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55ea5547-8880-4e58-b88b-7d3adcca8f8a | # UNIT 5
# HUΜΑN PHYSIOLOGY
# Chapter 14
The reductionist approach to study of life forms resulted in increasing use of physico-chemical concepts and techniques. Majority of these studies employed either surviving tissue model or straightaway cell-free systems. An explosion of knowledge resulted in molecular biology... | 0 | 11 | Biology | 14 |
1caa948f-7189-44a2-b988-fb8457a7670c | # Alfonso Corti
# (1822 – 1888)
ALFONSO CORTI, Italian anatomist, was born in 1822. Corti began his scientific career studying the cardiovascular systems of reptiles. Later, he turned his attention to the mammalian auditory system. In 1851, he published a paper describing a structure located on the basilar membrane o... | 1 | 11 | Biology | 14 |
a39661db-c721-4182-9970-eced62cc402d | # CHAPTER 14
# BREATHING AND EXCHANGE OF GASES
# 14.1 Respiratory Organs
As you have read earlier, oxygen (O2) is utilised by the organisms to indirectly break down simple molecules like glucose, amino acids, fatty acids, etc., to derive energy to perform various activities. Carbon dioxide (CO2) which is harmful is ... | 2 | 11 | Biology | 14 |
740a549d-28f8-403b-ad68-0d2b355d660f | # 14.1.1 Human Respiratory System
We have a pair of external nostrils opening out above the upper lips. It leads to a nasal chamber through the nasal passage. The nasal chamber opens into the pharynx, a portion of which is the common passage for food and air. The pharynx opens through the larynx region into the trache... | 3 | 11 | Biology | 14 |
f567ec42-1678-4de1-b26e-8c16fa86dc70 | # BREATHING AND EXCHANGE OF GASES
The lining whereas the inner pleural membrane is in contact with the lung surface. The part starting with the external nostrils up to the terminal bronchioles constitute the conducting part whereas the alveoli and their ducts form the respiratory or exchange part of the respiratory sy... | 4 | 11 | Biology | 14 |
f36d0331-d3fa-48a8-b100-f421db183b41 | # BIOLOGY
sternum causing an increase in the volume of the thoracic chamber in the dorso-ventral axis. The overall increase in the thoracic volume causes a similar increase in pulmonary volume. An increase in pulmonary volume decreases the intra-pulmonary pressure to less than the atmospheric pressure which forces the... | 5 | 11 | Biology | 14 |
ef005014-9a2c-45c5-abb1-17d7dc0c8a2b | # BREATHING AND EXCHANGE OF GASES
Residual Volume (RV): Volume of air remaining in the lungs even after a forcible expiration. This averages 1100 mL to 1200 mL.
By adding up a few respiratory volumes described above, one can derive various pulmonary capacities, which can be used in clinical diagnosis.
Inspiratory Ca... | 6 | 11 | Biology | 14 |
36c6f889-a006-44ae-b6bc-741b631d5b3a | # BIOLOGY
# Figure 14.3
Diagrammatic representation of exchange of gases at the alveolus and the body tissues with blood and transport of oxygen and carbon dioxide a gradient is present for CO2 in the opposite direction, i.e., from tissues to blood and blood to alveoli. As the solubility of CO2 is 20-25 times higher ... | 7 | 11 | Biology | 14 |
ed7c9da8-a1c8-4a54-acdc-ada978dc8167 | # BREATHING AND EXCHANGE OF GASES
# 14.4 TRANSPORT OF GASES
Blood is the medium of transport for O2 and CO2. About 97 per cent of O2 is transported by RBCs in the blood. The remaining 3 per cent of O2 is carried in a dissolved state through the plasma. Nearly 20-25 per cent of CO2 is transported by RBCs whereas 70 pe... | 8 | 11 | Biology | 14 |
9bd7e874-7290-4c15-a755-2ddb96d86360 | # 190
# BIOLOGY
of CO2 from carbamino-haemoglobin takes place, i.e., CO2 which is bound to haemoglobin from the tissues is delivered at the alveoli. RBCs contain a very high concentration of the enzyme, carbonic anhydrase and minute quantities of the same is present in the plasma too. This enzyme facilitates the foll... | 9 | 11 | Biology | 14 |
44c378ac-22fd-499b-8494-0b23c3937270 | # BREATHING AND EXCHANGE OF GASES
# Occupational Respiratory Disorders
In certain industries, especially those involving grinding or stone-breaking, so much dust is produced that the defense mechanism of the body cannot fully cope with the situation. Long exposure can give rise to inflammation leading to fibrosis (pr... | 10 | 11 | Biology | 14 |
