Suc Biology F4 Vnotes 2017.pdf

Years in Malaysia

1957–2017

Inspiring Learning Enriching Lives

BIOLOGY

Made Easy SPM Virtual Notes

FORM

4

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CHAPTER 1

Introduction to Biology

Objective

State the aim of the experiment.

Problem statement

Pose questions about the observations made.

Hypothesis

Formulate a possible explanation or prediction based on the observations.

Variables

Identify and control the manipulated, responding and constant variables.

Materials and apparatus

List the materials and apparatus which will be used during the experiment.

Technique

State the technique involved in obtaining the results.

Procedure

• Write the instructions to carry out the experiment. • The procedures should be written using reported speech. For example, ‘Examine the slide under the microscope’ should be written as ‘The slide is examined under the microscope’. • Diagrams can be drawn to show the set-up of the experiment. They should be simple and twodimensional. The apparatus should be drawn with a clear outline and labelled accordingly.

Results

Present the results in the form of simple diagrams, charts, graphs or tables. Include calculations where necessary.

Discussion

Discuss, analyse and interpret the data obtained, then determine the relationship between the manipulated variable and responding variable.

Conclusion

Draw a conclusion based on the hypothesis given earlier. © Oxford Fajar Sdn. Bhd. (008974-T) 2017

CHAPTER 2

Cell Structure and Cell Organisation

Human cells and the adaptations to their functions

Nerve cells Have long, thin fibres called axons to conduct nerve impulses.

Red blood cells Shaped like biconcave discs and are very flexible, allowing them to move easily along the narrowest blood vessels. © Oxford Fajar Sdn. Bhd. (008974-T) 2017

Sperm cells • The tail allows the sperm to swim towards the ovum. • The head contains one set of chromosomes from the male organism.

White blood cells Can change their shape to migrate to the sites of injuries to fight infections.

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Cellular components of a plant cell plasma membrane chloroplast

3 1

nucleus

4

mitochondrion cell wall of adjacent cell vacuole

rough ER

lysosome

2 ribosome

5

smooth ER

outer membrane

Golgi apparatus

1

inner membrane nucleoplasm nucleolus

Nucleus • Controls all cellular activities. • Contains DNA which determines the characteristics of a cell.

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nuclear membrane pore in nuclear membrane © Oxford Fajar Sdn. Bhd. (008974-T) 2017

nucleus

nuclear envelope ribosomes

2

rough endoplasmic reticulum smooth endoplasmic reticulum

outer membrane

3

• Ribosomes − sites of protein synthesis • Rough endoplasmic reticulum (RER) − transports proteins made by ribosomes throughout the cell • Smooth endoplasmic reticulum (SER) − synthesises lipids and carries out detoxification of drugs and metabolic by-products

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outer membrane

inner membrane cristae matrix

inner membrane granum

Mitochondrion site of cellular respiration

5 stroma

thylakoid

Chloroplast Captures the energy of sunlight and converts light energy into chemical energy during photosynthesis.

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vesicles

Golgi apparatus Processes, packages and acts as a transport centre of carbohydrates, proteins and glycoproteins.

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Human tissues Tissues

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Functions

Epithelial tissues at the surface of the skin

Form a protective barrier against infections and mechanical injuries.

Epithelial tissues at the lining of glands, ducts and kidney tubules

Secrete substances. Example: Sweat glands in the skin secrete sweat.

Epithelial cells which line the alveoli and blood capillaries

Thin, flat and arranged in a single layer to allow for easy diffusion of respiratory gases.

Skeletal muscles

Contract and relax to produce movements of body parts.

Cardiac muscles

Contract to pump blood from the heart.

Smooth muscles

Contract and relax to produce involuntary movements.

Nerve tissues

Generate and transmit nerve impulses over long distances.

Connective tissues

Bind and support other tissues. Bone tissue – provides protection to internal organs and supports the body. Tendon – attaches muscles to bones. Blood tissue – transports nutrients and respiratory gases, fights infections and helps in blood clotting.

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Plant tissues Tissues

Functions

Epidermal tissues

Protect plants from mechanical injuries.

Ground tissues: (a) Parenchyma tissue

Stores products of photosynthesis such as sugar.

(b) Collenchyma tissue

Provides support in herbaceous plants.

(c) Sclerenchyma tissue

Supports and strengthens plants.

Meristematic tissues

Divide through mitosis to increase the number of cells.

Vascular tissues: (a) Xylem tissue

(b) Phloem tissue

• Conducts water and minerals from the roots to the shoots. • Provides support and mechanical strength to the plants. Transports organic substances from the leaves to other parts of the plant.

