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Questions and Answers
What is formed around each group of chromatids during telophase?
What is formed around each group of chromatids during telophase?
Nuclear envelope
During telophase, spindle fibers remain attached to the chromosomes.
During telophase, spindle fibers remain attached to the chromosomes.
False (B)
The process of dividing the cytoplasm is called ______.
The process of dividing the cytoplasm is called ______.
cytokinesis
Which of the following occurs during telophase?
Which of the following occurs during telophase?
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During prometaphase, the nuclear envelope remains intact.
During prometaphase, the nuclear envelope remains intact.
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Match the following events with the correct stage of mitosis they occur in:
Match the following events with the correct stage of mitosis they occur in:
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Which stage of mitosis is characterized by the alignment of chromosomes at the metaphase plate?
Which stage of mitosis is characterized by the alignment of chromosomes at the metaphase plate?
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What is the result of cytokinesis?
What is the result of cytokinesis?
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Plant cells use a contractile ring to divide the cytoplasm.
Plant cells use a contractile ring to divide the cytoplasm.
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What is the primary function of the spindle fibers during anaphase?
What is the primary function of the spindle fibers during anaphase?
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During ______, chromosomes condense and become visible.
During ______, chromosomes condense and become visible.
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The spindle fibers attach to the ______ on each sister chromatid during prometaphase.
The spindle fibers attach to the ______ on each sister chromatid during prometaphase.
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What happens to the chromosomes after they decondense in telophase?
What happens to the chromosomes after they decondense in telophase?
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Match the stages of mitosis with their key events:
Match the stages of mitosis with their key events:
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Which stage of mitosis involves the separation of sister chromatids?
Which stage of mitosis involves the separation of sister chromatids?
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In prometaphase, chromosomes line up at the metaphase plate.
In prometaphase, chromosomes line up at the metaphase plate.
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What is the primary event that occurs during interphase?
What is the primary event that occurs during interphase?
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Match the following stages of mitosis with their key events:
Match the following stages of mitosis with their key events:
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Centrioles are present in both plant and animal cells.
Centrioles are present in both plant and animal cells.
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What happens to the nucleolus during prophase?
What happens to the nucleolus during prophase?
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What are the two major events that occur during interphase?
What are the two major events that occur during interphase?
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Flashcards
Prometaphase
Prometaphase
The stage where the nuclear envelope breaks down and spindle fibers attach to kinetochores of chromosomes.
Metaphase
Metaphase
Chromosomes align at the metaphase plate with sister chromatids facing opposite poles.
Anaphase
Anaphase
Sister chromatids are pulled apart, moving toward opposite poles, forming a characteristic V shape.
Spindle fibers
Spindle fibers
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Kinetochores
Kinetochores
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Telophase
Telophase
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Cytokinesis
Cytokinesis
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Daughter cells
Daughter cells
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Chromatid
Chromatid
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Cell plate
Cell plate
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Cleavage furrow
Cleavage furrow
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Diploid (2n)
Diploid (2n)
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Sex determination
Sex determination
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Homogametic
Homogametic
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Heterogametic
Heterogametic
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Stages of mitosis
Stages of mitosis
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Prophase
Prophase
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Study Notes
Genetics: From Genes to Genomes
- This is a textbook, specifically the fourth edition, covering genetics.
- Authors are Leland H. Hartwell, Leroy Hood, Michael L. Goldberg, Ann E. Reynolds, and Lee M. Silver.
- Notes were prepared by Mary A. Bedell at the University of Georgia.
Basic Principles: How Traits Are Transmitted
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Chromosome Theory of Inheritance
- Chromosomes are cellular structures that transmit genetic information.
- Breeding experiments and microscopy supported the chromosome theory of inheritance.
- Proper development relies on accurately passing one's genes and maintaining the chromosome number.
- The abstract idea of a gene was transformed into a physical reality by the chromosome theory.
- Genes consist of DNA.
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Mitosis
- A process that produces two daughter cells with the same number and type of chromosomes/genes as the parent cell.
- The resulting daughter cells are identical to each other and the parent cell.
