SPM Biology 4 Chemical Composition of the Cell (Part 4)

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SPM Biology 4 Chemical Composition of the Cell (Part 3)

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SPM Biology 4 Chemical Composition of the Cell (Part 2)

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SPM Biology 4 Chemical Composition of the Cell (Part 1)

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STPM Biology Biological Molecules (Part 20)

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STPM Biology Biological Molecules (Part 19)

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STPM Biology Biological Molecules (Part 18)

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STPM Biology Biological Molecules (Part 17)

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SPM Biology 10 Transport (Part 7)

SPM Biology 10 Transport: The Blood Vessels

There are 3 types of blood vessels:

1. Artery: carries blood away from the heart to all organs in the body.
2. Vein: carries blood from the organs back to the heart.
3. Capillaries: The smallest blood vessels which connect the artery and the vein.

   

   Artery, Vein, and Capillaries

Comparison of  artery, vein and capillary

SPM Biology 10 Transport (Part 6)

SPM Biology 10 Transport: Circulatory System

There are 2 types of circulatory system in human and other animals:

1. Closed circulatory system
2. Open circulatory system

1. Closed circulatory system

• The blood is contained in blood vessels and flows continuously in blood vessels.
• Valves can be found to maintain the flow of blood in one direction only.
• This system is found in larger animals such as vertebrates.

2. Open circulatory system

• The blood is not contained in blood vessels and is pumped from the heart into the cavity or space around the body cells.
• This system is only found in smaller animals such as insects and shellfish.

  

  Differences between open and closed circulatory system

Circulatory system in human

1. The circulatory system in human is called double closed and complete circulatory system.

2. This is because the blood flows in blood vessels and it passes through the heart twice in one complete circulation. 

Human circulation system

3. There are 2 main circulations:

1. Pulmonary circulation (heart → lungs → heart)
2. Systemic circulation (heart → all body tissues → heart)

Pulmonary circulation

• Deoxygenated blood is pumped out from the right ventricle into the pulmonary artery which transports the blood to left and right lungs.
• At the lungs, gaseous exchange occurs. The deoxygenated blood in the pulmonary artery receives oxygen and becomes oxygenated blood and is transported from the lungs to the left atrium of the heart by pulmonary vein.

  

  Pulmonary circulation

• The main function of pulmonary circulation: to change deoxygenated blood to oxygenated blood.

Systemic circulation

• Oxygenated blood from the lungs which enters the left atrium of the heart is pumped into the left ventricle and is then pumped out of the heart through the aorta.
• The aorta branches to form arteries which transport oxygenated blood to all the body tissues.
• Exchange of gases and nutrients occurs in the body cells of an organ.
• The blood that is transported out of the organ by the vein is deoxygenated blood.
• The blood from the veins in all body tissues is transported into the vena cava and then enters into the right atrium of the heart.

  

  Systemic circulation

• The main function of systemic circulation: to transport oxygenated blood from the heart to all the body tissues.

  

  Pulmonary and Systemic Circulation

SPM Biology 10 Transport (Part 5)

SPM Biology 10 Transport: Functions of Haemolymph in Transport

Circulatory system of insect

1. In insects, the blood does not flow in closed blood vessels.
2. Blood is pumped out of the heart to fill the spaces between the body cells.
3. The blood of the insect which mixes with the tissue fluid around the body cells is called haemolymph.
4. Exchange of materials between haemolymph and body cells occurs by simple diffusion.
5. O₂ and CO₂ are not transported by haemolymph. They are transported through the tracheal system.

SPM Biology 10 Transport (Part 4)

SPM Biology 10 Transport: Platelet, Plasma and the Functions of Blood

Platelet

• Platelets are fragments of larger cells in the bone marrow called megakaryoytes.
• They have no nucleus.
• They are involved in blood clotting.

  

  Platelet

Plasma

1. Plasma is a pale yellowish liquid consisting of 90% water and a large number of dissolved substances, such as :

• Digested food materials: glucose, amino acids, fatty acids, etc.
• Excretory products: urea, uric acid, etc.
• Mineral in the form of ions: calcium, sodium, potassium, etc. and vitamins.
• Dissolved gases.
• Plasma proteins such as albumin, globulin and fibrinogen.
• Hormones.

