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Biology
Enzymes
catalyst - a substance that increases the rate of a chemical reaction and is not changed by the
reaction.
enzymes - proteins that are involved in all metabolic reactions, biological catalysts that speed up
the rate of a chemical response with out being changed, necessary to all living organisms as they
maintain reaction speeds of all metabolic reactions. enzymes are specific to one particular
substrate as the the enzyme is a complimentary shape to the substrate. the product is made from
the substrate and is released
enzymes are specific to one substrate as the active site of that enzyme is complementary to the
shape of the substrate ( lock and key )
when the substrate moves into the enzymes active site it is known as enzyme-substrate complex
after the reaction has occurred the products leave the enzymes active site
Biology 1
, Enzymes work faster at the optimum temperature in the human body its 37C
Heating the enzyme more than the temperature will denature the irreversible enzyme
But increasing the temperature from 0 will make them work fast after the optimum temperature
they will start to renature as they have more kinetic energy
the optimum pH for most enzymes is 7 but in the stomach its 2 because the stomach has acidic
conditions and in the duodenum its 8 or 9 as it has alkaline conditions
if the pH is too high or low the bonds that hold the amino acid chain together to make up the
protein can be destroyed, which also changed the shape of active site
Practical
Effect of temperature on amylase :
1. starch solution is heated
2. iodine is added to wells of spotting tile
3. amylase is added to the starch solution and mixed
4. every minute, droplets of solution are added to a new well of iodine solution
5. this is continued til iodine stops turning blue-black ( no more starch left, amylase has broken
it all down )
6. the quicker the reaction is completed the faster the enzyme is working
Effect of pH on amylase
1. place drops of iodine solution on tile
2. label a test tube with the pH to be tested
3. add 2cm^3 of amylase in test tube
Biology 2
, 4. add 1cm^3 of buffer solution to test tube
5. add 2cm^3 of starch to the test tube with amylase start a stopwatch whistle mixing
6. after 10 secs add another drop of mixture on the second drop of iodine
7. another 10 secs later add another drop of mixture on the second drop of iodine
8. repeat every 10 secs till the iodine solution remains orange-brown
9. the quicker the starch has been digested and so the better the enzyme works at that pH
Plant Nutrition
photosynthesis - the process by which plants manufacture carbohydrates from raw materials
using energy from light
the carbohydrate glucose is made from carbon dioxide and water. oxygen is released as a waste
product . this reaction requires energy which is obtained by the pigment chlorophyll tapping light
from the sun
light
carbon dioxide + water. ———————————- glucose + oxygen
chlorophyll
light
6CO2 + 6H2O ———————————- C6H12O6 + 6O2
chlorophyll
Biology 3
, co2 - diffuses into the leaves through stomata
water - taken up by the roots and transported through the xylem to the leaves
glucose - used to make substances in the plant ; used in respiration to release energy
oxygen - diffuses out the leaf through the stomata ; used in respiration
chlorophyll - green pigment that is found in chloroplasts within plant cells it reflects green
light, giving the plants their color. chlorophyll absorbs light energy its role is to transfer
energy from light in chemicals, for the synthesis of carbohydrates such as glucose,
photosynthesis will not take place without chlorophyll
the carbohydrates made by the plants can be used in the following ways :
converted into starch molecules which act as an effective energy store
converted into cellulose to build cell walls
glucose can be used in respiration to provide every
converted to sucrose for transport in phloem
as nectar to attract insects for pollination
chlorophyll contains magnesium and nitrogen,, plants obtain these elements in the form of
mineral ions, actively absorbed from the soil by root hair cells
mineral ion function deficiency
causes yellowing between the
magnesium to make chlorophyll
veins of leaves ( chlorosis )
source of nitrogen needed to
causes stunted growth and
nitrate make amino acids ( to build
yellowing of leaves
proteins )
Biology 4
Biology
Enzymes
catalyst - a substance that increases the rate of a chemical reaction and is not changed by the
reaction.
enzymes - proteins that are involved in all metabolic reactions, biological catalysts that speed up
the rate of a chemical response with out being changed, necessary to all living organisms as they
maintain reaction speeds of all metabolic reactions. enzymes are specific to one particular
substrate as the the enzyme is a complimentary shape to the substrate. the product is made from
the substrate and is released
enzymes are specific to one substrate as the active site of that enzyme is complementary to the
shape of the substrate ( lock and key )
when the substrate moves into the enzymes active site it is known as enzyme-substrate complex
after the reaction has occurred the products leave the enzymes active site
Biology 1
, Enzymes work faster at the optimum temperature in the human body its 37C
Heating the enzyme more than the temperature will denature the irreversible enzyme
But increasing the temperature from 0 will make them work fast after the optimum temperature
they will start to renature as they have more kinetic energy
the optimum pH for most enzymes is 7 but in the stomach its 2 because the stomach has acidic
conditions and in the duodenum its 8 or 9 as it has alkaline conditions
if the pH is too high or low the bonds that hold the amino acid chain together to make up the
protein can be destroyed, which also changed the shape of active site
Practical
Effect of temperature on amylase :
1. starch solution is heated
2. iodine is added to wells of spotting tile
3. amylase is added to the starch solution and mixed
4. every minute, droplets of solution are added to a new well of iodine solution
5. this is continued til iodine stops turning blue-black ( no more starch left, amylase has broken
it all down )
6. the quicker the reaction is completed the faster the enzyme is working
Effect of pH on amylase
1. place drops of iodine solution on tile
2. label a test tube with the pH to be tested
3. add 2cm^3 of amylase in test tube
Biology 2
, 4. add 1cm^3 of buffer solution to test tube
5. add 2cm^3 of starch to the test tube with amylase start a stopwatch whistle mixing
6. after 10 secs add another drop of mixture on the second drop of iodine
7. another 10 secs later add another drop of mixture on the second drop of iodine
8. repeat every 10 secs till the iodine solution remains orange-brown
9. the quicker the starch has been digested and so the better the enzyme works at that pH
Plant Nutrition
photosynthesis - the process by which plants manufacture carbohydrates from raw materials
using energy from light
the carbohydrate glucose is made from carbon dioxide and water. oxygen is released as a waste
product . this reaction requires energy which is obtained by the pigment chlorophyll tapping light
from the sun
light
carbon dioxide + water. ———————————- glucose + oxygen
chlorophyll
light
6CO2 + 6H2O ———————————- C6H12O6 + 6O2
chlorophyll
Biology 3
, co2 - diffuses into the leaves through stomata
water - taken up by the roots and transported through the xylem to the leaves
glucose - used to make substances in the plant ; used in respiration to release energy
oxygen - diffuses out the leaf through the stomata ; used in respiration
chlorophyll - green pigment that is found in chloroplasts within plant cells it reflects green
light, giving the plants their color. chlorophyll absorbs light energy its role is to transfer
energy from light in chemicals, for the synthesis of carbohydrates such as glucose,
photosynthesis will not take place without chlorophyll
the carbohydrates made by the plants can be used in the following ways :
converted into starch molecules which act as an effective energy store
converted into cellulose to build cell walls
glucose can be used in respiration to provide every
converted to sucrose for transport in phloem
as nectar to attract insects for pollination
chlorophyll contains magnesium and nitrogen,, plants obtain these elements in the form of
mineral ions, actively absorbed from the soil by root hair cells
mineral ion function deficiency
causes yellowing between the
magnesium to make chlorophyll
veins of leaves ( chlorosis )
source of nitrogen needed to
causes stunted growth and
nitrate make amino acids ( to build
yellowing of leaves
proteins )
Biology 4
