1. Introduction
In the previous tutorial, we talked about the basics of meiosis. In this tutorial, we’ll look at the life cycle of sexually reproducing organisms, and how the creation of haploid gametes involves two cell divisions.
2. Haploid cells, Diploid cells, and the Life Cycle of Sexually Reproducing Organisms
Let’s use the meiosis-related vocabulary from the last tutorial to understand the haploid and diploid moments that occur in the human life cycle. Note that with some minor variations, this same life cycle can be applied to other sexually reproducing animals. Other eukaryotes — plants, fungi, and single-celled eukaryotes also have haploid and diploid moments in their life cycles.
We’ll start at the bottom left, where you see an adult female (1a) and an adult male (1b). All of their cells, except for their gametes, are diploid.
“3” represents the process of meiosis. During meiosis, germ cells in the ovaries (2a) or testes (2b) meiotically divide in a way that reduces the chromosome number from diploid (2 sets) to haploid (one set). The results are male and female gametes: sperm (4b) or egg cells (4a).
“5” represents fertilization. The sperm fuses with the egg. This creates a fertilized egg, or zygote (6). Because the zygote has received one set of chromosomes from the egg, and one set of chromosomes from the sperm, it has two sets of chromosomes, making it diploid.
“7” represents the processes of mitotic cell division, growth, and development. The result is a reproductively mature male or female, able to produce gametes and pass his or her genes on to the next generation.
Got it? Try this quiz. Note that, by design, I’ve changed the numbering scheme in the diagram. That difficulty will improve memory.
3. Quiz: The Life Cycle of Sexually Reproducing Organisms
[qwiz qrecord_id=”sciencemusicvideosMeister1961-Life Cycle of Sexually Reproducing Organisms (v2.0)”]
[h]The life cycle of sexually reproducing organisms
[i]
[q labels = “top”]
[l]adult female
[fx] No, that’s not correct. Please try again.
[f*] Excellent!
[l]adult male
[fx] No. Please try again.
[f*] Good!
[l]fertilization
[fx] No. Please try again.
[f*] Excellent!
[l]egg
[fx] No. Please try again.
[f*] Correct!
[l]growth and development
[fx] No. Please try again.
[f*] Excellent!
[l]meiosis
[fx] No. Please try again.
[f*] Great!
[l]ovary
[fx] No. Please try again.
[f*] Correct!
[l]sperm
[fx] No. Please try again.
[f*] Great!
[l]testes
[fx] No, that’s not correct. Please try again.
[f*] Correct!
[l]zygote
[fx] No, that’s not correct. Please try again.
[f*] Good!
[q] In the diagram below, which number represents fertilization?
[c]IEk=[Qq]
[c]IE lJ[Qq]
[c]IElJSQ==[Qq]
[f]IE5vLiBSb21hbiBudW1lcmFsIEkgc2hvd3MgdGhlIHByb2Nlc3MgYnkgd2hpY2jCoCBnYW1ldGVzIGFyZSBmb3JtZWQgZnJvbSBnZXJtIGNlbGxzIGluIHRoZSBvdmFyaWVzIGFuZCB0ZXN0ZXMuIEZlcnRpbGl6YXRpb24gaXMgd2hlbiB0d28gZ2FtZXRlcyBmdXNlIHRvIGJlY29tZSBhIHp5Z290ZS4gV2hlcmUgaW4gdGhlIGRpYWdyYW0gZG8geW91IHNlZSB0d28gY2VsbHMgYmVjb21pbmcgb25lPw==[Qq]
[f]IEV4YWN0bHkuIElJIHNob3dzIGEgc3Blcm0gYW5kIGFuIGVnZyBjZWxsIGZ1c2luZyB0byBiZWNvbWUgYSB6eWdvdGUu[Qq]
[f]IE5vLiBJSUkgc2hvd3MgYSB6eWdvdGUgZ3Jvd2luZyBhbmQgZGV2ZWxvcGluZyB0byBiZWNvbWUgYW4gYWR1bHQgb3JnYW5pc20uIEZlcnRpbGl6YXRpb24gaXMgd2hlbiB0d28gZ2FtZXRlcyBmdXNlIHRvIGJlY29tZSBhIHp5Z290ZS4gV2hlcmUgaW4gdGhlIGRpYWdyYW0gZG8geW91IHNlZSB0d28gY2VsbHMgYmVjb21pbmcgb25lPw==
Cg==[Qq]
[q] In the diagram below, which number represents meiosis?
[c]IE k=[Qq]
[c]IElJ[Qq]
[c]IElJSQ==[Qq]
[f]IFllcy4gUm9tYW4gbnVtZXJhbCBJIHNob3dzIGEgc3Blcm0gYW5kIGFuIGVnZyBjZWxsIGZvcm1pbmcgZnJvbSB0aXNzdWUgaW4gdGhlIHRlc3RlcyBhbmQgb3Zhcmllcy4gVGhpcyBpcyB3aGF0IGhhcHBlbnMgaW4gbWVpb3Npcy4=[Qq]
[f]IE5vLiBJSSBpcyBzaG93aW5nIGFuIGVnZyBhbmQgYSBzcGVybSBjZWxsIGZ1c2luZyB0byBmb3JtIGEgenlnb3RlLCBhIHByb2Nlc3Mga25vd24gYXMgZmVydGlsaXphdGlvbi4gTmV4dCB0aW1lLCBjaG9vc2UgYSBwcm9jZXNzIHRoYXQgc2hvd3MgdGhlIGZvcm1hdGlvbiBvZiBlZ2cgY2VsbHMgb3Igc3Blcm0gY2VsbHMgKHdoaWNoIGlzIHdoYXQgaGFwcGVucyBkdXJpbmcgbWVpb3Npcyku[Qq]
[f]IE5vLiBJSUkgc2hvd3MgYSB6eWdvdGUgZ3Jvd2luZyBhbmQgZGV2ZWxvcGluZyB0byBiZWNvbWUgYW4gYWR1bHQgb3JnYW5pc20uIE5leHQgdGltZSwgY2hvb3NlIGEgcHJvY2VzcyB0aGF0IHNob3dzIHRoZSBmb3JtYXRpb24gb2YgZWdnIGNlbGxzIG9yIHNwZXJtIGNlbGxzICh3aGljaCBpcyB3aGF0IGhhcHBlbnMgZHVyaW5nIG1laW9zaXMpLg==
Cg==[Qq]
[q] In the diagram below, which number represents mitosis, growth, and development?
[c]IEk=[Qq]
[c]IElJ[Qq]
[c]IElJ SQ==[Qq]
[f]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[Qq]
[f]IE5vLiBJSSBpcyBzaG93aW5nIGFuIGVnZyBhbmQgYSBzcGVybSBjZWxsIGZ1c2luZyB0byBmb3JtIGEgenlnb3RlLCBhIHByb2Nlc3Mga25vd24gYXMgZmVydGlsaXphdGlvbi4gTmV4dCB0aW1lLCBsb29rIGZvciBhIHByb2Nlc3MgdGhhdCBzaG93cyBhIGNoYW5nZSBmcm9tIGEgc2luZ2xlIGNlbGwgdG8gYSBtdWx0aWNlbGx1bGFyIGFkdWx0LiBUaGlzIGNoYW5nZSB3b3VsZCBjb21lIGFib3V0IHRocm91Z2ggcmVwZWF0ZWQgcm91bmRzIG9mIG1pdG9zaXMsIGNlbGwgZ3Jvd3RoLCBhbmQgY2VsbCBkaWZmZXJlbnRpYXRpb24gYXMgdGhlIG9yZ2FuaXNtIGRldmVsb3BzLg==[Qq]
[f]IFBlcmZlY3QuIElJSSBzaG93cyBhIHp5Z290ZSBncm93aW5nIGFuZCBkZXZlbG9waW5nIHRvIGJlY29tZSBhbiBhZHVsdCBvcmdhbmlzbS4gVGhpcyBjaGFuZ2Ugd291bGQgY29tZSBhYm91dCB0aHJvdWdoIHJlcGVhdGVkIHJvdW5kcyBvZiBtaXRvc2lzLCBjZWxsIGdyb3d0aCwgYW5kIGNlbGwgZGlmZmVyZW50aWF0aW9uIGFzIHRoZSBvcmdhbmlzbSBkZXZlbG9wcy4=
Cg==[Qq]
[q] In the diagram below, which structure or cell would be haploid?
