• Schleiden and Schwann together formulated the cell theory.
• Rudolf Virchow (1855) first explained that cells divided and new cells are formed from pre-existing cells.
• Cell theory states that
• All living organisms are composed of cells and products of cells.
• All cells arise from pre-existing cells.

The amount of blood pumped by heart per minute is called cardiac output. It is calculated by multiplying stroke volume (volume of blood pumped by each ventricle per minute) with heart rate (number of beats per minute). The heart of normal person beats 72 times per minute and pumps out about 70 mL of blood per beat. Therefore, cardiac output averages 5000 mL or 5 litres.

Christiaan Neethling Barnard  was a South African cardiac surgeon who performed the world's first highly publicized heart transplant and the first one in which the patient regained consciousness. On 3 December 1967

The coronary arteries provide the main blood supply to the heart. The coronary arteries also supply the myocardium with oxygen to allow for the contraction of the heart and thus causing circulation of the blood throughout the body.

Rubisco stands for Ribulose bisphosphate carboxylase. Rubisco is a carboxylase/oxygenase enzyme which plays a dual role in Calvin cycle. This is because the active site of enzyme is same for both carboxylation and oxygenation reactions.

*Ribulose bisphosphate carboxylase is an enzyme which catalyses the combination of RuBP with carbo dioxide to give rise to two molecules of phosphoglyceric acid (PGA) during Calvin cycle.
*When there is less concentration of Carbon dioxide and high Oxygen concentration, RuBP is oxidised to one molecule of phosphoglycolate and one molecule of PGA during Calvin cycle.

Macromolecules are large complex molecules present in colloidal state in intercellular fluid. They are formed by the condensation of low molecular weight micromolecules and hence are polymeric in nature.

Polysaccharides, proteins, and nucleic acids are common examples of macromolecules.

Biodiversity conservation is the protection and management of biodiversity to obtain resources for sustainable development. Biodiversity conservation has three main objectives: Sustainable utilization of species and ecosystem. To maintain life-supporting systems and essential ecological processes. Biodiversity conservation protects the plant, animal, microbial and genetic resources for food production, agriculture, and ecosystem functions such as fertilizing the soil, recycling nutrients, regulating pests and disease, controlling erosion, and pollinating crops and trees.

There are three amino acids that have basic side chains at neutral pH. ... For these amino acids, the protonated forms predominate at physiological pH (about 7). Two amino acids have acidic side chains at neutral pH. These are aspartic acid or aspartate (Asp) and glutamic acid or glutamate (Glu). Histidine is the most basic amino acid in the given compound. This can be attributed to the fact that the histidine contains the most number of a basic nitrogen atom. Normally, an amino acid produces a nearly neutral solution since the acid group and the basic amine group on the root amino acid neutralize each other in the zwitterion. If the amino acid structure contains two acid groups and one amine group, there is a net acid producing effect.

he main organs of the alimentary canal are:

• The Mouth and Oral cavity.
• Esophagus.: It is a muscular tube through which small bolus of food passes from the mouth to the stomach. It is sharply bent at the point at which it meets the stomach. This prevents the backward movement of food from the stomach into it. Food in the digestive tract moves by an involuntary movement of alternate contraction and relaxation of muscles called peristalsis.
• Stomach:

  It is a muscular bag which has three parts- cardiac part, fundus, and body.

• Cardiac part– It is so called because it is present close to the heart. The opening of the esophagus to the stomach is regulated by the cardiac sphincter.
• Fundus– It is dome-shaped and is usually filled with air.
• Body– This is the main part of the stomach. The opening of the stomach into the small intestine is regulated by the pyloric sphincter.
• Largeintestine.The small intestine leads into the large intestine which has three parts- Caecum, Colon, and Rectum.
• Caecum– It is a small sac-like structure at the point where the small intestine meets the large intestine.
• Colon– It is divided into four regions-  transverse colon,  sigmoid colon ascending colon and descending colon.
• Rectum– It opens into the ****.
• Small intestine.:It is the longest part of the alimentary canal and comprises three parts- Duodenum, Jejunum, and Ileum.
• Duodenum– It is C- shaped and receives the hepatopancreatic duct formed by the union of bile and pancreatic duct.
• Jejunum–  Middle part of small intestine with thick walls and more vasculature.
• Ileum– The lower part of the small intestine with thin walls and less vasculature.

• Mouth

The mouth is the opening through which the intake of food occurs.

• Oral cavity

The oral cavity has three parts –the palate, tongue, and teeth.

Palate -It forms the roof of the oral cavity. The anterior part is called hard palate and the posterior part is called soft palate.

Tongue -Tongue is a muscular and glandular structure attached to the base of the oral cavity. On the upper surface, it has a V-shaped furrow called sulcus terminalis. It divides the tongue into the anterior oral part and posterior pharyngeal part. Its upper surface also consists of tiny projections called lingual papillae. Lingual papillae are of three kinds in humans-

(i)Vallate or circumvallate papillae -have gustatory receptors to sense taste

(ii) Filiform papillae- smallest and contain touch receptors.

(iii) Fungi-form papillae- Rounded and mostly present at the tip of the tongue.

• Teeth

Humans are diphyodont i.e. they have two sets of teeth- milk or deciduous and permanent teeth. Here is the list of different types of teeth in humans with their functions.

The human digestive system consists of the alimentary canal and its associated glands. Food is taken into the body through the mouth.

