Unit Two Chapter One 3rd SEC. Quiz 2

The structural non-histones play a role in regulating the spatial organization of the DNA. This means that they help in organizing and arranging the DNA molecule in the nucleus of the cell. They ensure that the DNA is properly folded and packaged, allowing for efficient gene expression and DNA replication. This organization is crucial for the proper functioning of the cell and the maintenance of its genetic information.

The letter X on the diagram indicates the chromatin. Chromatin is the material that makes up chromosomes, consisting of DNA and proteins. It is in a less condensed form compared to chromosomes and is found in the nucleus of a cell during interphase.

Inversion mutation refers to a genetic change where segments of DNA are released from a chromosome and then re-inserted in the opposite orientation. This results in the rearrangement of genetic material within a chromosome.

Diagram 2 shows a substitution mutation because it depicts a single nucleotide being replaced by another nucleotide. In this type of mutation, one base pair is substituted for another, resulting in a change in the DNA sequence. This can lead to the production of a different protein or a non-functional protein. Diagram 1 and 3 do not show substitution mutations as they represent other types of mutations such as insertion or deletion of nucleotides. Therefore, the correct diagram that demonstrates a substitution mutation is diagram 2.

DNA is highly condensed and wrapped around nuclear proteins to form a condensed chromatin. These nuclear proteins are called histones, which help in packaging the DNA tightly. However, in addition to histones, there are also non-histone proteins that contribute to the structural organization of chromatin. These non-histone proteins are involved in various functions such as DNA replication, repair, and transcription regulation. Therefore, the correct answer is structural non histones, as they play a role in the compact and organized structure of chromatin along with histones.

Arginine and lysine amino acids have positive (R) groups and are basic amino acids. They also share in building up histone molecules. However, they do not have the same (R) groups, as the (R) group of arginine contains a guanidino group while the (R) group of lysine contains an amino group.

The given mutation involves the addition of the nucleotide sequence "GCAT" into the original sequence "ATC CAT". This results in a longer sequence compared to the original, indicating an insertion mutation.

Triploidy in humans refers to the condition where an individual has three sets of chromosomes instead of the usual two. This chromosomal abnormality often leads to severe developmental issues and is commonly associated with miscarriages. The presence of an extra set of chromosomes disrupts the normal development of the fetus, resulting in miscarriage. Therefore, triploidy in humans is known to cause miscarriages rather than congenital deformities, sterility, or death at puberty.

The correct answer is "Condensed chromatin – coiled nucleosomes – nucleosomes – histones." In eukaryotes, DNA is tightly packaged into structures called nucleosomes, which consist of DNA wrapped around histone proteins. Nucleosomes then coil further to form condensed chromatin, which is the highly compacted form of DNA. Therefore, (A) condensed chromatin comes first, followed by (B) coiled nucleosomes, (C) nucleosomes, and (D) histones.

Gene mutation refers to the mutation that leads to a change in the arrangement of the nitrogenous bases of the DNA molecule. This type of mutation can occur at the level of a single gene and can result in the production of a different protein or the absence of a protein altogether. It can be caused by various factors such as errors during DNA replication, exposure to certain chemicals or radiation, or spontaneous changes in the DNA sequence. Chromosomal number mutation refers to changes in the number of chromosomes, while chromosomal structure mutation refers to changes in the structure of chromosomes.

Plasmids are small circular DNA molecules found in bacteria. They are separate from the bacterial chromosome and can replicate independently. Plasmids often carry genes that provide advantages to the bacteria, such as antibiotic resistance or the ability to produce certain proteins. They can also transfer between bacteria, allowing for the spread of these advantageous genes. The other options, double helix, chromatin, and sugar-phosphate backbone, are all components or structures related to DNA, but they do not specifically refer to the small circular DNA found in bacteria.

Eukaryotic DNA is double helix in structure, but its ends are not joined to each other. Instead, they are free and can be replicated or transcribed independently. This is in contrast to prokaryotic DNA, where the ends are joined to form a circular structure. The other characteristics listed, such as being linked with histones or non-histones proteins and the need to be tightly packed to fit into the nucleus, are all true for eukaryotic DNA.

Yeast is a type of eukaryote that contains plasmid. Plasmids are small, circular DNA molecules that can be found in some eukaryotic cells, including certain types of yeast. Plasmids are separate from the cell's main genome and can replicate independently. Yeast is known for its ability to ferment sugars and produce alcohol, which is made possible by the presence of plasmids. Therefore, yeast is the correct answer in this case.

DNA is not organized in the form of chromosomes in bacteria, chloroplasts, and mitochondria. In bacteria, the DNA is usually present in a circular form called a plasmid, which is separate from the main chromosome. In chloroplasts and mitochondria, the DNA is also organized differently from the linear chromosomes found in the nucleus of eukaryotic cells. Instead, it is organized in circular or linear molecules, and the number of DNA molecules can vary within these organelles. Therefore, the correct answer is that DNA is not organized in the form of chromosomes in all of the above options.

