Principles Of Biology - Phospholipid Quiz

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Principles Of Biology - Phospholipid Quiz - Quiz

This quiz covers the materials in lecture handouts 5, 6, and 8. This quiz mainly covers these topics: phospholipids, enzymes, and types of transport.


Questions and Answers
  • 1. 

    If it is perfectly symmetrical than it is ______?

    • A.

      Nonpolar

    • B.

      Polar

    Correct Answer
    A. Nonpolar
    Explanation
    If an object or molecule is perfectly symmetrical, it means that it has equal distribution of its charge or elements around its center. In chemistry, a nonpolar molecule is one in which the distribution of charge is symmetric, meaning there is no separation of positive and negative charges. Therefore, if an object or molecule is perfectly symmetrical, it would be considered nonpolar.

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  • 2. 

    The cell membrane is mostly lipid so it is _____?

    • A.

      Nonpolar

    • B.

      Polar

    Correct Answer
    A. Nonpolar
    Explanation
    The cell membrane is mostly composed of lipids, specifically phospholipids, which have a hydrophilic (water-loving) head and a hydrophobic (water-fearing) tail. This arrangement creates a bilayer structure where the hydrophobic tails face inward, away from the water-based environment both inside and outside the cell. Since lipids are nonpolar molecules, the cell membrane is also nonpolar.

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  • 3. 

    What crosses the cell membrane without the help of a protein?

    • A.

      Polar substances

    • B.

      Nonpolar substances

    Correct Answer
    B. Nonpolar substances
    Explanation
    Nonpolar substances can cross the cell membrane without the help of a protein. The cell membrane is composed of a phospholipid bilayer, which has a hydrophilic (water-loving) outer layer and a hydrophobic (water-repelling) inner layer. Nonpolar substances, which are hydrophobic, can easily pass through the hydrophobic interior of the cell membrane. On the other hand, polar substances, which are hydrophilic, cannot pass through the hydrophobic core of the membrane and require the assistance of proteins to facilitate their transport across the membrane.

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  • 4. 

    What letters are short for Adenosine Triphosphate?

    Correct Answer
    ATP
    Explanation
    ATP is the abbreviation for Adenosine Triphosphate. Adenosine Triphosphate is a molecule that stores and releases energy in living cells. It is often referred to as the "energy currency" of the cell because it provides the energy needed for various cellular processes. The molecule consists of three phosphate groups, a ribose sugar, and an adenine base. The high-energy bonds between the phosphate groups are easily broken, releasing energy that can be used by the cell.

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  • 5. 

    Facilitated diffusion requires ATP.

    • A.

      True

    • B.

      False

    Correct Answer
    B. False
    Explanation
    Facilitated diffusion is a type of passive transport that does not require ATP (adenosine triphosphate) energy. It involves the movement of molecules across a cell membrane with the help of specific transport proteins. These proteins act as channels or carriers to facilitate the movement of substances down their concentration gradient. Unlike active transport processes, facilitated diffusion does not require the input of energy from ATP. Therefore, the statement that facilitated diffusion requires ATP is incorrect.

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  • 6. 

    Integral proteins are required for active transport using vesicles.

    • A.

      True

    • B.

      False

    Correct Answer
    B. False
    Explanation
    Integral proteins are not required for active transport using vesicles. Active transport using vesicles is mediated by a different type of protein called transport proteins or carrier proteins. These proteins bind to specific molecules or ions and undergo conformational changes to transport them across the cell membrane. Integral proteins, on the other hand, are involved in various other functions such as cell adhesion, signal transduction, and structural support. Therefore, the correct answer is false.

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  • 7. 

    Nonpolar molecules cross the cell membrane from an area of higher concentration to an area of lower concentration via ________? (multiple answers)

    • A.

      Facilitated diffusion

    • B.

      Simple diffusion

    • C.

      Passive transport

    • D.

