Lecture 5 Flashcards
what is the difference between a vegetative and a generative cell
the vegetative cell forms the pollen tube whereas the generative cell forms two or three sperm cells, in the development of pollen
what is the difference between a two-celled and three celled pollen grain
two celled pollen grains only have one pollen mitosis, three celled pollen grains have two pollen mitosis
differentiate between microsporogenesis and microgametogenesis
microsporogenesis results in microspores (pollen grains); microgameteogenesis is the process in which microspores (pollen grains) divide to form the male gametes
differentiate between megasporogenesis and megagametogenesis
megasporogenesis is the process of generating the female megaspore from the megasporocyte; megagametogenesis is the process of forming the female gamete through division of the megaspore
what is coenocyte
the free nuclear state of the nuclei in a single megaspore
distinguish between the micropyle and the chalazal ends of the megaspore
the micropyle end is the end with the opening and the chalazal end is the opposite
distinguish between the antipodals and synergids and polar nuclei
antipodals are at the chalazal ends and the synergids are at the micropyle end with the egg cell. The polar nuclei are just the nucleus and are two in the middle of the megaspore
what is cellularization
the process of cell walls forming around the nuclei
what does binucleate refer to
the central polar nuclei as a single cell with two nucleuses
what constitutes the megagametophyte or embryo sac
the 8 nucleate structure in the ovules after megasporogenesis
what is double fertilization
the process in which the generative cell of the pollen tube divides into two to form two male gamete nuclei - then one nuclei fuses with the egg to form the 2n zygote and another nuclei fuses with the polar nuclei to form a 3n endosperm
how does the pollen tube enter into the ovule
through the micropyle
how many nuclei does the pollen tube contain and what are they
two - generative and vegetative
is double fertilization unique to the angiosperms
yes!
what is embryogenesis
the process in which a fertilized ovule converts into a multicellular embryo
what is a fertilized ovule called
a seed
what forms the seed coat
the integuments
what forms the fruit
development of the ovary wall and associated structures
where will the seed be hydrated
through the micropyle
what is the apical vacuolate
small, densely cytoplasmic, towards chalazal end
what is the basal vacuolate
larger vacuolate, towards micropylar end
what forms the embryo proper
division of the apical cell
what forms the suspensor and what is it
division of the basal cell (it is considered nutritive)
what is the shape of the embryo like
heart shaped, globular
what is the protoderm
skin
what is the procambium
can continue to divide
what are the apical meristems
shoot and root apical meristems; where divisions of the embryo become confined to
what makes a structure considered an embryo
a structure with two poles (SAM and RAM)
what is the funicle
tube connecting the seed to the mother tissue; maintains connectivity, gives water, gives nutrients
how are seeds dispersed
through breaking of the connection between the funicle with the mother tissue
what is a fruit
the mature ovary of single or multiple flowers and sometimes accessory structures; sometimes contains seeds
what is parthenocarpic
seedless fruits
what is a simple fruit
single carpel or multiple fused carpels (bean, tomatoes, grapes)
what is a multiple fruit
multiple fused ovaries of several flowers (pineapple, fig)
what is an aggregate fruit
severa; seperate carpels/ovaries present in a single flower merge together (strawberry, raspberry)
what is an accessory fruit
composed of floral parts other than the carpels
what is the pericarp
fruit wall around the seeds (exocarp, mesocarp, endocarp)
