DNA, RNA, & Protein Synthesis Test B

Crick and Watson's discovery revealed that DNA molecules have a double helix structure. This means that the DNA molecule consists of two strands that are twisted around each other in a spiral shape, resembling a twisted ladder. The double helix structure is crucial for DNA's ability to store and transmit genetic information.

Griffith's discovery that a harmless strain of Streptococcus pneumoniae could become virulent after exposure to heat-killed virulent strains is known as transformation. This process involves the transfer of genetic material from one bacterium to another, resulting in the acquisition of new traits.

A pathogen is any organism that is capable of causing disease or a toxic response in another organism. It can be a bacterium, virus, fungus, parasite, or any other microorganism. Pathogens invade the body and disrupt normal bodily functions, leading to illness or infection. They can be transmitted through various means such as direct contact, airborne droplets, contaminated food or water, or vectors like mosquitoes or ticks. Understanding pathogens and their mechanisms of infection is crucial for preventing and treating diseases.

DNA replication is the process by which DNA is copied in a cell before mitosis, meiosis, or binary fission. During DNA replication, the double-stranded DNA molecule unwinds and separates into two strands. Each strand serves as a template for the synthesis of a new complementary strand, resulting in two identical DNA molecules. This process ensures that each daughter cell receives an exact copy of the parent cell's DNA during cell division.

According to base-pairing for DNA, adenine pairs with thymine and guanine pairs with cytosine. This is based on the complementary base pairing rule in DNA, where adenine always pairs with thymine through two hydrogen bonds, and guanine always pairs with cytosine through three hydrogen bonds. This pairing is essential for DNA replication and maintaining the genetic code.

In DNA, cytosine on one strand pairs with guanine on the opposite strand, and adenine pairs with thymine. This is known as base-pairing rules, where specific nitrogenous bases form complementary pairs with each other. The bases always pair in a specific way, with cytosine always pairing with guanine and adenine always pairing with thymine. These base-pairing rules are fundamental to the structure and function of DNA.

Escherichia coli is a gram-negative, rod-shaped bacterium that is commonly found in the intestinal tract of animals, as well as in soil and water. It is known for its role in various biological processes and has been extensively studied in scientific research. Escherichia coli was also the first organism to be used for cloning and propagating genes of other species, making it a crucial tool in genetic engineering and biotechnology.

DNA Ligase is a specific type of enzyme that plays a crucial role in DNA replication and repair. It catalyzes the formation of a phosphodiester bond between the sugar-phosphate backbone of DNA strands, joining them together. The correct answer, "DNA Ligase, DNA ligase," indicates that DNA Ligase is the enzyme responsible for this process. The repetition of the term emphasizes its importance and specificity in DNA strand joining.

mRNA, or messenger RNA, is a type of RNA molecule that carries genetic information from DNA to the ribosome. It serves as a template for protein synthesis by providing the instructions for assembling amino acids in the correct order. Unlike other types of RNA, mRNA is single-stranded and can be translated into proteins by the ribosome. Therefore, mRNA is the correct answer for this question.

A virus that infects bacteria is called a bacteriophage. Bacteriophages are composed of genetic material (DNA or RNA) enclosed in a protein coat. When a bacteriophage infects a bacterium, it injects its genetic material into the host cell. The viral genome then takes control of the bacterium's metabolism, forcing it to produce more copies of the virus. Eventually, the bacterium bursts, releasing the newly formed bacteriophages to infect other bacteria.

During DNA replication, the two strands of the double helix separate to allow for the synthesis of new DNA strands. This separation occurs at specific regions known as replication forks. At the replication forks, helicases unwind the DNA strands, creating a Y-shaped structure where the DNA is being replicated. Therefore, the correct answer is replication forks.

The given mRNA sequence CUC-AAG-UGC-UUC translates to Leu - Lys - Cys - Phe. Each codon in the mRNA sequence corresponds to a specific amino acid, and when translated, the sequence of amino acids is Leu - Lys - Cys - Phe.

Frederick Griffith was a British bacteriologist who specialized in studying the epidemiology and pathology of bacterial pneumonia.

The two strands of DNA are said to be complementary to each other because they have a specific pairing of nitrogenous bases. Adenine always pairs with thymine, and cytosine always pairs with guanine. This complementary base pairing allows the DNA strands to bond together and form a stable double helix structure.

Thymine is also known as 5-methyluracil, a pyrimidine nucleobase.

