Copy of C9 - Reproduction & Development NN PDF

CHAPTER 9 REPRODUCTION AND DEVELOPMENT (Hours: 3L + 9T)  CHAPTER 9: REPRODUCTION AND DEVELOPMENT 9.1 Sexual Reproduction in Flowering Plants 9.2 Human Reproductive System 9.3 Fertilization And Foetal Development 9.4 Roles of Hormones During Pregnancy and Parturition 9.5 Growth P...

CHAPTER 9 REPRODUCTION AND DEVELOPMENT (Hours: 3L + 9T)  CHAPTER 9: REPRODUCTION AND DEVELOPMENT 9.1 Sexual Reproduction in Flowering Plants 9.2 Human Reproductive System 9.3 Fertilization And Foetal Development 9.4 Roles of Hormones During Pregnancy and Parturition 9.5 Growth Patterns in Human and Plants UPS PSPM 1 - 16 marks 2  LEARNING OUTCOMES 9.1 Sexual Reproduction in Flowering Plants a) State and define the terminologies involved in gamete formation in flowering plants (C1): i. male gamete: microsporangium/pollen sac, microsporocyte/microspore mother cell, microspore, tetrad, pollen grain/male gametophyte, generative cell, tube cell, ii. Female gamete: megasporangium, megasporocyte/megaspore mother cell, megaspore, female gametophyte/embryo sac, antipodal cell, polar nuclei, egg cell, synergid cell. b) Overview the development of a pollen grain and formation of male gamete (C1). c) Overview the development of ovule, embryo sac and formation of female gamete (C1). d) Overview double fertilisation in the formation of seed (C1). 3 Introduc tion Sexual Reproduction in Flowering Plants Sexual reproduction is the creation of offspring by the fusion of gametes to form a zygote. Gametes are haploid (formed by meiosis). ⮚ Ovum (egg) is the female gamete. ⮚ Sperm is the male gamete. Zygote is diploid, divides by mitosis to form new individual. 4 Introduc tion Sexual Reproduction in Flowering Plants Sexual reproduction in plants involves the alternation of two generations (sporophyte & gametophyte generations) ⮚ sporophyte generations are the diploid plants that produces haploid spores ⮚ gametophyte generations are haploid plants that produces haploid gametes For angiosperms, the gametophytes develop within the flower. 5 Introduc tion Life cycle of a flowering plant 6 Learning Outcomes: 9.1 a) State and define the terminologies involved in gamete formation in flowering plants: Reproductive structure Flowers are reproductive structures of flowering plants. Complete flowers have four floral organs ⮚ sepals, ⮚ petals, ⮚ stamens ⮚ carpels All are arranged in four whorls, attached to the receptacle at the end of a stem. 7 Learning Outcomes: 9.1 a) State and define the terminologies involved in gamete formation in flowering plants: Sepals: - the outermost floral parts - usually green (modified leaves) - enclose & protect a floral bud - whorl of sepals is called a calyx 8 Learning Outcomes: 9.1 a) State and define the terminologies involved in gamete formation in flowering plants: Petals: - generally more brightly coloured - broad, flat and thin - attract insects and other pollinators - whorl of petals is called a corolla 9 Learning Outcomes: 9.1 a) State and define the terminologies involved in gamete formation in flowering plants: Stamen: - the male reproductive organ - consists of the anther (with chambers where pollen grains /male gametophytes develop) and the filament (stalk which holds the anther) 10 Learning Outcomes: 9.1 a) State and define the terminologies involved in gamete formation in flowering plants: Carpel: - the female reproductive organ - consists of the stigma, style and ovary Stigma: sticky tip of carpel that serves as the receptive surface for pollen grains Style: neck portion of carpel that connects the stigma to the ovary Ovary: contains the ovule in which the embryo sac/ female gametophyte develops 11 Learning Outcomes: 9.1 a) State and define the terminologies involved in gamete formation in flowering plants: Male Reproductive Organ Terminologies Definition 1. Microsporangium One of the chambers of an anther (or a male cone) / pollen sac in which pollen is produced 2. Microsporocyte / A diploid cell in microsporangium that divide by microspore meiosis to give rise to 4 haploid microspores mother cell 3. Microspore A small haploid spore from a heterosporous plant species that develops into pollen grain 12 Learning Outcomes: 9.1 a) State and define the terminologies involved in gamete formation in flowering plants: Male Reproductive Organ Terminologies Definition A group of 4 haploid microspores 4. Tetrad produced at the end of the second meiotic division 5. Pollen grain / A structure containing generative cell immature & tube cell when a microspore divides male by mitosis gametophyte 6. Generative One of the two cells in a pollen grain cell which divides by mitosis to form 2 non-motile sperm One of the two cells in a pollen grain 7. Tube cell produced when microspore divides by mitosis 13 Learning Outcomes: 9.1 a) State and define the terminologies involved in gamete formation in flowering plants: Female Reproductive Organ Terminologies Definition 1. Megasporangium A structure of ovule where megaspores are produced. 2. Megasporocyte / A diploid cell in megaspore mother megasporangium that cell divides by meiosis to give rise to 4 haploid microspores 3. Megaspore A large haploid spore from a heterosporous plant species that develops into embryo sac / female gametophyte 14 Learning Outcomes: 9.1 a) State and define the terminologies involved in gamete formation in flowering plants: Female Reproductive Organ Terminologies Definition 4. Embryo sac / A structure that develops in the ovule containing 8 nuclei female formed by mitotic division of the surviving megaspore. gametophyte 5. Egg cell The mature, unfertilized, non-motile female reproductive cell 6. Synergid cells The two haploid cells in the embryo sac of flowering plants that are closely associated to the egg cell 15 Learning Outcomes: 9.1 a) State and define the terminologies involved in gamete formation in flowering plants: Female Reproductive Organ Terminologies Definition 7. Antipodal cells Three