Pre Spm Quick Revision

8/7/2019 Pre Spm Quick Revision

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PRE SPM QUICK REVISION

CHAPTER 3

1. Type of substances moving through the

diff.parts of the plasma membrane.

a) Phospoholipids bilayer small lipidsoluble molecules, charged ions,

gases

Process involved : simple diffusion

b) Carrier protein large water solublemolecules e.g glucose, amino acids

Process involved : facilitated diffusion

c) Carrier protein ions

Process involved: active transport

(When explain any process, make sure

to mention the

diff. in concentration and end up the

sentence with

the process involved)

(When discuss any process, do not

write like this : e.g facilitated

diffusion moves from high

concentration area to low

concentration area, but always write ,

in facilitated diffusion substances

move from high concentration area to

low concentration area.)

2. Metabolic / respiratory poison inhibitsthe production of ATP energy, therefore,

inhibits active transport. Denaturing of

protein can cause destruction to the carrier

and pore protein, therefore, inhibits

facilitated and active transport.

3. 30% sucrose solution is hypertonic / Distilledwater is hypotonic towards the cell sap

(plant cell) / cytoplasma (animal cell)

4. Hypertonic / hypotonic:- Water moleculesdiffuses out / into the cell sap (plant cell) /

cytoplasma (animal cell) through the plasma

membrane by osmosis

5. Hypertonic:- Plant cell becomes flaccid dueto plasmolysis / animal cell -crenates.

Hypotonic:- Plant cell becomes turgid /

animal cell burst (haemolysis)

6. When you draw flaccid cell, make sure thecell still has two layers (cell wall), the

vacuole is smaller, the plasma

membraneis pulled away from the cell

wall. Turgid cell the vacuole must be

bigger than normal

7. Movement of water into root hair cells:-Soil water is hypotonic towards . //

Excess fertilizers causes soil water to

become hypertonic towards

CHAPTER 4

1. DNA - Structure: Made up oftwopolynucleotides. Double helix.

Function: Carries / stores all genetic

information

RNA Structure: Made up ofone

polynucleotide. Single chain. Function:

Carries genetic information on protein

synthesis

2. DNA /RNA :- Elements:- Carbon,

Hydrogen, Oxygen, Phosphorus,Nitrogen. Components:- Phosphate

group, pentose sugar, nitrogenous

base. Basic Unit:- Nucleotide

3.


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4. Points to remember in explaining theformation ofextracellular enzymes:-

a) DNA unwinds, exposing the codeson protein synthesis

b) Protein from the ribosomes move tothe membrane of RER. The

membrane buds off forming

transport vesicles which moves

towards Golgi Apparatus and fuses

with the membrane of GA.

c) GA modifies, sorts and packagesthe proteins and the membrane buds

off forming secretory vescicleswhich moves towards Plasma

membrane and fuses with the

membrane to release the enzymes.

5. Lock and Key Hypothesis:- Whenname of enzyme is given, make sure

to specify the explanation. E.g If

Lactase is given.

a) Lactose binds at the active site ofLactase to form Lactose- lactase

complex. Hydrolysis occurs which

breaks lactose into glucose and

galactose which later live the active

site living lactase unchanged.

6. Relating temp. and enzyme

activity:-

Any increase towards optimum more heat

which increases kinetic energy of both

enzyme and substrate molecules, increases

the collision so more chances of the

substrate molecules to come into

contact with enzymes molecules.

7. Relating pH and enzyme activity:-

Changes in pH, changes the charges on

the active site and surface of substrate.

Active sites and subtrates must have diff.

charges. Low pH causes more H+

attach to the active sites. High pHcauses more OH- attach to the active

site.

CHAPTER 5

1. Cell cycle:- the period from the timea cell is produced until the time the cell

completes a division

2. G1:- Proteins and new organellesproduce. S phase:- DNA

undergoes replication forming identical

sister chromatids. G2:- More proteins

and organelles produced

3. Chromosomal Behaviour

Metaphase :-Align atequator /metaphaseplate

Anaphase:-Move toopposite poles

Mitosis

Sisterchromatidsalign ..

Centromeredivides.SisterchromatidsseparateDaughter

First Class protein Second Classprotein

Contain allessential a.a

Does not contain allessential a.a

Animal protein Plant protein

Essential A.A Non essential A.A

Cant besynthesized by bodycells

Can be synthesized

Saturated Fats Unsaturated FatsSolid in roomtemp.

