Homeostasis : The Steady State – 12th Class Biology Q Ans Lesson 18 – NIOS
INTEXT QUESTIONS 18.1
- Define homeostasis.
Ans. Homeostasis is the regulation of a steady internal condition.
- List any three chemicals whose concentration in our body has to be maintainedat partcular levels.
Ans. (i) sugar, (ii) salt, (iii) water
- To obtain enough oxygen for respiration at high altitudes, what does the bodydo?
Ans. The body adds more RBCs to the blood
INTEXT QUESTIONS 18.2
- How do the following temperatures affect the enzymes?
(i) 45°C and above – Denatured
(ii) 0°C and below – Inactive
- (i) At what temperature range do enzymes act best? – 35-40°C
(ii) What technical term do you use for this temperature? – Optimum temperature
INTEXT QUESTIONS 18.3
- Classify the following animals as endotherm or ectotherm :
Camel, Bat, Earthworm, Cockroach, Fish, Wall lizard, Polar bear, sparrow
Endotherms – Camel, Bat, Polar bear, sparrow
Ectotherms – Earthworm, Cockroach, Fish, Wall lizard
- Explain the following terms and give one or more synonymous terms for each:
Ans. Poikilotherms : Animals whose body temperature changes along with
that of the surroundings
Warm blooded : Animals whose body temperature remains steady and
does not change with that of the surroundings
- Mention one way each by which each of the following fight severe cold:
Ans. Crocodile : Basks in the sun on the land
Honey bees : Crowd together for collective warmth
Common frog : Hibernates
Wall lizard : Hides at safe places
INTEXT QUESTIONS 18.4
- Rearrange the following in their correct sequence in homeostasis:
Effector, Set point, Integrating centre, Sensor.
Ans. Set point, Sensor, Integrating centre, Effectors
- State in one word or sentence :
(i) The normal body core temperature of humans. – 37°C
(ii) The function of feathers in bird and the hairs of rabbit. – trap air to prevent heat loss
(iii) Effect of shivering. – warms up in cold weather
INTEXT QUESTIONS 18.5
- Name the two kinds of feed back mechanisms.- Negative and positive
- Which kind of feed back mechanism normally operates in homeostasis? – Positive
- List the three conditions necessary for the body cells to function properly.
- When do we pass out more concentrated urine–during hot summers or coldwinters ?
- How does our body deal with any extra sugar absorbed into the blood aftermeals?
- What is our normal RBC count per cubic millimetre? Will it go up or go downif a plain dweller shifts to a mountain or hill?
- In which temperature range do the enzymes in our body act best?
- Name the two terms often used synonymously for ectotherms.
- Name any two animals, which tolerate the intense heat of the deserts bypromoting heat loss.
- Which kind of feedback mechanism–the positive or the negative, normally
operates in bringing about water-salt balance in our body.
- How is the enzymatic activity affected upon cooling?
- How do honeybees fight cold during intense winter?
- Differentiate between the two terms homeotherms and poikilotherms.
- Give any two examples of preventing loss of body heat by postural behaviourin humans.
- List the components of homeostasis in their proper sequence.
- Differentiate between positive and negative feedback mechanism.
- Explain the role of the following in thermoregulation in humans:
(i) Sweat glands
(ii) Skeletal muscles
(iii) Blood vessels in the skin
- What is meant by feed back mechanism? What are its two types? Which oneof these is applicable to thermoregulation and why?
- Why is thermoregulation required in our body?
- Differentiate between endotherms and ectotherms. Which ones of these do youthink can survive better if there is a suden change in environmental temperature?
- Differentiate between physiological and behavioral responses for thermoregulationin humans.
- Explain the role of hypothalamus during heat regulation in humans.
- Explain the relationship between sensor and integrating centre during any one kind of homeostasis.
NIOS 12th class biology Q Ans
- Origin and Evolution of Life & Classification : 12th Class Biology Notes – NIOS
- The Kingdoms Monera, Protista & Fungi : 12th Class Biology Notes – NIOS
- Kingdoms Plantae & Animalia : 12th Class Biology Question Answer Lesson 3 – NIOS
- Cell Structure & Function : 12th Class Biology Question Answer Lesson 4 – NIOS
- Tissues & Others Level of Organization : 12th Class Biology Question Answer Lesson 5 – NIOS
- Root System : 12th Class Biology Question Answer Lesson 6 – NIOS
- Shoot System : 12th Class Biology Question Answer Lesson 7 – NIOS
- Absorption, Transport & Water Loss (Transpiration) in Plants : 12th Class Biology Q Ans Lesson 8 – NIOS
- Nutrition in Plants – Mineral Nutrition : 12th Class Biology Question Answer Lesson 9 – NIOS
- Nitrogen Metabolism : 12th Class Biology Question Answer Lesson 10 – NIOS
- Photosynthesis : 12th Class Biology Question Answer Lesson 11 – NIOS
- Respiration in Plants : 12th Class Biology Question Answer Lesson 12 – NIOS
- Nutrition and Digestion : 12th Class Biology Question Answer Lesson 13 – NIOS
- Respiration and Elimination of Nitrogenous Wastes : 12th Class Biology Q Ans Lesson 14 – NIOS
- Circulation of Body Fluids : 12th Class Biology Question Answer Lesson 15 – NIOS
- Locomotion and Movement : 12th Class Biology Question Answer Lesson 16 – NIOS
- Coordination & Control : The Nervous & Endocrine Systems | 12th Class Biology Q Ans Lesson 17 – NIOS
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