std vii obtaining and utilising food
TRANSCRIPT
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STD VII
OBTAINING AND UTILISING FOOD
Q1. ALL LIVING BEINGS PROCURE ENERGY
FROM FOOD. NAME THE THREE LIFE PROCESS
WHICH HELP THEM DO THIS.
A1. THE THREE LIFE PROCESS ARE-
1.NUTRITION
2.TRANSPORTATION
3.RESPIRATION
Q2. WHAT ARE AUTOTROPHS ? NAME AN
ORGANISM OTHER THAN GREEN PLANTS THAT
IS AN AUTOTROPH.
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A2. AUTOTROPHS ARE THE ORGANISM THAT
MAKE THEIR OWN FOOD. ( AUTO - SELF, TROPH
-FEEDER)
Eg.. GREEN PLANTS.
ALGAE, WHICH ARE MICROORGANISMS, ARE
AUTOTROPHS.
Q3. NAME THREE TYPES OF HETROTROPHIC
NUTRITION ?
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A3. THE THREE TYPES OF HETROTROPHIC
NUTRITION ARE -
1.SAPROPHYTIC NUTRITION
2.PARASITIC NUTRITION
3.HOLOZOIC NUTRITION
Q4. WHAT ARE ENZYMES ?
A4. ENZYMES ARE THE SPECIAL CHEMICALS
THAT HELP IN THE BREAKDOWN OF FOOD INTO
SIMPLE SOLUBLE MOLECULES SO THAT THE
FOOD IS EASILY DIGESTED AND ABSORBED BY
THE BODY OF THE ORGANISM. FOR Eg. -
AMYLASE ( IN THE MOUTH) AND PEPSIN ( IN
THE STOMACH), etc.
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Q5. NAME THE STEPS INVOLVED IN THE
PROCESS OF HOLOZOIC NUTRITION.
A5. INGESTION - DIGESTION - ABSORPTION -
ASSIMILATION - EGESTION.
Q6. NAME 4 THINGS THAT GREEN PLANTS
NEED IN ORDER TO PHOTOSYNTHESISE.
A6. CO2, SUNLIGHT, CHLOROPHYLL AND
WATER.
Q7. WHAT IS THE JUICE SECRETED BY LIVER
CALLED ? WHAT DOES IT DO ?
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A7. LIVER SCERETS A JUICE CALLED BILE. IT
HELPS IN THE BREAK DOWN OF FATS INTO
FATTYACIDS, THUS HELPING IN THEIR
DIGESTION.
Q8. WHAT IS DIGESTION ?
A8. DIGESTION IS THE PROCESS IN WHICH THE
FOOD IS BROKEN DOWN INTO SIMPLE,
SOLUBLE MOLECULES, FOLLOWED BY ITS
ABSORPTION, BY THE ORGANISM'S BODY
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Q9. NAME A HOLOZOIC ANIMAL THAT IS NOT A
HERBIVORE, CARNIVORE OR OMNIVORE
A9. SPIDER / EARTHWORM.
Q10. WHAT ARE SAPROPHYTES AND PARASITES
?
A10. SAPROPHYTES
THE ORGANISMS THAT FEED ON THE DEAD
AND DECAYING ORGANIC MATTER ARE CALLED
SAPROPHYTES.
FOR Eg. : BACTERIA, FUNGI
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PARASITES:
THE ORGANISMS THAT ABSORB FOOD AND
NUTRITION FROM LIVING PLANTS AND
ANIMALS EITHER BY LIVING IN OR ON THEIR
BODY ARE CALLED PARASITES.
FOR Eg. : TAPEWORM, LICE, DODDER.
TAPEWORM
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Q11. WRITE BRIEFLY ABOUT THE PROCESS OF
NUTRITION IN AMOEBA.
A12. 1. AMOEBA, A MICROORGANISM,
OBTAINS NUTRITION BY THE PROCESS KNOWN
AS PHAGOCYTOSIS.IT SHOWS HOLOZOIC
NUTRITION.
2. IT STICKS OUT ITS PSEUDOPODIA OR FALSE
FEET AROUND THE FOOD.
3. IT ENGULFS THE FOOD AND THEN THE FOOD
IS DIGESTED INSIDE A FOOD VACUOLE IN THE
CELL, FOLLOWED BY ITS ABSORPTION AND
ASSIMILATION.
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* THE WASTE IS THEN COLLECTED IN A
CONTRACTILE VACUOLE AND IS EJECTED OUT.
Q12. WHY DO CARNIVOROUS PLANTS TRAP
INSECTS ? EXPLAIN HOW ONE SUCH PLANT
TRAP INSECTS?