[c]IDE=[Qq]
[c]ID Q=[Qq]
[c]IDU=[Qq]
[f]IE5vLg==wqAgTnVtYmVyIDEgaXMgYW4gb3ZhcnkuIE92YXJpYW4gdGlzc3VlLCBsaWtlIGFsbCBzb21hdGljIHRpc3N1ZSwgaXMgZGlwbG9pZC4gSG93ZXZlciwgc29tZSBjZWxscyBpbiBhbiBvdmFyeSBnbyB0aHJvdWdoIG1laW9zaXMgdG8gYmVjb21lIGhhcGxvaWQgZWdncy4gTmV4dCB0aW1lLCBtYWtlIGEgZGlmZmVyZW50IGNob2ljZS4=[Qq]
[f]IENvcnJlY3QuIE51bWJlciA0IGlzIGFuIGVnZy4gRWdncyBhcmUgaGFwbG9pZCBjZWxscyB0aGF0IHJlc3VsdCBmcm9tIG1laW9zaXMu[Qq]
[f]IE5vLiBOdW1iZXIgNSBpcyBhIHp5Z290ZS4gQSB6eWdvdGUgaXMgYSBmZXJ0aWxpemVkIGVnZywgd2l0aCB0d28gc2V0cyBvZiBjaHJvbW9zb21lcywgbWFraW5nIGl0IGRpcGxvaWQuIE5leHQgdGltZSwgbWFrZSBhIGRpZmZlcmVudCBjaG9pY2Uu
Cg==[Qq]
[q] In the diagram below, is the cell at number 5 haploid or diploid?
[c]IGRpcG xvaWQ=[Qq]
[c]IGhhcGxvaWQ=[Qq]
[f]IFllcy4gVGhlIGNlbGwgYXQgbnVtYmVyIDUgaXMgYSB6eWdvdGUuIEEgenlnb3RlIGlzIGEgZmVydGlsaXplZCBlZ2csIHdpdGggdHdvIHNldHMgb2YgY2hyb21vc29tZXMsIG1ha2luZyBpdCBkaXBsb2lkLg==[Qq]
[f]IE5vLiBUaGUgY2VsbCBhdCBudW1iZXIgNSBpcyBhIHp5Z290ZS4gQSB6eWdvdGUgaXMgYSBmZXJ0aWxpemVkIGVnZywgd2l0aCB0d28gc2V0cyBvZiBjaHJvbW9zb21lcywgbWFraW5nIGl0IGRpcGxvaWQu
Cg==[Qq]
[q] In the diagram below, which structure is a zygote?
[c]IDE=[Qq]
[c]IDI=[Qq]
[c]IDM=[Qq]
[c]IDQ=[Qq]
[c]ID U=[Qq]
[f]IE5vLiBOdW1iZXIgMSBpcyB0aGUgb3ZhcnkuIEEgenlnb3RlIGlzIGEgZmVydGlsaXplZCBlZ2csIGFuZCBpdCBjb21lcyBhYm91dCB3aGVuIGEgc3Blcm0gY2VsbCBmZXJ0aWxpemVzIGFuIGVnZy4gV2hlcmUgaW4gdGhlIGRpYWdyYW0gZG8geW91IHNlZSB0aGUgY2VsbCB0aGF0IGZvcm1zIHdoZW4gdHdvIGNlbGxzIGZ1c2UgdG8gYmVjb21lIG9uZT8=[Qq]
[f]IE5vLiBOdW1iZXIgMiBpcyBhIHRlc3RpcyAoc2luZ3VsYXIgZm9yIHRlc3RlcykuIEEgenlnb3RlIGlzIGEgZmVydGlsaXplZCBlZ2csIGFuZCBpdCBjb21lcyBhYm91dCB3aGVuIGEgc3Blcm0gY2VsbCBmZXJ0aWxpemVzIGFuIGVnZy4gV2hlcmUgaW4gdGhlIGRpYWdyYW0gZG8geW91IHNlZSB0aGUgY2VsbCB0aGF0IGZvcm1zIHdoZW4gdHdvIGNlbGxzIGZ1c2UgdG8gYmVjb21lIG9uZT8=[Qq]
[f]IE5vLiBOdW1iZXIgMyBpcyBhIHNwZXJtIGNlbGwuIEEgenlnb3RlIGlzIGEgZmVydGlsaXplZCBlZ2csIGFuZCBpdCBjb21lcyBhYm91dCB3aGVuIGEgc3Blcm0gY2VsbCBmZXJ0aWxpemVzIGFuIGVnZy4gV2hlcmUgaW4gdGhlIGRpYWdyYW0gZG8geW91IHNlZSB0aGUgY2VsbCB0aGF0IGZvcm1zIHdoZW4gdHdvIGNlbGxzIGZ1c2UgdG8gYmVjb21lIG9uZT8=[Qq]
[f]IE5vLiBOdW1iZXIgNCBpcyBhbiBlZ2cgY2VsbC4gQSB6eWdvdGUgaXMgYSBmZXJ0aWxpemVkIGVnZywgYW5kIGl0IGNvbWVzIGFib3V0IHdoZW4gYSBzcGVybSBjZWxsIGZlcnRpbGl6ZXMgYW4gZWdnLiBXaGVyZSBpbiB0aGUgZGlhZ3JhbSBkbyB5b3Ugc2VlIHRoZSBjZWxsIHRoYXQgZm9ybXMgd2hlbiB0d28gY2VsbHMgZnVzZSB0byBiZWNvbWUgb25lPw==[Qq]
[f]IFllcy4gTnVtYmVyIDUgaXMgdGhlIHp5Z290ZSwgd2hpY2ggZm9ybXMgd2hlbiBhIHNwZXJtIGNlbGwgZmVydGlsaXplcyBhbiBlZ2cu
Cg==[Qq]
[q] In the diagram below, would the adult man and woman shown at the bottom of the diagram be diploid or haploid?
[c]IGRpcG xvaWQ=[Qq]
[c]IGhhcGxvaWQ=[Qq]
[f]IFllcy4gQWR1bHRzIG9mIGFueSBhbmltYWwgc3BlY2llcyBoYXZlIGJvZGllcyB0aGF0IGFyZSBjb21wb3NlZCBvZiBkaXBsb2lkIHRpc3N1ZSwgd2l0aCB0d28gc2V0cyBvZiBjaHJvbW9zb21lcy4gVGhpcyB0aXNzdWUgZGV2ZWxvcGVkIGZyb20gYSB6eWdvdGUsIGEgZGlwbG9pZCBjZWxsIHRoYXQgY2FtZSBhYm91dCBmcm9tIHRoZSBmZXJ0aWxpemF0aW9uIG9mIGFuIGVnZyBmcm9tIGEgc3Blcm0u[Qq]
[f]IE5vLiBBZHVsdHMgb2YgYW55IGFuaW1hbCBzcGVjaWVzIGhhdmUgYm9kaWVzIHRoYXQgYXJlIGNvbXBvc2VkIG9mIGRpcGxvaWQgdGlzc3VlLCB3aXRoIHR3byBzZXRzIG9mIGNocm9tb3NvbWVzLiBUaGlzIHRpc3N1ZSBkZXZlbG9wZWQgZnJvbSBhIHp5Z290ZSwgYSBkaXBsb2lkIGNlbGwgdGhhdCBjYW1lIGFib3V0IGZyb20gdGhlIGZlcnRpbGl6YXRpb24gb2YgYW4gZWdnIGZyb20gYSBzcGVybS4gVGhlIG9ubHkgY2VsbHMgaW4gYW4gYWR1bHQgbWFsZSBvciBmZW1hbGUgdGhhdCBhcmUgaGFwbG9pZCBhcmUgdGhlaXIgZ2FtZXRlcyAoc3Blcm0gb3IgZWdnIGNlbGxzLCBkZXBlbmRpbmcgb24gdGhlIHNleCku
Cg==[Qq]
[q] In the diagram below, which structure is an ovary?