1cd340d6-5227-401c-9914-05d9a718611e | # BIOLOGY
# EXERCISES
1. Define vital capacity. What is its significance?
2. State the volume of air remaining in the lungs after a normal breathing.
3. Diffusion of gases occurs in the alveolar region only and not in the other parts of respiratory system. Why?
4. What are the major transport mechanisms for CO2? Expl... | 11 | 11 | Biology | 14 |
9abb4ec0-448d-4480-b25e-7f0d27e87219 | # BIOLOGY
# CHAPTER 2
# BIOLOGICAL CLASSIFICATION
# 2.1 Kingdom Monera
Since the dawn of civilisation, there have been many attempts to classify living organisms. It was done instinctively not using criteria that were scientific but borne out of a need to use organisms for our own use – for food, shelter and clothi... | 0 | 11 | Biology | 02 |
1a36ee9c-08fd-49ce-bff3-fba16e288198 | # BIOLOGICAL CLASSIFICATION
# Table 2.1 Characteristics of the Five Kingdoms
|Characters|Monera|Protista|Fungi|Plantae|Animalia|
|---|---|---|---|---|---|
|Cell type|Prokaryotic|Eukaryotic|Eukaryotic|Eukaryotic|Eukaryotic|
|Cell wall|Noncellulosic (Polysaccharide + amino acid)|Present in some|Present with chitin|Pres... | 1 | 11 | Biology | 02 |
afc1f573-7896-42a8-a07f-d59de9079711 | # BIOLOGY
in their walls while the green plants had a cellulosic cell wall. When such characteristics were considered, the fungi were placed in a separate kingdom – Kingdom Fungi. All prokaryotic organisms were grouped together under Kingdom Monera and the unicellular eukaryotic organisms were placed in Kingdom Protis... | 2 | 11 | Biology | 02 |
0903779a-22b0-472b-b84b-6d0374dfbcfe | # BIOLOGICAL CLASSIFICATION
Though the bacterial structure is very simple, they are very complex in behaviour. Compared to many other organisms, bacteria as a group show the most extensive metabolic diversity. Some of the bacteria are autotrophic, i.e., they synthesise their own food from inorganic substrates. They ma... | 3 | 11 | Biology | 02 |
900c2fdd-b601-4e25-b4a9-15f9eb8e0c3b | # BIOLOGY
roots, etc. Some are pathogens causing damage to human beings, crops, farm animals and pets. Cholera, typhoid, tetanus, citrus canker are well known diseases caused by different bacteria.
Bacteria reproduce mainly by fission (Figure 2.3). Sometimes, under unfavourable conditions, they produce spores. They a... | 4 | 11 | Biology | 02 |
20cfe69d-d8ee-495d-aac4-1f1a0a36c7c4 | # 2.2.2 Dinoflagellates
These organisms are mostly marine and photosynthetic. They appear yellow, green, brown, blue or red depending on the main pigments present in their cells. The cell wall has stiff cellulose plates on the outer surface. Most of them have two flagella; one lies longitudinally and the other transve... | 5 | 11 | Biology | 02 |
71ed6fc8-87d5-4951-ab71-b36e0c3f8e33 | # 16
# BIOLOGY
their prey by putting out pseudopodia (false feet) as in Amoeba. Marine forms have silica shells on their surface. Some of them such as Entamoeba are parasites.
Flagellated protozoans: The members of this group are either free-living or parasitic. They have flagella. The parasitic forms cause diseases... | 6 | 11 | Biology | 02 |
ca84ea11-a599-45bb-acf0-3097d237a100 | # BIOLOGICAL CLASSIFICATION
called conidia or sporangiospores or zoospores, and sexual reproduction is by oospores, ascospores and basidiospores. The various spores are produced in distinct structures called fruiting bodies. The sexual cycle involves the following three steps:
1. Fusion of protoplasms between two mot... | 7 | 11 | Biology | 02 |
46e929ae-40da-40d3-aa82-9147b446e012 | # BIOLOGY
is branched and septate. The asexual spores are conidia produced exogenously on the special mycelium called conidiophores. Conidia on germination produce mycelium. Sexual spores are called ascospores which are produced endogenously in sac like asci (singular ascus). These asci are arranged in different types... | 8 | 11 | Biology | 02 |
b2be69e9-ca28-4aab-b543-19ec67ff689e | # 2.4 KINGDOM PLANTAE
Kingdom Plantae includes all eukaryotic chlorophyll-containing organisms commonly called plants. A few members are partially heterotrophic such as the insectivorous plants or parasites. Bladderwort and Venus fly trap are examples of insectivorous plants and Cuscuta is a parasite. The plant cells ... | 9 | 11 | Biology | 02 |
0a532fa3-72ce-4e3d-ba6b-d3403edada10 | # BIOLOGY
# Head
# Collar
# Sheath
# RNA
# Capsid
# Tail fibres
Figure 2.6 (a) Tobacco Mosaic Virus (TMV)
Figure 2.6 (b) Bacteriophage
Once they infect a cell they take over the machinery of the host cell to replicate themselves, killing the host. Would you call viruses living or non-living?
