Unit Three:The Organism

Suggested Time Allowance in Class Periods:

3.1 DIVERSITY OF ORGANISMS

3.1.1 Diversity of Organisms

3.1.2 Micro-organisms

3.1.3 Monera, e.g. Bacteria

3.1.4 Fungi

3.1.5 Laboratory Procedures when handling Micro-organisms

3.1.6 Protista, e.g. Amoeba

3.1.7 Plant, e.g. the Flowering Plant

3.1.8 Animal, e.g. the Human

H.3.1.9 Nature of Bacteria and Fungi

H.3.1.10 Growth Curves

Five-kingdom system of classification: Monera (Prokaryotae), Protista (Protoctista), Fungi, plant, and animal. (Further sub-classification not required).

Distribution of bacteria and fungi in nature.

Bacterial cells: basic structure (including plasmid DNA), three main types. Reproduction. Nutrition.

Factors affecting growth.

Understanding of the term "pathogenic".

Definition and role of "antibiotics".

Saprophytic and parasitic forms.

Rhizopus: structure and life cycle.

Nutrition.

Yeast: structure and reproduction (budding).

Precautions when working with microorganisms. Asepsis and sterility: definition of each term as applied to living organisms.

Containment and disposal.

Amoeba ­ cell organisation to include nucleus and sub-cellular structures.

Plant kingdom as exemplified by the flowering plant. (Refer to the remaining Sub-units of Unit 3).

Animal kingdom as exemplified by the human. (Refer to the remaining Sub-units of Unit 3.)

Prokaryotic nature of bacteria.

Eukaryotic nature of fungi.

Growth curves of micro-organisms

Economic importance of bacteria: examples of any two beneficial and any two harmful bacteria.

Potential abuse of antibiotics in medicine.

Mention of edible and poisonous fungi.

Economic importance of fungi: examples of any two beneficial and any two harmful fungi.

Batch and continuous flow food processing.

3.2 ORGANISATION AND THE VASCULAR STRUCTURES

3.2.1 Organisational Complexity of the Flowering Plant

3.2.2 Organisational Complexity of the Human

H.3.2.3 Blood Cells (Extended Study)

H.3.2.4 Heartbeat Control

Organisational complexity of the flowering plant as exemplified by the root, stem, leaf, flower, seed, and transport/vascular structures.

Function of the root and shoot system. Explanation of the term "meristem" ­ location in the root and shoot. Location of three tissue types ­ dermal, ground and vascular in transverse and in longitudinal sections of the root and stem. Xylem and phloem as examples of vascular tissues ­ their function and structure.

Identification of dicotyledons and monocotyledons under the headings: woody/herbaceous, arrangement of floral parts, arrangement of vascular bundles, cotyledon or seed leaf number.

Organisational complexity of the human.

The circulatory system: description of the structures and organisation of tissues in the closed circulatory system in humans, strong muscular heart and vessels (arteries, veins, capillaries, venules, arterioles).

Role of muscle tissues and valves. Two-circuit circulatory system.

Drawing of the structure of the heart, the main pathways of blood circulation, including the hepatic portal system.

Cardiac supply through the cardiac artery and vein.

Simple understanding of:

• heartbeat and its control
• pulse
• blood pressure.

The lymphatic system:

• structure: lymph nodes, lymph vessels
• any three functions.

Composition of blood, role of red blood cells, white blood cells, platelets, and plasma. (Classification of white blood cells not required).

Blood grouping ­ names of the common blood groups A, B, AB, O and the Rhesus factors.

More detailed treatment of red blood cells ­ e.g. absence of nucleus, absence of mitochondria. White blood cells ­ classification as lymphocytes and monocytes.

An awareness of specialised heart muscle tissue and the existence and location of pacemaker nodes (SA and AV).

The heart cycle, systole and diastole periods.

Prepare and examine microscopically the transverse section of a dicotyledonous stem (x100, x400).

Dissect, display and identify an ox's or a sheep's heart.

Investigate the effect of exercise on the breathing rate or pulse of a human.

