Exam 3 Bio 113 DNA/RNA Structure, Cell Cycle, Mitosis

A double helix structure describes DNA. DNA is a molecule that carries the genetic instructions used in the growth, development, functioning, and reproduction of all known living organisms. The double helix structure refers to the twisted ladder-like shape formed by two strands of nucleotides, which are the building blocks of DNA. This structure allows for the efficient storage and replication of genetic information. RNA, mitosis, and the cell cycle are not specifically characterized by a double helix structure.

Deoxyribose sugar is a component of DNA, which is a molecule that carries genetic information in all living organisms. RNA also contains a sugar called ribose, not deoxyribose. Amino acids are the building blocks of proteins, and phosphate is a component of DNA and RNA, but deoxyribose sugar is specifically found in DNA.

A diploid cell refers to a cell that contains two sets of chromosomes, one set inherited from each parent during sexual reproduction. This means that diploid cells have pairs of homologous chromosomes, with one chromosome from each pair coming from the mother and the other from the father. This is in contrast to haploid cells, which only have one set of chromosomes and are typically found in gametes (sperm and egg cells). Therefore, the given answer correctly states that a diploid cell has two sets of chromosomes, reflecting its origin from two parents.

A haploid cell is a cell that contains only one set of chromosomes, which means it has half the number of chromosomes compared to a diploid cell. This suggests that the cell is derived from only one parent. In contrast, a diploid cell has two sets of chromosomes, one from each parent. Therefore, the correct answer is a haploid cell.

During metaphase, chromosomes line up in the middle of the cell and condense. This is an important stage of cell division, specifically in mitosis and meiosis, where the chromosomes become visible and are organized along the equatorial plane of the cell. The alignment of the chromosomes in the middle ensures that they will be properly separated and distributed to the daughter cells during the subsequent stages of cell division.

The point of attachment for chromatids is called centromeres. Centromeres are specialized regions on chromosomes where the two sister chromatids are held together. During cell division, the centromeres play a crucial role in ensuring that each daughter cell receives the correct number of chromosomes.

Mitosis is a process of cell division that results in the production of two identical daughter cells. During mitosis, the parent cell's genetic material is replicated and evenly distributed to the two daughter cells, ensuring that they have the exact same genetic component as the parent cell. Therefore, the correct answer is that mitosis produces two identical cells containing the exact same genetic component.

The cell cycle refers to the sequence of events that a cell goes through from its formation to its division into two daughter cells. It includes interphase, where the cell grows and prepares for division, and mitosis, where the cell's nucleus divides into two identical sets of chromosomes. The cell cycle is crucial for the growth, development, and reproduction of cells, ensuring that genetic material is accurately passed on to daughter cells. Therefore, the cell cycle is the correct answer as it encompasses all the processes a cell undergoes during its lifespan.

Before mitosis, DNA replication has to occur. This is because DNA replication ensures that each daughter cell receives an exact copy of the genetic material present in the parent cell. During DNA replication, the DNA molecule unwinds and separates into two strands, and each strand serves as a template for the synthesis of a new complementary strand. This process ensures that the genetic information is accurately duplicated and distributed to the daughter cells during mitosis.

Mitosis is a process of cell division that begins with a cell or nucleus containing a specific genetic composition. During mitosis, the genetic material is replicated and distributed equally into two daughter cells. This ensures that each new cell receives the same genetic information as the parent cell. Therefore, the correct answer is "cell/nucleus with a certain genetic composition."

Ribose sugar is found in RNA. RNA, or ribonucleic acid, is a molecule that plays a crucial role in protein synthesis. It is made up of a single strand of nucleotides, which are the building blocks of RNA. Each nucleotide consists of a phosphate group, a ribose sugar, and a nitrogenous base. The presence of ribose sugar in RNA distinguishes it from DNA, which contains deoxyribose sugar. Therefore, the correct answer is RNA.

Meiosis is the correct answer because it is the process by which sex cells, also known as gametes, are formed. During meiosis, a single cell divides twice, resulting in four genetically unique cells, each containing half the number of chromosomes as the original cell. This is essential for sexual reproduction as it allows for the combination of genetic material from two parents, resulting in genetic diversity in offspring. Mitosis, on the other hand, is the process of cell division that occurs in somatic cells for growth and repair. Transcripted and translated are not relevant processes for the formation of sex cells.

