Unit 1 Chapter 2 (1st Secondary) Biology
. Proteins and Nucleic acids
- 1.
Which part of the amino acid gives it uniqueness?
- A.
Amino group
- B.
Carboxyl group
- C.
Alkyl group
- D.
Peptide bond
Correct Answer
C. Alkyl groupExplanation
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.Rate this question:
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- 2.
Proteins differ from one another in ……
- A.
Number of amino acids.
- B.
Type of amino acids.
- C.
Order of amino acids.
- D.
All of the above.
Correct Answer
D. 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.Rate this question:
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- 3.
Catalase is a protein containing four heme groups, and it breaks down hydrogen peroxide into water and oxygen in the body. Using the table provided, what group of proteins does catalase most likely belong to?
- A.
Globular
- B.
Conjugated
- C.
Fibrous
- D.
None of them
Correct Answer
B. ConjugatedExplanation
Catalase is a protein that contains four heme groups, which are non-protein molecules that are bound to the protein. This indicates that catalase is a conjugated protein, as conjugated proteins are proteins that have non-protein components attached to them. Globular proteins are spherical in shape and typically have hydrophilic (water-loving) regions on the outside, while fibrous proteins are long and insoluble in water. Since catalase has non-protein heme groups attached to it, it is most likely a conjugated protein.Rate this question:
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- 4.
If you know that the percentage of (A) in one strand of a DNA molecule is 10% and that of (T) on the same strand is 20%. What is the percentage (C) in the double helix molecule?
- A.
10%
- B.
40%
- C.
35%
- D.
70%
Correct Answer
C. 35%Explanation
The percentage of (C) in the double helix molecule can be determined by subtracting the percentages of (A) and (T) from 100%. Since the percentage of (A) is 10% and the percentage of (T) is 20%, the combined percentage of (A) and (T) is 30%. Subtracting this from 100% gives us 70%, which represents the combined percentage of (G) and (C). Since (G) and (C) are always present in equal amounts in DNA, the percentage of (C) in the double helix molecule is half of 70%, which is 35%.Rate this question:
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- 5.
Albumin is found in …..
- A.
Plant’s roots
- B.
Plant’s leaves
- C.
Plasma of Blood
- D.
Saliva
Correct Answer
C. Plasma of BloodExplanation
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.Rate this question:
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- 6.
One of the following statements is not true for a dipeptide molecule ......
- A.
Two alkyl (R) groups
- B.
Two amino acids and one peptide bond.
- C.
Two free carboxylic groups and two free amino groups.
- D.
Amino acids are linked by a C-N bond.
Correct Answer
C. Two free carboxylic groups and two free amino groups.Explanation
A dipeptide molecule consists of two amino acids linked by a peptide bond. The peptide bond is formed between the carboxyl group of one amino acid and the amino group of the other amino acid. Therefore, there are not two free carboxylic groups and two free amino groups in a dipeptide molecule.Rate this question:
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- 7.
Which of the following best describes the tertiary structure of a protein?
- A.
The tertiary structure of a protein is the folded structure (alpha-helix or beta-sheet) formed by additional bonds that are formed in the polypeptide chain.
- B.
The tertiary structure of a protein is the complex 3D structure formed when multiple polypeptides interact and combine.
- C.
The tertiary structure of a protein refers to the sequence of amino acids in its polypeptide chain.
- D.
The tertiary structure of a protein is the 3D structure that forms due to interactions between the R groups of amino acids.
Correct Answer
D. The tertiary structure of a protein is the 3D structure that forms due to interactions between the R groups of amino acids.Explanation
The correct answer is the best description of the tertiary structure of a protein. The tertiary structure refers to the 3D structure that forms due to interactions between the R groups of amino acids. These interactions can include hydrogen bonding, disulfide bonds, hydrophobic interactions, and electrostatic interactions. The folding of the protein into its tertiary structure is crucial for its proper function and stability.Rate this question:
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- 8.
From the phosphoproteins we have ……….
- A.
Casein
- B.
Thyroxine
- C.
Insuline
- D.
Haemoglobin
Correct Answer
A. CaseinExplanation
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.Rate this question:
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- 9.
Identify each of the following test tubes, A, B, C and D ......
- A.
A iodine on starch / B benedict on glucose / C biuret on albumen / D sudan IV on palm oil.
- B.
A biuret on albumen / B benedict on glucose / C iodine on starch / D sudan IV on palm oil.
- C.
A iodine on starch / B biuret on albumen / C sudan IV on palm oil / D benedict on glucose
- D.
A biuret on albumen / B benedict on glucose / C sudan IV on palm oil / D iodine on starch.