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CHAPTER 3

Movement of Substances across the Plasma Membrane

Structure of the membrane carbohydrate phospholipid

cholesterol

pore

carrier protein pore protein

phospholipid

hydrophilic head

hydrophobic tails

hydrophilic head

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Structure of the plasma membrane according to the fluid mosaic model: The components of the plasma membrane are not rigid but form a dynamic and fluid structure. The proteins form a mosaic pattern. Proteins and phospholipids can move sideways within the membrane.

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Movement of Substances across the CHAPTER 3 Plasma Membrane Effects of hypotonic, isotonic and hypertonic solutions on animal cells Effects of hypotonic solutions on animal cells (red blood cells)

Effects of isotonic solutions on animal cells (red blood cells)

Effects of hypertonic solutions on animal cells (red blood cells)

The solution outside the cell is less concentrated than the inside of the cell.

The solution outside the cell has the same concentration as the cytoplasm fluid within the cell.

The solution outside the cell is more concentrated than the inside of the cell.

Water diffuses into the Water diffuses into and out of the cell at cell by osmosis. equal rates.

Water diffuses out of the cell by osmosis.

The cell starts to swell The cell maintains its The cell shrinks and normal shape. and eventually burst. the plasma membrane crinkles up. This condition is known as haemolysis.

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The red blood cells are said to have crenated (crenation).

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Effects of hypotonic, isotonic and hypertonic solutions on plant cells Effects of hypotonic solutions on plant cells

Effects of isotonic solutions on plant cells

Effects of hypertonic solutions on plant cells

The solution outside the cell is less concentrated than the inside of the cell.

The solution outside the cell has the same concentration as the cytoplasm fluid within the cell.

The solution outside the cell is more concentrated than the inside of the cell.

Water diffuses into the large central vacuole by osmosis.

Water diffuses out of Water diffuses into and out of the cell at the cell by osmosis. equal rates.

The large central vacuole expands and swells up. The plasma membrane presses hard against the cell wall.

The cell maintains its normal shape.

The cell is said to be turgid.

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The vacuole and cytoplasm shrink and the plasma membrane pulls away from the cell wall. The plant cell becomes flaccid and undergoes plasmolysis.

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CHAPTER 4 Chemical ChemicalComposition Compositionofofthe theCell Cell

Medium of biochemical reactions Maintains osmotic balance

Lubrication

Transport medium

Importance of water

Provides support

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Maintains body temperature

Provides moisture

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CHAPTER 4 Chemical Composition of the Cell Carbohydrates

Monosaccharides

Disaccharides

Polysaccharides

Glucose Fructose Galactose

Maltose Sucrose Lactose

Starch Glycogen Cellulose

Glucose + glucose Glucose + fructose Glucose + galactose

condensation hydrolysis condensation hydrolysis condensation hydrolysis

maltose + water sucrose + water lactose + water

Nucleic acids DNA consists of two strands of polynucleotides twisted around each other to form a double helix. deoxyribonucleic acid (DNA)

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Structure of a nucleotide phosphate group

nitrogenous base

pentose sugar

Protein structure ply

Tertiary structure

leu val lys val

val

lau

lys lys

lya gly his ala

gly

gly ala lys

his

val lys

lys

pro

lys pro

Primary structure

Secondary structure

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Quarternary structure

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The production of extracellular enzymes 1 The nucleus contains DNA which carries the information for the synthesis of enzymes. 2 Proteins are synthesised at the ribosomes. 3 The synthesised proteins travel through the rough ER. 4 The protein departs from the rough ER in vesicles that bud off from the membranes of the rough ER. 5 These transport vesicles fuse with the Golgi apparatus. 6 The proteins are then modified in the Golgi apparatus. 7 Secretory vesicles containing these proteins bud off from the Golgi apparatus and fuse with the plasma membrane before releasing the proteins as enzymes outside the cells.

plasma membrane

protein secreted outside the cell as enzymes

7 6

5

Golgi apparatus

4

secretory vesicle transport vesicle

3

DNA

1 2

rough endoplasmic reticulum nucleus

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The uses of enzymes in daily life and industry Protease tenderises meat and removes the skin of fish. Cellulase breaks down cellulose and removes seed coats from cereal grains. It also extracts agar from seaweed. Amylase and amyglucoxidase convert starch to sugar in the making of syrup. Trypsin removes hair from animal hides.

Zymase converts sugar into ethanol.