During the telephase of cell division, the replicated chromosomes move to opposite ends of the cell and a new nuclear membrane begins to form around each set of chromosomes. This is the final stage of cell division before the cell fully separates into two new cells, making telephase the correct answer.

Cytokinesis refers to the process of cell division, specifically the division of the cytoplasm and the separation of the two daughter cells. It is the final stage of cell division, following the separation of the chromosomes during mitosis or meiosis. The other options listed, karyotkinesus, karyotype, and autosomes, are unrelated to cell division and do not pertain to the given statement.

Sister chromatids are the replicated strands of DNA that are attached at the centromere. During DNA replication, the DNA molecule duplicates itself, resulting in two identical sister chromatids. These sister chromatids are held together by proteins at the centromere and are essential for cell division. They separate during mitosis or meiosis, ensuring that each daughter cell receives a complete set of chromosomes. Therefore, sister chromatids accurately describe the situation where two replicated DNA strands are attached at the centromere.

During anaphase, the sister chromatids start being pulled apart away from each other. This phase of mitosis is characterized by the separation of the sister chromatids, which are identical copies of each other formed during DNA replication. The spindle fibers attached to the centromeres of the sister chromatids contract, causing them to move towards opposite poles of the cell. This ensures that each daughter cell receives a complete set of chromosomes.

During the S phase of the cell cycle, DNA is synthesized. This is the phase where DNA replication occurs, and each chromosome is duplicated to form two identical sister chromatids. The S phase is a crucial step in cell division as it ensures that each daughter cell receives a complete set of genetic information.

Mitosis is the process of cell division, where a single cell divides into two identical daughter cells. During mitosis, the nucleus of the cell undergoes division, resulting in the distribution of genetic material to the daughter cells. Therefore, mitosis occurs in the nucleus of the cell. The cytoplasm, ribosomes, and Golgi body are all involved in various cellular functions, but they do not directly participate in the process of mitosis.

During the M phase of the cell cycle, cytokinesis occurs. This is the phase where the cell undergoes division, resulting in two daughter cells. Cytokinesis is the process by which the cytoplasm of the cell is divided into two separate cells. It occurs after the nuclear division, which takes place during the previous phase called mitosis. Therefore, the correct answer is M phase.

Hydrogen bonds are the types of bonds found between nitrogen bases in DNA. These bonds are formed between the nitrogenous bases adenine (A) and thymine (T), as well as between guanine (G) and cytosine (C). Hydrogen bonds are relatively weak, allowing for the separation and replication of DNA strands during processes like transcription and DNA replication.

The nitrogen bonds found in DNA are A-T and C-G. These bonds are formed between specific nitrogenous bases. Adenine (A) always pairs with thymine (T), and cytosine (C) always pairs with guanine (G). These base pairs are held together by hydrogen bonds, forming the double helix structure of DNA.

DNA replication occurs during the S phase of the cell cycle. This is the phase where the cell's DNA is duplicated in preparation for cell division. During the S phase, the DNA unwinds and separates into two strands, and each strand serves as a template for the synthesis of a new complementary strand. This process ensures that each daughter cell receives an identical copy of the genetic material. The G1 phase is the first gap phase before DNA replication, the G2 phase is the second gap phase after DNA replication, and the M phase is the phase where cell division occurs.

A nucleotide is a subunit for DNA, which is composed of a sugar. Nucleotides are the building blocks of DNA and consist of a sugar molecule, a phosphate group, and a nitrogenous base (either purine or pyrimidine). Therefore, nucleotide is the correct answer in this context.

An allele is a variant form of a gene that is located at a specific position on a specific chromosome. Alleles can occur in pairs, with one allele inherited from each parent. They determine the different traits or characteristics that an organism may have. Therefore, the correct answer for the type of a gene is allele.