haploid cells in the embryo sac that are situated at the opposite end to micropyle 8. Polar nuclei Two haploid nuclei in the center of embryo sac which fuse with a male gamete to form a triploid cell 16 Learning Outcomes: b) Overview the development of a pollen grain and formation of male gamete The development of a pollen grain & formation of male gamete. Occur within the anther Each anther has 4 pollen sacs (microsporangia) 17 Learning Outcomes: b) Overview the development of a pollen grain and formation of male gamete 18 Learning Outcomes: b) Overview the development of a pollen grain and formation of male gamete 19 Learning Outcomes: c) Overview the development of ovule, embryo sac and formation of female gamete 20 Learning Outcomes: c) Overview the development of ovule, embryo sac and formation of female gamete 21 Learning Outcomes: c) Overview the development of ovule, embryo sac and formation of female gamete 22 Learning Outcomes: c) Overview the development of ovule, embryo sac and formation of female gamete THE DEVELOPMENT OF OVULE, EMBRYO SAC AND FORMATION OF FEMALE GAMETE 23 Learning Outcomes: c) Overview the development of ovule, embryo sac and formation of female gamete Embryo sac (female gametophyte) 7 cells with 8 nuclei: 3 cells near the micropyle, 1 egg cell (female gamete) 2 synergid cells (flank the egg) opposite end of embyo sac, 3 antipodal cells (unknown function) centre of embryo sac 2 polar nuclei (in a central cell of embryo sac) 24 Learning Outcomes: c) Overview of double fertilization in the formation of seed. Double fertilization in the formation of seed After pollination, a pollen grain absorbs water and germinates Tube cell produces a pollen tube that grows down within the style within the carpel towards the ovary. As the pollen tube elongates, the generative cell divides by mitosis forming 2 sperms (male gametes). Now, the pollen grain has become mature gametophyte. The pollen tube carries the 2 sperms as it moves. 25 Learning Outcomes: c) Overview of double fertilization in the formation of seed. Double fertilization in the formation of seed After reaching the ovary, the pollen tube penetrates the micropyle and discharges the 2 sperms into the embryo sac. Allowing double fertilization. ⮚ One sperm fertilizes the egg to form a diploid zygote, the other sperm fuses with the 2 polar nuclei in the large central cell to form a triploid (3n) cell. 26 Learning Outcomes: c) Overview of double fertilization in the formation of seed. Double fertilization in the formation of seed After double fertilization, i. the ovule matures into a seed ii. the diploid zygote develops into embryo iii. the triploid cell develops into endosperm (tissue rich in starch and other food reserves that nourish the developing embryo). 27 Learning Outcomes: c) Overview of double fertilization in the formation of seed. 28 Learning Outcomes: c) Overview of double fertilization in the formation of seed. Formation of seed After fertilisation: ⮚ Ovule 🡺 seed ⮚ Ovary 🡺 fruit In ovule: ⮚ Zygote (2n) 🡺 embryo ⮚ Triploid cell (3n) 🡺 endosperm Embryo divides and differentiates into multicellular embryo forming: plumule, radicle & cotyledon Endosperm tissue rich in starch & other food reserves that nourish the developing embryo. 29  LEARNING OUTCOMES 9.2 Human Reproductive System a) Overview male reproductive organ (testes) and the structure of spermatozoa (C1). b) Explain the structure of spermatozoa (C3). c) Explain the role of hormones in spermatogenesis: Gonadotropin-Releasing Hormone (GnRH), Luteinizing Hormone (LH), Follicle-Stimulating Hormone (FSH) and Testosterone (C3). d) Explain the stages of spermatogenesis and its hormonal control (C3). 30 Introduc tion 31 Learning Outcomes: 9.2 a) Overview male reproductive organ (testes) and the structure of spermatozoa 32 Learning Outcomes: 9.2 a) Overview male reproductive organ (testes) and the structure of spermatozoa Male Reproductive Organ : Testes The human’s male internal reproductive organ consists of gonads that produce sperm and reproductive hormones. The male gonads is testes, that produce sperm in tubes called seminiferous tubules. 33 Learning Outcomes: 9.2 b) Explain the structure of spermatozoa Spermatozoa The human’s male internal reproductive organ consists of gonads that produce sperm and reproductive hormones. The male gonads is testes, that produce sperm in tubes called seminiferous tubules. 34 Learning Outcomes: 9.2 b) Explain the structure of spermatozoa Structure of a spermatozoa Head: contains haploid nucleus tipped with acrosome Neck: connected the head to the body of sperm. Contain two centrioles 35 Learning Outcomes: 9.2 b) Explain the structure of spermatozoa Structure of a spermatozoa Midpiece: Containing large number of mitochondria Nucleus : haploid. Covered by the acrosome Acrosome: large vesicle that differentiates from the Golgi body. Contain enzymes that help the sperm penetrate the egg 36 Learning Outcomes: 9.2 b) Explain the structure of spermatozoa Structure of a spermatozoa Tail (flagellum): Mitochondria 9+2 arrangement of microtubules Spiral shape provide ATP for the for motility or locomotion movement of the flagellum. 37 Learning Outcomes: 9.2 c) Explain the role of hormones in spermatogenesis: Gonadotropin-Releasing Hormone (GnRH), Luteinizing Hormone (LH), Follicle-Stimulating Hormone (FSH) and Testosterone (C3). Role of hormones in spermatogenesis 38 Learning Outcomes: 9.2 c) Explain the role of hormones in spermatogenesis: Gonadotropin-Releasing Hormone (GnRH), Luteinizing Hormone (LH), Follicle-Stimulating Hormone (FSH) and Testosterone (C3). Role of hormones in spermatogenesis 39 Learning Outcomes: 9.2 c) Explain the role of hormones in spermatogenesis: Gonadotropin-Releasing Hormone (GnRH), Luteinizing Hormone (LH), Follicle-Stimulating Hormone (FSH) and Testosterone (C3). Role of hormones in spermatogenesis 1. The hypothalamus secretes gonadotropin-releasing hormone (GnRH). 