Liquid in roomtemp.

No double bond

btwn carbon atom.

Double bond is

still presence


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chromosomesmove.

Meiosis 1

Bivalentalignrandomly

Centromeredoes notdivideBivalentsseparate

Sisterchromatidsmove .

Meiosis 11

Sisterchromatidsalign ..

Centromeredivides.SisterchromatidsseparateDaughterchromosomesmove.

4. Points to remember in explainingTissue Culture:

a) Remove meristematic tissues(explants) from a desirable plant

b) Place it in sterile cultures medium

c) Incubate at 37 C for 3 weeks untilcallus is formed

d) Cut callus into smaller pieces and putevery cut into sterile growth

hormones to form embryo andlater plantlets

e) Plantlets taken to soil

5. Tissue Culture

Advantage Disadvantage

Inherit desirable

characteristics

Large quantity

produced in shorter

time

No variation

Having the sameresistance towards

certain disease-

shorter life span

6. Points to remember in explaining

animal cloning

a) Somatic cells from desirable animal

removed

b) Unfertilised ovum from a donor isremoved and its nucleus is also

removed

c) Fusion between the somatic cell andthe ovum without nucleus

d) The embryo is implanted to thesurrogate mother.

CHAPTER 6

1.Balanced diet:- a diet containing all

the seven

classes of food in the correct

proportion

2. Diet for different groups:-

Pregnant ladies More protein-fetus

tissue formation

More caliums and

phosphorus bone

dev. Of fetus

More folic acid

and ferum more

fetus RBC formationInfants and children More calcium and

phosphorus- teeth

and bone formation

More protein

enhance growthAtheletes More

carbohydrates

More protein-

muscle formationMore sodium - to

prevent muscle

cramp

More vitamins and

minerals- maintain

healthy


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3. Symptoms ofkwashiorkor:-distended stomach due

to water retention

4. Explaining digestion, e.g:-

In the mouth, starch is digested /

hydrolysed into maltose by maltase in

the presence of water molecules

5. Digestion along the alimentary canal.

Organ Digestion Enzyme

Mouth Starch into

maltose

Salivary

amylase

Stomach Protein into

polypeptide

Pepsin

Duodenu

m

Polypeptide into

peptide

Starch into

maltose

Tiny droplets of

lipids into fatty

acids and glycerol

Trypsin

Pancrea

tic

amylase

Lipase

Ileum Peptide into

amino acids

Maltose into

glucose

Sucrose into

glucose

Lactose into

Glucose

Erepsin

Maltase

Sucrase

Lactase

6. Bile produced by liver and stored ingall bladder. Is used to emulsify lipids

into tiny droplets of lipids.

7. No enzyme produced by duodenum.The enzymes

in duodenum are produced by

pancreas

8. If any enzyme failed to be produced,remember

that digestion still occurs but at

slower rate//

incompletely. So, dont write, no

digestion takes

place.

9. Structural adaptation of ileum

a) Long and forms folded structure-increase surface area for more

absorption and digestion

b) Contains numerous number of villi-increase surface area for amore

absorption of nutrients

10. Structural adaptation of villi

a) Long projection- increase surface area-

more absorption of nutrients

b) Have numerous of microvilli ot the

surface- increase surface area

c) Wall thin-one cell thick- rapidabsorption of nutrients

d) Contain (not covered) network ofblood capillaries more transport of

glucose, a.a, water soluble vit. And

minerals

e) Contain a lacteal - transport of lipidsoluble vitamins and fatty acids and

glycerol

11. Glucose, a.a, water soluble vitamins andminerals are transported to liver

through HEPATIC PORTAL VEIN.


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REMEMBER:- Therefore, this vein

contains higher concentration of those

nutrients than other veins.

12. Fatty acids , glycerol and lipid solublevitamins are transported out from the villi

by lymphatic vessels to thoracic duct

and is drained into left subclavian

vein.

13. Assimilation in the liver

Glucose Excess converted by insulin

into glycogenUsed by the liver cells for

cellular respiration

Amino

acids

Excess- converted into urea

(deamination) to be

transported to kidney for

excretion.