During cell division, chromatin undergoes a process called condensation, where it becomes tightly coiled and compacted. This condensation allows for easier separation and distribution of genetic material into daughter cells. Therefore, chromatin will condense to form visible chromosomes as cells prepare for cell division.

not-available-via-ai

Bacterial DNA molecules do not contain free phosphate groups. The phosphate groups in DNA are covalently bonded to the deoxyribose sugar molecules, forming the backbone of the DNA strand. Therefore, the correct answer is zero.

If the DNA double helix in a somatic cell was unwound, its length would be about 200 cm. This is because the DNA double helix consists of two strands that are tightly coiled around each other, forming a twisted ladder shape. When the helix is unwound, the two strands separate and straighten out, resulting in a longer length.

A mutation can be passed on to offspring only when it is present during or occurs during meiosis. Meiosis is the process of cell division that produces gametes (sperm and egg cells) in sexually reproducing organisms. During meiosis, genetic material is shuffled and divided, resulting in the formation of haploid cells with unique combinations of genes. If a mutation is present in the DNA of the parent's reproductive cells (sperm or egg), it can be passed on to the offspring. Mutations that occur during mitosis or in somatic cells (non-reproductive cells) are not passed on to offspring.

Diagram 3 shows an insertion mutation because it has an extra nucleotide inserted into the DNA sequence compared to the original sequence. This type of mutation results in a shift in the reading frame and can lead to significant changes in the resulting protein.

The given answer, "Inversion of a part 180o," is the correct explanation for the type of mutation depicted in the figure. Inversion refers to a mutation where a segment of DNA is reversed within the chromosome. In this case, the figure shows a part of the chromosome being flipped 180 degrees, indicating an inversion mutation.

Diagram 1 demonstrates a deletion mutation because it shows a section of the DNA strand that has been removed or deleted. This is indicated by the gap in the DNA strand where a section of nucleotides is missing.

Insertion or deletion mutations can cause a frameshift in a DNA sequence. This is because insertion or deletion of nucleotides can disrupt the reading frame of the sequence, shifting the codon alignment and potentially leading to a completely different amino acid sequence during translation. In contrast, substitution mutations only change one nucleotide at a time and do not typically cause a frameshift. Inversion mutations involve rearranging sections of DNA but do not result in a frameshift. Saturation mutations refer to a high frequency of mutations in a specific region but do not directly cause frameshifts.

None of the diagrams demonstrate an inversion of nucleotides. An inversion mutation occurs when a segment of DNA is reversed within the chromosome. In the given diagrams, there is no indication of any segment being reversed or inverted. Therefore, none of the diagrams represent an inversion mutation.

Mitochondria and plastids are organelles in eukaryotes that carry DNA molecules. Mitochondria are responsible for producing energy in the form of ATP through cellular respiration and have their own DNA. Plastids, such as chloroplasts, are involved in photosynthesis and also contain their own DNA. This DNA is separate from the DNA found in the nucleus of the cell.

The given figure represents an exchange of segments between two non-homologous chromosomes. This type of mutation is known as a chromosomal translocation, where a segment of one chromosome breaks off and attaches to a non-homologous chromosome. This can lead to changes in the structure and function of the affected chromosomes, potentially causing genetic disorders or abnormalities.

A chromosome is a structure in the cell that contains genes. Genes are segments of DNA that provide instructions for making proteins. Therefore, a chromosome contains multiple genes, and these genes are composed of DNA.

The correct answer is "Same." Eukaryotic cells contain a number of DNA molecules equal to the number of chromosomes inside them. This means that each chromosome in a eukaryotic cell contains a single DNA molecule. Therefore, the number of DNA molecules is the same as the number of chromosomes.

Spontaneous mutations can occur naturally without any external factors or human interference. One possible cause of spontaneous mutations is exposure to ultraviolet (UV) radiation. UV radiation can cause damage to the DNA molecule, leading to changes in the genetic code and the occurrence of mutations. Therefore, the correct answer is Ultra violet.

A deletion mutation in a non-coding sequence of nucleotides will have no effect on the DNA molecule because non-coding sequences do not code for proteins or functional RNA molecules. These sequences are not involved in the production of gene products, so any mutation occurring in them will not impact the organism's phenotype or cause any significant problems. Therefore, the deletion mutation will have no effect on the organism.

The DNA is tightly bound to histones due to the strong binding between the negatively charged amino acids of histones and the positively charged phosphate groups of DNA. This electrostatic interaction between the opposite charges helps to stabilize the DNA-histone complex and keeps the DNA tightly wrapped around the histones.

The given statement "All mutations are spontaneous" is incorrect. Mutations can occur spontaneously, but they can also be induced by various factors such as exposure to radiation or chemicals. Therefore, not all mutations are spontaneous.

A plasmid is a small, circular DNA molecule that is separate from the chromosomal DNA in a cell. It usually contains genes that provide some advantage to the organism, such as antibiotic resistance. In a plasmid, the phosphate groups are part of the DNA backbone, and they are essential for the stability and structure of the molecule. However, in this question, the correct answer is zero, which suggests that there are no free phosphate groups in the plasmid. This implies that the phosphate groups are either bound to other molecules or are not present in the plasmid at all.

