cellulose
Explanation
Cellulose is a structural form of carbohydrate because it is a complex polysaccharide made up of glucose molecules linked together in a linear chain. It forms the main structural component of plant cell walls and provides rigidity and support to plants. Starch, on the other hand, is a storage form of carbohydrate found in plants, while enzymes and RNA are not carbohydrates at all.
6.
Atherosclerosis is a disease caused by a build-up of plaque inside arteries. What polymer is the main component of the plaque formation?
Correct Answer
A. Saturated fatty acids
Explanation
Atherosclerosis is a disease characterized by the accumulation of plaque inside arteries. Plaque is primarily composed of cholesterol, fatty substances, cellular waste products, calcium, and fibrin. Saturated fatty acids, which are commonly found in foods like red meat, butter, and full-fat dairy products, have been shown to contribute to the formation of plaque in arteries. Therefore, saturated fatty acids are the main component of plaque formation in atherosclerosis.
7.
In biological systems, proteins are said to be denatured when...
Correct Answer
B. The protein changes shape and becomes non-functional.
Explanation
Proteins are composed of amino acids and have a specific three-dimensional structure that is crucial for their function. When proteins are denatured, their shape is altered, causing them to lose their functional properties. This can be caused by various factors such as heat, pH changes, or exposure to certain chemicals. Denaturation disrupts the protein's structure, leading to the loss of its ability to perform its biological functions effectively. Therefore, the correct answer is that denatured proteins change shape and become non-functional.
8.
The functional group -NH2 is called the ____.
Correct Answer
A. Amino group
Explanation
The functional group -NH2 is called the amino group. This group consists of a nitrogen atom bonded to two hydrogen atoms. It is commonly found in organic compounds such as amino acids, which are the building blocks of proteins. The amino group is important in various biological processes and plays a crucial role in the structure and function of proteins.
9.
How many amino acids are found in humans?
Correct Answer
C. 20
Explanation
There are 20 amino acids found in humans. Amino acids are the building blocks of proteins and play a crucial role in various biological processes. They are essential for the synthesis of proteins, enzymes, hormones, and neurotransmitters. These 20 amino acids are classified into two categories: essential amino acids, which cannot be synthesized by the body and must be obtained through diet, and nonessential amino acids, which can be synthesized by the body.
10.
Which of the following describes DNA?
Correct Answer
C. It controls the production of proteins.
Explanation
DNA, or deoxyribonucleic acid, is a molecule that contains the genetic instructions for the development and functioning of all living organisms. It is composed of nucleotides, which consist of a sugar molecule (deoxyribose), a phosphate group, and a nitrogenous base (adenine, thymine, cytosine, or guanine). DNA controls the production of proteins through a process called protein synthesis. This involves the transcription of DNA into messenger RNA (mRNA), which is then translated into proteins. Therefore, the correct answer is that DNA controls the production of proteins.
11.
Organic compounds always contain the element ____.
Correct Answer
A. Carbon
Explanation
Organic compounds are defined as compounds that contain carbon atoms bonded to hydrogen atoms. Carbon is the essential element in organic compounds as it forms strong covalent bonds with other elements, allowing for the formation of complex and diverse organic molecules. Nitrogen and oxygen are also commonly found in organic compounds, but carbon is always present. "Organium" is not a valid element and is not related to organic compounds.
12.
Which of the following is NOT true of water?
Correct Answer
C. It can diffuse through lipids easily.
Explanation
Water cannot diffuse through lipids easily because lipids are nonpolar molecules, while water is a polar molecule. Polar molecules like water are attracted to other polar molecules and repelled by nonpolar molecules. Lipids, being nonpolar, do not interact well with water and therefore water cannot easily pass through lipid membranes.
13.
There are literally hundreds of thousands of different organic molecules. Which statement best explains how this is possible?
Correct Answer
B. Carbon is unique in that it can make four chemical bonds.
Explanation
Carbon is unique in that it can make four chemical bonds. This allows it to form a wide variety of organic molecules by bonding with other elements such as hydrogen, oxygen, nitrogen, and sulfur. The ability to form multiple bonds gives carbon the flexibility to create complex and diverse molecular structures, leading to the vast number of organic molecules found in nature.
14.
If we find life elsewhere in the universe it is likely to look exactly like life on Earth because there is a limited number of proteins that can be formed.
Correct Answer
B. False
Explanation
The given statement is false. While it is true that there is a limited number of proteins that can be formed, it does not necessarily mean that life elsewhere in the universe would look exactly like life on Earth. Life on other planets could have different biochemistries and use different building blocks for their proteins. Additionally, the conditions and environments on other planets may be vastly different from Earth, leading to the evolution of different forms of life. Therefore, it is not accurate to assume that life elsewhere in the universe would be identical to life on Earth.
