1.
What is the Y-shaped region that results when the two strands separate called?
Correct Answer
B. Replication Fork
Explanation
The Y-shaped region that results when the two strands of DNA separate is called the replication fork. During DNA replication, the double helix structure of DNA unwinds and the two strands separate, forming a replication fork. This is where the new DNA strands are synthesized using the existing strands as templates. The replication fork moves along the DNA molecule as replication proceeds, creating two identical copies of the original DNA molecule.
2.
_____ - _____ replication will produce two copies that each contained one of the original strands and one new strand.
Correct Answer
Semi-conservative
semi-conservative
Explanation
Semi-conservative replication refers to the process in which the DNA molecule is replicated, resulting in two copies, with each copy containing one of the original strands and one newly synthesized strand. This means that during replication, the two strands of the DNA molecule separate, and each strand serves as a template for the synthesis of a new complementary strand. Therefore, the correct answer is "Semi-conservative, semi-conservative."
3.
Mutation is a change in the nucleotide sequence of a RNA molecule. Mutations can't have any serious effects on important gene functions.
Correct Answer
B. False
Explanation
Mutations can have serious effects on important gene functions. Mutations can alter the amino acid sequence of a protein, leading to changes in its structure and function. This can result in various genetic disorders and diseases. Additionally, mutations can also affect regulatory regions of genes, leading to changes in gene expression levels. Therefore, mutations can indeed have significant and sometimes detrimental effects on important gene functions.
4.
Ribonucleic Acid molecules functions in various forms to translate the information contained in DNA molecules into proteins.
Correct Answer
A. True
Explanation
Ribonucleic Acid (RNA) molecules play a crucial role in the process of protein synthesis. They are responsible for translating the genetic information stored in DNA molecules into proteins. This process, known as transcription and translation, involves the RNA molecules binding to the DNA template and using it as a guide to produce a complementary RNA sequence. This RNA sequence, called messenger RNA (mRNA), is then used as a template by the ribosomes to synthesize proteins. Therefore, it is true that RNA molecules function in various forms to translate the information contained in DNA molecules into proteins.
5.
_____ is the first step of gene expression, in which a particular segment of DNA is copied into RNA by the enzyme RNA polymerase.
Correct Answer
A. Transcription
Explanation
Transcription is the process of gene expression where a specific segment of DNA is copied into RNA by the enzyme RNA polymerase. This is the first step in gene expression and is essential for the production of proteins. During transcription, the DNA sequence is transcribed into a complementary RNA molecule, which can then be used as a template for translation to produce proteins.
6.
_____ is the process through which cellular ribosomes manufacture proteins, in which messenger RNA (mRNA) is sequentially decoded by transfer RNA (tRNA).
Correct Answer
Translation
translation
Explanation
Translation is the process through which cellular ribosomes manufacture proteins, in which messenger RNA (mRNA) is sequentially decoded by transfer RNA (tRNA). This process involves the conversion of the genetic information encoded in the mRNA into a specific sequence of amino acids, which ultimately determines the structure and function of the resulting protein. The ribosomes read the mRNA molecule and match each codon with the corresponding anticodon on the tRNA molecule, which carries the specific amino acid. As the ribosome moves along the mRNA, it synthesizes the protein by joining the amino acids together in the correct order.
7.
_____ synthesis is the process by which biological cells generate new _____. The assembly of proteins by ribosomes is an essential part of the biosynthetic pathway.
Correct Answer
E. Protein, proteins
Explanation
Protein synthesis is the process by which biological cells generate new proteins. The assembly of proteins by ribosomes is an essential part of the biosynthetic pathway. This process involves the translation of the genetic information encoded in mRNA into a specific sequence of amino acids, which then fold and interact to form functional proteins. Therefore, the correct answer is "Protein, proteins."
8.
RNA contains a 5-carbon sugar ring (pentose). It is the sugar found in RNA molecules. What is the name of this sugar? (Hint: please enter your answer in all lower case letters.)
Correct Answer
ribose
Explanation
RNA contains a 5-carbon sugar ring called ribose. Ribose is the sugar specifically found in RNA molecules.
9.
_____ is a nitrogenous base found in RNA in positions analogous to the thymine in DNA molecules. It is based upon a pyrimidine ring structure.
Correct Answer
E. Uracil
Explanation
Uracil is a nitrogenous base found in RNA in positions analogous to thymine in DNA molecules. It is based upon a pyrimidine ring structure. Unlike DNA, RNA does not contain thymine, instead, it contains uracil. Uracil pairs with adenine in RNA during transcription, forming a complementary base pair. It is one of the four bases that make up the genetic code in RNA, along with adenine, cytosine, and guanine.