Used by liver cells to

produce new protoplasm

Synthesis plasma protein

14. Assimilationin other body cells

Glucose Excess converted by insulin

into glycogen and stored in

muscles

Used by the cells for cellular

respirationAmino

acidsUsed by cells to produce new

protoplasm

, repair injured tissues,

synthesize enzymes and

hormones and plasma

membraneLipids Phospholipids used by cells to

produce plasma membrane

15. Points to remember rin explainingdigestion in RUMINANTS

a) Partially chewed food is taken torumen

b) Cellulose is digested by cellulosewhich is produced by symbiotic

microorganisms ( WHY SYMBIOTIC

????) - The microbes use a part

of digested food.

c) Partially digested food enters thereticulum for further digestion

( similar to the one in the rumen) and

cud is formed

d) The cud is regurgitated into themouth.

e) The cud is reswallowed and taken tothe omasum where large particles

of food is broken into smaller parts.

Water from the food is removed here

f) The food particles move to theabomasums true stomach .

(WHY ???? - It contains gastric

juices like our stomach to digest

proteins and other substances.)

g) The digested food then taken to smallintestine to be absorbed

16. Points to remember rin explainingdigestion in RODENTS

a) Cellulose is digested in its largecaecum

b) Soft faeces are produced at nightand are eaten to enable the animal to

absorb the products of digestion -

causing the second faeces to

become harder.


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17. COMPARING THE DIGESTIVE SYSTEM OFHUMAN, RUMINANTS AND RODENTS

Similarities

All the three have stomach where

digestion of protein occurs

All the three cannot produce their own

cellulase

Human Rumina

nt

Rodent

No.ofstomach

chambers

1 4 1

Cellulase

producing

bacteria

No Presenc

e

Presenc

e

Place for

digestion

of

cellulose

None Rumen

&

reticulu

m

Caecum

Regurgitat

ion

None Occurs None

Size of

caecum

Small Small Large

18. Nutrient deficiency in plants

NitrogenChlorosis - synthesized ofchlorophyll is inhibited

Stunted growthMagnesiu

m

Chlorosis

Phosphor

us

Poor growth

Potassiu Reduce protein synthesis-

m poor growth

19. Structural adaptation of a LEAF for

optimum rate of photosynthesis

Waxy layer on top

of epidermal

tissues

Prevent higher rate

of transpiration

Leaves are

arranged in an

arrangement called

leaf mosaic

Leaves are spread

out for optimum

exposure to sunlight

Thin lamina Allows rapid

diffusion of gases

involved inphotosynthesis

No chloroplast in

epidermal tissue

(transparent)

Allow penetration of

maximum sunlight

Contains vascular

tissues-xylem and

phloem

Transport of water

and products of

photosynthesis

Pallisade

mesophyll cellsare closely

packed and

contain abundant

of chloroplasts

Maximum amount

of light receive

Spongy

mesophyll cells

are loosely

packed and

contain abundant

of chloroplast

Allow the presence

of large air space

for exchange of

gases to occur

20. Adaptation of plants in different

habitats

Land plants More stomata at the

lower epidermal


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tissues- to

prevent excessive

lost of water

Floating plants More stomata on

the upper

epidermis

Aquatic plants Chloroplasts found

all over the surface

(therefore, the

whole leaves and

stem is green) as

low intensity of light

in water

Desert plant Very few stomata

and some are

sunken stomata-

embedded in the

leaves to reduce

water lost

Chloroplasts found

mostly on stems


light reaction

a) Occurs in Grana

b) Chlorophyll captures light energywhich excites the electron in the

chlorophyll to leave the chlorophyll

c) Light energy splits water moleculesinto H+ and OH- (photolysis)

d) H+ receive electron to form H atoms

e) OH- releases electron to form hydroxyl

group

f) Hydroxyl group binds with otherhydroxyl group to form water

molecules and oxygen


dark reaction

a) Occurs in stroma

b) Hydrogen atom binds with carbondioxide to form glucose (reduction)

23. Comparing light and dark reaction

Light reaction Dark reaction

Grana Stroma

Requires light

energy, waterRequires carbon

dioxide

Does not requirelight energy

Produces water and

oxygen

Produces glucose

and water

Forms hydrogen

atoms

Uses hydrogen

atoms

Occurs only in the

presence on light

Occurs with and

without light

24. How Greenhouse aids in ensuring cropproduction takes place throughout the

year

Controlling Carbon

dioxide

concentration

Burning paraffin

to ensure

continuous supply

of CO2

Light intensity The use of glass

allows penetration

of light. When light

intensity is low- use

artificial

lighting.When light

intensity is too high

- use shades or

light reflector

Temperature Always warm inside

as heat cant


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escape through the

glass. If too hot,

use heat regulator,

shades and

ventilation

Water Automatic sprinkler

25. REMEMBER: In highly industrial areas,photosynthesis might be affected due to

dust and smoke covering the stomata ,

hence inhibits diffusion of carbon

dioxide.