2. Blood plasma without plasma proteins (albumin, globulin, etc.) is called blood serum.

Composition of blood

Functions of blood

1. Transport of oxygen

• Blood transport oxygen in the form of oxyhaemoglobin.
• In the alveolus, the partial pressure of O₂ is higher than the partial pressure of O₂ in the blood capillary.
• Hence, O₂ diffuses out from the alveolus into the blood capillary around the alveolus by simple diffusion.
• In the blood, O₂ combines with haemoglobin in the erythrocyte to form oxyhaemoglobin.
• O₂ is transported in the form of oxyhaemoglobin to the body cells which lack of O₂.
• At the body cells, oxyhaemoglobin breaks down to release the O₂ to the body cells for cell respiration.

  

  Formation of haemoglobin

2. Transport of carbon dioxide

• CO₂ is transported by the blood in 2 main forms: Ion bicarbonate and carbaminohaemoglobin.
• CO₂ is transported from the body cells to the lungs to be removed during exhalation.
•  In the body cell, as a result of respiration which release CO₂, the partial pressure of CO₂ is higher then in the blood capillary.
• In the blood capillary, CO₂ dissolves in the blood plasma to form hydrogen carbonates ion and is transported in the blood plasma to the lungs.
• At the lungs, enzyme changes the hydrogen carbonate ion to CO₂ again.
• The CO₂ then diffuses out of the blood capillary into the alveolus to be removed during exhalation.
• CO₂ can also be transported in the form of carbaminohaemoglobin which is then transported in the erythrocyte to the lungs.
• At the alveolus, carbaminohaemoglobin breaks down to release the CO₂ which then diffuse into the alveolus to be expelled out during exhalation.

  

  Transport of carbon dioxide

3. Transport of digested food, vitamins and minerals

• Plasma transport digested food such as simple sugars, amino acids, fatty acids, glycerol, vitamins and dissolved minerals.
• Simple sugars, amino acids, minerals and vitamins B and C are absorbed into the blood capillaries in the villus of the ileum.
• These nutrients are then transported in the plasma from the ileum to the liver through the hepatic portal vein, then to the heart and subsequently to the whole body for usage or storage.
• Fatty acids, glycerol, vitamins A, D, E, K diffuse into the lacteal of the villus and are transported from the ileum to the lymphatic system, then back into the circulatory system through the left subclavian vein. The food materials are then transported in the plasma to the whole body.

4. Transport of nitrogenous waster products

• Nitrogenous wastes such as urea are by products of protein metabolism.
• Urea, uric acid. cretinine, bilirubin and ammonium ions are transported to the kidneys to be excreted.

5. Transport of hormones

• Endocrine glands secrete hormones into the bloodstream which are then transported by the plasma to the target organs.
• For example, the insulin hormone is transported by the blood plasma from the pancreas to liver where it acts.

6. Transport of heat

• Heat is produce during cell respiration which occurs actively in the muscles and liver.
• The heat is distributed evenly throughout the whole body by the circulatory system.
• Excess heat can be removed by transporting it to the skin and the lungs by the blood so that the heat is dissipated.

7. Transport of water

• Water is universal solvent. It acts as a medium for all chemical reactions to take place in the body.
• The blood transports water to the whole body to regulate the equilibrium of water and osmotic pressure in the body.

STPM Biology Biological Molecules (Part 16)

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STPM Biology Biological Molecules (Part 15)

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STPM Biology Biological Molecules (Part 14)

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SPM Biology 10 Transport (Part 3)

SPM Biology 10 Transport - Leukocyte

Composition of human blood
Leukocyte (white blood cell)
1. Has a nucleus.
2. Has no fixed shape.
3. Larger size than erythrocyte.
4. The number of leukocytes in the blood is < than erythrocytes.
5. Function of leukocyte: to protect the body from diseases.
6. There are 2 types of leukocytes:

• Granulocyte
• Agranulocyte

Leukocytes

Granulocyte (granular cytoplasm)

1. Have granules in the cytoplasm.

2. Have lobed nucleus.

3. Are formed in red bone marrow.

4. There are 3 types of granulocytes:

• Neutrophil
• Eosinophil
• Basophil

5. Neutrophils are phagocytes which carry out phagocytosis to engulf and digest invading bacteria.

6. Eosinophils function in regulation the allergic responses.

7. Basophils produce heparin which prevents the blood from clotting.

Agranulocytes (nongranular cytoplasm)

1. Have no granules in the cytoplasm.

2. There are 2 types of agranulocytes:

• Lymphocytes
• Monocytes

3. Lymphocytes have a large spherical nucleus with little cytoplasm. They are formed in the lymph nodes of the lymphatic system. They produce antibodies to protect the body against diseases.

