Plant cell walls are rigid membranes on the outermost part of the cell. The cell wall provides a structured shape for the cell, helping the cell retain its form and shape. The cell wall also controls the rate of replication, allowing plant cells to replicate at a much slower rate than animal cells.
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Answer
CF causes thick mucus that clogs certain organs, such as the lungs, pancreas, and intestines. This may cause malnutrition, poor growth, frequent respiratory infections, breathing problems, and chronic lung disease.
The Symptoms of Cystic Fibrosis:
Chronic coughing (dry or coughing up mucus)
Recurring chest colds.
Wheezing or shortness of breath.
Frequent sinus infections.
Very salty-tasting skin.
Answer:
The correct answer is D.
Explanation:
Mutation refers to an alteration in the nucleotide sequence of the genome found in an individual. Mutation can be beneficial, harmful or neutral. A mutation is said to be beneficial when its effects add positively to the survival of the organism. On the other hand, a mutation is described as harmful if the effects is negative or neutral if it has no negative or positive effects.
From the options given in this question, you will notice that all of them have beneficial effects with the exception of option D. A mutation that cause uncontrolled cell division is harmful and can lead to cancer.
Answer:
Leptin is a protein hormone composed of 167 amino acids of the cytosine family, it is synthesized mainly by white adipose tissue. The leptin receptor is related to that of receptors for cytosines (since it uses Janus or JAK type kinases and STAT-3 proteins as intracellular mediators of transcription pathway), it is predominantly found in the hypothalamus (particularly in the arcuate nucleus and to a lesser extent in the nuclei dorsomedial and ventromedial), hippocampus and cerebellum. There is evidence that leptin acts at the level of the arcuate nucleus, preventing the formation of NPY.
Explanation:
Leptin is produced exclusively in adipose tissue cells in a wide variety of species, including humans, and its concentration is higher in overweight than in lean individuals. The biological actions of leptin can be classified into two groups, those that are exerted in the tissues of the central nervous system, mainly the hypothalamus, and those that are carried out on the peripheral tissues. The former regulate body weight downward, decrease food intake, increase basal energy expenditure and modify some neuroendocrine functions such as reproduction, while the latter have effects on proliferation, differentiation and metabolism of peripheral tissues. The leptin that reaches the hypothalamus, in addition, inhibits protein synthesis and the secretion of neurons producing NPY / AgRP of the arcuate nucleus and stimulates the synthesis and secretion of those containing POMC. NPY (neuropeptide Y) is produced in the hypothalamic arcuate nucleus. This neurotransmitter arrives through the projections of the neurons of said nucleus to the paraventricular nucleus, which is the area where it is released. There are several studies that have shown that an increase in NPY leads to an increase in the sensation of hunger and thus to hyperphagia and obesity. Leptin acts at the level of the arcuate nucleus, preventing the formation of NPY. The leptin receptor lacks enzymatic activity in its intracellular domain. Instead, it is linked to members of the janus kinase family, which belong to a class of tyrosine kinases. The binding of the ligand activates the Jak kinase and leads to the phosphorylation of certain cytoplasmic proteins. Within these proteins there is a class of cytoplasmic transcription factors called signal transducers and activators of transcription (STAT).
During protein synthesis the cell uses information from messenger RNA
