Biology

I Cells and Molecules of Life

Overview

Cells and biomolecules are fundamental units of life. Organisms are built up of these fundamental units which function as an integrated whole. The study of the structure and function of cells will lay the foundation for students to understand and relate cellular processes to the essential life processes of organisms. The study of the discovery of cells will enable students to appreciate the contribution of technology to the advancement of science and the dynamic nature of biological knowledge.

Scientific Inquiry

This should enable students to:

 ask relevant questions, identify problems and formulate hypotheses for investigations related to cells and molecules of life;

 plan and conduct scientific investigations in the area of cellular structures and functions;

 use appropriate instruments and proper techniques for carrying out practical work (e.g.

food tests, preparation of temporary mounts and microscopic examination);

 make careful observations and accurate records (e.g. examine prepared slides or temporary mounts of tissues and make biological drawings); and

 identify and explain the importance of control variables in scientific investigations (e.g.

the study of enzymatic activities and osmosis).

STSE Connections

This should enable students to:

 be aware of the applications of biological knowledge of cells and molecules of life in society;

 appreciate the role of science and technology in understanding the molecular basis of life; and

 recognise that the development of microscopic technology, computing technology and image analysing technology may lead to the advancement of biological knowledge.

Nature and History of Biology This should enable students to:

 be aware of the dynamic nature of biological knowledge (e.g. the understanding of cell membrane, sub-cellular organelles and cellular processes);

 recognise the contributions of various people (e.g. Robert Hooke and Theodor Schwann) to developments in biology; and

 be aware that biological knowledge and theories are developed through observations, hypotheses, experimentations and analyses (e.g. fluid mosaic model of cell membrane structure).

Students should learn Students should be able to a. Molecules of life

Water and inorganic ions (e.g. nitrogen, magnesium, calcium and iron)

Biomolecules: carbohydrates, lipids, proteins and nucleic acids

 Building blocks

 Functions

 Relate the significance of water, inorganic ions and biomolecules to life.

b. Cellular organisation Discovery of cells

Cell membrane

 Properties and functions

Sub-cellular structures and their functions

 Nucleus and chromosomes, endoplasmic reticulum, mitochondrion, chloroplast, cell wall and vacuole

Prokaryotic cells (e.g. bacterial cells) and eukaryotic cells

 Appreciate the contribution of technological development of the microscope to the discovery of cells.

 Prepare temporary mounts of specimens for examination, and make observations and drawings under a light microscope.

 Use the fluid mosaic model to explain the properties and functions of cell membrane.

 Appreciate the uses and limitations of scientific models.

 Compare the cellular organisation of animal and plant cells.

 Identify cell organelles as seen under light and electron microscopes.

Students should learn Students should be able to

 Compare the sub-cellular organisation of prokaryotic and eukaryotic cells.

c. Movement of substances across membrane Diffusion, osmosis and active transport

Occurrences of phagocytosis in cells

 Account for the movement of substances across membrane using the concepts of diffusion, osmosis and active transport.

 Apply the concept of osmosis to explain plasmolysis and haemolysis.

d. Cell cycle and division Stages of cell cycle

 Cell growth, nuclear division and cytoplasmic division

Nuclear division

 Mitosis

 Meiosis

 Understand the importance of cell division in growth and reproduction.

 Recognise the various stages of cell cycle.

 Outline and compare the processes of mitosis and meiosis.

e. Cellular energetics

Metabolism: catabolism and anabolism

 Occurrence of catabolic and anabolic processes in cells

Enzymes and enzymatic reactions

 Properties and roles of enzyme

 Active site and specificity

 Factors (temperature, pH and inhibitors) affecting the rate of enzymatic reactions

 Application of enzyme in everyday life

 Distinguish between catabolic and anabolic processes.

 Recognise the properties of enzyme and its roles in metabolism.

 Explain enzyme specificity in terms of active site.

 Explain the effects of factors on the rate of enzymatic reactions.

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Suggested Learning and Teaching Activities a. Molecules of life

 Discuss whether life can exist without water, and the possible benefits of drinking mineral water or isotonic drinks.

