The sporophyte is the diploid multicellular generation of a plant, which makes spores by meiosis.
Missing Word
sporophyte
The sporophyte is the diploid phase of the plant life cycle. It forms from the zygote and produces haploid spores, which grow into gametophytes.
Category: Plant Life Cycles
Question 2
The antheridium is the male gametangium that produces and releases flagellated sperm in seedless plants.
Missing Word
antheridium
An antheridium is the sperm-producing organ of a gametophyte. In mosses and ferns its sperm must swim through water to reach the egg.
Category: Plant Life Cycles
Question 3
A sporangium is the structure in which diploid sporocytes divide by meiosis to form haploid spores.
Missing Word
sporangium
A sporangium, meaning spore vessel, is the multicellular structure where spores are made. It protects developing spores, a key adaptation to life on land.
Category: Plant Life Cycles
Question 4
The outer walls of spores and pollen grains contain sporopollenin, an extremely durable polymer that resists drying and decay.
Missing Word
sporopollenin
Sporopollenin is one of the toughest biological materials known. It protects spores and pollen from drying out and is why they fossilize so well.
Category: Land Adaptations
Question 5
A meristem is a region of undifferentiated cells that keep dividing throughout a plant's life, producing new tissues at places such as shoot and root tips.
Missing Word
meristem
A meristem is plant tissue that stays able to divide. Meristems at the tips lengthen shoots and roots, while those along the sides thicken stems and trunks.
Category: Land Adaptations
Question 6
The large, often divided leaves of ferns are called fronds.
Missing Word
fronds
Fronds are fern leaves. Young fronds uncurl as they grow, and many fronds carry clusters of sporangia on their undersides.
Category: Seedless Vascular Plants
Question 7
Horsetails belong to the single living genus Equisetum, whose green stems have jointed nodes ringed by whorls of thin leaves.
Missing Word
Equisetum
Equisetum is the only surviving genus of horsetails. Its hollow, jointed stems carry out most of the plant's photosynthesis, and its relatives formed tree-sized forests in the past.
Category: Seedless Vascular Plants
Question 8
Pines, spruces, firs, and sequoias are all conifers, the largest group of gymnosperms.
Missing Word
conifers
Conifers are cone-bearing gymnosperms, usually trees with needle-like or scale-like leaves. They dominate many cold and high-altitude forests.
Category: Gymnosperms
Question 9
Angiosperms enclose their seeds inside an ovary, which ripens into a fruit, and they are the most diverse group of land plants.
Missing Word
Angiosperms
Angiosperms are the flowering plants. Their name means vessel seed, referring to the ovary that surrounds the seeds, and they include more species than any other plant group.
Category: Angiosperms
Question 10
A cotyledon is a seed leaf that passes stored food to the young plant, and eudicot embryos have two of them.
Missing Word
cotyledon
A cotyledon is a leaf that is already part of the embryo in a seed. The number of cotyledons, one in monocots and two in eudicots, is one way of telling the two groups apart.
Category: Angiosperms
Question 11
Each stamen, the male reproductive organ of a flower, consists of a filament topped by an anther.
Missing Word
stamen
A stamen is the pollen-producing organ of a flower. Meiosis in its anther produces microspores that develop into pollen grains.
Category: Angiosperms
Question 12
Each sepal is one of the usually green, leaflike parts that enclose a flower bud before it opens.
Missing Word
sepal
A sepal is a part of the outermost whorl of a flower. Together the sepals form the calyx, which protects the bud and is often photosynthetic.
Category: Angiosperms
Question 13
In flowering plants, pollination is the transfer of pollen from an anther to a stigma.
Missing Word
pollination
Pollination moves pollen to the female part of a flower. It can happen by wind or water, but most flowering plants rely on animals such as insects, birds, or bats.
Category: Angiosperms
Question 14
A dioecious species bears its male flowers and its female flowers on separate individual plants.
Missing Word
dioecious
Dioecious species have separate male and female plants, so pollen must travel between individuals. In contrast, monoecious species carry both kinds of flowers on one plant.
Category: Angiosperms
Question 15
Quinine, a drug obtained from the bark of the cinchona tree, has long been used to treat malaria.
Missing Word
Quinine
Quinine is a plant alkaloid from cinchona bark and was one of the first effective treatments for malaria. It is one of many medicines that come from plant secondary metabolites.
Category: Plants and People