2. GnRH stimulates the anterior pituitary gland to secrete both luteinizing hormone (LH) & follicle-stimulating hormone (FSH). 3. LH stimulates Leydig cells / interstitial cells (scattered between the seminiferous tubules) to secrete testosterone. 40 Learning Outcomes: 9.2 c) Explain the role of hormones in spermatogenesis: Gonadotropin-Releasing Hormone (GnRH), Luteinizing Hormone (LH), Follicle-Stimulating Hormone (FSH) and Testosterone (C3). Role of hormones in spermatogenesis 4. Testosterone promotes spermatogenesis in the tubules. 5. Testosterone also acts on Sertoli cells by increasing its responsiveness to FSH. 6. FSH stimulates Sertoli cells (located within seminiferous tubules), to nourish developing sperm. 41 Learning Outcomes: 9.2 c) Explain the role of hormones in spermatogenesis: Gonadotropin-Releasing Hormone (GnRH), Luteinizing Hormone (LH), Follicle-Stimulating Hormone (FSH) and Testosterone (C3). Role of hormones in spermatogenesis 2 negative-feedback mechanisms control sex hormone production in males. Testosterone regulates blood levels of GnRH, FSH and LH through inhibitory effects on the hypothalamus and anterior pituitary gland. i. Testosterone inhibits hypothalamus to reduce the secretion of GnRH. ii. Testosterone also inhibits anterior pituitary gland to reduce the secretion of FSH and LH. 42 Learning Outcomes: 9.2 c) Explain the role of hormones in spermatogenesis: Gonadotropin-Releasing Hormone (GnRH), Luteinizing Hormone (LH), Follicle-Stimulating Hormone (FSH) and Testosterone (C3). Role of hormones in spermatogenesis In addition, the Sertoli cells secretes a peptide hormone called inhibin that inhibits anterior pituitary gland to reduce FSH secretion. Together, these negative feedback circuits maintain androgen levels in the normal range. 43 Learning Outcomes: 9.2 d) Explain the stages of spermatogenesis and its hormonal control (C3). Spermatogenesis Production of mature sperm Continuous process in adult male Takes 65 – 75 days in humans Occurs in seminiferous tubules of testes 44 Learning Outcomes: 9.2 d) Explain the stages of spermatogenesis and its hormonal control (C3). Stages of Spermatogenesis 1. Spermatogonial stem cells arise from mitotic division and differentiation of primordial germ cells. 2. In mature testes, the stem cells divide mitotically to form spermatogonia. 45 Learning Outcomes: 9.2 d) Explain the stages of spermatogenesis and its hormonal control (C3). Stages of Spermatogenesis 3. Each spermatogonium (2n) divides by mitosis to form 2 types of spermatogonia (2n). i. One type remains at the basal membrane ii. Another type differentiate into primary spermatocyte (2n) 46 Learning Outcomes: 9.2 d) Explain the stages of spermatogenesis and its hormonal control (C3). Stages of Spermatogenesis 4. Each primary spermatocyte (2n) undergoes meiosis I to form 2 secondary spermatocytes (n). 5. Each secondary spermatocyte (n) undergoes meiosis II to form 2 spermatids (n). 6. As the spermatids develop, they are being pushed towards the lumen. 7. Spermatids undergoes spermiogenesis (differentiation) to form spermatozoa (sperm cells) (n). 47  LEARNING OUTCOMES 9.2 Human Reproductive System e) Overview female reproductive organ (ovary) and the structure of secondary oocyte (C1). f) Explain the structure of secondary oocyte (C3). g) Explain the role of hormones in female reproductive cycle: Gonadotropin-Releasing Hormone (GnRH), Luteinizing Hormone (LH), Follicle-Stimulating Hormone (FSH), Estrogen and Progesterone (C3). h) Overview the stages of oogenesis (C1). i) Overview female reproductive cycle: ovarian cycle and uterine/menstrual cycle (C1). i. Explain ovarian cycle and its hormonal control (C3). ii. Explain uterine/menstrual cycle and its hormonal control (C3). 48 Learning Outcomes: 9.2 e) Overview female reproductive organ (ovary) and the structure of secondary oocyte. Female Reproductive Organ : Ovary The female gonads are a pair of ovaries that flank the uterus. The outer layer of each ovary is packed with follicles, consisting of an oocyte (partially developed egg) surrounded by support cells. The surrounding cells nourish and protect the oocyte during its formation and development. 49 Learning Outcomes: 9.2 f) Explain the structure of secondary oocyte. Structure of Secondary Oocyte Secondary oocyte is surrounded by zona pellucida (a layer of glycoprotein) that develops a jelly coat. Corona radiata is a layer of granulosa cells surrounding zona pellucida. Granulosa cells supply nutrients to the developing oocyte. During ovulation, secondary oocyte ejects through the ovary wall and into the pelvic cavity. 50 Learning Outcomes: 9.2 g) Explain the role of hormones in female reproductive cycle: Gonadotropin-Releasing Hormone (GnRH), Luteinizing Hormone (LH), Follicle-Stimulating Hormone (FSH), Estrogen and Progesterone. Role of hormones in female reproductive cycle Endocrine Gland & Target Actions Hormones Tissue HYPOTHALAMUS Gonadotropin-releasing Anterior Stimulates the release of FSH & LH hormone (GnRH) pituitary ANTERIOR PITUITARY Follicle-stimulating hormone Ovary Stimulates development of follicles (FSH) and secretion of estrogen Stimulates the final maturation of Luteinizing hormone (LH) Ovary follicle, ovulation and development of corpus luteum. OVARIES Estrogen / estradiol Uterus Stimulates thickening of endometrium. Progesterone Uterus Maintain the thickness of endometrium. 51 Learning Outcomes: 9.2 h) Overview the stages of oogenesis Oogenesis 1. Oogenesis begins in the female embryo with the production of oogonia from primordial germ cells. 2. The oogonia divide by mitosis to form primary oocytes (reside within a small follicle) and begin meiosis, but arrested at prophase I 3. At birth, the ovaries together contain about 1–2 million primary oocytes, of which about 500 fully mature between puberty and menopause. 52 Learning Outcomes: 9.2 h) Overview the stages of oogenesis Oogenesis 4. Beginning at puberty, only one follicle fully matures each month, with its primary oocyte (2n) completing meiosis I forming secondary oocyte (n) and 1st polar body (n). 