 Perform common biochemical tests (e.g. Benedict’s test, iodine test, grease spot test, and different types of test papers) to identify the presence of biomolecules in living tissues.

b. Cellular organisation

 Read articles about the discovery of cells.

 Conduct a project to explore the contribution of the development of the microscope to the understanding of cells.

 Discuss the variations of the number of mitochondria in different tissues and cell types.

 Prepare temporary mounts of animal and plant tissues for examination under a light microscope.

 Examine electron micrographs or live cell images of prokaryotic, eukaryotic cells and sub-cellular structures.

 Construct a model to represent the structure of cell membrane (e.g. using tank and ping-pong balls).

c. Movement of substances across membrane

 Perform practical work to study osmosis at cellular, tissue or organ levels.

 Examine live cell images of the processes involved in the movement of substances across membrane.

d. Cell cycle and division

 Observe and identify the different stages of mitosis and meiosis, using prepared slides, photomicrographs or live cell images.

e. Cellular energetics

 Perform practical work to demonstrate the breaking down or building up action of enzymes.

 Design and perform investigations to study the effects of temperature, pH or inhibitors on the activities of enzymes; and to find out some commercial applications of enzymes (e.g. bioactive washing powder and meat tenderiser).

II Genetics and Evolution

Overview

Through the study of basic genetics, students will acquire knowledge and develop an understanding of concepts of genes and their roles in the life of organisms. The study of molecular genetics will lay the foundation for students to study further in the field of biotechnology and be aware of its impact on society.

The study of biodiversity will help students to recognise its complexity and the adaptations of different groups of organisms to their environment. Moreover, a phylogenetic approach to the classification system is adopted, which helps them to understand the development of the classification system with evidence gathered from molecular genetics. This will enable students to appreciate the phenomena of evolution and develop their curiosity about the origins of life. In addition to Darwin’s theory, students are encouraged to explore other scientific explanations for the origins of life and evolution, to help illustrate the dynamic nature of scientific knowledge.

Scientific Inquiry

This should enable students to:

 make careful observations and accurate records (e.g. observe distinguishing features for identifying organisms, and variations in humans);

 use appropriate instruments and proper techniques for carrying out practical work on molecular genetics (e.g. DNA extraction and gel-electrophoresis);

 classify, collate and display both first and second hand data (e.g. construct a pedigree of the inheritance of some human traits);

 use diagrams and physical models as visual representations of phenomena and relationships arising from the data (e.g. genetic diagrams and DNA model); and

 formulate and revise scientific explanations and models using logic and evidence (e.g.

use of fossil records as evidence for evolution).

STSE Connections

This should enable students to:

 be aware of the application of knowledge of basic and molecular genetics in society and its social, ethical and economic implications;

 be aware that societal needs have led to technological advances (e.g. recombinant DNA technology and DNA fingerprinting);

 appreciate the contribution of the Human Genome Project (HGP) and the application of biotechnology to humans and society;

 appreciate the role of science and technology in understanding the complexity of life forms and their genetics;

 understand how science has been influenced by societies (e.g. various views on the origins of life and evolution ); and

 explain how the knowledge of biotechnology may lead to the development of new technologies and how new technologies may lead to further understanding of inheritance.

Nature and History of Biology This should enable students to:

 be aware of the dynamic nature of biological knowledge (e.g. from basic genetics to molecular genetics, and the development of classification systems);

 recognise the contributions of various people (e.g. Gregor Mendel, James Watson, Francis Crick, Charles Darwin, Sir Alfred Russel Wallace and Jean Baptiste Lamarck) to the understanding of genetics and evolution;

 appreciate the advancement of the study of genetics from traditional breeding experiments to molecular experimentation and analysis; and

 be aware that biological knowledge and theories are developed through observations, hypotheses, experimentations and analyses (e.g. Mendel’s work).

Students should learn Students should be able to a. Basic genetics

Mendel’s laws of inheritance

Inheritance in humans

 Multiple alleles: ABO blood groups

 Sex linkage

 Sex determination

Pedigree analysis

 Understand the law of segregation and law of independent assortment.

 Apply Mendel’s laws of inheritance to solve genetic problems.

