Bio1334 Genetics - Molecular Genetics - DNA And Chromosomes (Lecture One)

Nucleotide - any member of a class of organic compounds in which the molecular structure comprises a nitrogen-containing unit (base) linked to a sugar and a phosphate group. The nucleotides are of great importance to living organisms, as they are the building blocks of nucleic acids, the substances that control all hereditary characteristics.

The correct answer is "Nucleoside, Nucleosides, A nucleoside." When sugar combines with a base, it forms a nucleoside. Nucleosides are organic compounds composed of a sugar molecule bonded to a nitrogenous base. They are important building blocks for nucleic acids, such as DNA and RNA. The combination of a sugar and a base in a nucleoside is crucial for the structure and function of these genetic materials.

The correct answer for this question is "Histone, Histones, A histone, Histone proteins, Histone protein, A histone protein". Histones are proteins that DNA wraps around in order to package the DNA. They play a crucial role in organizing and compacting DNA into a structure called chromatin, which allows for efficient storage and regulation of genetic information.

DNA is a right-handed double helix because its two strands twist around each other in a clockwise direction. This is supported by extensive scientific research and evidence. The right-handedness of DNA is due to the specific arrangement of its sugar-phosphate backbone and the pairing of nucleotide bases. This structural characteristic is fundamental to the stability and functionality of DNA as it allows for efficient replication and transcription processes.

Deoxyribose is a sugar molecule found in DNA, and thymine is one of the four nitrogenous bases present in DNA. When deoxyribose combines with thymine, it forms a nucleoside called thymidine. Thymidine is an essential component of DNA as it pairs with adenine during DNA replication and transcription, contributing to the accurate transmission of genetic information.

Deoxyribose is the five-carbon sugar component of DNA, where it alternates with phosphate groups to form the “backbone” of the DNA polymer and binds to nitrogenous bases. The presence of deoxyribose instead of ribose is one difference between DNA and RNA (ribonucleic acid). Deoxyribose was synthesized in 1935, but it was not isolated from DNA until 1954.

A genome refers to the complete set of genes present in an organism. It includes all the genetic material, including both coding and non-coding regions, that determines the characteristics and traits of an individual. The genome contains all the information necessary for the development, functioning, and reproduction of the organism. It is unique to each species and plays a crucial role in understanding the genetic basis of various biological processes and diseases.

When DNA wraps around the histone protein, the structure formed is called a nucleosome. The histone proteins act as spools around which the DNA is wound, forming a compact structure. This helps in packaging the DNA tightly and organizing it within the nucleus of the cell. The nucleosome is the basic unit of DNA packaging in eukaryotic cells and plays a crucial role in regulating gene expression and chromosome structure.

In a DNA double-helix, the 5' end of one strand is indeed opposite to the 3' end of another strand. This is due to the antiparallel nature of DNA strands, where one strand runs in the 5' to 3' direction and the other runs in the opposite direction. The 5' end of a DNA strand has a phosphate group attached to the 5' carbon of the sugar molecule, while the 3' end has a hydroxyl group attached to the 3' carbon. This arrangement allows for complementary base pairing between the strands, enabling DNA replication and protein synthesis.

Deoxyribose is a sugar molecule that is a component of DNA. Adenine is one of the four nitrogenous bases that make up DNA. When deoxyribose and adenine combine, they form deoxyadenosine, which is a nucleoside. Nucleosides are important building blocks of DNA and RNA. Deoxyadenosine consists of deoxyribose bonded to adenine, and it plays a crucial role in the structure and function of DNA.

Deoxyribose is a sugar molecule that is a component of DNA, while cytosine is one of the four nitrogenous bases found in DNA and RNA. When deoxyribose and cytosine combine, they form a nucleoside called cytidine. Cytidine consists of a deoxyribose sugar molecule bonded to a cytosine base. Nucleosides are important building blocks of nucleotides, which are the monomers of DNA and RNA.

