Unit 1 Chapter 2 (1st Secondary) Biology

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  • 1/95 Questions

    A nucleotide of DNA may contain ________.

    • Ribose, uracil, and a phosphate group
    • Deoxyribose, uracil, and a phosphate group
    • Deoxyribose, thymine, and a phosphate group
    • Ribose, thymine, and a phosphate group
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About This Quiz

Explore the fundamentals of genetics in this Unit 1 Chapter 2 quiz for 1st secondary biology. Topics include DNA structure, nucleotide components, protein synthesis, and properties of fats. This quiz assesses understanding of basic genetic concepts and their biological applications.

Unit 1 Chapter 2 (1st Secondary) Biology - Quiz

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  • 2. 

    In the formation of a macromolecule, what type of bond would join two amino acid subunits?

    • Ionic bond

    • Bond between two carbon atoms

    • Hydrogen bond

    • Peptide bond

    Correct Answer
    A. Peptide bond
    Explanation
    A peptide bond would join two amino acid subunits in the formation of a macromolecule. A peptide bond is a covalent bond that forms between the carboxyl group of one amino acid and the amino group of another amino acid. This bond is formed through a dehydration synthesis reaction, where a water molecule is removed, allowing the amino acids to join together.

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  • 3. 

    Dehydration and hydrolysis reactions involve removing or adding ______ to macromolecule subunits.

    • C and O

    • C and H

    • COOH and H

    • OH and H

    Correct Answer
    A. OH and H
    Explanation
    Dehydration reactions involve removing OH (hydroxyl) from one molecule and H (hydrogen) from another molecule, resulting in the formation of a covalent bond between the two molecules. This process leads to the synthesis of a larger molecule and the release of water as a byproduct. On the other hand, hydrolysis reactions involve breaking down a larger molecule into smaller subunits by adding OH (hydroxyl) to one subunit and H (hydrogen) to another subunit, with water being consumed in the process. Therefore, OH and H are the components involved in both dehydration and hydrolysis reactions.

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  • 4. 

    Which element occurs in nucleic acids?

    • Manganese

    • Calcium

    • Phosphorus

    • Sulfur

    Correct Answer
    A. Phosphorus
    Explanation
    Nucleic acids, such as DNA and RNA, are composed of nucleotides, which consist of a sugar molecule, a phosphate group, and a nitrogenous base. Phosphorus is a crucial component of the phosphate group in nucleotides, making it an essential element in nucleic acids. Manganese, calcium, and sulfur do not play a significant role in the structure or function of nucleic acids.

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  • 5. 

    Each protein molecule is made up of …..

    • Carbohydrates

    • Fatty acids

    • Amino acids

    • Nucleotides

    Correct Answer
    A. Amino acids
    Explanation
    Protein molecules are composed of amino acids. Amino acids are the building blocks of proteins and are linked together through peptide bonds to form long chains. These chains then fold into specific three-dimensional structures, which determine the function of the protein. Carbohydrates, fatty acids, and nucleotides are not the primary components of proteins.

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  • 6. 

    There are about ……. amino acids in all which, can be linked together in different ways to make numerous protein molecules.

    • 40

    • 20

    • 25

    • 30

    Correct Answer
    A. 20
    Explanation
    There are about 20 amino acids in all which can be linked together in different ways to make numerous protein molecules.

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  • 7. 

    The DNA consists of two …….. coiled strands.

    • Spherically

    • Spirally

    • Angularly

    • Cubically

    Correct Answer
    A. Spirally
    Explanation
    DNA consists of two spirally coiled strands, known as a double helix. The spiral shape allows the DNA molecule to fit within the nucleus of a cell and also facilitates the replication and transcription processes. The strands are held together by hydrogen bonds between complementary base pairs, adenine with thymine and guanine with cytosine. This spiral structure is crucial for the stability and function of DNA in storing and transmitting genetic information.

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  • 8. 

    A nucleotide has ……….

    • Nitrogenous base + phosphoric acid + sugar

    • Two sugar molecules + phosphoric acid

    • Three phosphoric acid molecules

    • Two phosphoric acid + nitrogenous base

    Correct Answer
    A. Nitrogenous base + phosphoric acid + sugar
    Explanation
    A nucleotide is composed of three components: a nitrogenous base, a phosphoric acid, and a sugar molecule. These three components together make up the structure of a nucleotide.

