Cell Biology Chapter 11

Translation is the process by which the genetic information encoded in RNA molecules is used to synthesize proteins. During translation, the sequence of nucleotides in the RNA is converted into a sequence of amino acids, which are the building blocks of proteins. This process occurs in the ribosomes, where transfer RNA molecules bring the corresponding amino acids to the growing polypeptide chain based on the codons present in the RNA. Therefore, the given correct answer, "Translation," accurately describes the process of converting RNA into amino acids.

The process of DNA to RNA is called transcription. During transcription, the DNA sequence is used as a template to synthesize a complementary RNA molecule. This process occurs in the nucleus of the cell and is catalyzed by an enzyme called RNA polymerase. Transcription is an essential step in gene expression, as it allows the genetic information encoded in DNA to be transcribed into RNA, which can then be translated into proteins.

Bacterial chromosome replication is circular because bacteria have a single, circular chromosome that replicates in a circular manner. This is in contrast to eukaryotic organisms, which have linear chromosomes that replicate in a linear manner. Plantae is not a type of chromosome replication, but rather a kingdom of organisms that includes plants.

The given statement is true. If one nucleotide is 0.34 nm, then the distance for one complete turn of the helix can be calculated by multiplying the length of one nucleotide by the total number of nucleotides in a turn. In this case, the total number of nucleotides in a turn is 10 (since 0.34 nm x 10 = 3.4 nm), which means that one complete turn of the helix is 3.4 nm. Therefore, the statement is true.

DNA polymerase I is responsible for removing RNA primers during DNA replication and filling in the gaps with DNA nucleotides. It has a 5' to 3' exonuclease activity that allows it to remove the RNA primer, and a 5' to 3' polymerase activity that allows it to synthesize DNA in the gap left by the primer removal. This process is known as primer removal and gap filling, and DNA polymerase I is the enzyme that performs this task.

Watson and Crick discovered the sugar-phosphate backbone with nitrogenous bases and hydrogen bonds. They are famous for their groundbreaking work in determining the structure of DNA, which they published in 1953. Their model, known as the double helix, described how the sugar-phosphate backbone holds the nitrogenous bases together through hydrogen bonds. This discovery revolutionized our understanding of genetics and laid the foundation for modern molecular biology.

Eukaryotic chromosome replication forms bubbles where the replication takes place. During replication, the double-stranded DNA unwinds and forms a replication fork. As the replication fork moves along the DNA, new strands are synthesized in both directions. This process creates bubbles, also known as replication bubbles, where the DNA strands separate and replication occurs. In eukaryotic cells, replication bubbles are formed at multiple origins of replication along the chromosome, allowing for efficient and simultaneous replication of the entire genome.

Initiation is the correct answer because it refers to the process in transcription where RNA polymerase binds to the DNA template strand at the promoter region. This binding is facilitated by the recognition site for the sigma factor, which helps in the initiation of transcription. Therefore, initiation is the step that starts everything in transcription and involves the recognition site for the sigma factor.

Avery, MacLeod, and McCarty are all scientists who conducted the famous Avery-MacLeod-McCarty experiment in 1944. This experiment demonstrated that DNA is the genetic material responsible for transmitting hereditary information. Through a series of experiments, they showed that DNA could transform harmless bacteria into pathogenic bacteria, proving that DNA carries the genetic instructions. Therefore, the correct answer is A, B, and C, as all three scientists contributed to the discovery that DNA is the genetic material.

C, T, and U are single rings and are called pyrimidines. Pyrimidines are a type of nitrogenous base found in nucleotides, which are the building blocks of DNA and RNA. They consist of a single carbon-nitrogen ring structure. Cytosine (C), thymine (T), and uracil (U) are all examples of pyrimidines. These bases play a crucial role in the genetic code, as they pair with specific bases (guanine for cytosine, adenine for thymine or uracil) to form the rungs of the DNA or RNA double helix.

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A and G have double rings in their chemical structure, which classifies them as purines. Purines are one of the two types of nitrogenous bases found in DNA and RNA, along with pyrimidines. The presence of double rings in purines plays a crucial role in the stability and function of nucleic acids.

