Tag: structure and functions of living organisms -ii

Questions Related to structure and functions of living organisms -ii

A diastema :

evs structure and functions of living organisms -ii experiments on digestive enzymes role of receptors in the mouth types of teeth introduction to human digestive system circulatory system and organs

  1. Is a gap between two teeth

  2. Appears due to the absence of canine teeth in herbivores

  3. May occur in humans

  4. Is related to more than one option given above

Show answer
Correct Option: D
Explanation:

A diastema is a gap between teeth mostly seen in the front teeth. It mainly occurs in mammals mostly in humans. It is caused by missing of teeth or undersized teeth.

So, the correct option is 'Is related to more than one option given above'

Permanent teeth start their appearance in children at the age of ......... years.

evs structure and functions of living organisms -ii experiments on digestive enzymes role of receptors in the mouth types of teeth introduction to human digestive system circulatory system and organs

  1. 4

  2. 6

  3. 10

  4. 12

Show answer
Correct Option: B
Explanation:

The arrival of second teeth occurs at 6 years +/- 6 months. With the exception of the wisdom teeth, the last of the secondary teeth come in around 12 years of age. 

Carnassial teeth are modified for

evs structure and functions of living organisms -ii experiments on digestive enzymes role of receptors in the mouth types of teeth introduction to human digestive system circulatory system and organs

  1. Crushing

  2. Tearing

  3. Grinding

  4. Cutting

Show answer
Correct Option: B
Explanation:

Carnassial teeth are the molar and premolar teeth modified for shearing flesh by having cusps with sharp cutting edges. They are typical of animals of the order carnivora (e.g., tigers, wolves), in which they are the first molars in the lower jaw and the last premolars in the upper.

Man bears $4$ kinds of teeth from front to the back of the jaw. Choose the correct order from the following.

evs structure and functions of living organisms -ii experiments on digestive enzymes role of receptors in the mouth types of teeth introduction to human digestive system circulatory system and organs

  1. (i)- Incisor, (ii)- Canine, (iii)- Premolars, (iv)- Molars

  2. (i)- Molars, (ii)- Canine, (iii)- Premolars, (iv)- Incisor

  3. (i)- Molars, (ii-) Canine, (iii)- Incisor, (iv)- Premolars

  4. (i)- Incisor, (ii)- Premolars, (iii)- Molars, (iv)- Incisor

Show answer
Correct Option: A
Explanation:

Incisors are the most anterior teeth. Canines - all mammals have a single canine in each quadrant. The premolars lie immediately posterior to the canines. In the upper jaw, they are found in the maxillary. The most posterior teeth in the jaws of most mammals are molars. Humans have two incisors, one canine, two premolars, and three molars, I2 C1 P2 M3, in each quadrant of their upper jaws. The numbers for each quadrant of the lower jaw are the same, and the general formula is written I2/2 C1/1 P2/2 M3/3. 

Match the following.

1. Incisors a. Grinding teeth
2. Canines b. Cracking teeth
3. Premolars c. Cutting teeth
4. Molars d. Tearing teeth
evs structure and functions of living organisms -ii experiments on digestive enzymes role of receptors in the mouth types of teeth introduction to human digestive system circulatory system and organs

  1. 1 - b, 2 - d, 3 - a, 4 - c

  2. 1 - b, 2 - a, 3 - d, 4 - c

  3. 1 - c, 2 - b, 3 - d, 4 - a

  4. 1 - c, 2 - d , 3 - b , 4 - a

Show answer
Correct Option: D
Explanation:
  • Incisors: The middlemost four teeth on the upper and lower jaws which help in cutting the food. So, they are referred to as cutting teeth.
  • Canines: The pointed teeth just outside the incisors which help in tearing of the food.
  • Premolars: Teeth between the canines and molars which helps in cracking of food.
  • The molars or molar: teeth are large, flat teeth at the back of the mouth. They are used primarily to grind food during chewing. 
So, the correct answer is  D.

A dental disease characterised by mottling of teeth is due to the presence of an ingredient in drinking water, namely

evs structure and functions of living organisms -ii experiments on digestive enzymes role of receptors in the mouth types of teeth introduction to human digestive system circulatory system and organs

  1. Flourine

  2. Mercury

  3. Boron

  4. Chlorine

Show answer
Correct Option: A
Explanation:

Dental fluorosis, also termed as mottled enamel is an extremely common disorder. It is caused by overexposure to fluoride during the first eight years of life. This is the time when most permanent teeth are being formed. Clinical dental fluorosis is characterized by staining and pitting of the teeth. In more severe cases all the enamel may be damaged.. The early symptoms of skeletal fluorosis, include stiffness and pain in the joints.  Hence, the dental disease characterised by mottling of teeth is due to the presence of an ingredient in drinking water is fluorine.

So the correct answer is ''fluorine''

 

 

Teeth that are different in shape, size and function are called as

evs structure and functions of living organisms -ii experiments on digestive enzymes role of receptors in the mouth types of teeth introduction to human digestive system circulatory system and organs

  1. Acrodont

  2. Pleurodont

  3. Homodont

  4. Heterodont

Show answer
Correct Option: D
Explanation:

Heterodont is an animal which possesses more than a single tooth morphology. For example, humans possess incisors, canines (eyeteeth), premolars and molars.

Homodont is an animals whose teeth are all of the same type. Most vertebrates except mammals are homodont. 
Pleurodont is a formation of the teeth that are fused  by their sides to the inner surface of the jaw bones.
Acrodont is a formation of the teeth whereby the teeth are consolidated with the summit of the alveolar ridge of the jaw without sockets. The term also refers to species of reptiles that have such a formation.

Grinding and chewing teeth are called as

evs structure and functions of living organisms -ii experiments on digestive enzymes role of receptors in the mouth types of teeth introduction to human digestive system circulatory system and organs

  1. Premolars

  2. Canines

  3. Incisors

  4. Molars

Show answer
Correct Option: D
Explanation:

Adult human teeth have 12 molars. They are biggest and strongest teeth. The large surface are o molars helps in grinding and chewing the food. They break up the food into pieces small enough for making it easy to swallow.

So, the correct answer is "Molars".

Layer of cells that secrete enamel of tooth is 

evs structure and functions of living organisms -ii experiments on digestive enzymes role of receptors in the mouth types of teeth introduction to human digestive system circulatory system and organs

  1. Osteoblast

  2. Ameloblast

  3. Odontoblast

  4. Dentoblast

Show answer
Correct Option: B
Explanation:

Osteoblast-bone forming cell. Ameloblast-enamel elaborating cell. Odontoblast- dentine elaborating cell. Dentoblast- tooth cell.

The teeth placed at the end of the buccal cavity and help in chewing food are which of the following?

evs structure and functions of living organisms -ii experiments on digestive enzymes role of receptors in the mouth types of teeth introduction to human digestive system circulatory system and organs

  1. Incisors

  2. Molars

  3. Canines

  4. Premolars

Show answer
Correct Option: B
Explanation:
The most posterior teeth in the mouth are the molars. They have broader and flatter surfaces with 4-5 cusps. They help in chewing and grinding the food.
So the correct answer is 'Molars'.