15.
The specific chemical that an enzyme will act on is called a(n) ...
Correct Answer
A. Substrate.
Explanation
An enzyme is a type of protein that acts as a catalyst in biochemical reactions. It helps to speed up the reaction by lowering the activation energy required. The specific chemical that an enzyme acts on is called a substrate. The enzyme binds to the substrate at its active site, forming an enzyme-substrate complex. The enzyme then catalyzes the conversion of the substrate into a product. Therefore, the correct answer is substrate.
16.
Which phrase best describes the effect of a catalyst on a chemical reaction?
Correct Answer
C. Decreases the activation energy
Explanation
A catalyst is a substance that speeds up a chemical reaction by lowering the activation energy required for the reaction to occur. By decreasing the activation energy, a catalyst allows the reaction to proceed at a faster rate, without being consumed in the process. Therefore, the correct answer is "decreases the activation energy."
17.
What type of polymer is an enzyme?
Correct Answer
A. Protein
Explanation
Enzymes are a type of protein. Proteins are large, complex molecules made up of amino acids. Enzymes are biological catalysts that speed up chemical reactions in living organisms. They play a crucial role in various physiological processes and are involved in almost all cellular activities. Enzymes have specific shapes that allow them to bind to specific substrates and facilitate chemical reactions. Therefore, the correct answer is protein.
18.
What part is labeled B?
Correct Answer
B. Ribose Sugar
Explanation
The part labeled B in this question is the Ribose Sugar. This is because ribose sugar is one of the three components of a nucleotide, which is the building block of nucleic acids like DNA and RNA. The other two components of a nucleotide are a phosphate group and a nitrogen base. In this case, the question is asking specifically about the part labeled B, and out of the given options, the Ribose Sugar is the correct answer.
19.
What part is labeled C?
Correct Answer
C. Nitrogen Base
Explanation
In the context of nucleotides, the part labeled C refers to the nitrogen base. Nitrogen bases are the molecules that make up the "rungs" of the DNA ladder and determine the genetic information encoded in the DNA sequence. There are four types of nitrogen bases: adenine (A), thymine (T), cytosine (C), and guanine (G). In this question, the correct answer is C, which represents the nitrogen base.
20.
What part is labeled A?
Correct Answer
A. pHospHate
Explanation
The correct answer for the part labeled A is "Phosphate." Phosphate is an essential component of a nucleotide, which is the basic building block of nucleic acids like DNA and RNA. It consists of a phosphate group, a sugar molecule (ribose or deoxyribose), and a nitrogenous base. The phosphate group plays a crucial role in the structure and function of nucleic acids, as it forms the backbone of the DNA or RNA molecule, providing stability and allowing for the attachment of other nucleotides.
21.
This is a diagram of a monomer called a ___.
Correct Answer
D. Nucleotide
Explanation
The diagram represents a monomer, which is a single unit that can combine with other units to form a larger molecule. In this case, the diagram includes a phosphate group, a ribose sugar, and a nitrogen base. These three components are characteristic of a nucleotide, which is the monomer unit that makes up nucleic acids such as DNA and RNA. Therefore, the correct answer is "Nucleotide".
22.
This is a diagram of a monomer that is used to build ___.
Correct Answer
C. Nucleic Acids
Explanation
The diagram represents a monomer that is used to build nucleic acids. Nucleic acids are polymers made up of repeating units called nucleotides, and the diagram likely shows one such nucleotide. Nucleic acids, such as DNA and RNA, play a crucial role in storing and transmitting genetic information in living organisms. They are composed of a sugar (represented by the diagram), a phosphate group, and a nitrogenous base. Therefore, based on the given information, the correct answer is nucleic acids.
23.
Which of the following is not one of the top elements in the body?
Correct Answer
D. Calcium
Explanation
Calcium is not one of the top elements in the body because it is not one of the most abundant elements found in the human body. The top elements in the body include carbon, hydrogen, nitrogen, and oxygen, which make up the majority of the body's composition. Calcium, although important for bone health and other bodily functions, is present in much smaller quantities compared to these other elements.
24.
Which of the following is a "4%" element in the body?
Correct Answer
B. Calcium
Explanation
Calcium is a "4%" element in the body because it makes up approximately 4% of the total body weight. It is an essential mineral that plays a crucial role in maintaining strong bones and teeth, as well as aiding in muscle function, nerve transmission, and blood clotting. Calcium is primarily stored in the bones and teeth, but it is also found in the bloodstream, where it is tightly regulated to maintain proper levels for bodily functions.
