Random alignment of homologous pairs during this phase is the basis of independent assortment.
Awesome! Diagram 3 is the basis of independent assortment.
HINT FOR NEXT TIME: You’re looking for metaphase 1, when homologous pairs are lined up in the middle of the cell.
Crossing over is happening, leading to recombinant chromosomes.
Good work! Crossing over happens during prophase 1
HINT FOR NEXT TIME: You’re looking for prophase 1. Find the phase when homologous pairs are paired up (but not aligned at the center of the cell)
DNA replication/ Chromosome Duplication
Yes! “1” is interphase 1, which is when DNA replication happens.
HINT FOR NEXT TIME: It happens during interphase 1, right at the start of meiosis.
Homologous pairs are pulled apart
Way to go! Homologous pairs are pulled apart during anaphase 1, represented by “4.”
HINT FOR NEXT TIME: Homologous pairs are pulled apart during anaphase 1. This only happens after homologous pairs are pulled to the middle of the cell.
Two haploid nuclei form, and the first cytokinesis starts
Very nice! Two haploid nuclei form in telophase 1, shown at “5.”
HINT FOR NEXT TIME: You’re looking for telophase 1. Look for two nuclei inside one daughter cell.
Doubled chromosomes condense in a haploid cell (after cytokinesis 1)
Thumbs up! Doubled chromosomes condense in prophase 2, which is diagram 8.
HINT FOR NEXT TIME: Look for two similar daughter cells. Each daughter cell is haploid, with half the number of chromosomes that the cell had during Meiosis I.
Doubled chromosomes condense in haploid daughter cells.
Terrific. Doubled chromosomes in haploid cells condense during prophase 2.
HINT FOR NEXT TIME: You’re looking for prophase 2. Find daughter cells with half the chromosomes as the cell had in meiosis 1.
Doubled chromosomes consisting of two sister chromatids are aligned in the middle of the cells.
Superb! That’s what happens during metaphase 2.
HINT FOR NEXT TIME: You’re looking for metaphase 2, which i during meiosis II. Where are doubled chromosomes in the middle of the cell?
Sister chromatids are being pulled apart.
Outstanding! That’s what happens during anaphase 2.
HINT FOR NEXT TIME: You’re looking for anaphase two which is in meiosis II.
New haploid nuclei are forming around single chromosomes.
Outstanding! You’ve identified what happens during telophase 2.
HINT FOR NEXT TIME: Look for two daughter cells, each with two nuclei.
Haploid cells with single chromosomes
Nice! The cells at “13” as haploid cell with single chromosomes.
HINT FOR NEXT TIME: Find cells that have a pair of single (as opposed to doubled) chromosomes.
DNA replication. Single chromosomes become sister chromatids.
Yes! “1” is interphase 1, which is when DNA replication occurs.
HINT FOR NEXT TIME: Meiosis begins just like mitosis, with DNA replication. That would have to be happening where?
[q json=”true” hotspot_user_interaction=”label_prompt” dataset_id=”Meiosis Click-on dataset|b8eb01403a6c7″ question_number=”2″ show_hotspots=”” unit=”5.Heredity” topic=”5.1-2.Meiosis_and_Genetic_Diversity”] The life cycle of a sexually reproducing species.
491.12805950095964 x 499
Process that creates haploid gametes.
Nice! “3” represents meiosis.
HINT FOR NEXT TIME: Meiosis is the process by which haploid gametes (sperm and egg cells) are made. These cells are shown at 4a and 4b.
Haploid female gamete
Good work. “4a” represents the haploid ovum, or female gamete.
HINT FOR NEXT TIME: Trace the line from the mother (at 1a) up to the sex cell that she creates.
Haploid male gamete
Exactly: The sperm cell at “4b” is the haploid male gamete.
HINT FOR NEXT TIME: Find the father, and trace the line up to the sperm cell he creates.
Restores chromosome number from haploid to diploid.
Excellent. Fertilization (at 5) restores the diploid chromosome number.
HINT FOR NEXT TIME: You’re looking for fertilization, the process through which sperm and egg cells combine to create a fertilized egg.
Diploid zygote
Awesome. “6” is the diploid zygote.
HINT FOR NEXT TIME: Fertilization leads to a diploid zygote. That zygote develops into an adult.
Mitosis and development
Yes! “7” represents mitosis and development.
HINT FOR NEXT TIME: Find the processes by which a fertilized egg becomes an adult.
Organ that creates male gametes.
Way to go. The testes (2b) create the male gamete.
HINT FOR NEXT TIME: These are the structures in a male that create sperm.
Organ that creates female gametes.
Very nice. The ovaries (2a) create the female gamete.
HINT FOR NEXT TIME: Find a structure between the mother and the egg cell.