4. Monocytes has a kidney-shaped nucleus. They are formed in the bone marrow. They are phagocytes which carry out phogocytosis.

SPM Biology 10 Transport (Part 2)

SPM Biology 10 Transport - Erythrocyte

1. The circulatory system in human and animals consists of:

• Blood
• Blood vessels
• Heart

2. The medium of transport in human and animal = BLOOD

Composition of human blood

1. Blood = a connective tissue in liquid form.

2. The human blood is made up of:

• 55% plasma
• 45% blood cells

3. Plasma is the liquid part of the blood. It is pale yellowish in colour and contains various dissolved substances.

4. There are 3 types of blood cells:

• Erythrocytes (red blood cell)
• Leukocytes (white blood cell)
• Platelets

Blood composition

Erythrocytes (red blood cell)

Erythrocyte (red blood cell)

1. Biconcave disc-shaped.

• Increases the TSA/V ratio to facilitate the exchange of gases by diffusion across the membrane.

2. Has an elastic membrane.

• Enables the erythrocyte to change its shape, so that it an squeeze through the narrow blood capillary.

3. Matured erythrocytes does not have nucleus.

• Enables the erythrocyte to contain more haemoglobin to carry more oxygen.

4. Erythrocytes are produces in the bone marrow.

5. Erythrocytes survive for about 120 days and are then destroyed in the spleen and liver.

6. Each erythrocyte contains haemoglobin, a respiratory pigment containing iron and causes the blood to be red in colour.

7. Haemoglobin is responsible for:

• transport oxygen (oxyhaemoglobin)
• transport carbon dioxide (carbaminohaemoglobin)

8. When erythrocytes are destroyed, the by-products are iron and the bile pigment called bilirubin. The accumulation of the bilirubin in the body can cause jaundice, that is yellowing of the eyes and skin. While the iron will be reused to produce new haemoglobin or excreted from the body.

SPM Biology 10 Transport (Part 1)

SPM Biology 10 Transport

Transport system of human

The Importance of transport system in multicellular organisms

1. All the chemical reaction take place in the cells to ensure the survival of the cells.

2. Hence, every cell in an organism must be able to obtain all the substances it needs (nutrients, oxygen, etc.).

3. Besides, the cell must be able to remove the waster products such as carbon dioxide and urea from the cell.

4. Exchange of gases and substances occur across the plasma membrane of the cells by diffusion.

5. Unicellular organisms (Amoeba sp., etc.) can easily and rapidly obtain the cell requirements and removing the waster products by diffusion, without having any special structure to transport these substance. WHY? Because they:

• Small in size.
• Have a large total surface area to volume (TSA/V) ratio.

6. The smaller the size of the object, the larger the TSA/V ratio, the higher the rate of diffusion.

Surface-to-volume ratio

7. Multicellular organisms cannot depend on diffusion alone to gain the cell requirements. WHY? Because they:

• Large body size.
• Have a small TSA/V ratio.
• The amount of cell requirements and metabolic waster products increases.
• The cells are located further in the body.

8. To overcome these problem, multicellular organisms (human, animals, etc.) need special transport system:

• to transport the nutrients to all the body cells.
• to remove the metabolic waster products from the body cells.

9. The transport system in humans and animals = circulatory system.

10. In plants, the transport system is the vascular tissues which consist of xylem tissues and phloem tissues.

STPM Biology Biological Molecules (Part 13)

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STPM Biology Biological Molecules (Part 12)

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STPM Biology Biological Molecules (Part 11)

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STPM Biology Biological Molecules (Part 10)

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STPM Biology Biological Molecules (Part 9)

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SPM Biology 3 Movement of Substances Across the Plasma Membrane (Part 3)

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STPM Biology Biological Molecules (Part 8)

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STPM Biology Biological Molecules (Part 7)

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SPM Biology 3 Movement of Substances Across the Plasma Membrane (Part 2)

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SPM Biology 3 Movement of Substances Across the Plasma Membrane (Part 1)

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STPM Biology Biological Molecules (Part 6)

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STPM Biology Biological Molecules (Part 5)

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STPM Biology Biological Molecules (Part 4)

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STPM Biology Biological Molecules (Part 3)

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SPM Biology 15 Variation (Part 2)

SPM Biology 15 Variation (Part 2)

Mutation 

Mutation is a spontaneous change in genetic composition of a cell. It can occur in somatic cells or gametes. 

