sexual reproduction Flashcards
what is a diploid zygote?
A fertilized egg
how does a diploid zygote form?
when an egg and sperm fuse together
how many stages are there in sexual reproduction and what are they?
there are three stages in sexual reproduction which are mating fertilization and development
what is mating
when two individuals come together to have sexual intercourse and produce offspring where the sperm cells enter inside the reproductive system and arrive at the egg cell
what is fertilization
when a haploid sperm cell fuses with the haploid egg cell to produce a diploid zygote(fertilized egg cell)
how many types of fertilization are there and name them?
there are two types of fertilization, internal fertilization and external fertilization
describing internal fertilization
when the sperm cell is deposited inside the female reproductive system meets the egg cell fertilization occurs when the female egg cell meets the sperm cell (at the fallopian tube)
describe external fertilization
it occurs when the sperm cell in the egg cells unite outside the bodies of the parents. sperm is released by the male and eggs are released by the female. ex: male releases his sperm over female eggs fusion between eggs and sperm occurs
explain development
the diploid zygote begins mitosis and undergoes rapid cell division on its way to becoming a fetus in humans, a full pregnancy is 39 to 40 weeks
what are some problems that can occur in pregnancy?
mei 1 : homologous chromosomes fail to separate and in meiosis 2 the sister chromatids fail to separate, one gamete will have two copies of one chromosome the other will have no copy of that chromosomes
what happens if a gamete with two copies of one one chromosome fuses with a normal gamete?
possible the offspring will have a genetic disorder called down syndrome (in down syndrome the offspring has 3 copies of chromosome 21)
what is a karyotype
a picture of an organisms chromosomes arranged in a particular order (doctors use karyotypes to diagnose and treat patients with genetic disorders)
advantages and disadvantages of sexual reproduction compared to asexual
advantages: genetic diversity, offsprings genetically different from parents
disadvantage: energy required to find mate and produce gametes, fewer offsprings produced and increase of mutation
advantages and disadvantages of internal fertilization
advantages: more protection given to embryo, more parental care
disadvantage: fewer offspring produced, energy to find mate
advantages and disadvantages of external fertilization
advantages: little energy is required to find a mate
disadvantages: unprotected embryo and often preyed upon large quantities of eggs and sperm and required