Correct Answer
B. 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.Rate this question:
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- 10.
The diagram provided shows a simplified version of the different levels of structure of a protein. What are (1), (2), (3) & (4) respectively?
- A.
Quaternary, Secondary, Primary, Tertiary
- B.
Secondary, Quaternary, Primary, Tertiary
- C.
Primary, Secondary, Quaternary, Tertiary
- D.
Tertiary, Primary, Secondary, Quaternary
Correct Answer
A. Quaternary, Secondary, Primary, TertiaryExplanation
The correct answer is Quaternary, Secondary, Primary, Tertiary. The quaternary structure refers to the arrangement of multiple protein subunits to form a functional protein complex. The secondary structure refers to the local folding patterns of the polypeptide chain, such as alpha helices and beta sheets. The primary structure refers to the linear sequence of amino acids in a protein. The tertiary structure refers to the overall three-dimensional folding of a single polypeptide chain.Rate this question:
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- 11.
One of the following proteins does not match the classification of the other three ……
- A.
Casein
- B.
Thyroxine
- C.
Albumin
- D.
Haemoglobin
Correct Answer
C. AlbuminExplanation
Albumin is the correct answer because it is a protein that is found in blood plasma and is responsible for maintaining osmotic pressure. On the other hand, casein is a protein found in milk, thyroxine is a hormone produced by the thyroid gland, and hemoglobin is a protein found in red blood cells that carries oxygen. These three proteins have specific functions in the body, while albumin has a different role in maintaining blood pressure.Rate this question:
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- 12.
During prolonged fasting, in what sequence are the following organic compounds used up by the body?
- A.
First carbohydrates, next fats and lastly proteins
- B.
First fats, next carbohydrates and lastly proteins
- C.
First carbohydrates, next proteins and lastly fats
- D.
First proteins, next fats and lastly carbohydrates.
Correct Answer
A. First carbohydrates, next fats and lastly proteinsExplanation
During prolonged fasting, the body primarily relies on carbohydrates as its main source of energy. Once the carbohydrate stores are depleted, the body then starts breaking down fats to produce energy. Lastly, if the fasting continues for an extended period, the body starts breaking down proteins for energy. This sequence ensures that the body utilizes its energy sources in the most efficient manner, preserving proteins as much as possible.Rate this question:
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- 13.
Protein molecules are mostly made up of ………
- A.
Carbon, hydrogen, oxygen and nitrogen
- B.
Carbon, hydrogen, carbon monoxide and nitrogen
- C.
Carbon, hydrogen, oxygen and methane
- D.
Carbon, hydrogen, oxygen and sulpher
Correct Answer
A. Carbon, hydrogen, oxygen and nitrogenExplanation
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.Rate this question:
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- 14.
In double helix of DNA, the two DNA strands are .....
- A.
Coiled around a common axis
- B.
Coiled around each other
- C.
Coiled differently
- D.
Coiled over a cellulosic sheath.
Correct Answer
A. Coiled around a common axisExplanation
The correct answer is "Coiled around a common axis." In the double helix structure of DNA, the two DNA strands are coiled around a common axis, forming a twisted ladder-like structure. This coiling helps to stabilize the structure of DNA and allows for efficient packaging of genetic information within the cell.Rate this question:
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- 15.
Which of the following best explains the role of hydrogen bonds in protein structure?
- A.
Hydrogen bonds form within amino acids to join the carboxyl group to the amino group.
- B.
Hydrogen bonds form between amino acids to hold the protein in its secondary-structure shape
- C.
Hydrogen bonds form between amino acids to hold them in a polypeptide chain.
- D.
Hydrogen bonds form between amino acids and water molecules to contribute to the quaternary structure of the protein.
Correct Answer
B. Hydrogen bonds form between amino acids to hold the protein in its secondary-structure shapeExplanation
Hydrogen bonds play a crucial role in protein structure by forming between amino acids to hold the protein in its secondary-structure shape. Secondary structure refers to the folding patterns of the protein, including alpha helices and beta sheets. These hydrogen bonds form between the amino acid backbone, specifically between the carbonyl oxygen of one amino acid and the amino hydrogen of another amino acid. This stabilizes the protein structure and helps maintain its overall shape. Hydrogen bonds between amino acids in the polypeptide chain and water molecules do not directly contribute to the secondary structure, and hydrogen bonds within amino acids do not hold the protein in its secondary structure shape.Rate this question:
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- 16.
When trypsin enzyme is present in a sample, the biuret will turn _____.
- A.
Blue
- B.
Green
- C.
Violet
- D.
Orange
Correct Answer
C. VioletExplanation
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.Rate this question:
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- 17.