Virus means venom... | 10 | 11 | Biology | 02 |
83d67d9c-a7f6-45e9-8033-bcbca290b483 | # BIOLOGICAL CLASSIFICATION
# Viroids
In 1971, T.O. Diener discovered a new infectious agent that was smaller than viruses and caused potato spindle tuber disease. It was found to be a free RNA; it lacked the protein coat that is found in viruses, hence the name viroid. The RNA of the viroid was of low molecular weig... | 11 | 11 | Biology | 02 |
9cc71d5d-aaa4-4336-b592-ea0ceb7b9f30 | # BIOLOGY
# EXERCISES
1. Discuss how classification systems have undergone several changes over a period of time?
2. State two economically important uses of:
heterotrophic bacteria
3. archae bacteria
What is the nature of cell-walls in diatoms?
Find out what do the terms ‘algal bloom’ and ‘red-tides’ signify.
How ... | 12 | 11 | Biology | 02 |
3b84d832-c051-477d-98d6-f9d7401dc0e1 | # EXCRETORY PRODUCTS AND THEIR ELIMINATION
# 16.1 Human Excretory System
Animals accumulate ammonia, urea, uric acid, carbon dioxide, water and ions like Na+, K+, Cl–, phosphate, sulphate, etc., either by metabolic activities or by other means like excess ingestion. These substances have to be removed totally or part... | 0 | 11 | Biology | 16 |
5c5e1509-18e2-46f4-922f-459c41b7ad17 | # 206
# BIOLOGY
A survey of animal kingdom presents a variety of excretory structures. In most of the invertebrates, these structures are simple tubular forms whereas vertebrates have complex tubular organs called kidneys. Some of these structures are mentioned here. Protonephridia or flame cells are the excretory st... | 1 | 11 | Biology | 16 |
87609fa4-433c-4b16-949d-af6ad89e4c00 | # EXCRETORY PRODUCTS AND THEIR ELIMINATION
medullary pyramids as renal columns called Columns of Bertini (Figure 16.2).
Each kidney has nearly one million complex tubular structures called nephrons (Figure 16.3), which are the functional units. Each nephron has two parts – the glomerulus and the renal tubule. Glomeru... | 2 | 11 | Biology | 16 |
8b6169ec-1a18-49d2-ba2d-3de9d142a077 | # 208
# BIOLOGY
Afferent arteriole (PCT). A hairpin shaped Henle’s loop is the next part of the tubule which has a descending and an ascending limb. The ascending limb continues as another highly coiled tubular region called distal convoluted tubule (DCT). The DCTs of many nephrons open into a straight tube called co... | 3 | 11 | Biology | 16 |
a5a23022-36aa-4945-ad65-16d7ef9f69ba | # EXCRETORY PRODUCTS AND THEIR ELIMINATION
The amount of the filtrate formed by the kidneys per minute is called glomerular filtration rate (GFR). GFR in a healthy individual is approximately 125 ml/minute, i.e., 180 litres per day!
The kidneys have built-in mechanisms for the regulation of glomerular filtration rate... | 4 | 11 | Biology | 16 |
cfcbbcdf-34a6-422a-a6c3-f7ea5993c52a | # BIOLOGY
Figure 16.5 Reabsorption and secretion of major substances at different parts of the nephron (Arrows indicate direction of movement of materials.)
Collecting Duct: This long duct extends from the cortex of the kidney to the inner parts of the medulla. Large amounts of water could be reabsorbed from this reg... | 5 | 11 | Biology | 16 |
c5983e7a-9356-4e70-b813-d58ab7e314cc | # EXCRETORY PRODUCTS AND THEIR ELIMINATION
also in a counter current pattern. The proximity between the Henle’s loop and vasa recta, as well as the counter current in them help in maintaining an increasing osmolarity towards the inner medullary interstitium, i.e., from 300 mOsmolL–1 in the cortex to about 1200 mOsmolL... | 6 | 11 | Biology | 16 |
5b9f42cc-534e-4d24-a2b4-78ee6648e508 | # 212
# BIOLOGY
in the medullary interstitium. Presence of such interstitial gradient helps in an easy passage of water from the collecting tubule thereby concentrating the filtrate (urine). Human kidneys can produce urine nearly four times concentrated than the initial filtrate formed.
