BIOL3304 Ch 03: Meiosis

Meiosis

A type of cell division that creates gametes with half the number of chromosomes.

Gametes

Reproductive cells (sperm and oocytes) that are haploid.

Germ line cells

Cells that give rise to gametes by undergoing meiosis.

Diploid

Cells that contain two complete sets of chromosomes.

Haploid

Cells that contain one set of chromosomes.

Spermatogenesis

The process of sperm cell development.

Oogenesis

The process of egg (ovum) development.

Fertilization

The union of sperm and oocyte to form a zygote.

Zygote

The fertilized egg that results from the union of sperm and oocyte.

Cleavage

Early cell divisions that occur after fertilization.

Blastocyst

A hollow ball of cells formed during early embryonic development.

Trophoblast

The outer layer of the blastocyst that helps with implantation.

Inner cell mass

The cluster of cells inside the blastocyst that will develop into the embryo.

Gastrula

The three-layered structure formed after the blastocyst stage, consisting of ectoderm, mesoderm, and endoderm.

Ectoderm

The outermost germ layer, which develops into skin and nervous system.

Mesoderm

The middle germ layer, which develops into muscles and bones.

Endoderm

The innermost germ layer, which develops into digestive and respiratory systems.

Critical period

A phase in prenatal development when certain structures are particularly susceptible to disruption.

Teratogens

Agents that can cause birth defects during prenatal development.

Spermatogonium

A diploid germ cell that divides to create sperm.

Prophase I

The stage of meiosis where homologous chromosomes pair and exchange genetic material.

Crossing over

The exchange of genetic material between homologous chromosomes during prophase I, increasing genetic diversity.

Independent assortment

The random distribution of homologous chromosomes during meiosis.

Acrosome

The cap-like structure that contains enzymes to help sperm penetrate the oocyte.

Acrosomal enzymes

Enzymes that facilitate sperm penetration into the oocyte.

Spermatozoa

Mature sperm cells that are produced at the end of spermatogenesis.

Oogonium

A diploid germ cell that undergoes meiosis to form oocytes.

Secondary oocyte

The larger cell produced in the first meiotic division of oogenesis.

Polar body

The small cell produced during oogenesis that does not develop into a fertilizable ovum.

Fetal alcohol syndrome

A condition resulting from alcohol exposure during pregnancy, leading to physical and developmental issues.

Paternal age effect

The increased risk of mutations in sperm as a male ages.

Progeroid syndromes

Genetic disorders that result in accelerated aging.

Achondroplasia

A genetic disorder causing short-limbed dwarfism.

Crouzon syndrome

A genetic condition causing premature fusion of skull bones.

Hutchinson-Gilford progeria syndrome

A severe form of accelerated aging caused by a mutation in the LMNA gene.

Longevity genes

Genes associated with increased lifespan and resistance to age-related diseases.

Fertilized ovum

The single cell formed by the fusion of sperm and oocyte.

Oocyte maturation

The process by which immature eggs develop into mature ovum ready for fertilization.

Somatic cells

Any body cell that is not a reproductive cell.

Mitosis

A type of cell division that results in two identical daughter cells.

Meiosis I

The first division of meiosis that reduces chromosome number by half.

Meiosis II

The second division of meiosis that equates to mitosis, producing four haploid cells.

Embryonic period

The stage from fertilization to 8 weeks when most organs begin to form.

Prenatal development

The development of a human during the prenatal period, divided into embryonic and fetal stages.

Neural tube

The embryonic structure that eventually develops into the brain and spinal cord.

SRY gene

The gene responsible for the development of male characteristics.

Gene mutations

Changes in the DNA sequence that can affect gene function.

In vitro fertilization

A process by which an egg is fertilized by sperm outside the body.

Amniotic fluid

The fluid that surrounds the developing fetus, providing protection.

Umbilical cord

The structure that connects the fetus to the placenta.

Placenta

An organ that develops during pregnancy to provide nutrient and waste exchange between the mother and fetus.

Stem cells

Undifferentiated cells that can develop into various cell types.

Folic acid

A vitamin necessary for proper cellular division and development during pregnancy.

Genetic diversity

The total number of genetic characteristics in the genetic makeup of a species.

Maturation

The process of development and differentiation that occurs in living organisms.

Aging

The process of becoming older which often involves biological changes.