3.3 TRANSPORT AND NUTRITION

3.3.1 Nutrition in the Flowering Plant

3.3.2 Modified Plant Food Storage Organs

3.3.3 Nutrition in the Human

3.3.4 Human Digestive System

3.3.5 Blood Transport of Nutrients

3.3.6 Balanced Human Diet

H.3.3.7 Cohesion ­ Tension Model of Xylem Transport

Autotrophic nature of plants.

Description of the uptake and process of transport of the following through the plant:

• water: to include reference to root hairs, root cortex, xylem, osmosis, diffusion, root pressure, transpiration, and stomata
• minerals: to include solubility in water, transport from the roots to all parts of the plant by the same route as water
• carbon dioxide: directly from respiring cells or through stomata
• photosynthetic products: production of carbohydrate and transport through phloem sieve tube cells.

One example of a root, stem and leaf modification as a food storage organ.

Heterotrophic organisms ­ "omnivore" (human), "herbivore" and "carnivore" ­ definition of terms.

Explanation of the term "digestion". Outline the need for digestion and a digestive system.

Explanation of the terms "ingestion", "digestion", "absorption" and "egestion" as related to the sequence in the human digestive tract.

Macrostructure and basic function of the alimentary canal and associated glands in the digestion and transport of nutrients.

Explanation of the mechanical breakdown and transport of food, to include the role of teeth, peristalsis, and the stomach.

Explanation of the chemical breakdown of food, to include:

• bile salts
• the role, production site, pH at a named location of action and products of an amylase, a protease and a lipase enzyme.

Two functions of symbiotic bacteria in the digestive tract.

Benefits of fibre.

Basic structure of the small intestine and large intestine in relation to their functions.

Description of the composition of blood fluid as a transport system of nutrients, the absorption of nutrients from the villi, transport through the hepatic portal vein to the liver. The function of the liver (without biochemical pathways). The transport of nutrients to all nutrientrequiring cells of the body, and the transport of waste products to the kidney.

Explain the concept of a balanced diet, variety, and moderation. Relate its importance to age, sex and activity (detailed breakdown not required), and to variety from a selection of food groups ­ milk and milk products; meat, fish and poultry; breads and cereals; fruit and vegetables; others, e.g. fats, oils, alcohol.

As related to attractive forces of water molecules, cohesive property, role of transpiration. Refer to the work of Dixon and Joly.

3.4 BREATHING SYSTEM AND EXCRETION

3.4.1 Homeostasis

3.4.2 Necessity for Homeostasis

3.4.3 The Structure of an Exchange System in Flowering Plants

3.4.4 The Breathing System in the Human

3.4.5 Plant Excretion

3.4.6 The Excretory System in the Human

H.3.4.7 Carbon Dioxide: A Controlling Factor in Gaseous Exchange

H.3.4.8 The Nephron as a Unit of Kidney Function

Definition of "homeostasis".

The necessity for homeostasis in living organisms.

Examination of the structure of the leaf in relation to gaseous exchange. Reference to the presence of lenticels in stem structures.

Macrostructure and basic function of the breathing tract in humans.

Essential features of the alveoli and capillaries as surfaces over which gas exchange takes place.

Description of the mechanism of the breathing system in the exchange of gases in humans.

The role of leaves as excretory organs of plants.

Role of the excretory system in homeostasis. Function, location and excretory products of the lungs, skin, and urinary system.

Macrostructure and basis function of the urinary excretory system in humans (kidney, ureters, urinary bladder, and urethra).

Role of the kidney in regulating body fluids. Identification of the site of filtration. Reabsorption in the cortex, in the medulla and renal pelvis.

Description of the pathway of urine from the kidney to the urethra.

Carbon dioxide level as a controlling factor in stomatal opening and in the human breathing (respiratory) system.

The nephron structure and its associated blood supply. Formation of urine: Bowman's capsule, passage of glomerular filtrate through the proximal convoluted tubule, where reabsorption of required body substances takes place ­ glucose, amino acids, some salts and water reabsorbed into the blood by osmosis, diffusion, and active transport. More water reabsorbed in the Loop of Henle and the distal convoluted tube. Urine passes into the pelvis of the kidney and to the bladder for storage. Reabsorption of water in the collecting duct is under hormonal influence (ADH). Its action depends on the water content of the blood. (No further details required).

