Teknik Menjawab Soalan PSPM Biologi

•Electron Transport Chain






+
Proton/ HYDROGEN ION (H ) are pumped

from matrix into intermembrane space of


MITOCHONDRIA.











•Fermentation






Occur when NO OXYGEN / ABSENT OF


OXYGEN NOT insufficient of oxygen.

(a) In glycolysis, substrate level
phosphorylation through CALCULATION OF 38 ATP

(i) Oxidation of Glyceraldehyde-3-
phosphate (3C) to pyruvate (3C) FROM 1 MOLECULE OF
= _2_x_2_ ATP
= ___4___ ATP GLUCOSE

+
(ii) Oxidation of 2(NADH + H ) in
the electron transport chain
(oxidative phosphorylation)
= _2_x_3_ ATP
= ___6___ ATP (b) In Krebs cycle (including link
reaction), for 1 pyruvate
(iii) Total ATP yield
= __10___ ATP (i) From conversion of 1 GTP
(substrate level
Minus; phosphorylation)
(iv) ATP used in the = __1__ ATP
phosphorylation of glucose (6C) +
to fructose-1,6-bisphosphate (ii) Oxidation of 4 (NADH+H ) in
the electron transport chain.
(6C) oxidative phosphorylation yield
= ___2___ ATP = _4_x_3_ ATP
= ___12__ ATP
(v) Net ATP yield
= ___8___ ATP (iii) Oxidation of 1 FADH2 in the
electron transport chain
oxidative phosphorylation yield
= _1_x_2_ ATP
= ___2___ ATP

(iv) Total ATP molecule for each
pyruvate molecule
= ___15__ ATP


Total ATP molecule for each glucose (6C) molecule = _2_x_15_ ATP = 30 ATP
Overall ATP production from the oxidation of each glucose molecule in aerobic
respiration
= 38 ATP

RESPIRATION TYPES COMPARISON






Aerobic respiration Anaerobic respiration



Oxygen is present (a) Oxygen is absent


(b) complete oxidation of glucose Incomplete oxidation of glucose



(c) products of respiration is Products of respiration ;



CO , H O, and energy Lactic acid and energy (in muscle cells) or
2
2
ethanol, carbon dioxide and energy (in yeast)


38 molecules of ATP are generated (d) 2 molecules of ATP are generated



The process takes place in mitochondria (e) the process takes place in cytoplasm

TOPIC 6




PHOTOSYNTHESIS

1. They should use the term photolysis of water and they should be able to differentiate between


NADH and NADPH




2. Understand the process of forming ATP and NADPH only happen during daytime because this


process involves light/sunlight to excite electron in thylakoid membrane.

Fahami proses penghasilan ATP dan NADPH hanya terhasil pada waktu siang kerana proses ini memerlukan cahaya matahari untuk

menguja electron dalam thylakoid membrane




3.Please make sure you are not answering differences of C3, C4 and CAM in a table form. Please


make sure you really write the correct reciprocal differences.


Pastikan jawapan perbezaan antara C3, C4 dan CAM pathway tidak dijawab dalam bentuk jadual




4.Students should be able to answer the formation of phosphoglycolate and 3-phosphoglycerate

during photorespiration instead of the normal occurance due to low level of carbon dioxide.


Calon dapat menyatakan apa itu fotorespirasi namun tiada calon yang menyatakan pembentukan fosfoglikolate dan 3-fosfogliserate

5. Students misconceptualize that photosynthesis does not occur at night. It is


suppose that only light dependant reaction does not occur at night.


Kebanyakkan pelajar menyatakan fotosintesis tidak boleh berlaku pada waktu malam, sedangkan soalan tersebut


hanyalah merujuk kepada tindakbalas cahaya sahaja.





6. Make sure your answer on benefit of plants having PEP carboxylase is because it


has higher affinity towards CO 2.


Pastikan memberikan jawapan yang tepat bagi faedah tumbuhan yang mempunyai PEP carboxylase (has higher


affinity towards CO / bukan has high affinity towards CO )
2
2


7. Please differentiate carefully between hydrolysis of water and photolysis of water.


prefer to highlight it like this : photosynthesis involved photolysis of water where



water molecules is split into proton, electron and oxygen during non-cyclic


photophosphorylation) ( no need to mention hydrolysis of water)


Dapat membezakan proses hydrolysis of water dengan photolysis of water



Topic 7: Gaseous Exchange and Its Control





• Describe three ways of carbon dioxide transport from respiring


tissues to lungs








Tips ! Imagine haemoglobin

structure. Adaptation means
that the structure fits its

function.








