Biology Chapter on Sexual Reproduction and Meiosis
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Questions and Answers

What does the term 'diploid' refer to?

  • A cell containing only one set of chromosomes.
  • A cell containing three sets of chromosomes.
  • A cell containing two complete sets of chromosomes. (correct)
  • A cell containing multiple sets of chromosomes.

What is the main function of meiosis in sexual reproduction?

  • To produce diploid cells for growth.
  • To duplicate DNA before cell division.
  • To split DNA into four haploid cells. (correct)
  • To create identical cells for tissue repair.

What is a karyotype used to visualize?

  • The alleles present for specific traits.
  • The number and appearance of chromosomes in an organism. (correct)
  • The organelles within a cell.
  • The genes present in an organism.

Which of the following is true about homologous pairs of chromosomes?

<p>They contain different alleles for the same genes. (B)</p> Signup and view all the answers

What does the term 'allele' refer to?

<p>A variation of a gene. (A)</p> Signup and view all the answers

In humans, how many pairs of autosomes are there?

<p>22 pairs (C)</p> Signup and view all the answers

Which chromosome pair typically determines an individual's sex?

<p>The last pair of chromosomes. (A)</p> Signup and view all the answers

What characteristic defines haploid cells?

<p>They contain a single set of chromosomes. (D)</p> Signup and view all the answers

What is the primary result of DNA exchange between homologous chromosomes?

<p>Creation of new combinations of DNA (B)</p> Signup and view all the answers

How many unique chromatids are created after DNA exchange between homologous chromosomes?

<p>4 unique chromatids (A)</p> Signup and view all the answers

Which process occurs in germ cells and results in unique cells?

<p>Meiosis (A)</p> Signup and view all the answers

What is the result of meiosis in terms of daughter cells?

<p>4 haploid daughter cells (C)</p> Signup and view all the answers

What defines the concept of polyploidy?

<p>Having more than two sets of chromosomes (B)</p> Signup and view all the answers

What is the total number of sperm and egg combinations possible before fertilization?

<p>70 trillion (D)</p> Signup and view all the answers

What important difference exists between mitosis and meiosis regarding chromosome alignment?

<p>Homologous chromosomes line up together in meiosis (A)</p> Signup and view all the answers

What is the probability of both parents being born, given the chance of an individual being born?

<p>1 in 4.9 x 10^27 (B)</p> Signup and view all the answers

What is a primary disadvantage of sexual reproduction compared to asexual reproduction?

<p>It requires more energy to attract mates. (B)</p> Signup and view all the answers

Which of the following best defines the concept of conjugation in bacteria?

<p>The exchange of genes between two bacteria. (A)</p> Signup and view all the answers

Why is genetic diversity considered a benefit of sexual reproduction?

<p>It creates unique genomes through gene mixing. (C)</p> Signup and view all the answers

Which statement about the energy expenditure in sexual reproduction is true?

<p>Some species use elaborate courtship rituals to attract mates. (C)</p> Signup and view all the answers

What role do mutations play in asexual organisms compared to sexual organisms?

<p>Asexual organisms depend on mutations for diversity, while sexual organisms mix genes. (C)</p> Signup and view all the answers

What occurs to the male angler fish after it finds a female?

<p>It attaches itself and becomes absorbed by the female. (C)</p> Signup and view all the answers

What is the main purpose of courtship rituals in sexual reproduction?

<p>To attract mates and ensure reproduction. (B)</p> Signup and view all the answers

How many pairs of chromosomes does a typical cell have?

<p>Two pairs of chromosomes are typical. (A)</p> Signup and view all the answers

What is the primary result of anaphase I during meiosis?

<p>Homologous chromosomes are pulled apart. (D)</p> Signup and view all the answers

What happens to the chromosomes during telophase I and cytokinesis?

<p>Nuclear envelopes reform around separated chromosomes. (C)</p> Signup and view all the answers

In which phase do spindle fibers reform and connect to the kinetochores of duplicated chromosomes?

<p>Prophase II (B)</p> Signup and view all the answers

What is created as a result of crossing over during meiosis?

<p>Recombinant chromosomes that enhance genetic diversity. (C)</p> Signup and view all the answers

What is a characteristic of the four cells produced at the end of meiosis?

<p>They are unique and haploid. (A)</p> Signup and view all the answers

What occurs during metaphase II of meiosis?

