Chapter 12 Biology CCA Practice Test

Franklin is the correct answer because she was the scientist who took the x-ray diffraction picture that provided crucial evidence for the structure of DNA. Her work, along with that of Watson and Crick, was instrumental in the discovery of the double helix structure of DNA.

Griffith discovered a transforming principle. This refers to Frederick Griffith, a British bacteriologist who conducted an experiment in 1928 known as the Griffith's experiment. In his experiment, Griffith observed that a non-virulent strain of bacteria could become virulent when it was exposed to heat-killed virulent bacteria. This led to the discovery of a "transforming principle" that could transfer genetic information between bacteria, later identified as DNA. This groundbreaking discovery laid the foundation for the field of molecular genetics and our understanding of genetic transformation.

Watson and Crick used Rosalind Franklin's x-ray diffraction data to propose the double helix structure of DNA. This indicates that Watson and Crick relied on Franklin's experimental findings to develop their model of DNA's structure.

The chemical composition of DNA includes four nitrogenous bases: adenine (A), thymine (T), guanine (G), and cytosine (C). These bases pair up in a specific manner, with adenine always pairing with thymine and guanine always pairing with cytosine. This pairing is crucial for the structure and function of DNA. Therefore, the statement that the chemical composition of DNA includes adenine, thymine, guanine, and cytosine is true.

Nucleotides are the fundamental structural units of nucleic acids. They are composed of a phosphate group, a sugar molecule, and a nitrogenous base. Nucleotides are the building blocks of DNA and RNA molecules. They form long chains through phosphodiester bonds between the sugar and phosphate groups, with the nitrogenous bases projecting from the sugar-phosphate backbone. Nucleotides play a crucial role in storing and transmitting genetic information, as well as participating in various cellular processes such as energy transfer and enzyme reactions.

not-available-via-ai

Hershey and Chase conducted a series of experiments that provided evidence supporting the idea that DNA is the genetic material. In their famous experiment, they used bacteriophages (viruses that infect bacteria) to infect bacterial cells. They labeled the DNA of the bacteriophage with radioactive phosphorus and the protein coat with radioactive sulfur. After infecting the bacteria, they found that the radioactive phosphorus (DNA) was transferred into the bacterial cells, while the radioactive sulfur (protein) remained outside. This indicated that DNA, not protein, was responsible for carrying genetic information, confirming that DNA is the genetic material.

A series of three bases is called a codon. Codons are found in DNA and RNA molecules and they represent specific instructions for the synthesis of proteins. Each codon codes for a particular amino acid or a start/stop signal. The sequence of codons determines the sequence of amino acids in a protein, thus playing a crucial role in protein synthesis.

RNA is single stranded because it is composed of a single strand of nucleotides. Unlike DNA, which is double stranded, RNA does not have a complementary strand. This single-stranded structure allows RNA to fold into complex shapes and perform various functions within the cell, such as protein synthesis and gene regulation. The single-stranded nature of RNA also makes it more versatile and adaptable compared to DNA, as it can form different secondary structures and interact with other molecules more easily.

Pauling is the correct answer because Linus Pauling, an American chemist, was the one who discovered that proteins often take the shape of an alpha helix, spiraling like a coil spring. His groundbreaking work in the field of molecular biology and his discovery of the secondary structure of proteins earned him the Nobel Prize in Chemistry in 1954.

Wilkins is the correct answer because he shared Rosalind Franklin's x-ray diffraction with Watson without her permission. This implies that Wilkins acted unethically by disclosing Franklin's work without obtaining her consent, which violated her intellectual property rights and undermined her contribution to the discovery of the structure of DNA. This breach of trust and professional conduct had significant implications for Franklin's recognition and the subsequent Nobel Prize awarded to Watson, Crick, and Wilkins.

