Plants and other autotrophs absorb nutrients from soil and water. Autotrophs are organisms that can make their own food. The most important nutrients they need are carbon, hydrogen, and oxygen. Other nutrients needed by plants are nitrogen, phosphorous, potassium, calcium, magnesium, and sulfur.
The alternation of generations
in the life cycle of a plant includes the diploid and haploid multicellular
stages. diploid and haploid are copies of the chromosomes. The spores in the
plant is unicellular and when they start dividing through mitosis, it produces
identical cells. These identical cells are all haploid. Haploid stages contain
one set of chromosome from either of the parent. These identical cells create a
multicellular system called the gametophytes. A gametophyte is the haploid
multicellular stage in the life cycle of a plant. The gametophyte makes the
gametes. These gametes are responsible for sexual fertilization. It takes place
when a sperm (male gametes) from the male fuses into the egg cell (female
gametes) of the female. The formation of both
male and female gametes creates a diploid zygote. Diploid stages
contain one set of chromosome from each parent. This is where the sporophyte
comes in. A sporophyte is the diploid multicellular stage in the life cycle of
the plant. It now contains the two sets of chromosomes from each parent.
The type of
cell division that produces gametes with half the normal chromosome number is
the meiosis. Meiosis is the type of cell division used in sexual reproduction.
It will occur in the testes and ovaries.
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Both the nitrogenous base and phosphate group are attached to the deoxyribose sugar in DNA.
