BIOLOGY MODULE
CHAPTER 4
CHEMICAL COMPISITION IN THE CELL
WATER
.
- blood,
- lymphatic,
- excretory,
- digestive
systems,
- vascular tissues
..- polar
molecules attract
one another as
well as ions
Moisture
lubrication
..
-
The importance of
water
Medium for biochemical
reactions
High cohesion
NUCLEIC ACID
Store genetic information the form of a code
basic units nucleotides
State P, Q and R :
(1)P : .
(2)Q : .
(3)R : .
Deoxyribonucleic acid (DNA)
o
(4) .polynucleotide
- with the two strands twisted around each
other in the form of a (5)
o
can be found in (6) ,
Ribonucleic acid (RNA)
o
(9) .strand polynucleotide
can be found in (10).,
(11) .. and (12)
..
(7) .. and (8)
..
LO :
-
LIPIDS
state the elements in lipids
state the main types of lipids
state the components of fats and oils
explain the formation and breakdown of
fats and oils
compare and contrast saturated fats and
unsaturated fats
consists of .(13), . (14) and . (15)
types of lipids- (16) ., (17) ., (18) ., (19) .
and steroids.
fats and oils are (20) .
triglyceride is an (21) .that is formed through the (22) . of one
molecule of (23) .and three molecules of (24) .
(26)
3H2O
(27)
glycerol
-
(25) .
.
triglyceride(28)
water
waxes on the (29) . of the epidermis of leaves, fruits and seeds
- (30) . preventing the entry and evaporation of water
sebum- excreted from oil glands contains wax that soften the skin
Phospolipids- components in the formation of (31) .
Steroids- cholesterol
(32) . testosterone, oestrogen, progestrone
fats and oils- consists of one molecule (33) .and three molecules of (34)
.
fatty acids- consists of long (35) . chain with a different number carbon
atoms different fatty acids
Saturated fats
36
37
38
Fats
Differences
The presence of double
bonds between carbon
atoms in fatty acids
Ability to react with an
additional hydrogen atom
Condition at room
temperature
39
Unsaturated fats
40
41
42
43
Examples
LO :
CARBOHYDRATES
Fill in the blanks.
state the elements in carbohydrates
state the types of carbohydrates
explain the formation and breakdown of
disaccharides and polysaccharides
source of (44) .
consists of . (45), . (46) and . (47)
ratio of hydrogen atoms to oxygen atoms molecule is (48) .
Monosaccharides
Types of carbohydrates
Disaccharides
Polysaccharides
Glucose
Glucose
Examples:
(49) .
-in plants and fruits
(50) .
-in sweet fruits and honey
(51) .
- in milk
reducing
sugar
. . (52)
- reducing sugar
- malt sugar
Glucose
(53)
(54) .
- (55) .
cane sugar
-combination of hundreds of
monosaccharides
- formed by the condensation of (59)
.
-do not taste sweet and do not
crystallise
- (60) . in water
Examples :
(61) .
- in animals and yeast
(62) .
- in plants
(63) .
- cell walls of plants
Glucose
56
(57) .
- (58)
..
- milk sugar
Process of formation and breakdown
(64)
PROTEINS
Fill in the blanks.
(65)
LO :
-
state the elements in proteins
state the various structures of proteins
explain the formation and breakdown of
dopeptides and polypeptides
explain the meaning of essential amino
acids and non-essential amino acids
- made up of the elements (66) ., (67) ., (68) . and (69)
., (70) . and (71) .
- made up of monomers called (72) .
- a dipeptide consists of (73) .molecules of (74) . that are linked
together by a (75) .. through (76) ..
- conversely, a (77) .can be broken down into by means of (78) ..
Protein Structures
Primary structures
(79)
(80)
Secondary structures
-polypeptide coiled to form
an (81)
Tertiary structures
-the overall three-dimensional
shape of a polypeptide chain
(85)
- linear sequence of amino
acids in polypeptide chain
-helix(82)
Examples : enzymes, hormones,
antibodies, plasma protein
-folded into (83)
. sheets
Quarternary structures
- the combination of two or more
tertiary polypeptides that makes
up a protein
(86)
.. (84)
Types of amino acid (20
amino acid)
(87) ..
[9 amino acids]
-cannot be synthesised by
the body
- obtained from the diet
non-essential amino acids
[(89) . amino acids]
-(90) synthesised by
the body
- derived from other amino acids
- Why are animal proteins,
first class proteins?
(88) .
- Why are plant proteins,
second class proteins?
(91) .
ENZYMES
Fill in the blanks by using the words given.
biological
-
speed up
catalyst
Enzymes are (92) . .that (93) .biochemical reactions
in the cell.
General Characteristics of
Enzymes
(96)
(94)
(97)
(95)
(98)
(99)
Substrate
Lipid
(102)
(103)
(100)
Enzyme
(101)
amylase
protease
The sites of enzyme synthesis
The sites of protein synthesis
ssomiRboes - (104)
Intracellular enzymes
Extracellular enzymes
Definition (105)
Definition (107)
Examples :(106)
Examples :(108)
Production of extracellular enzymes
(112)
L:
(109)
O: oolgy apparatus
(113)
K:
(110)
N: endoplasmic
reticulum
(114)
J:
(111)
M: Nucleus
Proteins/ enzymes are synthesized in
K : . ..(115)
transported through the
spaces
N : . ..(116)
proteins wrapped in . (117) that bud
off from the sides of the N: .