A12. 1.CARNIVOROUS PLANTS TRAP INSECTS IN
ORDER TO GET THIER SUPPLY OF
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NITROGENOUS COMPOUNDS, FROM WHICH
THEY MAKE PROTIENS.
2.THEY DO THIS WITH THE HELP OF MODIFIED
LEAVES.
3.FOR Eg. : THE LEAVES OF SUNDEW, HAVE
HAIRS THAT SECRETE A STICKY LIQUID, THAT
GLISTEN IN THE SUN LIKE DEW.
4.INSECTS GET ATTRACTED TOWARDS THESE
DROPS, LAND ON THE HAIR, THE HAIR BEND
OVER THEM, AND KILL THEM.
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Q13. WHAT ARE SYMBIONTS. EXPLAIN WITH AN
EXAMPLE.
A13. SYMBIONTS ARE ORGANISMS THAT LIVE
TOGETHER FOR MUTUAL BENEFIT.THE PROCESS
IS SYMBIOSIS.
LICHENS, ARE SYMBIONTS, THAT CONSIST OF
FUNGI AND ALGAE. THE FUNGUS PROVIDES
MINERALS AND WATER TO THE ALGAE AND
THE ALGAE, IN RETURN, SUPPLIES FOOD THAT
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IT MANUFACTURES THROUGH
PHOTOSYNTHESIS TO THE FUNGUS.
Q14. WHAT IS THE DIGESTIVE JUICE IN THE
MOUTH CALLED? WHAT ENZYMES DOES IT
CONTAIN AND WHAT DOES IT DO ?
A14. 1.THE DIGESTIVE JUICE IN THE MOUTH IS
CALLED SALIVA.
IT IS SECRETED BY SALIVARY GLANDS.
2. IT CONTAINS ENZYMES CALLED AMYLASE,
WHICH ACTS ON THE STARCH PRESENT IN
FOOD, AND CONVERTS IT INTO SIMPLE SUGAR.
Q15. WHAT IS PERISTALSIS ? DOES IT OCCUR
ONLY IN THE OESOPHAGUS ?
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A15. 1.THE WAVELIKE MOVEMENT,
CONTROLLED BY INVOLUNTARY MUSCLES IS
CALLED PERISTALSIS.
2.IT HELPS IN PUSHING DOWN OF FOOD FROM
THE OESOPHAGUS TO THE STOMACH
THROUGH A SERIES OF CONTRACTIONS.
3.IT OCCURS ALL THE WAY DOWN THE
ALIMENTARY CANAL, BUT MAINLY IN THE
OESOPHAGUS. IT ALSO OCCURS IN THE SMALL
INTESTINE.
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Q16. THE JUICE PRODUCED IN THE STOMACH
CONTAINS AN ACID AS WELL AS AN ENZYME.
NAME THE ENZYME AND IT'S FUNCTION ?
A16. *THE DIGESTIVE JUICE PRODUCED IN THE
STOMACH CONTAINS HCl ACID ,WHICH KILL
GERMS
* AN ENZYME CALLED PEPSIN HELPS IN
BREAKING DOWN PROTIENS INTO SMALLER
AMINO ACIDS.
*THE ACIDIC MEDIUM CHANGES PEPSINOGEN
INTO ITS ACTIVE FORM PEPSIN.
Q17. WHAT HAPPENS TO THE UNDIGESTED
FOOD THAT REMAINS IN THE LARGE INTESTINE
?
A17. IN THE LARGE INTESTINE, SOME WATER IS
ABSORBED FROM THE UNDIGESTED FOOD,
WHILE THE REMAINING SEMI-SOLID WASTE IS
EGESTED OUT THROUGH THE ANUS.
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Q18. WHAT HAPPENS TO FOOD IN THE SMALL
INTESTINE ?
A18. 1.MOST OF THE DIGESTION AND THE
ABSORPTION OF FOOD IS COMPLETED IN THE
SMALL INTESTINE.
2. COMPLEX FOOD MOLECULES ARE BROKEN
DOWN INTO SIMPLE, SOLUBLE MOLECULES
WITH THE HELP OF CERTAIN ENZYMES THAT
ACT ON THEM.
3.THE WALLS OF THE SMALL INTESTINE
PRODUCE SOME ENZYMES WHILE SOME
ENZYMES ARE PRODUCED BY OTHER ORGANS
LIKE THE PANCREAS THAT SECRETES
PANCREATIC JUICE AND LIVER THAT SECRETES
BILE. THE ENZYMES ARE COLLECTIVELY CALLED
SUCCUS ENTERICUS.