5. Secondary oocyte (n) continues meiosis II but arrested at metaphase II. 6. Only if a sperm (n) penetrates the secondary oocyte (n) does meiosis II resume. 7. Meiotic divisions involves unequal cytokinesis, with the smaller cells becoming polar bodies that eventually degenerate. 8. As a result, a single mature egg containing a sperm head. 53 Learning Outcomes: 9.2 i) Overview female reproductive cycle: ovarian cycle and uterine/menstrual cycle Female Reproductive Cycle: Ovarian Menstrual/Uterine Cycle Cycle (in uterus) (in ovary) 1. Menstrual flow 1. Follicular phase phase 2. Proliferative 2. Luteal phase phase 3. Secretory phase 54 Learning Outcomes: 9.2 j) Explain ovarian cycle and its hormonal control Ovarian Cycle Cyclic events in the ovaries Once per cycle a follicle matures & an oocyte is released. Consists of 2 main phases i. follicular phase ii. luteal phase Between the 2 phases is ovulation 55 Learning Outcomes: 9.2 j) Explain ovarian cycle and its hormonal control Ovarian Cycle ~ Follicular phase The ovarian cycle begins when the hypothalamus releases GnRH, which stimulates the anterior pituitary to secrete small amount of FSH and LH. FSH stimulates follicle growth. The cells of the growing follicles (granulosa cells) start to secrete estrogen. Estrogen concentration slowly rises (days 0–14). 56 Learning Outcomes: 9.2 j) Explain ovarian cycle and its hormonal control Ovarian Cycle ~ Follicular phase Several follicles begin to grow with each cycle, but only one matures. A low concentration of estrogen inhibits secretion of pituitary hormones, keeping the concentration of FSH and LH relatively low. 57 Learning Outcomes: 9.2 j) Explain ovarian cycle and its hormonal control Ovarian Cycle ~ Follicular phase When estrogen secretion begins to rise steeply, it stimulates hypothalamus to secrete of GnRH. GnRH stimulates anterior pituitary gland to increase secretion FSH and LH making the levels of FSH and LH increase markedly. Large amount of LH secreted is called LH surge. 58 Learning Outcomes: 9.2 j) Explain ovarian cycle and its hormonal control Ovarian Cycle ~ Follicular phase The follicular phase ends at ovulation (day 14), about a day after the LH surge. The follicle and adjacent wall of the ovary rupture, releasing the secondary oocyte. 59 Learning Outcomes: 9.2 j) Explain ovarian cycle and its hormonal control Ovarian Cycle ~ Luteal phase The luteal phase (days 15–28) follows ovulation. LH stimulates the remaining follicular tissue to form the corpus luteum. Corpus luteum secretes progesterone and estrogen. 60 Learning Outcomes: 9.2 j) Explain ovarian cycle and its hormonal control Ovarian Cycle ~ Luteal phase High concentration of progesterone and estrogen exert negative feedback on the hypothalamus and anterior pituitary to reduce LH and FSH secretion. 61 Learning Outcomes: 9.2 j) Explain ovarian cycle and its hormonal control Ovarian Cycle ~ Luteal phase If pregnancy does not occur, the low concentration of FSH & LH cause the corpus luteum to disintegrate. This triggers a sharp decline in estrogen and progesterone concentrations. The anterior pituitary can then secrete enough FSH to initiate the next ovarian cycle. 62 Learning Outcomes: 9.2 k) Explain uterine/menstrual cycle and its hormonal control Uterine / Menstrual Cycle Changes in the uterus Is integrated with ovarian cycle 1st day of menstruation is day 1 for menstrual cycle. Averages 28 days. Consists of 3 phases: i. Menstrual flow phase ii. Proliferative phase iii. Secretory phase 63 Learning Outcomes: 9.2 k) Explain uterine/menstrual cycle and its hormonal control Uterine / Menstrual Cycle ~ Menstrual flow phase (Day 1-5) Begins when estrogen and progesterone level is low. This leads to constriction of small arteries in the endometrium that supplies oxygen. Cells of endometrium die and the endometrial tissue and blood begins to shed and discharged through menstruation. 64 Learning Outcomes: 9.2 k) Explain uterine/menstrual cycle and its hormonal control Uterine / Menstrual Cycle ~ Menstrual flow phase (Day 1-5) This stimulates hypothalamus to secrete GnRH. GnRH stimulates the anterior pituitary to secrete FSH and LH. 65 Learning Outcomes: 9.2 k) Explain uterine/menstrual cycle and its hormonal control Uterine / Menstrual Cycle ~ Menstrual flow phase (Day 1-5) FSH stimulates the growth and development of follicles in ovary. Developing follicle releases estrogen. 66 Learning Outcomes: 9.2 k) Explain uterine/menstrual cycle and its hormonal control Uterine / Menstrual Cycle ~ Proliferative phase (Day 6-14) Estrogen (secreted by the growing follicle in ovary) stimulates the repairing and thickens the endometrium. 67 Learning Outcomes: 9.2 k) Explain uterine/menstrual cycle and its hormonal control Uterine / Menstrual Cycle ~ Proliferative phase (Day 6-14) As follicle mature, it secretes more estrogen that stimulates the anterior pituitary gland to secrete more LH LH stimulates ovulation and the formation of corpus luteum 68 Learning Outcomes: 9.2 k) Explain uterine/menstrual cycle and its hormonal control Uterine / Menstrual Cycle ~ Secretory phase (Day 15-28) Corpus luteum secretes progesterone and estrogen which maintain the thickness of endometrium. Progesterone stimulates the growth of blood vessels and glands in endometrium. Arteries enlarge and endometrial glands grow to secrete fluid rich in glycogen prepare uterus for embryo implantation. 69 Learning Outcomes: 9.2 k) Explain uterine/menstrual cycle and its hormonal control Uterine / Menstrual Cycle ~ Secretory phase (Day 15-28) The high level of progesterone and estrogen inhibits the release of GnRH which inhibits FSH and LH secretion by negative feedback mechanism. If fertilization does not occur, the corpus luteum degenerates and both estrogen and progesterone level decreases. FSH and LH secretion is no longer inhibited thus allowing another cycle to begin. 