# 16.5 REGULATION OF KIDNEY F... | 7 | 11 | Biology | 16 |
97be34c9-de9c-4d2b-93f9-9418c571eb5c | # EXCRETORY PRODUCTS AND THEIR ELIMINATION
to initiate the contraction of smooth muscles of the bladder and simultaneous relaxation of the urethral sphincter causing the release of urine. The process of release of urine is called micturition and the neural mechanisms causing it is called the micturition reflex. An adu... | 8 | 11 | Biology | 16 |
5ee4c64b-9d9a-466b-90e0-52a78ea81ea2 | # BIOLOGY
composition as that of plasma except the nitrogenous wastes. The porous cellophane membrance of the tube allows the passage of molecules based on concentration gradient. As nitrogenous wastes are absent in the dialysing fluid, these substances freely move out, thereby clearing the blood. The cleared blood is... | 9 | 11 | Biology | 16 |
99385017-9205-458f-bd40-a63b95498e1a | # EXCRETORY PRODUCTS AND THEIR ELIMINATION
minute (GFR). JGA, a specialised portion of the nephrons, plays a significant role in the regulation of GFR. Nearly 99 per cent reabsorption of the filtrate takes place through different parts of the nephrons. PCT is the major site of reabsorption and selective secretion. HL ... | 10 | 11 | Biology | 16 |
e8d1aec8-e3aa-4a56-b70b-854298c3f22e | # BIOLOGY
1. What is meant by the term osmoregulation?
2. Terrestrial animals are generally either ureotelic or uricotelic, not ammonotelic, why?
3. What is the significance of juxta glomerular apparatus (JGA) in kidney function?
4. Name the following:
1. A chordate animal having flame cells as excretory structures
2.... | 11 | 11 | Biology | 16 |
b463f15d-f25d-4c1d-b298-5b3e1cc86f76 | # CHAPTER 15
# BODY FLUIDS AND CIRCULATION
# 15.1 Blood
You have learnt that all living cells have to be provided with nutrients, O2 and other essential substances. Also, the waste or harmful substances produced, have to be removed continuously for healthy functioning of tissues. It is therefore, essential to have e... | 0 | 11 | Biology | 15 |
5737b263-2fa7-4f4b-ad50-4fd46a834ce3 | # 194
# BIOLOGY
Fibrinogens are needed for clotting or coagulation of blood. Globulins primarily are involved in defense mechanisms of the body and the albumins help in osmotic balance. Plasma also contains small amounts of minerals like Na, Ca++, Mg++, HCO3, Cl, etc. Glucose, amino acids, lipids, etc., are also pres... | 1 | 11 | Biology | 15 |
31fb6660-ec65-4c97-91eb-7e441f095b1f | # BODY FLUIDS AND CIRCULATION
associated with allergic reactions. Lymphocytes (20-25 per cent) are of two major types – ‘B’ and ‘T’ forms. Both B and T lymphocytes are responsible for immune responses of the body.
Platelets also called thrombocytes, are cell fragments produced from megakaryocytes (special cells in th... | 2 | 11 | Biology | 15 |
9e6bacc6-b40e-4145-b3b8-cd444f4fffd0 | # 15.1.3.2 Rh grouping
Another antigen, the Rh antigen similar to one present in Rhesus monkeys (hence Rh), is also observed on the surface of RBCs of majority (nearly 80 per cent) of humans. Such individuals are called Rh positive (Rh+ve) and those in whom this antigen is absent are called Rh negative (Rh-ve). An Rh-... | 3 | 11 | Biology | 15 |
c6877830-21d8-44e8-bb58-893cdfd6ff52 | # 15.2 LYMPH (TISSUE FLUID)
As the blood passes through the capillaries in tissues, some water along with many small water soluble substances move out into the spaces between the cells of tissues leaving the larger proteins and most of the formed elements in the blood vessels. This fluid released out is called the int... | 4 | 11 | Biology | 15 |
55c2de27-3ce3-4746-84b1-6d8795399fc6 | # 15.3.1 Human Circulatory System
Human circulatory system, also called the blood vascular system consists of a muscular chambered heart, a network of closed branching blood vessels and blood, the fluid which is circulated.
Heart, the mesodermally derived organ, is situated in the thoracic cavity, in between the two ... | 5 | 11 | Biology | 15 |
13d5e726-c059-45f3-9cb1-72f7233dbdd0 | # BODY FLUIDS AND CIRCULATION
The pulmonary artery and the aorta respectively are provided with the semilunar valves. The valves in the heart allow the flow of blood only in one direction, i.e., from the atria to the ventricles and from the ventricles to the pulmonary artery or aorta. These valves prevent any backward... | 6 | 11 | Biology | 15 |
75a98dea-765d-43fc-a093-8690bec4a78d | # BIOLOGY
bicuspid valves due to attempted backflow of blood into the atria. As the ventricular pressure increases further, the semilunar valves guarding the pulmonary artery (right side) and the aorta (left side) are forced open, allowing the blood in the ventricles to flow through these vessels into the circulatory ... | 7 | 11 | Biology | 15 |
ef7a5484-7cb8-4e1f-8dfe-4fce47709d6d | # BODY FLUIDS AND CIRCULATION
Figure 15.3), a patient is connected to the machine with three electrical leads (one to each wrist and to the left ankle) that continuously monitor the heart activity. For a detailed evaluation of the heart’s function, multiple leads are attached to the chest region. Here, we will talk on... | 8 | 11 | Biology | 15 |
b7f76e5b-db7c-40b4-a493-d5499cf9698b | # 202
# BIOLOGY
The hepatic portal system. The hepatic portal vein carries blood from intestine to the liver before it is delivered to the systemic circulation. A special coronary system of blood vessels is present in our body exclusively for the circulation of blood to and from the cardiac musculature.
