Term
| What are the four stages of the cell cycle for an actively dividing cell? What cell cycle would a nondividing cell be in? |
|
Definition
| G1, S, G2 and M are the four phases in that order. The first three are known collectively as interphase. G0 is an offshoot of G1 that nondividing cells are in. |
|
|
Term
| What happens during G1 stage? |
|
Definition
| Cell is creating more organelles and growing in size. Checkpoint between G1 and S phase makes sure cell DNA is in good enough condition for synthesis before going into S phase. |
|
|
Term
|
Definition
| The cells replicates DNA. Twice as many chromatids now (92) but the same number of chromosomes (46). |
|
|
Term
| What happens in G2 Stage? |
|
Definition
| Another quality control checkpoint checks for organelles, cytoplasm and correct DNA replication |
|
|
Term
| What are the four phases of mitosis? |
|
Definition
| prophase, metaphase, anaphase and telophase |
|
|
Term
|
Definition
| cells that aren't involved in sexual reproduction |
|
|
Term
| What happens during prophase? |
|
Definition
- Chromosomes condense
- Nuclear membrane dissolves
- Nucleoli disappear
- centiroles migrate to centrosomes
- Spindle apparatus begins to form and
- Kinetochores at centromere are contacted by spindle fiber
|
|
|
Term
| What happens during metaphase? |
|
Definition
- chromosomes line up along metaphase plate
|
|
|
Term
| What happens during anaphase? |
|
Definition
| Sister chromatids are pulled apart to opposite poles of cell |
|
|
Term
| What happens during telophase? |
|
Definition
| Nuclear membrane reforms, spindle apparatus disappears, and cytosol and organelles are split by cytokinesis |
|
|
Term
|
Definition
| Cell division for gameotcytes (germ cells) to produce gametes |
|
|
Term
| What happens in prophase I of meiosis? |
|
Definition
Similar to prophase of mitosis: chromatin condenses into chromosomes, spindle apparatus forms, nuclear membrane disappears.
Major differences: homologous chromosomes come together and intertwine (synapsis) forming a tetrad. Crossing over occurs which leads to homologous recombination to create genetic diversity. |
|
|
Term
| What happens in anaphase I of meiosis? |
|
Definition
| Homologous pairs are pulled to opposite poles. The daughter cells could end up with the paternal or maternal copy of a chromosome resulting in more diversity. This is called segregation. |
|
|
Term
| What happens in metaphase I of meiosis? |
|
Definition
| Homologous pairs align at the metaphase plate. This differs from mitosis in that homologous chromosomes are lining up across from each other rather than a single chromosome. |
|
|
Term
| What happens in telophase I of meiosis? |
|
Definition
| Nuclear membranes reform. Cells are now haploid. Cytokinesis occurs. |
|
|
Term
| What happens during meiosis II? |
|
Definition
| same as mitosis except it is using only 23 sister chromatids and not 46. Each cell cycle phase occurs the same. |
|
|
Term
|
Definition
| found in testes, produce testosterone, aka cells of Leydig |
|
|
Term
| What cells produce testosterone? |
|
Definition
| Leydig or interstitial cells |
|
|
Term
| What is the function of the seminiferous tubules? |
|
Definition
| Sperm production and growth. Sperm are nourished by Sertoli cells. |
|
|
Term
|
Definition
| nourish developing sperm cells |
|
|
Term
| Where are sperm stored until ejaculation? |
|
Definition
| Epididymis, also where flagella gain motility |
|
|
Term
| What is the path of sperm from production to ejaculation? |
|
Definition
1. Seminiferous tubules
2. Epididymis
3. Vas deferens
4. Ejaculatory Duct
5. Urethra
|
|
|
Term
| What fluids mix with the sperm and what produces those fluids? |
|
Definition
- Seminal vesicles - fructose for energy and mild alkalinity
- Prostate gland - mild alkalinity to counteract acidity of vagina
- Bulbourethral (Cowper's) glands - clear viscous fluid to lubricate urethra
|
|
|
Term
| What are the stages of spermatogenesis? |
|
Definition
Spermatogonia (diploid)
(replicate DNA)
Primary spermatocytes (diploid)
(meiosis I)
Secondary spermatoctyes
(meiosis II)
Spermatids (immature)
(maturation)
Spermatozoa
|
|
|
Term
| What hormones do the ovaries produce? |
|
Definition
| estrogen and progesterone |
|
|
Term
| What is the process of oogenesis? |
|
Definition
oogonium
(replication occurs before birth)
primary oocytes (arrested in prophase I)
(ovulation)
secondary oocyte
(fertilization, completes meiosis II)
ovum
Unequal cytokinesis occurs in meiosis I and II for oocytes to give the main one most of the cytoplasm and organelles. |
|
|
Term
| What hormone triggers the onset of puberty and what restricts the production of that hormone? |
|
Definition
| Gonadotropin-releasing hormone (GnRH) and its production is restricted by the hypothalamus. Once puberty starts the hypothalamus send GnRH to the anterior pituitary. |
|
|
Term
| What hormones are released that trigger sexual development? |
|
Definition
| Hypothalamus releases gonadotropin-releasing hormone (GnRH) which triggers the anterior pituitary gland to synthesize and release follicle-stimulating hormone (FSH) and luteinizing hormone (LH). These hormones trigger the production of other sex hormones. |
|
|
Term
| What is the male sexual hormone and what secondary sexual characteristics do males show? |
|
Definition
| Testosterone from testes (interstitial cells) causes facial and axillary hair, deepening of the voice and changes in growth patterns. Luteinizing hormone stimulates interstitial cells to produce testosterone. Follicle stimulating hormone stimulate Sertoli cells and triggers sperm maturation. |
|
|
Term
| What hormones are the female sex hormones and what do they do? |
|
Definition
Follicle stimualting hormone causes estrogens to release causing breasts, widening of the hips, changes in fat distribution. Also causes thickening of endometrium.
Luteinizing hormone causes corpus luteum to release progesterone which helps develop and maintain the endometrium. |
|
|
Term
| What are the 4 phases of the menstrual cycle and what characterizes each? |
|
Definition
1. Follicular phase - begins when menstrual flow begins. GnRH increases due to low estrogen levels which causes FSH and LH production to increase which stimulate ovarian follicles to produce estrogen. Increase in estrogen has negative feedback on GnRH, FSH and LH
2. Ovulation - estrogen production keeps increasing to the point the it has a positive feedback affect on GnRH, LH and FSH. The spike in LH causes ovulation (release of the ovum from ovary)
3. Luteal Phase - LH makes ruptured follicle form corpus luteum which secretes progesterone (endometrium maintenance). Estrogen levels stay high and progesterone increases. Negative feedback on GnRH, FSH and LH to prevent second egg from being released.
4. Menstruation - No implantation = no LH which causes corpus luteum to stom producing progesterone which is mainting the endometrium. This cuases uterine lining to shed. Decrease in estrogen and progesterone causes increase in GnRH and the cycle starts over.
5. Pregnancy - if implantation occurs the blastocyst will secret humn chorionic gonadotropin (hCG), an analog of LH meaning it will maintain the corpus luteum until the placenta grows large enough to secrete its own progesterone and estrogen. |
|
|