Amylase removes starch stains on clothes.

Lipase ripens cheese.

Rennin solidifies milk proteins.

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CHAPTER 4 5 Chemical Cell Division Composition of the Cell

centrioles

Early prophase • Centrioles migrate. • Chromosomes condense. • Nucleolus disappears. • Nuclear membrane disintegrates.

chromosome spindle fibres

Late prophase • Spindle fibres form. • Spindle fibres attach to chromosomes.

chromosome

Metaphase Chromosomes line up at the equatorial plane (metaphase plate). metaphase plate

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CHAPTER 5 Cell Division centromere

Anaphase • Centromeres divide. • Sister chromatids move toward opposite poles.

Telophase • Spindle fibres disappear. • Chromosomes uncoil. • Nuclear membrane and nucleolus re-appear. cleavage furrow

Cytokinesis Cleavage furrow divides the cell into two identical daughter cells.

daughter cells © Oxford Fajar Sdn. Bhd. (008974-T) 2017

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CHAPTER 5 Cell Division Meiosis I Prophase I • Nuclear membrane disintegrates. • Synapsis (pairing of homologous chromosomes) and crossing over occur. • Spindle fibres form.

Metaphase I • Homologous chromosomes line up on the metaphase plate. • Each homologous chromosome is attached to the fibres from one pole.

Meiosis II Prophase II • Nuclear membrane disintegrates. • Spindle fibres form.

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Metaphase II • Spindle fibres attach to both sides of the centromere. • Chromosomes line up on the metaphase plate.

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CHAPTER 5 Cell Division Anaphase I • Homologous chromosomes are pulled apart. • Centromeres do not divide. • Sister chromatids stay joined.

Anaphase II Centromeres separate and chromatids (daughter chromosomes) are drawn towards opposite poles.

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Telophase I • Chromosomes uncoil (partially). • Nuclear membrane forms. • Cytokinesis occurs.

Telophase II • Nuclear membrane forms. • Cytokinesis occurs. • Four haploid cells are formed from one diploid parent cell.

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CHAPTER 6

The human digestive system Teeth Cut, tear and grind food.

Tongue Helps swallow food.

Salivary glands Secrete salivary amylase to break down starch.

Epiglottis Prevents food from entering trachea.

Oesophagus A tube connecting the mouth to the stomach. Liver • Removes toxins from blood. • Regulates food substances. • Converts excess amino acids to urea. • Produces bile. Gall bladder • Stores bile. • Bile neutralises stomach acid. Large intestine Excess water reabsorbed into blood.

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Nutrition

Stomach Gastric glands secrete pepsin which hydrolyses proteins and rennin which coagulates milk.

Pancreas Secretes pancreatic amylase, trypsin and lipase. Small intestine Digested food substances absorbed into blood. Rectum Stores faeces. Anus Faeces egested. © Oxford Fajar Sdn. Bhd. (008974-T) 2017

CHAPTER 6 Nutrition Adaptation of the small intestine for absorption The villi: • are numerous in number to increase the surface area for absorption • have thin walls for easy absorption of digested food • have a network of blood capillaries for the efficient transport of digested food • have lacteals for the absorption of fatty acids and glycerol fatty acid

glycerol

epithelial cells (absorb glucose, amino acids, fatty acids and glycerol)

lacteal (absorbs fatty acids and glycerol)

blood capillaries (absorb glucose and amino acids) blood capillaries

lymphatic vessel

to liver

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to blood circulatory system

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CHAPTER 6 Nutrition Absorption and assimilation of nutrients End products

Absorbed through

Glucose

Blood capillaries by facilitated diffusion and transported to the liver via the hepatic portal vein.

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• Substrate for cellular respiration. • Excess glucose is converted into glycogen and stored in the liver. • In the cell, glucose is oxidised during cellular respiration. • Used in the synthesis of plasma proteins. • Excess amino acids are deaminated, and urea is excreted. • In the cell, amino acids are needed to synthesise enzymes and hormones.

Amino acids

Fatty acids, glycerol, vitamins A, D, E, K

Assimilation

Lacteals by diffusion and transported in the lymphatic system and finally in the bloodstream.

• Major components of the plasma membrane (phospholipids). • Excess fats are stored in adipose tissue as reserve energy.

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The adaptation of leaf cells for photosynthesis Cross section of a leaf

• Packed tightly together in an upright arrangement to receive maximum sunlight. • Have a high density of chloroplasts to carry out photosynthesis.

