Explain the following concepts: Asexual – sexual reproduction. Mitosis Meiosis Diploid – Haploid Gametes Fertilization Zygote Syngamy Blastocy

• ALFRED CIOFFI

• CATHOLIC PRIEST, ARCHDIOCESE OF MIAMI

• DOCTORATE IN MORAL THEOLOGY, GREGORIAN UNIVERSITY, ROME, ITALY

• DOCTORATE IN GENETICS, PURDUE UNIVERSITY, INDIANA

• ASSOCIATE PROFESSOR, BIOLOGY AND BIOETHICS

• DIRECTOR, INSTITUTE FOR BIOETHICS

BIOMEDICAL ETHICS

Introduction

• PRESENTATIONS

• THINK

• RESPECT

• HONOR CODE

• ON TIME

• QUIZZES

• TAKE NOTES

• AVERAGE

CANVAS

HUMAN BIO-ETHICS​: evidence-based

• BEGINNING OF LIFE​

• HEALTHCARE​

• END OF LIFE

BIO-ETHICS

PRINCIPLED

UTILITARIAN

or…

• SEXUAL REPRODUCTION

• EARLY EMBRYONIC DEVELOPMENT

• ONTOLOGICAL STATUS OF HUMAN EMBRYO

SEXUAL REPRODUCTION: INVOLVES FERTILIZATION

FERTILIZATION: INVOLVES FUSION OF GAMETES

AT FERTILIZATION THE DIPLOID NUMBER (2n) IS RESTORED

GAMETES = SEX CELLS (SPERM & OVA), PRODUCED BY MEIOSIS

FIRST, A REVIEW OF MITOSIS

b

d

c

a

chromatin

2n

2n

b

d

c

a

chromatin

2n

2n

X

X X

X

2b

1a

1b

2a

chromatin

2n

2n

2b1b 1a

2a

2b1b 1a

2a

1a 1b

2b

2a

2b1b 1a

2a

2a 2b

1b

1a

DNA REPLICATION

SISTER CHROMATIDS

Temporary “4n” stage

2b1b 1a

2a

CELL CYCLE

G = GAP

S = SYNTHESIS

2n

2n

2n

MEIOSIS: DOUBLE CELLULAR SPLIT: ONE CELL -> -> 4 CELLS

• RECOMBINATION (CROSSING OVER)

• FROM DIPLOID NUMBER (2n) -> HAPLOID NUMBER (n) = CHROMATIC REDUCTION

2a

2b 1a

1b

2a

2b

1a

1b

2a2b

1a1b

DNA RECOMBINATION = CROSSING OVER

MEIOSIS = FORMATION OF GAMETES (SEX CELLS), HAPLOID

SPERMATOGENESIS -> SPERM (n) GAMETOGENESIS

OOGENESIS -> OVUM (n)

Primary spermatocyte (2n)

Primary oocyte (2n)

Polar bodies

H. sapiens # OF CHROMOSOMES = 46 = 23 "PAIRS" ONLY IDENTICAL IN FEMALE (XX)

• 22 PAIRS = AUTOSOMES

• 1 PAIR = SEX CHROMOSOMES

THEREFORE, IN HUMANS:

• n = 23 (gametes)

• 2n = 46 (somatic cells)

Seminiferous tubules

Ovarian follicles

VIDEOS OF HUMAN EMBRYONIC AND FETAL DEVELOPMENT

From fertilization to birth 6 minutes https://www.youtube.com/watch?v=7kC6p1twkXk

EGG + SPERM = ZYGOTE

ZYGON (GK) = YOKED OR LINKED

ZYGOTE DNA:

• 50% OF THE GENETIC MATERIAL COMES FROM THE MOTHER

• 50% FROM THE FATHER

0.1 mm 0.005 mm 0.05 mm

= SYNGAMY

Ampulla

DAY 1

DAY 7

Endometrium

ZYGOTE

M O

RU LA

COMPACTION

BLASTOMERES

MALE & FEMALE PRONUCLEI

FIRST CELLULAR DIFFERENTIATION = 2 CELL LAYERS

(INNER CELL MASS)

1 2 3

4 5 6

IMPLANTATION

FURTHER CELLULAR DIFFERENTIATION: 3 GERM LAYERS

( ICM )

GASTRULATION

THIRD WEEK OF EMBRYONIC DEVELOPMNET:

GASTRULA

LONGITUDINAL VIEW CROSS SECTION

NEURAL GROOVE

~ 1 inch

EIGHT WEEKS

EMBRYO FETUS

FETUS

VIDEOS OF HUMAN EMBRYONIC AND FETAL DEVELOPMENT

Conception to birth — visualized | Alexander Tsiaras 10 minutes https://www.youtube.com/watch?v=fKyljukBE70

THEREFORE, REGARDING EMBRYONIC DEVELOPMENT:

CONTINUOUS DEVELOPMENT OF TISSUES, ORGANS AND SYSTEMS

FROM THE ZYGOTE, THROUGH 9 MONTHS, UP TO BIRTH.

AFER BIRTH, DEVELOPMENT CONTINUES, UP TO ADULTHOOD.

ADULTHOOD DEFINED BIOLOGICALLY; MATURITY OF SEXUAL ORGANS.

THAT IS, CAPABLE OF REPRODUCING:

FOR WOMAN: OVULATING MATURE EGGS AND CAPABLE OF SUSTAINING A PREGNANCY

FOR MAN: PRODUCTION OF COMPETENT SPERM AND CAPABLE OF SEXUAL INTERCOURSE