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5.THE INNER WALL OF THE SMALL INTESTINE
HAS MILLIONS OF FINGERLIKE FOLDS CALLED
VILLI, WHICH INCREASE THE SURFACE AREA
FOR ABSORPTION OF FOOD.
6.DIGESTED FOOD PASSES THROUGH THE VILLI
AND ENTERS THE BLOOD FLOWING IN THE
CAPILLARIES IN THE VILLI.
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Q20. HOW MANY TEETH DOES AN ADULT
(HUMAN) HAVE ? DESCRIBE THE DIFFERENT
TYPES OF TEETH AND THEIR FEATURES.
A20. THERE ARE 32 TEETH IN A
ADULT(HUMAN). AN ADULT HAS 4 DISTINCT
TYPES OF TEETH. THEY ARE -
A.INCISORS : THEY ARE EIGHT IN NUMBER.
THEY HELP IN CUTTING THE FOOD.
B. CANINES : THEY ARE FOUR IN NUMBER. THEY
HELP IN TEARING THE FOOD.
C. PREMOLARS : THEY ARE 8 IN NUMBER,
WHICH HELP IN CHEWING AND GRINDING OF
FOOD.
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D. MOLARS : THEY ARE 12 IN NUMBER. THEY
ALSO HELP IN GRINDING THE FOOD.
Q21. HOW WOULD YOU SHOW THAT
CHLOROPHYLL IS NEEDED FOR
PHOTOSYNTHESIS ?
A21. ACTIVITY
1.TAKE A POTTED PLANT LIKE GARDEN CROTON
OR MONEY PLANT, THAT HAVE LEAVES WITH
YELLOW AND WHITE PATCHES. ONLY THE
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GREEN PORTION, IN SUCH LEAVES, CONTAINS
CHLOROPHYLL.
2. DESTARCH THE PLANT BY KEEPING IT IN A
DARK ROOM, FOR ATLEAST 48 HOURS.
2. TAKE A TEST TUBE CONTAINING ALCOHOL.
PLUCK OUT A LEAF AND PLACE IT INTO THE
TEST TUBE.
3.HEAT THIS IN A WATER BATH. HEATING THE
LEAF IN ALCOHOL REMOVES ALL THE
PIGMENTS FROM IT.
4.AS THE ALCOHOL TURNS GREEN AND THE
LEAF HAS LOST ITS COLOUR, TAKE THE LEAF
OUT AND WASH IT WITH WARM WATER.
5.PUT A FEW DROPS OF IODINE SOLUTION
OVER THE LEAF.
OBSERVATION: THE PARTS HAVING STARCH,
WILL TURN BLUE-BLACK.
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INFERENCE : ONLY THOSE PORTIONS OF THE
LEAF WHICH WERE GREEN, THAT IS, WHICH
CONTAINED CHLOROPHYLL, TURNED BLUE-
BLACK, AS ONLY THEY HAD CHLOROPHYLL.
THUS, CHLOROPHYLL IS ESSENTIAL FOR
PHOTOSYNTHESIS.
Q22. WITH THE HELP OF A FLOWCHART, SHOW
THE PROCESS OF DIGESTION IN HUMANS.
A22. FOOD IS TAKEN IN MOUTH
TEETH GRINDS IT
MOUTH SECRETES SALIVA, FOOD BECOMES
SOFT AND IS SWALLOWED AS BOLUS.
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FOOD MOVES DOWN THROUGH THE
OESOPHAGUS THROUGH PERISTALSIS
IN THE STOMACH, FOOD IS CHURNED, HCl KILLS
THE GERMS, THE PEPSIN ACTS ON THE
PROTIENS.
RENIN ACTS ON MILK
IN THE SMALL INTESTINE, BILE, PANCREATIC
JUICE AND OTHER ENZYMES ACT ON THE
FOOD.
ABSORPTION IS DONE BY VILLI
UNDIGESTED WASTE COMES TO LARGE
INTESTINE.
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WATER IS ABSORBED FROM THE WASTE.
WASTE IS EGESTED OUT THROUGH ANUS.
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DO IT YOURSELF.
Q1. IN WHAT FORM DO PLANTS STORE FOOD?
Q2. WHY SHOULD YOU NOT TALK WHILE
EATING.
Q3. NAME THESE-
A. A PARTIAL PARASITE
B. AN ENDOPARASITE
C. AN ECTOPARASITE.
D. INSECTIVOROUS PLANT.
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Q4. BY SEEING THE DIAGRAM, WRITE THE
NAME WITH ONE FEATURE OF EACH.
A. ____________. B. _____________
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C. The circled part is ________.
D. _______________.