Class 10 Science Respiration Exam Notes

Class 10 Science Respiration Exam Notes. Please refer to the examination notes which you can use for preparing and revising for exams. These notes will help you to revise the concepts quickly and get good marks.

Respiration

It is a biochemical process of enzyme including oxidative breakdown of organic compounds inside living cells releasing energy in the form of ATP.

Breathing

The process of intaking O₂ & releasing of CO₂ known as breathing .

Respiration In Plants

By young roots  :

Air occurs in soil interspaces. Root hairs as well as epiblema cells of the young roots are in contact with them. They are also permeable to metabolic gases. Oxygen of the soil air diffuses through root hair-epiblema cells and reaches all internal cells of the young root. Carbon dioxide produced by root cells diffuses in the opposite direction.

By Leaves :

• Leaves and Young Stems. Leaves and young stems are ideally suited to quick exchange of gases. The organs have a covering of nearly impermeable epidermis for reducing loss of water. The epidermis of leaves bears a number of aerating pores called stomata (singular stoma or stomata, Gk. stoma-mouth). Each aerating or stomatal pore is bordered a pair of guard cells. In most of the plants, the guard cells are kidney or bean shaped with inner walls being thicker and less elastic than the outer walls.

• When the stomata are open, gases diffuse into and out of the leaf as per their concentration gradient. A gas which has come from outside first reaches substomatal chambers. From here, it diffuses to all the intercellular air spaces present in between the mesophyll cells. If the stomata are open during night, oxygen from outside will diffuse into the leaves and young stems while carbon dioxide will diffuse out. It is due to respiratory gas exchange.

 MAMMALIAN RESPIRATORY SYSTEM

The mammalian respiratory system consists of nasal cavity, pharynx, larynx, trachea, bronchi, bronchioles and alveoli.

 Nostril :

•  It is also called external nares.

 Nasal Chamber :

• Nasal septum divides nasal cavity into two nasal chamber by the nasal septum.

 Internal nares :

• There are posterior opening of nasal chambers that leads into pharynx.

 Pharynx 

• The pharynx provides passage to both air and food.

 Laryngopharynx :

• It is the lower part of pharynx and has a slit like aperature called glottis, which can be closed by a leaf like bilobed cartilage epiglottis, during swallowing of food bolus.

 Larynx :

• It is also called voice box or adam's apple or pomas adami.

 Vocal cord :

In larynx, 2 pairs of vocal cord is found outer pair is false vocal cord whereas, inner pair is true vocal cord when air is forced through the larynx it cause vibration of true vocal cords and sound is produced.

 Trachea (Wind pipe) :

• It is long, tubular structure which runs downward through the neck in front of oesophagus. It is supported by cartilage to prevent collapse.

 Primary bronchi :

•  These are one pair of small thin walled tubular structure formed by the division of trachea. It further divides and end at alveoli.

 Lungs :

• lungs are present in thoracic cavity on either side of heart. covered by pleural membrane.

 MECHANISM OF RESPIRATION

Respiratory centre is in Medulla Oblongeta.

Mechanism of breathing involves Two Phases. (A) Inspiration

(B) Expiration

 Inspiration :

• Intercostal and phrenic muscles of diaphragm contract to increase thoracic cavity, therefore outside rushes inside.

 Expiration :

• Intercostal & phrenic relex muscles.

• Due to decrease of thoracic cavity air pressure within lungs increase, the greater pressure within lungs force ful air from lungs to outside of body.

 Gaseous Exchange :

• Gaseous exchange occur in Alveoli following pressure gradient O₂ from high pressure in alveoli diffuse into blood & CO₂ from blood in alveoli.

 Gaseous Transport :

• O₂ is carried by haemoglobin (in RBC). 100 ml of blood can carry ~20 ml of O₂ max, CO₂ is transported in form of bicarbonates in plasma.
   