3.5 RESPONSES TO STIMULI

3.5.1 Structures for Response

3.5.2 Responses in the Flowering Plant

3.5.3 Responses in the Human

3.5.4 Viruses

H.3.5.5 Auxins

H.3.5.6 Plant Growth Regulators and Animal Hormones (Extended Study)

H.3.5.7 Human Immune System (Extended Study)

H.3.5.8 Growth and Development in Bones

Chemical or hormonal system, nerve and sense organ system, muscular, skeletal and an immune system.

Growth regulation.

Tropisms: definition of the following: "phototropism", "geotropism", "thigmatropism", "hydrotropism", and "chemotropism".

Examples of phototropism and geotropism.

Regulatory system: definition of a "growth regulator", transport through the vascular system, combined effect, growth promoter and growth inhibitor.

Name four methods of anatomical or chemical adaptation that protect plants.

The nervous system: two-part division into the central nervous system (CNS) and the peripheral nervous system (PNS). Neuron: its structure and function, with reference only to cell body, dendrites, axon, myelin sheath, Schwann cell, and neurotransmitter vesicles. Movement of nerve impulse. (Detailed knowledge of electro-chemistry not required). Synapse.

Activation and inactivation of neurotransmitter. Role and position of three types of neuron: sensory, motor and interneuron.

The senses, with the brain as an interpreting centre. Knowledge of the senses. Study of the eye and the ear. Corrective measures for long and short sight or for hearing.

Note: The following are not required: biochemical action, detailed structure of cochlea and semicircular canals in ear, names of sensory receptors in the skin.

Central nervous system: brain and spinal cord. Location and function of the following parts of the brain: cerebrum, hypothalamus, pituitary gland, cerebellum, and medulla oblongata. Cross-section of spinal cord indicating: white matter, grey matter and central canal (refer to their constituent bodies), three-layer protective tissue ­ the meninges. Dorsal and ventral roots of the spinal nerve.

Peripheral nervous system: location of nerve fibres and cell bodies. Role, structure and mechanisms of the reflex action. (Cranial nerves, sympathetic and parasympathetic systems are not required).

Endocrine system: definition of a "hormone". Comparison with nerve action, distinction between exocrine and endocrine glands, with examples. Location of the principal endocrine glands in the human. For each of the glands name one hormone and give its functions. For one hormone give a description of its deficiency symptoms, excess symptoms, and corrective measures.

Musculoskeletal system: description of the structure and functions of the skeleton. Component parts of the axial skeleton: skull, vertebrae, ribs, and sternum. Position and function of discs in relation to vertebrae.

Component parts of the appendicular skeleton: pectoral and pelvic girdles and their attached limbs.

Macroscopic anatomy of a long bone: medullary cavity, compact bone, spongy bone, and cartilage.

Function of the following: cartilage, compact bone, spongy bone (include red and yellow marrows). (T.S of bone is not required).

Classification, location and function of joints: immovable, slightly movable, free-moving or synovial.

Role of cartilage and ligaments in joints.

Role of tendons.

General relation of muscles to the skeleton ­ antagonistic muscle pairs as exemplified by one human pair.

The defence system in humans: general defence system to include the skin and mucous membrane lining of the breathing, reproductive and digestive tracts. Phagocytic white blood cells.

Specific defence system (immune system): antigen antibody response. Definition of "induced immunity".

Viruses: identify the problem of definition. Variety of shapes. Basic structure. Viral reproduction.

Study auxin as an example of a plant growth regulator under the headings of production site(s), function, and effects.

Explanation of the mechanism of plant response to any one external stimulus.

Description of the feedback mechanism of any one animal hormonal system.

Role of lymphocytes: B and T cell types. Role of B cells in antibody production. Role of T cells as helpers, killers, suppressors, and memory T cells.

Osteoblast role in bone growth. Terminating development of adult height. Role of osteoblasts in bone cell replacement. Bone renewal. Role of calcium in bone.