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  • 9. 

    The diagram shows a molecule of an amino acid. What are the functional groups in this molecule?

    • A and C

    • A and B

    • B and C

    • A, B and C

    Correct Answer
    A. A and C
    Explanation
    The diagram shows a molecule of an amino acid, which consists of an amino group (-NH2) and a carboxyl group (-COOH). These are the functional groups in this molecule. Therefore, the correct answer is A and C, as option A represents the amino group and option C represents the carboxyl group.

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  • 10. 

    In the structure below of the amino acid. How many different group (B)s are there?

    • 22

    • 14

    • 20

    • 3

    Correct Answer
    A. 20
    Explanation
    In the structure of an amino acid, there are 20 different groups (B). This is because there are 20 different amino acids that make up proteins, each with a unique side chain or R group. These side chains can vary in size, shape, and chemical properties, which contribute to the diversity and functionality of proteins. Therefore, there are 20 different groups (B) in the structure of an amino acid.

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  • 11. 

    What happens to the colour of the Biuret reagent after being added to each of the three test tubes?

    • A changes to violet / B changes to violet / C no change.

    • A Changes to violet / B no change / C no change.

    • A no change / B changes to violet / C changes to violet.

    • A no change / B no change / C changes to violet.

    Correct Answer
    A. A Changes to violet / B no change / C no change.
  • 12. 

    Which of the following statements is correct?

    • Simple sugar is composed of starch molecules.

    • Protein is composed of amino acids.

    • Glycerol is composed of fatty acids.

    • Nucleotides are composed of nucleic acids.

    Correct Answer
    A. Protein is composed of amino acids.
    Explanation
    Proteins are large, complex molecules that are composed of amino acids. Amino acids are the building blocks of proteins, and they are linked together through peptide bonds to form long chains. This statement is correct because it accurately describes the composition of proteins.

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  • 13. 

    Proteins differ from one another in ……

    • Number of amino acids.

    • Type of amino acids.

    • Order of amino acids.

    • All of the above.

    Correct Answer
    A. All of the above.
    Explanation
    Proteins differ from one another in all of the mentioned ways. The number of amino acids in a protein determines its length and size. The type of amino acids present in a protein determines its chemical properties and functions. The order of amino acids in a protein determines its unique sequence and structure, which ultimately determines its specific function in the body. Therefore, all of these factors contribute to the differences observed among proteins.

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  • 14. 

    From the phosphoproteins we have ……….

    • Casein

    • Thyroxine

    • Insuline

    • Haemoglobin

    Correct Answer
    A. Casein
    Explanation
    Casein is a phosphoprotein found in milk. It is the main protein in milk and is responsible for the white color of milk. It is a rich source of essential amino acids and is commonly used in the production of cheese and other dairy products. Thyroxine, insulin, and hemoglobin are not phosphoproteins. Thyroxine is a hormone produced by the thyroid gland, insulin is a hormone produced by the pancreas, and hemoglobin is a protein found in red blood cells that carries oxygen.

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  • 15. 

    When trypsin enzyme is present in a sample, the biuret will turn _____.

    • Blue

    • Green

    • Violet

    • Orange

    Correct Answer
    A. Violet
    Explanation
    Trypsin is a proteolytic enzyme that breaks down proteins into smaller peptides. Biuret reagent is commonly used to test for the presence of proteins. When trypsin enzyme is present in a sample, it will break down the proteins into smaller peptides. Biuret reagent reacts with the peptide bonds in proteins, causing a color change. In the presence of trypsin enzyme, the biuret reagent will turn violet, indicating the presence of proteins that have been broken down by trypsin.

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  • 16. 

    One of the following statements describing the similarities between ribose and deoxyribose, is not correct …..

    • Both are pentoses

    • Both enter in the structure of nucleotides

    • Both are monosaccharide

    • Both have an OH group attached to C2’

    Correct Answer
    A. Both have an OH group attached to C2’
    Explanation
    Both ribose and deoxyribose are pentoses, meaning they have five carbon atoms. They both enter into the structure of nucleotides, which are the building blocks of DNA and RNA. Additionally, they are both monosaccharides, which means they cannot be hydrolyzed to form simpler sugars. However, the statement that both ribose and deoxyribose have an OH group attached to C2' is incorrect. Ribose has an OH group attached to C2', while deoxyribose lacks this group, hence the name "deoxy" indicating the absence of an oxygen atom.

