BIOLOGY BLOCK 5

What is fission in reproduction?

One organism splits into two genetically identical offspring. Example: Amoeba.

What is budding in reproduction?

New organism grows from parent and detaches. Example: Hydra.

What is fragmentation and regeneration in reproduction?

Parent breaks into pieces that regenerate. Examples: Starfish, Planaria.

What is parthenogenesis?

Egg develops without fertilization. Examples: Honeybees, ants, some lizards.

What is the function of the ovary in female reproductive anatomy?

Produces eggs (ova).

What is the function of the oviduct (Fallopian Tube)?

Site of fertilization. Egg travels to uterus here.

What are fimbriae?

Fingerlike projections that sweep egg into oviduct.

What is the function of the uterus?

Site of embryo development.

What is the endometrium?

Inner uterine lining where implantation occurs.

What is the function of the vagina?

Birth canal.

What are testes responsible for?

Produce sperm and testosterone.

What do seminiferous tubules do?

Site of sperm production.

What are Leydig cells?

Produce testosterone when stimulated by LH.

What do Sertoli cells do?

Nourish developing sperm. Stimulated by FSH. Produce inhibin.

What is the role of the epididymis?

Sperm maturation and storage.

What is the function of the vas deferens?

Transports sperm.

What do seminal vesicles provide for sperm?

Fructose for sperm energy.

What does the prostate gland produce?

Alkaline fluid.

What does Cowper's gland produce?

Produces mucus.

What is contained in the sperm head?

Contains nucleus and acrosome.

What is the acrosome in sperm?

Contains enzymes used to penetrate egg.

What does the OAT mnemonic (SEVEn UP) represent?

Path of Sperm: Seminiferous Tubules → Epididymis → Vas Deferens → Ejaculatory Duct → Urethra → Penis.

What are oogonia?

Diploid precursor cells in oogenesis.

What is a primary oocyte?

Arrested in Prophase I before birth.

What is a secondary oocyte?

Arrested in Metaphase II. Released during ovulation.

What triggers ovulation?

LH surge.

What does fertilization cause in terms of meiosis?

Completion of Meiosis II.

What are spermatogonia?

Stem cells in testes.

What is a primary spermatocyte?

Undergoes Meiosis I.

What is a secondary spermatocyte?

Undergoes Meiosis II.

What are spermatids?

Immature sperm.

What are spermatozoa?

Mature sperm.

What is capacitation?

Final sperm maturation inside female reproductive tract.

What does GnRH do?

Released by hypothalamus.

What is the function of FSH?

Stimulates follicle development and Sertoli cells.

What does LH do?

Triggers ovulation. Stimulates Leydig cells.

What does estrogen do in the menstrual cycle?

Thickens endometrium.

What is the role of progesterone?

Maintains endometrium.

What does hCG do?

Maintains corpus luteum during pregnancy. Detected by pregnancy tests.

What does inhibin do?

Inhibits FSH release.

What happens during the follicular phase of the menstrual cycle?

Follicle development and estrogen rises.

What triggers ovulation?

Occurs due to LH surge.

What happens during the luteal phase?

Corpus luteum produces progesterone and estrogen.

What is the corpus luteum?

Produces estrogen and progesterone.

What is the corpus albicans?

Degenerated corpus luteum.

Where does fertilization occur?

In the Fallopian tube.

What is the zona pellucida?

Glycoprotein layer around the egg.

What is ZP3?

Sperm receptor on zona pellucida.

What is the acrosome reaction?

Releases enzymes to penetrate egg.

What is the fast block to polyspermy?

Membrane depolarization.

What is the slow block to polyspermy?

Cortical granule release.

What is a zygote?

Diploid fertilized egg.

What is the embryonic development sequence?

Zygote → Cleavage → Morula → Blastula/Blastocyst → Gastrula → Neurula → Organogenesis.

What is cleavage?

Rapid mitosis without growth.

What is a blastomere?

Cell produced during cleavage.

What is a morula?

Solid ball of cells.

What does totipotent mean?

Can become entire organism. Morula cells are totipotent.

What is a blastula / blastocyst?

Fluid-filled cavity. Blastula is a hollow ball of cells, and blastocyst is a human blastula containing inner cell mass.

What is the inner cell mass?

Forms the embryo.

What does the trophoblast form?

Forms the placenta.

What does pluripotent mean?

Can form all body tissues but cannot form a whole organism.

What is gastrulation?

Formation of three germ layers.

What is a blastopore?

Opening formed during gastrulation.

What is an archenteron?

Primitive gut.

What is the fate of the blastopore in protostomes?

Blastopore → Mouth.

What is the fate of the blastopore in deuterostomes?

Blastopore → Anus. Humans are deuterostomes.

What is the ectoderm responsible for?

Forms the brain, spinal cord, nervous system, epidermis, hair, lens, retina, and adrenal medulla.

What does the mesoderm form?

Muscle, bone, blood, heart, kidneys, gonads, dermis, and connective tissue.

What does the endoderm form?

Lining of the digestive and respiratory tracts, liver, pancreas, thyroid, and parathyroid.

What is the notochord?

Mesoderm structure that induces neural tube formation.

What does the neural tube form?

Central nervous system (CNS).

What do neural crest cells form?

Teeth, facial bones, pigment cells, and peripheral nerves.

What does the chorion form?

Forms the placenta.

What does the amnion provide?

Fluid-filled protective sac.

What does the allantois form?

Forms umbilical cord and transports waste.

What does the yolk sac do?

Forms early blood cells in mammals.

What are homeotic (Hox) genes?

Control body pattern development.

What is apoptosis?

Programmed cell death that removes webbing between fingers/toes.

What is embryonic induction?

One group of cells influences another group's development.

What are cytoplasmic determinants?

Unevenly distributed molecules that influence cell fate.

What are stem cells?

Totipotent (entire organism possible, e.g., morula), pluripotent (any body cell, e.g., blastocyst), multipotent (limited tissue types), unipotent (one cell type).