[c]ID E=[Qq]
[c]IDI=[Qq]
[c]IDM=[Qq]
[c]IDQ=[Qq]
[c]IDU=[Qq]
[f]IFllcy4gTnVtYmVyIDEgaXMgdGhlIG92YXJ5Lg==[Qq]
[f]IE5vLiBOdW1iZXIgMiBpcyBhIHRlc3RpcyAoc2luZ3VsYXIgZm9yIHRlc3RlcykuIExvb2sgZm9yIHRpc3N1ZSBpbiBhbiBhZHVsdCB0aGF0IHdvdWxkIGdpdmUgcmlzZSB0byBhbiBlZ2csIHdoaWNoIHlvdSBjYW4gc2VlIGluIG51bWJlciA0Lg==[Qq]
[f]IE5vLiBOdW1iZXIgMyBpcyBhIHNwZXJtIGNlbGwuwqAgTG9vayBmb3IgdGlzc3VlIGluIGFuIGFkdWx0IHRoYXQgd291bGQgZ2l2ZSByaXNlIHRvIGFuIGVnZywgd2hpY2ggeW91IGNhbiBzZWUgaW4gbnVtYmVyIDQu[Qq]
[f]IE5vLiBOdW1iZXIgNCBpcyBhbiBlZ2cgY2VsbC4=wqAgTG9vayBmb3IgdGlzc3VlIGluIGFuIGFkdWx0IHRoYXQgd291bGQgZ2l2ZSByaXNlIHRvIHRoaXMgZWdnLg==[Qq]
[f]IE5vLiBOdW1iZXIgNSBpcyB0aGUgenlnb3RlLCB3aGljaCBmb3JtcyB3aGVuIGEgc3Blcm0gY2VsbCBmZXJ0aWxpemVzIGFuIGVnZy4gVG8gaWRlbnRpZnkgdGhlIG92YXJ5LCBsb29rIGZvciB0aXNzdWUgaW4gYW4gYWR1bHQgdGhhdCB3b3VsZCBnaXZlIHJpc2UgdG8gYW4gdW5mZXJ0aWxpemVkIGVnZywgd2hpY2ggeW91IGNhbiBzZWUgYXQgbnVtYmVyIDQu
Cg==[Qq]
[q] In the diagram below, which numbers refer to gametes?
[c]IDEgYW5kIDI=[Qq]
[c]IDMgYW 5kIDQ=[Qq]
[c]IDU=[Qq]
[f]IE5vLiBOdW1iZXJzIDEgYW5kIDIgYXJlIHNob3dpbmcgdGhlIG92YXJ5ICgxKSBhbmQgdGhlIHRlc3RlcyAoYXQgMikuIEdhbWV0ZXMgYXJlIHNleCBjZWxscywgd2hpY2ggYXJlIHByb2R1Y2VkIGJ5IG92YXJpZXMgYW5kIHRlc3Rlcy4gV2hpY2ggbnVtYmVycyByZWZlciB0byBzZXggY2VsbHM/[Qq]
[f]IFllcy4gTnVtYmVyIDMgaXMgYSBzcGVybSBjZWxsLCBhbmQgbnVtYmVyIDQgaXMgYW4gZWdnLiBFZ2cgY2VsbHMgYW5kIHNwZXJtIGNlbGxzIGFyZSBzZXggY2VsbHMgb3IgZ2FtZXRlcy4=[Qq]
[f]IE5vLiBOdW1iZXIgNSBpcyBhIHp5Z290ZSwgd2hpY2ggZm9ybXMgd2hlbiBhIHNwZXJtIGNlbGwgZmVydGlsaXplcyBhbiBlZ2cuIEdhbWV0ZXMgYXJlIHNleCBjZWxscywgd2hpY2ggZnVzZSB0byBmb3JtIGEgenlnb3RlLiBXaGljaCBudW1iZXJzIHJlZmVyIHRvIGNlbGxzIHRoYXQgaGF2ZSBmdXNlZCB0byBmb3JtIGEgenlnb3RlPw==
Cg==[Qq]
[q] In the diagram below, which numbers refer to organs where meiosis would occur?
[c]IDEgYW 5kIDI=[Qq]
[c]IDMgYW5kIDQ=[Qq]
[c]IDU=[Qq]
[f]IFllcy4gTnVtYmVycyAxIGFuZCAyIGFyZSBzaG93aW5nIHRoZSBvdmFyeSAoMSkgYW5kIHRoZSB0ZXN0ZXMgKDIpLiBXaXRoaW4gdGhlc2Ugb3JnYW5zLCBtZWlvc2lzIG9jY3VycywgcHJvZHVjaW5nIHNleCBjZWxscy4=[Qq]
[f]IE5vLiBOdW1iZXIgMyBpcyBhIHNwZXJtIGNlbGwsIGFuZCBudW1iZXIgNCBpcyBhbiBlZ2cuIEVnZyBjZWxscyBhbmQgc3Blcm0gY2VsbHMgYXJlIHNleCBjZWxscyBvciBnYW1ldGVzLiBUaGV5IGFyZSBwcm9kdWNlZCBieSBtZWlvc2lzLCBidXQgbWVpb3NpcyBkb2VzbuKAmXQgb2NjdXIgd2l0aGluIHRoZXNlIGNlbGxzLiBNb3ZlIGJhY2t3YXJkIGluIHRoZSBkaWFncmFtIHRvIGZpbmQgdGhlIHRpc3N1ZXMgdGhhdCBwcm9kdWNlZCB0aGVzZSBnYW1ldGVzLCBhbmQgeW914oCZbGwgaGF2ZSBmb3VuZCB0aGUgbG9jYXRpb24gb2YgbWVpb3Npcy4=[Qq]
[f]IE5vLiBOdW1iZXIgNSBpcyBhIHp5Z290ZSwgd2hpY2ggZm9ybXMgd2hlbiBhIHNwZXJtIGNlbGwgZmVydGlsaXplcyBhbiBlZ2cuIFRvIGZpbmQgd2hlcmUgbWVpb3NpcyBvY2N1cnMsIGZpbmQgdGhlIG9yZ2FucyB0aGF0IHByb2R1Y2VkIHRoZSBzcGVybSBhbmQgZWdnIHRoYXQgZnVzZWQgdG8gZm9ybSB0aGUgenlnb3RlLg==
Cg==[Qq]
[q] Based on the diagram below (and any other knowledge you may have), which of the following statements is true?
