1.
Miescher discovered nuclein, a new class of organic molecule. Today we call it nucleic acid. He knew it was not protein because it had the element:
Correct Answer
E. pHospHorus
Explanation
Miescher discovered nuclein, which is now known as nucleic acid. He determined that it was not a protein because it contained phosphorus, which is not found in proteins. Proteins are composed of carbon, hydrogen, oxygen, and nitrogen, but the presence of phosphorus in nuclein indicated that it was a different type of organic molecule. This discovery laid the foundation for our understanding of nucleic acids and their role in genetics.
2.
Miescher discovered nuclein, a new class of organic molecule. Today we call it nucleic acid. He knew it was not protein because it did not have the element:
Correct Answer
S
sulfur
sulphur
Explanation
Miescher discovered nuclein, a new class of organic molecule known today as nucleic acid. He determined that it was not a protein based on the absence of the element sulfur (S) or sulphur. Proteins typically contain sulfur in their amino acid composition, whereas nucleic acids, such as DNA and RNA, do not. Therefore, the absence of sulfur in nuclein indicated that it was a different type of molecule, leading to the discovery of nucleic acids.
3.
Avery, MacLeod, and McCarty showed that ______ of IIIS bacteria was capable of transforming live IIR bacteria in to live IIIS bacteria.
Correct Answer
DNA
deoxyribonucleic acid
the DNA
the deoxyribonucleic acid
Explanation
Avery, MacLeod, and McCarty showed that DNA (deoxyribonucleic acid) of IIIS bacteria was capable of transforming live IIR bacteria into live IIIS bacteria.
4.
In Griffith's 1928 experiment, when live IIR bacteria and heat-killed IIIS bacteria were injected a mouse:
Correct Answer
B. The IIR bacteria were transformed into IIIS bacteria.
Explanation
In Griffith's 1928 experiment, the injection of live IIR bacteria and heat-killed IIIS bacteria resulted in the transformation of the IIR bacteria into IIIS bacteria. This transformation was observed in the mouse, indicating that some factor from the heat-killed bacteria had been transferred to the live bacteria, allowing them to gain the ability to cause disease. This result was significant as it suggested the presence of a transforming principle, later identified as DNA, which carries genetic information and can be transferred between bacteria.
5.
DNA has a deoxribose - _______ backbone.
Correct Answer
phosphate
PO4
Explanation
The DNA molecule consists of two strands that are held together by a backbone. This backbone is made up of alternating deoxyribose sugar molecules and phosphate groups. The phosphate group, which is represented by the chemical formula PO4, forms the "backbone" of the DNA molecule. It provides stability and structure to the DNA molecule, allowing it to maintain its double helix shape. Therefore, the correct answer is phosphate, represented by PO4.
6.
The 3' oxygen of deoxyribose of a DNA nucleotide is linked the ___' oxygen of deoxyribose of the adjacent nucleotide by way of a phosphate group. (The answer is a number.)
Correct Answer
5
5'
Explanation
The 3' oxygen of deoxyribose of a DNA nucleotide is linked to the 5' oxygen of deoxyribose of the adjacent nucleotide by way of a phosphate group.
7.
The pyrimidines found in DNA are cytosine and _______.
Correct Answer
thymine
Explanation
The pyrimidines found in DNA are cytosine and thymine. Thymine is one of the four nucleotide bases that make up DNA, along with adenine, guanine, and cytosine. These bases pair up with each other in a specific way, with adenine always pairing with thymine. Thymine plays a crucial role in the structure and function of DNA, as it forms hydrogen bonds with adenine to create the double helix structure of the DNA molecule. Therefore, thymine is a vital component of DNA and is always found alongside cytosine in the DNA molecule.
8.
[The nitrogen base on the right is _______.
Correct Answer
thymine
Explanation
The nitrogen base on the right is thymine. Thymine is one of the four nitrogenous bases found in DNA. It pairs with adenine through hydrogen bonding, forming a base pair that stabilizes the DNA double helix structure. Thymine is a pyrimidine base, meaning it has a single-ring structure. It is specifically found in DNA and is not present in RNA, where it is replaced by uracil.
9.
If a frog's DNA consists of 23% adenine, then the percent of guanine is _____%.
Correct Answer
27
27%
Explanation
The percentage of guanine in DNA is always equal to the percentage of cytosine. Since adenine and thymine always pair up in DNA, the total percentage of adenine and thymine is 50%. Therefore, the percentage of guanine and cytosine combined is also 50%. If the percentage of adenine is 23%, then the percentage of guanine is also 23%.
10.
Watson and Crick used the X-ray diffraction data of Wilkins and _______. (last name)
Correct Answer
Franklin
Explanation
Watson and Crick used the X-ray diffraction data of Wilkins and Franklin.
11.
DNA's two strands run in opposite directions. That is, DNA is _______.
Correct Answer
antiparallel
Explanation
DNA's two strands run in opposite directions, meaning that one strand runs in the 5' to 3' direction while the other runs in the 3' to 5' direction. This arrangement is referred to as antiparallel.
12.
A DNA double helix 30 base pairs long would be ____Å long. (The answer is a number.)
Correct Answer
102
one hundred two
one hundred and two
a hundred and two
a hundred two
Explanation
A DNA double helix is composed of two strands that are twisted together. Each base pair in the helix is approximately 3.4 angstroms (Å) long. Therefore, to determine the length of a DNA double helix, we multiply the number of base pairs by 3.4. In this case, since the helix is 30 base pairs long, the length would be 30 * 3.4 = 102 Å.
13.
On opposite sides of a DNA double helix there are grooves: a larger groove and a smaller groove. The smaller groove is called the _______ groove.
Correct Answer
minor
Explanation
The smaller groove on opposite sides of a DNA double helix is called the minor groove. This groove is narrower and less accessible compared to the larger groove. It plays a crucial role in DNA-protein interactions and is involved in the recognition and binding of specific proteins to the DNA molecule. The minor groove provides important structural information and contributes to the overall stability and function of the DNA molecule.