      Active transport

    Correct Answer(s)
    B. Simple diffusion
    C. Passive transport
    Explanation
    Nonpolar molecules are able to cross the cell membrane through simple diffusion, which is a passive transport process. In simple diffusion, molecules move from an area of higher concentration to an area of lower concentration without the need for any energy input. This occurs because nonpolar molecules can freely pass through the lipid bilayer of the cell membrane due to their hydrophobic nature. Therefore, both simple diffusion and passive transport accurately describe the movement of nonpolar molecules across the cell membrane.

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  • 8. 

    Oxygen crosses the cell membrane via ______?(multiple answers)

    • A.

      Passive transport

    • B.

      Active transport

    • C.

      Facilitated diffusion

    • D.

      Simple diffusion

    Correct Answer(s)
    A. Passive transport
    D. Simple diffusion
    Explanation
    Oxygen crosses the cell membrane through passive transport, specifically through a process called simple diffusion. In simple diffusion, molecules move from an area of higher concentration to an area of lower concentration, without the need for energy or assistance from transport proteins. Since oxygen molecules are small and nonpolar, they can easily diffuse across the lipid bilayer of the cell membrane. Therefore, both passive transport and simple diffusion accurately describe how oxygen molecules move across the cell membrane.

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  • 9. 

    K+ moves from an area of high concentration to low concentration via ______?(multiple answers)

    • A.

      Facilitated diffusion

    • B.

      Simple diffusion

    • C.

      Active transport

    • D.

      Passive transport

    Correct Answer(s)
    A. Facilitated diffusion
    C. Active transport
    Explanation
    Facilitated diffusion is a type of passive transport where molecules move across the cell membrane with the help of transport proteins. In this process, K+ ions move from an area of high concentration to low concentration without the need for energy. On the other hand, active transport requires energy and moves molecules against their concentration gradient, from low to high concentration. Therefore, K+ ions do not move via active transport.

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  • 10. 

    K+ moves from an area of low concentration to high concentration via ______?(multiple answers)

    • A.

      Simple diffusion

    • B.

      Facilitated diffusion

    • C.

      Active transport

    • D.

      Passive transport

    Correct Answer(s)
    B. Facilitated diffusion
    D. Passive transport
    Explanation
    Facilitated diffusion and passive transport are both correct answers because they both describe the movement of K+ from an area of low concentration to high concentration without the input of energy. Facilitated diffusion involves the use of protein channels or carriers to facilitate the movement of molecules across the cell membrane, while passive transport refers to the movement of molecules down their concentration gradient without the need for energy. Active transport, on the other hand, requires the input of energy to move molecules against their concentration gradient. Simple diffusion is not the correct answer because it refers to the movement of molecules directly through the phospholipid bilayer without the need for protein channels or carriers.

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  • 11. 

    A white blood cell would engulf a bacterium using what specific type of transport?

    • A.

      Passive transport using osmosis

    • B.

      Active transport using pumps

    • C.

      Active transport using vesicles

    Correct Answer
    C. Active transport using vesicles
    Explanation
    White blood cells use a process called phagocytosis to engulf and destroy bacteria. This process involves the cell extending its membrane around the bacterium and forming a vesicle, which is then transported to the lysosome for digestion. This is an example of active transport using vesicles because the cell actively engulfs the bacterium and transports it within a vesicle.

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  • 12. 

    All types of transport require a membrane.

    • A.

      True

    • B.

      False

    Correct Answer
    B. False
    Explanation
    This statement is false because not all types of transport require a membrane. While some forms of transport, such as passive diffusion, do require a membrane for molecules to move across, there are other types of transport, such as active transport or facilitated diffusion, that can occur without the need for a membrane. Therefore, the statement is not true for all types of transport.

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  • 13. 

    Steroids cross the cell membrane via _______.

    • A.

      Lipids- passive transport- simple diffusion

    • B.

      Lipids- active transport- facilitated diffusion

    • C.