Digestion in human beings starts in the mouth. The mouth contains teeth, tongue and salivary glands. The teeth cut the food into small pieces, chew and grind it. The tongue mixes the food with saliva. The salivary glands secrete a watery liquid called saliva.

The slightly digested food goes into the food pipe or oesophagus by peristalsis. No digestion of food takes place in the oesophagus.

The slightly digested food reaches the stomach through oesophagus for further digestion where it is broken down into smaller pieces. The inner lining of the stomach secretes gastric juice which includes mucus, hydrochloric acid and digestive juices. Mucus protects the lining of the stomach from hydrochloric acid. Hydrochloric acid makes the medium in the stomach acidic to facilitate the digestion of proteins. The digestive juices break down the protein into simpler substances. Then the partially digested food goes into the small intestine.

The small intestine is a very long and narrow tube where complete digestion of food takes place. It receives secretions of liver, pancreas and its own walls. Liver secretes liquid called bile which helps in the digestion of fats and converts them into small droplets. Pancreas secretes pancreatic juice which breaks down fats into fatty acids and glycerol. Pancreatic juice also breaks down carbohydrates and proteins into simpler forms. The intestinal juice secreted by the walls of small intestine breaks down the carbohydrates into glucose, proteins into amino acids. Thus, the food gets completely digested in small intestine.

Absorption: The digested food material passes into the blood vessels in the walls of small intestine. This process is called absorption. The inner walls of small intestine have millions of tiny, finger-like outgrowths called villi which increase the surface area for rapid absorption of digested food. Each villus has a network of blood vessels which absorbs the digested food materials into the blood flowing through them.

Assimilation: The blood carries the absorbed food materials to the cells in all the parts of the body where it is used for growth, energy and repair. This is called assimilation. Glucose breaks down utilizing oxygen to form carbon dioxide and water, and releases energy.

The undigested and unabsorbed food passes from the small intestine into large intestine. Most of the water is absorbed from the undigested food materials in the large intestine.

Egestion: The undigested food is temporarily stored in the last part of the large intestine called rectum and finally the semi-solid waste is passed out from the body through **** in the form of faeces. This is called egestion.

Teeth: Teeth break down the food into smaller pieces. There are four types of teeth in our mouth. They are:

1. Incisors: These are chisel shaped teeth at the front of the mouth and used for biting and cutting the food.
2. Canines: These are large and pointed teeth just behind the incisors and are used for piercing and tearing the food. 
3. Premolars: These are large teeth just behind the canines on each side and are used for chewing and grinding the food.
4. Molars: These are very large teeth present just behind the premolars and help for chewing and grinding the food.

• The human digestive system consists of the alimentary canal and the associated glands.

Alimentary canal 

• The alimentary canal begins with an anterior opening – the mouth, and it opens out posteriorly through the ****.
• The mouth leads to the buccal cavity or oral cavity, which has a number of teeth and a muscular tongue and each tooth is embedded in a socket of jaw bone with a type of attachment called as thecodont.
• A set of temporary milk or deciduous teeth is replaced by a set of permanent or adult teeth, and the type of dentition is called diphyodont.
• An adult human has 32 permanent teeth, which are of four different types
• incisors (I)
• canine (C)
• premolars (PM)
• and molars (M).
• Arrangement of teeth in each half of the upper and lower jaw in the order I, C, PM, M is represented by a dental formula which in human is 2123/2123.
• The tongue is a freely movable muscular organ attached to the floor of the oral cavity by the frenulum, and the upper surface of the tongue has small projections called papillae, some of which bear taste buds.
• The oesophagus and the trachea open into the pharynx.
• A cartilaginous flap called epiglottis prevents the entry of food into the glottis, which is the opening of the wind pipe.
• The oesophagus is a thin, long tube which extends posteriorly passing through the neck, thorax and diaphragm and leads to a ‘J’ shaped bag like structure called stomach.
• The stomach has three major parts
• a cardiac portion into which the oesophagus opens
• a fundic region
• a pyloric portion which opens into the first part of small intestine.
• Small intestine is distinguishable into three regions
• a ‘U’ shaped duodenum
• a long coiled middle portion jejunum
• a highly coiled ileum.
• The opening of the stomach into the duodenum is guarded by the pyloric sphincter.
• Ileum consists of
• caecum
• colon
•  
• Caecum is a small blind sac from which a vestigial organ called vermiform appendix
• The colon is divided into three parts
• an ascending
• a transverse
• a descending part.
• The descending part opens into the rectum which opens out through the ****.
• The wall of alimentary canal from oesophagus to rectum possesses four layers
• Serosa
• muscularis
• sub-mucosa
•  
• Serosa is the outermost layer and is made up of a thin mesothelium and some connective tissues.
• Muscularis is formed by smooth muscles usually arranged into an inner circular and an outer longitudinal layer.
• The submucosal layer is formed of loose connective tissues.
• Mucosa is the innermost layer which forms rugae in the stomach and small finger-like foldings called villi in the small intestine.
• The cells lining the villi produce numerous microscopic projections called microvilli giving a brush border appearance.
• Villi are supplied with a network of capillaries and a large lymph vessel called the lacteal.
• Mucosal epithelium has goblet cells which secrete mucus that help in lubrication.
• Mucosa forms gastric glands in the stomach crypts of Lieberkuhn in different parts of the alimentary canal.