Significance
Adaptation

Has biconcave shape to increase the surface area for effective gaseous exchange



No nucleus to provide more space for haemoglobin storage


Has elastic membrane to change the shape easily / ease the movement in blood

capillary

No mitochondria to prevent the transported O2 be consumed

TOPIC 7








Gaseous Exchange and





Its Control

Topic 7: Gaseous Exchange and Its Control





Compare oxygen dissociation curve


of haemoglobin and myoglobin











• Axis label


• Position of both curve (label

each curve correctly)



• Shape of both curve
(sigmoid for haemoglobin &


hyperbolic for myoglobin)










Remember ! Myoglobin Greater Affinity (towards O ) Shifted Left –
2
My Grandpa Always Smile Lovingly

Topic 7: Gaseous Exchange and Its Control






Analyse the effect of the changes in

partial pressure of carbon dioxide

towards oxygen dissociation curve


(Bohr effect)




• Axis label



• Position of both curve
(label each)



• Shape of both curve

(sigmoid for both)








Remember !

Bohr effect Lower Affinity (towards O ) Shifted Right –
2
Ben Laden Always Smile Radiantly

Topic 7: Gaseous Exchange and Its Control










Explain the role of chemoreceptors in controlling the rate of normal breathing






3 main components involved in controlling mechanisms







3. Effectors
1. Receptors
2. Control Centre
(diaphragm &
(carotid and aortic (inspiratory centre) external intercostal


bodies)
muscles)







2 keywords that usually used

1. Stimulate (inspiration)

2. Inhibit (expiration)

Topic 7: Gaseous Make sure to use the accurate terms in





Exchange and your explanation




Its Control Guard cell (not stomata)





e.g. Water potential in the guard cell decrease

Water potential in the stomata decrease


Glucose (not sugar)


Explain regulation of the stomatal opening
and closing based on starch-sugar hypothesis e.g. Phosphorylase catalyse the conversion of glucose to starch


Phosphorylase catalyse the conversion of sugar to starch


Describe the movement of water precisely



e.g. Water diffuse out by osmosis from guard cell into subsidiary cell

Water diffuse out

TOPIC 8








TRANSPORT SYSTEM

Students should be able to name cardiac cycle correctly with proper spelling.

Pelajar harus dapat menamakan kardiak dengan betul dengan ejaan yang betul.




Students should be able to differentiate between systole and diastole accurately when answering questions. Make sure the
spelling is also correct.

Fahami konsep systole dan diastole dengan tepat. Pastikan ejaan scientific term dengan betul seperti systole, diastole




Students should be well verse with the Pressure Flow Hypothesis in describing the flow of nutrients produced during

photosynthesis and its storage

Pastikan dapat menyatakan jenis hipotesis yang terlibat dalam pengangkutan sucrose dalam tumbuhan dengan tepat iaitu Pressure Flow

Hypothesis



When explaining water movement from xylem to phloem and vice versa, student should include explanation using the

difference of osmotic pressure or the difference of concentration gradient.

Fahami konsep pergerakan air dengan tepat dari xylem ke phloem atau sebaliknya kerana kewujudan kecerunan kepekatan atau kewujudan daya
keupayaan air (water potential) pada kawasan tertentu




Students should bear in mind that sucrose which arrive at sink cell is converted to starch or being stored as

energy

Pelajar sepatutnya menerangkan dengan jelas apa yang berlaku pada sucrose yang telah diangkut ke dalam di sink cell iaitu ianya disimpan

sebagai sumber tenaga atau ditukarkan kepada kanji sekiranya tidak digunakan

Transport



system:



Cardiac



Cycle

Transport



System in



Plant

TOPIC 9






HOMEOSTASIS










9.1 Concept of Homeostasis



9.2 Negative Feedback Mechanism



9.3 Human Homeostatic Organ : Structure & Function

of Kidney

OVERVIEW OF HOMEOSTASIS

OVERVIEW OF HOMEOSTASIS









9.1 Concept of Homeostasis 9.2 Negative Feedback Mechanism

9.2 Negative Feedback Mechanism

9.3 Structure Of A Kidney










































Functional unit of kidney :

THE NEPHRON






**Check spelling for Bowman capsule & differentiate the label of glomerulus & bowman capsule

9.3 FUNCTION OF




NEPHRONE : URINE




FORMATION

Urine formation :










(b) reabsorption & (c) Countercurrent


(a) ultrafiltration secretion multiplier mechanism

Regulation of water

• Urine formation.