26. The importance of photosynthesis is toensure continuous existence of life

on earth as photosynthesis supplies

oxygen to living organisms

27. Food preservation

Drying Food placed under

hot sun water in

the food

evaporated food

dehydrated- inhibitgrowth of microbes

Pickling sugar and

salt solution

Vinegar

The solution is

hypertonic

towards , water

diffuses out by

osmosis. Food

dehydrated- inhibit

growth of microbes

Vinegar- acid

medium not

suitable formicrobes to live

Pasteurisation Milk is heated:-63 C

for 30 minutes//

72 C for 15

seconds followed

by rapid cooling

Fermentation Use yeast which

produces ethanol

inhibit the

activity of

microbes

CHAPTER 7

1. Aerobic and Anaerobic respiration

Aerobic Anaerobic

Definati

on

Oxidation

of glucose

completely

Breakdown of

glucose

incompletely

Substrat

es

Glucose &

oxygen

Glucose

Product

s

Carbon

dioxide,

water, 38

ATP

Human:-

Lactic acid, 2

ATP

Yeast:-

Ethanol, CO2

Sites Mitochondri

a

Cytoplasma

2. Respiratory surface of different

organisms

Human Alveli

Frogs Lungs, Skin

Fish Lamella

Insect Tracheol

Ameoba Plasma membrane


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3. General Adaptation of Respiratory

surface

Moist surface Allow oxygen to

dissolve before

diffusion occurs

Thin wall Allow rapid

diffusion of gases

Numerous in

number- alveoli,

tracheal and lamella

Large surface area

for more exchange

of gases to occur

Alveoli and frog

lungs covered

with network of

blood capillaries

Gills contain

numerous bloodcapillaries

Allow more

transport of gases

4. REMEMBER:- Tracheols are embeddedin body

tissues. Therefore, no transport of

gases required

5. NOTE:- Frog lungs : Unlike human

lungs , there is

no alveolus. Exchange of gases

occurs through the wall of the lungs.

Therefore, the wall is moist, thin and

covered with blood capillaries

6. COUNTERCURRENT EXCHANGE :- toallow efficiency of the gases exchange at

the respiratory surface of fish. The

mechanism MAXIMIZES THE OXYGEN

TRANSFER BECAUSE AS WATER

FLOWS OVER THE GILLS IN ONE

DIRECTION, THE BLOOD FLOWS IN

THE OPPOSITE DIRECTION.

7. Oxygen is transported to body tissues bybinding with haemoglobin in RBC to

form oxyhaemoglobin.

8. Carbon dioxide is transported in three

ways:-

a) In a form ofcarbonic acid bydissolving in blood plasma.

b) In a form ofcarbaminohaemoglobinby binding with haemoglobin

c) In a form ofbicarbonate ions

9. J-tube experiment:-

a) The tube is immersed in potassiumhydroxidefirst as the solution only

absorb carbon dioxide.

b) Later the tube is immersed inpotassium pyrogallate solution to

absorb oxygen

c) Do not immerse the tube inpotassium pyrogallate first, as it

can absorb both carbon dioxide

and oxygen. Therefore, unable to

determine the concentration of both

gases.


regulatory mechanism of blood pH

a) During vigorous exercise, moreCO2 produced,

thus blood pH becomes lower

than normal

b) Detected by peripheralchemoreceptor ( at the

carotid arteries and arch of aorta)

and central


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chemoreceptor ( at the medulla

oblongata)

c) Receptors generate impulses whichare sent to

the breathing center at the

medulla oblongata

d) Breathing centre interprate theinformation

and produces appropriate

responses

e) Impulses are then sent torespiratory

muscles(intercostals and diaphragm

muscles)

and cardiac muscles.

f) Increase the contraction of thethree muscles

g) Increase breathing , ventilation

and heart beat

rate

h) Remove excess carbon dioxide,return the

blood pH to normal

11. Points to remember in explaining the

intake of oxygen by plants for

respiration

a) When stomata opens, oxygen

diffuses in and dissolves in water

found in the air spaces

b) As oxygen in the air space is higher in

concentration than in the cells,

oxygen diffuses into the cells,

12. COMPENSATION POINT: The rate ofcarbon dioxide production is equal to the

rate of carbon dioxide consumption. The

rate ofphotosynthesis is equal to the

rate ofrespiration.