Each protein molecule is made up of …..
- A.
Carbohydrates
- B.
Fatty acids
- C.
Amino acids
- D.
Nucleotides
Correct Answer
C. Amino acidsExplanation
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.Rate this question:
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- 18.
Which of the following best describes the quaternary structure of a protein?
- A.
The quaternary structure of a protein is the 3D structure that forms due to interactions between the R groups of amino acids.
- B.
The quaternary structure of a protein is the folded structure formed by additional bonds formed in the polypeptide chain.
- C.
The quaternary structure of a protein is the complex 3D structure formed when multiple polypeptides interact and combine.
- D.
The quaternary structure of a protein refers to the sequence of amino acids in its polypeptide chain.
Correct Answer
C. The quaternary structure of a protein is the complex 3D structure formed when multiple polypeptides interact and combine.Explanation
The quaternary structure of a protein refers to the complex 3D structure formed when multiple polypeptides interact and combine. This structure is formed by the interactions between different polypeptide chains, which can be the same or different, and can involve various types of bonds such as hydrogen bonds, disulfide bonds, and hydrophobic interactions. The quaternary structure is essential for the protein's overall function and stability, as it determines how the different subunits come together to form a functional protein complex.Rate this question:
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- 19.
Which of the following foods has the lowest protein content?
- A.
1/2 cup (65 grams) pasta.
- B.
1 cup (150 grams) melon.
- C.
30 grams cheese.
- D.
1/2 cup (90 grams) cooked broccoli.
Correct Answer
B. 1 cup (150 grams) melon.Explanation
Melon has the lowest protein content among the given options because it is a fruit and fruits generally have lower protein content compared to other food groups. Pasta, cheese, and cooked broccoli all contain higher amounts of protein compared to melon.Rate this question:
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- 20.
There are about ……. amino acids in all which, can be linked together in different ways to make numerous protein molecules.
- A.
40
- B.
20
- C.
25
- D.
30
Correct Answer
B. 20Explanation
There are about 20 amino acids in all which can be linked together in different ways to make numerous protein molecules.Rate this question:
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- 21.
A segment of DNA has 120 adenine and 120 cytosine bases. The total number of nucleotides present in the segment is .....
- A.
120
- B.
240
- C.
360
- D.
480
Correct Answer
D. 480Explanation
The segment of DNA has 120 adenine bases and 120 cytosine bases, which means a total of 240 bases. Since each base is made up of a nucleotide, the total number of nucleotides present in the segment is also 240.Rate this question:
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- 22.
Assuming they all had the same number of carbon atoms, which of the following has the most C-H bonds?
- A.
Unsaturated fat
- B.
Dipeptide
- C.
Disaccharide
- D.
Saturated fat
Correct Answer
D. Saturated fatExplanation
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.Rate this question:
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- 23.
Which of the following structures can be formed when amino acids combine into specialized proteins in your body?
- A.
Enzymes, hormones, and ligaments
- B.
Hormones, DNA, and RNA
- C.
Tendons, glycogen, and DNA
- D.
Enzymes, RNA, and cholesterol
Correct Answer
A. Enzymes, hormones, and ligamentsExplanation
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.Rate this question:
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- 24.
The protein molecules inside the body are used for …....
- A.
Making new cells
- B.
Fighting microbes
- C.
Lowering heat of activation of the biochemical reactions
- D.
All of the above
Correct Answer
D. All of the aboveExplanation
Protein molecules inside the body have multiple functions. They are used for making new cells, which is essential for growth and repair. They also play a crucial role in fighting microbes by acting as antibodies and immune system components. Additionally, proteins act as enzymes, lowering the heat of activation of biochemical reactions, thus speeding up the rate of these reactions. Therefore, all the given options are correct, as protein molecules perform all of these functions in the body.Rate this question:
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- 25.
Dehydration and hydrolysis reactions involve removing or adding ______ to macromolecule subunits.
- A.
C and O
- B.
C and H
- C.
COOH and H
- D.
OH and H
Correct Answer
D. OH and HExplanation
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.Rate this question:
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- 26.
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.
- A.
Cα—N—C—Cα—N—C
- B.
Cα—N—C—C—N—Cα
- C.
C—N—Cα—Cα—C—N
- D.
Cα—C—N—Cα—C—N
Correct Answer
D. C&alpHa;—C—N—C&alpHa;—C—NExplanation
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.Rate this question:
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- 27.
The DNA …….
- A.
Store information for controlling all cellular activities.
- B.
Synthesizes fats.
- C.
Produces energy.
- D.
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.Rate this question:
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- 28.