[c]IEJlY2F1c2UgdGhlIGVnZyBpcyBzbyBtdWNoIGxhcmdlciB0aGFuIHRoZSBzcGVybSwgbW9yZSBnZW5ldGljIGluZm9ybWF0aW9uIGlzIGNvbnRyaWJ1dGVkIGJ5IHRoZSBtb3RoZXIgdGhhbiBieSB0aGUgZmF0aGVyLg==[Qq]
[c]IFRoZSBzcGVybSBwcm92aWRlcyBtb3N0IG9mIHRoZSBnZW5ldGljIGluZm9ybWF0aW9uLiBUaGUgZWdnIHByb3ZpZGVzIHRoZSBjeXRvcGxhc20gdGhhdCBub3VyaXNoZXMgdGhlIHp5Z290ZS4=[Qq]
[c]IFRoZSBlZ2csIHdpdGggaXRzIGxhcmdlciBudWNsZXVzLCBwcm92aWRlcyBtb3N0IG9mIHRoZSBnZW5ldGljIGluZm9ybWF0aW9uLiBUaGUgc3Blcm0gbWVyZWx5IHNlcnZlcyB0byBhY3RpdmF0ZSB0aGUgenlnb3RlIGFuZCBpbmR1Y2UgaXQgdG8gZGV2ZWxvcCBpbnRvIGFuIGVtYnJ5by4=[Qq]
[c]IEJvdGggcGFyZW50cywgdGhyb3VnaCB0aGVpciBzcGVybSBhbmQgZWdnIGNlbGxzLCBjb250cmlidXRl IDEvMiBvZiB0aGUgZ2VuZXRpYyBpbmZvcm1hdGlvbiByZWNlaXZlZCBieSB0aGUgb2Zmc3ByaW5nLg==[Qq]
[f]IE5vLiBEZXNwaXRlIHRoZWlyIGRpZmZlcmVudCBzaXplcywgYm90aCB0aGUgZWdnIGFuZCBzcGVybSBoYXZlIGVxdWFsIGFtb3VudHMgb2YgZ2VuZXRpYyBpbmZvcm1hdGlvbi4gTmV4dCB0aW1lLCBjaG9zZSBhIGRpZmZlcmVudCBhbnN3ZXIu[Qq]
[f]IE5vLiBXaGlsZSB0aGUgZWdnIGRvZXMgY29udHJpYnV0ZSBtdWNoIG1vcmUgY3l0b3BsYXNtLCBib3RoIHRoZSBlZ2cgYW5kIHNwZXJtIGhhdmUgZXF1YWwgYW1vdW50cyBvZiBnZW5ldGljIGluZm9ybWF0aW9uLiBOZXh0IHRpbWUsIGNob3NlIGEgZGlmZmVyZW50IGFuc3dlci4=[Qq]
[f]IE5vLiBFdmVuIHRob3VnaCB0aGlzIGRpYWdyYW0gc2hvd3MgYSBtdWNoIGxhcmdlciBudWNsZXVzIGluIHRoZSBlZ2csIHRoZSBlZ2csIGhhcyBubyBtb3JlIGdlbmV0aWMgaW5mb3JtYXRpb24gdGhhbiB0aGUgc3Blcm0uIE5leHQgdGltZSwgY2hvc2UgYSBkaWZmZXJlbnQgYW5zd2VyLg==[Qq]
[f]IENvcnJlY3QuIEhhbGYgb2YgdGhlIGdlbmV0aWMgaW5mb3JtYXRpb24gaXMgY29udHJpYnV0ZWQgYnkgdGhlIG1vdGhlciwgYW5kIGhhbGYgaXMgY29udHJpYnV0ZWQgYnkgdGhlIGZhdGhlci4=
Cg==[Qq]
[q] Based on the diagram below (and any other knowledge you may have), which of the following statements about fertilization is true?
[c]IER1cmluZyBmZXJ0aWxpemF0aW9uLCB0d28gZGlwbG9pZCB6eWdvdGVzIGZ1c2UgdG8gZm9ybSBoYXBsb2lkIGdhbWV0ZXMu[Qq]
[c]IER1cmluZyBmZXJ0aWxpemF0aW9uLCB0d28gZGlwbG9pZCBnYW1ldGVzIGZ1c2UgdG8gZm9ybSBhIGhhcGxvaWQgenlnb3RlLg==[Qq]
[c]IEZlcnRpbGl6YXRpb24gY3JlYXRlcyBhIGRpcGxvaWQgenlnb3RlIG Zyb20gdGhlIGZ1c2lvbiBvZiB0d28gaGFwbG9pZCBnYW1ldGVzLg==[Qq]
[f]IE5vLiBMb29rIGF0IHRoZSBkaXJlY3Rpb24gb2YgdGhlIGFycm93cyBpbiB0aGUgZGlhZ3JhbS4gVGhlIHNwZXJtIGFuZCBlZ2cgY2VsbCBtb3ZlIGZvcndhcmQgaW4gdGltZSB0byBiZWNvbWUgYSB6eWdvdGUuIEluIGFkZGl0aW9uLCByZW1lbWJlciB0aGF0IGVhY2ggZ2FtZXRlIGhhcyBvbmx5IG9uZSBjaHJvbW9zb21lIHNldCAobWFraW5nIGl0IGhhcGxvaWQpLCB3aGlsZSB0aGUgenlnb3RlIGhhcyB0d28u[Qq]
[f]IE5vLiBXaGlsZSB5b3UgaGF2ZSB0aGUgb3ZlcmFsbCBzZXF1ZW5jZSBjb3JyZWN0IChnYW1ldGVzIGZ1c2UgdG8gZm9ybSBhIHp5Z290ZSksIHlvdSBuZWVkIHRvIGNsYXJpZnkgdGhlIGNocm9tb3NvbWFsIGNvbmRpdGlvbiBvZiB0aGUgZ2FtZXRlcyBhbmQgdGhlIHp5Z290ZS4gUmVtZW1iZXJpbmcgdGhhdCB0aGUg4oCYZGnigJkgaW4g4oCYZGlwbG9pZOKAmSBtZWFucyDigJh0d2/igJkgbWlnaHQgaGVscCB5b3UgdGhlIG5leHQgdGltZSB5b3Ugc2VlIHRoaXMgcXVlc3Rpb24u[Qq]
[f]IFllcy4gVGhhdOKAmXMgZXhhY3RseSB3aGF0IGhhcHBlbnMgaW4gZmVydGlsaXphdGlvbiB3aGVuIHR3byBoYXBsb2lkIGdhbWV0ZXMgZnVzZSB0byBmb3JtIGEgZGlwbG9pZCB6eWdvdGUu[Qq]
[x]
[restart]
[/qwiz]
4. Meiosis Involves Two Cell Divisions
As described above, meiosis takes diploid germ cells in the ovaries or testes and transforms them into haploid gametes. But there’s a fact about meiosis that can be confusing. Meiosis evolved from (or with) mitosis. As a result, meiosis (like mitosis) begins with interphase. During interphase, chromosomes are replicated, becoming two connected sister chromatids.
Because of this, meiosis involves two cell divisions. After replication (“1” below), there’s meiosis 1 (which is shown as “2” in the diagram below), followed by meiosis 2 (“3” below)
Focusing solely on homologous pairs and sister chromatids, here’s what happens during each division:
- Meiosis 1 (“2” below): homologous pairs are separated. Diploid cells become haploid.
- Meiosis 2 (“3” below): sister chromatids are pulled apart, creating four haploid gametes.
Got it? Take this quiz to help consolidate your understanding of the difference between meiosis 1 and meiosis 2.
5. Quiz: Meiosis 1 v. Meiosis 2
[qwiz qrecord_id=”sciencemusicvideosMeister1961-Meiosis 1 v. Meiosis 2 (v2.0)”]
[h]Quiz: Meiosis 1 v. Meiosis 2
[i]
[q] In the diagram below, which number shows the separation of homologous pairs?