RNA carries instructions for protein synthesis. This is because RNA molecules are transcribed from DNA and carry the genetic information from the DNA to the ribosomes, where proteins are synthesized. The process of protein synthesis involves the translation of the instructions encoded in the RNA molecules into the sequence of amino acids that make up proteins. Therefore, RNA plays a crucial role in the synthesis of proteins in cells.

occurs in nucleus

The components of the nucleic acid monomer are sugar, base, and phosphate. The sugar component provides the backbone of the nucleic acid molecule, the base component determines the genetic code, and the phosphate component links the sugar and base together. Therefore, all of the above options are correct.

Miescher is the correct answer because he was the scientist who isolated DNA from fish sperm and the pus of open wounds and named it nuclein. This discovery was a significant contribution to the understanding of genetic material and laid the foundation for future research on DNA.

Albinism is a genetic condition characterized by the lack of pigmentation in the skin, hair, and eyes. It is caused by a defect in the production of melanin, the pigment responsible for giving color to these body parts. People with albinism have very light or white skin, hair, and eye color, and they are often sensitive to sunlight. This condition can also affect the development of the eyes, leading to vision problems. Tay-Sachs, phenylketonuria, and Huntington's are unrelated genetic disorders and do not specifically involve lack of pigmentation.

The complement of AUG in RNA is UAC. In RNA, adenine (A) pairs with uracil (U), and guanine (G) pairs with cytosine (C). Therefore, the complement of A is U, the complement of U is A, and the complement of G is C. Since AUG is the start codon in RNA, its complement would be UAC.

Sickle cell anemia is the correct answer because it is a genetic disorder that causes red blood cells to become sickle-shaped, rigid, and prone to breaking down. This abnormal shape makes it difficult for the cells to pass through small blood vessels, leading to blockages and reduced oxygen delivery to tissues. The collapse of red blood cells is a characteristic feature of sickle cell anemia. Muscular dystrophy and polydactyl are unrelated conditions that do not involve the collapse of red blood cells.

Chromosomes are coiled strands of nucleic acids that contain genetic information. They are found in the nucleus of cells and are made up of DNA and proteins. Chromosomes play a crucial role in carrying and transmitting genetic information from one generation to the next. They are responsible for determining an individual's traits and characteristics.

Proteins are polymers made up of repeating units called amino acids. Amino acids are the monomers of proteins. They are organic compounds that contain an amino group (-NH2) and a carboxyl group (-COOH) attached to a central carbon atom. The side chain, or R-group, varies among different amino acids, giving each amino acid its unique properties. When amino acids join together through peptide bonds, they form long chains called polypeptides, which fold into specific three-dimensional structures to create proteins. Therefore, amino acids are the monomers that make up proteins.

replication

Nucleosomes are the basic, beadlike units of DNA packaging in eukaryotes. They consist of a segment of DNA wound around a protein core. This packaging helps to condense the DNA and allows for efficient storage and organization within the cell. Nucleosomes play a crucial role in regulating gene expression and controlling access to the DNA for processes such as transcription and replication.

Autosomes are chromosomes that are not involved in determining the sex of an individual. In humans, there are 23 pairs of chromosomes, with one pair being the sex chromosomes (X and Y) and the remaining 22 pairs being autosomes. Therefore, the correct answer is 22, as there are 22 autosomes out of the total 23 chromosomes.

Nucleic acids are composed of repeating units called nucleotides. These nucleotides consist of three components: a nitrogenous base, a sugar molecule, and a phosphate group. The nitrogenous base can be adenine, guanine, cytosine, or thymine (in DNA) or uracil (in RNA). The sugar molecule is either deoxyribose (in DNA) or ribose (in RNA). The phosphate group is responsible for linking the nucleotides together to form the nucleic acid strand. Therefore, the correct answer is nucleotides.

Tay-Sachs is a genetic disorder that is inherited in an autosomal recessive manner. This means that both parents must carry a copy of the mutated gene for the disorder to be passed on to their child. The disorder leads to the degeneration of the nervous system, causing a decline in cognitive and motor functions. Symptoms usually appear in infancy and progress over time, leading to severe disability and a shortened lifespan.