1. Why glucose is absence in the urine?


ALL / 100% glucose is reabsorbed at proximal convoluted tubule.







2. Due to high level of alcohol in the blood, an alcoholic person will suffer

from frequent urination. Explain briefly this condition.



LESS secretion ADH


LESS water is reabsorbed at distal convoluted tubule

⚫ADH (anti diuretic hormone) = vasopressin

⚫INCREASE permeability of CD & DCT to water

⚫Diuretics → chemicals that increase volume of urine


⚫Eg: alcohol (less secretion of ADH)

⚫Eg: caffeine (inhibits Na reabsorption)
+






**wine / alcohol cause less secretion of ADH not inhibit secretion of ADH

TOPIC 10








COORDINATION

Describe how the axon membrane resting potential is established




1. In unstimulated neuron, sodium-potassium pump is activated.
+
• For every 3 sodium ions (Na ) pumped to the outside, 2 potassium
+
ions (K ) is pumped into the axon.
• By active transport against their concentration gradient.
+
• Causing sodium ion (Na ) concentration is higher outside the axon
• And potassium ion (K ) concentration is higher inside the axon
+

+
2. Axon membrane is less permeable to sodium ion (Na ) but more
+
permeable to potassium ion (K ).
• This cause potassium ion is able to diffuse outward via potassium


• channel
These diffusions cannot reach equilibrium because the sodium
potassium gradient is maintained by sodium potassium pump

3. In axon, there are many anions that is too large to diffuse out
• Causes the electrical charge in axon becomes relatively more


negative than outside
• This electrochemical gradient creates an electrical potential across


• the axon membrane
Potential difference across the membrane is about -70mV
• Membrane is in resting potential
• Since the inner membrane is negatively charged during resting


potential, membrane is in polarized state

Explain the propagation of action potential along the axon of neuron



Depolarisation
● - Stimulus causes sodium potassium pump to stop functioning
● When a stimulus depolarizes the membrane, some gated sodium

ion channels open allowing more Na to diffuse into the axon.
+
● Causing the charges within the axon becomes less negative than

the resting potential (closer to zero)
Rising phase of action potential


● If the stimulus is strong enough, depolarisation reaches threshold
level (-55mV), a nerve impulse or action potential is generated
● Local circuit is produced
● The affected area of the membrane become positively charged
● The diffusion of Na in the affected area, induce the opening of
+
voltage-gated Na channel in the adjacent region
+
● This causes the next voltage-gated Na channel in the region to
+
open

● Allowing Na to diffuse in that area causing that region to be
+
depolarized

● Once generated, action potentialis self propagating

● Action potential is regeneratedrepeatedly along the axon
● Action potential is a wave of depolarization that propagates until

end of axon in one direction
● Action potential is prevented from turning backward by refractory
period

Mechanism of impulse transmission across synapse



1.An action potential arrive at synaptic knob, depolarising the presynaptic

membrane

2+
2. The depolarization, open voltage-gated calcium ion (Ca ) channel in the
presynaptic membrane, triggering an influx of Ca 2+






3. Ca 2+ stimulates synaptic vesicles to move towards presynaptic
membrane & fuse with it





- The vesicles release neurotransmitters to the synaptic cleft by

exocytosis


- Neurotransmitters diffuse across synaptic cleft & move towards

postsynaptic membrane



4. It binds to the receptor on the postsynaptic membrane, Causing
+
the ligand-gated Na channel to open



5. Allow Na from extracellular fluid diffuse into postsynaptic neuron
+
and cause Postsynaptic membrane depolarize (EPSP).