70  LEARNING OUTCOMES 9.3 Fertilization And Foetal Development a) Explain stages that lead to fertilization (C3) i. Capacitation ii. Acrosomal reaction iii. Fusion of sperm head membrane and oocyte iv. Cortical reaction b) Define embryogenesis (C1) c) State developmental stages from zygote to the formation of morula, blastocyst and gastrula through cleavage. (C1) d) Define organogenesis. (C1) e) State the organ formed from each germ layers during organogenesis (C1) 71 Learning Outcomes : 9.3 (a) Explain stages that lead to fertilization. DEFINITION: The union of a haploid male and female gametes to produce a diploid zygote. Occurrence site: One third of the fallopian tube (oviduct) 72 Learning Outcomes : 9.3 (a) Explain stages that lead to fertilization Stages of fertilization: 1) Capacitation 2) Acrosomal reaction 3) Fusion of sperm head membrane and oocyte 4) Cortical reaction 73 Learning Outcomes : 9.3 (a) Explain stages that lead to fertilization STAGE 1: CAPACITATION The functional maturation of sperm through the female secretion in reproductive tract. The sperm motility is increased. Certain molecules on the sperm is altered: ⮚ The removal of cholesterol, glycoprotein & protein of the acrosomal cap → for acrosomal reaction Enable spermatozoa to penetrate membrane surrounding the egg / corona radiata 74 Learning Outcomes : 9.3 (a) Explain stages that lead to fertilization STAGE 1: CAPACITATION When sperm are exposed to the female tract environment, these seminal plasma coatings, along with some of the surface molecules, are removed Exposing portions of the molecules that can bind to the zona pellucida of the oocyte. 75 Learning Outcomes : 9.3 (a) Explain stages that lead to fertilization STAGE 1: CAPACITATION The capacitated sperm move through layers of follicle cells and reaches zona pellucida. This triggering exocytosis of the sperm’s acrosome 76 Learning Outcomes : 9.3 (a) Explain stages that lead to fertilization STAGE 2: ACROSOMAL REACTION The binding between the complementary membrane protein of sperm head with specific receptor on the zona pellucida leads to acrosomal reaction. Acrosome membrane disperse/rupture. The hydrolytic enzymes is released from acrosome into zona pellucida via exocytosis. Hydrolytic enzymes : ⮚ Hyaluronidase ⮚ Protease @ acrosin 77 Learning Outcomes : 9.3 (a) Explain stages that lead to fertilization STAGE 2: ACROSOMAL REACTION The zona pellucida is hydrolysed/ digested by the enzymes To enable the penetration of sperm. 78 Learning Outcomes : 9.3 (a) Explain stages that lead to fertilization STAGE 2: ACROSOMAL REACTION 79 Learning Outcomes : 9.3 (a) Explain stages that lead to fertilization STAGE 3: FUSION OF SPERM HEAD MEMBRANE AND OOCYTE The sperm’s head membrane fuse with secondary oocyte’s plasma membrane Fusion of sperm head triggers cortical reaction. 80 Learning Outcomes : 9.3 (a) Explain stages that lead to fertilization STAGE 4: CORTICAL REACTION During cortical reaction , cortical granule release enzyme by exocytosis The enzyme will destroy sperm receptors on zona pellucida and harden zona pellucida These enzymes catalyze change in zona pellucida which then functions as the slow block to polyspermy 81 Learning Outcomes : 9.3 (a) Explain stages that lead to fertilization STAGE 4: CORTICAL REACTION Sperm enters secondary oocyte and stimulate secondary oocyte to complete meiosis II and ovum is formed. Lastly, pronuclei of sperm and ovum fuse to form diploid zygote (2n) 82 Learning Outcomes : 9.3 (b) Define embryogenesis. EMBRYOGENESIS DEFINITION: A process by which embryo is formed and developed. Process by which the number of cells in the developing embryo is multiplied through cell division. 83 Learning Outcomes : 9.3 (c) State developmental stages from zygote to the formation of morula, blastocyst and gastrula through cleavage. STAGES IN EMBRYOGENESIS STAGE FORM OF EMBRYO CLEAVAGE Morula Blastocyst GASTRULATION Gastrula ORGANOGENESIS Begins with neurula 84 Learning Outcomes : 9.3 (c) State developmental stages from zygote to the formation of morula, blastocyst and gastrula through cleavage. CLEAVAGE After fertilization, the fertilized egg starts traveling down the fallopian tube toward the uterus. Zygote undergoes cleavage (rapid mitotic divisions and cell differentiation) at oviduct/ fallopian tube Development from zygote into blastocyst: ⮚ Increase the cell number. ⮚ The size of cell does not increase → No growth period( G1 & G2) Smaller cells produced by cleavage are called as blastomere. 85 Learning Outcomes : 9.3 (c) State developmental stages from zygote to the formation of morula, blastocyst and gastrula through cleavage. CLEAVAGE Initially zygote divide forming two-celled embryo. Repeated division forms four-celled and continue dividing forming 32 cells called morula. Morula: ⮚ A solid sphere of cells (still surrounded by zona pellucida). ⮚ The size of the original zygote. ⮚ Completes at the end of the third day. ⮚ Floats in the uterus by several days and nourished by endometrial secretions. 86 Learning Outcomes : 9.3 (c) State developmental stages from zygote to the formation of morula, blastocyst and gastrula through cleavage. 87 Learning Outcomes : 9.3 (c) State developmental stages from zygote to the formation of morula, blastocyst and gastrula through cleavage. CLEAVAGE Cell continue dividing forming 64 to several hundreds of blastomeres forming blastocyst. ⮚ A sphere of cells with fluid-filled space (blastocoel). ⮚ Zona pellucida sheds. ⮚ Implants to endometrium; occur 1 week after fertilization. 88 Learning Outcomes : 9.3 (c) State developmental stages from zygote to the formation of morula, blastocyst and gastrula through cleavage. 89 Learning Outcomes : 9.3 (c) State developmental stages from zygote to the formation of morula, blastocyst and gastrula through cleavage. 