51.2 Gametogenesis and Fertilization

51.2 Gametogenesis and Fertilization

• Animals that reproduce sexually are less likely to have moderately deleterious genes.

• The hypothesis died and did not reproduce.

• Approximately how many times did deleterious mutations persist in the asexually reproducing sexual populations but not in the asexual ones.

• Starts with cells called germ cells.

• The development of sperm and eggs is similar to the formation of gametes.
• In this section, we will look at the differences between the two types of gamete.

• In species with separate sexes, males have testes and females have mature haploid sperm cells.
• Some animal species result in four gametes from each spermatogonium.

• Male diploid (2n) germ cells undergo two meiotic divisions to produce mature haploid sperm.
• The head, midpiece, and flagellum of a mature human sperm can be seen in a drawing and scanning electron micrograph.
• The process of oogenesis in females, which produces a haploid secondary oocyte that enters but does not complete meiosis II until it is fertilized.
• The drawing depicts a secondary oocyte within its follicle, while theSEM shows an isolated human oocyte covered by its zona pellucida and remnants of the cumulus mass.
• The structure of a sperm cell is an example of the core concept of biology.
• The sperm cell's structural elements are suited for a specific function.
• The sperm is capable of fertilization when all three elements are working together.

• Each spermatocyte has a different oocyte in it.
• The tail mass, also known as the flagellum, is a layer of cells outside of the sperm that provides protection and support.
• The tail needs energy to make zona pellucida.
• The sperm motile is produced by an outer cellular layer called the theca.
• The head region of the sperm contains mones that control oocyte growth.
• The nucleus carries the chromosomes.
• Important roles in fertilization can be found at the tip of the head.

• Fertilization is the process by which the haploid male and female gam on the species are able to reproduce.

• Four gametes are produced by spermatogenesis.
• The oogenesis begins in the ovary of a female embryo.
• The oogonia divide by attracting nearby sperm.
• This increases the number of primary oocytes that enter meiosis I but stops the process of respiration within the arrested state after birth.
• Meiosis does not resume until the sperm is present.
• The time after puberty when a mammal first becomes capable of reproducing by following the concentration of attractants is when the sperm swims.

• A polar body is a smaller cell.
• The sperm must start in the secondary oocytes but stop at the metaphase in Meiosis II sea urchins.
• If sperm are available, the sperm is able to do this.
• The second meiotic division doesn't happen if the oocyte doesn't encounter the acrosome.
• A diploid zygote is produced when the nucleus is dissolved by these enzymes.

• The sperm head ian structure is fused after binding.

• The sperm-binding acrosome and the vitelline hydrolytic enzymes that bind to the egg are destroyed by the contents of the cortical 3.

• A series of events allow the head of the sperm to bind to the egg.
• The vitelline layer of the egg is prevented from being fused by an increased concentration of Ca2+.