Life sciences Grade 10 CAPS: structured, clear, practical Helping teachers unlock the power of NCS KNOWLEDGE AREA: Life at the molecular, cellular and tissue level Topic 1: Chemistry of life Inorganic compounds

CAPS SPECIFIC AIMS 1. Knowing Life Sciences 2. Investigating Phenomena in Life Sciences 3. Appreciating and Understanding the History, Importance and Applications of Life Sciences in Society

Specific Skills Access information Apply knowledge in new contexts Select key ideas Recall information Describe knowledge of NS Build a conceptual framework Organise or reorganise knowledge Write summaries Develop flow charts and mind maps Recognise patterns and trends Apply knowledge in new contexts Use knowledge in a new way Analyse information/data Critically evaluate scientific information Recognise relationships between existing knowledge and new ideas Identify assumptions Categorise information

Chemistry of life Summary layout Minerals Inorganic compounds

Elements Remember all compounds are made up of elements. Elements are pure substances. Elements bond to form compounds. There are two types of compounds: organic and inorganic. Inorganic compounds do not contain the element carbon 12, some examples of these compounds are water, minerals and gases like carbon dioxide. Organic compounds contain the element carbon 12 and examples of these compounds are carbohydrates, proteins and lipids.

Mineral SALTS Minerals are inorganic substances that are required by living organisms (plants and animals). Minerals can be divided into two groups: Micro-elements: required in small quantities Macro-elements: required in large quantities

Maintains osmotic balance in plants Reduced plant growth Functions of some minerals /MACRO ELEMENTS and their deficiency diseases. Mineral Function Deficiency Sodium (Na) Plants Maintains osmotic balance in plants Reduced plant growth Animals Has a role in the functioning of nerves and muscles Regulates the secretion of HCl in the stomach Muscle cramps Potassium (K) Needed for: Photosynthesis Protein synthesis, activation of plant enzymes Regulation of the stomata Lower drought resistance Excessive water lose disease Regulation of : Blood pressure, nerve functions, muscle control, cellular respiration Low oxygen levels Muscular cramps Lung failure

Used for the formation of the middle lamella of cell walls Functions of some minerals/MACRO ELEMENTS and their deficiency diseases Mineral Function Deficiency Calcium (Ca) Plants Used for the formation of the middle lamella of cell walls Also maintains the permeability of cell walls Poor plant growth Growing parts of plant die Animals Required for bone and teeth formation. Used in blood clotting In children causes rickets Phosphorous (P) needed for cell membrane formation and for the formation of nucleic acids Used for the formation of ATP Leaves fall off prematurely Brown spots develop on leaves Used for the formation of cell membranes, nucleic acids, ATP and bone and teeth Rickets in children

Functions of some minerals/MICRO ELEMENTS and their deficiency diseases Iron (Fe) Plant Used in the formation of chlorophyll Leaves become yellow due to the lack of chlorophyll. This is called chlorosis Animals Used for the formation of haemoglobin anaemia Iodine (I) Plants Used in photosynthesis Photosynthesis decreases causing a decrease in growth and death of the plant Used in thyroxin formation Causes enlargement of the thyroid gland. This disease is called goiter.

Functions of some minerals/MACRO ELEMENTS and their deficiency diseases Nitrogen (N) Plants Used by plants for the formation of amino acid, nucleic acids and chlorophyll chlorosis Animals Required for protein synthesis and nucleic acids Kwashiorkor in children Magnesium (Mg) Used to make the central atom of chlorophyll molecule Chlorosis Used for bone and teeth formation and for nerve and muscle functioning Muscle cramps

Something for you to do. 1. Explain what is meant by… 1.1 osmosis 1.2 protein synthesis 2. Describe … 2.1 chlorophyll 2.2 haemoglobin 2.3 amino acids 3. Explain why chlorosis occurs when there is an iron and nitrogen deficiency. 4. Name the gland that secretes thyroxin.

solution 1.1 osmosis is the movement of water from a region of high concentration to a region of low concentration across a differentially permeable membrane. 1.2 protein synthesis is the process during which proteins are made. 2.1 chlorophyll is a green pigment found in plants and is used to give plants the green colour and trap sunlight. 2.2 haemoglobin is a red pigment found in the red blood cell, its function is to give blood the red color and to transport gases. 2.3 amino acids are the building blocks of proteins. 3. Both iron and iodine is used to make chlorophyll, if these minerals are deficient then the plant cannot make enough chlorophyll and the leaves will lose their green colour. 4. Thyroid gland

The need for fertilizer in over used soil In order for plants to grow they need nutrients. These nutrients come from both the soil and air. Nutrients enter the soil when dead plants and animals decay. In order to achieve this richness of soil, decomposition should be encouraged. Farmers can achieve this in two ways. To leave the soil fallow To plough back dead plants into the soil.