[c]IDE=[Qq]
[c]ID I=[Qq]
[c]IDM=[Qq]
[f]IE5vLiBOb3RpY2UgaG93IHRoZSBob21vbG9nb3VzIHBhaXJzICh0aGUgY2hyb21vc29tZXMgdGhhdCBhcmUgc2hvd24gYXMgYmVpbmcgbWF0Y2hlZCBieSBzaXplIGJ1dCBub3QgY29sb3IpLCBhcmUgc3RpbGwgdG9nZXRoZXIgaW5zaWRlIHRoZSBzYW1lIG51Y2xldXMgYWZ0ZXIgc3RlcCBvbmUuIEZpbmQgYSBzdGVwIHdoZXJlIHRoZXNlIGhvbW9sb2dvdXMgY2hyb21vc29tZXMgaGF2ZSBiZWVuIHNlcGFyYXRlZCBpbnRvIGRpZmZlcmVudCBudWNsZWku[Qq]
[f]IEV4YWN0bHkuIFN0ZXAgMiBzaG93cyBob21vbG9nb3VzIHBhaXJzIGJlaW5nIHNlcGFyYXRlZCBpbnRvIGRpZmZlcmVudCBkYXVnaHRlciBjZWxscy4=[Qq]
[f]IE5vLiBJbiBzdGVwIHRocmVlLCB0aGUgaG9tb2xvZ291cyBwYWlycyBoYXZlIGFscmVhZHkgYmVlbiBzZXBhcmF0ZWQuIFRocmVlIHNob3dzIHNpc3RlciBjaHJvbWF0aWRzIGJlaW5nIHB1bGxlZCBhcGFydC4gTmV4dCB0aW1lLCBjaG9vc2UgYW4gZWFybGllciBzdGVwIGluIHRoZSBwcm9jZXNzLg==
Cg==[Qq]
[q] In the diagram below, which number shows the separation of sister chromatids?
[c]IDE=[Qq]
[c]IDI=[Qq]
[c]ID M=[Qq]
[f]IE5vLiBJbiB0aGlzIGZpcnN0IHN0ZXAsIHlvdSBjYW4gc2VlIHNpbmdsZSBjaHJvbW9zb21lcyBiZWNvbWluZyBkb3VibGVkIGNocm9tb3NvbWVzLCB3aGljaCBhcmUgY29tcG9zZWQgb2Ygc2lzdGVyIGNocm9tYXRpZHMuIE5leHQgdGltZSwgdHJ5IHRvIGlkZW50aWZ5IGEgc3RlcCB3aGVyZSB0aGVzZSBzaXN0ZXIgY2hyb21hdGlkcyBhcmUgcHVsbGVkIGFwYXJ0Lg==[Qq]
[f]IE5vLiBTdGVwIDIgc2hvd3MgaG9tb2xvZ291cyBwYWlycyBiZWluZyBzZXBhcmF0ZWQgaW50byBkaWZmZXJlbnQgZGF1Z2h0ZXIgY2VsbHMu[Qq]
[f]IENvcnJlY3QuIEluIHN0ZXAgdGhyZWUsIHNpc3RlciBjaHJvbWF0aWRzIGFyZSBwdWxsZWQgYXBhcnQu
Cg==[Qq]
[q] In the diagram below, which number shows the duplication of chromosomes?
[c]ID E=[Qq]
[c]IDI=[Qq]
[c]IDM=[Qq]
[f]IFllcy4gSW4gdGhpcyBmaXJzdCBzdGVwLCB5b3UgY2FuIHNlZSBzaW5nbGUgY2hyb21vc29tZXMgYmVjb21pbmcgZG91YmxlZCBjaHJvbW9zb21lcywgZWFjaCBvZiB3aGljaCBpcyBjb21wb3NlZCBvZiBzaXN0ZXIgY2hyb21hdGlkcy4=[Qq]
[f]IE5vLiBTdGVwIDIgc2hvd3MgaG9tb2xvZ291cyBwYWlycyBiZWluZyBzZXBhcmF0ZWQgaW50byBkaWZmZXJlbnQgZGF1Z2h0ZXIgY2VsbHMuIEZpbmQgYSBzdGVwIHdoZXJlIHNpbmdsZSBjaHJvbW9zb21lcywgd2hpY2ggbG9vayBsaWtlIHRoaWNrIGxpbmVzLCBiZWNvbWUgZG91YmxlZCBjaHJvbW9zb21lcyAod2hpY2ggbG9vayBzb21ld2hhdCBsaWtlIGFuIOKAmFjigJkpLg==[Qq]
[f]IE5vLiBJbiBzdGVwIHRocmVlLCBzaXN0ZXIgY2hyb21hdGlkcyBhcmUgcHVsbGVkIGFwYXJ0LiBXaGF0IHlvdeKAmXJlIGxvb2tpbmcgZm9yIGlzIHRoZSBvcHBvc2l0ZS4gRmluZCBhIHN0ZXAgd2hlcmUgc2luZ2xlIGNocm9tb3NvbWVzLCB3aGljaCBsb29rIGxpa2UgdGhpY2sgbGluZXMsIGJlY29tZSBkb3VibGVkIGNocm9tb3NvbWVzICh3aGljaCBsb29rIHNvbWV3aGF0IGxpa2UgYW4g4oCYWOKAmSku
Cg==[Qq]
[q] In the diagram below, which number shows where the cell changes from diploid to haploid?
[c]IDE=[Qq]
[c]ID I=[Qq]
[c]IDM=[Qq]
[f]IE5vLiBJbiB0aGlzIGZpcnN0IHN0ZXAsIHlvdSBjYW4gc2VlIHNpbmdsZSBjaHJvbW9zb21lcyBiZWNvbWluZyBkb3VibGVkIGNocm9tb3NvbWVzLCBlYWNoIG9mIHdoaWNoIGlzIGNvbXBvc2VkIG9mIHNpc3RlciBjaHJvbWF0aWRzLiBZb3XigJlyZSBsb29raW5nIGZvciB0aGUgc3RhZ2Ugd2hlcmUgdGhlIG1hdGNoZWQgaG9tb2xvZ291cyBwYWlycyBnZXQgc2VudCB0byBkaWZmZXJlbnQgZGF1Z2h0ZXIgY2VsbHMu[Qq]
[f]IFBlcmZlY3QuIFN0ZXAgMiBzaG93cyBob21vbG9nb3VzIHBhaXJzIGJlaW5nIHNlcGFyYXRlZCBpbnRvIGRpZmZlcmVudCBkYXVnaHRlciBjZWxscy4gQXMgdGhhdCBoYXBwZW5zLCB0aGUgY2VsbCBpcyB0cmFuc2Zvcm1lZCBmcm9tIGhhdmluZyB0d28gY2hyb21vc29tZSBzZXRzIHRvIGhhdmluZyBvbmUuIEFub3RoZXIgd2F5IG9mIHNheWluZyB0aGlzIGlzIHRoYXQgdGhlIGNlbGwgaXMgY2hhbmdpbmcgZnJvbSBkaXBsb2lkIHRvIGhhcGxvaWQu[Qq]
[f]IE5vLiBJbiBzdGVwIHRocmVlLCBzaXN0ZXIgY2hyb21hdGlkcyBhcmUgcHVsbGVkIGFwYXJ0LiBCeSB0aGlzIHBvaW50LCB0aGUgY2VsbHMgYXJlIGFscmVhZHkgaGFwbG9pZCAoYnV0IHRoZWlyIGNocm9tb3NvbWVzIGFyZSBzdGlsbCBkb3VibGVkKS4gTmV4dCB0aW1lLCBjaG9vc2UgYW4gZWFybGllciBwaGFzZSBpbiB0aGUgcHJvY2Vzcy4=
Cg==[Qq]
[q] In the diagram below, which number shows a process that results in haploid gametes with single chromosomes?
