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Genetics and Embryology Discussion

This session focuses on discussing microbiology, karyotypes, and embryology. There will be a reading session from the book "Hot Zone" and the completion of review sheets.

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Genetics and Embryology Discussion

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  1. HONORS Objectives 1/15/2015 WARMUP: Please have a seat and take out your Hot Zone books. Agenda: • Discuss Microbiology Quiz and Hot Zone (pt 1 quiz) • Discuss Karyotypes • Introduce Embryology • Hot Zone Reading Session (if time) HWK: Articles are due on Tuesday (be prepared for 3-4 open note quizzes) Please work on the Review Sheet (this is on my teacher site) Embryology Quest and Review Sheet due Tuesday Locate your textbook- Due on Friday 1/23

  2. Academic Objectives 1/15/2015 WARMUP: Please have a seat and take out your Final Review Sheet and Answers (#10-19) Agenda: • Discuss Microbiology Quiz • Discuss Karyotypes • Introduce Embryology • Final Review Session (time to get ahead on your hwk) HWK: Final Review Packet- due Tuesday Embryology Quest and Embryo Review Sheet due Tuesday Locate your textbook- Due on Friday 1/23

  3. Karyotypes FEMALES MALES

  4. How much DNA do we have? BrainPop- Genetics 23 pairs of chromosomes 23andMe

  5. Klinfelters Syndrome Males who have have an XXY pattern. Physical development: Don’t make as much testosterone as other boys. Tend to be taller, less muscular body, less facial and body hair, and broader hips), larger breasts, weaker bones, and a lower energy level and infertility . 1 of every 500 males has an extra X chromosome, but many don’t have any symptoms. KS

  6. Downs Syndrome Trisomy 21, is a condition in which extra genetic material causes delays in the way a child develops, both mentally and physically. It affects about 1 in every 800 babies born in the United States. Physically- flat facial profile, an upward slant to the eyes, small ears, and a protruding tongue. Age 30 1 in 1,000 Age 351 in 400 Age 40 1 in 100. Downs

  7. Turners Syndrome Girls with Turner syndrome are born with only 1 X or they are missing part of one X chromosome. Girls with Turner syndrome are usually short in height (4 feet 7in.) Heart & kidney problems, over weight, learning disabilities, webbed neck, drooping eyelids and more… Turners affects about 1 in every 2,500 girls.

  8. Overview of Sexual Reproduction • Sexual Reproduction is the combination of genetic information from 2 different organisms • Increases diversity in a population • Sex cells AKA germ cells or gametes • Created By Meiosis • Meiosis is made up of 2 nuclear divisions: • Meiosis I – homologous chromosomes separate • Meiosis II – sister chromatids separate

  9. Meiosis I What happens here?? What happens here?? Interphase Prophase I Metaphase I What type of cell am I?? Anaphase I Telophase I Cytokinesis Images from: http://www.phschool.com/science/biology_place/biocoach/meiosis/teloi.html

  10. Meiosis II Coming from Meiosis I Prophase II Metaphase II Telophase II Anaphase II Cytokinesis Images from: http://www.phschool.com/science/biology_place/biocoach/meiosis/teloi.html

  11. HUMAN GAMETES: • The Human Gametes are… • Sperm – male (23 chromosomes) • Ovum (egg) – female (23 chromosomes) • Gametes are made through a specialized form of meiosis… • Spermatogenesis – formation of sperm • Oogenesis – formation of ova • Gametes are made in the gonads… • Testes in males • Ovaries in females

  12. n=2 sex cell sperm n=2 n=2 2n=4 haploid (n) n=2 n=2 diploid (2n) n=2 meiosis I meiosis II MEIOSIS

  13. SPERM- 4 parts 1 Acrosome– holds powerful enzymes that help sperm enter egg cell Nucleus – 23 chromosomes Midpiece – holds mitochondria (provides energy) Tail – 1 flagellum, allows sperm to ‘swim’ 2 3 4