 Understand the inheritance of ABO blood groups and sex-linked traits.

 Recognise the role of sex chromosomes in sex determination of humans.

 Analyse pedigree to study the inheritance of

Students should learn Students should be able to Variations in characteristics

 Continuous variation

 Discontinuous variation

 Causes of variation

 hereditary information

 environmental factors

 mutation

 Explain the causes of different types of variations in characteristics.

b. Molecular genetics

Chromosomes, genes and nucleic acids

Biotechnology

 Recombinant DNA technology

 DNA fingerprinting

 Human Genome Project (HGP) and its implications

 Describe the structural and functional relationships of chromosomes, genes and nucleic acids.

 Recognise the applications of recombinant DNA technology and DNA fingerprinting.

 Recognise the contributions and limitations of the data obtained from the HGP.

 Appreciate the joint effort of scientists in international genomics projects.

c. Biodiversity and evolution Diversity of life forms

Classification of organisms

 Need for classification

 Classification approaches proposed by Carl Woese

 Six kingdoms (Eubacteria,

Archaebacteria, Protista, Fungi, Plantae and Animalia)

 Three domains (Bacteria, Archaea and Eukarya)

Origins of life

Evolution

 Origin of species

 Appreciate the existence of various life forms in the world, and the different ways through which organisms adapt to their habitats.

 Be aware that modern classification is based on the phylogenetic relationships of organisms.

 Appreciate that classification systems are subject to change when new evidence appears.

 Recognise the use of classification systems and binomial nomenclature.

 Construct and use dichotomous keys to identify unknown organisms.

 Classify organisms into six kingdoms.

 Appreciate that there are various explanations for the origins of life.

 Be aware of the limitations of using fossil record as evidence of evolution, and the

Suggested Learning and Teaching Activities a. Basic genetics

 Read articles about how Gregor Mendel contributed to the study of genetics.

 Use computer simulations and other materials (e.g. genetic corn) to study patterns of inheritance.

 Observe and analyse variations in humans (e.g. height and tongue rolling).

 Construct and/or a pedigree of the inheritance of some human traits (e.g. haemophilia, tongue rolling and ear lobes).

b. Molecular genetics

 Construct models of DNA and RNA.

 Read about the work of some biologists (e.g. James Watson and Francis Crick) in the discovery of DNA.

 Use audiovisual materials to illustrate the processes of recombinant DNA technology and DNA fingerprinting.

 Perform practical work to extract DNA from living tissues (e.g. onion tissues); and to separate DNA fragments by gel-electrophoresis.

 Search for information on the use of DNA fingerprinting in forensic science.

 Make a chart or create a timeline of the discoveries that have arisen from the HGP.

c. Biodiversity and evolution

 Visit a herbarium, country park or special area (e.g. Lions Nature Education Centre, and Tai Po Kau Nature Reserve).

 Use specimens, audiovisual materials, games, etc. to study the diversity of organisms, and their ways of life.

 Classify organisms into major categories according to a classification system.

 Discuss the advantages and limitations of different classification systems, and why the classification of some organisms has been changed over time.

 Search for information on other classification systems; and binomial naming of some organisms.

 Construct and use dichotomous keys to identify organisms from a local habitat.

 Read about the work of Carl Linnaeus and his system of naming organisms; the different explanations for the origins of life; and the work of some biologists (e.g. Jean Baptiste Lamarck, Charles Darwin and Sir Alfred Russel Wallace) on evolution.

III Organisms and Environment

Overview

Organisms are an integral part of the environment. Their ways of life and living are closely related to the environment where they live in. Based on this perspective, students will gain knowledge and understanding of organisms and their environment.

Firstly, students will study how organisms obtain their basic needs for oxygen, water and food from the environment. Life processes, such as nutrition, gas exchange, and transport involved, will be studied in an integrated manner so as to enhance understanding of the structures and function of an organism as a whole. Secondly, students will study reproduction, growth and development to understand how organisms perpetuate and proliferate in the environment. The human is used as a model for students to understand the essential life processes of animals. Thirdly, students will examine how organisms detect changes in the environment and make appropriate responses for their survival, and how humans maintain a steady internal environment. Students will then explore how organisms interact with each other and with their environment as a whole. Finally, the dynamic nature of the ecosystems that involves energy flow and materials cycling will also be investigated. Students are expected to develop an awareness of the impact of human activities on the ecosystems and recognise the need for conservation.