[c]IDE=[Qq]
[c]IDI=[Qq]
[c]ID M=[Qq]
[f]IE5vLiBJbiB0aGlzIGZpcnN0IHN0ZXAsIHlvdSBjYW4gc2VlIHNpbmdsZSBjaHJvbW9zb21lcyBiZWNvbWluZyBkb3VibGVkIGNocm9tb3NvbWVzLCBlYWNoIG9mIHdoaWNoIGlzIGNvbXBvc2VkIG9mIHR3byBzaXN0ZXIgY2hyb21hdGlkcy4gWW914oCZcmUgbG9va2luZyBmb3IgYSBsYXRlciBzdGFnZSBpbiB0aGUgcHJvY2Vzcy4=[Qq]
[f]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[Qq]
[f]IE5pY2UuIEluIHN0ZXAgdGhyZWUsIHNpc3RlciBjaHJvbWF0aWRzIGFyZSBiZWluZyBwdWxsZWQgYXBhcnQsIHNvIHRoZSBkb3VibGVkIGNocm9tb3NvbWVzIGFyZSBiZWNvbWluZyBzaW5nbGUgY2hyb21vc29tZXMuIEJ5IHRoaXMgcG9pbnQsIHRoZSBjZWxscyBhcmUgYWxyZWFkeSBoYXBsb2lkLiBUaGUgcmVzdWx0LCBpbiBvdGhlciB3b3JkcywgaXMgZm91ciBoYXBsb2lkIGdhbWV0ZXMgd2l0aCBzaW5nbGUgY2hyb21vc29tZXMu
Cg==[Qq]
[q] Which process separates homologous pairs?
[c]IG1laW9z aXMgMQ==[Qq]
[c]IG1laW9zaXMgMg==[Qq]
[f]IFRoYXTigJlzIHJpZ2h0LiBNZWlvc2lzIDEgc2VwYXJhdGVzIGhvbW9sb2dvdXMgcGFpcnMu[Qq]
[f]IE5vLiBNZWlvc2lzIDIgc2VwYXJhdGVzIHNpc3RlciBjaHJvbWF0aWRzLg==
Cg==[Qq]
[q] Which process reduces chromosome number from diploid to haploid?
[c]IG1laW9z aXMgMQ==[Qq]
[c]IG1laW9zaXMgMg==[Qq]
[f]IFRoYXTigJlzIHJpZ2h0LiBNZWlvc2lzIDEgc2VwYXJhdGVzIGhvbW9sb2dvdXMgcGFpcnMuIEFzIGl0IGRvZXMsIHRoZSBjaHJvbW9zb21lIG51bWJlciBpcyByZWR1Y2VkIGZyb20gdHdvIHNldHMgKG9uZSBmcm9tIHRoZSBtb3RoZXIsIG9uZSBmcm9tIHRoZSBmYXRoZXIpLCB0byBvbmUgc2V0Lg==[Qq]
[f]IE5vLiBNZWlvc2lzIDIgc2VwYXJhdGVzIHNpc3RlciBjaHJvbWF0aWRzLiBUaGUgY2VsbHMgYXJlIGFscmVhZHkgaGFwbG9pZC4=
Cg==[Qq]
[q] Which process results in two haploid cells with doubled chromosomes?
[c]IG1laW9z aXMgMQ==[Qq]
[c]IG1laW9zaXMgMg==[Qq]
[f]IFRoYXTigJlzIHJpZ2h0LiBNZWlvc2lzIDEgc2VwYXJhdGVzIGhvbW9sb2dvdXMgcGFpcnMuIEFzIGl0IGRvZXMsIGNocm9tb3NvbWUgbnVtYmVyIGdvZXMgZnJvbSBkaXBsb2lkIHRvIGhhcGxvaWQuIEVhY2ggY2hyb21vc29tZSwgaG93ZXZlciwgaXMgc3RpbGwgZG91YmxlZC4=[Qq]
[f]IE5vLiBNZWlvc2lzIDIgc2VwYXJhdGVzIHNpc3RlciBjaHJvbWF0aWRzLiBUaGUgcmVzdWx0IGlzIGZvdXIgaGFwbG9pZCBkYXVnaHRlciBjZWxscywgZWFjaCBvZiB3aGljaCBoYXMgc2luZ2xlIGNocm9tb3NvbWVzLg==
Cg==[Qq]
[q] Which process separates sister chromatids?
[c]IG1laW9zaXMgMQ==[Qq]
[c]IG1laW9z aXMgMg==[Qq]
[f]IE5vLiBNZWlvc2lzIDEgc2VwYXJhdGVzIGhvbW9sb2dvdXMgcGFpcnMu[Qq]
[f]IEdvb2Qgam9iLiBNZWlvc2lzIDIgc2VwYXJhdGVzIHNpc3RlciBjaHJvbWF0aWRzLg==
Cg==[Qq]
[q] Which process results in four haploid cells with single chromosomes?
[c]IG1laW9zaXMgMQ==[Qq]
[c]IG1laW9z aXMgMg==[Qq]
[f]IE5vLiBNZWlvc2lzIDEgc2VwYXJhdGVzIGhvbW9sb2dvdXMgcGFpcnMuIFRoZSByZXN1bHQgaXMgdHdvIGhhcGxvaWQgY2VsbHMgd2l0aCBkb3VibGVkIGNocm9tb3NvbWVzLg==[Qq]
[f]IFRoYXTigJlzIGNvcnJlY3QuIE1laW9zaXMgMiBzZXBhcmF0ZXMgc2lzdGVyIGNocm9tYXRpZHMuIFRoZSByZXN1bHQgaXMgZm91ciBoYXBsb2lkIGRhdWdodGVyIGNlbGxzLCBlYWNoIG9mIHdoaWNoIGhhcyBzaW5nbGUgY2hyb21vc29tZXMu
Cg==[Qq]
[q] Which process reduces chromosomes from two sets to one set?
[c]IG1laW9z aXMgMQ==[Qq]
[c]IG1laW9zaXMgMg==[Qq]
[f]IEV4YWN0bHkuIE1laW9zaXMgMSBzZXBhcmF0ZXMgaG9tb2xvZ291cyBwYWlycy4gVGhlIHJlc3VsdCBpcyB0d28gZGF1Z2h0ZXIgY2VsbHMsIGVhY2ggd2l0aCBvbmUgc2V0IG9mIGNocm9tb3NvbWVzLiBJbiBlYWNoIHNldCwgdGhlIGNocm9tb3NvbWVzIGFyZSBzdGlsbCBkb3VibGVkLg==[Qq]
[f]IE5vLiBNZWlvc2lzIDIgc2VwYXJhdGVzIHNpc3RlciBjaHJvbWF0aWRzLiBNZWlvc2lzIDEgaGFzIGFscmVhZHkgY3V0IHRoZSBudW1iZXIgb2YgY2hyb21vc29tZXMgZG93biB0byBvbmUgc2V0Lg==
Cg==[Qq]
[q] Which process changes doubled chromosomes into single chromosomes?
[c]IG1laW9zaXMgMQ==[Qq]
[c]IG1laW9z aXMgMg==[Qq]
[f]IE5vLiBNZWlvc2lzIDEgc2VwYXJhdGVzIGhvbW9sb2dvdXMgcGFpcnMuIEVhY2ggcmVzdWx0aW5nIGNocm9tb3NvbWUgaXMgc3RpbGwgZG91YmxlZC4=[Qq]
[f]IFllcy4gTWVpb3NpcyAyIHNlcGFyYXRlcyBzaXN0ZXIgY2hyb21hdGlkcy4gVGhpcyBjaGFuZ2VzIGRvdWJsZWQgY2hyb21vc29tZXMgKGNvbnNpc3Rpbmcgb2YgdHdvIHNpc3RlciBjaHJvbWF0aWRzKQ==wqAgaW50byBzaW5nbGUgY2hyb21vc29tZXMu[Qq]
[x]
[restart]
[/qwiz]
6. Comparing Mitosis and Meiosis
At this point, it makes sense to review the differences between mitosis and meiosis. To do so, try the quiz below.