      Lipids- passive transport- osmosis

    Correct Answer
    A. Lipids- passive transport- simple diffusion
    Explanation
    Steroids are lipid molecules that are able to passively diffuse across the cell membrane. Passive transport refers to the movement of molecules across the membrane without the use of energy. Simple diffusion is a type of passive transport where molecules move from an area of high concentration to an area of low concentration. Since steroids are lipid-soluble, they can easily dissolve in the lipid bilayer of the cell membrane and diffuse through it without the need for any transport proteins or energy expenditure. Therefore, the correct answer is lipids- passive transport- simple diffusion.

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  • 14. 

    Anything that has a charge will cross the cell membrane via facilitated diffusion.

    • A.

      True

    • B.

      False

    Correct Answer
    B. False
    Explanation
    The statement is not true because not everything that has a charge will cross the cell membrane via facilitated diffusion. Facilitated diffusion is a passive process that requires the assistance of specific transport proteins to move charged molecules across the cell membrane. However, not all charged molecules can be transported through these proteins. Some charged molecules may require active transport mechanisms or other specialized transport proteins to cross the cell membrane. Therefore, the statement is false.

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  • 15. 

    All molecules using passive transport move along their concentration gradient.

    • A.

      True

    • B.

      False

    Correct Answer
    A. True
    Explanation
    Passive transport is a type of cellular transport where molecules move across the cell membrane without the need for energy input. This movement occurs along the concentration gradient, which is the difference in concentration of a substance between two areas. In passive transport, molecules move from an area of higher concentration to an area of lower concentration until equilibrium is reached. Therefore, all molecules using passive transport do indeed move along their concentration gradient, making the statement true.

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  • 16. 

    Osmosis always refers to the movement of what across the membrane?

    Correct Answer
    water
    Explanation
    Osmosis is a process where water molecules move across a selectively permeable membrane from an area of lower solute concentration to an area of higher solute concentration. This movement of water helps to equalize the concentration of solutes on both sides of the membrane. Therefore, the correct answer is water.

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  • 17. 

    Active transport always uses pumps.

    • A.

      True

    • B.

      False

    Correct Answer
    B. False
    Explanation
    Active transport does not always use pumps. While pumps are one mechanism that can be involved in active transport, there are other methods as well. Active transport refers to the movement of molecules or ions against their concentration gradient, requiring the input of energy. This can be achieved through various mechanisms such as carrier proteins, vesicular transport, or even through the use of ATP directly. Therefore, it is not accurate to say that active transport always uses pumps.

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  • 18. 

    Active transport never moves anything along its concentration gradient.

    • A.

      True

    • B.

      False

    Correct Answer
    A. True
    Explanation
    Active transport is a process that requires the use of energy to move molecules or ions across a cell membrane against their concentration gradient. This means that active transport moves substances from an area of lower concentration to an area of higher concentration. Therefore, the statement "Active transport never moves anything along its concentration gradient" is true, as active transport always works against the concentration gradient.

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  • 19. 

    When you breathe in oxygen it crosses from your alveoli into your blood via _______.(multiple answers)

    • A.

      Passive transport

    • B.

      Active transport

    • C.

      Simple diffusion

    • D.

      Facilitated diffusion

    Correct Answer(s)
    A. Passive transport
    C. Simple diffusion
    Explanation
    Oxygen crosses from the alveoli into the blood through passive transport and simple diffusion. Passive transport refers to the movement of molecules across a membrane without the use of energy, and simple diffusion is a type of passive transport where molecules move from an area of higher concentration to an area of lower concentration. In this case, oxygen moves from the alveoli, where its concentration is higher, into the blood, where its concentration is lower, through simple diffusion.

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  • 20. 

    Lipids are generally _______.

    • A.

      Hydrophobic

    • B.

      Hydrophilic

    Correct Answer
    A. HydropHobic
    Explanation
    Lipids are generally hydrophobic because they consist of nonpolar molecules that do not dissolve in water. This is due to the presence of long hydrocarbon chains in lipids, which are composed of carbon and hydrogen atoms. These hydrophobic chains repel water molecules and are insoluble in water. Lipids play important roles in storing energy, providing insulation, and forming cell membranes.