(118)
L : . (119)
fuse with the membrane of the
O : . .(120).
Secretory vesicles
bud off from the . (121) membrane and
travel to the . (122) membrane
caietv iets
Lock and key mechanism
Releasing the proteins outside Rearrange
the cell as the jumbled up
[myzesne] . (123) words to the correct terms:
. .(124)
-a distinctive shape that
complements its substrate
- Choose the suitable substrate for the enzyme and complete the schematic diagram below to
show the mechanism of enzyme action on a suitable substrate
Enzyme
Substrate
(125)
(126)
Substrate
Enzyme + Substrate
Enzyme-Substrate Complex
(127)
Product
Enzyme + Product
Lock and Key Hypothesis : Conclusion
128
129
130
Factors affecting enzyme activity
Factors
Explaination
Complete the diagram
Temperature
(133) temperature
(37oC-40oC)
- reaction at maximum rate
(134) temperature
(above 40oC)
- enzymes are denatured
- denaturation is irreversible
the rate of enzyme activity
(135)
(132) temperature
- reaction takes place slowly
temperature (oC)
(139)
pH
- example :
Pepsin (136) .
Trypsin (137).
Amylase (138)..
- reversible
the rate of enzyme activity
optimum pH
- pH at which the rate of
reaction is at the maximum
1 2 3 4 5 6 7 8 9 10
pH
- the rate of reaction is directly
propotional to the substrate
concentration until the reaction reaches a
maximum rate
- an increase in substrate concentration
will speed up the reaction until the
reaction reaches a (140)
(143)
the rate of enzyme activity
Substrate
concentration
- after the maximum rate the enzyme is
- limiting factors- (142)
Enzyme
concentration
Substrate concentration
..
- an increase in enzyme
concentration will (144)
the rate of reaction until the reaction
reaches a maximum rate
- limitinf factor- (145) .
(146)
the rate of
enzyme activity
said to be (141)
Enzyme concentration
10
The uses of enzymes
Match the enzyme to its uses
Enzymes
-
In detergents
(147)
Lipase
Uses
tenderise meat
skinning of fish
used to remove hair
from hides
to convert starch to
sugar in the making
of syrup
(148)
-
Amylase
breaks down the cell
wall of the
seaweeds
(extracting algae
jellu from seweeds
softening vegetables
removal of seed
coats from cereal
grain
(149)
Proteases
(150)
Cellulases
(151)
is used in the
ripening of cheese
to produce flavour in
cheese
to break up fats in
meat
effectively dissole
proteins stains
Enzymes
LO:
state what enzyme are
explain why enzymes are needed in life processes
list the general characteristics of enzymes
relate the name of enzyme to substrate
state sites where enzymes are synthesised
state the meaning of intracellular and extracellular enzymes
explain the involvement of specific organelles in the production of extracellular
enzymes
explain the effects of pH, temperature, enzyme concentration and substrate
concentration on enzyme activity
explain the mechanism of enzyme action
relate the mechanism of enzyme action with pH, temperature, enzyme
concentration and substrate concentration
explain the uses of enzymes in daily life and industry usng examples
11
The Importance of Chemical Composition in Cells
LO :
- predict the consequences of defiency in
carbohydrates, proteins, lipids or enzymes in
the cell
Complete the table below
Chemical
components
Function
Consequence of defiency
(152)
(157)
(153)
(158)
(154)
(159)
(155)
(160)
(156)
(161)
Water
Lipids
Carbohydrates
Proteins
Enzymes
12
STRUCTURAL QUESTIONS:
1
(a)
Enzymes are widely used in our daily life and industries.
Explain how enzymes act in :
(i)
helping to cook meat.
...
...
...
[2 marks]
(ii)
extrating agar from seaweeds.
...
...
...
[3 marks]
Figure 1(a) shows a reaction catalysed by lipase.
R:
Q:
S:
P:
Figure 1(a)
(a)
(i)
Label P,Q, R and S i Figure 1(a).
[4 marks]
(ii)
State two characteristics of P.
...
...
...
[2 marks]
13
(b)
(i)
State the principle of enzymic reaction as shown in Figure 1(a).
...
[1 mark]
(ii)
What can you deduce about the enzyme lipase based on Figure
1(a)?
...
...
[1 mark]
(c)
Enzymes are used widely in industries.
State one use of lipase in food industry.
....
[1 mark]
(d)
The temperature at which a lipase reaction takes place is increased to
more than 60OC.
State the effect on the quantity of the product. Explain your answer.
....
....
..
[2 marks]
(e)
Figure 1(b) shows a box of washing powder.
Figure 1(b)
A housewife uses cold water to wash her clothes with brand X washing
powder. The cleaning is less effective.
Using the above information, explain why.
....
....
....
[2 marks]
14
(a)
Diagram 2.1 shows a mechanism of an enzyme reaction.
Draw the diagram in the spaces III and IV provided in Diagram 2.1
to complete the mechanism of the enzyme reaction.
Diagram 2.1
(b)
In a food preparation process, a housewife carries out the
following steps:
Step 1 : Marinate pieces of meat with strips of unripe papaya in a
basin.
Step 2: Immerse the basin in a container filled with water at 40oC
for 30 minutes as Diagram 2.2
.
Diagram 2.2
Explain why the housewife carries out Step 1 and Step 2.
...
...
...
...
...
...
[4 marks]
15