  14. Spermatogenesis This process begins in puberty, continues until death

  15. Female Anatomy Uterus Ovary Fallopian Tube

  16. OVUM • Large cell with a nucleus =23 chromosomes • Large cytoplasm containing: • Yolk– will be the precursor for blood and reproductive cells, in organisms other than mammals the yolk provides the nutrients for the developing embryo • Organelles – most importantly the mitochondria • Cell membrane – Which contains the rest of the cell • Layer of jelly – surrounds the cell membrane and protects the ovum

  17. Female Reproductive Organ • Fallopian tubes extend from the ovaries to the uterus • They provide the pathway for ovum to reach the uterus • They are the site of fertilization • Uterus receives, retains, nourishes the fertilized ova • The ovariesare composed of sac-like structures • Their job is to produce the ovum (eggs)

  18. The Process of Oogenesis A female is born with a total supply of ovum(eggs) Ability to release eggs begins at puberty and ends at menopause

  19. The Process of Oogenesis Only one primary oocyte goes through meiosis at a time, this occurs once a month If an egg is not fertilized it dies

  20. HONORS Objectives 1/16/2015 WARMUP: .. Agenda: • Finish Embryology • Embryology Review Sheet • Hot Zone Reading Session with remaining time HWK: Articles are due on Tuesday (be prepared for 3-4 open note quizzes) Please work on the Review Sheet (this is on my teacher site) Embryology Quest and Review Sheet due Tuesday Locate your textbook- Due on Friday 1/23

  21. Academic Objectives 1/15/2015 WARMUP: WARMUP: .. Agenda: • Finish Embryology • Embryology Review Sheet • Hot Zone Reading Session with remaining time HWK: Final Review Packet- due Tuesday Embryology Quest and Embryo Review Sheet due Tuesday Locate your textbook- Due on Friday 1/23

  22. Steps From Fertilization to Birth • Fertilization • Zygote • Cleavage • Morula • Blastula • Implantation • Gestation • Gastrula • Embryo • Fetus

  23. Fertilization • Fertilizationor conception – ovum and sperm combining • Ovum has 48 hours from time released to be fertilized • If not fertilized they dissolve (menstruation occurs)

  24. Fertilization • At the same time, when a man ejaculates… • About 300 million sperm are deposited in the vagina • Only about 300 thousand reach the top of the uterus • And only 300 make it to the top of the Fallopian tube where fertilization takes place • Sperm, have approximately 48 hours before they die

  25. Fertilization • Sperm breaks through layers meeting and fusing with the membrane surrounding the ovum • Sperm must burrow through layers of protective cells when they reach the ovum

  26. The steps of fertilization Sperm contacts jelly layer and the egg cell recognizes the proteins on sperm cell Acrosome breaks and releases enzymes that break the jelly layer around the ovum Sperm forms a tube that pushes to the cell membrane Tube fuses with cell membrane Sperm nucleus moves into the egg, tail stays behind Fertilization – officially occurs when the 2 nuclei fuse

  27. FERTILIZATION Within ~20 seconds a reaction occurs to form fertilization membrane – blocks additional sperm from entering the cell Why would the entry of multiple sperm be bad?

  28. FERTILIZATION • A new cell called the zygotehas been formed • Diploid • Will enter mitosis • Genetic material will be copied millions of times and it will divide over and over again

  29. HONORS Objectives 1/16/2015 WARMUP: .. Agenda: • Finish Embryology • Embryology Review Sheet • Hot Zone Reading Session with remaining time HWK: Articles are due on Tuesday (be prepared for 3-4 open note quizzes) Please work on the Review Sheet (this is on my teacher site) Embryology Quest and Review Sheet due Tuesday Locate your textbook- Due on Friday 1/23

  30. Academic Objectives 1/15/2015 WARMUP: WARMUP: .. Agenda: • Finish Embryology • Embryology Review Sheet • Hot Zone Reading Session with remaining time HWK: Final Review Packet- due Tuesday Embryology Quest and Embryo Review Sheet due Tuesday Locate your textbook- Due on Friday 1/23

  31. Stem Cells • Cells with the potential to develop into many different cell types in the body. • Stem cells are unspecialized(they do not have a job in the body). • Stem cells can divide and renew for long periods of time.

