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Today is Thursday, November 7 th , 2013

In This Lesson: Unit 4 Chromosomes and Gametes (Lesson 1 of 3). Today is Thursday, November 7 th , 2013. Pre-Class: (it’s a simple one) Where do cells come from?. Because they don’t come from this ---------->. http://animalsneedkisses.files.wordpress.com/2009/03/teenage _.... jpg.

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Today is Thursday, November 7 th , 2013

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  1. In This Lesson: Unit 4 Chromosomes and Gametes (Lesson 1 of 3) Today is Thursday,November 7th, 2013 Pre-Class: (it’s a simple one) Where do cells come from? Because they don’t come from this ----------> http://animalsneedkisses.files.wordpress.com/2009/03/teenage_....jpg

  2. Today’s Agenda • Chromosomes • Chromosomes • And maybe strawberries… • Where is this in my book? • Academic: P. 244 and following and P. 341 and following… • Honors: P. 126 and following… http://www.toppstraders.org/blog/wp-content/uploads/2008/02/...ry.jpg

  3. What a cell wants, what a cell needs… • So what exactly does a cell need? • Imagine a cell has just been “born.” • What do you suppose is most important? • What organic molecule would you pick? • Hint: It’s going to need to guide the cell…

  4. Of course, DNA! • DNA is the information of a cell. • The “genetic code.” • This needs to be copied over to the new cell. • This stuff “codes for proteins” (like a script) and makes you who you are. Not what DNA actually looks like… DNA in pop culture? http://static.guim.co.uk/sys-images/Film/Pix/pictures/2008/06/30/jurassicpark460.jpg http://www.eyeondna.com/wp-content/uploads/2007/11/mrdna.jpg

  5. Cell Division and DNA • There are three major methods for cell division: • Binary Fission • Mitosis • Meiosis Momentarily… Mainly Prokaryotes Soon Eukaryotes

  6. Binary Fission: A View Animated Form http://upload.wikimedia.org/wikipedia/commons/d/d2/Binary_fission_anim.gif

  7. Cell Division in Prokaryotes • Called “Binary Fission.” • Simple • Ring of DNA copies. • New membrane grows across the cell, pinching it “like a long balloon squeezed in the middle.” • Holt: Biology • 2 cells result, both with the same DNA. • Unless something happened.

  8. Eukaryotic Cell Division • For eukaryotes, things are different. We don’t just have DNA. Eukaryotes have… • Begins with a “C…” • Ends in a “hromatin…” • Right, eukaryotes have chromatin: http://www.reading.ac.uk/cellmigration/chromatin.jpg

  9. Chromatin • Chromatin is made of two things: • DNA • Proteins (called histones) • The DNA is wrapped around the histones.

  10. What chromatin does… • Chromatin in the nucleus is a lot like a bunch of loose fishing line. • It’s a bunch of long, thin, invisible strands. http://thumb1.shutterstock.com.edgesuite.net/display_pic_with_logo/7096/7096,1231099264,4/stock-photo-a-spool-of-monofilament-fishing-line-macro-shot-showing-all-the-dirt-and-lint-all-over-the-strands-22762768.jpg

  11. But then… • When pieces of chromatin condense, they become visible under the microscope. • The condensed chromatin pieces are now called chromosomes. • Trivia: Called chromosomes because they absorb dye easily. http://www.koifishcareinformation.com/wp-content/uploads/2010/02/fishing-line-pond-protection-for-koi.jpg

  12. How big are we talkin’? • http://learn.genetics.utah.edu/content/begin/cells/scale/ • Scale of the Universe

  13. Humans Mom Dad . . . . . . • We have 46 totalchromosomes (in each cell). • Arranged in 23 pairs– 2 copies of each. • One chromosome in each pair is from your mother, one is from your father. • These are called homologous chromosomes. • They may not be exactly the same, but they carry the same types of information. • Like eye color, perhaps.

  14. Humans • Our body cells have a diploid arrangement of chromosomes. • Diploid is word that describes an arrangement in which you have pairs of chromosomes. • We describe diploid chromosome arrangements with the term 2n. • n = how many chromosome types we have. • In humans, n = 23. 2(23) = 46 total chromosomes. • Example: A pair of shoes is much like a pair of chromosomes in a diploid arrangement. Same shoe, but slightly different (left vs. right).

  15. Chromosomes: A Diagram View From Mom From Dad Homologous Chromosomes http://www.macroevolution.net/images/sister-chromatids-275.jpg

  16. Chromosomes: A “Real” View

  17. Other Organisms • Dog: 78 Chromosomes (39 pairs) • Orangutan: 48 Chromosomes (24 pairs) • Mouse: 40 Chromosomes (20 pairs) • Strawberry: 56 Chromosomes (7 groups of 8 - octoploid) • Adders-tongue fern: 1200 or 1260 Chromosomes

  18. Mule • Horse + Donkey http://cloud.equinenow.com/140171_1/mare_mule_horse.jpg

  19. Liger • ♂ Lion, ♀ Tiger http://2.bp.blogspot.com/__jinAaXs1i4/TGzaZyBwtmI/AAAAAAAAAI8/bMYSAFod7bw/s640/Liger4.jpg

  20. Tiglon • ♂ Tiger, ♀ Lion http://www.metrolic.com/wp-content/uploads/2010/09/Tiglon20.jpg

  21. Zedonk • Donkey/Zebra http://4.bp.blogspot.com/_p5mAt9Tofmg/TFf_sh1ENTI/AAAAAAAAAt4/ZM0AlU4z9gU/s320/zedonk+trimmed.jpg

