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.

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 ?

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.

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 ?

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

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

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

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.

* 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

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.

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

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 ?

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.

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.

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.

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.

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.

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

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.

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.

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.

WATER IS ABSORBED FROM THE WASTE.

WASTE IS EGESTED OUT THROUGH ANUS.

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.

Q4. BY SEEING THE DIAGRAM, WRITE THE

NAME WITH ONE FEATURE OF EACH.

A. ____________. B. _____________

C. The circled part is ________.

D. _______________.