Thin and transparent to allow light to penetrate the leaf and reach the chloroplasts cuticle

palisade mesophyll

upper epidermis

spongy mesophyll

lower epidermis

• Have large air spaces between the cells for easy diffusion of water and carbon dioxide to the palisade cells. • Contain chloroplasts which carry out photosynthesis.

stoma

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xylem

bundle sheath collenchyma phloem

• Xylem transports mineral ions and water to the leaf. • Phloem transports products of photosynthesis away from the leaf.

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The mechanism of photosynthesis

1

2

• During the light reaction, chlorophyll captures light energy which excites the electrons. The electrons leave the chlorophyll molecules. • Light energy splits water molecules (photolysis of water) into hydrogen ions and hydroxyl ions.

• Hydrogen ions combine with electrons released by the chlorophyll molecules to form hydrogen atoms. • ATP molecules are also formed.

4

3

• In the dark reaction, hydrogen atoms are used to fix carbon dioxide in a series of reactions catalysed by photosynthetic enzymes. • CH2O is formed. • 6 units of CH2O combine to form one molecule of glucose.

• Each hydroxyl ion loses an electron to form a hydroxyl group. • The electron is received by a chlorophyll molecule. • The hydroxyl groups combine to form water and oxygen.

Word equation for photosynthesis:

6CO2 + 6H2O 24

C6H12O6 + 6O2 © Oxford Fajar Sdn. Bhd. (008974-T) 2017

CHAPTER 7 Respiration Aerobic and anaerobic respiration Aerobic respiration • Complete oxidation of glucose in the presence of oxygen to form carbon dioxide, water and energy. • 38 molecules of ATP are produced. • 2898 kJ of energy is released. • Takes place in the mitochondria. • In all organisms: C6H12O6 6O2 + glucose oxygen 6CO2 + 6H2O water carbon 2898 kJ dioxide energy

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Anaerobic respiration • Incomplete oxidation of glucose in the absence of oxygen to form lactic acid and energy (in muscle cells) or ethanol, carbon dioxide and energy (in yeast). • 2 molecules of ATP are produced. • 210 kJ of energy is released during fermentation by yeast and 150 kJ of energy is released during anaerobic respiration in the muscle cells. • Takes place in the cytoplasm. • In muscle cells: C6H12O6 glucose • In yeast: C6H12O6 glucose

2C3H6O3 lactic acid + 150 kJ energy 2C2H5OH + 2CO2 ethanol carbon + 210 kJ dioxide energy 25

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CHAPTER 6 Nutrition Respiratory structure of fish opercular chamber

gills

Respiratory structure of frogs

filaments

mouth gill arch lamella

heart lungs

lamellae blood flow flow of water

blood vessels

water flows in the opposite direction to the blood flow

Characteristics of the respiratory structures

Respiratory structure of insects spiracle

trachea air sac muscle

spiracles tracheole

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• Numerous folded linings increase surface area to volume ratio for an efficient gaseous exchange. • The linings are thin, one-cell thick to allow a higher rate of gaseous exchange. • The surfaces for the gaseous exchange are constantly moist for easy diffusion of respiratory gases.

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Respiratory structure of humans deoxygenated blood pulmonary arteriole (O2 poor)

oxygenated blood bronchiole pulmonary venule (O2 rich) alveolar space

blood capillaries covering alveoli

alveolus

air O2 O2 CO2

CO2

O2 CO2

• Oxygen diffuses from the alveolus to the blood capillaries. • Carbon dioxide diffuses from the blood capillaries to the alveolus. © Oxford Fajar Sdn. Bhd. (008974-T) 2017

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CHAPTER 7 Respiration Transport of carbon dioxide from body cells to lungs Carbon dioxide released by respiring cells is transported as

• dissolved carbon dioxide (CO2) in the blood plasma (7%) • carbaminohaemoglobin (23%) • bicarbonate ions (70%) Tissue Lung Hb : Haemogl Haemoglobin g obin Blood plasma

CO2

(carbaminohaemoglobin) CO2 Hb +

Hb

H

CO2 H 2O

carbonic anhydrase

H2CO3 HCO3– (carbonic acid) (bicarbonate ion)

H 2O CO2 CO2 Excreted

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Hb

carbonic H CO anhydrase 2 3 CO2 Hb

H+

HCO3–

HCO3–

red blood cell

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CHAPTER 8

Dynamic Ecosystem Energy flow within a food chain 8 When secondary consumers eat primary

consumers, 10% of the primary consumers’ energy is transferred to the secondary consumers.