- If depolarization reaches threshold level, impulse / action

potential is generated in the next neuron

Compare Impulse Transmission Along Axon & At Synapse





At synapse Along the axon



Occurs between 2 neurons / between Occurs along axon of a single

presynaptic neuron & potsynaptic neuron neuron


Impulse is chemically transmitted Impulse is electrically transmitted






Involves neurotransmitters No neurotransmitters involved




Speed of impulse transmission is Speed of impulse transmission is


relatively slower relatively faster


Involves the diffusion of Ca 2+ into Does not involves the diffusion of
the presynaptic neuron Ca 2+ into axon


Involves ligand gated ion channels Does not involves ligand gated ion channels but

+
+
involves voltage gated Na and K ion channels
81

Mechanism of Cocaine At Synapse




1. Cocaine blocks the reuptake of dopamine into

presynaptic neuron by binding to transporter protein




2. Dopamine accumulates within the synaptic cleft and

continuously bind to the receptor on the postsynaptic

membrane



3. Continuous depolarisation occurs and impulse is

transmitted repeatedly causes overstimulation of the

postsynaptic membrane


4. To maintain homeostasis, body response by:


➢ reduce synthesis of dopamine

➢ decrease the number of receptors on postsynaptic

membrane

5. By taking in more cocaine, less dopamine is produced

& less number of receptors on postsynaptic membrane
82

Describe the events that occur when a resting skeletal muscle is stimulated by a motor

neuron

At neuromuscular junction

● Action potential reaches at the axon terminal
● voltage-gated calcium ion (Ca ) channel open
2+
● Ca 2+ diffuse into axon terminal

● Ca 2+ stimulates synaptic vesicles to move towards presynaptic
membrane & fuse with it
● Acetylcholines (Ach) are released into synaptic cleft
● By exocytosis
● Acetylcholines bind to the receptor proteins on the sarcolemma
+
● Causes the ligand gated Na channels to open
+
● Na diffuse into sarcoplasm
● Depolarisation occur (known as end plate potential (EPP) )
● If depolarization exceeds threshold level, action potential is

generated

At Muscle



● Action potential spreads along the sarcolemma via T tubule
● Stimulate sarcoplasmic reticulum to release calcium ion into

sarcoplasm
● When Ca 2+ is released, it binds to troponin & changes its
conformation
● Tropomyosin move away to expos the myosin binding site on actin
● ATPase at myosin head is activated to hydrolyze ATP into

ADP & P i
● Energy released change myosin into high energy

configuration

Describe the events that occur when a resting skeletal muscle is stimulated by a motor

neuron


At Muscle




● Myosin head binds with actin to form

cross bridge

● Phosphate is released from myosin head

● Myosin head bends 45 0

● As it bend, thin filament is pulled towards the

middle part of sarcomere (power stroke)

● ADP is released

● A new ATP molecules attaches to the myosin

head causes cross bridges detach

● If sufficient Ca 2+ are present, power stroke

repeats

● During contraction, thin filaments slide past

the thick filaments

● Which causes the skeletal muscle cell to

shortens

Mechanism of Gene Activation

Testosterone travels through the blood and diffuse into

the cells




Testosterone bind to a receptor protein in the cytoplasm
/ nucleus





To form hormone-receptor complex




The hormone-receptor complex

moves towards the nucleus




Bind to a specific regulatory site on DNA




Stimulate expression of specific gene




• Steroid hormones is lipid soluble / Transcription occurs ~ mRNA is synthesised
hydrophobic

• Can easily diffuse across the cell membrane

• Eg: testosterone mRNA enters the cytoplasm
mRNA is translated into specific proteins


85

Mechanism of Cyclic AMP Activation Non-steroid hormone (eg: insulin/glucagon/adrenaline)

binds to a specific receptor protein on the membrane of

target cell (eg: liver cell, muscle cell)




To form hormone-receptor complex (Hormone act as first

messenger)




This binding activates G-protein in the plasma membrane



Activated G-protein releases GDP




A new GTP binds to G protein, change its conformation




Which enable G-protein to bind with adenylyl cyclase





Which activates adenylyl cyclase to hydrolyse ATP to cAMP

(and PP)
i
• Non-steroid / hormone or amino acid based hormone cAMP act as second messenger inside the cell which activates