[qwiz qrecord_id=”sciencemusicvideosMeister1961-Mitosis v. Meiosis (v2.0)”]
[h]Meiosis Quiz 2: Meiosis v. Mitosis
[i]
[q] The kind of cell division associated with sexual reproduction:
[c]IG1laW 9zaXM=[Qq]
[c]IG1pdG9zaXM=[Qq]
[f]IENvcnJlY3QuIFNleHVhbCByZXByb2R1Y3Rpb24gcmVxdWlyZXMgdGhlIHByb2R1Y3Rpb24gb2YgaGFwbG9pZCBnYW1ldGVzLCBhbmQgdGhlc2UgYXJlIHByb2R1Y2VkIHRocm91Z2ggbWVpb3Npcy4=[Qq]
[f]IE5vLiBNaXRvc2lzIGlzIGFzc29jaWF0ZWQgd2l0aCBhc2V4dWFsIHJlcHJvZHVjdGlvbiAoaW4gdW5pY2VsbHVsYXIgZXVrYXJ5b3RlcykuIEluIG11bHRpY2VsbHVsYXIgb3JnYW5pc21zIGxpa2UgaHVtYW5zLCBtaXRvc2lzIGlzIGhvdyB3ZSBncm93IGFuZCBkZXZlbG9wLg==[Qq]
[q] Somatic cells reproduce themselves through
[c]IG1laW9zaXM=[Qq]
[c]IG1pdG 9zaXM=[Qq]
[f]IE5vLiBNZWlvc2lzIGlzIGhvdyBzZXggY2VsbHMgKGVnZyBhbmQgc3Blcm0gY2VsbHMpIGFyZSBwcm9kdWNlZC4=[Qq]
[f]IFllcy4gTWl0b3NpcyBpcyBob3cgdGhlIHNvbWF0aWMgY2VsbHMgdGhhdCBtYWtlIHVwIG91ciBib2R5IHRpc3N1ZXMgcmVwcm9kdWNlIHRoZW1zZWx2ZXMuIFlvdSBncmV3IGZyb20gYSBzaW5nbGUtY2VsbGVkIHp5Z290ZSBpbnRvIHRoZSB0cmlsbGlvbnMgb2YgY2VsbHMgdGhhdCBtYWtlIHlvdSB1cCB0b2RheSB0aHJvdWdoIG1pdG9zaXMu[Qq]
[q] Gametes are created through
[c]IG1laW 9zaXM=[Qq]
[c]IG1pdG9zaXM=[Qq]
[f]IFllcy4gTWVpb3NpcyBpcyBob3cgZ2FtZXRlcyAoZWdnIGFuZCBzcGVybSBjZWxscykgYXJlIHByb2R1Y2VkLg==[Qq]
[f]IE5vLiBNaXRvc2lzIGlzIGhvdyB0aGUgc29tYXRpYyBjZWxscyB0aGF0IG1ha2UgdXAgb3VyIGJvZHkgdGlzc3VlcyBhcmUgcHJvZHVjZWQu[Qq]
[q] Genetic variation arises through
[c]IG1laW 9zaXM=[Qq]
[c]IG1pdG9zaXM=[Qq]
[f]IFllcy4gTWVpb3NpcyBjcmVhdGVzIHZhcmlhdGlvbi4gTWVpb3NpcyBpbnZvbHZlcyB0d28gcHJvY2Vzc2VzLCBjcm9zc2luZyBvdmVyIGFuZCBpbmRlcGVuZGVudCBhc3NvcnRtZW50LCB0aGF0IG1peCB1cCBnZW5lcyBpbiBhIHdheSB0aGF0IGNyZWF0ZXMgYnJhbmQgbmV3IGNvbWJpbmF0aW9ucyBvZiBnZW5lcy4=[Qq]
[f]IE5vLiBNaXRvc2lzIGNyZWF0ZXMgYW4gZXhhY3QgZHVwbGljYXRlIG9mIHRoZSBwYXJlbnQgY2VsbC4gVGhlIGRhdWdodGVyIGNlbGxzIHdoaWNoIHJlc3VsdCBmcm9tIG1pdG9zaXMgYXJlIGdlbmV0aWMgY2xvbmVzIG9mIHRoZSBwYXJlbnQgY2VsbC4gTm8gbmV3IGdlbmV0aWMgdmFyaWF0aW9uIGlzIHByb2R1Y2VkLg==[Qq]
[q] Which type of cell division cuts chromosome number in half?
[c]IG1laW 9zaXM=[Qq]
[c]IG1pdG9zaXM=[Qq]
[f]IFllcy4gTWVpb3NpcyByZWR1Y2VzIGNocm9tb3NvbWUgbnVtYmVyIGZyb20gdHdvIHNldHMgdG8gb25lIHNldCAoZnJvbSBkaXBsb2lkIHRvIGhhcGxvaWQpLg==[Qq]
[f]IE5vLiBNaXRvc2lzIGtlZXBzIHRoZSBjaHJvbW9zb21lIG51bWJlciB0aGUgc2FtZS4=[Qq]
[q] Which type of cell division creates two daughter cells that are genetic clones of the parent cell?
[c]IG1laW9zaXM=[Qq]
[c]IG1pdG 9zaXM=[Qq]
[f]IE5vLiBNZWlvc2lzIGNyZWF0ZXMgZm91ciBkYXVnaHRlciBjZWxscyB0aGF0IGFyZSBnZW5ldGljYWxseSBkaXN0aW5jdCBmcm9tIHRoZSBwYXJlbnQgY2VsbC4=[Qq]
[f]IFllcy4gTWl0b3NpcyByZXN1bHRzIGluIHR3byBkYXVnaHRlciBjZWxscyB0aGF0IGFyZSBleGFjdCBnZW5ldGljIGNsb25lcyBvZiB0aGUgcGFyZW50IGNlbGwu[Qq]
[q] Animals grow from single-celled zygotes into multicellular organisms through
[c]IG1laW9zaXM=[Qq]
[c]IG1pdG 9zaXM=[Qq]
[f]IE5vLiBNZWlvc2lzIGlzIGhvdyBtdWx0aWNlbGx1bGFyIG9yZ2FuaXNtcyBtYWtlIGdhbWV0ZXMgZm9yIHJlcHJvZHVjdGlvbi4=[Qq]
[f]IFllcy4gTWl0b3NpcyBpcyBob3cgYW5pbWFscyBncm93IGZyb20gYSBzaW5nbGUtY2VsbGVkIHp5Z290ZSBpbnRvIG11bHRpY2VsbHVsYXIgYWR1bHRzLg==[Qq]
[q] Animals create sperm and egg cells created through
[c]IG1laW 9zaXM=[Qq]
[c]IG1pdG9zaXM=[Qq]
[f]IFllcy4gTWVpb3NpcyBpcyBob3cgZ2FtZXRlcyAoZWdnIGFuZCBzcGVybSBjZWxscykgYXJlIHByb2R1Y2VkLg==[Qq]
[f]IE5vLiBNaXRvc2lzIGlzIGhvdyB0aGUgc29tYXRpYyBjZWxscyB0aGF0IG1ha2UgdXAgb3VyIGJvZHkgdGlzc3VlcyBhcmUgY3JlYXRlZC4=[Qq]
[q] Which type of cell division involves only one round of cell division?
