Khamis, 14 Jun 2012

skema jawapan biologi form 4 pep.pertengahan tahun 2012

SKEMA JAWAPAN PEPERIKSAAN PERTENGAHAN TAHUN 2012
BIOLOGI KERTAS 2

NO.
SCORING CRITERIA
MARK
REMARK
1 (a)
(i) able to label the structures of P,Q,R and S
P : nucleus
Q : chloroplast
R : Mitochondria
S : vacuole

2
4 correct= 2m
2-3 correct =1m
0-1 correct=0m

2 m

(ii) able to state a function of the structures P and R

P : controls all the activities which take place in the cell (example the synthesis of proteins is regulated by coded information contained in the chromosomes)

R : sites of cellular respiration//release energy through the oxidation of food substances ( such as glucose) // generate energy in the form of ATP ( which can be used readily by cells)


1



1
Accept any suitable answer




2m

(iii) able to state one similarity between Q and R
Ø  Both have double menbrane
1

1m

(iv) able to explain why organelle Q present in a green plants only

F1 : green plants cells need chlorophyll that contain in this organelle/chloroplast
E1 : chlorophyll absorbs/traps light energy (and convert light energy into chemical energy during photosynthesis.



1

1




2m

(v) able to exlplain how S maintain cell turgidity

F1 : the cell sap in the S/vacuole contains water and dissolved substances
E1 : when water enter/diffuse into the cell(by osmosis), it fills up the vacuole causing it to expand
E2 : this creates turgor pressure within the cell and maintains its turgidity


1

1

1




3m
1(b)
Able to state two differences between a palisade cell and cheek cell

Palisade cell
Cheek cell
Cell wall present
Cell wall absent
Chloroplast is present
Chloroplast is absent
A large central vacuole is present
No large central vacuole
Have a fixed shape
Do not have a cheek cell



1
1
1
1

1



Any 2


2m



TOTAL
12 M
2(a)
Able to label the structures

J- hydrophilic heads
K-hydrophobic tails
L-pore protein
M-carrier protein


1
1
1
1





4m
2(b)
Able to name the model
Ø  Fluid mosaic model
1

1m
2(c)
(i) able to state the characteristics
Ø  Semi permeable
1






4m

(ii) able to explain the substances

P1: glucose/amino acids/nucleic acids because large polar molecule/not soluble in lipid

P2 : Mg2+/Na+/Cl- (any suitable ions) because the molecule is ions/charged


1


1


(iii) able to state the structure
Ø  Carrier protein/M
1
2(d)
Able to name two factors
Ø  Polarity
Ø  Size

1
1


2m
2(e)
Able to explain the statement
Ø  To make plasma membrane more rigid and stable/flexible and dynamic

1


1



TOTAL
12M
3(a)
Able to label X,Y and Z in figure 3.1
X : lactose
Y : glucose
Z : galactose

1
1
1

3-2 correct= 2m
1 correct =1m


2m
3(b)
Able to state the characteristics of enzyme

P1 : do not destroyed by the reactions they catalyst
P2 : highly specific
P3 : can catalysed the reaction in either direction/reversible


1
1
1



3m
3 (c)
Able to explain different effectiveness of cleaning in different temperature

F1 : all (the organic) stain remove from the cloth at 400C
E1 : because enzyme is active // can hydrolysed organic stain
F2 : (the organic) stain is partially remove at 00C
E2 : because enzyme is not active//cannot hydrolysed organic stain
F3 : (the organic) stain is not remove at 600C
E3 : the enzyme cannot hydrolysed (the organic) stain totally because enzyme is denatured



1
1

1
1

1
1




5m
3(d)
Able to predict the effectiveness of cleaning her cloth

F : (the organic) stain is partially removed
E1 : lime juice cause medium of cleaning become acidic
E2 : enzyme cannot hydrolysed the organic stain


1
1
1



2m



TOTAL
12M
4(a)
Able to answer what is the cell
Ø  The basic unit of life/living thing

1


1m
4(b)
Able to name cell P and tissue Q
P : epithelium cell
Q : smooth muscle tissues


1
1



2m
4(c)
Able to explain the organization and functions of tissues Q and stomach
Tissue Q :
Ø  Made up of (many) smooth muscle cell
Ø  Perform/ carry out (specific function) muscle contraction/contraction of stomach wall
Stomach :
Ø  Made up of (many) tissues Q/epithelial tissues and smooth muscle tissues
Ø  Perform / carry out (specific function) the digestion of food/protein



1
1


1

1





2m




2m
4(d)
(i) able to state the level R of the cell organisation
Ø  Organ
(ii) able to state the formation of the level R

R : an organ is formed by two or more type of tissues working together to perform a particular function

1


1


1


1
4(e)
Able to  explain the differentiation process of cell P to secrete gastric juice in stomach