# Figure 15.... | 9 | 11 | Biology | 15 |
e77166bd-36d2-43f6-9f02-a1a39a2a2390 | # BODY FLUIDS AND CIRCULATION
Higher, it shows hypertension. High blood pressure leads to heart diseases and also affects vital organs like brain and kidney.
# Coronary Artery Disease (CAD)
Coronary Artery Disease, often referred to as atherosclerosis, affects the vessels that supply blood to the heart muscle. It is... | 10 | 11 | Biology | 15 |
2872c153-5413-4a8a-bfa2-11972898fe95 | # 204
# BIOLOGY
The body surface by using electrocardiograph and the recording is called electrocardiogram (ECG) which is of clinical importance. We have a complete double circulation, i.e., two circulatory pathways, namely, pulmonary and systemic are present. The pulmonary circulation starts by the pumping of deoxyg... | 11 | 11 | Biology | 15 |
00eeecce-1d19-4178-b167-91522c13fb89 | # CHAPTER 7
# STRUCTURAL ORGANISATION IN ANIMALS
# 7.1 Organ and Organ System
In the preceding chapters you came across a large variety of organisms, both unicellular and multicellular, of the animal kingdom. In unicellular organisms, all functions like digestion, respiration and reproduction are performed by a sing... | 0 | 11 | Biology | 07 |
aabd61b9-aa40-4a16-90a9-31573207f7b5 | # BIOLOGY
Organ in our body is made of one or more type of tissues. For example, our heart consists of all the four types of tissues, i.e., epithelial, connective, muscular and neural. We also notice, after some careful study that the complexity in organ and organ systems displays certain discernable trend. This disce... | 1 | 11 | Biology | 07 |
61ecd897-1e65-4b15-8adf-f1c2f67ae7c2 | # STRUCTURAL ORGANISATION IN ANIMALS
swimming, walking, leaping and burrowing. The hind limbs end in five digits and they are larger and muscular than fore limbs that end in four digits. Feet have webbed digits that help in swimming. Frogs exhibit sexual dimorphism. Male frogs can be distinguished by the presence of s... | 2 | 11 | Biology | 07 |
421e6b5a-4f28-4387-8220-b36e1098b764 | # BIOLOGY
containing digestive enzymes. Food is captured by the bilobed tongue. Digestion of food takes place by the action of HCl and gastric juices secreted from the walls of the stomach. Partially digested food called chyme is passed from stomach to the first part of the small intestine, the duodenum. The duodenum ... | 3 | 11 | Biology | 07 |
904a2e8e-8622-4833-89e1-6c2c91fd3f38 | # STRUCTURAL ORGANISATION IN ANIMALS
The oviduct opens separately in the cloaca. The thin-walled urinary bladder is present ventral to the rectum which also opens in the cloaca. The frog excretes urea and thus is a ureotelic animal. Excretory wastes are carried by blood into the kidney where it is separated and excret... | 4 | 11 | Biology | 07 |
4c615ac3-52ec-461a-932a-5104b4119811 | # BIOLOGY
canal. Finally it communicates with the urinogenital duct that comes out of the kidneys and opens into the cloaca. The cloaca is a small, median chamber that is used to pass faecal matter.
The female reproductive organs include a pair of ovaries (Figure 7.4). The ovaries are situated near kidneys and there ... | 5 | 11 | Biology | 07 |
1ac7083c-09cf-4678-911c-e7dd5e97c9f7 | # PLANT KINGDOM
# 3
# PLANT KINGDOM
# 3.1 Algae
In the previous chapter, we looked at the broad classification of living organisms under the system proposed by Whittaker (1969) wherein he suggested the Five Kingdom classification viz. Monera, Protista, Fungi, Animalia and Plantae. In this chapter, we will deal in d... | 0 | 11 | Biology | 03 |
5bea7c6a-c31d-4d6f-9e93-66a04ed415dd | # BIOLOGY
not only the external features, but also internal features, like ultra-structure, anatomy, embryology and phytochemistry. Such a classification for flowering plants was given by George Bentham and Joseph Dalton Hooker.