[c]IG1laW9zaXM=[Qq]
[c]IG1pdG 9zaXM=[Qq]
[f]IE5vLiBEdXJpbmcgbWVpb3NpcywgY2VsbHMgZGl2aWRlIHR3aWNlIGFzIHRoZXkgcmVkdWNlIGNocm9tb3NvbWUgbnVtYmVyIGZyb20gZGlwbG9pZCB0byBoYXBsb2lkLCBhbmQgdGhlbiBkaXZpZGUgZG91YmxlZCBjaHJvbW9zb21lcyBpbnRvIHNpbmdsZSBjaHJvbW9zb21lcy4=[Qq]
[f]IFllcy4gTWl0b3NpcyBpbnZvbHZlcyBvbmx5IG9uZSByb3VuZCBvZiBjZWxsIGRpdmlzaW9uIGFzIGRvdWJsZWQgY2hyb21vc29tZXMgYXJlIHNwbGl0IGludG8gc2luZ2xlIGNocm9tb3NvbWVzLCBhbmQgdGhlIGNlbGwgc3BsaXRzIGluIGhhbGYu[Qq]
[q] Which type of cell division involves two rounds of cell division?
[c]IG1laW 9zaXM=[Qq]
[c]IG1pdG9zaXM=[Qq]
[f]IFllcy4gRHVyaW5nIG1laW9zaXMsIGNlbGxzIGRpdmlkZSB0d2ljZSBhcyB0aGV5IHJlZHVjZSBjaHJvbW9zb21lIG51bWJlciBmcm9tIGRpcGxvaWQgdG8gaGFwbG9pZCwgYW5kIHRoZW4gZGl2aWRlIGRvdWJsZWQgY2hyb21vc29tZXMgaW50byBzaW5nbGUgY2hyb21vc29tZXMu[Qq]
[f]IE5vLiBNaXRvc2lzIGludm9sdmVzIG9ubHkgb25lIHJvdW5kIG9mIGNlbGwgZGl2aXNpb24gYXMgZG91YmxlZCBjaHJvbW9zb21lcyBhcmUgc3BsaXQgaW50byBzaW5nbGUgY2hyb21vc29tZXMsIGFuZCB0aGUgY2VsbCBzcGxpdHMgaW4gaGFsZi4=[Qq]
[q] Which of the numbered diagrams below represents meiosis?
[c]IDE=[Qq]
[c]ID I=[Qq]
[f]IE5vLiBJbiBkaWFncmFtIDEsIHlvdSBzZWUgb25seSBvbmUgcm91bmQgb2YgY2VsbCBkaXZpc2lvbi4gRHVyaW5nIG1laW9zaXMsIGNlbGxzIGRpdmlkZSB0d2ljZSBhcyB0aGV5IHJlZHVjZSBjaHJvbW9zb21lIG51bWJlciBmcm9tIGRpcGxvaWQgdG8gaGFwbG9pZCwgYW5kIHRoZW4gZGl2aWRlIGRvdWJsZWQgY2hyb21vc29tZXMgaW50byBzaW5nbGUgY2hyb21vc29tZXMu[Qq]
[f]IEV4Y2VsbGVudC4gRGlhZ3JhbSAyIHJlcHJlc2VudHMgbWVpb3Npcywgd2hpY2ggeW91IGNhbiBzZWUgaXMgaGFwcGVuaW5nIGJlY2F1c2Ugb2YgdGhlIHR3byByb3VuZHMgb2YgY2VsbCBkaXZpc2lvbiB0aGF0IGFyZSBvY2N1cnJpbmcsIGFuZCBiZWNhdXNlIHRoZSBjaHJvbW9zb21lIG51bWJlciBpcyBiZWluZyByZWR1Y2VkIGluIGhhbGYgKGZvdXIgaW4gdGhlIHBhcmVudCBjZWxsLCB0d28gaW4gdGhlIGRhdWdodGVyIGNlbGxzKS4=[Qq]
[q] Which of the numbered diagrams below represents mitosis?
[c]ID E=[Qq]
[c]IDI=[Qq]
[f]IFllcy4gSW4gZGlhZ3JhbSAxLCB5b3Ugc2VlIG9ubHkgb25lIHJvdW5kIG9mIGNlbGwgZGl2aXNpb24uIEluIGFkZGl0aW9uLCB5b3UgY2FuIHNlZSB0aGF0IHRoZSBjaHJvbW9zb21lIG51bWJlciBzdGF5cyB0aGUgc2FtZSBpbiBib3RoIHBhcmVudCBjZWxscyBhbmQgZGF1Z2h0ZXIgY2VsbHMuIEJvdGggb2YgdGhlc2UgaW5kaWNhdGUgdGhhdCB3aGF0IHlvdeKAmXJlIHNlZWluZyBpcyBtaXRvc2lzLg==[Qq]
[f]IE5vLiBEaWFncmFtIDIgcmVwcmVzZW50cyBtZWlvc2lzLCB3aGljaCB5b3UgY2FuIHNlZSBpcyBoYXBwZW5pbmcgYmVjYXVzZSBvZiB0aGUgdHdvIHJvdW5kcyBvZiBjZWxsIGRpdmlzaW9uIHRoYXQgYXJlIG9jY3VycmluZywgYW5kIGJlY2F1c2UgdGhlIGNocm9tb3NvbWUgbnVtYmVyIGlzIGJlaW5nIHJlZHVjZWQgaW4gaGFsZiAoZm91ciBpbiB0aGUgcGFyZW50IGNlbGwsIHR3byBpbiB0aGUgZGF1Z2h0ZXIgY2VsbHMpLiBJbiBtaXRvc2lzLCB5b3Ugc2VlIG9ubHkgb25lIHJvdW5kIG9mIGNlbGwgZGl2aXNpb24sIGFuZCB0aGUgY2hyb21vc29tZSBudW1iZXIgc3RheXMgdGhlIHNhbWUu[Qq]
[q] Which of the following statements about mitosis and meiosis is true?
[c]IE1pdG9zaXMgYW5kIG1laW9zaXMgYXJlIHVuaXZlcnNhbCBwcm9jZXNzZXMgdGhhdCBvY2N1ciBpbiBib3RoIHByb2thcnlvdGVzIGFuZCBldWthcnlvdGVzLg==[Qq]
[c]IE1pdG9zaXMgb2NjdXJzIGluIHByb2thcnlvdGVzLiBNZWlvc2lzIG9jY3VycyBpbiBldWthcnlvdGVzLg==[Qq]
[c]IE1pdG9zaXMgYW5kIG1laW9zaXMgb2NjdXIgaW4gcHJva2FyeW90ZXMgb25seS4=[Qq]
[c]IE1pdG9zaXMgYW5kIG1laW9zaXMgb2Nj dXIgaW4gZXVrYXJ5b3RlcyBvbmx5Lg==[Qq]
[f]IE5vLiBNaXRvc2lzIGFuZCBtZWlvc2lzIG5ldmVyIG9jY3VyIGluIHByb2thcnlvdGVzLiBOZXh0IHRpbWUsIGNob29zZSBhbm90aGVyIGFuc3dlci4=[Qq]
[f]IE5vLiBNaXRvc2lzIGFuZCBtZWlvc2lzIG5ldmVyIG9jY3VyIGluIHByb2thcnlvdGVzLiBOZXh0IHRpbWUsIGNob29zZSBhbm90aGVyIGFuc3dlci4=[Qq]
[f]IE5vLiBNaXRvc2lzIGFuZCBtZWlvc2lzIG5ldmVyIG9jY3VyIGluIHByb2thcnlvdGVzLiBOZXh0IHRpbWUsIGNob29zZSBhbm90aGVyIGFuc3dlci4=[Qq]
[f]IEV4YWN0bHkuIEJvdGggbWl0b3NpcyBhbmQgbWVpb3NpcyBhcmUgY2VsbCBkaXZpc2lvbiBwcm9jZXNzZXMgdGhhdCBhcmUgdW5pcXVlIHRvIGV1a2FyeW90ZXMu[Qq]
[x]
[restart]
[/qwiz]
What Now?
Now that we’ve got the basics of meiosis covered, we can go on to Topics 5.1 – 5.2, Part 3: How Meiosis Creates Variation