1. BIO1140 Introduction to Cell Biology
BIO1140 Lab 5 Meiosis
BIO1140 Introduction to Cell Biology

2. BIO1140 Introduction to Cell Biology
Objectives
Identify selected meiotic phases and their characteristics
Microsporogenesis in Lilium
Meiosis in Ascaris.
Identify various stages during micro-sporogenesis.
Study spermatogenesis in the rat testis and oogenesis in the rabbit ovary.
Capture digital images of assigned material and draw a biological drawing based on those photos.
BIO1140 Introduction to Cell Biology

3. Separation of homologous  chromosomes Separation of chromatids
Meiosis
Reductive division of cells
Diploid cell (2n)
Pre-mieotic interphase
Duplication of chromosomes
tetraploid cell (4n)
Separation of homologous  chromosomes
First division (2n)
Separation of chromatids
Second division haploid cells (n)

4. BIO1140 Introduction to Cell Biology
I- Meiosis in plants
Lily microsporogenesis
Formation of male gametes (pollen) in Anther
Identify stages and structures using prepared slides
visit also website:
BIO1140 Introduction to Cell Biology

5. pa f Meiosis in plants anther pc e tapetum
Meiosis in Lillium anther (early prophase):
e: epidermis; f: filament; pa: parenchyme; pc: pollen cell precursor (prophase)
pollen sacs (microsporangia)

6. BIO1140 Introduction to Cell Biology
II- Meiosis in Animals
Meiosis in Ascaris
BIO1140 Introduction to Cell Biology

7. BIO1140 Introduction to Cell Biology
Selected stages
Sperm entrance
Primary oocyte arrested in prophase 1 (no shell)
Penetration of the spermatozoid (sp) triggers the egg nucleus (n) to continue meiosis sp n
BIO1140 Introduction to Cell Biology

8. BIO1140 Introduction to Cell Biology
Selected stages
Metaphase I
Presence of shell (s)
Chromosomes lined up at equator (c)
No polar body
Male pronucleus visible (p) at center of cell p s c
BIO1140 Introduction to Cell Biology

9. BIO1140 Introduction to Cell Biology
Selected stages
Anaphase I
Homologous chromosomes separate and are moving to opposite spindle poles
BIO1140 Introduction to Cell Biology

10. BIO1140 Introduction to Cell Biology
Selected stages
Metaphase II
Similar to metaphase I but with the presence of a polar body (pb) in the perivitelline space (ps) pb ps
BIO1140 Introduction to Cell Biology

11. BIO1140 Introduction to Cell Biology
Selected stages
Anaphase II
Centromeres split
chromatids separate then move to cell poles
BIO1140 Introduction to Cell Biology

12. BIO1140 Introduction to Cell Biology
Selected stages
Interphase
Following telophase II, haploid male and female pronuclei (pn) in interphase prior to fusion (fertilization).
Second polar body expelled (not visible here)
The resulting zygote (2n) continues to divide by mitosis. pn
BIO1140 Introduction to Cell Biology

13. BIO1140 Introduction to Cell Biology
Selected stages
Mitotic cleavage of the embryo
Stop after this slide
BIO1140 Introduction to Cell Biology

14. BIO1140 Introduction to Cell Biology
Meiosis in mammals
Gametogenesis in rat testis and rabbit ovary
You’ll be assigned one species for your lab report
Observe both species (exam material)
Resume talk here
BIO1140 Introduction to Cell Biology

15. Rat (Rattus norvegicus) spermatogenesis
Occurs within the walls of the seminiferous tubules
Recognize stages
by position (immature stages near outside of tubule, mature stages near lumen).
See for details
You should follow the link and show students the main structures seen on testis CS – Or use next slide
BIO1140 Introduction to Cell Biology

16. BIO1140 Introduction to Cell Biologysc bl ps st sg ss sp L
bl: basal lamina, L: lumen of the tubule, sc: sertoli cell nucleus, sg: spermatogonia, ps: primary spermatocyte, ss: secondary spermatocyte, sp: sperm cells (cross section), st: spermatids
BIO1140 Introduction to Cell Biology

17. Rabbit (Sylvilagus floridanus) oogenesis
Identify maturation stages of the follicles depending on position in the ovary, number of layers of follicular cells and presence of fluid-filled cavities
See for details
BIO1140 Introduction to Cell Biology

