Concept explainers
- a. How many chromosomes are in your somatic cells?
- b. How many chromosomes are in your gametes?
- c. How many chromatids are in one of your somatic cells that has duplicated its chromosomes prior to mitosis?
a.
To determine: The number of chromosomes in an individual’s somatic cell.
Introduction: Chromosomes are present in both prokaryotes and eukaryotes and make up the genetic material of an organism. Chromosomes are thin, thread-like structures visible at time of cell division. Chromosomes are actually DNA in compacted form that is held together by basic proteins known as histones.
Explanation of Solution
The chromosomes are diploid (2n) in number in the nucleus of somatic cells. Diploid refers to two sets of chromosomes in the same nucleus. Each somatic cell in humans consists of 46 chromosomes, which are two sets of 23 chromosomes each (maternal and paternal set). Therefore, an individual’s somatic cell contains 23 pairs that are 46 (2×23) chromosomes.
The number of chromosomes in an individual’s somatic cells is 46.
b.
To determine: The number of chromosomes in an individual’s gamete.
Introduction: Chromosome is a thread-like appearance of the nucleic acids and protein molecules present in the nucleus of various cells. Chromosome mainly contains the gene that bears the genetic information of one individual.
Explanation of Solution
The chromosome number explains the precise number of chromosomes present in specific species. In sexually reproducing organisms, gametes mainly contain haploid (n) number of chromosomes. Therefore, an individual’s gamete contains 23 chromosomes. The haploid number of chromosomes is produced during meiosis stage of cell division.
The number of chromosomes in an individual’s gamete is 23.
c.
To determine: The number of chromatids in an individual’s somatic cell that has duplicated its chromosomes prior to mitosis.
Introduction: Deoxyribonucleic acid (DNA) is the genetic material carried by every eukaryotic organism. Every DNA is made up of a pair of condensed chromatid subunits, and they are held together at a region called centromere.
Explanation of Solution
The number of chromosomes in an individual’s somatic cell is 46. The 46 chromosomes duplicate during the S phase of interphase prior to the process of mitosis. Therefore, 92 chromatids are present in an individual’s somatic cell that has duplicated its chromosomes prior to mitosis.
The number of chromatids in an individual’s somatic cell that has duplicated its chromosomes prior to mitosis is 92.
Want to see more full solutions like this?
Chapter 12 Solutions
Study Guide for Campbell Biology
- During which phases of the mitotic cycle would the terms chromosome and chromatid refer to identical structures?arrow_forwardFigure 10.6 Which of the following is the correct order of events in mitosis? Sister chromatids line up at the metaphase plate. The kinetochore becomes attached to the mitotic spindle. The nucleus reforms and the cell divides. Cohesin proteins break down and the sister chromatids separate. The kinetochore becomes attached to the mitotic spindle. Cohesin proteins break down and the sister chromatids separate. Sister chromatids line up at the metaphase plate. The nucleus reforms and the cell divides. The kinetochore becomes attached to the cohesin proteins. Sister chromatids line up at the metaphase plate. The kinetochore breaks down and the sister chromatids separate. The nucleus reforms and the cell divides. The kinetochore becomes attached to the mitotic spindle. Sister chromatids line up at the metaphase plate. Cohesin proteins break down and the sister chromatids separate. The nucleus reforms and the cell divides.arrow_forwardConsider a diploid organism with 18 chromosomes. Answer each question on a per cell basis. How many chromosomes are there during metaphase? How many functional centromeres are there during anaphase? How many chromosomes are there during telophase I after cytokinesis? How many chromosomes are there during prophase II? How many chromatids are there in anaphase II? How many kinds of chromosomes are there?arrow_forward
- 1. Draw Interphase and label cells in each stage of mitosis. 2. Draw prophase and label cells in each stage of mitosis. 3. Draw Metaphase and label cells in each stage of mitosis. 4. Draw Anaphase and label cells in each stage of mitosis 5. Draw Telophase and label cells in each stage of mitosis. 6. Draw Daughter Cells and label cells in each stage of mitosisarrow_forwardWhat is the specific structure of DNA during both the prophase and metaphase stages of mitosis?1.Condensed chromosomes2.Unreplicated chromosomes3.Single chromatid4.Separated chromatidsarrow_forwarda) In which stage of mitosis do chromosomes condense? (b) If a eukaryotic organism has a total of 34 chromosomes, how many pairs will the chromosomes be arranged in? (c) Define homologous chromosomes.arrow_forward
- Q1: Prior to going through meiosis, the nucleus would look like which letter? (Write just the letter below.) Q2: Next, the mitotic spindle fibers start to organize into centrosomes and these centrosomes pull away from each other, but since these images just show the nucleus, you don't see that here. While the mitotic spindle fibers are reorganizing, the DNA chromosomes start to condense, which you do see here. This is represented by what image? Q3: Once the DNA is completely condensed and organized into chromosomes, homologous chromosomes pair up in a process known as synapsis. This is represented by what image? Q4: Synapsis sets the homologous chromosomes up for crossing over when homologous chromosomes exchange parts of their DNA with each other. This is represented by what image Q5: At this point, the nuclear envelope is completely dissolved and no longer visible. The homologous chromosomes are lined up in the middle by the mitotic spindle fibers. This happens as the mitotic…arrow_forwarda. Explain how mitosis and meiosis are similar in their processes or mechanism using two examples. b. Explain how mitosis and meiosis are different in their processes or mechanism using two examples. **Please stay away from superficial statements such as both are a type of cell division. We are asking for a more detailed example based on how the cells proceed through the processes which has been highlighted in discussions, videos, and readings.arrow_forwardThe same chromosome can look very different depending on when in meiosis it is observed. Explain fully why this is so and also why the chromosome is less condensed during some parts of the cell cycle? How many DNA molecules does each chromosome contain at the beginning of Prophase I? Use the following terms in your explanation: chromatin, histone, chromatid, centromere.arrow_forward
- A Common Wombat has 14 chromosomes in one of its somatic (nonreproductive) cells. One of these cells goes into mitosis. How many cells result, and how many chromosomes does each one of these cells have?arrow_forwardDuring which phase(s) of the cell cycle are sister chromatids separated? a- meiosis I, meiosis II, and mitosis b- meiosis II c- meiosis I and mitosis d- meiosis II and mitosis e- meiosis Iarrow_forwardCan be more than one answer: Select all of the following that are true of MEIOSIS but not of MITOSIS. a) cell division occurs during cytokinesis b) results in two identical daughter cells c) halves the number of chromosomes in a cell d) spindle fibers contract during anaphase e) tetrads line up on metaphase platearrow_forward
- Human Heredity: Principles and Issues (MindTap Co...BiologyISBN:9781305251052Author:Michael CummingsPublisher:Cengage LearningConcepts of BiologyBiologyISBN:9781938168116Author:Samantha Fowler, Rebecca Roush, James WisePublisher:OpenStax CollegeHuman Biology (MindTap Course List)BiologyISBN:9781305112100Author:Cecie Starr, Beverly McMillanPublisher:Cengage Learning
- Biology 2eBiologyISBN:9781947172517Author:Matthew Douglas, Jung Choi, Mary Ann ClarkPublisher:OpenStax