<p>Sister chromatids line up at the cell's equator. (A)</p> Signup and view all the answers

What distinguishes meiosis from mitosis in terms of the final cell products?

<p>Meiosis results in four unique haploid cells. (B)</p> Signup and view all the answers

During which part of meiosis do nuclear envelopes completely dissolve?

<p>Prophase II (B)</p> Signup and view all the answers

What does the term 'octoploid' refer to in terms of chromosome sets?

<p>8 sets of chromosomes (A)</p> Signup and view all the answers

What is the main consequence of nondisjunction during cell division?

<p>Gametes may have missing or extra chromosomes. (C)</p> Signup and view all the answers

Which of the following conditions is caused by nondisjunction of chromosome 21?

<p>Down Syndrome (C)</p> Signup and view all the answers

What distinguishes 'Triplo-X' syndrome from other chromosomal conditions?

<p>It is characterized by having three X chromosomes. (C)</p> Signup and view all the answers

Which of the following describes the typical sex chromosome configuration for males?

<p>XY (D)</p> Signup and view all the answers

How do polyploidy cells differ from diploid cells?

<p>Polyploidy cells have more than two sets of chromosomes. (B)</p> Signup and view all the answers

What is a common characteristic of XXX females?

<p>Menstrual irregularities. (D)</p> Signup and view all the answers

Which statement about Y chromosomes is correct?

<p>They may terminate development in utero. (C)</p> Signup and view all the answers

Which of the following statements about Cri du chat syndrome is accurate?

<p>It leads to children who cry like cats. (B)</p> Signup and view all the answers

What is the main consequence of gene duplication in evolution?

<p>One gene can mutate without disrupting normal functions. (B)</p> Signup and view all the answers

What type of genetic change is illustrated by chronic myelogenous leukemia?

<p>Translocation between nonhomologous chromosomes. (B)</p> Signup and view all the answers

What is the result of meiosis in human males?

<p>Four functional sperm cells. (C)</p> Signup and view all the answers

How does the reproductive behavior of a species (monogamous vs. promiscuous) affect sperm production?

<p>Promiscuous species tend to produce more sperm, including some dysfunctional types. (C)</p> Signup and view all the answers

What happens when a translocation event involves a gene?

<p>The gene can become nonfunctional if broken during the process. (A)</p> Signup and view all the answers

Which of the following statements regarding polar bodies is true?

<p>They are typically wasted cells formed during oogenesis. (D)</p> Signup and view all the answers

Which genetic condition is linked to repeating of a CGG sequence?

<p>Fragile X syndrome. (B)</p> Signup and view all the answers

Flashcards

Homologous Chromosomes

Pairs of chromosomes with similar genes, one inherited from each parent.

Crossing Over

The exchange of DNA segments between homologous chromosomes.

Metaphase I

Homologous chromosomes line up at the cell's center.

Anaphase I

Homologous chromosomes are pulled apart to opposite poles.

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Meiosis Outcomes

Produces four haploid cells, each genetically unique, from one diploid cell.

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Prophase II

Preparation for the second division of meiosis, similar to mitosis prophase.

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Metaphase II

Chromosomes line up in the middle of the cells again.

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Anaphase II

Sister chromatids are pulled apart to opposite poles.

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Sexual Reproduction

A reproductive process requiring two parents, each contributing genetic material to produce offspring with unique combinations of traits.

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Asexual Reproduction

A reproductive process that creates identical offspring from a single parent, without combining genetic material.

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Genetic Diversity

The variety of different genetic traits within a population or species.

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Cost of Sexual Reproduction

Energy expenditure required to find and attract a mate.

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Chromosome

A linear strand of DNA containing multiple genes.

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Conjugation

A process where two bacteria exchange genetic material, increasing genetic diversity, but not reproduction.

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Genetic Diversity Benefit

Sexual reproduction creates unique combinations of traits that can increase an organism's ability to adapt and survive. Asexual reproduction relies on mutations for similar variation.

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Meiosis

The type of cell division that produces unique sex cells, gametes

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Diploid Cell

A cell containing two sets of chromosomes (one from each parent).

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Haploid Cell

A cell containing one set of chromosomes.

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Homologous Pair

Matching pairs of chromosomes with the same genes, potentially different alleles.