Mutation is caused by:

1. Gene Mutation
2. Chromosomal Mutation

Types of mutations

Gene Mutation

Gene mutation involves changes to the bases in the DNA of one gene. For example:

• sickle cell anemia (mutation to gene that causes red blood cells to become sickle-shaped).
• albinism (mutation to gene that control the production of melanin pigment).
• haemophilia.

Gene mutation

Chromosomal Mutation

Changes in the structure or the number of chromosomes are called chromosomal mutation. Examples of the alterations in the structure of some parts of the chromosome are duplication, deletion, translocation and inversion. Chromosomal mutation can happen during mitosis and meiosis when chromosomes are condensed and pulled apart. It also occurs during crossing over. 

Chromosomal Mutation

Mutagens are the substances that can also cause the mutation or increase the rate of mutation. For instance:

• x-ray
• ultraviolet radiation
• chemical substances such as nitrous acid, formaldehyde, food preservatives, pesticides, drugs and some components in cigarette smoke.

SPM Biology 15 Variation (Part 1)

SPM Biology 15 Variation (Part 1)

Variation

Variation means the differences between the individuals of the same species. There are two types of variations, namely continuous variation and discontinuous variation.

In continuous variation, the differences are slight and they grade into each other. They are usually no limit on the value and tends to be quantitative. They are considerable influences of the environment. For instance, height, body weight, and skin colour. The shape of the continuous variation's graph is normal distribution.

In discontinuous variation, the differences are discreet and clear cut. They do not merge into each other. They are controlled by one, two or very few genes and tends to be qualitative. For examples, type of hair, type of earlobes, tongue rolling, fingerprints, and blood group. The shape of discontinuous variation's graph is discreet distribution.

Comparison between Continuous and Discontinuous Variation

What are the factors that cause variation?

1. Environmental Factors

Change the phenotypes of plants resulting in acquired characteristics which cannot be inherited. It also determines the survival of plants. Continuous variation in humans are also the product of environmental influence.

Environmental factors

2. Genetic Factors

In prophase I, pairing of homologous chromosome will form chiasma. Chromosomal crossing-over happens in the chiasma and there are exchange of genes between the two chromatids of the homologous chromosome. In metaphase I, chromosomes are aligned randomly and various gametes that contain different pairs of chromosomes are formed. In anaphase II, chromatids are separated and gametes with a variety of combinations of genes are produced.

Homologous chromosomes

Gametes from different parents are fertilised randomly and cause genetic variations. Gametes with diverse combinations of homologous chromosomes are fused together to form a zygote which intern produces greater variety of gene combinations.

The traits of an organism are controlled by a single pair of alleles or by several pairs of alleles. The traits that are controlled by several pairs of alleles are influenced by the environment.These alleles interact with one another and with the environment. For instance, the colour of the skin is affected by genetic factors. The colour of the skin of an individual become darker when exposed to sunlight. So, the change of colour of the skin is affected by the interaction between genetic factors and environmental factors on continuous variation.

Variation is important to a species because only the individuals best adapted to their environment ted to survive and transmit their genetic characteristic to the offspring. From time to time, there will be changes in the individual of a particular species, with the better adapted ones increasing in population. This is called the "Survival of the Fittest" or "Natural Selection".

Variation

Free Online Korean Language Learning (Part 4)

Learn Korean

Source: Korea Tourism Organization

Learn Korean is a FREE site for learning Korean language provided by the Korea Tourism Organization. Here you can choose between a beginner and intermediate section, also a program called Korean expressions for travelers for not only learning useful Korean conversation but also travelling in Korea. 

Beginner

Source: Korea Tourism Organization

The Beginner Korean program is provided by KBS World Radio. The topic of understanding the Korean language will introduce the alphabet and basic grammar, and some simple expressions will be taught within the 30 chapters provided.

Intermediate

Source: Korea Tourism Organization

The intermediate section called Korean Language Adventure have been developed in the theme of travel and adventure, allowing us to take a virtual journey to Seoul and the famous tourist destinations. There are 30 units of the most popular tourist destination which you can selectively choose either one unit to study. However, you need to signup a VisitKorea membership to view all the units.