Heredity - Part I

Asexual Reproduction

process of using a single parent organism or cell to create offspring that are genetically identical to the parent

Sexual Reproduction

process by which two different parent cells produce genetically diverse offspring

Genetic Diversity

occurs when there is a variety of genes within an organism or group of organisms

Binary Fission

form of asexual reproduction in unicellular organisms where one cell divides to form two genetically identical cells

Mitotic Cell Division

process that involves the duplication and separation of DNA to form two new cells cells that are genetically identical

Meiotic Cell Division

form of cell reproduction where one cell divides to form 4 genetically diverse daughter cells after two rounds of cell division

Fertilization

process during sexual reproduction in which haploid male and female cells join to form a new diploid cell

1n

symbol for haploid number of chromosomes in a cell

2n

symbol for the diploid number of chromosomes in a cell, which occurs when chromosomes all have a homologous partner

Germ Cells

reproductive cells that undergo meiosis to develop into sperm and ova

Primary Sex Cell

diploid cell that undergoes meiotic cell division to produce monoploid gametes

Testes

male gonads where sperm cells and androgens are produced

Ovaries

female gonads that produce eggs and release reproductive hormones

Oocyte

type of cell in an ovary that may undergo meiotic division to form an egg

Spermatocyte

cell produced in the formation of sperm cells, formed from a spermatogonium and dividing by meiosis into a mature sperm cell

Oogonia

immature female reproductive cell that gives rise to ova by meiosis

Spermatogonia

diploid cells in a testis that can give rise to sperm cells after meiosis

Gametes

haploid reproductive cells that may undergo fertilization to form a zygote

Puberty

period of sexual maturation, during which a person becomes capable of producing reproductive hormones and gametes

Hypothalamus

brain structure that directs maintenance activities (eating, drinking, body temperature), helps govern the endocrine system via the pituitary gland, and is linked to emotion and behavior

Pituitary Gland

endocrine gland at the base of the brain that releases hormones to control the activity of other glands

Sex Chromosomes

final pair of chromosomes that determine the sex of an individual; typically X and Y

Spermatogenesis

production of sperm cells in the testes, which includes meiosis

Acrosome

region at the head of a sperm cell that contains digestive enzymes to penetrate the egg, as well as glycoproteins for recognition during fertilization

Flagellum

tail-like structure on the sperm cell that provides movement

Vas Deferens

tubes within the male reproductive tract that transfer sperm cells to the glands that provide supporting fluids

Seminal Vesicle and Prostate Gland

Structures in the male reproductive system that secrete fluids to support sperm cells with energy and proper pH

Epididymis

small pouch found within the male reproductive tract for the storage of mature sperm cells

Ovum

mature egg cell that contains 1/2 of the female's genetic information

Mitochondria and Chloroplast

organelles that are found in the mature ovum, which are only contributed by the mother

Cortical Granules

small vesicles found next to the cell membrane, which are used to "seal" the egg once it is fertilized and prevent fertilization by multiple sperm cells

Zona Pellucida

outer layer of the mature ovum that contains many glycoproteins for identification and compatibility with the sperm cell

Internal Fertilization

process in which eggs and sperm cells meet inside the female's body, protected from the outside environment and improving the likelihood of forming a zygote

Internal Development

growth and maturation of the embryo within the body of the female, which increases the likelihood of survival for offspring

Fallopian Tube

female structure that connects the ovary to the uterus, which is also the site of fertilization

Uterus

female organ of reproduction used to provide nutrients and remove waste during development of the fetus

Endometrium

inner lining of the uterus where the fertilized egg implants and attaches at the start of pregnancy

Ovulation

process of releasing a mature ovum into the fallopian tube each month, providing an opportunity for fertilization

Zygote

diploid cell resulting from the fusion of two haploid gametes

Gametogenesis

process by which gametes are produced through the combination of meiosis and other structural changes

Equation Division

second division of meiosis where the chromosome number is not altered, but double chromosomes become single chromosomes

Reduction Division

occurs during Meiosis I, when homologous pairs of chromosome separate and the chromosome number is reduced by half

Ploidy

number of sets of chromosomes in a cell, ex. 1n, 2n, 3n

Diploid

organism or cell having two sets of chromosomes, or twice the haploid number

Homologues

two chromosomes that code for the same traits; typically creating a pair of paternal and maternal copies

Haploid

organism or cell having only one complete set of chromosomes

Monoploid

similar ploidy as a haploid cell or organism

Oogenesis

process including meiosis that leads to the production, growth, and maturation of an egg, or ovum

Polar Bodies

cells produced in females that do not complete maturation during oogenesis and do not participate in reproduction

Tetrads

paired homologous chromosomes that attach to one another during Prophase I of meiosis

Synapsis

attachment of chromatids from homologous chromosomes during Prophase of Meiosis I

Crossing Over

exchange of genes between homologous chromosomes, resulting in a mixture of parental characteristics and recombinant chromosomes

Homologous Chromosomes

chromosomes that have the same size, shape, and genes, which are the only types of chromosomes that can undergo Crossing Over

Recombinant Chromosomes

chromosomes that carry genes from each parent, which are formed as a result of Crossing Over

Independent Assortment

random distribution of alleles to the gametes during meiosis, which increases the number of allele combinations in gametes

Crossing Over and Independent Assortment

processes that occur during meiosis to increase genetic diversity in gametes and the resulting offspring

Meiotic Cell Division

form of cell division that is used to create

genetically diverse cells and reduce ploidy

Mitotic Cell Division

form of cell division that is used to create

genetically identical cells and maintain ploidy

Sporophyte

diploid organism that uses meiosis to create haploid spores for reproduction

Gametophyte

haploid organism that uses mitosis to create haploid gametes for reproduction

Estrogen

primary hormone that is responsible for the development of the uterus during the menstrual cycle

Menstrual Cycle

regular sequence of events in which an egg is prepared for fertilization and the uterus is prepared for fetal development

Progesterone

female hormone that maintains the uterine lining for potential implantation of the zygote

FSH and LH

hormones that are responsible for the maturation of gametes, such as sperm and ova, in males and females

Testosterone

most important of the male sex hormones that stimulates the production of sperm cells in reproductive males, as well as the determination of sex of the fetus during development