Y chromosomes are the smallest chromosomes and contain few genes compared to other chromosomes. They are found in males and determine male sex characteristics. The Y chromosome is responsible for the development of testes and the production of sperm. It plays a crucial role in determining the sex of an individual, as males have one X and one Y chromosome, while females have two X chromosomes. Therefore, the given answer accurately describes the characteristics of Y chromosomes.

During the prophase of cell division, chromosomes condense and become visible under a microscope. Additionally, the spindle fibers start to form and attach to the centromeres of the condensed chromosomes. This phase marks the beginning of mitosis or meiosis, where the genetic material is prepared for separation and distribution to daughter cells.

Homologous chromosomes are pairs of chromosomes that contain the same genes, but may have different alleles. They are similar in size, shape, and carry genetic information for the same traits. During meiosis, homologous chromosomes pair up and exchange genetic material through a process called crossing over. This genetic exchange leads to genetic variation and the production of gametes with different combinations of alleles. Therefore, homologous chromosomes are the correct answer as they exhibit the characteristic of containing the same genes but different alleles.

Somatic cells undergo mitosis, which is a type of cell division that results in two identical daughter cells. This process is responsible for the growth, repair, and maintenance of body tissues. Unlike meiosis, which is involved in the production of gametes (sex cells), mitosis produces cells with the same number of chromosomes as the parent cell. Therefore, the correct answer is mitosis.

A purine is a nitrogenous base that consists of two carbon-nitrogen rings. It is one of the two types of nitrogenous bases found in DNA and RNA, the other being pyrimidine. Purines include adenine and guanine, while pyrimidines include cytosine, thymine (found in DNA), and uracil (found in RNA). Therefore, the correct answer is purine.

The M phase, also known as mitosis, is the process where chromosomes are sorted and divided into two new cells or nuclei. During this phase, the cell undergoes a series of steps including prophase, metaphase, anaphase, and telophase, which result in the separation of the duplicated chromosomes and the formation of two identical daughter cells. This ensures that each new cell receives the correct number and type of chromosomes, maintaining the genetic stability and integrity of the organism.

Pyrimidine is the correct answer because it is a nitrogenous base that consists of only one carbon-nitrogen ring. Purine, on the other hand, has two carbon-nitrogen rings. DNA and RNA are not nitrogenous bases; they are nucleic acids that contain nitrogenous bases, including pyrimidines and purines.

The correct answer is "nucleotide sequence". Genetic information refers to the sequence of nucleotides in DNA or RNA molecules. Nucleotides are the building blocks of DNA and RNA, and they consist of a nitrogenous base, a sugar molecule, and a phosphate group. The sequence of these nucleotides determines the genetic code, which carries the instructions for the synthesis of proteins and the functioning of cells. Therefore, the nucleotide sequence is essential for the transmission and expression of genetic information.

In RNA, the nitrogen bonds that are found are A-U and C-G. Adenine (A) forms a hydrogen bond with Uracil (U), while Cytosine (C) forms a hydrogen bond with Guanine (G). These base pairs are essential for the stability and structure of RNA molecules. The other options listed, A-T, G-A, and T-U, are not found in RNA.

The given answer, thymine and cytosine, is correct because they are both examples of pyrimidine bases. Pyrimidines are one of the two types of nitrogenous bases found in DNA and RNA, the other being purines. Thymine and cytosine are two of the four bases that make up DNA, along with adenine and guanine. They are responsible for the genetic code and play a crucial role in the structure and function of DNA molecules.

A karyotype is a visual representation of an individual's chromosomes, typically arranged in pairs according to size, shape, and other characteristics. It allows for the identification of any chromosomal abnormalities or genetic disorders. The other options, autosomes, diploid, and haploid, are related to the number and type of chromosomes but do not specifically refer to a visual representation like a karyotype does.

The correct answer is adenine and guanine because both of these molecules are classified as purines. Purines are nitrogenous bases that are found in DNA and RNA, and they consist of a double-ring structure. Adenine and guanine both have this double-ring structure, making them examples of purines.

When an individual receives one gene from their mother and another gene from their father, these genes are located on homologous chromosomes. Homologous chromosomes are pairs of chromosomes that contain the same genes, but may have different versions of those genes. They are similar in size, shape, and gene content, and are involved in the process of genetic recombination during meiosis. Therefore, the correct answer is homologous chromosome.