25.
Which of the following trace elements can prevent goiters?
Correct Answer
B. Iodine
Explanation
Iodine is the correct answer because it is a trace element that is essential for the production of thyroid hormones. Goiters are often caused by a deficiency of iodine, which leads to an enlargement of the thyroid gland. Therefore, consuming sufficient amounts of iodine can prevent goiters from occurring.
26.
What is the main function of the Krebs cycle?
Correct Answer
C. Producing molecules that carry high-energy electrons to the electron transport chain
Explanation
The Krebs cycle, also known as the citric acid cycle, is a series of chemical reactions that occur in the mitochondria of cells. Its main function is to produce molecules that carry high-energy electrons to the electron transport chain. During the Krebs cycle, carbon dioxide, NADH, and FADH2 are produced as byproducts. These molecules carry high-energy electrons that are used in the electron transport chain to produce ATP, the energy currency of the cell. Therefore, the correct answer is "producing molecules that carry high-energy electrons to the electron transport chain."
27.
What is the function of oxygen in cellular respiration?
Correct Answer
B. To pick up electrons at the end of the electron transport chain
Explanation
Oxygen in cellular respiration serves the function of picking up electrons at the end of the electron transport chain. In this process, electrons are passed along the chain and eventually combine with oxygen to form water. This final step allows for the regeneration of electron carriers and the continuation of ATP production. Without oxygen, the electron transport chain would not be able to function properly, leading to a decrease in ATP production and potentially disrupting cellular respiration.
28.
Plant cells do not conduct cellular respiration.
Correct Answer
B. False
Explanation
Plant cells do conduct cellular respiration. Cellular respiration is the process by which cells break down glucose to produce energy in the form of ATP. In plant cells, this process occurs in the mitochondria, just like in animal cells. Plant cells require energy for various metabolic activities, growth, and reproduction, which is why they undergo cellular respiration. Therefore, the statement that plant cells do not conduct cellular respiration is false.
29.
What is the term for an organism that makes its own source of chemical energy?
Correct Answer
B. Producer
Explanation
A producer is an organism that has the ability to produce its own source of chemical energy through photosynthesis or chemosynthesis. This process involves converting sunlight or inorganic compounds into organic compounds, such as glucose, which can be used as a source of energy. Producers play a crucial role in ecosystems by providing energy for other organisms through the food chain.
30.
Which stage of the cell cycle is illustrated on the right?
Correct Answer
B. Cytokinesis
Explanation
The stage of the cell cycle illustrated on the right is cytokinesis. Cytokinesis is the final stage of the cell cycle, where the cytoplasm divides and two daughter cells are formed. This process ensures that each daughter cell receives a complete set of genetic material and organelles. In the given image, if the cell is seen dividing into two separate cells with a visible separation between them, it indicates that cytokinesis is occurring.
31.
Which phrase best describes the electron transport chain in photosynthesis?
Correct Answer
C. A series of proteins located in the thylakoid membrane
Explanation
The electron transport chain in photosynthesis is a series of proteins located in the thylakoid membrane. These proteins are responsible for transferring electrons and generating a proton gradient, which is used to produce ATP during the light-dependent reactions of photosynthesis. The thylakoid membrane is where the light-harvesting pigments are located, and it is the site of the electron transport chain. Therefore, the phrase "a series of proteins located in the thylakoid membrane" best describes the electron transport chain in photosynthesis.
32.
The process by which plants use sunlight to make glucose is called ___.
Correct Answer
A. pHotosynthesis
Explanation
Photosynthesis is the correct answer because it is the process by which plants convert sunlight, water, and carbon dioxide into glucose and oxygen. During photosynthesis, plants use chlorophyll in their leaves to capture sunlight and convert it into chemical energy that is stored in the form of glucose. This process is essential for the survival of plants and is responsible for producing the oxygen that we breathe. Cellular respiration, the cell cycle, and mitosis are unrelated processes that do not involve the conversion of sunlight into glucose.
33.
Which of the following takes place in the light-dependent reactions of photosynthesis?
Correct Answer
B. Energy is captured.
Explanation
In the light-dependent reactions of photosynthesis, energy is captured from sunlight by chlorophyll molecules in the chloroplasts of plant cells. This captured energy is then used to convert water and carbon dioxide into ATP (adenosine triphosphate) and NADPH (nicotinamide adenine dinucleotide phosphate), which are energy-rich molecules used in the subsequent dark reactions of photosynthesis to produce sugars. Therefore, the correct answer is "Energy is captured."