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  • 17. 

    Table salt is iodized in large part to prevent the enlargement of the ..... gland(s).

    • Adrenal

    • Pituitary

    • Salivary

    • Thyroid

    Correct Answer
    A. Thyroid
    Explanation
    Table salt is iodized in large part to prevent the enlargement of the thyroid gland. The thyroid gland requires iodine to produce thyroid hormones, which are essential for regulating metabolism and growth. Without enough iodine, the thyroid gland can become enlarged, leading to a condition called goiter. By adding iodine to table salt, it ensures that individuals receive enough iodine in their diet to prevent goiter and maintain proper thyroid function.

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  • 18. 

    Why does the hydrolysis of histones produce amino acids only?

    • Because DNA molecules are coiled around different histone subunits

    • Because histones are simple proteins

    • Because histones are soluble in water

    • Because histones are basic proteins

    Correct Answer
    A. Because histones are simple proteins
    Explanation
    The hydrolysis of histones produces amino acids only because histones are simple proteins. Hydrolysis is a chemical reaction that breaks down molecules by adding water. In the case of histones, the hydrolysis reaction breaks the peptide bonds between amino acids, resulting in the release of individual amino acids. Since histones are made up of amino acids linked together, the hydrolysis of histones would naturally produce amino acids as the end product.

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  • 19. 

    Small molecules are used as the basic units in the synthesis of large food molecules. Which of the following statements is correct?

    • Amino acids are basic units of carbohydrates

    • Fatty acids are basic units of glycogen

    • Glycerol is a basic unit of oils

    • Simple sugar is a basic unit of protein

    Correct Answer
    A. Glycerol is a basic unit of oils
    Explanation
    Glycerol is a basic unit of oils because oils are triglycerides, which are composed of three fatty acids attached to a glycerol molecule. The glycerol molecule acts as a backbone for the attachment of the fatty acids, forming the structure of oils.

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  • 20. 

    If you know that Elodea is it a fully submerged plant, which of the following compounds protect the cell wall from being dissolved in water?

    • Simple sugars

    • Conjugated proteins

    • Derived lipids

    • Complex sugars

    Correct Answer
    A. Complex sugars
    Explanation
    Complex sugars protect the cell wall from being dissolved in water. Elodea is a fully submerged plant, and the cell wall of plants is composed of complex sugars called cellulose. Cellulose provides structural support and prevents the cell wall from breaking down in water. Simple sugars, derived lipids, and conjugated proteins do not have the same protective effect on the cell wall.

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  • 21. 

    The following are two diagrams of reactions between amino acids. Which diagram shows a condensation polymerization reaction?

    • X

    • Y

    • Both of them

    • Neither of them

    Correct Answer
    A. Y
    Explanation
    Diagram Y shows a condensation polymerization reaction because it depicts the formation of a larger molecule by the removal of a small molecule, such as water, during the reaction. This process is characteristic of condensation polymerization, where monomers join together to form a polymer while releasing a small molecule as a byproduct. In contrast, diagram X does not show the removal of a small molecule and therefore does not represent a condensation polymerization reaction.

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  • 22. 

    Which of the following is not the function of proteins?

    • Helps in digesting food

    • Carries genetic information

    • Fights against the invading pathogens

    • Helps in transporting oxygen in the blood

    Correct Answer
    A. Carries genetic information
    Explanation
    Proteins are macromolecules that perform a wide range of functions in the body. They are involved in digestion, as enzymes help break down food. They also play a role in the immune system, as antibodies help fight against pathogens. Additionally, proteins are responsible for transporting oxygen in the blood, as hemoglobin binds to oxygen molecules. However, proteins do not carry genetic information. Genetic information is carried by DNA, which is a nucleic acid.

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  • 23. 

    Ferritin is a protein that stores iron in the body and releases it in a controlled manner. A molecule of ferritin is composed of protein and iron. Which of the following types of proteins is ferritin?

