BIOL 325 Final Exam Questions and
Answers 2024
what are theca? - The typical anther is bilocular, i.e. it consists of two thecae. Each
theca contains two microsporangia
What are microsporangia? - Are the pollen sacs. Microsporangia produce the
microspores, which for seed plants are known as pollen grains
How many theca and sporangia are part of each anther? - Theca: 2
Microsporangia: 4
What separates the two theca? - A longitudinal groove
What are the pollen sacs lined with? - tapetum cells
What are tapetum cells? - Nutrition
What is microsporogenesis? - After meiosis haploid microspores in the pollen sacs
undergo several changes
-Microspore divides once by meiosis to produce two cells
-small generative cell is formed inside larger cell
-Tetrad of microspores separate from each other
-A two-layered wall develops around each spore
-in 2/3 of flowering plant species pollen grain is released at the 2 cell stage
, -For others, the generative cell divides to produce 2 sperm resulting in a 3-celled
microgametophyte
What is reduced male gametophyte? - Another apomorphy of angiosperms is a
reduced 3-celled male gametophyte- no other plant group has a male gametophyte
so reduced in cell number
What is Mature microgametophyte? - germinated pollen grain, with tube nucleus
and 2 sperm cells
What is pollination? - Transfer of the pollen grains to the stigmas.
-Pollen grains hydrate
-Germinate: forming pollen tube
-Pollen tube grows through stigma to ovules
What happens if the generative cell remains undivided? - Divides to form 2 sperm
cells
What is double fertilization? - -Pollen tube enters ovule through micropyle
-then enters 1 of the synergids
-2 sperm and tube nucleus discharged into synergid
-1 sperm enters the egg cell- fertilization
-Other sperm enters central cell and unites with 2 polar nuclei
-tube nucleus, remaining synergid and antipodals degenerate
Definition of double fertilization - The union of one sperm with the egg and the
other with the polar nuclei is called double fertilization
Answers 2024
what are theca? - The typical anther is bilocular, i.e. it consists of two thecae. Each
theca contains two microsporangia
What are microsporangia? - Are the pollen sacs. Microsporangia produce the
microspores, which for seed plants are known as pollen grains
How many theca and sporangia are part of each anther? - Theca: 2
Microsporangia: 4
What separates the two theca? - A longitudinal groove
What are the pollen sacs lined with? - tapetum cells
What are tapetum cells? - Nutrition
What is microsporogenesis? - After meiosis haploid microspores in the pollen sacs
undergo several changes
-Microspore divides once by meiosis to produce two cells
-small generative cell is formed inside larger cell
-Tetrad of microspores separate from each other
-A two-layered wall develops around each spore
-in 2/3 of flowering plant species pollen grain is released at the 2 cell stage
, -For others, the generative cell divides to produce 2 sperm resulting in a 3-celled
microgametophyte
What is reduced male gametophyte? - Another apomorphy of angiosperms is a
reduced 3-celled male gametophyte- no other plant group has a male gametophyte
so reduced in cell number
What is Mature microgametophyte? - germinated pollen grain, with tube nucleus
and 2 sperm cells
What is pollination? - Transfer of the pollen grains to the stigmas.
-Pollen grains hydrate
-Germinate: forming pollen tube
-Pollen tube grows through stigma to ovules
What happens if the generative cell remains undivided? - Divides to form 2 sperm
cells
What is double fertilization? - -Pollen tube enters ovule through micropyle
-then enters 1 of the synergids
-2 sperm and tube nucleus discharged into synergid
-1 sperm enters the egg cell- fertilization
-Other sperm enters central cell and unites with 2 polar nuclei
-tube nucleus, remaining synergid and antipodals degenerate
Definition of double fertilization - The union of one sperm with the egg and the
other with the polar nuclei is called double fertilization