Polymerase goes from the 5' end to the 3' end during DNA replication and transcription. This means that it adds nucleotides to the growing DNA or RNA strand in the 5' to 3' direction. The 5' to 3' refers to the orientation of the carbon atoms in the sugar-phosphate backbone of the nucleic acid molecule. The 5 to 3 answer is not clear and does not provide the necessary information about the directionality of polymerase.

Hershey and Chase's experiment involved the use of bacteriophages (phages) to determine whether DNA or protein is the genetic material that is passed on during viral infection. They labeled the DNA of the phages with radioactive phosphorus and the protein coat with radioactive sulfur. By observing which radioactive material was found inside the infected bacteria, they concluded that DNA, not protein, is the genetic material.

The correct answer is 20. This is because when you have a percentage, you can convert it to a decimal by dividing it by 100. In this case, 30% would be 0.30. To find what percent T is of G, you would multiply G by 0.30. Therefore, 30% G is equal to 0.30G. To find what percent T is of G, you would divide 0.30G by G, which simplifies to 0.30. Multiplying 0.30 by 100 gives you 30, so T is 30% of G. Therefore, if 30% G is 30%, then 30% G is equal to 20% T.

In the conservative mechanism of DNA replication, the original DNA molecule remains intact and serves as a template for the synthesis of two new DNA molecules. This means that both parent strands are conserved and used as templates for the synthesis of two new strands. Therefore, in conservative replication, two parent strands and two newly made strands are produced.

In the beginning, proteins were thought to carry genetic information. This belief was based on the fact that proteins are present in large quantities within cells and they exhibit diverse functions. However, further research and experiments led to the discovery that DNA, not proteins, carries the genetic information. DNA was found to be the molecule responsible for transmitting genetic instructions and determining the traits of living organisms. This discovery revolutionized the field of genetics and our understanding of inheritance.

Primase is an enzyme that synthesizes short RNA primers during DNA replication. These primers provide a starting point for DNA polymerase to begin synthesizing new DNA strands. Therefore, the correct answer is "Primer," as primase is responsible for creating the primer molecules needed for DNA replication.

DNA polymerase III is responsible for the majority of DNA replication in bacteria. This enzyme is highly processive and has a high fidelity, allowing it to efficiently and accurately replicate the entire bacterial genome. DNA polymerase I is involved in DNA repair and removal of RNA primers during replication, while DNA polymerases II, IV, and V are mainly involved in DNA repair mechanisms. Therefore, DNA polymerase III is the main enzyme responsible for the actual synthesis of new DNA strands during replication in bacteria.

Helicase is an enzyme that plays a crucial role in DNA replication. It unwinds and separates the double-stranded DNA molecule by breaking the hydrogen bonds between the base pairs. This process is often referred to as "unzipping" or "unzipping the DNA." Therefore, the correct answer is "unzips" or "unzip."

Ligase is an enzyme that plays a crucial role in DNA replication and repair. It is responsible for joining or "gluing" DNA fragments together by catalyzing the formation of phosphodiester bonds between adjacent nucleotides. This process is essential for the completion of DNA replication, as well as for repairing damaged DNA strands. Therefore, the correct answer is "glue fragments" and "bind fragments," as ligase functions to connect separate DNA fragments into a continuous strand.

In the semiconservative mechanism of DNA replication, the original DNA molecule serves as a template for the synthesis of two new DNA molecules. Each new DNA molecule consists of one parent strand, which is the original template strand, and one newly made strand. This means that one parent strand is conserved in each new DNA molecule, while one newly made strand is added during replication. Therefore, the correct answer is 1 parent and 1 newly made strand, or 1 and 1.

Griffith's experiment, known as Bacterial Transformations or Transformation Principle, demonstrated that genetic material can be transferred between bacterial strains. In his experiment, he observed that when a Rough strain (non-virulent) and a Smooth strain (virulent) of bacteria were mixed together, the Rough strain transformed into the Smooth strain, acquiring the ability to cause disease. This discovery played a crucial role in understanding the transfer of genetic information and laid the foundation for further research in genetics and molecular biology.