Scientific Inquiry

This should enable students to:

 make careful observations and accurate records (e.g. examine prepared slides or temporary mounts of roots, stems and leaves, and make biological drawings);

 ask relevant questions, identify problems and formulate hypotheses for investigations related to life processes and ecosystems;

 plan, conduct and write reports on scientific investigations in areas of life processes and ecosystems;

 select and design appropriate methods of investigations for specific purposes (e.g. use transects and quadrats to collect samples in field studies);

 identify and explain the importance of control variables in scientific investigations (e.g.

the study of the effects of different minerals on plant growth, and the action of digestive enzymes);

 explain why sample size, random sampling, replicates and repeat procedures are important in scientific investigations (e.g. field studies);

 use appropriate instruments and proper techniques for carrying out practical work (e.g.

food tests, preparation of temporary mounts, microscopic examinations, dissections and field study techniques); and

 use diagrams, graphs, flow charts and physical models as visual representations of phenomena and relationships arising from the data (e.g. use food chains, food webs, and pyramid of numbers to represent relationships between organisms in ecosystems and distribution of organisms).

STSE Connections

This should enable students to:

 evaluate the impact of the application of biology to human activities (e.g. dietary requirement, birth control and pollution control);

 analyse ways in which scientific and technological advancement (e.g. computing technology and image analysing technology) have enhanced our understanding of complex life processes;

 develop sensitivity and responsibility in striking a balance between the needs of humans and a sustainable environment; and

 be aware of the application of biological knowledge (e.g. balanced diet, birth control and sewage treatment) in society and its social, ethical, economic and environmental implications.

Nature and History of Biology This should enable students to:

 understand that science is a human endeavour through the study of essential life processes of organisms and interactions within our environment;

 be aware that biological knowledge and theories are developed through observations, hypotheses, experimentations, and analyses (e.g. the study of tropism, transpiration pull and field ecology);

 recognise the complexity of the physiological processes of organisms and the environment; and

 understand the nature and limitations of scientific activity (e.g. investigations on various physiological processes and ecosystems).

Students should learn Students should be able to a. Essential life processes in plants

Nutrition in plants

 Plants as autotrophs

 Photosynthesis

 Need for minerals

 Absorption of water and minerals

Gas exchange in plants

 Occurrence of gas exchange in different parts of plant

 Gas exchange in leaves

Transpiration

 Process and significance

 Factors (humidity, light intensity and wind) affecting the rate of transpiration

Transport of substances in plants

 Transport of water and minerals

 Translocation of organic nutrients

Support in plants

 Cell turgidity

 Physical nature of xylem

 Appreciate the significance of plants as autotrophs.

 Explain the need for minerals in plants.

 Relate the structure of roots to their functions in water absorption.

 Relate the features of leaves to gas exchange and prevention of water loss.

 Explain the effects of light intensity on gas exchange in plants.

 Make connections between transpiration, absorption and transport of water, and cooling of plant.

 Explain the effects of environmental factors on the rate of transpiration.

 Describe the path of materials transport in flowering plants.

 Compare the means of support in herbaceous and woody dicotyledonous plants.

b. Essential life processes in animals Nutrition in humans

 Humans as heterotrophs

 Food requirements and functions of different food substances

 Carbohydrates

 Lipids

 Proteins

 Vitamins

 Minerals (e.g. calcium and iron)

 Dietary fibre

 Explain the effect of age, activity and pregnancy on dietary requirements.

 Relate health problems to improper diet.

 Explain the significance of mechanical and chemical digestion.

 Understand the digestion and absorption processes in various parts of the alimentary canal.

 Illustrate the adaptive features of the small intestine for food absorption.