At present phylogenetic classification systems based on evolutionary relationships betwee... | 1 | 11 | Biology | 03 |
ef335410-2589-42ea-aa35-c014bff0cefe | # PLANT KINGDOM
# Figure 3.1 Algae
- (a) Green algae
- (i) Volvox
- (ii) Ulothrix
- (b) Brown algae
- (i) Laminaria
- (ii) Fucus
- (iii) Dictyota
- (c) Red algae
- (i) Porphyra
- (ii) Polysiphonia
2024-25 | 2 | 11 | Biology | 03 |
ac0863bf-a0fe-411f-aa31-5ccec128c496 | # BIOLOGY
Algae are useful to man in a variety of ways. At least a half of the total carbon dioxide fixation on earth is carried out by algae through photosynthesis. Being photosynthetic they increase the level of dissolved oxygen in their immediate environment. They are of paramount importance as primary producers of... | 3 | 11 | Biology | 03 |
24b04537-3785-45f5-be86-b2f3add4fe09 | # PLANT KINGDOM
them. Food is stored as complex carbohydrates, which may be in the form of laminarin or mannitol. The vegetative cells have a cellulosic wall usually covered on the outside by a gelatinous coating of algin. The protoplast contains, in addition to plastids, a centrally located vacuole and nucleus. The p... | 4 | 11 | Biology | 03 |
66be98ab-071a-4fe9-bddd-bc2cc502bc1c | # 28
# BIOLOGY
gametes. Sexual reproduction is oogamous and accompanied by complex post fertilisation developments. The common members are: Polysiphonia, Porphyra (Figure 3.1c), Gracilaria and Gelidium.
# 3.2
# BRYOPHYTES
Bryophytes include the various mosses and liverworts that are found commonly growing in moist... | 5 | 11 | Biology | 03 |
77918bd6-3e60-4539-88eb-6aeb162e9047 | # PLANT KINGDOM
Bryophytes are also called amphibians of the plant kingdom because these plants can live in soil but are dependent on water for sexual reproduction. They usually occur in damp, humid and shaded localities. They play an important role in plant succession on bare rocks/soil.
The plant body of bryophytes... | 6 | 11 | Biology | 03 |
a9acccc0-bfbe-4d06-a4d9-3a875ac78873 | # 30
# BIOLOGY
organs are produced either on the same or on different thalli. The sporophyte is differentiated into a foot, seta and capsule. After meiosis, spores are produced within the capsule. These spores germinate to form free-living gametophytes.
# 3.2.2
# Mosses
The predominant stage of the life cycle of a... | 7 | 11 | Biology | 03 |
ba375d0c-b526-4614-b0fd-7028c0c9c26c | # PLANT KINGDOM
# 31
# Strobilus
# Node
# Internode
# Branch
# Rhizome
Figure 3.3 Pteridophytes : (a) Selaginella (b) Equisetum (c) Fern (d) Salvinia
# 2024-25 | 8 | 11 | Biology | 03 |
4e25cc21-31f3-408e-aa7d-05480979bcbd | # 32
# BIOLOGY
Free-living, mostly photosynthetic thalloid gametophytes called prothallus. These gametophytes require cool, damp, shady places to grow. Because of this specific restricted requirement and the need for water for fertilisation, the spread of living pteridophytes is limited and restricted to narrow geogr... | 9 | 11 | Biology | 03 |
4cc5784c-0474-49f3-90c6-66c12c447cbd | # PLANT KINGDOM
The gymnosperms are heterosporous; they produce haploid microspores and megaspores. The two kinds of spores are produced within sporangia that are borne on sporophylls which are arranged spirally along an axis to form lax or compact strobili or cones. The strobili bearing microsporophylls and microspor... | 10 | 11 | Biology | 03 |
26413dee-01ff-41e6-a9ea-09fa649c4148 | # 3.5 ANGIOSPERMS
Unlike the gymnosperms where the ovules are naked, in the angiosperms or flowering plants, the pollen grains and ovules are developed in specialised structures called flowers. In angiosperms, the seeds are enclosed in fruits. The angiosperms are an exceptionally large group of plants occurring in wid... | 11 | 11 | Biology | 03 |
32dbba24-5c9f-4515-9731-75537b5f889f | # PLANT KINGDOM
like structures. The bryophytes are divided into liverworts and mosses. The plant body of liverworts is thalloid and dorsiventral whereas mosses have upright, slender axes bearing spirally arranged leaves. The main plant body of a bryophyte is gamete-producing and is called a gametophyte. It bears the ... | 12 | 11 | Biology | 03 |