90 Learning Outcomes : 9.3 (c) State developmental stages from zygote to the formation of morula, blastocyst and gastrula through cleavage. CLEAVAGE After blastocyst reaching uterus, blastomeres differentiate into: ⮚ Inner cell mass (cluster of cell at one end of blastocyst) - from which the embryo will form ⮚ Trophoblast (Outer epithelium of blastocyst) 91 Learning Outcomes : 9.3 (c) State developmental stages from zygote to the formation of morula, blastocyst and gastrula through cleavage. 92 Learning Outcomes : 9.3 (c) State developmental stages from zygote to the formation of morula, blastocyst and gastrula through cleavage. IMPLANTATION 93 Learning Outcomes : 9.3 (c) State developmental stages from zygote to the formation of morula, blastocyst and gastrula through cleavage. GASTRULATION As implantation is completed, gastrulation begins. Gastrulation is the formation of three germ layers from blastocyst into gastrula. The inner cell mass differentiated into 3 embryonic germ layers. i. Ectoderm ii. Mesoderm iii. Endoderm 94 Learning Outcomes : 9.3 (c) State developmental stages from zygote to the formation of morula, blastocyst and gastrula through cleavage. GASTRULATION 95 Learning Outcomes : 9.3 (c) State developmental stages from zygote to the formation of morula, blastocyst and gastrula through cleavage. GASTRULATION Gastrula surrounded by 4 extraembryonic membrane: i. Chorion ii. Amnion iii. Allantois iv. Yolk sac 96 Learning Outcomes : 9.3 (d) Define organogenesis. ORGANOGENESIS Process of organ formation. Arise from three germ layers. Morphogenesis and cell differentiation continue to refine the organ. 97 Learning Outcomes : 9.3 (d) Define organogenesis. ORGANOGENESIS Initial stage of organogenesis is neurulation. Process of NEURAL TUBE FORMATION. ⮚ Occurs along the midline of embryo. ⮚ Neural tube will develop into brain and spinal cord. NOTOCHORD (early backbone) ⮚ Is flexible rod formed from mesoderm layer ⮚ Develop into vertebral column disc 98 Learning Outcomes : 9.3 (d) Define organogenesis. ORGANOGENESIS 99  LEARNING OUTCOMES 9.4 Roles of Hormones During Pregnancy and Parturition a) Explain the roles of hormones during pregnancy (C3) i. Progesterone; ii. Estrogen; and iii. Human chorionic gonadotropin (hCG). a) Explain the roles of hormones during parturition / birth process (C3) i. Progesterone iii. Oxytocin ii. Estrogen; iv. Prostaglandin. 100 Learning Outcome: 9.4 a) Explain the roles of hormones during pregnancy ROLES OF HORMONE DURING PREGNANCY trophoblast cells hCG corpus luteum estrogen endometrium progesterone developed placenta 101 Learning Outcome: 9.4 a) Explain the roles of hormones during pregnancy ROLES OF HORMONE DURING PREGNANCY 102 Learning Outcome: 9.4 a) Explain the roles of hormones during pregnancy ROLES OF HORMONE DURING PREGNANCY FIRST TRIMESTER (1-3 month) After implantation, the trophoblast cells of blastocyst starts to secrete hCG (human chorionic gonadotropin). ⮚ hCG maintains the corpus luteum / prevents degeneration of the corpus luteum. ⮚ In the absence of hCG, corpus luteum would degenerate, progesterone and estrogen level would drop, resulting in menstruation & loss of embryo. 103 Learning Outcome: 9.4 a) Explain the roles of hormones during pregnancy ROLES OF HORMONE DURING PREGNANCY FIRST TRIMESTER (1-3 month) hCG stimulates the corpus luteum to grow and continue secretion of estrogen and progesterone. ⮚ Estrogen stimulate development of uterus. ⮚ Progesterone maintain the thickness of endometrium for embryonic development. Progesterone > Estrogen 104 Learning Outcome: 9.4 a) Explain the roles of hormones during pregnancy ROLES OF HORMONE DURING PREGNANCY FIRST TRIMESTER (1-3 month) Progesterone > Estrogen High level of progesterone prevent miscarriage / maintain pregnancy. hCG level increases dramatically during the first trimester. End of first trimester, placenta takes over the roles of corpus luteum. ⮚ Placenta will secrete estrogen and progesterone. 105 Learning Outcome: 9.4 a) Explain the roles of hormones during pregnancy ROLES OF HORMONE DURING PREGNANCY SECOND TRIMESTER (4-6 month) By the middle of pregnancy, ⮚ hormone level stabilizes as hCG secretion decline. ⮚ corpus luteum degenerate. ⮚ placenta completely take over the production of estrogen and progesterone. Progesterone > Estrogen Higher estrogen will cause miscarriage / premature birth because estrogen induce uterus contraction. 106 Learning Outcome: 9.4 a) Explain the roles of hormones during pregnancy ROLES OF HORMONE DURING PREGNANCY SECOND TRIMESTER (4-6 month) High level of progesterone: maintains the pregnancy. inhibits secretion of prolactin and oxytocin (prevent lactation until after birth). bring rapid changes in the mother: i. mucus in the cervix forms a plug that protects against infection. ii. maternal part of the placenta grows. iii. mother’s breast and uterus get larger. iv. prevent ovulation and menstrual cycle. 107 Learning Outcome: 9.4 a) Explain the roles of hormones during pregnancy ROLES OF HORMONE DURING PREGNANCY THIRD TRIMESTER (7-9 month) Final week of pregnancy, estrogen reaches its highest level. ⮚ Stimulate formation of oxytocin receptors on uterus. Progesterone level decrease. ⮚ Stimulate the beginning of contraction that will lead to birth. 108 Learning Outcome: 9.4 b) Explain the roles of hormones during parturition / birth process ROLES OF HORMONE DURING PARTURITION 109 Learning Outcome: 9.4 b) Explain the roles of hormones during parturition / birth process ROLES OF HORMONE DURING PARTURITION Oxytocin released by the fetus and mother's posterior pituitary gland ⮚ stimulates uterus contraction. Oxytocin also stimulates placenta to secrete prostaglandins ⮚ stimulate more contraction of uterus. 110 Learning Outcome: 9.4 b) Explain the roles of hormones during parturition / birth process ROLES OF HORMONE DURING PARTURITION Both oxytocin and prostaglandins induce and regulate contractions of the uterus. Uterine contractions stimulate secretion of more oxytocin & prostaglandins ⮚ which in turn stimulates further contractions. 