1.
The structure of DNA is described as _______________.
Correct Answer
B. A double stranded helix
Explanation
The structure of DNA is described as a double stranded helix because it consists of two strands that are twisted around each other in a spiral shape. This helical structure allows the DNA molecule to be compact and stable, while also providing a mechanism for easy replication and transmission of genetic information.
2.
A nucleotide consists of a ________, _________, and _________.
Correct Answer
A. Sugar, pHospHate, and base
Explanation
A nucleotide is composed of three components: a sugar molecule, a phosphate group, and a nitrogenous base. The sugar molecule provides the backbone of the nucleotide, the phosphate group connects the sugar molecules together, and the nitrogenous base attaches to the sugar molecule. Oxygen is present in the sugar molecule, but it is not one of the three main components of a nucleotide.
3.
DNA is found inside the __________of eukaryotic cells.
Correct Answer
D. Nucleus
Explanation
DNA is found inside the nucleus of eukaryotic cells. The nucleus is the control center of the cell and contains the genetic material, including DNA. This is where DNA replication, transcription, and other important cellular processes related to DNA occur. The other options, such as endoplasmic reticulum, ribosome, and cytoplasm, do not contain DNA.
4.
The structure of DNA was successfully discovered by ______________.
Correct Answer
B. Watson and Crick
Explanation
Watson and Crick successfully discovered the structure of DNA. They proposed the double helix model in 1953, which explained how DNA is composed of two strands that are twisted together in a spiral shape. Their discovery was based on the work of other scientists, including Rosalind Franklin's X-ray crystallography images of DNA. Watson and Crick's model provided a breakthrough understanding of how genetic information is stored and passed on in living organisms.
5.
During DNA replication, which enzyme is responsible for breaking the hydrogen bonds between the base pairs.
Correct Answer
C. Helicase
Explanation
Helicase is the enzyme responsible for breaking the hydrogen bonds between the base pairs during DNA replication. This enzyme unwinds the double helix structure of DNA by breaking the hydrogen bonds, allowing the DNA strands to separate and serve as templates for the synthesis of new DNA strands. Helicase plays a crucial role in the process of DNA replication by ensuring that the DNA strands are properly separated and accessible for replication to occur.
6.
Where does transcription occur inside the cell?
Correct Answer
A. Nucleus
Explanation
Transcription is the process of synthesizing RNA from a DNA template. It occurs inside the nucleus of a cell. This is because the nucleus contains the DNA, which serves as the template for RNA synthesis. The RNA molecules that are produced during transcription are then transported out of the nucleus and into the cytoplasm, where they can undergo further processing and translation to produce proteins. The ribosome, although involved in protein synthesis, is not the site of transcription. Therefore, the correct answer is the nucleus.
7.
In a DNA molecule, which base always pairs up with Adenine?
Correct Answer
B. Thymine
Explanation
Thymine always pairs up with Adenine in a DNA molecule. This is because of the complementary base pairing rule in DNA. Adenine forms two hydrogen bonds with Thymine, creating a stable base pair. This pairing is essential for DNA replication and the transmission of genetic information. Guanine pairs up with Cytosine in a similar manner.
8.
What is the complementary side to this DNA molecule?
ATTCCGG
Correct Answer
B. TAAGGCC
Explanation
The complementary side to a DNA molecule refers to the sequence of nucleotides that can pair with the given sequence through base pairing rules. In DNA, adenine (A) pairs with thymine (T), and cytosine (C) pairs with guanine (G). Therefore, the complementary side to the DNA molecule ATTCCGG would be TAAGGCC, as it follows the base pairing rules.
9.
How many bases make up a codon?
Correct Answer
C. 3
Explanation
A codon is a sequence of three nucleotides that codes for a specific amino acid or a stop signal during protein synthesis. In the genetic code, there are a total of 64 possible codons. Since each codon is made up of three bases, the correct answer is 3.
10.
Which type of mutation is shown below?
Original DNA: ATTACCG
Mutated DNA: ATTCCG
Correct Answer
C. Frameshift Deletion
Explanation
The mutated DNA sequence shows a deletion of one nucleotide, resulting in a frameshift mutation. A frameshift mutation occurs when the reading frame of the genetic code is disrupted, usually by an insertion or deletion of nucleotides. In this case, the deletion of one nucleotide shifts the reading frame, causing a change in the amino acid sequence that follows the mutation. This is different from a point mutation, which involves the substitution of a single nucleotide.