10.
Transfer RNA is an adaptor molecule composed of RNA nucleotide bases. It is typically _____ to _____ nucleotides in length. It serves as the physical link between the nucleotide sequence of DNA, RNA, and amino acid sequence of proteins.
Correct Answer
B. 73 to 93
Explanation
Transfer RNA (tRNA) is a molecule that acts as an adapter between the nucleotide sequence of DNA or RNA and the amino acid sequence of proteins. It is composed of RNA nucleotide bases and is typically 73 to 93 nucleotides in length. This length allows tRNA to fold into a specific three-dimensional structure that enables it to recognize and bind to specific codons on mRNA and bring the corresponding amino acid to the growing protein chain during translation.
11.
Transcription; Step _____ initiates transcription of a gene by enabling binding of RNA polymerase to promoter DNA.
Correct Answer
A. One
Explanation
Step One initiates transcription of a gene by enabling binding of RNA polymerase to promoter DNA. This is because in transcription, the first step is the binding of RNA polymerase to the promoter region of the DNA. This binding is crucial for the initiation of transcription and the subsequent synthesis of RNA from the DNA template.
12.
Transcription; Step _____ helicase enzymes move a transcription bubble, which splits the double helix DNA molecule into two strands of unpaired DNA nucleotides.
Correct Answer
D. Two
Explanation
In transcription, helicase enzymes play a crucial role in unwinding the DNA double helix. They move along the DNA molecule, creating a transcription bubble by separating the two strands of DNA. This allows the RNA polymerase to access and transcribe the DNA template into RNA. Therefore, the correct step for helicase enzymes to create a transcription bubble and split the double helix DNA molecule into two strands of unpaired DNA nucleotides is step two.
13.
Transcription; Step _____ RNA polymerase adds matching RNA nucleotides that are paired with complementary DNA nucleotides of one DNA strand.
Correct Answer
E. Three
Explanation
RNA polymerase adds matching RNA nucleotides that are paired with complementary DNA nucleotides of one DNA strand. This process is known as transcription. In transcription, RNA polymerase moves along the DNA template strand and adds RNA nucleotides that are complementary to the DNA nucleotides. This results in the formation of a single-stranded RNA molecule that is complementary to the DNA template strand. Therefore, the correct step at which RNA polymerase adds matching RNA nucleotides is step three.
14.
Transcription; Step _____ RNA sugar-phosphate backbone forms with assistance from RNA polymerase to form an RNA strand.
Correct Answer
F. Four
Explanation
The RNA sugar-phosphate backbone forms with assistance from RNA polymerase to form an RNA strand. The process of transcription involves the synthesis of RNA using a DNA template. RNA polymerase catalyzes the formation of phosphodiester bonds between the sugar and phosphate groups of the RNA nucleotides, creating the sugar-phosphate backbone. This process occurs in a stepwise manner, with each nucleotide being added one at a time. Therefore, the correct step at which the RNA sugar-phosphate backbone forms is step four.
15.
Transcription; Step _____ Hydrogen bonds of the untwisted RNA + DNA helix break, freeing the newly synthesized RNA strand.
Correct Answer
A. Five
Explanation
In transcription, the process of synthesizing RNA from a DNA template, the hydrogen bonds between the RNA and DNA strands need to be broken in order to separate them. This allows the newly synthesized RNA strand to be released. The question is asking at which step this occurs. Since the correct answer is "Five," it suggests that at the fifth step of transcription, the hydrogen bonds of the untwisted RNA + DNA helix break, freeing the newly synthesized RNA strand.
16.
Transcription; Step _____ if the cell has a nucleus, the RNA is further processed and exits through to the cytoplasm through the nuclear pore complex.
Correct Answer
B. Six
Explanation
The correct answer is "Six". This step is referring to the processing of RNA in cells that have a nucleus. After the RNA is transcribed, it undergoes further processing before it can exit the nucleus and enter the cytoplasm. This processing includes modifications such as capping, splicing, and polyadenylation. Once the RNA has undergone these modifications, it can exit the nucleus through the nuclear pore complex and enter the cytoplasm, where it can carry out its functions.
17.
_____ _____ is a specific sequence of nucleotides that marks the end of a gene. (HINT: please enter your answers in all lower case letters.)
Correct Answer
termination signal
Explanation
A termination signal is a specific sequence of nucleotides that marks the end of a gene. It acts as a signal for the RNA polymerase to stop transcribing the gene and release the newly synthesized RNA molecule. This sequence helps in the proper termination of gene transcription and ensures that the correct length of RNA is produced.