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Autosome

A chromosome that is not a sex chromosome.

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Sex Chromosome

A chromosome involved in determining sex (e.g., X and Y chromosomes).

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Karyotype

A visual representation of an organism's chromosomes.

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Ploidy

The number of sets of chromosomes in a cell.

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Allele

Different variations of a gene.

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DNA Exchange

Homologous chromosomes swap DNA segments during meiosis, creating unique combinations.

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Fertilization Chance

The probability of a specific sperm and egg meeting is extremely low.

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Meiosis vs. Mitosis

Meiosis produces unique cells (gametes), while mitosis produces identical cells.

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Germ Cells

Cells that undergo meiosis to produce gametes (sex cells).

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Homologous Chromosomes

Chromosome pairs with the same genes, one inherited from each parent.

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Polyploidy

Having more than two sets of chromosomes, often in plants.

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Gametes

Reproductive cells (sperm and egg) that carry half the number of chromosomes.

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Mitosis Outcome

Produces two identical diploid cells from one diploid cell.

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Polyploidy

Cells with more than a diploid set of chromosomes.

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Nondisjunction

The failure of a pair of homologous chromosomes to split during meiosis.

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Trisomy 21

A condition resulting from nondisjunction of chromosome 21, often causing Down syndrome.

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Triplo-X Syndrome

Females with an extra X chromosome (XXX).

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Klinefelter Syndrome

Males with an extra X chromosome (XXY).

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Jacobs Syndrome

Males with an extra Y chromosome (XYY).

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Turner Syndrome

Females with one X chromosome (XO).

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Diploid/Triploid/Tetraploid etc.

Triploid means 3 sets of chromosomes and tetraploid means 4 sets, etc. This refers to ploidy, the number of chromosome sets in a cell.

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Chromosome Deletion

Loss of one or more genes on a chromosome

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Cri du Chat Syndrome

Genetic disorder caused by a chromosome deletion, resulting in unique cat-like cry and developmental delays

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Chromosome Duplication

Extra copies of a gene segment/s resulting in redundancy

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Fragile X Syndrome

Genetic disorder caused by repeated CGG sequences on the X chromosome, leading to varying degrees of mental retardation.

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Chromosome Translocation

Exchange of DNA segments between non-homologous chromosomes

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Gametes

Reproductive cells (sperm and egg) containing half the number of chromosomes of a normal cell

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Monogamous Species Sperm

Fewer viable sperm are produced per mating event

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Promiscuous Species Sperm

More sperm are produced, some are non-functional

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Study Notes

Sexual Reproduction and Meiosis

  • Sexual reproduction requires two parents, each producing sperm or ova (egg)
  • Asexual reproduction is simpler, producing identical organisms (except for mutations). It occurs in prokaryotes, unicellular eukaryotes, and some multicellular eukaryotes.
  • Conjugation, where bacteria exchange genes, is a precursor to sexual reproduction, boosting genetic diversity but not resulting in reproduction.
  • Sexual reproduction has costs, such as the energy spent attracting mates (e.g., frogs' calls, bird dances).
  • Despite costs, sexual reproduction has benefits, existing for 1.5 billion years and being crucial for most multicellular eukaryotic organisms.
  • Sexual reproduction increases genetic diversity.
  • Asexual organisms rely on mutations for diversity.
  • Sexual organisms mix DNA, creating unique genomes.

Chromosomes

  • A chromosome is a linear strand of DNA with multiple genes.
  • The number of chromosomes in a cell's nucleus varies between species.
  • Ploidy describes the number of complete chromosome sets a cell contains.
  • Most eukaryotic cells are diploid (two sets of chromosomes).
  • Sperm and egg cells are haploid (one set of chromosomes).
  • Humans have 23 pairs of chromosomes (one set from each parent).

Diploid Cells

  • In diploid cells, chromosomes exist as homologous pairs.
  • Homologous chromosomes share the same genes.
  • Gene variations within homologous chromosomes are called alleles.
  • These variations result in different traits (e.g., eye color).

Karyotype

  • A karyotype visually displays the chromosomes of an organism.
  • Most chromosomes are numbered autosomes.
  • The last pair are sex chromosomes (e.g., X and Y) determining sex identity.