13. REMEMBER:- For plants to grow, therate of photosynthesis must always

be HIGHER than the rate of

respiration as excess sugar can be

used for growth and other important

living processes.

CHAPTER 8.

1. Problems faced by mangrove plants

a) Muddy soft soil (water loggedcondition) easy to collapse

b) Exposed to strong winds easy to

collapse

c) Exposed to high intensities of sunlight

higher

rate of transpiration

d) Surrounded by sea water high

concentration of

salt

2. Structural adaptation of mangrove plants

and therefore no other plants can grow in

mangrove swamp

a) Long cable root provide

support

b) Aerial roots (pneumatophores)-allowing gases exchange during low

tide

c) Small leaves with sunken

stomata reduce transpiration

d) Hydathodes (pores on thelower epidermis) remove excess salt

e) Cell sap of the root hair cell is

always hypertonic towards

surrounding water

f) Viviparous seeds germinate

while still attaching to the mother

plants increase the chances of

survival


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3. REMEMBER THE DIFFERENT TYPES OFROOT BELONG TO DIFFERENT

MANGROVE SPESIES.

4. REMEMBER THE ZONING AND BE ABLETO IDENTIFY THE ZONE IN WHICHDIFFERENT MANGROVE SPESIES

BELONG TO

5. Point to remember in explainingcolonization and succession in a

mangrove swamp

a) The physical changes that cause

succession to occur are:-

i) Soil becomes more compactand

firmer , and the river bankbecomes higher due to

accumulation ofsilt and mud which

are trapped by the root of the

mangrove plants

ii) The shore extends further to

the sea as more sediments

deposited

6. Point to remember in explaining

colonization and succession in an

abandoned pond

a) The physical changes that cause

succession to occur are:-

i) The pond becomes shallower

due to :-

- soil erosion form the

sides of the pond

- The decomposition of

dead plants

which forms organic

matters. The

organic matters settled at

the bottomof the pond.

7. REMEMBER ALL THE THREEFORMULAE IN DETERMINING A

POPULATION USING QUADRAT

SAMPLING

8. REMEMBER ALL THE FORMULA INDETERMINING A POPULATION USING

THE TECHNIQUE CAPTURE, MARK,

RELEASE, RECAPTURE.

9. Why Nitrogen cycyle is important ???

Plants cannot absorbed atmospheric

nitrogen directly. But they need nitrogen

to synthesize protein. Therefore,

nitrogen need to be converted in a

form of ammonium, nitrites or

nitrates as onlythese three can be

absorbed by plants

10. Nitrogen Cycle

a) Nitrogen fixation:-

- Lightning

- Nitrogen fixing bacteria

- Rhizobium sp. living in the root nodules ofleguminous plants . It fixes atmospheric

nitrogen into ammonium

-Nostoc sp. live freely in soil fixesatmospheric nitrogen into ammonium

b) Decomposition

Dead plants and animals are

decomposed by microorganisms to

form ammonium compound

c) Nitrification

- Oxidation of ammoniumcompound into nitrites by

Nitrosomans sp.

- Oxidation of nitrites into nitrates by Nitrobacter sp.

d) Denitrification

Denitrifying bacteria breaks down

nitrates into gases nitrogen

11. WHAT IS THE EFFECT OF DESTROYINGANY OF THE MICROBES INVOLVED IN


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NITROGEN CYCLE ON THE GROWTH

OF HERBIVORES ?????

a) If nitrogen fixing bacteria ordecomposer is killed no ammonium

can be produced, therefore, no nitrites,

no nitrates to be absorbed by plants.REMEMBER, NITRATES IS

ABSORBED TO OBTAIN NITROGEN

TO SYNTHESIZE PROTEINS IN

PLANTS. IF PLANTS ARE LACKING

OF PROTEINS, LESS PROTEIN

TRANSFERRED TO HERBIVORS-

LESS PROTEIN FOR THE

HERBIVORES TO GROW.

12.

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