[q json=”true” xx=”2″ hotspot_user_interaction=”label_prompt” dataset_id=”Meiosis Click-on dataset|b8b6e8b62cec7″ question_number=”3″ show_hotspots=”” unit=”5.Heredity” topic=”5.1-2.Meiosis_and_Genetic_Diversity”] Meiosis: The Big Picture
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Arrow(s) representing DNA replication
Yes! “1” represents DNA replication.
HINT FOR NEXT TIME: Find where single chromosomes change into doubled chromosomes, consisting of two sister chromatids.
Arrow(s) representing separation of homologous pairs.
Way to go! “2” represents meiosis I, which separates homologous chromosomes.
HINT FOR NEXT TIME: Homologous pairs are separated during the first cell division (Meiosis I).
Arrow(s) representing separation of sister chromatids.
Very nice. “3” represents meiosis II, which separates sister chromatids.
HINT FOR NEXT TIME: The doubled chromosomes made of two connected sister chromatids look like an “X.” Find cells at the end of meiosis without these doubled chromosomes, and work back from there.
Diploid cell(s) with doubled chromosomes.
Terrific: The cell between “1” and “2” is diploid, with doubled chromosomes.
HINT FOR NEXT TIME: The cells are diploid when each chromosome has a homologous partner. That’s before the first cell division.
Haploid cells with doubled chromosomes
Superb! The cells between “2” and “3” are haploid, but with doubled chromosomes.
HINT FOR NEXT TIME: Count the number of chromosomes in the germ cell on the far left. Now, follow the arrows and find the first cell in which the chromosome number is half of that.
Haploid cells with single chromosomes, ready to be gametes
Outstanding! After meiosis II (at “3”) the cells are haploid, with single chromosomes.
HINT FOR NEXT TIME: Look for these cells after the second cell division.
[q json=”true” hotspot_user_interaction=”label_prompt” dataset_id=”Meiosis Click-on dataset|a6268b6801a5c” question_number=”4″ show_hotspots=”” unit=”5.Heredity” topic=”5.1-2.Meiosis_and_Genetic_Diversity”] Comparison of Meiosis and Mitosis
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Parent cell in mitosis
Awesome! That’s the parent cell.
HINT FOR NEXT TIME: In mitosis, the daughter cells have the same chromosome number as the parent cell.
Diploid daughter cells that result from mitosis
Excellent!
HINT FOR NEXT TIME: In mitosis, the daughter cells have the same number of chromosomes as the parent cell.
Germ cell for meiosis.
Great job!
HINT FOR NEXT TIME: Look for a diploid cell with single (non-doubled) chromosomes that starts meiosis. Remember the meiosis has two cell divisions.
Haploid daughter cells with doubled chromosomes.
Good work
HINT FOR NEXT TIME: Look for cells that result from the first meiotic cell division.
Haploid daughter cells with single chromosomes, ready to become gametes.
Fantastic!
HINT FOR NEXT TIME: You’re looking for the cells that result from the second meiotic division.
Meiotic cell immediately after DNA replication
Excellent!
HINT FOR NEXT TIME: Meiosis has two cell divisions, and it starts with DNA replication. The replicated DNA is in doubled chromosomes, which look like an “X.”
[q json=”true” hotspot_user_interaction=”label_prompt” dataset_id=”Meiosis Click-on dataset|dab071786efff” question_number=”5″ show_hotspots=”” unit=”5.Heredity” topic=”5.6.Chromosomal_Inheritance”] Chromosomal sex determination in humans
591.063769005848 x 347
Male germ cell
Yes. The male germ cell is at “1.”
HINT FOR NEXT TIME: Human male germ cells have 44 autosomes and an X and Y chromosome.
Female germ cell
Way to go!
HINT FOR NEXT TIME: The human female germ cell has 44 autosomes and two X chromosomes.
A gamete from the mother that will produce a female offspring.
Thumbs up!
HINT FOR NEXT TIME: Look for haploid egg cell that comes from the female germ cell. This egg cell will have 22 autosomes and an X chromosome.
A gamete that will produce male offspring
Terrific!
HINT FOR NEXT TIME: A human male producing gamete will have 22 autosomes and a Y chromosome.
A sperm cell that will produce female offspring
Outstanding.
HINT FOR NEXT TIME: Look for a haploid cell from the father that has 22 autosomes and an X chromosome.
A female zygote
Nice going!
HINT FOR NEXT TIME: Look for a cell that results from the fusion of a sperm and an egg cell. That fertilized egg cell (a zygote) will have 44 autosomes and two X chromosomes.
A male zygote
Nice job!
HINT FOR NEXT TIME: Look for a cell that results from the fusion of a sperm and an egg cell. That fertilized egg cell (a zygote) will have 44 autosomes, one X chromosome, and one Y chromosome.
