1.
What enzyme destroys protein?
Correct Answer
D. Protease
Explanation
Protease is an enzyme that breaks down proteins by hydrolyzing the peptide bonds between amino acids. It plays a crucial role in various biological processes, including digestion, protein turnover, and regulation of cellular functions. Proteases are found in all living organisms and are essential for maintaining protein homeostasis. They can be classified into different types based on their specificity and mechanism of action. Therefore, protease is the correct answer as it is specifically responsible for protein degradation.
2.
What enzyme destroys DNA?
Correct Answer
A. DNAase
Explanation
DNAase is the correct answer because it is an enzyme that specifically breaks down DNA molecules. It catalyzes the hydrolysis of the phosphodiester bonds between nucleotides in DNA, leading to the degradation of the DNA molecule. RNAase, ribose, protease, and bacteriophages do not have the specific function of destroying DNA.
3.
What experimental batch resulted in the mice surviving? (You must select three correct answers.)
Correct Answer(s)
B. Heat-killed S cells
C. DNAse
E. Live R cells
Explanation
The mice survived when they were exposed to heat-killed S cells, DNAse, and live R cells. Heat-killed S cells are unable to cause infection, so the mice were not harmed. DNAse breaks down DNA, which may have prevented the harmful effects of the experiment. Live R cells did not cause infection in the mice, leading to their survival.
4.
In Avery's experiment, R cells were transformed into_____.
Correct Answer
C. S cells
Explanation
In Avery's experiment, R cells were transformed into S cells. This suggests that the S cells contain a substance that can transform the R cells. This substance is most likely DNA, as DNA is known to carry genetic information and can be transferred between cells through a process called transformation. Therefore, the correct answer is S cells.
5.
Select the four nitrogenous bases found in the DNA nucleotides from the list below. (Please note that all four answers must be correct to receive credit.)
Correct Answer(s)
B. Cytosine
C. Guanine
D. Adenine
E. Thymine
Explanation
The correct answer is Cytosine, Guanine, Adenine, and Thymine. These four nitrogenous bases are found in DNA nucleotides. Uracil is found in RNA nucleotides, not DNA. Ribosine and Deoxyribosine are not nitrogenous bases. Therefore, the correct answer is Cytosine, Guanine, Adenine, and Thymine.
6.
G is to guanine as C is to_____.
Correct Answer
C. Cytosine
Explanation
Guanine and cytosine are two of the four nucleotide bases that make up DNA. They are often paired together in a DNA molecule, with guanine always pairing with cytosine. Therefore, the correct analogy is that G is to guanine as C is to cytosine. Adenine and thymine are the other two nucleotide bases that pair together in DNA.
7.
In the DNA molecule chain Adenine uses hydrogen bonds to_____? (Please enter your answer with a capital letter.)
Correct Answer
Thymine
Explanation
Adenine uses hydrogen bonds to pair with Thymine in the DNA molecule chain. Hydrogen bonding is a type of chemical bond in which a hydrogen atom is attracted to an electronegative atom, such as oxygen or nitrogen. In DNA, Adenine always pairs with Thymine through two hydrogen bonds, forming a complementary base pair. This pairing is crucial for the stability and replication of the DNA molecule.
8.
Select nucleotides for the DNA molecule which are classified as purines.
Correct Answer(s)
A. Adenine
B. Guanine
Explanation
Adenine and guanine are classified as purines because they have a double-ring structure. Purines are one of the two types of nitrogenous bases found in DNA, the other being pyrimidines. Adenine and guanine form base pairs with thymine and cytosine, respectively, in DNA. Uracil is a pyrimidine and is not found in DNA, but instead in RNA. Therefore, the nucleotides adenine and guanine are classified as purines.
9.
Select nucleotides for the DNA and/or RNA molecules which are classified as pyrmidines.
Correct Answer(s)
C. Cytosine
D. Thymine
E. Uracil
Explanation
The correct answer includes the nucleotides Cytosine, Thymine, and Uracil. These nucleotides are classified as pyrimidines. Pyrimidines are a type of nitrogenous base that consists of a single-ring structure. They are one of the two categories of nucleotides, the other being purines. Adenine and Guanine, on the other hand, are classified as purines as they have a double-ring structure. Therefore, the correct answer includes the nucleotides that belong to the pyrimidine category.
10.
_____ is a nitrogenous base found in RNA in positions analogous to the thymine in DNA. It is based on a pyrimidine ring structure. (Please enter your answer starting with a capital letter.)
Correct Answer(s)
Uracil
Explanation
Uracil is a nitrogenous base found in RNA in positions analogous to the thymine in DNA. It is based on a pyrimidine ring structure. Uracil replaces thymine in RNA and forms base pairs with adenine during RNA synthesis. Unlike thymine, uracil does not contain a methyl group, making it more reactive and prone to mutations.
11.
Guanine is a nitrogenous base found in nucleic acids and nucleosides. It is based on a pyrimidine ring structure with double ring of carbon and nitrogen.
Correct Answer
B. False
Explanation
The explanation for the answer "False" is that guanine is not based on a pyrimidine ring structure with a double ring of carbon and nitrogen. Instead, it is based on a purine ring structure, which consists of a double ring of carbon and nitrogen atoms.
12.
Using the base-pairing rules to determine the base sequence that is complementary to the sequence A C C T G A G T A.
Correct Answer
A. T G G A C T C A T
Explanation
The given sequence A C C T G A G T A can be paired with its complementary sequence by following the base-pairing rules. Adenine (A) pairs with Thymine (T) and Cytosine (C) pairs with Guanine (G). Therefore, the complementary sequence for A C C T G A G T A is T G G A C T C A T.
13.
You have been presented with an image of two nitrogenous bases found in the DNA molecule. It is the base-pairing correct?
Correct Answer
A. True
Explanation
The image of two nitrogenous bases found in the DNA molecule suggests that they are correctly paired. In DNA, the bases always pair in a specific way: adenine (A) with thymine (T), and cytosine (C) with guanine (G). Based on the image, if the two bases are paired in this manner, it indicates the correct base-pairing in DNA. Therefore, the answer is true.
14.
In the image below of nitrogenous bases, how many hydrogen bonds are present in the base-pairing of cytosine and guanine?
Correct Answer
C. Three
Explanation
Cytosine and guanine form a base pair in DNA and RNA, and they are held together by three hydrogen bonds. The hydrogen bonds between cytosine and guanine contribute to the stability and structure of the DNA double helix.
15.
_____ was to show that in natural DNA the number of guanine units equals the number of cytosine units and the number of adenine units equals the number of thymine units.
Correct Answer
A. Chargaff, Erwin
Explanation
Chargaff, Erwin was the scientist who discovered the base pairing rules in DNA. He found that the amount of guanine (G) is equal to the amount of cytosine (C), and the amount of adenine (A) is equal to the amount of thymine (T). This discovery, known as Chargaff's rules, provided crucial evidence for the structure of DNA and its ability to replicate accurately.