Meiosis and Mitosis Processes and Sexually Transmitted Diseases

Cell Division Processes: Mitosis and Meiosis

Mitosis and meiosis go through the same steps of interphase, prophase, metaphase, anaphase, telophase, and cytokinesis. Interphase is when the chromatins duplicate in the nucleus. Then it goes on to prophase where the chromatins coil into chromosomes, the nuclear membrane dissolves, and spindle fibers form. I will mention later a difference that occurs in prophase I of meiosis but not during the prophase stage of mitosis. During metaphase, the chromosomes are pulled to the middle of the cell by the spindle fibers, and in mitosis, the tetrads are pulled to the middle of the cell. During anaphase of mitosis, the chromosomes split apart into chromatids and are pulled to opposite sides of the cell. During meiosis, the tetrads are pulled apart back into chromosomes and pulled to opposite sides of the cell. Then during telophase, the nuclear membrane redevelops around the genetic material. Around the end of the anaphase stage, cytokinesis begins which is the division of the cytoplasm. The cell begins to split at the end of anaphase and continues after the end of telophase.

Comparative Analysis of Meiosis and Mitosis

The interesting thing is that meiosis goes through these same steps, but twice. There are also a few variations between the two processes and the steps they take to complete their cell divisions. The first thing to note about the differences in these two processes is that mitosis is the division of regular body cells and meiosis is the division of a sperm or egg cell. The next thing that is different is that mitosis is the division of a mother diploid cell with forty-six chromosomes into two daughter diploid cells, both with forty-six chromosomes that are identical to the mother. Meiosis takes a mother diploid cell with forty-six chromosomes and divides it into four haploid cells with twenty-three chromosomes each. Meiosis achieves genetic diversity by going through all of those stages twice. Another difference occurs during prophase. During mitosis, the chromosomes line up by themselves, single file in the middle of the cell. During meiosis, the chromosomes line up two by two in what is called tetrads through a process called synapsis, which I will come back to in a moment. Later down the road in anaphase, another variation occurs between these two. During mitosis, the chromosomes split apart into what are called chromatids. During anaphase in meiosis, the tetrads split apart back into chromosomes.

The Role of Synapsis and Crossing Over

As I said before, synapsis is the process during meiosis where the chromosomes come together to form tetrads. Synapsis is important because it allows for another process called crossing over. Crossovers occur within each tetrad when the free end of one maternal and one paternal (as they are colloquially called) chromatids wrap around each other at one or more points. This allows for the exchange of genetic material between the two chromatids. This only occurs in prophase I, not in prophase II, any other stage of meiosis, or mitosis. The genetic recombination resulting from crossing over is essential for evolution and adaptation, as it increases genetic variability among organisms.

Sexually Transmitted Diseases: A National Health Concern

Sexually transmitted diseases, or STDs, are one of the biggest problems that we face as a nation today, for the mere fact that everyone loves sex. The most common bacterial sexually transmitted disease is called chlamydia. It affects the cervix in women and both the urethra and rectum in men. It can also show no symptoms, which is problematic because chlamydia that is left untreated can cause serious problems later in life. Some symptoms that appear in women are pain during sexual intercourse and bleeding after, lower abdomen pains, irregular menstrual bleeding, more frequent need to urinate, pain while passing urine, and an increased vaginal discharge due to an inflamed cervix. In men, the symptoms present as a white/cloudy watery discharge from the penis that may stain the underwear, a burning sensation or pain while passing urine, and pain and swelling in the testicles. Men are more likely to notice the symptoms as opposed to females who may be asymptomatic. Chlamydia can be passed through unprotected vaginal, oral, or anal sex (Centers for Disease Control and Prevention [CDC], 2022).

Understanding Syphilis: The Great Imitator

Syphilis is another STD that can be called “the great imitator” because its symptoms look like symptoms for so many other diseases. The symptoms of syphilis in adults can be divided into stages. The first stage is when you notice a sore on the location where you received the infection. When you find it, you must get it treated before it moves on to the second stage. In the second stage, you will develop a rash as the sore of the initial infection site is healing. The rash will either be on the palms of your hands or on the soles of your feet. It will be painless and won’t itch. The final stage is called the latent stage where there won’t be any symptoms. The patient won’t notice any symptoms for 10-30 years, but then they will have problems coordinating their muscle movements, possible paralysis, numbness, blindness, and dementia. It is very important to get your syphilis treated (World Health Organization [WHO], 2021).

Gonorrhea: Recognizing the Symptoms

Another STD is known as gonorrhea, which can infect the urethra, cervix, anus, rectum, and throat. It presents itself as a burning sensation when peeing, a yellow/white discharge from the penis, a change in vaginal discharge, and irritation or discharge from the anus if the rectum is infected. These symptoms present themselves from one to fourteen days after coming in contact with the infection. Men are also more likely to notice the symptoms than women (CDC, 2022).

Herpes: A Viral Infection with Lasting Effects

Herpes is caused by two different strains of the herpes simplex virus. HSV-1 is more likely to manifest itself on the mouth and lips. HSV-2 is the more common one, which affects the genital area as well as the anal area. Symptoms occur after two to seven days and last from two to four weeks. Symptoms include itching or tingling sensations in the genital or anal area, small fluid-filled blisters that burst leaving small painful sores, pain when passing urine over the open sores, which is especially true of women, headaches, backache, and flu-like symptoms including swollen glands or fever. The virus lies dormant in the body until periods of stress that bring it out for shorter, less painful periods of times (Mayo Clinic, 2023).

Molluscum Contagiosum: A Viral Skin Disease

Molluscum contagiosum is another viral infection that occurs as a result of having sex. It results in a skin disease where small pearl-shaped papules appear in clusters on the skin. These papules are filled with gungy, white, contagious fluid. It is not strictly an STD, but can be passed by direct skin-to-skin contact, sharing a bath, sharing clothing, or other means. It can show up in kids as well, particularly in kids who are prone to skin diseases such as eczema. Transmission can be prevented by wearing a condom (though it doesn’t always help because the disease is spread by any kind of skin-to-skin contact), not sharing clothes, towels, or baths, and not coming into skin-to-skin contact with someone who is infected. The best policy for this STD is not only abstinence, but also avoiding skin-to-skin contact with an infected person as well as indirect contact with an infected person. An important thing to note is that in a person who is HIV positive, an outbreak of molluscum contagiosum could mean the weakening of the immune system (American Academy of Dermatology Association [AAD], 2022).

References

American Academy of Dermatology Association. (2022). Molluscum contagiosum: Diagnosis and treatment. Retrieved from https://www.aad.org/public/diseases/a-z/molluscum-contagiosum-treatment

Centers for Disease Control and Prevention. (2022). Chlamydia - CDC fact sheet (detailed). Retrieved from https://www.cdc.gov/std/chlamydia/stdfact-chlamydia-detailed.htm

Mayo Clinic. (2023). Herpes simplex virus. Retrieved from https://www.mayoclinic.org/diseases-conditions/herpes-simplex-virus/symptoms-causes/syc-20356158

World Health Organization. (2021). Syphilis. Retrieved from https://www.who.int/news-room/fact-sheets/detail/syphilis