Mastering Biology Chapter 13 HW

Chapter 13 Pre-Test Question 1

Asexual reproduction _____.

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Chapter 13 Pre-Test Question 5

How are sister chromatids and homologous chromosomes different from each other?

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Meiosis (1 of 3): Genes, Chromosomes, and Sexual Reproduction (BioFlix tutorial)

Part A – Meiosis terminology

Drag the labels from the left to their correct locations in the concept map on the right.

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Part B – Interactions among chromosomes

This diagram shows a diploid nucleus (2n=8) in which chromosome replication has occurred in preparation for mitosis (top) and meiosis (bottom). The nucleus at top right is now in prophase of mitosis; the nucleus at bottom right is now in prophase I of meiosis. Drag the labels to their appropriate targets to correctly identify the various chromosome structures. Labels can be used more than once.

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Part C – Animal life cycles

In the life cycle of an organism, meiosis is paired with the process of fertilization. Understanding the life cycle of an organism is the key to understanding how sexual reproduction ensures the inheritance of traits from both parents and also introduces genetic variation. Complete the diagram to show the life cycle of a typical animal. Follow these steps: First, drag blue labels onto blue targets only to identify each stage of the life cycle. Next, drag pink labels onto pink targets only to identify the process by which each stage occurs. Then, drag white labels onto white targets only to identify the ploidy level at each stage. Labels can be used once, more than once, or not at all.

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Meiosis (2 of 3): The Mechanism (BioFlix tutorial)

Part A – The stages of meiosis

Can you recognize the eight stages of meiosis based on the location and behavior of the chromosomes? Drag the diagrams of the stages of meiosis onto the targets so that the four stages of meiosis I and the four stages of meiosis II are in the proper sequence from left to right. (Note that only one of the two daughter cells is shown for meiosis II.)

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Part B – Crossing over

Crossing over plays a critical role in increasing the genetic variation among offspring of sexual reproduction. It is important to understand how crossing over occurs and its consequences in meiosis. Look carefully at the diagrams depicting different stages in meiosis in a cell where 2n = 6. Assume that the red chromosomes are of maternal origin and the blue chromosomes are of paternal origin. Drag the labels to fill in the targets beneath each diagram of a cell. Note that the diagrams are in no particular order. Drag the blue labels to the blue targets to identify the stage of meiosis depicted in each diagram. Drag the pink labels to the pink targets to identify whether the configuration of the chromosomes related to crossing over is possible or not.

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Part C – Changes in ploidy and DNA content during meiosis

The parent cell that enters meiosis is diploid, whereas the four daughter cells that result are haploid. Which statement correctly describes how cellular DNA content and ploidy levels change during meiosis I and meiosis II?

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Meiosis (3 of 3): Determinants of Heredity and Genetic Variation (BioFlix tutorial)

Part A – Processes that determine heredity and contribute to genetic variation

Meiosis guarantees that in a sexual life cycle, offspring will inherit one complete set of chromosomes (and their associated genes and traits) from each parent. The transmission of traits from parents to offspring is called heredity. Another important aspect of meiosis and the sexual life cycle is the role these processes play in contributing to genetic variation. Although offspring often resemble their parents, they are genetically different from both of their parents and from one another. The degree of variation may be tremendous. The following processes are associated with meiosis and the sexual life cycle: DNA replication before meiosis crossing over chromosome alignment in metaphase I and separation in anaphase I chromosome alignment in metaphase II and separation in anaphase II fertilization Sort each process into the appropriate bin according to whether it contributes to heredity only, genetic variation only, or both. (Note that a bin may be left empty.)

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Part B – Independent assortment and genetic variation

Consider a diploid cell where 2n = 6. During metaphase I of meiosis, as the pairs of homologous chromosomes line up on the metaphase plate, each pair may orient with its maternal or paternal homolog closer to a given pole. There are four equally probable arrangements of the homologous pairs at metaphase I. (Note that this problem assumes that no crossing over has occurred.) Four diagrams showing four equally probable arrangements of three homologous pairs at metaphase I. In arrangement 1, the pairs are from top to bottom: red-blue, red-blue, red-blue. In arrangement 2, the pairs are from top to bottom: red-blue, blue-red, blue-red. In arrangement 3, the pairs are from top to bottom: red-blue, blue-red, red-blue. In arrangement 4, the pairs are from top to bottom: red-blue, red-blue, blue-red. The cells below show the eight possible combinations of chromosomes that the daughter cells of meiosis II can receive. Sort each daughter cell into the appropriate bin depending on which arrangement at metaphase I would create it.

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Part C – Crossing over and genetic variation

Assume that an organism exists in which crossing over does not occur, but that all other processes associated with meiosis occur normally. Consider how the absence of crossing over would affect the outcome of meiosis. If crossing over did not occur, which of the following statements about meiosis would be true? Select all that apply.

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Question 13 Chapter 5

If we continued to follow the cell lineage from question 4, then the DNA content of a single cell at metaphase of meiosis II would be

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Misconception Question 62

Look at the cell in the figure. Based on this figure, which of the following statements is true?

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Misconception Question 63

What is the best evidence telling you whether this cell is diploid or haploid?

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Misconception Question 64

This chromosome has two chromatids, joined at the centromere. What process led to the formation of the two chromatids?

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Misconception Question 65

Two sister chromatids are joined at the centromere prior to meiosis. Which statement is correct?

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