Meiosis

  • Meiosis is a preparatory process for sexual reproduction.
  • Meiosis splits DNA from one cell, producing four haploid cells (gametes).
  • Female gametes are ova (egg), and male gametes are sperm.
  • After the initial cell division in meiosis, each resulting cell undergoes another division.
  • Fertilization unites egg and sperm, creating a zygote that develops into an adult organism.
  • Somatic cells, concerned with body growth and replacement, do not participate in meiosis.
  • Specialized germ cells are the site of meiosis.

Meiosis as a Tool for Genetic Diversity

  • Meiosis reduces chromosomes from diploid to haploid.
  • Meiosis re-combines alleles within homologous pairs, increasing diversity.
  • Mitosis (used in regular cell division) produces two identical diploid cells.

Phases of Meiosis

  • Meiosis begins like mitosis with interphase (DNA replication). Proteins for DNA replication are manufactured during the G2 phase. Two divisions of cells follow.
  • Meiosis I involves the separation of homologous chromosomes.
    • Prophase I: Long, complex events including crossing over between homologous chromosomes.
    • Metaphase I: Homologous chromosomes line up on the cell's equator.
    • Anaphase I: Homologous chromosomes separate.
    • Telophase I and Cytokinesis: Two haploid cells form .
  • Meiosis II involves the separation of sister chromatids, just like mitosis.
    • Prophase II: Spindle fibers form and attach to duplicated chromosomes.
    • Metaphase II: Sister chromatids align on the cell's equator.
    • Anaphase II: Sister chromatids separate.
    • Telophase II and Cytokinesis: Four haploid cells form.

Crossing Over

  • Crossing over occurs in Prophase I of meiosis.
  • Homologous chromosomes exchange segments of DNA, increasing genetic diversity.
  • This DNA exchange between homologous chromosomes creates new combinations of alleles.

Random Fertilization

  • Fertilization involves one sperm cell uniting with one egg cell.
  • Sperm and egg cells are diverse and random.
  • The combination produced is unique.
  • The chance of any particular baby being born is very low, yet the chance that a baby is capable of being born is high.

Mitosis and Meiosis Comparison

  • Mitosis occurs in somatic cells, while meiosis occurs in germ cells.
  • Mitosis produces identical diploid daughter cells, while meiosis produces unique haploid daughter cells.
  • Mitosis involves one cell division and replicates DNA once, whereas meiosis involves two cell divisions and replicates DNA once.
  • Mitosis maintains chromosome numbers and doesn't involve homologous chromosome pairing.

Polyploidy

  • Polyploidy refers to cells having more than two sets of chromosomes.
  • Polyploidy occurs when homologous chromosomes fail to separate during cell division.
  • Animals have less success with more than two sets of DNA, but angiosperms frequently are polyploidy.

Nondisjunction

  • Nondisjunction is the failure of chromosomes to properly separate during meiosis.
  • Results in gametes either missing or having extra chromosomes.
  • Most embryos with abnormal numbers of chromosomes cease developing before birth
  • Most extra chromosomes have fewer problems than missing chromosomes.
  • Trisomy 21 (Down’s syndrome) is one example, caused by an extra chromosome 21.

Extra or Missing Sex Chromosomes

  • Abnormal numbers of sex chromosomes can result in various syndromes (e.g., Klinefelter syndrome, Turner syndrome, Jacobs syndrome).

Small-Scale Chromosome Abnormalities

  • Deletions remove chromosome segments.
  • Duplications repeat segments.
  • Fragile X syndrome is one example of a segment repetition disorder.
  • Abnormal chromosomal events may affect a single gene.

Translocation

  • Translocation is the switching of segments between non-homologous chromosomes.
  • Can create problems for genetic function, but sometimes no problems are observed.
  • Chronic myelogenous leukemia is one condition connected to chromosomal translocation.

Gametes

  • The end result of meiosis is four gametes (sperm or egg).
  • In species where copulation is frequent, fewer sperm are needed compared with those in promiscuous species.
  • Females put a larger investment into producing fewer but more functional gametes.

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Sexual Reproduction and Meiosis Chapter 9 PDF

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Explore the intricacies of sexual reproduction and meiosis in this quiz. Understand the differences between sexual and asexual reproduction, the role of chromosomes, and how genetic diversity is achieved. This quiz is perfect for biology students looking to solidify their knowledge on reproductive methods and genetic principles.

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