111 Learning Outcome: 9.4 b) Explain the roles of hormones during parturition / birth process ROLES OF HORMONE DURING PARTURITION Action of oxytocin and prostaglandins forms a positive-feedback loop. Positive feedback loop: Hormones cause a condition to intensify As the condition intensifies, hormone production increases 112  LEARNING OUTCOMES 9.5 Growth Patterns in Human and Plants. a) Definition of growth. (C1) i. Explain the human growth curve; (C3) ii. Explain allometric growth (human organs); (C3) iii. Explain limited growth (annual plants) and unlimited growth (perennial plants). (C3) 113 Learning Outcomes : 9.5 (a) Definition of growth. GROWTH DEFINITION: Any permanent and irreversible increase in quantitative (measureable) parameters over a specific time. Parameters: volume, width, length, height, cell number, dry mass, surface areas and biomass. E.g: Length over specific time 114 Learning Outcomes : 9.5 (b) Explain the human growth curve. HUMAN GROWTH CURVE Growth in humans refers to an increase in size. 115 Learning Outcomes : 9.5 (b) Explain the human growth curve. Growth in human refers to an increase in mass / height Shows a modified sigmoid curve Human has two main rapid growth: i. Infant phase ii. Adolescent phase Between these 2 phases, there is a period of a relatively slow growth. Adulthood is when growth is halt. 116 Learning Outcomes : 9.5 (b) Explain the human growth curve. 1. Infant phase: Rapid growth rate Irrespective in both male or female babies. 2. Childhood phase: Slower growth rate Beginning at the age of four, the rate is slightly higher in boys than in girls 117 Learning Outcomes : 9.5 (b) Explain the human growth curve. 3. Adolescent phase: Rapid growth rate In the earlier part of this growth phase, females demonstrate a more rapid growth rate i.e. two years earlier than begins in males 118 Learning Outcomes : 9.5 (b) Explain the human growth curve. 3. Adolescent phase: At the later part of this growth phase, the male growth rate becomes higher than the female growth rate. ⮚ This difference results in the females attaining puberty at an earlier age compared to males. ⮚ Females attain puberty around the age of 12, while males attain puberty when they are about 14 years old. 119 Learning Outcomes : 9.5 (b) Explain the human growth curve. 4. Adult phase: Growth rate is zero Most individual have attained maturity Males achieve this phase at about 18 years old while females around 16. 5. Ageing phase: Growth rate is negative Body proportion start to decrease starting from the age of 30. 120 Learning Outcomes : 9.5 (c) Explain allometric growth (human organs). ALLOMETRIC GROWTH Growth of an organ at different rate compared to the rest of the body. The organism increases in size is accompanied by the changes in shape. The relative size of organs are different from the final size. In human organs. 121 Learning Outcomes : 9.5 (c) Explain allometric growth (human organs). ALLOMETRIC GROWTH 122 Learning Outcomes : 9.5 (c) Explain allometric growth (human organs). BODY SYSTEM DESCRIPTION 1. Head ▪ Grows rapidly for 1st five years after birth and thereafter it does not grow much. 123 Learning Outcomes : 9.5 (c) Explain allometric growth (human organs). BODY SYSTEM DESCRIPTION 2. Lymphoid tissue ▪ Grows rapidly from birth to early adolescence; Higher risk of infection in early life because immunity has not acquired yet. ▪ Decreases to half of maximum size by adult stage. 124 Learning Outcomes : 9.5 (c) Explain allometric growth (human organs). BODY SYSTEM DESCRIPTION 3. Reproductive ▪ Grow very slowly in early life but organs rapidly at puberty (during adolescence). 125 Learning Outcomes : 9.5 (c) Explain allometric growth (human organs). In embryos, the brain and the head will both start grow and develop in the early phase of life. The head of an infant is much larger relative to the rest of body as compared to an adult. 126 Learning Outcomes : 9.5 (d) Explain limited growth (annual plants) and unlimited growth (perennial plants). LIMITED GROWTH CURVE Shows sigmoid growth curve. An organism grows to a maximum size and then stop growing (relatively short life span). Growth is complete when the organism achieves its maximum size. Negative growth rate or senescence is showed finally. In annual plants e.g. maize plants & Pisum sativum (pea plants). 127 Learning Outcomes : 9.5 (d) Explain limited growth (annual plants) and unlimited growth (perennial plants). LIMITED GROWTH CURVE STAGES CHANGES OF DRY MASS 1. Initial stage ▪ Slight decrease in dry mass; Food stored of in seed used for aerobic respiration. germination 128 Learning Outcomes : 9.5 (d) Explain limited growth (annual plants) and unlimited growth (perennial plants). LIMITED GROWTH CURVE STAGES CHANGES OF DRY MASS 2. Growth and ▪ Large increase in dry mass; first leaves emerges development and starts to photosynthesize. of plants. ▪ Growth rate is very rapid; rate of photosynthesis > rate of respiration. ▪ Growth rate is constant at later stage; Plant matures and reproduces. 129 Learning Outcomes : 9.5 (d) Explain limited growth (annual plants) and unlimited growth (perennial plants). LIMITED GROWTH CURVE STAGES CHANGES OF DRY MASS 3. Before the ▪ Decrease in dry mass; Due to senescence, fall of death of plant leaves and dispersal of seeds. ▪ Senescence: Rate of cell death > rate of cell division. 