  32. Cleavage • Zygotefirst divides after about 24 hours after fertilization = cleavage • After 3 days a solid ball of cells form=the morula • Cells in the morula divide into hundreds of cells and form a ring around a fluid filled cavity= blastocyst • The blastocyst embedsitself in the uterine lining - implantation

  33. Cleavage – cell cycle without growth Solid ball of cells Fertilized egg Implantation (blastula implants in the endometrium of the uterus) Hollow ball of cells AKA: blastula

  34. Gestation • Pregnancy or gestation begins at implantation • After implantation cells begin to differentiate or gradually change into specific cell types • The 9 month period of pregnancy is divided into three trimesters

  35. Embryo Or Fetus? • What’s the difference between an embryo and a fetus?

  36. Gastrulation • Gastrulation= the period of time when cells differentiate into three major germ layers: • Endoderm– digestive tract, respiratory system, liver, pancreas • Mesoderm – muscles, tissues, bones • Ectoderm – skin, brain, nervous system • Results in a Gastrula=a hollow ball with 3 distinct germ layers

  37. Important Membranes of the Fetus • Amnion- forms the amniotic sac • surrounds and protects developing embryo • Yolk sac – provides nutrition & site of formation of first blood & reproductive cells • Chorion- Surrounds all other membranes • Chorionic villi –forms the placenta See figure 52-9

  38. The Placenta • The placenta creates an area of exchange between the mother and baby • Blood of mother and baby never mix • Constant exchange of nutrients, gases, pathogens, drugs and other substances • Fetus is attached to the placenta by the umbilical chord

  39. SPERMATOGENISIS: Word Bank: differentiation, meiosis I, mitosis, meiosis II, sperm spermatogonium1* spermatocyte spermatid, 2* spermatocyte ovum, polar body, oogonium, 1* oocyte 2* oocyte Spermatide 1* Spermatocyte Spermatogonium MITOSIS MEIOSIS I 2* Spermatocyte MEIOSIS II DIFFERENTIATION Spermatogonium Sperm OOGENISIS Polar Body 1* Oocyte Polar Body Oogonium MITOSIS MEIOSIS I MEIOSIS II DIFFERENTIATION 2* oocyte oogonium Otid Ovum

  40. First Trimester • Month 1 • Fertilization, Cleavage, Implantation, Gastrulation • HCG(hormone) is produced • Month 2 & Month 3 • Nervous system is the first organ system to form. • Heart develops and begins beating • All other organ systems begin to form. • Placenta forms and the umbilical cord connects mother and embryo.

  41. First Trimester

  42. Second Trimester 21 wks 28 wks • Month 4, 5 & 6 • Accessory organs form. (Nails, eyelashes, eyebrows) • Baby moves (can suck its thumb, kick and punch) • Doctors can tell if it is a boy or girl • Mother can feel baby moving • Skin is covered by soft hair • lungs begin to develop

  43. Second Trimester

  44. Third Trimester • Months 7, 8 and 9 • Organs continue to develop • Starts to gain fat under skin • Size increases rapidly • The immune system develops • Can sense light and darkness and react to sounds • Labor will be triggeredby the release of a hormone called oxytocin 36 wks

  45. Labor • Dilation • Oxytocin is released causing: • Contractions to begin • Cervix to dilate • baby’s head pushed down • amniotic sac bursts (water breaks) • Expulsion • Cervix is fully dilated (10cm) • Contractions occur every 1-2 min. • The child is delivered • Afterbirth • The placenta (afterbirth) is delivered

  46. Premature Birth • A baby can survive if born 23 weeks early (during 2nd trimester) • Increased risk of developmental and medical problems • 1 in 10 babies are premature • Causes: • Rupture of amniotic sac • Certain infections • Weak cervix (from previous pregnancy) • Uterine abnormalities • Previous premature delivery • Substance abuse • Malnutrition

  47. Twins • Monozygotic twins • They are genetically identical • Occurs when the fertilized egg splits completely in half during cleavage • Dizygotic twins • Non-identical twins • Occurs when two or more eggs are released by the mother at a time and are fertilized by two different sperm cells Fraternal Twins Identical Twins

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