    • Simple protein

    • Fibrous protein

    • Conjugated protein

    • Structural protein

    Correct Answer
    A. Conjugated protein
    Explanation
    Ferritin is classified as a conjugated protein because it consists of both protein and iron. Conjugated proteins are composed of a protein component and a non-protein component, such as a metal ion or a carbohydrate. In the case of ferritin, the protein component forms a shell-like structure that encloses and stores iron ions. This allows ferritin to regulate the release of iron in a controlled manner, making it an important protein for iron storage in the body.

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  • 24. 

    Protein molecules are mostly made up of ………

    • Carbon, hydrogen, oxygen and nitrogen

    • Carbon, hydrogen, carbon monoxide and nitrogen

    • Carbon, hydrogen, oxygen and methane

    • Carbon, hydrogen, oxygen and sulpher

    Correct Answer
    A. Carbon, hydrogen, oxygen and nitrogen
    Explanation
    Protein molecules are composed of long chains of amino acids. These amino acids are made up of carbon, hydrogen, oxygen, and nitrogen atoms. Carbon provides the backbone for the structure of the amino acids, while hydrogen and oxygen are also essential for the formation of various functional groups within the amino acids. Nitrogen is crucial for the formation of peptide bonds between amino acids, which are responsible for linking the amino acids together to form the protein molecule. Therefore, the correct answer is carbon, hydrogen, oxygen, and nitrogen.

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  • 25. 

    Which of the following can be used as intermediate-term energy storage?

    • Glycogen

    • Amino acids

    • Nucleic acids

    • Lipids

    Correct Answer
    A. Glycogen
    Explanation
    Glycogen can be used as intermediate-term energy storage because it is a polysaccharide that is synthesized and stored in the liver and muscles. When energy is needed, glycogen can be broken down into glucose, which can then be used for energy production. This process allows for a relatively quick release of energy when needed, making glycogen an ideal choice for intermediate-term energy storage.

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  • 26. 

    Identify each of the following test tubes, A, B, C and D ......

    • A iodine on starch / B benedict on glucose / C biuret on albumen / D sudan IV on palm oil.

    • A biuret on albumen / B benedict on glucose / C iodine on starch / D sudan IV on palm oil.

    • A iodine on starch / B biuret on albumen / C sudan IV on palm oil / D benedict on glucose

    • A biuret on albumen / B benedict on glucose / C sudan IV on palm oil / D iodine on starch.

    Correct Answer
    A. A biuret on albumen / B benedict on glucose / C iodine on starch / D sudan IV on palm oil.
    Explanation
    Test tube A is identified as biuret on albumen because biuret test is used to detect the presence of proteins, and albumen is a protein. Test tube B is identified as benedict on glucose because benedict test is used to detect the presence of reducing sugars, and glucose is a reducing sugar. Test tube C is identified as iodine on starch because iodine test is used to detect the presence of starch, and starch gives a blue-black color with iodine. Test tube D is identified as sudan IV on palm oil because sudan IV test is used to detect the presence of lipids, and palm oil is a lipid.

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  • 27. 

    How many different tripeptides can be formed from the three different amino acids, methionine, histidine, and arginine? (Don't allow any amino acid to be repeated)

    • 3

    • 5

    • 6

    • 9

    Correct Answer
    A. 6
    Explanation
    There are three different amino acids, and we need to form tripeptides without repeating any amino acid. This means we can choose any of the three amino acids for the first position, then we have two options left for the second position, and finally only one option for the third position. So, the total number of different tripeptides that can be formed is 3 * 2 * 1 = 6.

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  • 28. 

    The following molecule is a(an) .......

    • Amino acid

    • Carbohydrate

    • Nucleic acid

    • Lipid

    Correct Answer
    A. Carbohydrate
    Explanation
    The given molecule is most likely a carbohydrate because it is composed of carbon, hydrogen, and oxygen atoms in a ratio of 1:2:1. Carbohydrates are organic compounds that serve as a major source of energy for living organisms and are commonly found in foods such as sugars, starches, and fibers.

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  • 29. 

    Assuming they all had the same number of carbon atoms, which of the following has the most C-H bonds?