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  • 21. 

    Sometimes one end of a lipid is hydro____ while the other end is hydro____.

    Correct Answer
    phobic philic
    philic phobic
    Explanation
    Lipids are molecules that have a hydrophobic (water-repelling) end and a hydrophilic (water-attracting) end. This arrangement is due to the unique structure of lipids, which consists of a polar head (hydrophilic) and a nonpolar tail (hydrophobic). The hydrophobic end avoids water and interacts with other nonpolar molecules, while the hydrophilic end interacts with water and other polar molecules. Therefore, lipids have a phobic philic (hydrophobic hydrophilic) arrangement, with one end being hydrophobic and the other end being hydrophilic.

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  • 22. 

    Phospholipids are specialized lipids. They have a _______ group at one end, which makes that end hydrophilic. The other end remains hydrophobic.

    Correct Answer
    phosphate
    Explanation
    Phospholipids are composed of a phosphate group at one end, which is responsible for making that end hydrophilic. This means that it has an affinity for water and can dissolve in it. On the other hand, the other end of the phospholipid molecule is hydrophobic, meaning it repels water and cannot dissolve in it. This unique structure of phospholipids allows them to form the basic building blocks of cell membranes, as they can arrange themselves in a bilayer with their hydrophilic heads facing the watery environment and their hydrophobic tails facing each other.

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  • 23. 

    Glycerol has only ____ carbons.(how many)

    Correct Answer
    3
    Explanation
    Glycerol is a trihydric alcohol, meaning it has three hydroxyl groups (-OH). Each hydroxyl group is attached to a carbon atom, so glycerol has three carbon atoms. Therefore, the correct answer is 3.

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  • 24. 

    A phospholipid has a hydrophilic head and only ___ fatty acid tails.(how many)

    Correct Answer
    2
    Explanation
    A phospholipid has a hydrophilic head and only 2 fatty acid tails. The hydrophilic head of a phospholipid is attracted to water molecules, while the fatty acid tails are hydrophobic and repel water. This unique structure allows phospholipids to form a bilayer in cell membranes, with the hydrophilic heads facing the aqueous environment both inside and outside the cell, and the hydrophobic tails sandwiched in between. The presence of 2 fatty acid tails in a phospholipid is crucial for the formation and stability of the phospholipid bilayer.

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  • 25. 

    What are the monomers of nucleic acids?

    Correct Answer
    Nucleotides
    Explanation
    Nucleic acids are polymers made up of repeating units called monomers. The monomers of nucleic acids are nucleotides. Nucleotides consist of three components: a sugar molecule (ribose or deoxyribose), a phosphate group, and a nitrogenous base (adenine, cytosine, guanine, or thymine/uracil). These nucleotides are linked together through phosphodiester bonds to form the backbone of DNA and RNA molecules. Therefore, nucleotides are the building blocks of nucleic acids.

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  • 26. 

    What are the 3 structures of a nucleotide?(multiple answers)

    • A.

      5 carbon sugar

    • B.

      Nitrogenous base

    • C.

      Phosphate group

    • D.

      Carboxyl group

    • E.

      Amino acid base

    Correct Answer(s)
    A. 5 carbon sugar
    B. Nitrogenous base
    C. pHospHate group
    Explanation
    The three structures of a nucleotide are a 5 carbon sugar, a nitrogenous base, and a phosphate group. These three components make up the basic building blocks of nucleic acids, such as DNA and RNA. The 5 carbon sugar, also known as a pentose sugar, forms the backbone of the nucleotide. The nitrogenous base can be adenine, thymine, cytosine, guanine, or uracil, depending on whether it is DNA or RNA. The phosphate group is responsible for linking the nucleotides together, forming the backbone of the nucleic acid chain.

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  • 27. 

    What is the other term for 5 carbon sugar?

    Correct Answer(s)
    pentose
    Explanation
    The other term for a 5 carbon sugar is pentose.