P1 : cell P grows and changed their structure
P2 : they are organized into tissues that lining the inner space of stomach
P3 : cell P become specialized and adapts to become a group of cell and form gastric glands
P4 : in form of tissues, secretion of gastric juices more efficiently



1
1

1

1









3m



TOTAL
12
5(a)
Able to give the name of the process
X : simple diffusion
Y : facilitated diffusion
Z : osmosis

1
1
1


3m
5(b)
(i) able to give definition of osmosis

F : the movement of water molecule from higher concentration of water molecule/hypotonic solution to lower concentration of water molecule/hypertonic solution through semi-permeable membrane (until dynamic equilibrium is achieve)


1



1m
5(b)
(ii) able to explain the preservation of fish

P1 : immersed fish in the natrium solution
P2 : water in fish diffuse out by osmosis cause bacteria in fish die


1
1



2m
5(c)
Able to state the similarities and differences between facilitated diffusion and active transport

Similarities
S1 : both require protein molecule
S2 : both the movement of substances from higher concentration molecule substances to lower concentration
S3 : both occur through plasma membrane


Differences
D1 : facilitated diffusion no need energy while active transport need energy
D2 : in facilitated diffusion, the movement of substances down the concentration gradient while active transport against concentration gradient.





1
1


1



1

1






Any one







Any two




1m







2m






5(d)
Able to explain how sodium solution move out.

P1 : the sodium solution in the cell move out by active transport/ against concentration gradient
P2 : energy/ATP is required
P3 : sodium ion bind with active site of the carrier protein
P4 : carrier protein is modified/change their shape (to move out the sodium ion)


1

1
1

1



3m



TOTAL
12m
6(a)
(i) able to state what is the internal environment and physical and chemical factors

F : consist of the interstitial fluid and the blood plasma
P1 : physical factors : temperature/blood pressure/osmotic pressure
P2 : chemical factors : pH value/salt/sugar content



1
1

1





3m
6(a)
(ii) able to explain the importance of regulating the optimum condition of the internal environment

F : oppose the effects changes
E1 : ensure optimum cellular activities
E2 : stable internal environment
E3 : enable organism to live in wider range of habitats
E4 : metabolic activities/ physiological process can still continue(even though the external environment change)
E5 : organism able to control metabolic rate
E6 : more efficient and optimal metabolism in the cell



1
1
1
1
1

1
1







6m
6(b)
(i) able to name the system involves the organ in diagram 6.1 and explain how the organ react to maintain the body temperature at 370C in a hot day

F1 : integumentary system
E1 : erectors muscle relaxes
E2 : to enable the hair follicle lie down
E3 : less/thin layer of air trap
E4 : sweat gland active secrete sweats
E5 : increase amount of heat lost to the surroundings











1
1
1
1
1
1






5m
6(b)
(ii) able to state another two system that help to regulate body temperature and describe how does the system work in hot day

F1 : nervous system
E1 : when body temperature rises, the receptors in the skin detect the changes
E2 : information transmitted to the brain /hypothalamus
E3 : brain/hypothalamus activates various effectors/sweat gland/blood vessels

F2 : circulatory system
E4 : arterioles/ blood vessel (in epidermis) dilate
E5 : more blood flows to the skin //more heat release

F3 : endocrine system
E6 : produces hormones to reduces the metabolic rate
E7 : produces hormones to reduces production of heat




1
1

1
1


1
1
1

1
1
1




Any 2F and 4E




6m



TOTAL
20 m
7(a)
(i) able to explain the process experienced by plant cell after immersion in 30% sucrose solution for 30 minutes

E1 : cell undergoes plasmolysis
E2 : 30% sucrose solution is hypertonic than the plant cell
E3 : water molecules diffuse out of the large central vacuole by osmosis
E4 : both the vacuole and cytoplasm shrink
E5 : plasma membrane pulls away from the cell wall
E6 : the cell become flaccid
E7 : the cellulose cell wall does not shrink because it is strong



1
1

1

1
1
1
1



Any 6



6m
7(a)
(ii) able to describe how do you make the plant cell in retains its normal shape

E1 : by immersing the plant cell Q in 0.5% sucrose solution/isotonic solution
E2 : 0.5% sucrose solution is isotonic to the plant cell sap
E3 : water diffuses into and out of the cell at equal rate
E4 : by osmosis
E5 : no net movement of water across the plasma (causes the cell retains its normal shape)



1

1

1
1
1



Any 4




4m
7(b)
Able to explain the concepts applied in the preservation of the pickled papaya

E1 : papaya slices is soaked in a concentrated sugar solution
E2 : these preservatives/sugar solution will make the solution outside the papaya slices/fruit/food more concentrated/hypertonic compared to the content of the papaya cells
E3 : water molecules diffuse into the papaya cells by osmosis
E4 : the cells in papaya become dehydrated/flaccid//the food become dry
E5 : causing the microorganism/bacteria/fungus cannot survive
E6 : (at the same time) microorganism/bacteria/fungi also lose water by osmosis(to surrounding solution) and will eventually die
E7 : as a result, the papaya/ fruit can last longer



1

1



1

1

1

1


1



Any 6



6m
7(c)
Able to explain the differences between the process experienced by the red blood cell X and Y after being immersed for half an hour.