34.
Oxygen is used during glycolysis.
Correct Answer
B. False
Explanation
Oxygen is not used during glycolysis. Glycolysis is the first step in cellular respiration, and it occurs in the cytoplasm of cells. It is an anaerobic process, meaning it does not require oxygen. Oxygen is only used in the later stages of cellular respiration, specifically during the citric acid cycle and the electron transport chain, which take place in the mitochondria. Therefore, the statement that oxygen is used during glycolysis is false.
35.
How many ATP are formed from one molecule of glucose during cellular respiration?
Correct Answer
C. 38
Explanation
During cellular respiration, one molecule of glucose produces a total of 38 ATP. This process involves several steps, including glycolysis, the Krebs cycle, and the electron transport chain. In glycolysis, two ATP are produced directly. The Krebs cycle then produces two more ATP. The majority of ATP, however, is generated during the electron transport chain, where the energy stored in NADH and FADH2 is used to create a proton gradient across the inner mitochondrial membrane. This gradient is then used by ATP synthase to produce a total of 34 ATP. Therefore, the correct answer is 38.
36.
In the light-independent reactions of photosynthesis,
Correct Answer
A. Carbon dioxide enters the Calvin cycle and sugars are made.
Explanation
In the light-independent reactions of photosynthesis, carbon dioxide enters the Calvin cycle and sugars are made. This is because during the Calvin cycle, carbon dioxide molecules are combined with a five-carbon molecule called RuBP (ribulose-1,5-bisphosphate) to form an unstable six-carbon molecule. This molecule then breaks down into two molecules of PGA (3-phosphoglycerate), which are then converted into G3P (glyceraldehyde-3-phosphate) with the help of ATP and NADPH. G3P can then be used to produce glucose and other sugars, which are essential for the plant's energy storage and growth.
37.
Where do the hydrogen ions for the photosystems of the light-dependent reactions come from?
Correct Answer
D. Water
Explanation
In the light-dependent reactions of photosynthesis, the hydrogen ions for the photosystems come from water. During the process of photosynthesis, water molecules are split through a process called photolysis, releasing oxygen, electrons, and hydrogen ions. The electrons are used by the photosystems to generate ATP and NADPH, while the hydrogen ions contribute to the formation of a proton gradient that drives ATP synthesis. This process is essential for the conversion of light energy into chemical energy, allowing plants to produce glucose and oxygen.
38.
The function of the light-dependent reactions is to
Correct Answer
B. Capture and transfer energy.
Explanation
The light-dependent reactions in photosynthesis involve capturing and transferring energy from sunlight. During these reactions, light energy is absorbed by chlorophyll molecules in the thylakoid membranes of chloroplasts. This energy is then used to generate high-energy molecules such as ATP and NADPH, which are essential for the subsequent dark reactions that produce sugars. Therefore, the function of the light-dependent reactions is to capture and transfer energy, enabling the synthesis of organic compounds.
39.
The main light-absorbing molecules found in plant leaves are called
Correct Answer
C. ChloropHyll
Explanation
Chlorophyll is the correct answer because it is the main light-absorbing pigment found in plant leaves. It is responsible for capturing sunlight during photosynthesis and converting it into energy for the plant. Chloroplasts are the organelles in plant cells where photosynthesis occurs, but they contain chlorophyll. Thylakoids are membrane structures within chloroplasts where the light-dependent reactions of photosynthesis take place. Grana are stacks of thylakoids. Therefore, while chloroplasts, thylakoids, and grana are all involved in photosynthesis, chlorophyll is the specific molecule that absorbs light.
40.
Animal cells are the only type of cell that contains mitochondria.
Correct Answer
B. False
Explanation
Animal cells are not the only type of cell that contains mitochondria. Mitochondria are present in both animal and plant cells. They are responsible for producing energy in the form of ATP through cellular respiration. Plant cells also contain mitochondria as they require energy for various metabolic processes. Therefore, the statement that animal cells are the only type of cell that contains mitochondria is false.
41.
Which of the following statements best describes the process of photosynthesis?
Correct Answer
D. Chloroplasts absorb sunlight and store chemical energy.
Explanation
The process of photosynthesis is best described by the statement "Chloroplasts absorb sunlight and store chemical energy." Photosynthesis is the process by which plants, algae, and some bacteria convert sunlight, water, and carbon dioxide into glucose and oxygen. Chloroplasts, which contain the pigment chlorophyll, are the organelles responsible for capturing sunlight and converting it into chemical energy in the form of glucose. This statement accurately describes the role of chloroplasts in photosynthesis.
