Biology Class XI

LOCOMOTION AND MOVEMENT – PART 4

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Thoracic Cage: Thoracic vertebrae, sternum and ribs form a bony thoracic (chest) case for protection of lungs and heart. The Sternum: It is narrow, elongated and flattened. It forms the anterior (front) part of chest cage. It consists of three parts – uppermost (superior) manubrium (prosternum), middle body (mesosternum) and lowermost (inferior) xiphoid process (metasternum).  ...
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Biology Class XI

LOCOMOTION AND MOVEMENT – PART 3

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The Skeletal System The human endoskeleton is made up of bones and cartilage of various types. It is composed of 206 (213 in children) separate bones distributed as follows: Axial Skeleton: It forms the upright axis of body and includes 80 (87 in children) bones as follows: Cranium 8 Face 14 Ear ossicles 6 Hyoid ...
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Biology Class XI

LOCOMOTION AND MOVEMENT – PART 2

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Sarcotubular system The sarcolemma folds inwards and forms a system of tubes, which run through sarcoplasm to the Z lines. This system of tubes is called the T system or T tubules. The cisterns of sarcoplasmic reticulum are present on either side of T tubules. These structures form the sarcotubular system. The function of the ...
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Biology Class XI

LOCOMOTION AND MOVEMENT – PART 1

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Most animals move about from one place to another by swimming, flying or walking. To move, all animals use the same basic mechanism: muscle contraction. Movement especially on land is complicated by gravity which tends to hold objects in one place. Therefore, it becomes essential that a force is applied to overcome gravity. For a ...
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Biology Class XI

NEET NOTES – CHAPTER 11 – TRANSPORT IN PLANTS – PART 4

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STOMATAL OPENING & CLOSING Opening and closing of stomata is controlled by accumulation of solutes in the guard cells. In the guard cells the microfibrils are oriented radially, making it easier for the stoma to open. Solutes are taken up by the guard cells from the neighboring cells. As a result the osmotic potential and ...
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Biology Class XI

NEET NOTES – CHAPTER 11 – TRANSPORT IN PLANTS – PART 3

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This causes water to move into the sieve-tube element by osmosis, creating pressure that pushes the sap down the tube. In sugar sinks, cells actively transport solutes out of the sieve-tube elements, producing the exactly opposite effect. Organic molecules such as sugars, amino acids, certain hormones, and even messenger RNAs are transported in the phloem ...
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Biology Class XI

NEET NOTES – CHAPTER 11 – TRANSPORT IN PLANTS – PART 2

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RELATIONSHIP BETWEEN WATER, SOLUTE AND PRESSURE POTENTIAL Water potential of a cell is affected by both solute and pressure potential. The relationship between them is as follows: OSMOSIS Diffusion of water through a semi permeable membrane is known as osmosis. The diffusion of water molecules continues across the membrane until an equilibrium is reached. At ...
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Biology Class XI

NEET NOTES – CHAPTER 11 – TRANSPORT IN PLANTS – PART 1

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TRANSPORT IN PLANTS Plants have a transport system, in some ways similar to an animal’s blood circulatory system. However, it is rather different in several important ways. For example, there is no pump like the heart, no circulating cells and liquids do not continuously move round and round. The substances which are transported – mineral ...
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Biology Class XI

NEET NOTES – CHAPTER 14 – RESPIRATION IN PLANTS – PART 3

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THE RESPIRATORY BALANCE SHEET The calculations of net gain of ATP for every molecule of glucose oxidised are based on certain assumptions. These are: Glycolysis, TCA cycle and ETS pathways occur in a sequence with one substrate forming another in an orderly manner. NADH formed in glycolysis undergoes oxidative phosphorylation in mitochondria. None of the ...
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Biology Class XI

NEET NOTES – CHAPTER 14 – RESPIRATION IN PLANTS – PART 2

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STEPS of TCA CYCLE Condensation. Acetyl CoA combines with oxaloacetate to form citrate in the presence of enzyme citrate synthetase. Acetyl CoA is a 2-carbon compound, oxaloacetate is 4-carbon compound and citrate is 6-carbon tricarboxylic acid. Isomerization. Citrate is converted into its isomer isocitrate in a two step reaction in the presence of iron containing ...
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