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Questions and Answers
Which of the following is an advantage of external fertilization?
Which of the following is an advantage of external fertilization?
Internal fertilization leads to higher survival rates for offspring due to parental care.
Internal fertilization leads to higher survival rates for offspring due to parental care.
True
What is the primary purpose of therapeutic cloning?
What is the primary purpose of therapeutic cloning?
What is the process through which male gametes are transferred to female plant structures?
What is the process through which male gametes are transferred to female plant structures?
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The protective case that carries sperm cells in plants is called _____ grains.
The protective case that carries sperm cells in plants is called _____ grains.
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Stem cells from specific body tissues can become any type of cell in the human body.
Stem cells from specific body tissues can become any type of cell in the human body.
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What is the process by which a haploid sperm cell and a haploid egg cell form a diploid zygote?
What is the process by which a haploid sperm cell and a haploid egg cell form a diploid zygote?
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Match the type of fertilization with its characteristic:
Match the type of fertilization with its characteristic:
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Aquatic animals typically reproduce through __________ fertilization.
Aquatic animals typically reproduce through __________ fertilization.
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Which of the following organisms commonly use internal fertilization?
Which of the following organisms commonly use internal fertilization?
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Match the following cloning types with their descriptions:
Match the following cloning types with their descriptions:
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Zygotes formed from external fertilization are protected from predators.
Zygotes formed from external fertilization are protected from predators.
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What happens to the zygote after fertilization in plants?
What happens to the zygote after fertilization in plants?
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What must occur for sexual reproduction to take place in most species?
What must occur for sexual reproduction to take place in most species?
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All sexually reproducing species require two separate parents.
All sexually reproducing species require two separate parents.
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What is fragmentation in the context of reproduction?
What is fragmentation in the context of reproduction?
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What is the correct order of the phases of mitosis?
What is the correct order of the phases of mitosis?
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Cytokinesis occurs before the phases of mitosis.
Cytokinesis occurs before the phases of mitosis.
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What are gametes?
What are gametes?
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In meiosis, sister chromatids separate during meiosis ____.
In meiosis, sister chromatids separate during meiosis ____.
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Match the following terms with their definitions:
Match the following terms with their definitions:
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What is one benefit of genetic diversity?
What is one benefit of genetic diversity?
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Sexual reproduction requires only one parent.
Sexual reproduction requires only one parent.
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What is the total number of chromosomes in human body cells?
What is the total number of chromosomes in human body cells?
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What is the diploid number of chromosomes in human body cells?
What is the diploid number of chromosomes in human body cells?
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Gametes are diploid cells.
Gametes are diploid cells.
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What process produces haploid gametes from diploid cells?
What process produces haploid gametes from diploid cells?
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Meiosis produces _____ haploid cells from one diploid cell.
Meiosis produces _____ haploid cells from one diploid cell.
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Match the following terms with their definitions:
Match the following terms with their definitions:
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During which phase of meiosis is crossing over most likely to occur?
During which phase of meiosis is crossing over most likely to occur?
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Each gamete contains 46 chromosomes.
Each gamete contains 46 chromosomes.
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What are homologous chromosomes?
What are homologous chromosomes?
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What is the primary outcome of crossing over during meiosis?
What is the primary outcome of crossing over during meiosis?
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Independent assortment during meiosis leads to a maximum of 2 million combinations of chromosomes in human gametes.
Independent assortment during meiosis leads to a maximum of 2 million combinations of chromosomes in human gametes.
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What is the term for a fertilized egg?
What is the term for a fertilized egg?
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In females, _________ are the end products of meiosis with unequal division of cytoplasm.
In females, _________ are the end products of meiosis with unequal division of cytoplasm.
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Match the following terms related to chromosomal changes with their descriptions:
Match the following terms related to chromosomal changes with their descriptions:
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How many cells does meiosis produce in males?
How many cells does meiosis produce in males?
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Mutations can only occur during meiosis, not during any exposure to environmental factors.
Mutations can only occur during meiosis, not during any exposure to environmental factors.
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What do homologous chromosomes refer to?
What do homologous chromosomes refer to?