8d5b67d1-d7f9-4428-b776-f73e22cd341c | # BIOLOGY
1. Write a note on economic importance of algae and gymnosperms.
2. Both gymnosperms and angiosperms bear seeds, then why are they classified separately?
3. What is heterospory? Briefly comment on its significance. Give two examples.
4. Explain briefly the following terms with suitable examples:
1. protonema... | 13 | 11 | Biology | 03 |
1c94d9a5-821f-41b4-b4bd-4182d3abe5c6 | # CHAPTER 13
# PLANT GROWTH AND DEVELOPMENT
# 13.1 Growth
You have already studied the organisation of a flowering plant in Chapter 5. Have you ever thought about where and how the structures like roots, stems, leaves, flowers, fruits and seeds arise and that too in an orderly sequence? You are, by now, aware of the... | 0 | 11 | Biology | 13 |
453157fc-adba-4fb4-86eb-8d85567f40f8 | # PLANT GROWTH AND DEVELOPMENT
# 13.1 GROWTH
Growth is regarded as one of the most fundamental and conspicuous characteristics of a living being. What is growth? Growth can be defined as an irreversible permanent increase in size of an organ or its parts or even of an individual cell. Generally, growth is accompanied... | 1 | 11 | Biology | 13 |
2db471b7-b054-40b4-9cd8-7e06482fbd59 | # 168
# BIOLOGY
# Shoot apical meristem
The primary growth of the plants and principally contribute to the elongation of the plants along their axis. You also know that in dicotyledonous plants and gymnosperms, the lateral meristems, vascular cambium and cork-cambium appear later in life. These are the meristems tha... | 2 | 11 | Biology | 13 |
c7949c9f-1815-40bf-b3ef-bd9e44e92ce2 | # PLANT GROWTH AND DEVELOPMENT
meristematic zone represent the phase of elongation. Increased vacuolation, cell enlargement and new cell wall deposition are the characteristics of the cells in this phase. Further away from the apex, i.e., more proximal to the phase of elongation, lies the portion of axis which is unde... | 3 | 11 | Biology | 13 |
636f1218-2f7a-487e-993b-99067b95cea3 | # BIOLOGY
The growth rate shows an increase that may be arithmetic or geometrical (Figure 13.4).
In arithmetic growth, following mitotic cell division, only one daughter cell continues to divide while the other differentiates and matures. The simplest expression of arithmetic growth is exemplified by a root elongatin... | 4 | 11 | Biology | 13 |
7101afac-4939-4b6b-b766-3777a1875bd4 | # PLANT GROWTH AND DEVELOPMENT
# Figure 13.7
Diagrammatic comparison of absolute and relative growth rates. Both leaves A and B have increased their area by 5 cm2 in a given time to produce A1, B leaves.
Quantitative comparisons between the growth of living systems can also be made in two ways: (i) measurement and t... | 5 | 11 | Biology | 13 |
028297f4-3ba9-4bff-8845-43972b4b0d48 | # 13.2 DIFFERENTIATION, DEDIFFERENTIATION AND REDIFFERENTIATION
The cells derived from root apical and shoot-apical meristems and cambium differentiate and mature to perform specific functions. This act leading to maturation is termed as differentiation. During differentiation, cells undergo few to major structural ch... | 6 | 11 | Biology | 13 |
dd14393a-318c-42c5-b18d-924fe292564a | # PLANT GROWTH AND DEVELOPMENT
# 173
# Cell Division
# Death
# SENESCENCE
# Plasmatic growth
# Differentiation
# MERISTEMATIC CELL
# MATURE CELL
# Expansion (Elongation)
# Maturation
Figure 13.8 Sequence of the developmental process in a plant cell
Plants follow different pathways in response to environment... | 7 | 11 | Biology | 13 |
e9e6338d-c5bf-4ded-b677-0a65165787c7 | # BIOLOGY
Thus, growth, differentiation and development are very closely related events in the life of a plant. Broadly, development is considered as the sum of growth and differentiation. Development in plants (i.e., both growth and differentiation) is under the control of intrinsic and extrinsic factors. The former ... | 8 | 11 | Biology | 13 |
5caaf39b-3916-41bc-863d-5061dd54a0dc | # PLANT GROWTH AND DEVELOPMENT
The ‘bakanae’ (foolish seedling) disease of rice seedlings, was caused by a fungal pathogen *Gibberella fujikuroi*. E. Kurosawa (1926) reported the appearance of symptoms of the disease in rice seedlings when they were treated with sterile filtrates of the fungus. The active substances w... | 9 | 11 | Biology | 13 |
3ea97bc7-e0e6-431b-be3d-bb1e21d57464 | # BIOLOGY
Auxins also induce parthenocarpy, e.g., in tomatoes. They are widely used as herbicides. 2, 4-D, widely used to kill dicotyledonous weeds, does not affect mature monocotyledonous plants. It is used to prepare weed-free lawns by gardeners. Auxin also controls xylem differentiation and helps in cell division.