18. BIO1140 Introduction to Cell Biology
Primordial follicle
Primordial follicle (pf) are located underneath the ovary epithelium (ep)
Surrounded by one layer of squamous (=flat) follicular cells
ic: interstitial cells pf ic ep
BIO1140 Introduction to Cell Biology

19. Primary unilaminar follicle
Located deeper in the ovary
Surrounded by one layer of cuboidal follicular cells (fc)
Contains a primary oocyte (po)
n: oocyte pronucleus po n fc
BIO1140 Introduction to Cell Biology

20. Growing follicle (primary multilaminar):
Slightly deeper in the ovary
Surrounded by several layers of follicular cells (fc)
Contain primary oocyte (dash lines).
n: oocyte pronucleus fc n
BIO1140 Introduction to Cell Biology

21. Mature or Graafian Follicle
Largest follicle
Many layers of follicular cells (fc)
One big or several fluid-filled cavities (fca)
Contains secondary oocyte (so) stopped in metaphase II = mature oocyte
Comes near to ovarian epithelium prior to ovulation so
fca fc
BIO1140 Introduction to Cell Biology

22. BIO1140 Introduction to Cell Biology
Lab5 Report: 3 pages
Page 1: Title page Page 2: Annotated picture printout Page 3: Biological drawing You must take 2 pictures during the lab that you will use for your lab report:
Report instructions
BIO1140 Introduction to Cell Biology

23. Rabbit ovary (Sylvilagus floridanus)
Picture 1: Global view at 10x showing follicles at various stages (at least 2 stages, such as primordial and unilaminar) plus (if possible) ovarian epithelium.
Picture 2: close-up view at 40x of picture 1 showing a unilaminar or multilaminar follicle.
(picture 2 must be a subset of picture 1, taken at 40x)
BIO1140 Introduction to Cell Biology

24. Rat testis (Rattus norvegicus)
Picture 1 : Global view at 10x of a cross section showing several seminiferous tubules.
Picture 2: magnified view at 40x of picture 1 showing both the lumen and the periphery of one seminiferous tubule.
(picture 2 must be a subset of picture 1, taken at 40x)
BIO1140 Introduction to Cell Biology

25. BIO1140 Introduction to Cell Biology
Lab5 Report
Annotated picture (picture 1): use template file (download on lab website) to print picture (grayscale), then label either on computer or by hand.
Biological drawing (picture 2): read instructions in lab manual appendix. Remember: no shading, stippling, patterns, all lines have same thickness.
Follow biological drawing instructions relative to labels and caption for both pages
BIO1140 Introduction to Cell Biology

26. BIO1140 Introduction to Cell Biology
Lab5 Report
Take pictures showing the required view and structures then call one of your TAs so they can check the content of your pictures and evaluate their quality
Do not leave without saving (and/or ing) the pictures or you won’t have any material for your assignment (penalty will apply)
Add a scale bar AND a caption to both the printout and the drawing pages
BIO1140 Introduction to Cell Biology

27. Lab 5 Report and evaluation
Available documents (lab manual and/or Lab web):
List of structures you can observe on sections - use this list to label your drawing.
Instruction file for lab5 and biological drawing.
Guide Biolabo: labeling, scale bar and caption sections of the “Biological drawings” chapter.
Don’t forget:
Tech skill marks: 15% of lab5 mark (cleanliness, microscope use and quality of pictures taken).
BIO1140 Introduction to Cell Biology

28. Corrected lab5 reports and Final lab marks
Corrected lab5 reports will be available to pick up about 3 weeks after your lab (date and location will be announced on website).
All lab marks (including the final mark) will be posted on the lab website (soon).
Corrector office hours are posted on the contact page of website. If the corrector for your section is not listed, contact your TA.
BIO1140 Introduction to Cell Biology

29. FINAL EXAM: SATURDAY APRIL 11th 1PM-2:30PM
Contact coordinator today if you have a conflict with another course or exam.
Exam rooms: see final exam page of website
Materiel covered: all Lab manual content (including appendices), lab experiments, specimens (including Lab5 structure list) and lab reports.
Format: multiple choice, short answers and identification of structures on pictures. similar to prelab quizzes.
BIO1140 Introduction to Cell Biology