Bio 103 5th Chapter

1.

Which of the following categories includes all others in the list ?
- A.
  
  Disaccharide
- B.
  
  Polysaccharide
- C.
  
  Starch
- D.
  
  Carbohydrate
Correct Answer
D. Carbohydrate

Explanation
Carbohydrate is the correct answer because it is the broadest category that includes all the other categories mentioned in the list. Disaccharide and polysaccharide are subcategories of carbohydrates, as they are both types of sugars made up of multiple sugar molecules. Starch is a specific type of polysaccharide, which is a complex carbohydrate found in plants. Therefore, carbohydrate is the most inclusive category that encompasses all the other options.

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2.

Which of the following is true of unsaturated fats ?
- A.
  
  They are more common in animals than in plant
- B.
  
  They have double bonds in their fatty-acid chains
- C.
  
  They generally solidify at room temperature
- D.
  
  Two answers are correct
Correct Answer
B. They have double bonds in their fatty-acid chains

Explanation
Unsaturated fats are true for having double bonds in their fatty-acid chains. Unsaturated fats are typically found in plant-based sources and are liquid at room temperature. These fats are considered healthier than saturated fats because they can help lower bad cholesterol levels in the body. Conversely, saturated fats, which are more common in animal-based sources, do not have double bonds in their fatty-acid chains and are generally solid at room temperature. Therefore, the correct answer is that unsaturated fats have double bonds in their fatty-acid chains.

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3.

Enzyme that break down DNA catalyze the hydrolysis of the covalent bonds that join uncleotides together .What would happen to DNA molecule treated with these enzymes ?
- A.
  
  The two strands of the double helix would separate
- B.
  
  The phosphodiester linkage of the polynucleotide backbone would be broken
- C.
  
  The pyrimidine would be separated from the deoxyribose sugars
- D.
  
  All bases would be separated from the deoxyribose sugars
Correct Answer
B. The phosphodiester linkage of the polynucleotide backbone would be broken

Explanation
The correct answer states that the phosphodiester linkage of the polynucleotide backbone would be broken if DNA is treated with enzymes that break down DNA. This is because these enzymes catalyze the hydrolysis of the covalent bonds that join nucleotides together, specifically the phosphodiester bonds. Breaking these bonds would result in the separation of the two strands of the DNA double helix.

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4.

Which of the following is a sugar?
- A.
  
  C5H12O6
- B.
  
  C8H16O16
- C.
  
  C4H8O4
- D.
  
  C12H12O12
Correct Answer
C. C4H8O4

Explanation
The correct answer is C4H8O4. This compound has the chemical formula C4H8O4, indicating that it contains 4 carbon atoms, 8 hydrogen atoms, and 4 oxygen atoms. This formula corresponds to a sugar known as succinic acid, which is a dicarboxylic acid commonly found in the body as an intermediate in the citric acid cycle. It is also used as a food additive and in the production of certain polymers.

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5.

Which of the following pairs of base sequences could form a short stretch of a normal double helix of DNA?
- A.
  
  5' -AGCT- 3' with 5' -TCGA- 3'
- B.
  
  5' -GCGC- 3' with 5' -ATAT- 3'
- C.
  
  5' -ATGC- 3' with 5'-GCAT-3'
- D.
  
  All the above
Correct Answer
C. 5' -ATGC- 3' with 5'-GCAT-3'

Explanation
The correct answer is 5' -ATGC- 3' with 5'-GCAT-3'. This is because in DNA, adenine (A) always pairs with thymine (T), and guanine (G) always pairs with cytosine (C). Therefore, the base sequence 5' -ATGC- 3' can pair with its complementary sequence 5'-GCAT-3', forming a short stretch of a normal double helix of DNA. The other pairs of base sequences do not follow the complementary base pairing rule and cannot form a normal double helix of DNA.

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6.

What is the reaction that break down the molecules by adding a water molecule ?
- A.
  
  Hydrolysis
- B.
  
  Dehydration
- C.
  
  Polymerization
- D.
  