Use of plant regulators: any two examples

Nervous system disorders: any one example of a nervous system disorder, from the following: paralysis and Parkinson's disease; one possible cause, prevention, and treatment.

Hormone supplements: two examples of their use.

Disorders of the musculoskeletal system: one example of a musculoskeletal disorder, from the following: arthritis and osteoporosis; one possible cause, prevention, and treatment.

Vaccination and immunisation.

Economic and medical importance of viruses: two harmful examples, one beneficial example.

.

3.6 REPRODUCTION AND GROWTH

3.6.1 Reproduction of the Flowering Plant

3.6.2 Sexual Reproduction in the Human

H.3.6.3 Sexual Reproduction in the Flowering Plant (Extended Study)

H.3.6.4 Human Embryo Development (Extended Study)

H.3.6.5 Sexual Reproduction in the Human (Extended Study)

Sexual:

Structure and function of the floral parts: sepal, petal, stamen, and carpel.

(Terms "calyx", "corolla", "androecium" and "gynoecium" not required).

Pollen grain produces male gametes (statement only).

Embryo sac produces an egg cell and polar nuclei (statement only).

Definition and methods of "pollination": self-pollination and cross-pollination, to include wind and animal.

Definition of "fertilisation":

• fertilisation of an egg to form a diploid zygote, which develops into an embryo
• second fertilisation with polar nuclei results in the formation of the endosperm.

Seed structure and function of the following parts: Testa, plumule, radicle, embryo and cotyledon attachments. Embryo and a food supply as contained either in an endosperm or in seed leaves (the cotyledons). Monocotyledon, dicotyledon classification and distinguishing features. Reference to nonendospermic seed.

Fruit formation ­ simple statement. (Classification of fruits not required).

Fruit and seed dispersal: examples of wind, water, animal and self-dispersal. Emphasise the need for dispersal.

Definition and advantages of "dormancy".

"Germination": definition, factors necessary, role of digestion and respiration. Stages of seedling growth.

Vegetative propagation: asexual reproduction in plants. One example each from stem, root, leaf, and bud. Comparison of reproduction by seed and by vegetative propagation.

General structure of the reproductive system ­ male and female. Functions of the main parts.

Role of meiosis in the production of sperm cells and egg (ova). (The detailed treatment of spermatogenesis and oogenesis are not required).

Definition of "secondary sexual characteristics".

Role of oestrogen, progesterone, and testosterone.

The menstrual cycle: the events and outlined role of oestrogen and progesterone.

Copulation.

Location of fertilisation.

Implantation, placenta formation and function. (Detailed embryological terms not required).

Birth ­ outline of process.

Pollen grain development from microspore mother cells: meiotic division, mitotic division, generative and tube nuclei production, formation of pollen grain.

Embryo sac development: megaspore mother cell, meiotic division, cell disintegration, mitotic division in the production of eight cells of the embryo sac, one of which is the egg cell.

(Antipodal cells and synergids not required).

Sequence of development from fertilised egg, morula, blastocyst, existence of amnion, placenta formation from embryonic and uterine tissue. Development of embryo up to third month.

Detailed study of the menstrual cycle and hormonal control.

Seedless fruit production caused by genetic variety of plants and growth regulators.

Mention of dormancy in agricultural and horticultural practices.

Artificial propagation in flowering plants, any four methods used to artificially propagate plants.

Sub-unit and Topic Depth of Treatment Contemporary Issues Practical Activities and Technology

Birth control ­ natural, mechanical, chemical and surgical methods of contraception.

Infertility:

One cause of male infertility from the following disorders: low sperm count, low sperm mobility, endocrine gland failure. Availability of corrective measures.

One cause of female infertility from the following disorders: blockage of the Fallopian tube, endocrine gland failure. Availability of corrective measures.

In-vitro fertilisation and implantation.

Biological benefits of breastfeeding.

Menstrual disorders: one example of a menstrual disorder from the following: endometriosis and fibroids; one possible cause, prevention and treatment

Investigate the effect of water, oxygen and temperature on germination.

Use starch agar or skimmed milk plates to show digestive activity during germination.