Viruses are sub-microscopic, infectious, nucleoprotein particles that can infect all living organisms. A virus consists of genetic material either in the form of RNA or DNA surrounded by a protein coat.

Most of the viruses, infecting plants, have single-stranded RNA as genetic material. On the other hand, the viruses infecting animals have single or double-stranded RNA or double-stranded DNA.

Bacteriophages or viruses infecting bacteria mostly have double- stranded DNA. Their protein coat called as capsid is made up of capsomere subunits. These capsomeres are arranged in helical or polyhedral geometric forms.

AIDS, smallpox, mumps, and influenza are some common examples of viral diseases.

Reverse osmosis occurs when water is moved across the membrane against the concentration gradient, from lower concentration to higher concentration. Reverse osmosis is an active process.  Osmosis is the process in which water molecules move from a region of higher water potential to a region of lower potential down a water potential gradient across a partially permeable membrane, so little energy is required to carry out this process, thus it is a form or passive transport.

The dental formula represents the arrangement of teeth in each half of the upper and the lower jaw. The entire formula is multiplied by two to represent the total number of teeth.

The dental formula for milk teeth in humans is:

Each half of the upper jaw and the lower jaw has 2 incisors, 1 canine, and 2 molars. Premolars are absent in milk teeth  hence the zero.

The dental formula for permanent teeth in humans is: 

Each half of the upper jaw and the lower jaw has 2 incisors, 1 canine, 2 premolars, and 3 molars. An adult human has 32 permanent teeth.

The pharynx is a five-inch long tube that starts near our nose and ends at our windpipe.

The human pharynx is conventionally divided into three sections: the nasopharynx, oropharynx, and laryngopharynx. It is also important in vocalization.

• 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.

One cannot distinguish whether a plant is C3 or C4 by observing its leaves and other morphological features externally. Unlike C3plants, the leaves of C4 plants have a special anatomy called Kranz anatomy and this difference can only be observed at the cellular level. For example, although wheat and maize are grasses, wheat is a C3 plant, while maize is a C4 plant.

Viruses are non-living features intermediate between non-living and living organisms. On the basis of characters, such as non-cellular organization, inactivity outside the host organism, lack of respiration and cellular metabolism, these are caused non-living. Moreover, similar to non-living objects viruses can be crystallized and precipitated. Living Feature Similar to living beings, they possess genetic material (DNA or RNA), property of mutation, irritability, can grow and multiply inside the host cell. They are intracellular obligate parasites and attack specific hosts. Thus, keeping these points in mind, it is quite difficult to ascertain whether viruses are living or non-living.

A particular level of hierarchy in the classification of living beings is called as a taxon. A taxon is a group of one or more populations of an organism or organisms seen by taxonomists to form a unit. For example, the basic level of classification is species, followed by genus, family, order, class, phylum or division, in ascending order. The highest level of classification is known as a kingdom. So each of these categories can be called as a taxon.

ADH-  Anti-diuretic Hormone

ADH, also known as arginine vasopressin, is a hormone produced by the hypothalamus and stored in the posterior pituitary gland. It is made up of special nerve cells found at the base of the hypothalamus. The hormone is transported to the pituitary gland via axons, where it is released into the bloodstream. It regulates and balances the amount of water in the blood.

Functions Of ADH

• It acts on the kidneys and the blood vessels and functions to control the blood pressure. Higher concentrations of ADH constrict the blood vessels which increases the blood pressure.
• It allows the water in the urine to be taken back in a specific area in the kidney and thus reduces the amount of water excreted through the urine thereby conserving the volume of the fluid in the body.
• It is mainly responsible for homeostasis.

The digestive system consists of an alimentary canal and digestive glands. The alimentary canal of cockroach is divided into foregut, midgut, and hindgut. the foregut opens into a gap, where undigested food is temporarily stored. the mouth opens into a short tubular pharynx, leading to a narrow tubular passage, the esophagus. The gastric sacks contain bacteria that the cockroach uses to digest its food.

Pleura is a structure that covers up the lungs. It has two layers which is been separated by the pleura cavity. Pleura cavity is also called a pleura space, which is mainly the thin and fluid-filled space present between the two pulmonary pleura. Mainly the visceral pleura receives all its blood supply from the bronchial circulation, which is also a supplier of the lungs. The visceral pleura which is responsible for covering the lungs receives the innervations from the autonomic nervous system.

SP = Rs 5225
Let MP be x
discount = 5% of x
              =(5/100)x = 0.05x
SP = MP - discount
⇒5225 = x - 0.05x
⇒0.95x = 5225
⇒x = 5225/0.95 = 5500
∴MP = Rs 5500

There are fundamentally two types of polysaccharides:

• Homo-polysaccharides- These are those which are made up of one kind of monosaccharide elements such as glycogen, starch etc
• Hetero-polysaccharides- These are those which are made up of two or more kind of monosaccharides elements such as hyaluronic acid etc.

Chemotaxonomy is the identification and classification of organisms based on similarities and differences in biochemical composition. Cytotaxonomy can also be defined as the classification of organisms based on differences at the biochemical level especially in the amino acid sequences of common protein.

• Organ system level of organization 
• Bilaterally symmetrical 
• Triploblastic 
• Segmented body 
• Body is divisible into head,thorax and abdomen 
• Jointed appendages 
• Respiratory organs- gills,book gills,book lungs or tracheal systems 
• Circulatory system- open 
• Body cavity- haemocoel

Phases of Cell cycle

Human cell divides once in approximately 24 hours, which may vary in different organisms. In yeasts it takes about 90 minutes to complete the cell division process.

