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Explain the following (I) Phyllotaxy and its types
(II) Draw diagrammatic representation of Hatch and Slack pathway?
(III) Explain Functions of GH, TSH, Oestrogen in humans.
Answer
461.1k+ views
Hint: (I) Each leaf usually has a leaf blade (lamina), a midrib, and a margin. The leaves that do not have petioles are directly connected to the stem of the plant and are called sessile leaves; some of the leaves have a petiole that attaches the leaf to the stem.
(II) \[{{C}_{4}}\] One of three known photosynthetic procedures for carbon fixation is the carbon fixation or Hatch-Slack pathway.
Complete Answer:
(I) Phyllotaxy: Phyllotaxy refers to the pattern on the stem or branch of a plant or the arrangement of leaves. It is of three styles, alternate, opposite, and whorled. A single leaf emerges from the node of a branch in alternate phyllotaxy. The sunflower, mustard, and peepal are observed in this type of phyllotaxis. Plants with opposite phyllotaxy have two leaves in opposite directions, originating from the node. It can be found in guava and jam plants. There are three or four leaves emerging from the node in plants with whorled phyllotaxy. It is found in the area of Alstonia.
There are two kinds of modes of arrangement of leaves. They are:
(1) Cyclic Phyllotaxy: The leaves form a whorl at each node in the cyclic style of phyllotaxy, with the leaves positioned on a circle in which the angles between the adjacent leaves are the same.If there are more than two leaves in a whorl, the phyllotaxy is called verticillate.
(2) Phyllotaxy Spiral or Alternate or Acyclic Phyllotaxy: This is the most common form of phyllotaxy, and the mathematical control of the arrangement is surprising.
One can easily check that:
(1) The angular distance (angular divergence) between any two consecutive leaves is constant.
(2) When viewed from the top, all the leaves are found to lie in a fixed number of vertical rows or orthotics.
(3) The orthostichy is evenly distributed in a circle, the angle between the adjacent orthostichy being constant.
(4) while the leaves are scattered, close inspection reveals that the leaves are evenly dispersed on all sides of the stem.
(II) Hatch and Slack Pathway:
The Hatch and Slack pathway is a cyclical pathway for the fixation of \[C{{O}_{2}}\].
The primary \[C{{O}_{2}}\] receptor is a 3-carbon phosphoenol pyruvate (PEP) compound that is present in mesophyll cells.
PEP in mesophyll cells is transformed to oxaloacetic acid (OAA), which is then further converted to a 4-carbon compound, such as malic acid or aspartic acid, which is then transferred to the bundle sheath cells.
In the bundle sheath cells, a 3-carbon compound with the release of \[C{{O}_{2}}\] is broken down again.
(III) Growth hormone (GH), also known as somatotropin or human growth hormone, the peptide hormone secreted by the anterior pituitary gland lobe. It promotes the development of most of the body's tissues, including bone. Anterior pituitary cells called somatotrophs, which release between one and two milligrammes of the hormone every day, synthesise and secrete GH. For normal physical growth in children, GH is important; its levels increase steadily during childhood and peak during puberty growth.
TSH(Thyroid Stimulating Hormone). It targets the thyroid. Its function is to induce the thyroid gland to secrete its own hormone called thyroxine. TSH is also referred to as thyrotrophin.
Oestrogen is made by the Ovaries. Oestrogen promotes the development of sex organ tissues and other reproductive tissues. Oestrogen also acts to strengthen bones and protects the heart.
Note: (I) The number and location of the leaves of a plant can differ depending on the species, with each species having a characteristic leaf arrangement.
(II) \[{{C}_{4}}\] plants of the Kranz type anatomy. Vascular bundles are surrounded by a bundle of sheath cells. Chloroplasty is dimorphic. Bundle sheath cells have very large chloroplasts. They lack grana and they contain starch grains. They are centripetally organised and the mesophyll cells have thin and granular chloroplasts.
(II) \[{{C}_{4}}\] One of three known photosynthetic procedures for carbon fixation is the carbon fixation or Hatch-Slack pathway.
Complete Answer:
(I) Phyllotaxy: Phyllotaxy refers to the pattern on the stem or branch of a plant or the arrangement of leaves. It is of three styles, alternate, opposite, and whorled. A single leaf emerges from the node of a branch in alternate phyllotaxy. The sunflower, mustard, and peepal are observed in this type of phyllotaxis. Plants with opposite phyllotaxy have two leaves in opposite directions, originating from the node. It can be found in guava and jam plants. There are three or four leaves emerging from the node in plants with whorled phyllotaxy. It is found in the area of Alstonia.
There are two kinds of modes of arrangement of leaves. They are:
(1) Cyclic Phyllotaxy: The leaves form a whorl at each node in the cyclic style of phyllotaxy, with the leaves positioned on a circle in which the angles between the adjacent leaves are the same.If there are more than two leaves in a whorl, the phyllotaxy is called verticillate.
(2) Phyllotaxy Spiral or Alternate or Acyclic Phyllotaxy: This is the most common form of phyllotaxy, and the mathematical control of the arrangement is surprising.
One can easily check that:
(1) The angular distance (angular divergence) between any two consecutive leaves is constant.
(2) When viewed from the top, all the leaves are found to lie in a fixed number of vertical rows or orthotics.
(3) The orthostichy is evenly distributed in a circle, the angle between the adjacent orthostichy being constant.
(4) while the leaves are scattered, close inspection reveals that the leaves are evenly dispersed on all sides of the stem.
(II) Hatch and Slack Pathway:
The Hatch and Slack pathway is a cyclical pathway for the fixation of \[C{{O}_{2}}\].
The primary \[C{{O}_{2}}\] receptor is a 3-carbon phosphoenol pyruvate (PEP) compound that is present in mesophyll cells.
PEP in mesophyll cells is transformed to oxaloacetic acid (OAA), which is then further converted to a 4-carbon compound, such as malic acid or aspartic acid, which is then transferred to the bundle sheath cells.
In the bundle sheath cells, a 3-carbon compound with the release of \[C{{O}_{2}}\] is broken down again.
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(III) Growth hormone (GH), also known as somatotropin or human growth hormone, the peptide hormone secreted by the anterior pituitary gland lobe. It promotes the development of most of the body's tissues, including bone. Anterior pituitary cells called somatotrophs, which release between one and two milligrammes of the hormone every day, synthesise and secrete GH. For normal physical growth in children, GH is important; its levels increase steadily during childhood and peak during puberty growth.
TSH(Thyroid Stimulating Hormone). It targets the thyroid. Its function is to induce the thyroid gland to secrete its own hormone called thyroxine. TSH is also referred to as thyrotrophin.
Oestrogen is made by the Ovaries. Oestrogen promotes the development of sex organ tissues and other reproductive tissues. Oestrogen also acts to strengthen bones and protects the heart.
Note: (I) The number and location of the leaves of a plant can differ depending on the species, with each species having a characteristic leaf arrangement.
(II) \[{{C}_{4}}\] plants of the Kranz type anatomy. Vascular bundles are surrounded by a bundle of sheath cells. Chloroplasty is dimorphic. Bundle sheath cells have very large chloroplasts. They lack grana and they contain starch grains. They are centripetally organised and the mesophyll cells have thin and granular chloroplasts.
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