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Reproduction
Biology
Term | Definition |
---|---|
The idea behind prokaryotic reproduction | Because prokaryotes have no organelles, the single DNA molecule attaches itself to the cell membrane and duplicates itself while the cell itself grows in size. The cell then pinches inward, thus creating two identical daughter cells. |
Eukaryotic autosomal cells | Any cell that is not a sex cell, containing the diploid (2n) number of chromosomes |
Eukaryotic sex cells | Sex cells containing the haploid (n) number of chromosomes. |
G1 Stage [The Cell Cycle] | Cells create organelles for energy and protein production (mitochondria, ribosomes, and endoplasmic reticulum) while also doubling in size. |
S Stage [The Cell Cycle] | The cell replicates its genetic material so that each daughter cell will have identical copies. |
Chromatids | After replication, each chromosome consists of two identical chromatids. A single chromosome (a stick) replicates to form two sister chromatids (an X). We have 46 chromosomes and 92 chromatids |
G2 Stage [The Cell Cycle] | Containing twice as much DNA as cells in G1, this stage makes sure there is enough organelles and cytoplasm for the division and creation of two daughter cells. |
Cytokinesis | The splitting of the cytoplasm and organelles into the daughter cells |
Mitosis | (Ending in two identical diploid daughter cells) The process of the division of the cell consisting of the phases: -Prophase -Metaphase -Anaphase -Telophase |
Prophase | Chromosome condense and spindles form |
Metaphase | Chromosomes align |
Anaphase | Sister chromatids separate |
Telophase | New nuclear membranes form |
Centrioles | These organelles migrate to opposite poles of the cell and begin to form spindle fibers |
Spindle fibers | Fibers that radiate outward from the centrioles, giving the chromosomes an attachment point for later separation during anaphase |
Binary Fission | (Think bacteria) [Asexual reproduction] The circular chromosome attaches to the cell wall and replicates while the cell continues to grow in size. Eventually the cell will pinch, and two identical daughter cells are formed |
Budding | [Asexual reproduction] Budding is EQUAL replication followed by UNEQUAL cytokinesis. In other words, the daughter cell receives DNA identical to her parent's but far less cytoplasm. |
Regeneration | (think of a liver transplant) [Asexual reproduction] The ability for an organism to regrow certain parts/cells after they have been removed |
Parthogenesis | [Asexual reproduction] The process whereby an adult organism develops an unfertilized egg. |
Gametes | Specialized sex cells used in sexual reproduction |
Meiosis | (Ending in 4 different haploid (n) gametes) The process of the division of the cell consisting of the phases: -Prophase I & II -Metaphase I & II -Anaphase I & II -Telophase I & II |
Prophase I (Meiosis) | Homologous chromosomes come together and intertwine in a process called synapsis. Consisting of a pair of homologous chromosomes containing four chromatids, these chromatids may go through crossing over |
Crossing over | Chromatids of homologous chromosomes may break at the point of synapsis and exchange equivalent pieces of DNA |
Metaphase I (Meiosis) | Homologous pairs align at the metaphase plate and each pair attaches to separate spindle fiber by its kinetochore. (Side by side X's) |
Anaphase I (Meiosis) | Homologous pairs separate and are pulled to opposite poles of the cell. A random distribution, with respect to parental origin, of the homologous chromosomes creates a unique pool of alleles |
Telophase I (Meiosis) | A nuclear membrane forms around each nucleus. Each daughter cell is now haploid |
Prophase II (Meiosis) | The centrioles migrate to opposite poles, and the spindle apparatus forms |
Metaphase II (Meiosis) | The chromosomes line up along the metaphase plate. The centromeres divide, separating the chromosomes into pairs of sister chromatids |
Anaphase II (Meiosis) | Sister chromatids are pulled to opposite poles by the spindle fibers |
Telophase II (Meiosis) | A nuclear membrane forms around each new (haploid) nucleus. Cytokinesis follows, and two daughter cells are formed. Thus by the completion of meiosis II, four haploid daughter cells are produced per gametocyte. |
Zygote | The initial cell formed when two gametes (sex cells) join together |
Seminiferous tubules | The site where sperm are produced and nourished by Sertoli cells |
Leydig cells | Secrete testosterone and other male sex hormones (androgen) |
Epididymis | Transports and stores cells that were produced in the testes |
Seminal vesicles | Contribute fructose to nourish sperm |
Prostate gland | Gives the seminal fluid mildly alkaline properties so it will survive the relative acidity of the female reproductive tract |
The pathway of sperm (Creation --> Ejaculation) | Seminiferous tubules --> Epididymis --> Vas deferens --> Ejaculatory duct --> (Nothing) --> Urethra --> Penis (SEVEN UP) |
Spermatogenesis | Spermatogonia (2n) --> 1^ Spermatocytes (2n) [go through meiosis I] --> 2^ Spermatocytes (n) [go through meiosis II] --> Spermatids (n) --> Spermatozoa (n) |
Oogenesis | 1^ Ooctye (2n) [Undergoes meiosis I] --> *a polar body* 2^ Oocyte (n) [Undergoes fertilization][Undergoes meisosis II] --> Ovum (n) |