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  • 28. 

    How many strands does RNA have?

    Correct Answer(s)
    1
    Explanation
    RNA typically consists of a single strand, while DNA has a double helix structure consisting of two strands. Therefore, the correct answer is 1.

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  • 29. 

    How many strands does DNA have?

    Correct Answer(s)
    2
    Explanation
    DNA, or deoxyribonucleic acid, is a double-stranded molecule that consists of two long strands twisted around each other in a double helix structure. Each strand is made up of a series of nucleotides, which are the building blocks of DNA. The two strands are held together by hydrogen bonds between complementary nucleotide bases. Therefore, the correct answer is 2, as DNA consists of two strands.

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  • 30. 

    What is the nitrogenous base DNA has that RNA does not have?

    Correct Answer(s)
    Thymine
    Explanation
    DNA contains the nitrogenous base Thymine, which is not present in RNA. RNA instead contains the nitrogenous base Uracil. Thymine and Uracil are structurally similar, but Thymine has a methyl group, while Uracil does not. This difference in base composition is what distinguishes DNA from RNA.

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  • 31. 

    What are the nitrogenous bases of RNA?(multiple answers)

    • A.

      Adenine

    • B.

      Thymine

    • C.

      Uracil

    • D.

      Guanine

    • E.

      Cytosine

    Correct Answer(s)
    A. Adenine
    C. Uracil
    D. Guanine
    E. Cytosine
    Explanation
    The nitrogenous bases of RNA are Adenine, Uracil, Guanine, and Cytosine. These bases are the building blocks of RNA molecules and are responsible for coding genetic information. Adenine pairs with Uracil, and Guanine pairs with Cytosine, forming the base pairs that make up the RNA molecule. Thymine is not present in RNA, it is only found in DNA.

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  • 32. 

    What are the nitrogenous bases of DNA?

    • A.

      Adenine

    • B.

      Uracil

    • C.

      Thymine

    • D.

      Guanine

    • E.

      Cytosine

    Correct Answer(s)
    A. Adenine
    C. Thymine
    D. Guanine
    E. Cytosine
    Explanation
    The nitrogenous bases of DNA are Adenine, Thymine, Guanine, and Cytosine. These bases are the building blocks of DNA and are responsible for carrying genetic information. Adenine pairs with Thymine, and Guanine pairs with Cytosine in the DNA double helix structure. This pairing is crucial for DNA replication and the transmission of genetic information during cell division. Uracil is a nitrogenous base found in RNA, not DNA.

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  • 33. 

    What is the pentose sugar used in DNA?

    Correct Answer(s)
    deoxyribose
    Explanation
    Deoxyribose is the pentose sugar used in DNA. It is a five-carbon sugar molecule that forms the backbone of DNA, connecting the nucleotide bases together. The "deoxy" prefix indicates that one oxygen atom is missing in deoxyribose compared to ribose, the pentose sugar found in RNA. This missing oxygen atom is important for the stability and structure of DNA, allowing it to form the double helix shape. Therefore, deoxyribose is essential for the formation and function of DNA.

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  • 34. 

    What is the pentose sugar used in RNA?

    Correct Answer(s)
    ribose
    Explanation
    Ribose is the correct answer because it is a pentose sugar that is used in the structure of RNA. RNA, or ribonucleic acid, is a nucleic acid that plays a crucial role in protein synthesis and gene expression. Ribose is a key component of RNA molecules, forming the backbone of the RNA strand. It is a five-carbon sugar that provides the necessary structure and stability for RNA molecules to carry out their functions in the cell.

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  • 35. 

    Where is DNA located?

    • A.

      All over the cell

    • B.

      Mostly in the nucleus

    Correct Answer
    B. Mostly in the nucleus
    Explanation
    DNA is primarily located in the nucleus of a cell. This is because the nucleus is the control center of the cell and contains the genetic material, which is DNA. While DNA can also be found in other parts of the cell, such as the mitochondria, the majority of it is concentrated in the nucleus where it is protected and organized.