Students should learn Students should be able to

 Balanced diet

 Ingestion

 Dentition

 Mastication

 Digestion

 General plan of the digestive system

 Digestion of carbohydrates, proteins and lipids in various parts of the alimentary canal

 Absorption and assimilation

 Structural adaptation of small intestine for food absorption

 Role of liver

 Fate of absorbed food

 Egestion

 Describe the routes of the transport of absorbed food and their fates in cells and tissues.

Gas Exchange in humans

 General plan of the breathing system

 Gas exchange in air sacs

 Routes of transport of respiratory gases

 Mechanism of ventilation

Transport of substances in humans

 General plan of the circulatory system and lymphatic system

 Composition and functions of blood, tissue fluid and lymph

 Exchange of materials between blood and body cells

 Formation of tissue fluid

 Understand the exchange of respiratory gases between the body cells and the external environment.

 Relate the structure of various parts of the breathing system to gas exchange.

 Relate the structure of various components of the circulatory system and lymphatic system to transport.

 Describe the exchange of materials and the formation of tissue fluid.

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c. Reproduction, growth and development Reproduction in humans

 General plan of the male and female reproductive systems

 Structure of sperm and ovum

 Relate the structure of various parts of the reproductive systems to their functions.

 Recognise the roles of sperm and ovum in sexual reproduction.

Students should learn Students should be able to

 Menstrual cycle

 Cyclic changes in uterine lining

 Ovulation

 Fertilisation

 Development of embryo and foetus

 Placenta

 Identical twins and fraternal twins

 Birth process

 Parental care

 Birth control

 Describe the transfer of semen during sexual intercourse and the process of fertilisation.

 Relate the structure of the placenta to its role in the development of foetus.

 Recognise the significance of parental care and the advantages of breast-feeding.

 Understand the biological basis of various methods of birth control.

d. Coordination and response Stimuli, receptors and responses

 Light as stimulus: the human eye

 Major parts of the eye

 Rod cells and cone cells

 Colour vision

 Eye accommodation

 Eye defects (long sight, short sight and colour blindness)

 Light as stimulus: phototropic response in plants

 Responses of root and shoot

 Role of auxins

 Sound as stimulus: the human ear

 Major parts of the ear

 Understand the roles of sense organs and receptors in detecting changes in the environment.

 Relate the structure of major parts of the eye to vision.

 Explain the causes of eye defects.

 Describe how long sight and short sight are corrected with glasses.

 Be aware of the surgical methods for eyesight correction.

 Recognise the significance of phototropism.

 Understand the mechanism of phototropic responses in root and shoot.

 Relate the structure of major parts of the ear to hearing.

Nervous coordination in humans

 General plan of the nervous system

 Central nervous system

 Functions of main parts of the brain:

cerebrum, cerebellum and medulla oblongata

 Recognise the role of the central nervous system.

 Distinguish different types of neurones in terms of structure and function.

 Describe the transmission of nerve impulses across a synapse.

Students should learn Students should be able to

 Functions of spinal cord

 Neurone: sensory neurone, interneurone and motor neurone

 Synapse

 Reflex arc and reflex action

 Voluntary actions

 Compare the nature of reflexes and voluntary actions with examples.

Hormonal coordination in humans

 Nature of hormonal coordination

 General plan of the endocrine system

 Understand the nature of hormonal coordination.

 Use an example to illustrate hormone mediated response.

 Compare hormonal and nervous coordination.

e. Homeostasis

Concept of homeostasis

 Importance of homeostasis

 Feedback mechanism

Parameters of the internal environment

 Glucose level and gas content in blood, water content and body temperature

Regulation of blood glucose level

 Roles of liver, pancreas, insulin and glucagon

 Explain the principle of feedback mechanism with reference to the regulation of blood glucose level.

 Appreciate that the internal environment of human body is maintained by the nervous system and the endocrine system.

f. Ecosystems

Levels of organisation

 Species, population, community, ecosystem, biome and biosphere

Major ecosystem types

 Freshwater stream, rocky shore, mangrove, grassland and woodland

 Be aware that organisms and their environment are studied at different levels of organisation.

 Appreciate the existence of a variety of ecosystems in the local environment.

在文檔中 Combined Science Curriculum and Assessment Guide (Secondary 4 - 6) (頁 86-105)