    • Unsaturated fat

    • Dipeptide

    • Disaccharide

    • Saturated fat

    Correct Answer
    A. Saturated fat
    Explanation
    Saturated fats have the most C-H bonds because they are composed of long chains of carbon atoms bonded to hydrogen atoms. Unlike unsaturated fats, which have double bonds between some carbon atoms, saturated fats have single bonds between all carbon atoms, allowing for more C-H bonds. Dipeptides and disaccharides do not contain carbon-hydrogen bonds in their structures.

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  • 30. 

    What type of macromolecule carries out catalysis in biological systems?

    • Proteins called enzymes

    • Carbohydrates called starches

    • Lipids called steroids

    • Nucleic acids called DNA

    Correct Answer
    A. Proteins called enzymes
    Explanation
    Proteins called enzymes carry out catalysis in biological systems. Enzymes are specialized proteins that act as catalysts, speeding up chemical reactions in living organisms. They bind to specific substrates and facilitate the conversion of these substrates into products. Enzymes are essential for various biological processes such as metabolism, digestion, and DNA replication. They are highly specific and can be regulated to control the rate of reactions in cells. Other macromolecules like carbohydrates, lipids, and nucleic acids do not possess the same catalytic properties as enzymes.

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  • 31. 

    Nucleotides have a nitrogenous base attached to a sugar at the …...

    • 1' carbon

    • 2' carbon

    • 3' carbon

    • 5' carbon

    Correct Answer
    A. 1' carbon
    Explanation
    Nucleotides are the building blocks of DNA and RNA. They consist of a nitrogenous base attached to a sugar molecule. The sugar molecule in DNA is deoxyribose, while in RNA it is ribose. The carbon atoms in the sugar molecule are numbered from 1' to 5'. In a nucleotide, the nitrogenous base is attached to the 1' carbon of the sugar molecule through a glycosidic bond. Therefore, the correct answer is 1' carbon.

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  • 32. 

    Which part of the amino acid gives it uniqueness?

    • Amino group

    • Carboxyl group

    • Alkyl group

    • Peptide bond

    Correct Answer
    A. Alkyl group
    Explanation
    The alkyl group is what gives an amino acid its uniqueness. Amino acids are made up of a central carbon atom that is bonded to four different groups: an amino group, a carboxyl group, a hydrogen atom, and an alkyl group. It is the specific arrangement and composition of the alkyl group that differentiates one amino acid from another. The alkyl group can vary in size and structure, which leads to the diversity of amino acids and their different properties and functions in biological systems.

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  • 33. 

    The DNA …….

    • Store information for controlling all cellular activities.

    • Synthesizes fats.

    • Produces energy.

    • All of the above.

    Correct Answer
    A. Store information for controlling all cellular activities.
    Explanation
    The correct answer is "Store information for controlling all cellular activities." DNA is the genetic material that carries the instructions for the development, functioning, and reproduction of all living organisms. It contains the information needed to control all cellular activities, including the synthesis of proteins, regulation of gene expression, and transmission of hereditary traits. DNA is responsible for the storage and transmission of genetic information from one generation to the next.

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  • 34. 

    In a DNA molecule, adenine binds with thymine by a …..

    • Single bond

    • Double bond

    • Triple bond

    • Ionic bond

    Correct Answer
    A. Double bond
    Explanation
    In a DNA molecule, adenine binds with thymine by a double bond. This is because adenine and thymine are complementary base pairs, and they form two hydrogen bonds between them. The double bond between adenine and thymine is important for the stability and integrity of the DNA molecule.

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  • 35. 

    In a DNA molecule, cytosine binds with guanine by a ……

    • Single bond

    • Double bond

    • Triple bond

    • Ionic bond

    Correct Answer
    A. Triple bond
    Explanation
    Cytosine binds with guanine in a DNA molecule through a triple bond. This triple bond is formed between the nitrogenous bases of cytosine and guanine. The triple bond provides a strong and stable connection between the two bases, contributing to the stability and structure of the DNA molecule.

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  • 36. 

    Which of the following can be used as short-term energy storage?

    • Carbohydrates

    • Triglycerides

    • ATP 

    • Proteins

    Correct Answer
    A. ATP 
    Explanation
    ATP (adenosine triphosphate) can be used as short-term energy storage. ATP is a molecule that stores and releases energy in cells. It is commonly referred to as the "energy currency" of the cell because it provides the energy necessary for cellular processes. When ATP is broken down into ADP (adenosine diphosphate) and inorganic phosphate, energy is released, which can be used for various cellular activities. Carbohydrates, triglycerides, and proteins are also sources of energy, but ATP is specifically designed for short-term energy storage and transfer within cells.