The correct answer is A-30.3 T-30.3 G-19.5 C-19.9. This answer is correct because it follows Erwin Chargoff's rule, which states that in DNA, the amount of adenine (A) is equal to the amount of thymine (T), and the amount of guanine (G) is equal to the amount of cytosine (C). Therefore, the percentages of A and T should be the same, and the percentages of G and C should be the same. This answer choice reflects that pattern, with A and T both at 30.3% and G and C both at 19.5% and 19.9%.

In translation, a sequence is started and stopped by codones. Codones are specific sequences of three nucleotides in mRNA that code for a specific amino acid or signal the end of protein synthesis. These codones act as the "start" and "stop" signals for the ribosome during translation, determining the beginning and end of a protein-coding sequence.

Dispersive replication is a type of mechanism for DNA replication where segments of new DNA are interspersed with the parental DNA. In this process, the parental DNA strands break into smaller fragments, and each fragment serves as a template for the synthesis of a complementary DNA strand. The resulting DNA strands have segments of new DNA interspersed with segments of the original parental DNA, creating a mixed or "dispersed" pattern. This mechanism was proposed by Matthew Meselson and Franklin Stahl in 1958 based on their experiments with isotopes of nitrogen.

Topoisomerase is an enzyme that plays a crucial role in DNA replication and transcription by managing the tension that arises when the DNA double helix is unwound. It is responsible for both stopping and relieving tension in the DNA molecule. By stopping tension, topoisomerase prevents the DNA strands from becoming overly twisted or tangled. On the other hand, it also relieves tension by unwinding the DNA and allowing it to relax. In summary, topoisomerase regulates the level of tension in the DNA molecule to ensure proper replication and transcription processes.

Binding proteins play a crucial role in preventing the binding or reassociation of molecules or strands that have been separated. They act as inhibitors, stopping the molecules or strands from coming together again. This prevents the formation of unwanted interactions and ensures that the molecules or strands remain separate and functional.

The correct answer is "Phosphates and Sugars". The backbone of the helix in DNA consists of alternating phosphate groups and sugar molecules. The phosphate groups provide a negative charge, while the sugar molecules provide a structural support for the DNA molecule. This alternating pattern of phosphates and sugars forms the backbone of the DNA helix. Therefore, the correct answer includes all variations of these two components.

The splicozome is responsible for breaking the 5'cap.

When DNA polymerase identifies a mismatched nucleotide and removes it from the daughter strand, this process is known as proofreading. Proofreading is an essential mechanism in DNA replication that helps maintain the accuracy of the genetic code. It allows DNA polymerase to detect and correct errors in the newly synthesized DNA strand by removing the incorrect nucleotide and replacing it with the correct one. This ensures the fidelity of DNA replication and reduces the occurrence of mutations.

The correct answer is Gamma because DNA polymerase gamma is the enzyme responsible for the replication of mitochondrial DNA in humans. This enzyme is specifically designed for the replication of mitochondrial DNA and is not involved in nuclear DNA replication. It plays a crucial role in maintaining the integrity and function of the mitochondria, which are essential for energy production in cells.

Maselson and Stahl did not discover that DNA replication always goes from 5' to 3'. This statement is incorrect. The correct answer is not available.

Polymerase is an enzyme that plays a crucial role in DNA replication. It is responsible for synthesizing new strands of DNA by adding complementary nucleotides to the existing template strand. This process is essential for the accurate replication of genetic information during cell division. Therefore, the correct answer is "synthesizes DNA." The other options, "synthesizes" and "synthesize," are not specific to DNA and do not accurately describe the function of polymerase.

The linkage in DNA and RNA strands is called a phosphodiester bond. This bond is formed between the phosphate group of one nucleotide and the sugar molecule of the adjacent nucleotide in the DNA or RNA strand. It plays a crucial role in connecting the nucleotides together, forming the backbone of the DNA and RNA molecules. The phosphodiester bond provides stability and strength to the DNA and RNA strands, allowing them to carry and transmit genetic information accurately.

DNA polymerase is responsible for covalently linking nucleotides together to form DNA strands. DNA polymerase is an enzyme that catalyzes the formation of phosphodiester bonds between adjacent nucleotides during DNA replication. It adds nucleotides to the growing DNA strand according to the complementary base pairing rule. This process ensures the accurate replication of the DNA molecule and the maintenance of its genetic information.