42.
What are the products of photosynthesis?
Correct Answer
B. Glucose and oxygen
Explanation
Photosynthesis is the process by which plants convert sunlight, carbon dioxide, and water into glucose (a sugar) and oxygen. Glucose is a source of energy for the plant, while oxygen is released into the atmosphere as a byproduct. Therefore, the correct answer is "glucose and oxygen."
43.
In the diagram to the right, the structure labeled D is the ___.
Correct Answer
C. Granum
Explanation
In the given diagram, the structure labeled D is the granum. The granum is a stack of thylakoid membranes found in the chloroplasts of plant cells. These thylakoid membranes contain chlorophyll, which is responsible for capturing light energy during photosynthesis. The granum plays a crucial role in the light-dependent reactions of photosynthesis, where the captured light energy is used to convert water and carbon dioxide into oxygen and glucose.
44.
In the diagram to the right, the structure labeled E is the ___.
Correct Answer
D. Thylakoid membranes
Explanation
In the given diagram, the structure labeled E appears to be a network of interconnected flattened sacs, which is characteristic of thylakoid membranes. Thylakoid membranes are found within chloroplasts and are responsible for carrying out the light-dependent reactions of photosynthesis. They contain pigments such as chlorophyll, which capture light energy and convert it into chemical energy. The stroma is the fluid-filled space surrounding the thylakoid membranes, while the granum refers to a stack of thylakoid membranes. Therefore, the correct answer is thylakoid membranes.
45.
The purpose of the light reactions is to___.
Correct Answer
A. Make ATP and NADpH for use in the Calvin cycle
Explanation
The purpose of the light reactions is to make ATP and NADPH for use in the Calvin cycle. During the light reactions, light energy is absorbed by chlorophyll and converted into chemical energy in the form of ATP and NADPH. These energy-rich molecules are then used in the Calvin cycle, where carbon dioxide is converted into glucose. Oxygen is produced as a byproduct of the light reactions, but its main purpose is not to make oxygen itself. The primary goal of the light reactions is to generate ATP and NADPH, which are essential for the production of glucose.
46.
What is the term for the jelly-like substance that is contained inside the cell membrane?
Correct Answer
A. Cytoplasm
Explanation
The correct answer is cytoplasm. Cytoplasm is the jelly-like substance that is contained inside the cell membrane. It is a semi-fluid substance that fills the cell and surrounds the organelles. It contains various molecules, such as proteins, enzymes, and nutrients, which are necessary for cellular processes to occur. The cytoplasm also acts as a medium for transporting materials within the cell and providing support and structure.
47.
Some cells live their entire lives without going through mitosis. These cells are said to be in ___.
Correct Answer
A. G zero
Explanation
Some cells do not undergo mitosis and remain in a non-dividing state called G zero. In this phase, cells temporarily or permanently exit the cell cycle and stop dividing. They may stay in this phase for a long time or indefinitely, performing their specialized functions without the need for replication. This allows for cell differentiation and the maintenance of specialized tissues in the body. The G zero phase is essential for the proper functioning and stability of multicellular organisms.
48.
All of the following are stages of Interphase except ___.
Correct Answer
D. M
Explanation
Interphase is the stage in the cell cycle where the cell prepares for cell division. It consists of three stages: G1, S, and G2. During G1, the cell grows and carries out its normal functions. In the S stage, DNA replication occurs. G2 is the stage where the cell prepares for division by synthesizing proteins and organelles. The M stage, or mitosis, is the actual process of cell division where the cell's nucleus divides into two daughter nuclei. Therefore, M is not a stage of Interphase.
49.
Which of the following is a characteristic of S phase?
Correct Answer
D. DNA is replicated.
Explanation
The S phase of the cell cycle is the phase where DNA replication occurs. During this phase, the cell synthesizes a copy of its DNA in preparation for cell division. This is an essential step to ensure that each daughter cell receives a complete set of genetic information. The other options mentioned, such as cell growth, preparation for mitosis, and nuclear membrane reforms, are not specific to the S phase and can occur at different stages of the cell cycle.
50.
Which stage of mitosis is illustrated on the right?
Correct Answer
D. AnapHase
Explanation
The stage of mitosis illustrated on the right is anaphase. In anaphase, the sister chromatids separate and move towards opposite ends of the cell. This is facilitated by the shortening of microtubules and the pulling force exerted by the spindle fibers. The chromosomes are clearly shown moving away from each other in the image, indicating the characteristic feature of anaphase.