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Meiosis
- A process that produces gametes (egg and sperm cells).
- Gametes have half the number of chromosomes compared to the parent cell.
- For example, in humans:
- Parent cell has 46 chromosomes.
- Gamete (sperm or egg) has 23 chromosomes.
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Diploid versus Haploid
- Most body cells are diploid (chromosomes in pairs: one copy from each parent).
- Meiosis converts diploid cells into haploid gametes.
- In humans, 2n = 46 (diploid) and n = 23 (haploid).
- Diploid = double set of chromosomes
- Haploid = one set of chromosomes
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Fertilization
- The union of haploid gametes (egg and sperm) to produce a diploid zygote.
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Metaphase Chromosome Classification
- Metaphase chromosomes can be categorized by centromere position.
- This classification includes metacentric and acrocentric chromosomes.
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Human Karyotype
- A visual display of an organism's chromosomes.
- Humans have 22 homologous pairs of autosomes and two sex chromosomes.
- Photos of metaphase chromosomes are used to create a karyotype.
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X and Y Chromosomes
- Determine sex in humans.
- Children inherit an X chromosome from their mother and either an X or a Y chromosome from their father.
- This results in a 1:1 ratio of females to males.
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Mechanisms of Sex Determination
- Sex determination varies between species.
- Examples include XY (humans), ZW (birds), XO (some insects), and others.
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Mitosis Stages
- Interphase: DNA replication and transcription occurs.
- Prophase: Chromosome condensation.
- Prometaphase: Spindle formation and attachment to chromatids.
- Metaphase: Chromosomes align at the metaphase plate.
- Anaphase: Sister chromatids separate.
- Telophase: Chromosomes decondense and nuclei reform.
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Cytokinesis
- The cytoplasm divides, forming two daughter cells.
- Animals have a contractile ring, while plants form a cell plate.
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Meiosis
- Two rounds of cell division (Meiosis I and Meiosis II) produce four haploid daughter cells.
- DNA replication occurs only once prior to meiosis.
- During meiosis I, homologous chromosomes pair up, exchange segments (crossing over), and then separate.
- During meiosis II, sister chromatids separate.
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Meiosis I and II
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Prophase I - chromosomes condense, homologous chromosomes pair up, crossing over occurs between homologous chromosomes.
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Metaphase I - chromosomes line up in homologous pairs at the center of the cell. Spindle fibers attach to centromeres.
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Anaphase I - Homologous chromosomes separate and migrate to opposite poles. Sister chromatids remain joined.
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Telophase I and Cytokinesis - chromosomes reach the poles, cytoplasm divides, two haploid daughter cells form.
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Prophase II- chromosomes condense again. Spindle forms.
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Metaphase II- chromosomes line up at the equator of each cell. Spindle fibers attach to centromeres.
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Anaphase II- Sister chromatids separate and move to opposite poles.
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Telophase II and Cytokinesis - chromosomes reach poles, cytoplasm divides, four haploid daughter cells form.
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Genetic Diversity
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Meiosis produces genetic diversity through
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Crossing-over : exchange of genetic material between homologous chromosomes during prophase I, which creates new combinations of alleles.
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Independent Assortment : random alignment of homologous chromosomes during metaphase I and sister chromatids during metaphase II determines which combination of alleles each gamete receives.
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Gametogenesis in sexually reproducing animals
- Formation of gametes
- Specialized process: before and after meiosis, in different types of animals variations in the general process.
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Germ cells
- Precursors to gametes.
- The set aside from somatic cells during embryogenesis, incorporated in reproductive organs.
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Nondisjunction
- Errors in chromosome segregation, leading to abnormal chromosome numbers (e.g., Down Syndrome).
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Hybrid Sterility
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Hybrids between species (e.g., mule) are often sterile because chromosomes cannot properly pair up.
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Description
Test your knowledge on the fundamental concepts of genetics covered in 'Genetics: From Genes to Genomes'. This quiz will explore the chromosome theory of inheritance, mitosis, and the transmission of traits. Challenge yourself and see how well you understand these essential topics in genetics.