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Study Notes
Therapeutic Cloning
- Purpose of therapeutic cloning is to address and correct health problems
- Stem cells are crucial for therapeutic cloning
- Stem cells from human embryos can become any type of human cell (200+ types)
- Stem cells from specific body tissues can only become a restricted number of cell types
- Stem cells can be used to replace damaged cells caused by injuries or diseases like diabetes, spinal cord injuries, and Parkinson's disease
- Therapeutic cloning is controversial due to the use of embryos, which are destroyed during stem cell extraction
Sexual Reproduction
- Male gametes (sperm) must fertilize female gametes (egg) for sexual reproduction to occur
- Meiosis and the fusion of sperm and egg cells produce unique DNA in individuals, except identical twins
- External fertilization is common in aquatic animals
- Internal fertilization is dominant in land animals
- After fertilization, zygote and embryo development occurs through mitosis and cell differentiation
- Asexual reproduction requires only one parent and can occur in favorable environments
- Sexual reproduction requires two parents for gamete fusion and fertilization
- Sexually reproducing species need to mate with individuals of their own species for survival
- Sexual reproduction involves three stages: mating, fertilization, and development
- Mating facilitates the meeting of gametes (sperm and egg) at the same time and location
- Fertilization is the union of a haploid sperm cell and a haploid egg cell to produce a diploid zygote
External Fertilization
- Occurs when sperm and egg cells combine outside the parent's bodies
- Common in aquatic animals and plants in moist environments
- Advantages: Minimal energy required for mate finding, large offspring production, offspring dispersal minimizes competition with parents, genetic variation is maintained
- Disadvantages: Low survival rate of gametes outside the body, vulnerability of zygotes and embryos, limited parental care, low adult survival rates
Internal Fertilization
- Occurs when sperm and egg cells combine within the female parent's body
- Common in birds, mammals, and flowering plants
- Advantages: Increased offspring survival due to embryo protection and parental care
- Disadvantages: Higher energy expenditure for mate finding, lower zygote production compared to external fertilization
Pollination
- Process of internal fertilization in most plants
- Involves the transfer of male gametes in pollen grains (sperm-carrying structures) to ovules (egg-containing structures)
- After pollen lands, a pollen tube forms, delivering sperm to the egg cells
- Fertilization leads to embryo development within a seed, nourished by stored food
- The seed's outer coating protects the developing embryo
Phases of Mitosis
- Mitosis has four phases: prophase, metaphase, anaphase, and telophase (PMAT)
- After PMAT, cytokinesis occurs, dividing the parent cell into two daughter cells
Meiosis
- Meiosis produces specialized cells called gametes
- Gametes have half the number of chromosomes compared to body cells
- Meiosis involves two cell divisions: meiosis I and meiosis II
- In meiosis I, homologous chromosomes (matching chromosome pairs) separate
- In meiosis II, sister chromatids separate
- Meiosis shuffles genetic information, resulting in variation in gametes
Variation and Genetic Diversity
- Sexual reproduction produces genetically diverse offspring unlike asexual reproduction
- Genetic diversity is the result of random shuffling and sorting of DNA during sexual reproduction
- Genetic diversity equips organisms with better chances to adapt to environmental changes
Gametes and Body Cells
- All human body cells (somatic cells) have 46 chromosomes arranged in 23 pairs
- One chromosome from each pair is inherited from the mother, the other from the father
- Diploid cells have pairs of chromosomes (2 sets)
- The diploid number in humans is 46 (2 x 23 chromosomes)
- Gametes have only one set of chromosomes (23 chromosomes), making them haploid
Gamete Haploidy
- Haploid gametes with 23 chromosomes are required for fertilization to produce a diploid zygote with 46 chromosomes
- Meiosis ensures that each gamete is haploid
- Random division of chromosome pairs during meiosis creates millions of possible chromosome combinations in each gamete
- Fertilization combines chromosomes from both parents, increasing genetic diversity
Meiosis Process
- Each chromosome in a cell is duplicated once during meiosis, followed by two cell divisions
- The first division is meiosis I, similar to mitosis, but homologous chromosomes separate
- Meiosis I starts with a diploid cell and ends with two diploid cells
- Meiosis II starts with two diploid cells and ends with four haploid cells
- Overall, meiosis starts with one diploid cell and produces four haploid cells
Crossing Over
- Occurs between homologous chromosomes in meiosis I
- Non-sister chromatids exchange DNA segments, creating infinite genetic possibilities in gametes
Independent Assortment
- Homologous chromosome pairs separate at the equator and move to opposite poles of the cell in meiosis I
- Each chromosome pair has two possible sorting outcomes, leading to over 8 million combinations for 23 pairs
- Fertilization can produce over 70 trillion different zygotes due to the combination of sperm and egg chromosomes
Gamete Formation in Males and Females
- In males, meiosis I produces two cells, followed by meiosis II resulting in four mature sperm cells
- In females, meiosis I produces two egg cells with unequal cytoplasm and organelles
- Meiosis II results in three disintegrating cells, leaving one large egg cell for fertilization
Chromosome Mutations in Meiosis
- Small gene mutations may have no effect or cause disease
- Large-scale DNA and gene rearrangements (loss, duplication, or movement of chromosome pieces) often occur during meiosis
- These changes affect genes and the corresponding proteins
- Chromosome mutations can also occur due to exposure to mutagens like radiation or chemicals
- Whole chromosome mutations can arise in meiosis I (homologous chromosome separation failure) or meiosis II (sister chromatid separation failure)
- Resulting gametes may have an extra copy or lack a copy of a chromosome
- Many chromosome mutations are not passed on as offspring may fail to develop or reach reproductive age
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Description
Explore the essential concepts of therapeutic cloning and sexual reproduction in this quiz. Understand the role of stem cells in health solutions and the mechanisms of gamete fertilization. Ideal for students studying biology topics related to human development and reproductive processes.
