Ch. 9 How Cells Reproduce

Meiosis is the process of cell division that occurs in the reproductive cells, known as gametes. Gametes are specialized cells that are involved in sexual reproduction and carry half the number of chromosomes compared to the parent cell. During meiosis, the parent cell undergoes two rounds of division, resulting in the formation of four genetically unique gametes. These gametes, such as sperm and egg cells, combine during fertilization to form a new individual with a complete set of chromosomes. Therefore, the correct answer is gametes.

During mitosis, the "spindle" fibers are responsible for moving the chromosomes. The spindle fibers attach to the chromosomes and help to separate them into two sets, ensuring that each daughter cell receives the correct number of chromosomes. The term "spindle" begins with the letter S, as indicated in the clue.

Mitosis is a type of cell division that results in the formation of two daughter cells. These daughter cells are identical to the parent cell and each contain the same number of chromosomes. Since mitosis involves the replication and separation of chromosomes, the daughter cells end up with two sets of chromosomes, which is also referred to as diploid. Therefore, the correct answer is 2 or two.

Eukaryotic organisms undergo mitosis, which is the process of cell division that results in two identical daughter cells. In addition to mitosis, eukaryotic organisms also undergo meiosis. Meiosis is a specialized form of cell division that occurs in reproductive cells and results in the production of gametes (sperm and eggs) with half the number of chromosomes as the parent cell. This process is essential for sexual reproduction and genetic diversity in eukaryotes.

A chromosome is a DNA molecule and attached proteins. These proteins are called histones. Chromosomes are structures found in the nucleus of cells and contain the genetic information in the form of genes. They play a crucial role in the transmission of genetic material from one generation to the next during cell division and reproduction.

Haploid refers to having a single set of chromosomes, which is the case in gametes (sperm and egg cells). In contrast, diploid refers to having two sets of chromosomes, which is the normal condition in most cells of the body. Triploid refers to having three sets of chromosomes, which is an abnormal condition that can occur due to errors during cell division. Therefore, the correct answer is haploid.

When a chromosome is duplicated from 1 strand to 2 strands, the 2 strands are called sister chromatids. They are attached by a centromere. This term is used to describe the two identical copies of a chromosome that are formed during the process of DNA replication. The sister chromatids are held together by the centromere, which allows them to be separated and distributed to daughter cells during cell division.

Gametes are reproductive cells that are involved in sexual reproduction. In the case of humans and many other animals, there are two types of gametes: eggs (also known as ova or oocytes) and sperm cells. Eggs are produced by the female reproductive system, while sperm cells are produced by the male reproductive system. Both eggs and sperm cells are necessary for fertilization to occur and for the creation of offspring.

Diploid organisms have two sets of chromosomes, with one set coming from the mother and one set from the father. This means that they have two copies of each chromosome, allowing for genetic diversity and the ability to inherit traits from both parents.

Humans have 23 pairs of chromosomes, with a total of 46 chromosomes. Each pair consists of one chromosome inherited from the mother and one from the father, resulting in a total of 46 chromosomes in each cell of the human body.

Prokaryotic organisms undergo prokaryotic fission because they are single-celled organisms that lack a nucleus and other membrane-bound organelles. Prokaryotic fission is a form of asexual reproduction where the parent cell divides into two identical daughter cells. This process occurs in bacteria and archaea, which are examples of prokaryotes. Eukaryotic organisms, on the other hand, have a true nucleus and undergo mitosis or meiosis for reproduction. Therefore, the correct answer is Prokaryotic.

Mitosis is the process of cell division for growth and cell replacement. In some invertebrates, mitosis is used for asexual reproduction. Asexual reproduction involves the production of offspring without the involvement of gametes or the fusion of genetic material from two parents. In mitosis, a single cell divides into two identical daughter cells, each with the same genetic material as the parent cell. This allows for the production of genetically identical offspring, which is characteristic of asexual reproduction.

Somatic cells refer to all the cells in the body except for the reproductive cells (eggs and sperm). These cells make up the tissues, organs, and systems of the body and are responsible for carrying out specific functions necessary for the body's survival and functioning. The term "somatic" is derived from the Greek word "soma," which means "body." Therefore, the correct answer is "somatic."