All of the following are true for protein denaturation except that it ……
- A.
Is a shape change
- B.
Is always irreversible
- C.
May be caused by a pH change
- D.
Could result from a temperature change
Correct Answer
B. Is always irreversibleExplanation
Protein denaturation refers to the process in which a protein loses its native shape and structure. It can be caused by various factors such as pH change or temperature change. However, denaturation is not always irreversible. In some cases, proteins can regain their native conformation once the denaturing agent is removed. Therefore, the statement "Is always irreversible" is incorrect.Rate this question:
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- 29.
Which of the following best describes the secondary structure of a protein?
- A.
The secondary structure of a protein is the folded structure formed by additional bonds that are formed in the polypeptide chain.
- B.
The secondary structure of a protein is the 3D structure that forms due to interactions between the R groups of amino acids.
- C.
The secondary structure of a protein is the complex 3D structure formed when multiple polypeptides interact and combine.
- D.
The secondary structure of a protein refers to the sequence of amino acids in its polypeptide chain.
Correct Answer
A. The secondary structure of a protein is the folded structure formed by additional bonds that are formed in the polypeptide chain.Explanation
The correct answer is the first option. The secondary structure of a protein refers to the folded structure that is formed by additional bonds within the polypeptide chain. This structure is typically stabilized by hydrogen bonds between the amino acid residues. Examples of secondary structures include alpha helices and beta sheets. The 3D structure of a protein, on the other hand, is referred to as the tertiary structure, which is determined by interactions between the R groups of amino acids. The other options do not accurately describe the secondary structure of a protein.Rate this question:
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- 30.
The DNA consists of two …….. coiled strands.
- A.
Spherically
- B.
Spirally
- C.
Angularly
- D.
Cubically
Correct Answer
B. SpirallyExplanation
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.Rate this question:
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- 31.
Small molecules are used as the basic units in the synthesis of large food molecules. Which of the following statements is correct?
- A.
Amino acids are basic units of carbohydrates
- B.
Fatty acids are basic units of glycogen
- C.
Glycerol is a basic unit of oils
- D.
Simple sugar is a basic unit of protein
Correct Answer
C. Glycerol is a basic unit of oilsExplanation
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.Rate this question:
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- 32.
What type of macromolecule carries out catalysis in biological systems?
- A.
Proteins called enzymes
- B.
Carbohydrates called starches
- C.
Lipids called steroids
- D.
Nucleic acids called DNA
Correct Answer
A. Proteins called enzymesExplanation
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.Rate this question:
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- 33.
A nucleotide has ……….
- A.
Nitrogenous base + phosphoric acid + sugar
- B.
Two sugar molecules + phosphoric acid
- C.
Three phosphoric acid molecules
- D.
Two phosphoric acid + nitrogenous base
Correct Answer
A. Nitrogenous base + pHospHoric acid + sugarExplanation
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.Rate this question:
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- 34.
Polymerization reactions in which polysaccharides are synthesized from monosaccharides or proteins are synthesized from amino acids. These reactions …...
- A.
Are hydrolysis reactions.
- B.
Result in the formation of water.
- C.
Release energy.
- D.
All of the above.
Correct Answer
B. Result in the formation of water.Explanation
Polymerization reactions in which polysaccharides are synthesized from monosaccharides or proteins are synthesized from amino acids result in the formation of water. This is because during the polymerization process, a molecule of water is released for each bond that is formed between the monomers. Therefore, the correct answer is that these reactions result in the formation of water.Rate this question:
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- 35.
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)
- A.
3
- B.
5
- C.
6
- D.
9
Correct Answer
C. 6Explanation
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.Rate this question:
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- 36.
Which element occurs in nucleic acids?
- A.
Manganese
- B.
Calcium
- C.
Phosphorus
- D.
Sulfur
Correct Answer
C. pHospHorusExplanation
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.Rate this question:
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- 37.
In a DNA molecule, adenine binds with thymine by a …..
- A.
Single bond
- B.
Double bond
- C.
Triple bond
- D.
Ionic bond
Correct Answer
B. Double bondExplanation
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.Rate this question:
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- 38.
Why does the hydrolysis of histones produce amino acids only?
- A.
Because DNA molecules are coiled around different histone subunits
- B.
Because histones are simple proteins
- C.
Because histones are soluble in water
- D.
Because histones are basic proteins
Correct Answer
B. Because histones are simple proteinsExplanation
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.Rate this question:
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- 39.
DNA is composed of repeating units of ………
- A.
Ribonucleosides
- B.
Ribonucleotides
- C.
Deoxyribonucleosides
- D.
Deoxyribonucleotides.