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  • 36. 

    Where is RNA located?

    • A.

      Mostly in the nucleus

    • B.

      All over the cell

    Correct Answer
    B. All over the cell
    Explanation
    RNA is located all over the cell because it is involved in various cellular processes, not just limited to the nucleus. RNA molecules are synthesized in the nucleus through transcription and then transported to different parts of the cell where they perform their functions. This includes translating genetic information into proteins in the cytoplasm, as well as carrying out regulatory functions in organelles such as mitochondria. Therefore, RNA is not confined to a specific location but rather distributed throughout the cell.

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  • 37. 

    The backbone of DNA are made up of ______ and _______.

    Correct Answer
    pentose phosphate
    5 carbon sugar phosphate
    Explanation
    The backbone of DNA is made up of pentose phosphate and 5 carbon sugar phosphate. Pentose phosphate refers to the type of sugar molecule that forms the backbone, while 5 carbon sugar phosphate refers to the specific structure of the sugar molecule, which consists of a five-carbon ring with a phosphate group attached. These components alternate along the DNA molecule, forming a stable and structured backbone that supports the genetic information encoded in the DNA sequence.

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  • 38. 

    Phosphate carries a ______ charge.

    Correct Answer
    negative
    Explanation
    Phosphate carries a negative charge because it is an anion, meaning it has gained electrons and has more negative charges than positive charges. Phosphate consists of three oxygen atoms bonded to a central phosphorus atom, and the oxygen atoms are more electronegative than phosphorus, causing the molecule to have an overall negative charge. This negative charge allows phosphate to easily participate in chemical reactions and form bonds with other molecules.

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  • 39. 

    DNA carries a ____ charge.

    Correct Answer
    negative
    Explanation
    DNA carries a negative charge because it is composed of phosphate groups, which are negatively charged. Additionally, DNA contains sugar molecules that also contribute to its negative charge. This negative charge allows DNA to interact with positively charged molecules, such as proteins, in various cellular processes.

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  • 40. 

    One DNA strand is complementary to the other, choose the correct ones below.(multiple answers)

    • A.

      A + C

    • B.

      T + G

    • C.

      A + T

    • D.

      G + C

    Correct Answer(s)
    C. A + T
    D. G + C
    Explanation
    The correct answer is A + T and G + C. In DNA, the bases always pair up in a specific way: adenine (A) with thymine (T), and guanine (G) with cytosine (C). This is known as complementary base pairing. Therefore, the first answer (A + T) is correct because A is always paired with T, and the third answer (G + C) is also correct because G is always paired with C.

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  • 41. 

    DNA codes for RNA and RNA codes for a polypeptide chain.This shows what?

    • A.

      The flow of information from RNA.

    • B.

      The flow of information from DNA.

    • C.

      The flow of information from a polypeptide chain.

    Correct Answer
    B. The flow of information from DNA.
    Explanation
    The given answer is correct because it states that the flow of information is from DNA. This is supported by the fact that DNA codes for RNA, which in turn codes for a polypeptide chain. This process is known as the central dogma of molecular biology, where genetic information flows from DNA to RNA to protein. Therefore, the correct answer is the flow of information from DNA.

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  • 42. 

    ________ is to polysaccharide as amino acid is to __________.

    Correct Answer
    monosaccharide polypeptide chain
    Explanation
    Polysaccharides are complex carbohydrates made up of monosaccharide units bonded together. Similarly, amino acids are the building blocks of proteins, which are made up of polypeptide chains. Therefore, the analogy between polysaccharide and monosaccharide is the same as the analogy between amino acid and polypeptide chain.

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  • 43. 

    In classifying the molecules of life, what do fats and human sex hormones have in common?(multiple answers)

    • A.

      Soluble in water

    • B.

      Insoluble in water

    • C.

      Both are oils

    • D.