Question. The process of respiration is not concerned with
(A) liberation of oxygen
(B) liberation of carbon dioxide
(C) liberation of energy
(D) intake of oxygen
Answer : A

Question. Respiration in yeast
(A) takes place in the presence of oxygen
(B) yields lactic acid and carbon dioxide
(C) is anaerobic and produces carbon dioxide
(D) takes place only in darkness
Answer : C

Question. Leaves respire with the help of
(A) lenticels
(B) stomata
(C) plasmodesmata
(D) cuticle
Answer : B

Question. The common immediate source of energy for cellular activity is
(A) NAD
(B) ATP
(C) DNA
(D) RNA
Answer : B

Question. Muscle cells engaged in vigorous activity build up a high concentration of
(A) lactic acid
(B) pyruvic acid
(C) alcohol
(D) cholesterol
Answer : A

Question. More energy production occurs in which respiration –
(A) aerobic respiration
(B) anaerobic respiration
(C) same energy in both
(D) energy production is uncertain
Answer : A

Question. In man, which of the following structures is used for gaseous exchange ?
(A) Nostrils
(B) Lungs
(C) Bronchioles
(D) Alveoli
Answer : D

Question. Correct statement is
(A) roots of plant respire through lenticels and stomata
(B) stem of plant respire through lenticels
(C) both A and B are correct
(D) both A and B are incorrect
Answer : B

Question. Breathing rate in mammals is controlled by part of the brain called the
(A) thalamus
(B) hypothalamus
(C) medulla oblongata
(D) cerebellum
Answer : C

Question. The tissue respiration refers to
(A) inspiration
(B) external respiration
(C) internal respiration
(D) expiration
Answer : C

Question. Which of the following prevents collapsing of trachea ?
(A) Diaphragm
(B) Ribs
(C) Cartilaginous ring
(D) Muscles
Answer : C

Question. Which of the following is not a characteristic of good respiratory surface ?
(A) Thin and moist
(B) Large surface area
(C) Close to oxygen and gas transport
(D) Thick and dry surface
Answer : D

Question. Pneumatophores take part in
(A) excretion
(B) feeding
(C) respiration
(D) reproduction.
Answer : C

Question. Which is the correct sequence of the air passage in man ?
(A) nasal cavity → pharynx larynx → trachea → bronchi → bronchioles → alveoli sac
(B) nasal cavity → pharynx → trachea → larynx → bronchi → bronchioles → alveoli
(C) nasal cavity → larynx → bronchi → pharynx → trachea → bronchioles → alveoli
(D) nasal cavity → larynx → pharynx → trachea → bronchi → bronchioles → alveoli
Answer : A

Question. Vocal cords occur in which structure ?
(A) pharynx
(B) glottis
(C) bronchial tube
(D) larynx
Answer : D

Question. If the CO₂ concentration in the blood increases, the rate of breathing will
(A) decrease
(B) stop
(C) increase
(D) have no effect
Answer : C

Question. Disease called pleurisy is due to
(A) inflammation of pleura
(B) inflammation of trachea
(C) inflammation of alveoli
(D) none of the above
Answer : A

Question. Which of the following gases makes the most stable combination with the haemoglobin of red blood cells ?
(A) CO₂
(B) CO
(C) O₂
(D) N₂
Answer : B

Question. Most of the carbon dioxide in the blood is carried in the form of
(A) carbonic acid
(B) bicarbonates
(C) carbaminohaemoglobin
(D) dissolved CO₂
Answer : B

Question. In respiration pyruvic acid is :
(A) Broken down into two carbon fragment and carbon dioxide
(B) Formed only when oxygen is available
(C) One of the products of Kreb’s cycle
(D) A result of protein break down
Answer : A

Question. Rate of respiration is directly affected by :
(A) Concentration of CO₂
(B) Oxygen in trachea
(C) Concentration of O₂
(D) Diaphragm expansion
Answer : A

Question. Lenticels are found in :
(A) The woody stem for gaseous exchange.
(B) The root where primary growth has occurred.
(C) The roots as well as stem where secondary growth has occurred for photosynthesis
(D) None of the above
Answer : A

Question. In a plant organ which is covered by periderm and in which the stomata are absent, some gaseous exchange still takes place through
(A) aerenchyma
(B) trichomes
(C) pneumatophores
(D) lenticels.
Answer : D

Question. Oxygen is transported in blood mainly by
(A) leucocytes
(B) erythrocytes
(C) thrombocytes
(D) blood plasma
Answer : B

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