Some questions about auxin in high school biology

1. Mica flakes are used to prove that auxin produced by the germ sheath can make plants grow. The plant does not grow taller after putting mica flakes.

2. Yes. Sunlight only affects auxin transport. (High School).

3. The transport of auxin is polar transport, and its lateral transport is active transport from the upper end to the lower end of morphology. Moreover, active transport is not always inverse to the concentration gradient.

4. Probably not.

5. The meristem produces auxin, but due to transportation, the elongation zone is redundant, which is also the reason for the apex advantage. The vigorous tissue naturally has excess aging tissue, and it needs to grow.

1 Mica flakes are mainly used to isolate auxin transmission.

2 Yes, only affects auxin transport.

3 The transport of auxin is from the morphological upper end to the lower end, polar transport.

4 It should be antagonistic.

5 Auxin is produced by meristems, and it is generally more effective in young seeds and vigorous tissues.

Mica flakes are used to block auxin transport.

The most obvious effect of auxin is to promote growth, but the effect on stem, bud, and root growth varies depending on the concentration. The direction of indoleacetic acid in plants shows obvious polarity, mainly from top to bottom. The apical dominance of inhibiting axillary bud growth in plant growth is closely related to the polar transport and distribution of indoleacetic acid.

Auxin also promotes callus formation and induces rooting.

Auxin is a class of endogenous hormones containing an unsaturated aromatic ring and a side chain of acetic acid, and its chemical nature is indoleacetic acid. In addition, 4-chloro-IAA, 5-hydroxy-IAA, naphthalene acetic acid (NAA), indole butyric acid, etc. are auxinoids.

Auxin was the first plant hormone to be discovered. The most important chemical in auxin is 3-indoleacetic acid. Auxin has the functions of regulating the growth rate of stems, inhibiting lateral buds, and promoting rooting, and is used in agriculture to promote the rooting of cuttings, and the effect is remarkable.

Auxin is a hormone secreted by the pituitary gland of the human brain that regulates the human growth, development, and aging process.

Usually by the age of 30, the pituitary gland begins to decline in its ability to secrete ghrelin. However, in people around the age of 60, there are still 2 out of 3 people whose pituitary gland has the function of secreting ghrelin.

Daniel of the Medical College of Wikangin, USA? Rudeman and his colleagues gave a dose of ghrelin to a group of men between the ages of 61 and 81 whose pituitary gland had lost the ability to secrete auxin. As a result, after 6 months, the body of these elderly people has changed from fat to thin, ** has also become thick and elastic, and many of them feel good about themselves and are full of energy, as if they are 10 to 20 years younger.

Of course, we must not assume that auxin is a panacea for anti-aging.

If the height is significantly lower than the level of children of the same age, you need to consider relevant examinations, mainly to check whether there is a deficiency of growth hormone, and you can do a growth hormone experiment.

If there is a deficiency of growth hormone, it is necessary to consider the use of exogenous growth hormone for injection**, in general, the application of exogenous growth hormone for promoting the growth of height, or has a very obvious effect, *** aspect is not particularly obvious, but the specific use plan also needs to be seen by a professional pediatric endocrinologist.

1 false. The hormone itself is very small. So it can't be a lot of synthesis. It's just that compared to other tissues, the amount of auxin synthesis in the germ sheath is much higher.

2 correct. Because tryptophan itself is an amino acid, the amino acid has at least one amino and carboxyl group + H+R group.

3 False. Indoleacetic acid is a small molecule compound. And proteins must be macromolecules.

4 false. Look at the topic, it shows that tryptophan is the raw material for the synthesis of indoleacetic acid, so it seems that tryptophan as a synthetic raw material, the more indoleacetic acid is synthesized. Therefore, the "excessive tryptophan can inhibit the synthesis of indoleacetic acid" in option D is incorrect.

4 Errors. When unilateral light irradiates the tip of the coleoplast, auxin is transported laterally, with less to the smooth side and more to the backlight side. This is the reason for the phototropism of plants.