130 Learning Outcomes : 9.5 (d) Explain limited growth (annual plants) and unlimited growth (perennial plants). UNLIMITED GROWTH CURVE Comprises a series of smaller sigmoid curves. Each curve = Growth in ONE YEAR. Non-stop growth over a relatively long life span. 131 Learning Outcomes : 9.5 (d) Explain limited growth (annual plants) and unlimited growth (perennial plants). UNLIMITED GROWTH CURVE Organisms grow continuously throughout life until natural disaster / catastrophe or diseases occurs. In perennial plants: Plants grow and reproduce for many years. e.g. woody plants, Hibiscus sp. 132 Learning Outcomes : 9.5 (d) Explain limited growth (annual plants) and unlimited growth (perennial plants). UNLIMITED GROWTH CURVE 133 Learning Outcomes : 9.5 (d) Explain limited growth (annual plants) and unlimited growth (perennial plants). UNLIMITED GROWTH CURVE Corresponding to 4 seasons: (i) Spring ⮚ The temperature and light intensity are low, there is very little photosynthesis ⮚ Results in a small increase in the height of the plants (ii) Summer ⮚ The temperature and light intensity are high, the rate of photosynthesis is high ⮚ Results in a large increase in the height of the plants 134 Learning Outcomes : 9.5 (d) Explain limited growth (annual plants) and unlimited growth (perennial plants). UNLIMITED GROWTH CURVE (iii) Autumn ⮚ The temperature and light intensity are lower than those in summer ⮚ Less photosynthesis and therefore the small increase in the height of plants (iv) Winter ⮚ There is no growth as there is no or very little photosynthesis 135  REFERENCES Campbell, N.A., Urry, L.A., Cain, M.L., Wasserman, S.A., Minorsky, P.V. & Orr, R.B. (2021). Biology: A global approach. (12th ed). Pearson Education Limited. Solomon, E.P., Berg, L.R. & Martin, D.W. (2018). Biology. (11th ed.). Cencage Learning, Inc. Solomon E.P & Berg, L.R.(2005). Biology. (7th ed.). Thomson Learning, Inc. Marieb, E.N. & Hoehn, K. (2023). Human anatomy & Physiology, 12th Global edition, Pearson Education Limited. 136  REFERENCES (FIGURE) Figure 1 – https://waynesword.net/lmexer8.htm Figure 2 – Adapted from Campbell 12th ed., page 645 Figure 3a – https://biology4isc.weebly.com/sexual-reproduction-in-flowering-plants.html Figure 3b – Adapted from page 894 Clark, M. A., Douglas, M., & Choi, J. (2018). Biology 2e. Houston, Texas: OpenStax. Retrieved from https://openstax.org/books/biology-2e/pages/1-introduction Figure 4 – Page 895 Clark, M. A., Douglas, M., & Choi, J. (2018). Biology 2e. Houston, Texas: OpenStax. Retrieved from https://openstax.org/books/biology-2e/pages/1-introduction Figure 5 – Campbell 12th ed., page 827 Figure 6 – Campbell 12th ed., page 827 Figure 7 – Adapted from https://digital.library.wisc.edu/1711.dl/6RG35XQ652VVG8U Figure 8 – https://www.slideshare.net/slideshow/biology-form-5-chapter-4-45-sexual-reproduction-in- flowering-plants/38295100 Figure 9a & 9b – Adapted from Campbell 12th ed., page 828 Figure 10 – https://www.slideshare.net/slideshow/biology-form-5-chapter-4-45-sexual-reproduction-in- flowering-plants/38295100 Figure 11 – Raven 12th ed., page 883 Figure 12 – Campbell 12th ed., page 828 Figure 13 – https://people.wou.edu/~guralnl/osumeiosis.PDF Figure 14 – Adapted from Campbell 12th ed., page 1025 Figure 15 – Adapted from Campbell 12th ed., page 1028 Figure 15 – Adapted from Campbell 12th ed., page 1028 Figure 17 – Campbell 12th ed., page 1031 Figure 18 – Campbell 12th ed., page 1028 Figure 19 – Campbell 12th ed., page 1027 & 1029 Figure 20 – Adapted from https://collegedunia.com/exams/ovum-biology-articleid-4794 and Campbell 12th ed., page 1029 Figure 21 – Campbell 12th ed., page 1029 137  REFERENCES (FIGURE) Figure 22 – Campbell 12th ed., page 1032 Figure 23a – Essentials of Human Anatomy & Physiology Global edition 12th ed. page 585 and Mader 12th ed., page 793 Figure 23b –https://commons.wikimedia.org/wiki/File:Fertilization.jpg Figure 24 – Adapted from Mader 12th ed., page 794 Figure 25 – Adapted from https://www.researchgate.net/figure/Conceptual-version-of-mammalian- capacitation_fig1_325093545 Figure 26 – Adapted from Mader 12th ed., page 794 Figure 27 – Adapted from Mader 12th ed., page 794 Figure 28 – Adapted from Copyright © 2002 Pearson Education, Inc., publishing as Benjamin Cummings Figure 29 – Adapted from Mader 12th ed., page 794 Figure 30 – Adapted from Campbell 12th ed., page 1045 Figure 31 – Human anatomy & Physiology, 12th Global ed., page 1131 Figure 32 – https://nerddoc.wordpress.com/blastulation-embryology/ Figure 33 – https://www.mayoclinic.org/healthy-lifestyle/pregnancy-week-by-week/multimedia/fertilization- and-implantation/img-20008656 Figure 34 – Essentials of Human Anatomy & Physiology Global edition 12th ed. page 586 Figure 35 – Adapted from Solomon 11th ed., page 1108 , Campbell 12th ed., page 1048 and https://www.nationalgeographic.com/science/article/the-morula-solution Figure 36 – Adapted from Raven 12th ed., page 1158 Figure 37 – Human anatomy & Physiology, 12th Global ed., page 1132 Figure 38 – Campbell 12th ed., page 1035 Figure 39 – Solomon 11th ed., page 1117 Figure 40 – Adapted from Mader 12th ed., page 804 Figure 41 – Adapted from https://www.invitra.com/en/embryo-implantation/ Figure 42 – Campbell 12th ed., page 1053 138  REFERENCES (FIGURE) Figure 43 – Adapted from Campbell 12th ed., page 1053 Figure 44 – https://www.invitra.com/en/gastrulation/organogenesis Figure 45 – Essentials of Human Anatomy & Physiology Global edition 12th ed. page 586 Figure 46 – https://www.brainkart.com/article/Prenatal-Development_22001/ Figure 47 – Adapted from https://mstranslate.com.au/female-sex-hormones-multiple- sclerosis/secretion_levels/ Figure 48 – Campbell 12th ed., page 1036 Figure 49 – https://newatlas.com/health-wellbeing/metabolic-aging-energy-expenditure-lifespan-study/ Figure 50 – https://www.clipartmax.com/max/m2H7d3H7K9m2G6i8/ Figure 51 – https://www.slideshare.net/slideshow/biology-form-5-chapter-4-46-growth-in-multicellular- organisms/63597714#32 Figure 52 – https://radiologykey.com/late-effects-of-cancer-treatment/ (From Tanner JM. Growth at Adolescence. Oxford: Blackwell Scientific, 1962) Figure 53 – https://entokey.com/characteristics-of-normal-and-abnormal-postnatal-craniofacial-growth- and-development/ Figure 54 – https://www.uaex.uada.edu/counties/miller/news/fcs/fruits-veggies/green-peas-a-vitamin- powerhouse.aspx Figure 55 – Adapted from https://wazaelimu.com/topic-2-growth-and-development-biology-form-6/ Figure 56 – Published by Oscar Garret, https://slideplayer.com/slide/6077305/18/images/28/Growth+patterns+Unlimited+Growth+Curves.+19.+Th e+growth+curve+for+unlimited+growth+comprises+a+series+of+small+sigmoid+curves..jpg Figure 57 – Adapted from Zahavah Olsen https://image.slideserve.com/792356/slide31-l.jpg 139