DP bio final

Advantage of sexual reproduction

→ Produces genetic variation, increasing adaptability to changing environments.

Spermatogenisis steps

Oogenesis steps

Advantage of asexual reproduction

→ Rapid production of genetically identical offspring well adapted to stable environments.

Meiosis

A type of cell division that reduces the chromosome number by half, resulting in four genetically diverse gametes. This process is essential for sexual reproduction.

Haploid (n)

→ Having one set of chromosomes.

Diploid (2n)

→ Having two sets of chromosomes.

Gamete

→ A haploid sex cell (sperm or egg) capable of fusion at fertilization.

Zygote

→ A diploid cell formed by fusion of two haploid gametes.

Testis

→ Produces sperm and testosterone.

Epididymis

→ Stores and matures sperm before ejaculation.

Vas deferens

→ Transports sperm from epididymis to urethra.

Seminal vesicle

→ Produces fructose-rich fluid to supply energy for sperm.

Cowper’s gland

→ Secretes alkaline mucus to lubricate and neutralize the urethra.

Prostate gland

→ Produces alkaline fluid that improves sperm survival.

Cervix

→ Muscular opening between uterus and vagina.

Oestradiol

→ Repairs and thickens the endometrium and stimulates LH release.

Progesterone

→ Maintains the endometrium for pregnancy.

FSH (Follicle-stimulating hormone)

→ Stimulates follicle development and spermatogenesis.

LH (Luteinizing hormone)

→ Triggers ovulation and stimulates testosterone production.

Ovulation

→ Release of a secondary oocyte from the ovary.

Corpus luteum

→ Secretes progesterone after ovulation.

Superovulation

→ Hormonal stimulation causing multiple eggs to mature simultaneously.

Acrosome

→ Structure containing enzymes that digest the zona pellucida.

Acrosome reaction

→ Release of enzymes allowing sperm penetration of the egg.

Cortical granules

→ Vesicles that release enzymes after fertilization.

Cortical reaction

→ Hardening of the zona pellucida to prevent polyspermy.

1. MENSTRUAL CYCLE (OVARIAN + UTERINE)

menstruation, repair, ovulation, luteal, shed

→ FOLP (FSH, Oestradiol, LH, Progesterone)

→ Low → rise → surge → high → fall

→ menstruation: all low

→ repair: FSH + oestradiol rise

→ ovulation: LH surge

→ luteal: progesterone high

→ shed: progesterone falls

Pregnancy maintenance

implantation, early pregnancy, late pregnancy
→ HCP (hCG, Corpus luteum, Placenta)
→ Maintain → transfer → maintain
→ early: hCG maintains corpus luteum
→ corpus luteum: progesterone high
→ later: placenta secretes progesterone + oestradiol

Childbirth

uterine stretch, contractions, birth
→ SOPP (Stretch, Oxytocin, Positive feedback, Push)
→ Low P → high O → more O
→ progesterone falls
→ oxytocin released
→ contractions strengthen via positive feedback
→ cervix dilates → birth

Puberty

childhood inhibition, hormone release, maturity
→ GnFLUSH (GnRH → FSH/LH → sex hormones)
→ Low → rise → develop
→ GnRH increases
→ FSH + LH increase
→ sex hormones increase
→ secondary sexual characteristics develop

Oxytocin

→ Hormone that stimulates uterine contractions.

positive feedback loop during child birth contractions increase oxytocin relase

Set Point

Ideal value for a variable (e.g. 37°C body temp)

Insulin

Function: Lowers blood glucose
Source: Beta cells
Action: Glucose → Glycogen

Glucagon

Function: Raises blood glucose
Source: Alpha cells
Action: Glycogen → Glucose

Islets of Langerhans

Definition: Hormone-producing regions of pancreas
Mnemonic: “Islets = hormone islands”

Glycogen

Definition: Storage form of glucose
Location: Liver & muscles
Mnemonic: “GLYCO-GEN = glucose generator”

Hypothalamus

Function: Temperature control center

Thyroxine

Effect: Increases metabolic rate

Kidney

Function: Excretion + osmoregulation

Nephron

Definition: Functional unit of kidney

Kidney structure

glomerulus, carries out ultrafiltration of blood; Bowman’s capsule collects the filtrate; proximal convoluted tubule, reabsorbs glucose, amino acids, ions, and most water by active transport and diffusion; descending limb of the loop of Henle, is permeable to water allowing water to leave by osmosis and concentrate the filtrate; ascending limb of the loop of Henle, is impermeable to water and pumps sodium and chloride ions out to create a salt gradient; distal convoluted tubule, regulates ion balance and pH and responds to aldosterone; collecting duct, reabsorbs water under the control of ADH and determines urine concentration; renal pelvis collects urine; ureter transports urine to the bladder.

Signal Transduction

Definition: Series of reactions triggered after ligand binds

Quorum Sensing

Definition: Bacterial communication using chemical signals to coordinate behavior

Autoinducers

Definition: Signalling molecules released by bacteria