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  • 37. 

    Which of the following statements is true for compounds like glycoprotein and glycolipids?

    • They are conjugated molecules of carbohydrates.

    • Both are made out of carbohydrate attached to amino acid molecules.

    • Both enter in the structure of the cell wall.

    • Both are made out of carbohydrates attached to fatty acid molecules.

    Correct Answer
    A. They are conjugated molecules of carbohydrates.
    Explanation
    Glycoproteins and glycolipids are both examples of conjugated molecules of carbohydrates. This means that they consist of a carbohydrate component attached to a protein or lipid molecule, respectively. These compounds play important roles in various biological processes, such as cell signaling and recognition.

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  • 38. 

    Peptide bond is ......

    • C - O link

    • N - H link

    • C - H link

    • C - N link

    Correct Answer
    A. C - N link
    Explanation
    A peptide bond is a covalent bond formed between the carboxyl group (C) of one amino acid and the amino group (N) of another amino acid. This bond is formed through a condensation reaction, where a water molecule is eliminated. Therefore, the correct answer is C - N link.

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  • 39. 

    How many turns does a molecule of DNA consists of 2000 base pairs have?

    • 20

    • 200

    • 100

    • 400

    Correct Answer
    A. 200
    Explanation
    A molecule of DNA consists of two strands that are twisted around each other in a double helix structure. Each base pair consists of two nucleotides that are bonded together. The number of turns in a DNA molecule is determined by the number of base pairs it has. In this case, the molecule of DNA consists of 2000 base pairs, so it would have 200 turns.

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  • 40. 

    DNA is composed of repeating units of ………

    • Ribonucleosides

    • Ribonucleotides

    • Deoxyribonucleosides

    • Deoxyribonucleotides.

    Correct Answer
    A. Deoxyribonucleotides.
    Explanation
    DNA is composed of repeating units called nucleotides. These nucleotides consist of a sugar molecule (deoxyribose), a phosphate group, and a nitrogenous base. Therefore, the correct answer is deoxyribonucleotides, as they contain the deoxyribose sugar that is characteristic of DNA. Ribonucleosides and ribonucleotides contain a different sugar molecule (ribose) and are found in RNA, not DNA.

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  • 41. 

    Albumin is found in …..

    • Plant’s roots

    • Plant’s leaves

    • Plasma of Blood

    • Saliva

    Correct Answer
    A. Plasma of Blood
    Explanation
    Albumin is a protein that is primarily found in the plasma of blood. It is the most abundant protein in the blood and plays a crucial role in maintaining the osmotic pressure and transporting various substances such as hormones, fatty acids, and drugs. Albumin also helps in the regulation of blood volume and pH balance. While plants do have proteins, albumin is not typically found in plant tissues such as roots or leaves. Similarly, while saliva also contains proteins, albumin is not a major component of saliva. Therefore, the correct answer is plasma of blood.

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  • 42. 

    Tri-peptide consists of .....

    • 3 amino acids and 2 peptide bonds

    • 3 amino acids and 3 peptide bonds

    • 2 amino acids and 3 peptide bonds

    • 3 amino acids and 4 peptide bonds

    Correct Answer
    A. 3 amino acids and 2 peptide bonds
    Explanation
    A tri-peptide consists of three amino acids joined together by two peptide bonds. Peptide bonds are formed when the carboxyl group of one amino acid reacts with the amino group of another amino acid, resulting in the formation of a peptide bond and the release of a water molecule. Therefore, a tri-peptide would have two peptide bonds connecting the three amino acids.

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  • 43. 

    What is the complementary DNA strand that is created from this template during replication? 3’ T A C C G A T T G C A 5’

    • 5’ATGGCTAACGT 3’

    • 5’TGCAATGCCTA 3’

    • 5’AUGGCUAACGU 3’

    • 5’TAGGCATTGCA 3’

    Correct Answer
    A. 5’ATGGCTAACGT 3’
    Explanation
    The complementary DNA strand is created by pairing each nucleotide with its complementary base. In this case, the template strand has the sequence 3’ T A C C G A T T G C A 5’. The complementary strand will have the same sequence but with the complementary bases. A pairs with T, T pairs with A, C pairs with G, and G pairs with C. Therefore, the complementary DNA strand is 5’ATGGCTAACGT 3’.

