bio1140 lab 5 meiosis
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BIO1140 Lab 5 Meiosis. 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. - PowerPoint PPT PresentationTRANSCRIPT
BIO1140 Lab 5: Meiosis
Objectives of the lab
• 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
MeiosisReductive division of cells
Diploid cell (2n)
Pre-mieotic interphaseDuplication of chromosomes
tetraploid cell (2x2n)
First division (2n)
Second division haploid cells (n)
Separation of homologous chromosomes
Separation of chromatids
I- Meiosis in plants
BIO1140 Introduction to Cell Biology
Lily microsporogenesis• Formation of male gametes (pollen) in Anther• Identify stages and structures using prepared slides • visit also website:
http://www.iasprr.org/old/iasprr-pix/lily/male.shtml
tapetum
pollen sacs (microsporangia)
e
e: epidermis; f: filament; pa: parenchyme; pc: pollen cell precursor (prophase)
pc
f
pa
Meiosis in Lillium anther (early prophase):
anther
Meiosis in plants
II- Meiosis in Animals
BIO1140 Introduction to Cell Biology
Meiosis in Ascaris
Selected stages
BIO1140 Introduction to Cell Biology
Sperm entrancePrimary oocyte arrested in prophase 1 (no shell)Penetration of the spermatozoid (sp) triggers the egg nucleus (n) to continue meiosis
sp
n
Selected stages
BIO1140 Introduction to Cell Biology
Metaphase IPresence of shell (s)Chromosomes lined up at equator (c)No polar bodyMale pronucleus visible (p) at center of cell
s c
p
Selected stages
BIO1140 Introduction to Cell Biology
Anaphase IHomologous chromosomes separate and are moving to opposite spindle poles
Selected stages
BIO1140 Introduction to Cell Biology
Metaphase IISimilar to metaphase I but with the presence of a polar body (pb) in the perivitelline space (ps)
pb
ps
Selected stages
BIO1140 Introduction to Cell Biology
Anaphase IICentromeres splitchromatids separate then move to cell poles
Selected stages
BIO1140 Introduction to Cell Biology
InterphaseFollowing 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
Selected stages
BIO1140 Introduction to Cell Biology
Mitotic cleavage of the embryo
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)
BIO1140 Introduction to Cell Biology
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 http://www.ouhsc.edu/histology/ for details
BIO1140 Introduction to Cell Biology
BIO1140 Introduction to Cell Biology
sc
sg
ps
ss
st
L
bl
sp
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
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 http://www.ouhsc.edu/histology for details
BIO1140 Introduction to Cell Biology
Primordial follicle
BIO1140 Introduction to Cell Biology
Primordial follicle (pf) are located underneath the ovary epithelium (ep)Surrounded by one layer of squamous (=flat) follicular cells ic: interstitial cells
pf
ep
ic
Primary Unilaminar Follicle
BIO1140 Introduction to Cell Biology
Located deeper in the ovarySurrounded by one layer of cuboidal follicular cells (fc)Contains a primary oocyte (po)n: oocyte pronucleus
fc
po
n
Growing Follicle (Primary Multilaminar):
BIO1140 Introduction to Cell Biology
Slightly deeper in the ovarySurrounded by several layers of follicular cells (fc)Contain primary oocyte (dash lines).n: oocyte pronucleus
nfc
Mature or Graafian Follicle
BIO1140 Introduction to Cell Biology
Largest follicleMany layers of follicular cells (fc)One big or several fluid-filled cavities (fca)Contains secondary oocyte (so) stopped in metaphase II = mature oocyteComes near to ovarian epithelium prior to ovulation
so
fcafc
Lab5 Report: 3 pages
BIO1140 Introduction to Cell Biology
Page 1: Title pagePage 2: Annotated picture printoutPage 3: Biological drawing
You must take 2 pictures during the lab that you will use for your lab report with the following requirements:
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
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
Pictures for lab report
BIO1140 Introduction to Cell Biology
Take picture 1 under the 10x objective
Take a second picture at 40x (picture 2)
Draw picture 2
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
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 emailing) 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
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
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
BIO1140 Introduction to Cell Biology
FINAL EXAM: SATURDAY APRIL 7th 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.
• See the FINAL page on the lab website for more info.