  22. Okapi • NOT a hybrid! (related to giraffes) http://upload.wikimedia.org/wikipedia/commons/1/18/Okapi2.jpg

  23. Platypus (also not a hybrid) • Monotreme (egg-laying mammal) with 10 sex chromosomes and DNA features characteristic of mammals, birds, and reptiles (!). http://1.bp.blogspot.com/-2zq5eXFKk5E/Tc6GeJUi5fI/AAAAAAAAAro/ad_I1NKNF8c/s1600/Platypus+003.jpg

  24. Karyotyping • Arranging/looking at/analyzing chromosomes is a called making a karyotype(or karyotyping). • Chromosomes are arranged primarily by size and homologous chromosomes are paired. http://www.genomenewsnetwork.org/gnn_images/whats_a_genome/karyotype.gif

  25. Two Types of Chromosomes • Autosomes • The 22 “body” chromosomes. • They’re responsible for non-gender things in the body.

  26. Two Types of Chromosomes • Sex chromosomes • The one pair of chromosomes that contains information linked to gender. • And some stuff not linked to gender. • Two X chromosomes = XX • Female • One X, One Y = XY • Male • Y chromosome is relatively small.

  27. X and Y Chromosomes? • The X chromosome is much larger than the Y. • X carries a lot of genes (140 to be exact), some related to gender, some not. • Y carries only about 40 genes and nearly all are related to being a male. X Chromosome Y Chromosome

  28. So what’s on those chromosomes? • Human Chromosome Map • Human Chromosome Map Pictures

  29. Let’s do some karyotyping… • Visit this website: • http://learn.genetics.utah.edu/content/begin/traits/karyotype/ • You will first just practice karyotyping on this website. • When you are finished, LEAVE YOUR COMPUTERS OUT. • We’re going to discuss some chromosome-based diseases.

  30. Sex Chromosome-Linked Conditions • XX - ♀ • XY - ♂ • XXX - TrisomyX • Female, otherwise healthy. (1 in 1000 females) • XXY - Klinefelter’sSyndrome • Male, reduced sex characteristics, some female characteristics. • XO - Turner’s Syndrome • Female, appear normal but sterile. • XYY • Male, otherwise healthy. (1 in 1000 males)

  31. Aneuploidy • An abnormal number of chromosomes is called aneuploidy. • Trisomy X, Klinefelter’s, and Turner’s are all aneuploidies, as are the conditions we will discuss on the next slides. • Aneuploidies can be autosomal or sex chromosome-linked.

  32. Autosomal Conditions • Trisomy 21 • Three copies of the 21st chromosome instead of two. • 47 total chromosomes instead of 46. • Leads to Down Syndrome. http://kittymowmow.files.wordpress.com/2008/01/whitetigerdeformed1.jpg

  33. Autosomal Conditions • Trisomy 13 • Three copies of the 13th chromosome instead of two. • 47 total chromosomes instead of 46. • Leads to Patau Syndrome. http://myummah.co.za/site/wp-content/uploads/2009/02/image-801.jpg http://www.diagnosticpathology.org/content/figures/1746-1596-2-48-1.jpg

  34. You may be thinking… • If an extra chromosome copy is so harmful, how are females not harmed by having two X-chromosomes? Don’t they have the same information? • While females do have two X chromosomes, one of the two is randomly inactivated early in development (prior to pregnancy). • The chromosome that is turned off is called a Barr Body.

  35. Let’s do some more karyotyping… • Now visit Quia and open the quiz called “Karyotyping” and follow the directions. • You’ll need a different website for this activity. • On this website, just click where the match should go. No dragging. • Linked on my website under University of Arizona – Karyotypingor in the quiz itself. • http://www.biology.arizona.edu/human_bio/activities/karyotyping/karyotyping.html • You’re going to be diagnosing people with chromosomal diseases (or nothing).

  36. Gametes • In somatic cells (non-sex cells), there are 23 pairs of chromosomes, including one pair of sex chromosomes. • You’ve probably already written most of this – just take note of the definition of “somatic cells.” • In sperm and ova (gametes), there are only 23 chromosomes total. • Haploid (1n). • Only one sex chromosome. • Like having only a left shoe instead of a pair of shoes.

  37. GametesOva and Sperm • Ova (eggs) are produced by females. • Made by cells that have XX karyotype. • Therefore,ova always have one X sex chromosome. • Sperm cells are produced by males. • Made by cells that have XY karyotype. • Therefore,sperm could have either one X or one Y sex chromosome.

  38. Class Baby Pictures • And now, let’s take a look at some class baby pictures. • Seriously. • And please thank your parents for cooperating (and keeping this a secret).

  39. Zygote • Your first diploid cell: http://www.alphascientists.org/images/uploads/images/Zygote_1.jpg

  40. Gametes • One sperm and one ovum (each haploid) combine to form a zygote (first cell - diploid). • 23 chromosomes from egg + 23 chromosomes from sperm = 46 chromosomes in zygote. • Like matching a left shoe (sperm) with a right shoe (ovum). http://images-cdn01.associatedcontent.com/image/A6498/649888/150_649888.jpg http://www.ncbi.nlm.nih.gov/bookshelf/picrender.fcgi?book=cell&part=A5406&blobname=ch20f4.jpg

  41. Henry the VIII I even look like I’m an idiot. • Six wives. • Really wanted a son. • Whose “fault” was it?

  42. Exit Ticket • Exit Ticket:Humans have ___ total chromosomes, or ___ pairs of chromosomes. • You must show me your answer on your way out the door.

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