• Insoluble in lipid protein Kinase A that catalyzes phosphorylation process

• Cannot diffuse through the cell membrane
• Eg: insulin / epinephrine / glucagon Eg : In skeletal muscle, glucagon stimulate the breakdown of

glycogen to glucose
86

Differences between cAMP and gene

activation




cAMP activation Gene activation cAMP activation Gene activation

mechanism mechanism mechanism mechanism


Involve non-steroid Involve steroid hormones Transcription and Transcription and

hormones translation do not translation do occurs


Hormones are Hormones are lipid occur

insoluble in lipid and soluble and can enter Produce faster Produce relatively slower
cannot enter the cell into target cell response response


Hormones bind to the Hormones bind to the Effects of hormones is Effects of hormones is

receptor found on cell receptor in cytoplasm or short term (ranging long term (ranging from a

membrane nucleus from a few minutes to few hours to a few days)


Hormones do not Hormones activate a a few hours)

activate the gene specific gene Involve a second No second messenger is

messenger (cAMP) in involved because

the cell hormones can enter



87

Phytochrome & Its Role
































∙ Phytochrome is a blue-green


pigment in leaves


∙ Act as photoreceptor


∙ Absorb mostly red light



∙ Role : control flowering &

germination







88

Role of phytochromes in controlling



flowering





∙ Phytochrome is the main photoreceptor

for photoperiodism.



∙ Exists in two interconvertible forms (P R

and P FR)




∙ P inactive form while P FR is the active
R
form




∙ Plant synthesizes phytochrome in its

inactive form P R



∙ During the day, P absorbs the red light
R
and changes rapidly to P .
FR










89

Role of phytochromes in controlling flowering






∙ During the night, P FR ∙


spontaneously converted back to But in short day plants, high level
of P
inhibits the production of
FR
P Slowly florigen
R.
∙ Or converted rapidly to P FR

when exposed to far red light. ∙ Therefore inhibits flowering of

short day plant
∙ In long day plant, more P is
R
converted into P FR due to longer ∙ But when exposed to a short day

light exposure period of daylight,less P is
R
converted to P FR.

∙ In long day plants, high level of ∙ Low level of P stimulate the

FR
P FR stimulate the production of production of florigen hormone
florigen hormone
∙ which stimulate flowering in short

∙ which stimulate flowering in long day plants


day plants.







90

91

TOPIC 11













IMMUNITY

Innate and adaptive immunity are type of immunity



Innate- not specific




Adaptive –specific



Antigen-antibody interaction – neutralization, opsonization dan activation of

compliment system and pore formation



Immune response- humoral and cell mediated immune response



Keywords for this topic:



Antigen-antibody complex, class I or Class II MHC antigen complex, proliferate,


differentiate, secrete



Please remember several example of vaccines inside the notes

immunity





Cell mediated immune response


- Macrophage engulf antigen by phagocytosis

- fragments of antigen is displayed on the cell surface

together with a class II MHC

- Formed class II MHC- antigen complex , macrophage

known as antigen presenting cell (APC)

- APC secrete IL-1 which activates TH cell secrete IL-2

- Antigen also infected body cells, fragment of antigen is

displayed on the cell surface together with class I MHC

- Formed class I MHC-antigen complex
- Tc cell binds to the complex on infected cell

- TH cell secrete IL-2 that activated the Tc cell to proliferate

and diffentiate into activated Tc clone and memory Tc clone
- IL-2 stimulate activated Tc cell to release perforin and

granzymes which form pores in the infected cell’s membrane

- The cell lyse

Primary and secondary immune response







Primary immune response Secondary immune response


first exposure –lag phase no

antibody is produce -memory B cell recognize the same
antigen faster
-takes 3 to 6 days for antibody to

increase -memory B cell proliferate and
differentiate rapidly into plasma cell to
-because B cell takes time to

proliferate and differentiate into produce antibody
plasma cell and memory B cell -the response is faster, concentration


-low concentration of antibodies antibodies is higher
are produce, mainly IgM is

produced -Antibody produce mainly IgG

- Antibodies increases and reach -memory B cell able to recognize

peak in ~10 days before declining antigen for longer period of time/
long lasting
-the response is short lived