D3 Continuity and Change : Organisms Flashcards
Reproduction, inheritance and homeostasis
hermaphrodites
An organism with both male and female reproductive organs.
what makes up the menstrual cycle
ovarian and uterine cycle
3 stages of ovarian cycle
- follicular phase
- ovulation
- luteal phase
3 stages of uterine cycle
- menstruation
- proliferation phase
- secretarial phase
double fertilisation
The two fertilisation events that occur: fusion of the first male gamete with the nucleus of the egg cell, and the fusion of the second male gamete with the two polar nuclei present in the central cell.
self- incompatibility
The inability of hermaphroditic plants to produce zygotes after self-pollination.
germination
The process that begins with the uptake of water by the seed and ends with the emergence of the radicle.
Gametogenesis
Formation of haploid gametes - spermatogenesis and oogenesis
corpus luteum
A temporary organ formed in each menstrual cycle from the ruptured follicle which secretes hormones.
zona pellucida
A layer on the outside of the oocyte made of glycoproteins. It is present in the unfertilised cell as well as in early embryo development.
corona radiata
A layer of follicular cells that surrounds the ovum.
acrosome
An organelle at the head of the sperm that contains digestive enzymes that aid fertilisation.
capacitation
Biochemical and physiological changes undergone by the sperm in order to fertilise an egg.
triple fusion
The fusion of a single male gamete with the two polar nuclei present in the central cell.
endosperm
Tissue that surrounds the developing embryo of flowering plant seeds and nourishes them.
acrosome reaction
Hydrolytic enzymes released by the acrosome digest and soften the zona pellucida, assisting fertilisation.
polyspermy
The fusion of more than one sperm with the egg.
cortical reaction
A mechanism that prevents polyspermy and involves the release of cortical granules from the fertilised egg.
cleavage
A series of rapid cell divisions undergone by a zygote.
trophoblast
Cells that will become the placenta
inner cell mass
Cells within the blastocyst that will become the embryo.
haploid
A haploid nucleus contains a single set of chromosomes. Gametes are haploid.
diploid
Cells that contain two copies of each autosome and two sex chromosomes. Diploid cells have an even number of chromosomes.
self pollination
The transfer of pollen grains to the stigma of the same flower or to the stigma of another flower on the same plant.