Quarternary consumer

9 The carnivores also lose energy through respiration, defaecation and excretion.

10 The secondary consumers are then eaten by

Tertiary consumer

tertiary consumers and subsequently the quarternary consumers feed on the tertiary consumers.

11 This is how energy flows from one trophic level to the next.

4 When primary consumers eat the producers,

Secondary consumer

10% of the energy stored in the producer is transferred to the primary consumers.

5 90% of the energy is lost to the environment. 6 Primary consumers use this energy for

growth and movement, and to maintain body temperature.

Primary consumer

7 When consumers excrete and defaecate,

energy is made available to the decomposers.

1 The producer absorbs solar energy and converts it into chemical energy during photosynthesis.

Producer

2 Some of the energy is used by the producer for cellular growth.

3 When the producer dies, this energy is made

available to other organisms by decomposers.

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CHAPTER 8 Dynamic Ecosystem Colonisation and succession in a pond submerged plants

Succession begins with the growth of submerged plants like Hydrilla sp. and Elodea sp.

floating plants

submerged plants

organic matter floating plants

sedges

herbaceous plants

emergent plants (sedges)

cattails

sedges cattails

primary forest

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• When submerged plants die and decompose, their organic matter is converted into humus at the pond base. • The shallower condition becomes more suitable for the growth of floating plants such as Lemna sp. and Eichornia sp. • The addition of more organic matter to the pond base causes the pond to become shallower. • The floating plants are replaced by emergent (amphibious) plants such as sedges and cattails. • When emergent plants die, their decomposed remains add to the sediments at the base of the pond. • The shallow condition of the pond favours the growth of herbaceous plants. • As time passes, the land becomes drier and favours the growth of land plants such as shrubs and bushes. • A primary forest emerges and eventually turns into a tropical rainforest which is known as a climax community.

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CHAPTER 9

Endangered Ecosystem

The process of eutrophication Eutrophication is the artificial nutrient enrichment of an aquatic system with organic matter or inorganic nutrients which cause the excessive growth of aquatic plant life. 1 Excess nutrients cause the rapid growth of algae (algal bloom) in a lake. 2 Algae consume a lot of oxygen and block sunlight penetration. 3 Photosynthesis decreases further the oxygen level in the lake. 4 Algae die without being consumed because they grow faster than their consumers. 5 Photosynthetic organisms die and organic matter accumulates at the bottom of the lake. 6 Dead organic matter is a food source for microorganisms such as aerobic bacteria. 7 Aerobic bacteria use up and deplete the oxygen content in the water. 8 Aquatic organisms compete for oxygen. This results in a high biochemical oxygen demand (BOD). 9 Low concentration of oxygen kills fish.

The effects of global warming • Melting of polar ice caps and glaciers causes sea levels to rise and subsequently floods in low-lying areas. • Droughts occur in more areas and this leads to a drop in crop yields. • Changes the wind direction and distribution of rainfall. Affects agricultural activities. • Spread of disease-carrying vectors such as the vector for dengue fever.

The effects of ozone depletion • Prolonged exposure to ultraviolet (UV) radiation leads to higher risks of skin cancer, cataracts and sunburns. • UV light weakens the immune system. • UV light reduces nutrient contents in soil and this decreases crop yields. • UV light damages chlorophyll and reduces photosynthesis in plants. • UV light kills phytoplankton which affects marine food chains. • Ozone depletion leads to an increase in Earth’s temperature.

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CHAPTER 8 Dynamic Ecosystem A T

S

U

R

N

E

M

O

S

P

2 Some solar radiation is reflected by the atmosphere and Earth's surface.

E

N

H

O

U

S

H

E

R

E

5 Some of the infrared radiation passes through the atmosphere and is lost in space.

E

G

A

S

E

S 6 Some of the infrared radiation is by the greenhouse gas molec absorbed and re-emitted ion passes ules. The direct effect is 1 Solar radiat e. the er warm ph ing of os the m Earth 's surface and the tropospher clear at e. through the Surface gains more heat and infrared radiation is emitted again.

G

3 Solar energy is absorbed by the Earth's surface and warms it...

E A R

T

H

4 ...and is converted into heat causing the emission of the infrared radiation back to the atmosphere

© Oxford Fajar Sdn. Bhd. (008974-T) 2017 First published 2018 ISBN 978 983 47 2299 9 All rights reserved. No part of this publication may be reproduced, stored in a retrieval system, or transmitted in any form or by any means, electronic, mechanical, photocopying, recording or otherwise, without the prior permission of Oxford Fajar Sdn. Bhd. (008974-T)

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