... | 10 | 11 | Biology | 13 |
0e3b60e6-1adf-4615-aeb3-b5fffc21fea7 | # PLANT GROWTH AND DEVELOPMENT
synthesised in regions where rapid cell division occurs, for example, root apices, developing shoot buds, young fruits etc. It helps to produce new leaves, chloroplasts in leaves, lateral shoot growth and adventitious shoot formation. Cytokinins help overcome the apical dominance. They p... | 11 | 11 | Biology | 13 |
2c9fb3a2-fe60-46ca-9909-5daeae0b16ba | # BIOLOGY
role in seed development, maturation and dormancy. By inducing dormancy, ABA helps seeds to withstand desiccation and other factors unfavourable for growth. In most situations, ABA acts as an antagonist to GAs.
We may summarise that for any and every phase of growth, differentiation and development of plant... | 12 | 11 | Biology | 13 |
53d59700-c0fa-4eba-ad6b-cad83ff93907 | # PLANT GROWTH AND DEVELOPMENT
Plant growth and development are under the control of both intrinsic and extrinsic factors. Intercellular intrinsic factors are the chemical substances, called plant growth regulators (PGR). There are diverse groups of PGRs in plants, principally belonging to five groups: auxins, gibbere... | 13 | 11 | Biology | 13 |
fa0e6602-36e1-41df-95aa-c60c29bfabc1 | # BIOLOGY
# 10.
What would be expected to happen if:
- (a) GA is applied to rice seedlings
- (b) dividing cells stop differentiating
- (c) a rotten fruit gets mixed with unripe fruits
- (d) you forget to add cytokinin to the culture medium.
2024-25 | 14 | 11 | Biology | 13 |
b4ced422-6100-4388-8af8-a6710b2f4ee2 | # UNIT 1
# DIVERSITY IN THE LIVING WORLD
# Chapter 1
The Living World
# Chapter 2
Biological Classification
# Chapter 3
Plant Kingdom
# Chapter 4
Animal Kingdom
Biology is the science of life forms and living processes. The living world comprises an amazing diversity of living organisms. Early man could easil... | 0 | 11 | Biology | 01 |
85d85597-58d1-43c9-b0bb-ec172904746f | # Ernst Mayr
# (1904 – 2004)
Born on 5 July 1904, in Kempten, Germany, Ernst Mayr, the Harvard University evolutionary biologist who has been called ‘The Darwin of the 20th century’, was one of the 100 greatest scientists of all time. Mayr joined Harvard’s Faculty of Arts and Sciences in 1953 and retired in 1975, ass... | 1 | 11 | Biology | 01 |
1957f02b-5a96-443d-ab90-ec6b3878598e | # CHAPTER 1
# THE LIVING WORLD
# 1.1 Diversity in the Living World
How wonderful is the living world! The wide range of living types is amazing. The extraordinary habitats in which we find living organisms, be it cold mountains, deciduous forests, oceans, fresh water lakes, deserts or hot springs, leave us speechles... | 2 | 11 | Biology | 01 |
69e897e8-5bc4-4c83-9f35-5186df92a2e8 | # 4 BIOLOGY
types of organisms present on earth. We should remember here that as we explore new areas, and even old ones, new organisms are continuously being identified.
As stated earlier, there are millions of plants and animals in the world; we know the plants and animals in our own area by their local names. Thes... | 3 | 11 | Biology | 01 |
22f619f9-8c8a-49a7-9562-b06af96f0e5f | # THE LIVING WORLD
# 4.
The first word denoting the genus starts with a capital letter while the specific epithet starts with a small letter. It can be illustrated with the example of Mangifera indica.
Name of the author appears after the specific epithet, i.e., at the end of the biological name and is written in an... | 4 | 11 | Biology | 01 |
85dbbd1b-24d0-4722-b991-652071031ad0 | # BIOLOGY
used Systema Naturae as the title of his publication. The scope of systematics was later enlarged to include identification, nomenclature and classification. Systematics takes into account evolutionary relationships between organisms.
# 1.2 TAXONOMIC CATEGORIES
Classification is not a single step process b... | 5 | 11 | Biology | 01 |
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Science Class 11 Textbook dataset
The dataset titled science-class11-textbook contains the chapter contents of the Science textbooks for Class 11.
It includes chapters for both Physics and Chemistry.
The chapters in Part 1 are numbered as follows: Chapter 1 is marked as 101, Chapter 2 as 102, and so on. The chapters in Part 2 are numbered starting from 201, 202, and so forth.
Usage
- Use the
datasetslibrary to load the dataset. Install using the following.
pip install datasets
- Load the dataset.
from datasets import load_dataset
dataset = load_dataset("dmedhi/science-class11-textbook")
Contribution
Please leave a ♥ if you've used the dataset.
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