Red blood cell X
Red blood cell Y
Cell X undergo crenation
Cell Y undergo heamolysis
3 % sodium chloride solution hypotonic compared to cytoplasmic fluid cell X
0.1 % sodium chloride solution hypertonic compared to cytosplamic fluid cell Y
Water molecules diffuse from cell X to 3 % sodium chloride solution by osmosis
Water molecules diffuse from 1% sodium chloride solution into cell Y by osmosis
Cell X shrink/shrivel/plasma membrane of the cell X crinkles up
Cell Y swells up and eventually burst.





1

1



1



1







4m

















TOTAL
20M
8(a)
Able to state the importance of water in cells

E1 : as a medium for biochemical reaction in the cell
E2 : a good solvent for many substances
E3 : as a transport medium within cells / between the cell
E4 : as a major component of protoplasm
E5 : allows the chemical changes to take place in solution
E6 : provide moisture to the respiratory surface/alveoli to enable respiratory gases/oxygen and carbon dioxide to dissolve
E7 : provide support for non-woody/herbaceous plant when the cell turgid
E8 : maintain body temperature


1
1
1

1
1

1


1

1


Any 6


6m
8(b)
(i) able to describe the structure of nucleic acids

E1 : nucleic acids contains carbon, hydrogen, phosphorus and nitrogen
E2 : basic unit of nucleic acids is nucleotide
E3 : nucleotide consist of pentose sugar, phosphate and nitrogen base
E4 : two type of nucleic acids : RNA( ribonucleic acids) and DNA (deoxyribonucleic acids)
E5 : DNA consists of two strands polynucleotide twisted into a double helix
E6 : RNA consist of single strands of polynucleotide


1

1
1

1

1

1


Any 4


4m
8(b)
(ii) able to state importance of nucleic acids in cells

E1 : carry genetics information (in all living cell)
E2 : control all the main activities in the cell
E4 : (carry genetics information) for synthesis of proteins


1
1
1


Any 2


2m
8(c)
(i) able to name structures A,B, C and D

A : primary structure of protein
B : secondary structure of protein
C : tertiary structure of protein
D : quarternary structure of protein


1111



4m
8(c)
(ii) able to explain the type of amino acids and classes of protein

Two type of amino acids :
E1 : essential amino acids : amino acids cannot be synthesised by body cell
E2 : non-essential amino acids : amino acids can be synthesised by body cell

Two classes of protein :
E3 : first class protein : contain all the essential amino acids
E4 : second class protein : lacks a few of essential amino acids




1

1



1

1





4m



TOTAL
20 M
9(a)
(i) able to name the stages and state two importance of mitosis

P : metaphase
Q : prophase
R : anaphase

Importance :
P1 : produced new cells
P2 : replace dead and damage cells
P3 : basic of asexual reproduction



1
1
1


1
1
1








Any 2




3m



2m
9(a)
(ii) able to rearrange the stages in correct sequence and draw daughter cells

Q  >> P >> R

Drawing :
ü  Must have two daughter cells
ü  Correct number of chromosomes – 4
ü  Label at least 3:
Ø  Chromosomes/chromatid
Ø  Nuclear membrane
Ø  Cell membrane
Ø  Nucleolus




1


2
1
1




5m
9(b)
Able to explain the differences of cytokinesis process in animal and plant cell

F1 : cytokinesis in animal cell occur by formation of cleavage furrow while in plant occur by the formation of cell plate

Cytokinesis in animal cell
E1 : actin filaments contract to pull a ring of plasma membrane inward
E2 : forming a groove called cleavage furrow
E3 : (cleavage furrow) pinches the equator of the cell

Cytokinesis in plant cell
E4 : a vesicle gather at an equator(between two nuclei)
E5 : (vesicle) fuse to form a cell plate
E6 : (cell plate) grow outwards and fuse with the plasma membrane




1




1

1
1


1
1
1



Any 6



6m
9(c)
Able to explain the technique of tissues culture

F1 : method used tissues culture/cloning
E1 : tissues from parent plant/stem/shoot/leaves is taken out
E2 : tissues is sterile to prevent infection of microorganism
E3 : cultured in sterile medium(containing nutrients and growth hormones)
E4 : cells divide by mitosis to form a callus
E5 : plantlets transferred to the soil and grow into adult plants


1
1

1

1

1
1


Any 4


4m



TOTAL
20M











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