DNA replication in yeast fungus takes place in both the nucleus and cytoplasm. The nucleus is the primary site for DNA replication, where the majority of the replication machinery is located. However, yeast cells also have a small amount of DNA replication occurring in the cytoplasm, specifically in the mitochondria. This is because mitochondria have their own circular DNA molecules that need to be replicated independently from the nuclear DNA. Therefore, DNA replication in yeast fungus occurs in both the nucleus and cytoplasm.

not-available-via-ai

More than 30% of the Eukaryotic genome does not represent coding sequences in the DNA. This means that less than 30% of the Eukaryotic genome is involved in synthesizing proteins or RNA. The other options, such as most of the prokaryotic genome and sequences for synthesizing proteins and RNA, do represent coding sequences in the DNA.

The given sequence of nucleotides has undergone a deletion mutation. This is evident from the fact that in the original DNA sequence "CAT GAT", a nucleotide "G" has been deleted in the new DNA sequence "CAT AT". Deletion mutation refers to the removal of one or more nucleotides from the DNA sequence, leading to a change in the genetic code.

The original sequence "ABCDEF" has undergone an inversion mutation to become "ACEFBD". In an inversion mutation, a segment of the DNA sequence is reversed or flipped in orientation. In this case, the segment "CDEF" has been inverted to become "FEDC". This type of mutation can lead to changes in the function of genes and can have significant effects on the organism.

The given gene sequence "ABC" has undergone a mutation where the nucleotide "A" has been replaced by "B", resulting in the new gene sequence "BBC". This type of mutation, where one nucleotide is substituted for another, is known as a substitution mutation.

Colchicine can induce polyploidy in plants by interfering with various stages of cell division. It can prevent the separation of chromatids after centromeric division, inhibit the formation of spindle fibers during cell division, and cause failure of membrane formation between daughter cells. Therefore, any of these actions can contribute to the induction of polyploidy by colchicine.

Regulatory proteins determine whether or not the DNA sequence is a code for making ligase enzymes. These proteins play a crucial role in gene expression by binding to specific DNA sequences and controlling the transcription and translation processes. In this case, regulatory proteins would bind to the DNA sequence responsible for coding the ligase enzymes, thereby determining whether or not they are produced. Structural histones, structural non-histones, and chromatin are not directly involved in determining the coding potential of a DNA sequence.

The correct answer is that the DNA in prokaryotic cells is coiled compactly, so if it was stretched out, it would be much longer than the cell itself. This is because prokaryotic cells have a small and simple structure, so their DNA needs to be tightly packed to fit inside the cell. This compact coiling allows for efficient storage of genetic information in a small space.

not-available-via-ai

DNA can serve as a template for DNA or RNA synthesis when it is in the form of a string of nucleosomes. Nucleosomes are the basic structural units of chromatin, consisting of DNA wrapped around histone proteins. This coiled structure allows for efficient packaging of DNA and regulates gene expression. When DNA is in the form of a string of nucleosomes, it is accessible for transcription and replication, making it a suitable template for DNA or RNA synthesis.

Regulatory proteins are responsible for turning on or off specific genes within a cell. They bind to specific DNA sequences and either enhance or inhibit the transcription of those genes. This process allows cells to control gene expression and ensure that only the necessary genes are turned on at any given time. Histones and nucleosomes are involved in packaging and organizing DNA, while other structural proteins provide support and structure to the cell. However, neither of these directly regulate gene expression like regulatory proteins do.

Histone proteins have a primary function of tightly coiling and packaging large amounts of DNA into a small space. This allows the long DNA molecules to be condensed and organized into compact structures called chromosomes. By wrapping around the DNA, histones help to maintain the integrity and stability of the DNA molecule, while also regulating its accessibility for gene expression and replication. This packaging is essential for the efficient storage and transmission of genetic information during cell division and other cellular processes.

The correct order of organization of the eukaryotic chromosome is as follows: DNA double helix ⟶ nucleosome ⟶ chromatin ⟶ chromosome. This is because the DNA double helix is wrapped around histone proteins to form nucleosomes, which then further condense and fold to form chromatin. Finally, the chromatin fibers condense and coil to form the visible chromosome structure.

Non-histone proteins have multiple roles within the chromatin. They include structural proteins, which help in organizing and maintaining the structure of DNA within the nucleus. Additionally, they also include regulatory proteins that play a role in both RNA synthesis and protein synthesis. Therefore, all of the given answers are correct as they encompass the various roles of non-histone proteins within the chromatin.

The correct answer is Y because Y on the diagram indicates a histone. Histones are proteins that help in the packaging of DNA into a condensed structure called chromatin. They play a crucial role in organizing and regulating the DNA in eukaryotic cells.

The chromosomal DNA in prokaryotes is typically a single, circular, double-stranded DNA molecule. This means that the DNA is not divided into multiple linear sections or small circular loops. Additionally, it is not a short, linear, single-stranded DNA molecule. The structure of the chromosomal DNA in prokaryotes is not thread-like and coiled into an X shape, as that is characteristic of the condensed form of DNA during cell division.