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  • 44. 

    Which association between complementary bases would require the most energy to break?

    • A:U

    • A:T

    • G:C

    • All require the same energy

    Correct Answer
    A. G:C
    Explanation
    The G:C association would require the most energy to break because it is a stronger bond compared to the other options. G:C forms three hydrogen bonds, while A:T and A:U only form two hydrogen bonds. The additional hydrogen bond in G:C makes it more stable and harder to break, thus requiring more energy.

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  • 45. 

    A molecule of DNA consists of 300 base pair. If the number of thymine base is 150. What is the number of the triple hydrogen bonds found in the molecule?

    • 150

    • 300

    • 600

    • 100

    Correct Answer
    A. 150
    Explanation
    The number of triple hydrogen bonds found in a molecule of DNA is equal to the number of adenine-thymine pairs. Since the number of thymine bases is given as 150, it means there are 150 adenine bases as well. Each adenine-thymine pair forms two hydrogen bonds, so the total number of triple hydrogen bonds is 150 (adenine-thymine pairs) multiplied by 2 (hydrogen bonds per pair), which equals 300. Therefore, the correct answer is 300.

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  • 46. 

    A molecule of DNA consists of 200 base pair. What is the number of the free phosphate groups found in the molecule?

    • 200

    • 400

    • 10

    • 2

    Correct Answer
    A. 2
    Explanation
    A molecule of DNA consists of two strands, each made up of a chain of nucleotides. Each nucleotide in DNA consists of a phosphate group, a sugar molecule, and a nitrogenous base. In a DNA molecule, there are two phosphate groups, one on each end of the double helix structure. Therefore, the number of free phosphate groups found in the molecule is 2.

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  • 47. 

    Which of the following structures can be formed when amino acids combine into specialized proteins in your body?

    • Enzymes, hormones, and ligaments

    • Hormones, DNA, and RNA

    • Tendons, glycogen, and DNA

    • Enzymes, RNA, and cholesterol

    Correct Answer
    A. Enzymes, hormones, and ligaments
    Explanation
    Amino acids combine to form specialized proteins in the body. Enzymes are proteins that act as catalysts in biochemical reactions. Hormones are chemical messengers that regulate various bodily functions. Ligaments are tough connective tissues that connect bones to each other and provide stability to joints. Therefore, enzymes, hormones, and ligaments are all structures that can be formed when amino acids combine into specialized proteins in the body.

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  • 48. 

    Which of the following best represents the backbone arrangement of peptide bonds? The alpha carbon (α-carbon or Cα) is what connects the amino group to the acid carboxyl group.

    • Cα—N—C—Cα—N—C

    • Cα—N—C—C—N—Cα

    • C—N—Cα—Cα—C—N

    • Cα—C—N—Cα—C—N

    Correct Answer
    A. Cα—C—N—Cα—C—N
    Explanation
    The correct answer represents the backbone arrangement of peptide bonds as Cα-C-N-Cα-C-N. This arrangement shows the connection between the alpha carbon (Cα) and the nitrogen (N) atoms in the peptide bond, with the carbon (C) atoms in between. This arrangement is characteristic of the peptide backbone structure, where the amino group (NH2) and the carboxyl group (COOH) are attached to the alpha carbon.

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  • 49. 

    To form a chain from three similar amino acids linked together in several times with various arrangements. What is the maximum number of different polypeptide chains that can be formed?

    • One chain

    • Two chains

    • Three chains

    • Six chains

    Correct Answer
    A. One chain
    Explanation
    The question asks for the maximum number of different polypeptide chains that can be formed from three similar amino acids. Since the amino acids are similar, there is only one possible arrangement of the three amino acids to form a chain. Therefore, the maximum number of different polypeptide chains that can be formed is one.

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Quiz Review Timeline (Updated): Mar 9, 2023 +

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  • Current Version
  • Mar 09, 2023
    Quiz Edited by
    ProProfs Editorial Team
  • Jul 31, 2020
    Quiz Created by
    Samy

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