- Xylem contains tracheids, vessels, xylem parenchyma and xylem fibre.
- Tracheids: They are elongated, tubular dead cells with tapering end walls.
- Vessels: These are also known as trachea. They are elongated, tubular dead cells. They are joined to each other by end to end forming a continuous pipe. The cells are thick and lignified.
- Xylem parenchyma: They are also called wood parenchyma. This is the only living tissue of xylem.
- Xylem fibre: They are dead cells with thick walled fibre.
- Phloem consists of sieve tubes, companion cells, phloem parenchyma and phloem fibres.
- Sieve tubes: These are elongated, tubular living cells arranged in a row, with their perforated end walls forming a sieve. They are non-nucleated. Their protoplasm are inter-connected through sieve plates. They possess vacuoles.
- Companion cell: They are elongated, lens-shaped cells containing dense cytoplasm and prominent nuclei. These cells maintain connection with sieve cells through pits.
- Phloem parenchyma: They are living thin walled parenchyma cells.
- Phloem fibre: They are also known as bast fibre. They are elongated fibre like sclerenchymatous dead cells with thick walls containing pits and interlocked ends. Phloem fibre are the only dead cells in phloem.
Hope you could get an idea from here.
Doubt clarification - use comment section.
Answer:
Clomid tricks the body because it tells the brain that estrogen levels are low, thereby leading to higher production of this hormone
Explanation:
There are many types of hormones that are regulated by the negative feedback mechanism (where hormone feeds back to decrease its production). Clomid is a drug used to treat female infertility by making the body think that the concentration of estrogen is low, which induces the secretion of Follicle-stimulating (FSH) and luteinizing (LH) hormones by the pituitary gland. The estrogen hormone exerts negative feedback on the Gonadotropin-releasing (GnRH) hormone, which is responsible for the release of FSH and LH. High FSH levels stimulate the growth of follicles in the ovaries, which will be released during ovulation.
<span>olive oil,canola oil,peanut oil,safflower oil and.<span>sesame oil.
I know that is more than 3, but you can just pick 3 examples from the list</span></span>
Answer:
c) It introduces a premature stop codon into the mRNA
Explanation:
Nonsense mutation is a type of point mutation (single nucleotide base is changed) which leads to premature stop codon. Stop codons are also called nonsense codons and that is way this type of mutation is called nonsense mutation. As a consequence, synthesized protein is incomplete and shorter than it should be (truncated protein), usually nonfunctional.
Answer:
The phenotype is the result of the interaction between the genes (i.e., genotype) and environmental factors.
Explanation:
Cancer is a disease caused by abnormal expression of genes involved in the cell cycle, mitosis, DNA replication, etc. Moreover, the abnormal gene expression may be associated with environmental factors such as smoking, alcohol consumption, etc.
