Plus 2 Level - Biology Coaching Classes & Tuition Centers in Guwahati

It is called the pharynx (behind the nose and mouth) which connects them to the oesophagus and larynx.

Synapses

Dr. George Gey in 1951

Lysosomes are called suicidal bags because it can digest the cell in which it is present. They are membranous organelles which are present inside the cell and contain digestive hydrolytic enzymes. These enzymes help in breaking down cellular components, or cellular debris as well as foreign material. When they break down the cell in which they are present it is called autolysis. This causes cell death and therefore the name suicidal bags.

In xerophytes (plants which grow in dry conditions), stomata are located on the lower (abaxial) surface of the leaves which is a cooler side compared to the upper (adaxial) surface which faces the sun. Stomata in such plants are further protected from the desiccating outer air by their location being present in stomatal crypts. In day time their stomata is closed. In hydrophytes (plants which live in moist environments and partially/fully submerged in water) stomata are mostly open as they do not have the requirement for saving water in comparison to terrestrial plants.

Antheridophore is the modified portion of the thallus.

It has a flat surface having an antheridial opening.

This helps in sperm dispersal.

Each of the chamber present on the upper surface of the antheridiophore, has an antheridium.

The ventral surface contains rhizoids and scales.

Answer - Bile

Bile is a fluid which is made as well as released by liver.

It is stored in gall bladder.

Bile helps in digestion by breaking down fats into fatty acids.

Saliva is  a thick, colourless fluid which is present in the mouth of humans as well as other vertebrates. The composition of saliva is:

1. Water

2. Mucus

3. Proteins

4. Mineral salts

5. Amylase

Trypsin is an enzyme that helps in digestion of proteins. It is found in small intestine. 

Pepsin is an enzyme produced in  stomach which helps in digesting proteins.

The enzyme is secreted by gastric chief cells as an inactive zymogen called pepsinogen.

Parietal cells present in the stomach lining release hydrochloric acid. The acid  lowers the pH of the stomach to a level of 1.5 to 2 which in turn activates pepsin.

Vertebrates are animals which have a vertebral column or a notochord at any point in their lives.

They  are classified into 7 classes based on their anatomical and physiological features:

1. Mammals (Class Mammalia) - They  have the ability to regulate their body temperature irrespective of the surrounding temperature. Thus they are endothermic. Example - humans and platypuses.

2. Birds (Class Aves) - they are characterised by feathers, toothless beaks and a higher metabolic rate. They lay hard-shelled eggs. example - Crow, Pigeon

3. Reptiles (Class Reptilia) - Examples in this class are snakes, crocodiles and turtles. Characteristically they are ectothermic.

4. Amphibians (Class Amphibia) - Examples in this class are frogs toads and salamanders. They are ectothermic. Both reptiles and amphibians are considered tetrapods, but the distinguishing feature between them is their breeding behaviour. Amphibians need water to breed and their eggs are shell-less. They also undergo metamorphosis where the young ones change from aquatic larval form (having gills and fins) to terrestrial adult form.

5. Bony fishes (Class Osteichthyes) - They are characterized by their bony skeleton. They are the largest class of vertebrates . example - Siamese fighting fish

6. Cartilaginous fishes (Class Chondrichthyes) - They have cartilaginous skeleton. Example - sharks, rays, skates and sawfish. 

5. Jawless fishes (Class Agnatha) - They are primitive fishes having a jawless, circular mouth  which help in holding and feeding on other fishes. They are mostly parasites and scavengers. Example - hagfish

Volant adaptations are the adaptations in  animals which are capable of flying.

As atmospheric environment is characteristically lighter than any of the other habitats like aquatic or terrestrial, there is less friction from air to the organism which is flying,mainly birds. 

Volant adaptations are usually adaptations which help them in flying like:

1. Body covered with feathers.

2. Light and fused bones

These adaptations help them to propel their body during flight.

Ova and sperm aalso referred to as sex cells. Female gametes are called ova or egg cells, and male gametes are called sperm. Gametes are haploid cells, and each cell carries only one copy of each chromosome. These reproductive cells are produced through a type of cell division called meiosis. Masturbation is stimulating the genitals of male or female for orgasm or pleasure