Reproductive Physiology Flashcards
(46 cards)
Why is sexual reproduction favored over simple cloning in most animals?
It introduces genetic variability through recombination, helping species adapt and avoid perpetuating “bad” traits
What is parthenogenesis?
A form of asexual reproduction in which females produce offspring (clones) without fertilization (e.g., aphids in spring/summer).
How do some aphids switch to sexual reproduction in autumn?
Environmental cues (shorter days, cooler temps) trigger them to make males and eggs, ensuring genetic diversity and overwintering.
What are the two main purposes of meiosis?
- Reduce chromosome number from 2n → n
- Shuffle genes (crossing‑over) to create diverse gametes
During which meiotic phase does crossing‑over occur?
Prophase I—homologous chromosomes pair and exchange segments, generating new allele combinations.
How many gametes result from one meiotic cycle?
Four genetically distinct haploid (n) cells.
Define gonads.
Organs that produce gametes—testes in males, ovaries in females.
In the testis “balloon” model, what do the “spaghetti” represent?
The seminiferous tubules, where sperm develop; held in the “balloon” (tunica), bathed in interstitial fluid.
What cell types fill the interstitial space between seminiferous tubules?
Leydig cells (produce testosterone), blood vessels, nerves, and connective tissue.
Name the two key requirements for successful gamete production & fertilization.
- Viable gametes (made & stored)
- Delivery system for sperm → egg (e.g. ducts, copulation)
What triggers seasonal breeding in some mammals (e.g., deer)?
Photoperiod (day length) and hormonal signals that switch gonadal activity on/off.
Give one example of regeneration in animals and its research significance.
Planarian flatworms regrow entire bodies after fragmentation—model for understanding tissue regeneration.
Why study diverse species (insects, slugs, plants) in reproductive physiology?
Each offers unique mechanisms (e.g. parthenogenesis, regeneration, seasonal breeding) that inform broader biological principles.
What is the end goal of all reproductive strategies?
Successful offspring production and survival to carry on the species.
Why can’t somatic (body) cells undergo meiosis?
Only germ cells in the gonads have the specialized machinery to perform reduction division and generate gametes.
What is the function of the blood-testis barrier?
Prevents immune system attack on developing sperm by isolating them from blood.
What are the two main cell types in seminiferous tubules?
Sertoli cells (support, nourish, regulate sperm development)
👉 Spermatogenic cells (develop into sperm)
What is the role of Sertoli cells?
Support spermatogenesis, form the blood-testis barrier, and facilitate meiosis and sperm release.
What process forms sperm from stem cells?
Spermatogenesis, which includes mitosis, meiosis I & II, and differentiation.
Where does spermatogenesis occur?
inside seminiferous tubules in the testes.
What are the three parts of a sperm?
Head (DNA + acrosome), Neck (mitochondria), Tail (flagellum for motility)
Why are many sperm needed for fertilisation?
To break barriers around the egg and ensure one successful fertilisation.
What is sperm maturation and where does it occur?
Maturation = sperm becomes motile and fertilising
👉 Happens in the epididymis
What is the function of the epididymis?
Stores and matures sperm; adds surface proteins (antigens).