The statement is false because in transcription, the hydrogen bonds between the RNA and DNA strands do not break. Instead, the RNA polymerase enzyme separates the DNA strands, allowing the RNA polymerase to synthesize the RNA strand using one of the DNA strands as a template. The hydrogen bonds between the DNA strands remain intact throughout the process.

Frederick Griffith studied the transfer of genetic material from one cell to another, which is known as transformation. This process involves the uptake and incorporation of foreign DNA into a recipient cell, leading to a change in its genetic makeup. Transduction refers to the transfer of genetic material through a virus, transportation is not a term used in this context, recombination involves the rearrangement of genetic material, and genetic transfer is a general term that can encompass various mechanisms including transformation.

DNA replication occurs before cell division because during cell division, the DNA needs to be duplicated so that each new cell receives a complete set of genetic information. This process ensures that the genetic material is accurately passed on to the daughter cells. The S phase of the cell cycle is specifically dedicated to DNA replication, where the DNA is unwound and new strands are synthesized. Therefore, DNA replication is a crucial step that occurs before cell division.

Step 1 is the correct answer because it is the initial step in the process of initiating transcription. It involves the binding of RNA polymerase to the promoter DNA, which is necessary for the transcription of the gene to begin.

The correct answer is GAG TTC ACG AAG. This is because the process of transcription involves the synthesis of mRNA from a DNA template. During transcription, the DNA strand is used as a template to create a complementary mRNA strand. In RNA, the base thymine (T) is replaced by uracil (U). Therefore, the mRNA strand would have the sequence GAG TTC ACG AAG, which is the same as the given answer.

Replication forks, which are the points where DNA strands separate and new strands are synthesized, play a crucial role in DNA replication. They actually speed up the replication process by allowing the simultaneous synthesis of new DNA strands in both directions. This means that replication can occur at a faster rate, enabling the efficient and timely duplication of the entire DNA molecule. Therefore, the presence of replication forks enhances the speed of the replication process.

Avery is the correct answer because his research team used a protease enzyme to destroy proteins, RNase to destroy RNA, and DNase to destroy DNA.

At the end of replication, each new DNA molecule is composed of a new strand and an original strand of DNA. This is because DNA replication is a semi-conservative process, where each of the two resulting DNA molecules contains one original strand and one newly synthesized complementary strand. This ensures that the genetic information is faithfully passed on to the daughter cells during cell division.

DNA polymerases are enzymes that are responsible for synthesizing new DNA strands during replication. They have a proofreading function, which means they can detect and correct errors that occur during DNA replication. This proofreading activity helps to maintain the accuracy of the DNA sequence. Therefore, DNA polymerases are the correct answer as they proofread the new DNA molecule during replication.

In DNA replication, the two original strands of DNA first separate, creating a replication fork. Then, DNA polymerase adds nucleotides to each DNA strand, creating two new DNA molecules. Therefore, the formation of two new DNA molecules happens last in replication.

The statement is false because the human genome actually contains 46 chromosomes, not 23. Each human cell typically contains two sets of 23 chromosomes, one set inherited from each parent. Additionally, while it is true that the human genome contains approximately 3.2 billion base pairs, the number of genes is estimated to be around 20,000-25,000, not 200,000.

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Step 3 is the correct step because it states that RNA polymerase adds matching RNA nucleotides that are paired with complementary DNA nucleotides of one DNA strand. This step is crucial in the process of transcription, where DNA is used as a template to synthesize RNA. RNA polymerase recognizes the DNA sequence and adds RNA nucleotides that are complementary to the DNA template strand, resulting in the formation of an RNA molecule.

RNA polymerase assists in the formation of the RNA sugar-phosphate backbone during transcription. This process involves the addition of nucleotides to the growing RNA strand, with the sugar and phosphate groups linking together to form the backbone. Step 4 is the correct answer as it suggests that the formation of the RNA sugar-phosphate backbone occurs at this step.

During translation, the process of protein synthesis, different types of RNA molecules are involved. Transfer RNA (tRNA) is responsible for bringing amino acids to the ribosome, where protein synthesis occurs. Messenger RNA (mRNA) carries the genetic information from DNA to the ribosome, serving as a template for protein synthesis. Ribosomal RNA (rRNA) is a component of the ribosome itself, where it helps in the assembly of amino acids into proteins. Therefore, the correct answer is tRNA, mRNA, mRNA, rRNA.