Mitosis is the correct answer because it is a type of cell division that results in daughter cells that are genetically identical to the parent cell. During mitosis, the cell's DNA is replicated and evenly distributed into two daughter cells, ensuring that they have the same genetic information as the parent cell. Meiosis, on the other hand, is a type of cell division that results in daughter cells with half the number of chromosomes as the parent cell and leads to genetic variation. Therefore, meiosis does not produce daughter cells that are exactly like the parent cells.

Gametes are produced by meiosis. Meiosis is a type of cell division that occurs in the reproductive cells, resulting in the formation of gametes (sperm and egg cells). Unlike mitosis, which produces identical cells, meiosis involves two rounds of division, resulting in the formation of four non-identical daughter cells with half the number of chromosomes as the parent cell. This process is essential for sexual reproduction, as it ensures genetic diversity in offspring by shuffling and recombining genetic material.

Gametes are haploid cells, meaning they contain half the number of chromosomes compared to other cells in the body. This is necessary for sexual reproduction because when two gametes fuse during fertilization, they form a diploid zygote with the full complement of chromosomes. The haploid state ensures that the resulting offspring will have the correct number of chromosomes and genetic diversity.

Before mitosis occurs, the chromosome duplicates. This means that it makes an exact copy of itself, resulting in two identical sister chromatids held together by a centromere. This duplication is necessary for the proper distribution of genetic material to daughter cells during cell division.

The term "diploid" refers to having two sets of each type of chromosome in a cell or organism. In humans, for example, diploid cells have 23 pairs of chromosomes, with one set inherited from each parent. This is in contrast to "haploid," which refers to having only one set of chromosomes, and "triploid," which refers to having three sets of chromosomes. Therefore, "diploid" is the correct answer to describe the condition of having two of each type of chromosome.

Interphase is the longest phase of the cell cycle because it encompasses the majority of the cell's life cycle. During interphase, the cell grows, carries out its normal functions, and replicates its DNA in preparation for cell division. This phase can be further divided into three stages: G1, S, and G2. G1 is the growth phase where the cell increases in size, S is the DNA synthesis phase where the cell replicates its DNA, and G2 is the second growth phase where the cell prepares for division. Overall, interphase is a crucial period for the cell to prepare for cell division and ensure proper growth and function.

During the S phase of the cell cycle, DNA replication takes place. This is the phase where the cell synthesizes a copy of its DNA in order to prepare for cell division. 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 each daughter cell receives an identical copy of the genetic material. Therefore, the correct answer is S phase.

Mitosis refers to the process of cell division in which a single cell divides into two identical daughter cells. During mitosis, the nucleus of the cell undergoes rapid nuclear division, resulting in the formation of two daughter nuclei. This process is crucial for growth, repair, and asexual reproduction in organisms. Therefore, the correct answer is mitosis.

Somatic cells are diploid because they contain two sets of chromosomes, one inherited from each parent. These cells make up the majority of our body tissues and organs. In contrast, gametes (reproductive cells) are haploid, meaning they only have one set of chromosomes. Chromatic cells are not a recognized term in biology, so they cannot be considered diploid or haploid.

After mitosis, the cytoplasm divides through a process called cytokinesis. In plants, a new cell wall is formed in the middle of the cell, which eventually separates the two daughter cells. This process is known as cell plate formation. On the other hand, in animal cells, the cytoplasm constricts along the equator of the cell, forming a cleavage furrow that pinches the cell into two daughter cells. Therefore, the correct answer is "cell" because plants undergo cell plate formation, while animal cells undergo cleavage.

The cell cycle has a built-in checkpoint in the G1 phase. This checkpoint ensures that the cell has all the necessary nutrients and conditions to proceed with the cell division process. If the checkpoint detects any abnormalities or damage to the DNA, it can halt the cell cycle and initiate repairs or trigger cell death. Many cancer cells occur because this checkpoint in the G1 phase is defective, allowing damaged cells to continue dividing and proliferating uncontrollably.

Interphase is the correct answer because during this phase, cells are in a resting state and not actively dividing. This is the longest phase of the cell cycle and is characterized by cell growth, DNA replication, and preparation for cell division. Brain and nerve cells are examples of cells that typically stay in interphase and do not undergo further division. Metaphase and telophase are stages of cell division, so they are not the correct answers.