Answer:
A mutation is a change that occurs in our DNA sequence, either due to mistakes when the DNA is copied or as the result of environmental factors such as UV light and cigarette smoke. Mutations can occur during DNA replication if errors are made and not corrected in time. Mutations can also occur as the result of exposure to environmental factors such as smoking, sunlight and radiation. Often cells can recognize any potentially mutation-causing damage and repair it before it becomes a fixed mutation.
Mutations contribute to genetic variation within species. Mutations can also be inherited, particularly if they have a positive effect. For example, the disorder sickle cell anaemia is caused by a mutation in the gene that instructs the building of a protein called hemoglobin. This causes the red blood cells to become an abnormal, rigid, sickle shape. However, in African populations, having this mutation also protects against malaria.
However, mutation can also disrupt normal gene activity and cause diseases, like cancer. Cancer is the most common human genetic disease; it is caused by mutations occurring in a number of growth-controlling genes. Sometimes faulty, cancer-causing genes can exist from birth, increasing a person’s chance of getting cancer.
Answer:
the prokaryotic virus does not have a nucleus (????) but I do think it has a membrane bound organelle. cant answer the rest. Hope this helps!!!
Explanation:
I did it in biology but the teacher was a bit of a bad teacher.
Answer: a. Haploid spores are released to form zygotes, which grow into gametophytes.
A fern has two different stages of the life cycle; the sporophyte and gametophyte. In the sporophyte, spores are released. After this life cycle comes the gametophyte or the sexual phase, <span>haploid spores are released to form zygotes, which grow into gametophytes. </span>
Answer:
The most important hormone involved in controlling sperm production is a steroid called testosterone. This is produced in the testis itself, by the Leydig cells (see Figure 12a). The testosterone is released from the Leydig cells between the tubules, and taken up by the neighbouring Sertoli cells.