      Both are fats

    Correct Answer(s)
    B. Insoluble in water
    D. Both are fats
    Explanation
    Fats and human sex hormones have in common that they are insoluble in water and both are considered fats. This means that they do not mix or dissolve in water, but rather form separate layers or droplets. Fats and human sex hormones share this characteristic due to their chemical structure, which includes long hydrocarbon chains that are nonpolar and repel water molecules.

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  • 44. 

    What are the bonds that hold the nitrogenous bases together in the double helix?

    Correct Answer(s)
    hydrogen bonds
    Explanation
    Hydrogen bonds are the bonds that hold the nitrogenous bases together in the double helix of DNA. These bonds form between the nitrogenous bases of the two DNA strands, specifically between adenine and thymine, and between guanine and cytosine. Hydrogen bonds are relatively weak compared to covalent bonds, but they are essential for stabilizing the DNA structure and allowing for the separation of the two strands during DNA replication and transcription.

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  • 45. 

    Catalase is an _______.

    Correct Answer(s)
    enzyme
    Explanation
    Catalase is an enzyme that is responsible for the breakdown of hydrogen peroxide into water and oxygen. Enzymes are biological molecules that act as catalysts, speeding up chemical reactions in living organisms. They are typically proteins that have a specific shape and function. In the case of catalase, it helps to protect cells from the toxic effects of hydrogen peroxide by converting it into harmless substances. Therefore, the correct answer is enzyme.

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  • 46. 

    Catalase causes the break down of hydrogen peroxide to water and _______.

    Correct Answer(s)
    oxygen
    Explanation
    Catalase is an enzyme that facilitates the decomposition of hydrogen peroxide into water and oxygen. This reaction occurs because catalase speeds up the rate at which hydrogen peroxide molecules are broken down, resulting in the release of oxygen gas as a byproduct. Therefore, the correct answer is oxygen.

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  • 47. 

    Simple and facilitated diffusion involves the movement of molecules ________ their concentration gradient.

    • A.

      Along or down

    • B.

      Against

    Correct Answer
    A. Along or down
    Explanation
    Simple and facilitated diffusion involves the movement of molecules along or down their concentration gradient. This means that molecules move from an area of higher concentration to an area of lower concentration. In simple diffusion, molecules passively move across a membrane without the need for any additional proteins. Facilitated diffusion, on the other hand, requires the assistance of specific transport proteins to facilitate the movement of molecules across the membrane. In both cases, the movement occurs in the direction of lower concentration, which is either along or down the concentration gradient.

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  • 48. 

    Active transport uses _____ or _____.

    Correct Answer
    pumps vesicles
    Explanation
    Active transport is a process in which substances are moved across a cell membrane against their concentration gradient, requiring energy. This energy is provided by specialized proteins called pumps. These pumps actively transport molecules or ions across the membrane, either by pumping them directly or by using vesicles. Vesicles are small, membrane-bound sacs that transport substances within the cell. Therefore, active transport uses pumps or vesicles to move substances across the cell membrane.

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  • 49. 

    Active transport requires the use of _____  _______ in the form of _____.

    Correct Answer
    cellular energy, ATP
    Explanation
    Active transport is a process that requires energy to move molecules across a cell membrane against their concentration gradient. In this case, the question is asking for the specific type of energy and its form used in active transport. The correct answer is cellular energy, ATP. ATP (adenosine triphosphate) is the main energy currency of cells and is used to power various cellular processes, including active transport. By using ATP, cells are able to actively transport molecules across the membrane, allowing them to maintain concentration gradients and perform essential functions.

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  • 50. 

    A ______   ______ is the amount of stuff in any particular area.

    Correct Answer
    concentration gradient
    Explanation
    A concentration gradient refers to the difference in concentration of a substance across a given area. It indicates the amount of stuff (substance) present in different parts of that area. The concentration gradient can be used to measure the rate of diffusion or movement of substances from an area of higher concentration to an area of lower concentration.

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  • Mar 22, 2023
    Quiz Edited by
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  • Mar 08, 2010
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