18.
_____ _____ is the term for the rules that relate how a sequence of nitrogenous bases in nucleotides corresponds to a particular amino acid.
Correct Answer
A. Genetic code
Explanation
The term for the rules that relate how a sequence of nitrogenous bases in nucleotides corresponds to a particular amino acid is the genetic code. The genetic code is a set of rules that determines the translation of DNA or RNA sequences into proteins. It specifies which combinations of three nucleotides, called codons, correspond to specific amino acids or stop signals. This code is universal, meaning that it is shared by all living organisms.
19.
A codon is a series of three adjacent bases in one polynucleotide chain of a DNA or RNA molecule, which codes for a specific amino acid.
Correct Answer
A. True
Explanation
A codon is indeed a series of three adjacent bases in a DNA or RNA molecule that codes for a specific amino acid. This is a fundamental concept in genetics and is essential for the translation of genetic information into proteins. Each codon corresponds to a specific amino acid or a stop signal, allowing the correct sequence of amino acids to be assembled during protein synthesis. Therefore, the statement "A codon is a series of three adjacent bases in one polynucleotide chain of a DNA or RNA molecule, which codes for a specific amino acid" is true.
20.
What is the first codon of an mRNA that always codes for Methionine?
Correct Answer
A. Start codon
Explanation
The first codon of an mRNA that always codes for Methionine is the Start codon. The Start codon, which is AUG, signals the beginning of protein synthesis and also codes for Methionine. This codon is recognized by the ribosome and initiates the process of translation. Methionine is typically the first amino acid incorporated into a growing polypeptide chain during protein synthesis.
21.
In the genetic code, there are stop codons or termination codons. It is a nucleotide triplet that signals a termination of translation. Please select the correct "stop codon" as read in mRNA.
Correct Answer
C. UGA
Explanation
UGA is the correct stop codon in mRNA. Stop codons are nucleotide triplets that signal the end of protein synthesis during translation. When a ribosome encounters a stop codon, it releases the newly synthesized protein and disassembles from the mRNA strand. UGA is one of the three stop codons, along with UAA and UAG, that do not code for any amino acid. Instead, they act as signals for the ribosome to terminate translation.
22.
_____, _____, and _____ are stop codons in a nucleotide triplet. Please select the three correct codons from the list below.
Correct Answer(s)
A. UAA
B. UAG
C. UGA
Explanation
UAA, UAG, and UGA are stop codons in a nucleotide triplet. Stop codons are sequences of three nucleotides that signal the end of protein synthesis during translation. When a ribosome encounters a stop codon, it releases the newly synthesized protein and disassembles. UAA, UAG, and UGA are specifically recognized by release factors in the ribosome, leading to termination of protein synthesis. UUU, CCU, and UGC are not stop codons, but instead code for specific amino acids (phenylalanine, proline, and cysteine, respectively).
23.
_____ is a series of complex biochemical processes the nucleotides sequences in an organism's DNA are translated into the proteins. (Hint: please enter your answer(s) in all lower case letters.)
Correct Answer(s)
translation
Explanation
Translation is the process by which the nucleotide sequences in an organism's DNA are converted into proteins. It involves the decoding of the genetic information stored in DNA and the synthesis of proteins based on that information. During translation, messenger RNA (mRNA) molecules are produced from DNA templates and then used as templates for protein synthesis. Ribosomes, along with transfer RNA (tRNA) molecules, are responsible for reading the mRNA and assembling the correct sequence of amino acids to form a protein. This process is essential for the functioning and development of living organisms.
24.
When a small subunit of a ribosome charged with a tRNA+the amino acid methionine encounters an mRNA, it attaches and starts to scan for a start signal. Which translation step is being described?
Correct Answer
A. Initiation Step
Explanation
The given correct answer is "Initiation Step". This is because the explanation describes the process of a small subunit of a ribosome charged with a tRNA+the amino acid methionine attaching to an mRNA and scanning for a start signal. This process is specifically associated with the initiation step of translation, where the ribosome assembles and begins protein synthesis.
25.
When the ribosome reaches one of three stop codons. There are no corresponding tRNA's to that sequence. Which translation step is being described?
Correct Answer
C. Termination Step
Explanation
In the termination step of translation, the ribosome reaches one of the three stop codons (UAA, UAG, or UGA) on the mRNA. At this point, there are no corresponding tRNA molecules with anticodons that can bind to the stop codon. This leads to the release of the newly synthesized polypeptide chain from the ribosome and the dissociation of the ribosome from the mRNA. Therefore, the given correct answer, Termination Step, accurately describes this process.