Cell cycle is divided into two basic phases-

1. Interphase– it is the phase between two successive M phases. Interphase lasts for 95% of a cell cycle. This phase is called as resting phase but during this period the cells prepare itself for nuclear division by cell growth.
2. M Phase– when the actual cell division or mitosis occurs. It starts with karyokinesis (nuclear division) or duplication of chromosome and end with cytokinesis or division of cell matrix (cytoplasm division).The interphase is divided into three further phases:

• G1 phase represents the interval between mitosis and initiation of DNA replication. Cell is continuously active and grows in size.

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<a href="https://mycbseguide.com/blog/cell-cycle-cell-division-class-11-notes-biology/#:~:text=CBSE%20Class%2D11%20Biology,cells%20is%20called%20cell%20cycle." ping="/url?sa=t&source=web&rct=j&url=https://mycbseguide.com/blog/cell-cycle-cell-division-class-11-notes-biology/%23:~:text%3DCBSE%2520Class%252D11%2520Biology,cells%2520is%2520called%2520cell%2520cycle.&ved=2ahUKEwjlpYry46ztAhUVxzgGHYoDA2UQFjAGegQIBBAC" rel="noopener" target="_blank">Cell Cycle and Cell Division class 11 Notes Biology ...</a>

Right before prophase, the cell spends most of its life in the interphase, where preparations are made before the beginning of mitosis (the DNA is copied). However, since the actual process involves the division of the nucleus, prophase is technically the first stage of this process.

The different stages of mitosis occurring during cell division are given as follows-

Interphase

Before entering mitosis, a cell spends a period of its growth under interphase. It undergoes the following phases when in interphase:

• G1 Phase: This is the period before the synthesis of DNA.
• S Phase: This is the phase during which DNA synthesis takes place.
• G2 Phase: This is the phase between the end of DNA synthesis and the beginning of prophase.

A n s w e r 
The sequence of events by which a cell duplicates its genome, synthesizes the other constituents of cells and eventually divides into two daughter cells is called cell cycle.

The body movements in humans are of the following types:

• Flexion
• Lateral Flexion
• Dorsiflexion
• Plantarflexion
• Extension
• Hyperextension
• Abduction
• Adduction
• Transverse Abduction
• Transverse Adduction
• RotationLateral Rotation
• Medial Rotation
• Supination
• PronationProtraction
• Retraction
• Elevation
• Depression
• Reversion
• Eversion
• Opposition

A nerve impulse is transmitted from one neuron to another through junctions called synapses. A synapse is formed by the membranes of a pre-synaptic neuron, which may or may not be separated by a gap called synaptic cleft. There are two types of synapses, namely, electrical synapses and chemical synapses. At a chemical synapse, the membranes of the pre-post synaptic neurons are separated by a fluid-filled space called synaptic cleft. Chemicals called neurotransmitters are involved in the transmission of impulses at these synapses. The axon terminals contain vesicles filled with these neurotransmitters. When an impulse (action potential) arrives at the axon terminal, it stimulates the movement of the synaptic vesicles towards the membrane where they fuse with the plasma membrane and release their neurotransmitters in the synaptic cleft. The releases neurotransmitters bind to their specific receptors, present on the post-synaptic membrane. This binding opens ion channels allowing the entry of ions which can generate a new potential in the postsynaptic neuron.

Some characteristic features of Euglenoids are as follows.

• Euglenoids (such as Euglena) are unicellular protists commonly found in fresh water.

• Instead of cell wall, a protein-rich cell membrane known as pellicle is present.

• They bear two flagella on the anterior end of the body.

• A small light sensitive eye spot is present.

• They contain photosynthetic pigments such as chlorophyll and can thus prepare their own food. However, in absence of light, they behave similar to heterotrophs by capturing other small aquatic organisms.

• They have both plant and animal-like features, which makes them difficult to classify and hence they are called as connecting link between plants and animals.

Algae reproduce asexually by a variety of spores such as ,

1) Zoospores : these are flagelated , often with an eyespot. Normally these are formed under favourable conditions e.g. Chlamydomonas.
In Vaucheria, compound zoospores called synzoospore are formed.

2) Aplanospores : these are non motile thin walled zoospores , formed by cleavage of protoplasts within a cell. They are formed under unfavourable conditions e.g. Ulothrix

3) Akinetes : these are formed under unfavourable conditions as method of perinnation. They are thick walled and non motile. On release they form new thalli e.g. Anabaena

4) Hypnospores: these are thick walled aplanospores and are formed during unfavourable conditions. Under prolonged unfavourable conditions the protoplasm of Hypnospores divides to make cysts e.g. Chlamydomonas nivalis.

5) Tetraspores : these are haploid thin walled non motile spores formed after reduction division in diploid tetrasporangia e.g. members of Rhodophyceae and Phaeophceae.

6) Autospores : these are similar to the parent cell. In Chlorella and Scenedesmus autospores acquire all characteristics of parent cells before their discharge from sporangium.

Diatoms are the main producers in marine environment. So, they are also known as the 'pearls of ocean'. As walls of diatoms are made of silica, they do left behind a large amount of cell deposits in their habitat. This accumulation is called diatomaceous earth. Diatomaceous earth is gritty in nature and hence is used for polishing and, in filtration of oils and syrups.

Kingdom Monera includes living organisms that are single celled, such as bacteria. They neither have a nucleus nor cell membrane. The organisms that are included in this kingdom are prokaryotes. Kingdom Monera is divided into two groups i.e. archaebacteria and eubacteria.