Biology: Nucleic Acids and Enzymes
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Questions and Answers

What is one way enzymes lower activation energy?

  • By increasing substrate concentration
  • By interfering with enzyme function
  • By activating the substrate directly
  • By altering bond structures in the substrate (correct)

    • Enzymes function optimally in any environment without restrictions.

    False

    Name one factor that can alter the rate of enzyme reactions.

    Temperature, pH, or enzyme concentration

    Enzymes can facilitate the __________ of electrons to or from a substrate.

    <p>transfer</p> Signup and view all the answers

    Match the following factors to their effect on enzyme activity:

    <p>Temperature = Can denature enzymes if too high pH = Affects the ionization of the substrate Enzyme concentration = Increases reaction rate up to a point Substrate concentration = Can also increase reaction rate until saturation</p> Signup and view all the answers

    What are the primary functions of nucleic acids?

    <p>Hereditary material and protein synthesis</p> Signup and view all the answers

    DNA consists of a single strand.

    <p>False</p> Signup and view all the answers

    What type of bond connects the base pairs in DNA?

    <p>Hydrogen bonds</p> Signup and view all the answers

    RNA is typically ________________.

    <p>single stranded</p> Signup and view all the answers

    Match the following components of nucleotides with their descriptions:

    <p>Nitrogenous Base = A component that varies among nucleotides and provides genetic information Phosphate Group = A functional group that links nucleotides together Sugar Ring = A five-carbon sugar that forms part of the nucleotide structure Antiparallel Strands = Describes the orientation of the two strands in a DNA molecule</p> Signup and view all the answers

    Which of the following pairs are considered complementary base pairs in DNA?

    <p>A - T</p> Signup and view all the answers

    Deoxyribonucleic acid contains ribose sugar.

    <p>False</p> Signup and view all the answers

    Nucleotides are joined by ____________ bonds.

    <p>phosphodiester</p> Signup and view all the answers

    Which of the following is a difference between RNA and DNA?

    <p>RNA contains uracil while DNA contains thymine</p> Signup and view all the answers

    DNA and RNA are made of different types of nucleotides.

    <p>False</p> Signup and view all the answers

    What are the complementary base pairs for the DNA sequence 5’CCGCAAACCCGCTATGTT3’?

    <p>3’GGCGTTTGGGCATACA5’</p> Signup and view all the answers

    The __________ fits precisely in the __________ in order for the reaction to proceed.

    <p>substrate, active site</p> Signup and view all the answers

    Match the following nucleobases to their corresponding pairs in DNA:

    <p>Adenine = Thymine Cytosine = Guanine Guanine = Cytosine Thymine = Adenine</p> Signup and view all the answers

    What does the 3’ and 5’ indicate in a DNA strand?

    <p>The direction of strand growth</p> Signup and view all the answers

    Enzymes are consumed during the reactions they catalyze.

    <p>False</p> Signup and view all the answers

    What is the induced-fit model in relation to enzymes?

    <p>The induced-fit model describes how the substrate interacts with the enzyme's active site, allowing for a precise fit and catalysis.</p> Signup and view all the answers

    What occurs when an activator binds to an enzyme?

    <p>It stabilizes the enzyme in its active form.</p> Signup and view all the answers

    Non-competitive inhibitors bind to the active site of the enzyme.

    <p>False</p> Signup and view all the answers

    What is the role of the end product in feedback inhibition?

    <p>It acts as an inhibitor.</p> Signup and view all the answers

    An enzyme's active site changes shape when a __________ binds to it.

    <p>non-competitive inhibitor</p> Signup and view all the answers

    Match the following terms with their definitions:

    <p>Allosteric Inhibitor = Stabilizes the enzyme in its active form Activator = Changes the shape of the active site Feedback Inhibition = Inhibits an earlier enzymatic reaction Substrate = The molecule upon which an enzyme acts</p> Signup and view all the answers

    At what temperature is enzyme activity at its peak?

    <p>Body temperature</p> Signup and view all the answers

    Enzymes are most active at a pH of 2 in the stomach.

    <p>True</p> Signup and view all the answers

    What happens to enzyme activity at very high temperatures?

    <p>Proteins denature.</p> Signup and view all the answers

    Adding more substrate will eventually cause activity to _____ as the enzyme becomes limiting.

    <p>taper off</p> Signup and view all the answers

    Which of the following factors can activate enzymes?

    <p>Cofactors/Coenzymes</p> Signup and view all the answers

    Name one type of inhibitor that can regulate enzyme activity.

    <p>Competitive inhibitor</p> Signup and view all the answers

    Match the following factors with their effect on enzyme activity:

    <p>Low Temperature = Limited activity Body Temperature = Peak activity Very High Temperature = Zero activity due to denaturation Low pH = Enzymes active in the stomach</p> Signup and view all the answers

    What is the initial effect of increasing enzyme concentration on rate of reaction?

    <p>Rate will peak and then plateau</p> Signup and view all the answers

    Study Notes

    Nucleic Acids

    • Nucleic acids are polymers made of nucleotide monomers.
    • They primarily function as hereditary material (DNA) and play roles in protein synthesis (RNA).
    • Nucleotides are composed of a sugar molecule (ribose for RNA, deoxyribose for DNA), a phosphate group, and a nitrogenous base.
    • Nitrogenous bases are categorized as purines (Adenine and Guanine) or pyrimidines (Cytosine, Thymine in DNA, and Uracil in RNA).
    • DNA is a double helix with two antiparallel strands, held together by hydrogen bonds between complementary base pairs: Adenine pairs with Thymine, and Cytosine pairs with Guanine.
    • RNA is typically single-stranded.

    Enzymes

    • Enzymes are proteins that catalyze (speed up) biological reactions.
    • Most enzymes are named after the reaction they catalyze and end in "-ase."
    • Enzymes have a specific active site that fits precisely with the substrate, enabling the reaction to proceed.
    • The induced-fit model describes how the substrate interacts with the enzyme's active site, leading to a conformational change that weakens bonds in the substrate and accelerates the reaction.
    • Enzymes lower activation energy by providing an alternative reaction pathway, facilitating the transfer of electrons or H+ ions to or from the substrate.
    • Enzyme activity is influenced by environmental factors such as temperature, pH, enzyme concentration, and substrate concentration.
    • Enzyme activity can be regulated by:
      • Cofactors/Coenzymes: Activators that bind to the enzyme, inducing a conformational change and increasing activity.
      • Competitive Inhibitors: Molecules that resemble the substrate and bind to the active site, preventing the substrate from binding.
      • Non-Competitive Inhibitors: Molecules that bind to a site other than the active site, altering the enzyme's shape and disabling its activity.
      • Allosteric Changes: Conformational changes induced by activator or inhibitor molecules, affecting the enzyme's activity.
      • Feedback Inhibition: A mechanism where the final product of a metabolic pathway acts as an inhibitor to an early enzyme in the pathway, regulating the pathway's activity.

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    1.5 Nucleic Acids & 1.6 Enzymes_Completed PDF

    Description

    This quiz covers essential concepts in molecular biology, focusing on nucleic acids like DNA and RNA, alongside the role of enzymes in biological reactions. Test your understanding of nucleotide structures, base pairing, and enzyme functionalities. A great way to solidify your knowledge in these fundamental topics!

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