  All the above
Correct Answer
A. Hydrolysis

Explanation
Hydrolysis is the correct answer because it is a chemical reaction that breaks down molecules by adding a water molecule. This process occurs when a water molecule is split into its components, hydrogen and hydroxide ions, which then interact with the molecules being broken down, causing them to separate into smaller components. This reaction is commonly observed in biological processes such as digestion, where large molecules are broken down into smaller ones to be absorbed by the body. Dehydration and polymerization, on the other hand, involve the removal of water molecules and the formation of larger molecules, respectively, making them incorrect choices.

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7.

A sugar with the molecular formula C6H12O6 .what would be the molecular formula for a polymer made by linking 10 of this sugar by dehydration reactions?
- A.
  
  C60H120O60
- B.
  
  C60H102O51
- C.
  
  C60H100O50
- D.
  
  C60H111O51
Correct Answer
B. C60H102O51

Explanation
When 10 molecules of the sugar with the molecular formula C6H12O6 are linked together through dehydration reactions, water molecules are eliminated. Each sugar molecule loses one water molecule during the dehydration reaction. Since there are 10 sugar molecules being linked together, there will be 10 water molecules eliminated. Therefore, the resulting polymer will have 10 fewer hydrogen atoms and 10 fewer oxygen atoms compared to the sum of the individual sugar molecules. Hence, the molecular formula for the polymer would be C60H102O51.

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8.

Which of the following types of lipid consist of: 3 fatty acids + glycerol
- A.
  
  Fats
- B.
  
  Phosphlipids
- C.
  
  Stroid
- D.
  
  Non of the above
Correct Answer
A. Fats

Explanation
Fats consist of three fatty acids attached to a glycerol molecule. This combination forms a triglyceride, which is the most common type of lipid found in the body. Triglycerides serve as a major source of energy and are also involved in storing energy for later use. Therefore, the correct answer is fats.

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9.

Which of the following can't digest by animal enzyme ?
- A.
  
  Chitin
- B.
  
  Cellulose
- C.
  
  Starch
- D.
  
  Glycogen
Correct Answer
B. Cellulose

Explanation
Cellulose cannot be digested by animal enzymes because animals lack the necessary enzyme, called cellulase, to break down the complex structure of cellulose. Cellulose is a type of carbohydrate found in the cell walls of plants and provides structural support. While animals can digest other carbohydrates like starch and glycogen, they are unable to break down the bonds in cellulose, making it indigestible for them.

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10.

Which level of protein structure do the alpha helix and bata pleated sheet represent ?
- A.
  
  Primary
- B.
  
  Secondary
- C.
  
  Tertiary
- D.
  
  Quaternary
- E.
  
  All the above
Correct Answer
B. Secondary

Explanation
The alpha helix and beta pleated sheet represent the secondary level of protein structure. The secondary structure refers to the regular patterns of folding within a protein, such as the helical shape of the alpha helix or the sheet-like structure of the beta pleated sheet. The primary structure refers to the linear sequence of amino acids, while the tertiary structure refers to the overall 3D shape of the protein. The quaternary structure refers to the arrangement of multiple protein subunits.

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11.

To which carbon does the phosphate group linked ?
- A.
  
  3
- B.
  
  5
- C.
  
  1
- D.
  
  6
Correct Answer
B. 5

Explanation
The phosphate group is linked to carbon number 5.

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Bio 103 5th Chapter

Which of the following categories includes all others in the list ?

Which of the following is true of unsaturated fats ?

Enzyme that break down DNA catalyze the hydrolysis of the covalent bonds that join uncleotides together .What would happen to DNA molecule treated with these enzymes ?

Which of the following is a sugar?

Which of the following pairs of base sequences could form a short stretch of a normal double helix of DNA?

What is the reaction that break down the molecules by adding a water molecule ?

A sugar with the molecular formula C6H12O6 .what would be the molecular formula for a polymer made by linking 10 of this sugar by dehydration reactions?

Which of the following types of lipid consist of: 3 fatty acids + glycerol

Which of the following can't digest by animal enzyme ?

Which level of protein structure do the alpha helix and bata pleated sheet represent ?

To which carbon does the phosphate group linked ?