Organisation Of Life Book Back Questions 8th Science Lesson 18
8th Science Lesson 18
18] Organisation Of Life
Book Back Questions with Answer and Do You Know Box Content
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Our body is developed from a single cell called zygote. The zygote undergoes continuous mitotic division and forms the foetus consisting multitude of cells of different shape, size and content. Foetal cells gradually attain change in structure and function. This process is known as cell differentiation.
On an average, an adult human being at rest breathes in an out 15-18 times in a minute. During heavy exercise, breathing rate can increase upto 25 times per minute.
Smoking damages lungs. Smoking is also linked to cancer. It must be avoided. When you sneeze, you should cover nose so that the foreign particles you expel are not inhaled by others.
The mixing of foodstuffs and digestive juices in the gut occurs by diffusion. Exchange of respiratory gases (oxygen and carbon dioxide) between blood and tissue fluids between tissue fluid and cells also occurs by diffusion.
Aerobic respiration releases 19 times more energy than anaerobic respiration from the same amount of glucose. In aerobic respiration each glucose molecules produce 36 ATPs.
Basal metabolism refers to the minimum energy required to maintain the normal activities of the body during complete rest in a warm atomosphere, 12-18 hours after the intake of food.
Choose the best answers:
1. ________________ is tough and thick white sheath that protects the inner parts of the eye.
(a) Sclera
(b) Conjunctiva
(c) Cornea
(d) Iris
2. ________ Cells are specialised cells that can be transformed into any kind of cells.
(a) Nerve
(b) Stem
(c) Heart
(d) Bone
3. Maintenance of constant internal environment of the body is known as ____________
(a) Homeostasis
(b) Homeophytes
(c) Homeokinesis
(d) Homeophilics
4. In the absence of oxygen, glucose is broken down in to _______________
(a) Lactic acid
(b) Citric acid
(c) Acetic acid
(d) Nitric acid
5. The process of air passing in and out the lungs are called __________
(a) Inhalation
(b) Exhalation
(c) Breathing
(d) None of these
6. Osmosis is the movement of water molecules from ___________
(a) Higher concentration to a region of lower concentration.
(b) Lower concentration to a region of higher concentration.
(c) Neutral
(d) None of these.
7. The erythrocyte is placed in __________ solution which has lesser concentration of solutes and greater concentration of water than in the cytoplasm.
(a) Hypotonic
(b) Hypertonic
(c) Neutral
(d) Acidic
Fill in the blanks:
1. _________ is the structural and functional unit of living organisms.
2. The largest cell is egg of an __________.
3. __________ is a good example for anaerobic respiration.
4. __________ nerve is located at the end of the eyes behind the retina.
5. The size of the cells are measured in units of __________.
Match the following:
1. Carbohydrates – CO2 Water and heat
2. Glucose – Amino Acid
3. Protein – Glucose
4. Amino acids – Cholesterol and other steroid
5. Fatty acids – Enzymes, hormone, protein
State true or false. If false, correct the statement:
1. In hypotonic condition, concentration of the external and the internal solution of the organism are same.
2. Diffusion is the movement of particles from an area of lower concentration to higher concentration.
3. Human beings are warm blooded in nature.
4. The larynx has fold of tissue which vibrate with the passage of air to produce sound.
5. Aqueous humour plays an important role in maintaining the shape of the eye.
Answers:
Choose the best answers:
1. Sclera 2. Stem 3. Homeostasis 4. lactic acid 5. Breathing 6. higher concentration to a region of lower concentration 7. Hypotonic
Fill in the blanks:
1. Cell 2. Ostrich 3. Fermentation 4. Optic 5. Microns
Match the following:
1.Carbohydrates – Amino acid
2.Glucose- Glycogen and other sugars
3.Protein- Glucose
4.Amino acids- Enzymes, hormones, proteins
5.Fatty acids – Cholesterol and other steroids-
State true or false. If false, correct the statement:
1.False
Correct answer: concentration of the external solution is less compared to concentration of internal sol.
2.False
Correct answer: Diffusion is the movement of particles from an area of higher concentration to lower concentration
3.True
4.True
5.True