Correct Answer
D. 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.Rate this question:
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- 40.
The diagram shows two adjacent nucleotides joined together via a bond (X). What does the bond (X) represent?
- A.
Glycosidic
- B.
Hydrogen
- C.
Phosphodiester
- D.
Peptide
Correct Answer
C. pHospHodiesterExplanation
The bond (X) in the diagram represents a phosphodiester bond. This type of bond is formed between the phosphate group of one nucleotide and the sugar group of another nucleotide in a nucleic acid molecule. It is a strong covalent bond that links the nucleotides together to form the backbone of DNA and RNA strands.Rate this question:
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- 41.
In the formation of a macromolecule, what type of bond would join two amino acid subunits?
- A.
Ionic bond
- B.
Bond between two carbon atoms
- C.
Hydrogen bond
- D.
Peptide bond
Correct Answer
D. Peptide bondExplanation
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.Rate this question:
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- 42.
Each of the hooves and horns consists of different proteins, due to the difference in the ………… in their building units.
- A.
Number of water molecules that are present
- B.
Alkyl groups
- C.
Free carboxylic groups
- D.
Free amino groups
Correct Answer
B. Alkyl groupsExplanation
Hooves and horns are made up of proteins, which are composed of building units called amino acids. The difference in the composition of hooves and horns is due to the difference in the alkyl groups present in their amino acids. Alkyl groups are hydrocarbon chains that can vary in length and branching, and their presence in amino acids contributes to the unique properties of the proteins found in hooves and horns.Rate this question:
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- 43.
Keratin is a long protein found in hair and nails, with many repeats of the sulfur-containing amino acid cysteine. Using the table provided, determine the group of proteins that keratin is most likely to belong to.
- A.
Globular
- B.
Fibrous
- C.
Conjugated
- D.
None
Correct Answer
B. FibrousExplanation
Keratin is described as a long protein found in hair and nails, with many repeats of the sulfur-containing amino acid cysteine. This description suggests that keratin has a structural role and is involved in providing strength and elasticity to hair and nails. Fibrous proteins are known for their structural functions, forming long, filamentous structures. Therefore, it is reasonable to conclude that keratin is most likely to belong to the group of fibrous proteins.Rate this question:
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- 44.
In a DNA molecule, cytosine binds with guanine by a ……
- A.
Single bond
- B.
Double bond
- C.
Triple bond
- D.
Ionic bond
Correct Answer
C. Triple bondExplanation
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.Rate this question:
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- 45.
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?
- A.
One chain
- B.
Two chains
- C.
Three chains
- D.
Six chains
Correct Answer
A. One chainExplanation
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.Rate this question:
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- 46.
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?
- A.
Simple sugars
- B.
Conjugated proteins
- C.
Derived lipids
- D.
Complex sugars
Correct Answer
D. Complex sugarsExplanation
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.Rate this question:
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- 47.
Which of these bonds is found between complementary base pairs in DNA?
- A.
Ionic
- B.
Glycosidic
- C.
Phosphodiester
- D.
Hydrogen
Correct Answer
D. HydrogenExplanation
Hydrogen bonds are the bonds found between complementary base pairs in DNA. These bonds occur between the nitrogenous bases adenine (A) and thymine (T), as well as between guanine (G) and cytosine (C). Hydrogen bonds are relatively weak compared to covalent bonds, but they play a crucial role in maintaining the structure and stability of the DNA double helix. The hydrogen bonds between base pairs allow for the separation and replication of DNA strands during cellular processes such as DNA replication and transcription.Rate this question:
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- 48.
Which of the following contain nitrogen and sulphur?
- A.
Nucleic acids
- B.
Carbohydrates
- C.
Lipids
- D.
Proteins
Correct Answer
D. ProteinsExplanation
Proteins contain both nitrogen and sulfur. Nitrogen is found in the amino acids that make up proteins, while sulfur is present in certain amino acids such as cysteine and methionine. These elements play important roles in the structure and function of proteins, contributing to their unique properties and functions in the body.Rate this question:
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- 49.
Nucleotides have a nitrogenous base attached to a sugar at the …...
- A.
1' carbon
- B.
2' carbon
- C.
3' carbon
- D.
5' carbon
Correct Answer
A. 1' carbonExplanation
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.Rate this question:
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- 50.
Which of the following can be used as short-term energy storage?
- A.
Carbohydrates
- B.
Triglycerides
- C.
ATP
- D.
Proteins
Correct Answer
C. ATPExplanation
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.Rate this question:
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Current Version
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Mar 09, 2023Quiz Edited by
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Jul 31, 2020Quiz Created by
Samy
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