Hydrogen bonds between nitrogen bases in opposing complementary strands are responsible for linking the two strands of DNA to form a double helix. These hydrogen bonds occur specifically between adenine and thymine, and between guanine and cytosine. The nitrogen bases play a crucial role in maintaining the stability and structure of DNA, allowing for accurate replication and transmission of genetic information.

The G2 phase is the third phase of the cell cycle, following the S phase. During this phase, the cell prepares for mitosis by ensuring that DNA replication has occurred correctly in the previous S phase. The G2 phase allows for any errors or damages in the DNA to be repaired before the cell proceeds to the M phase, where mitosis takes place. Therefore, the G2 phase is crucial in ensuring that mitosis occurs correctly by allowing for DNA repair and proper preparation of the cell.

Sex chromosomes are a pair of chromosomes that determine the sex of an individual. Unlike autosomes, which are the other pairs of chromosomes, sex chromosomes are not necessarily the same size, shape, or have the same genes. In humans, for example, females have two X chromosomes (XX), while males have one X and one Y chromosome (XY). This difference in sex chromosomes is what determines the sexual characteristics and reproductive system of an individual.

The X chromosome is the correct answer because it is a full-size chromosome that contains many genes. In humans, females have two X chromosomes, while males have one X and one Y chromosome. The X chromosome plays a crucial role in determining the biological sex of an individual and carries genes responsible for various traits and characteristics.

Nucleotides consist of a phosphate group, a nitrogen-containing base, and a deoxyribose sugar. The phosphate group provides the backbone structure for the nucleotide, while the nitrogen-containing base determines the nucleotide's identity and can be adenine, thymine, cytosine, or guanine. The deoxyribose sugar is a five-carbon sugar that is attached to the nitrogen-containing base. These components together form the basic building blocks of DNA and RNA molecules.

Karytkinesis is the correct answer because it refers to the process of nuclear division. This term specifically describes the division of the nucleus during cell division, where the chromosomes are separated and distributed into two daughter cells. Cytokinesis, on the other hand, is the division of the cytoplasm, which follows karytkinesis. Karyotype refers to the number and appearance of chromosomes in an individual, and autosome refers to any chromosome that is not a sex chromosome.

The correct answer is James Watson, Francis Crick, and Maurice Wilkins. These three individuals are credited with the discovery of the structure of DNA. James Watson and Francis Crick are particularly well-known for their model of the double helix structure of DNA, which they published in 1953. Maurice Wilkins also made significant contributions to the understanding of DNA structure through his X-ray crystallography work.

The G1 phase is the first phase of the cell cycle, where the cell prepares for DNA replication and cell division. During this phase, the cell grows in size, synthesizes proteins and organelles, and carries out normal metabolic activities. It also checks for any DNA damage and ensures that the cell is ready to proceed to the S phase, where DNA replication occurs. Therefore, the G1 phase is responsible for making sure that the cell is ready to divide by ensuring that all necessary preparations have been made.

The correct order of the stages of the cell cycle is G1 phase, S phase, G2 phase, and M phase. This is because the cell first goes through a period of growth and preparation (G1 phase), followed by DNA replication (S phase), further growth and preparation (G2 phase), and finally mitosis (M phase) where the cell divides into two daughter cells. Therefore, the correct answer is 2,3,4,1.

Autosomes are pairs of chromosomes that are the same size, shape, and have the same genes. They are responsible for determining the characteristics and traits that are not related to sex determination. In humans, there are 22 pairs of autosomes. On the other hand, sex chromosomes are responsible for determining the sex of an individual and are not identical in size, shape, or gene composition. Homologous chromosomes, on the other hand, are pairs of chromosomes that carry the same genes, but they may not be the same size or shape. Therefore, the correct answer is autosomes.

The sugars in DNA differ from those in RNA because DNA is missing an oxygen in the sugar, while RNA has an additional oxygen. DNA's sugar, deoxyribose, has only two oxygens, whereas RNA's sugar, ribose, has three oxygens. This difference in sugar structure is one of the key distinctions between DNA and RNA molecules.