Friedrich Miescher was the Scientist that isolated nucleic acid from human pus.
At a time when scientists were still debating the concept of "cell," Hoppe-Seyler and his lab were isolating the molecules that made up cells. Miescher was given the task of researching the composition of lymphoid cells — white blood cells.
These cells were difficult to extract from the lymph glands, but they were found in great quantities in the pus from infections. Miescher collected bandages from a nearby clinic and washed off the pus. He experimented and isolated a new molecule - nuclein - from the cell nucleus. He determined that nuclein was made up of hydrogen, oxygen, nitrogen and phosphorus and there was an unique ratio of phosphorus to nitrogen. He was able to isolate nuclein from other cells and later used salmon sperm (as opposed to pus) as a source.

When deoxyribose, a sugar molecule, combines with guanine, a nitrogenous base, they form a nucleoside called guanosine. Nucleosides are composed of a sugar molecule bonded to a nitrogenous base, and in this case, deoxyribose is bonded to guanine to create guanosine. This reaction is a key step in the synthesis of DNA molecules, as nucleosides are the building blocks of DNA. Therefore, when deoxyribose and guanine combine, they produce guanosine.

Nucleic acids can only be synthesized in vivo in the 5′-to-3′ direction.

Histone H1 is a protein that plays a crucial role in organizing DNA into a higher-order structure known as chromatin. It binds to the linker DNA between nucleosomes and helps to compact the nucleosomes together, forming a chromatin fiber. This chromatin fiber further condenses and folds to create a higher level of organization in the genome. Therefore, the correct answer is "Chromatin fiber." "Chromatin" alone refers to the DNA-protein complex, but it does not specifically describe the compaction and organization brought about by histone H1.

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DNA is a quaternary code because it has four possible bases. The term "quaternary" refers to a system or code that is based on four elements or components. In the case of DNA, the four bases are adenine (A), thymine (T), cytosine (C), and guanine (G). These bases form the building blocks of DNA and are combined in different sequences to encode genetic information. Therefore, DNA can be described as a quaternary code due to its reliance on four possible bases.

After chromatin fiber is formed by the Histone H1 protein, chromatin is further condensed by scaffold proteins. These proteins play a crucial role in organizing and compacting the chromatin structure. They provide a structural framework for the chromatin, allowing it to be tightly packaged and organized into higher-order structures. This condensation helps to regulate gene expression and ensure the stability of the genome.

The answer "This one!" is correct because it implies that the image being referred to shows a right-handed double helix. The other options do not provide any specific information or context, so they cannot be determined as correct.

The correct answer is that Adenine and guanine are purines, while cytosine and thymine are pyrimidines. This statement is correct because purines and pyrimidines are two types of nitrogenous bases found in DNA and RNA. Adenine and guanine are purines because they have a double-ring structure, while cytosine and thymine are pyrimidines because they have a single-ring structure. This is a fundamental concept in molecular biology and genetics, and understanding the structure and composition of DNA and RNA is crucial in understanding their functions and roles in genetic information storage and transmission.

Histone protein H1 is known as a linker protein. Histones are proteins that help organize and package DNA into a structure called chromatin. H1 is a specific type of histone protein that binds to the DNA between nucleosomes, which are the basic units of chromatin. This binding helps to stabilize the structure of chromatin and regulate gene expression. Therefore, H1 acts as a linker between nucleosomes, earning its name as a linker protein.

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The complementary strand of a DNA sequence is formed by pairing each base with its complementary base. In this case, the given sequence is 5'-TGGTCGGAATT-3'. To find its complementary strand, we need to pair each base with its complementary base. A pairs with T, T pairs with A, G pairs with C, and C pairs with G. Therefore, the complementary strand of 5'-TGGTCGGAATT-3' is 5'-AATTCCGACCA-3'.

FALSE.
The names of the four core histone proteins are H2A, H2B, H3 and H4.

Every human cell contains 6 x 10^9 base pairs. This is because the human genome consists of approximately 3 billion base pairs, and each cell in the body contains a complete set of DNA, which includes the entire genome. Therefore, the correct answer is 6 x 10^9 base pairs.

Rosalind Franklin concluded about the structure of DNA:
- The structure was double helical
- Phosphate groups laid on the outside of the molecule
- The helix was 20 nanometers in diameter