biology int 2 section 2 revision.ppt
TRANSCRIPT
-
7/24/2019 Biology Int 2 Section 2 revision.ppt
1/22
Cells & Enzymes
Enzymes
Made of proteinPresent in
all living cells
Converts substrates
into products
Biological
catalysts
Increase the rate of
chemical reactionsRemain unchanged
by chemical reaction
-
7/24/2019 Biology Int 2 Section 2 revision.ppt
2/22
ProductSubstrate
Chemical Reactions
chemical reaction ta!es place "hen one or
substances is chemically changed into one or more
different substances#
Chemical reactions ta!e place in cells all the time#
Enzyme
Catalase
$ydrogen
pero%ideater ' o%ygen
Manganese
dio%ide
Catalyst
-
7/24/2019 Biology Int 2 Section 2 revision.ppt
3/22
Catalysts
catalyst is a substance "hich speeds up a chemicalreaction( "ithout itself being changed by the
reaction#
)# hen a catalyst is present( less energy is neededto get the chemical reaction started#
*# hen a catalyst is present( the speed of the
chemical reaction is faster#
+# lthough a catalyst helps a chemical reaction to
happen( it is unchanged at the end of the reaction#
-
7/24/2019 Biology Int 2 Section 2 revision.ppt
4/22
Biological Catalysts
,he biological catalyst present in the cytoplasm ofplant and animal cells that speeds up the brea!do"n
of hydrogen pero%ide is called C,-SE#
$ydrogen
pero%ide.%ygen ' "ater
catalase
-
7/24/2019 Biology Int 2 Section 2 revision.ppt
5/22
*#* /ature of Enzymes
,he biological catalyst present in the cytoplasm ofplant and animal cells that speeds up the brea!do"n
of hydrogen pero%ide is called C,-SE#
Catalase cannot speed up any other reaction# It is
SPECI0IC to this reaction#
Catalase$ydrogen
pero%ideater ' o%ygen
-
7/24/2019 Biology Int 2 Section 2 revision.ppt
6/22
.ne Enzyme 1 .ne Reaction
,here are thousands of different enzymes in yourbody#
hy are there so many different enzymes2
Each enzyme has its o"n uni3ue protein structure
and shape( "hich is designed to match or
C.MP-EME/, its substrate#
-
7/24/2019 Biology Int 2 Section 2 revision.ppt
7/22
-
7/24/2019 Biology Int 2 Section 2 revision.ppt
8/22
-
7/24/2019 Biology Int 2 Section 2 revision.ppt
9/22
-oc! & 4ey $ypothesis
n enzyme only acts on one type of substance( or substrate#
,herefore( the enzyme is said to be SPECI0IC to its one substrate#
,he shape of the active site 5binding site6 of the enzyme( matches the
shape of the substrate# llo"ing the t"o molecules to bind during the
chemical reaction#
,his theory of enzyme action is called the 7loc!8and8!ey9 hypothesis#
-
7/24/2019 Biology Int 2 Section 2 revision.ppt
10/22
M.:IE
-
7/24/2019 Biology Int 2 Section 2 revision.ppt
11/22
-
7/24/2019 Biology Int 2 Section 2 revision.ppt
12/22
*#+ =sing a Control
hy is it necessary to include a control e%perimentin an investigation2
controlis an e%periment that allo"s a
comparison "ithin an investigation in order toensure that the conclusions dra"n from the results
are valid#
-
7/24/2019 Biology Int 2 Section 2 revision.ppt
13/22
*#+ =sing a Control
.nly one variable should be altered in aninvestigation( this is said to be the altered variable#
It is important to ensure that all other potential
variables are !ept the same in the investigation(
these are called the controlled variables#
hat "as the altered variable in the last
investigation you carried out2
hat "ere the controlled variables in the last
investigation you carried out2
-
7/24/2019 Biology Int 2 Section 2 revision.ppt
14/22
Enzymes involved in brea!do"n reactions
Catalase$ydrogen pero%ide ater ' .%ygen
mylase
Starch Maltose
-ipase0at 0atty acids ' >lycerol
PepsinProtein mino acids
-
7/24/2019 Biology Int 2 Section 2 revision.ppt
15/22
*#? Synthesis reactions
>lucose is used by
leaves as energy
source or transportedto root for storage#
-eaves ma!e glucose#
Roots convert glucose
into >8)8P#
Phosphorylase
converts >8)8P into
starch#
-
7/24/2019 Biology Int 2 Section 2 revision.ppt
16/22
*#? Synthesis reactions
phosphorylase
glucose-1-phosphate starch
hat is phosphorylase2
Phosphorylase is an enzyme that synthesises starch#
hat is substrate of phosphorylase2
>lucose8)8phosphatehat is the product2
Starch
-
7/24/2019 Biology Int 2 Section 2 revision.ppt
17/22
*#? Synthesis reactions
phosphorylase
glucose-1-phosphate starch
mylase catalyses the brea!do"n of starch toproduce maltose#
$o" is starch produced2
-
7/24/2019 Biology Int 2 Section 2 revision.ppt
18/22
*#@ Effect of $igh ,emperature
/otes on ;enaturation /otes on .ptimum temp
A Optimum conditionsare the conditions
at "hich an enzymes "or!s best
A Rate of reactions may be affected by
temperature and p$
-
7/24/2019 Biology Int 2 Section 2 revision.ppt
19/22
*#@ Effect of $igh ,emperature
/otes on ;enaturation/otes on
.ptimum temp
hat happens to the activity of an enzyme at high
temperatures2
-
7/24/2019 Biology Int 2 Section 2 revision.ppt
20/22
Movie
Effect of p$ on enzymes
hen the p$ changes out"ith optimal conditions( the shape
of the active site of the enzyme alters and the enzyme is
denatured#
-
7/24/2019 Biology Int 2 Section 2 revision.ppt
21/22
Effect of p$ on enzyme activity
Most enzymes "or! best at a p$ close to neutral 5p$6( but
there are some e%ceptions# Pepsin( an enzyme found in thestomach( has an optimum p$ of *#
-
7/24/2019 Biology Int 2 Section 2 revision.ppt
22/22
Enzyme Substrate Product5s6 ;egradationor synthesis2
mylase Starch Maltose ;egradation
Catalase $ydrogenpero%ide
.%ygen and"ater
;egradation
Pepsin Protein mino acids ;egradation
Phosphorylase >lucose8)8
phosphate
Starch Synthesis
-ipase 0at mino acids ;egradation
Enzyme Summary