Answer:
Measurement (Count) of Cell Numbers:
1. Breed Method:
A known volume of microbial cell suspension (0.01 ml) is spread uniformly over a glass slide covering a specific area (1 sq. cm). The smear is then fixed by heating, stained, examined under oil immersion lens, and the cells are counted.
Customarily, cells in a few microscopic fields are counted because it is not possible to scan the entire area of smear. The counting of total number of cells is determined by calculating the total number of microscopic fields per one square cm. area of the smear.
Modern day whale species, have very small pelvic bones in comparison to their body size, and also they are useless. This is because this bones in the whale body are remnants from the time when their ancestors were land dwelling creatures, thus they had legs as the typical land mammal has. But during their evolution, as their ancestors were starting to adapt more to the water, the legs started to disappear, but the bones inside of the body remained, even though they were of not use. Even though millions of years had passed since this bone is useless, it still exists, and the reason for that is that there hasn't been any evolutionary pressure for it to not exist, since it is not causing any disadvantage into the movement and lifestyle of the whales.
Well the first difference is that PMS is mostly a psychological and somewhat physical syndrome. The proof is that the symptoms of PMS are irritability, stress and dysphoria. There is of course a lot of other symptoms like anxiety, insomnia, headache, fatigue, mood swings, and increased emotional sensitivity. The cause of PMS are the changes in levels of estrogen and progesterone. Now, menstrual cramps are physical condition. The symptom is pain in lower abdomen. And the cause is the menstruation itself. So there you have the differences. PMS as its own name says (Premenstrual syndrome) occurs before menstruation, more accurately 5 - 10 days before menstruation which is luteal phase of menstrual cycle. Menstrual cramps can occur several days before menstruation or can occur when menstruation starts, and they slowly disappear as menstruation slowly ends
1.Flammability
2.Solid
3.All of the above are evidence of a chemical reaction.
4.False
5.Aluminium
6.Potassium Iodide
7.False
8.Single Replacement
9.Adding more powdered drink mix
10.0.77g/cm³
Answer:
- One spermatogonium produces 4 spermatids FALSE. One primary spermatocyte produces 4 spermatids.
Explanation:
Germ cells are diploid reproductive cells in charge of gamete production. Germ cells divide by mitosis and meiosis. Through mitosis, they originate more sexual cells, but through meiosis, they produce gametes -sperm and egg cells-. This process is known as gametogenesis.
Gametes´destiny is to merge during fecundation, and a new diploid cell called zygote emerges through fertilization. The zygote is a complete cell and suffers successive mitosis to form the new organism.
Spermatogenesis is the process of production and maturation of sperm cells. Spermatogonia are the masculine diploid germ cells, carrying 46 chromosomes. These germ cells suffer mitosis to reproduce. Some of them stay as spermatogonia, and some others become primary spermatocytes, which are in charge of gamete production. Primary spermatocytes are also diploid cells, meaning that they still carry 46 chromosomes.
Each primary spermatocyte replicates its genetic material and then goes through meiosis I to produce two daughter haploid cells called secondary spermatocytes, each of them carrying 23 chromosomes. Each secondary spermatocyte will produce two other haploid daughter cells by meiosis II.
The total result from the two cellular divisions of each primary spermatocyte is four haploid daughter cells called spermatids.
During spermiogenesis, spermatids mature into spermatozoa or sperm cells. Each sperm cell characterizes by being composed of a head, midpiece, and tail.
- DNA replicates once, but cells divide twice TRUE
- The products are spermatozoa that each have a head, midpiece, and tail TRUE
- Spermatids containing 23 chromosomes (1n) are produced TRUE
- One spermatogonium produces 4 spermatids FALSE. One primary spermatocyte produces 4 spermatids.
- Genetically diverse spermatids are created TRUE