Fallow means: if the land is used constantly there is no time for the land to be left fallow or for natural nutrient recycling to occur. Therefore the soil may become very infertile. The farmer may use synthetic fertilizers to replace the lost nutrients. These fertilizers may contain phosphates and nitrates. When it rains these fertilizers may be washed out into to the rivers. The nutrient content of the river increases. This increased nutrient content causes a rapid growth of plant and algae in the water. This is called eutrophication.

The increased plant growth especially the algae covers the surface of the water, preventing sunlight from reaching the plants lower down in the water. These plants will die and the aquatic organisms that depend on these plants will also die. The dead plant and animal matter begin to rot and attract bacteria to the water. The increased bacteria uses more oxygen and this decreases the oxygen content of the water. This results in more plants and animals dying.

water Water can exist naturally in three states or phases: solid, liquid and gas. In its solid state it exists as ice found in the polar ice caps, as a liquid it is called water and is found in the rivers, lakes and oceans and as a gas it is called water vapour and occurs in the atmosphere. Importance of water: 1. The human body is made up of 60-75% water. 2. 70-95% of the cell is made up of water. 3. Water makes life on Earth possible.

STRUCTURE OF water: One molecule of water is made up of two hydrogen atoms and one oxygen in the arrangement shown below.

Functions of water 1. It is used during digestion to break down large insoluble substances into smaller soluble substances. 2. It is a medium for all chemical reactions in the cell. 3. It is used to transport food along the alimentary canal and mineral salts in plants. 4. Dissolve the waste substance in the body to form urine and sweat.

Terminology Elements are pure substances. Compounds are made up of two or more elements. Inorganic compounds are compounds that do not contain the element carbon 12. Organic compounds are compounds that contain the element carbon 12. Minerals are inorganic substances that are required by living organisms. Macro-elements are elements that are required in large quantities by living organisms. Micro-elements are elements that are required in small quantities by living organisms. Eutrophication is the rapid growth of the population of living organisms, usually aquatic plants , due to increased supply of nutrients.

Question 1 The mineral required for the prevention of muscle cramps is… A. K B. Na C. Ca D. Fe

Question 2 The mineral that is required for the formation of amino acids… A. K B. Na C. Ca D. N

Question 3 A deficiency of this mineral results in Goitre. A. K B. I C. Ca D. N

Question 4 Lack of iron results in a deficiency disease in plants called… A. Kwashiorkor B. Goitre C. Anaemia D. chlorosis

Question 5 A lack of this mineral results in lower drought resistance. A. K B. I C. Ca D. N

Question 6 The mineral that is used for formation of nucleic acids and the chlorophyll molecule is called… A. K B. I C. Ca D. N

Question 7 In order for a child to have good strong bones and teeth, his/her diet must be rich in the following minerals A. Ca and P B. N and I C. Fe and K D. Na and Mg

Question 8 To prevent chlorosis the soil must contain the following nutrients. A. Mg, I, Fe B. Na, P, K C. Fe, N, Mg D. I, P, K

Question 9 Phosphorous is used for the formation of… A. Central atom of the chlorophyll molecule. B. Nucleic acids C. Amino acids D. Thyroxin

Question 10 The central atom of the chlorophyll molecule is… A. Mg B. I C. Ca D. N

Question 11 The mineral that is the component of hemoglobin is… A. K B. I C. Ca D. Fe

Question 12 The mineral that is required for the middle lamella of cells and is used in the clotting of blood is… A. K B. I C. Ca D. N

Question 13 The pigment that is used for the transport of gases is called… A. Haemoglobin B. Chlorophyll C. Thyroxin D. None of the above

Question 14 The hormone that is secreted by the thyroid gland is called… A. Haemoglobin B. Chlorophyll C. Thyroxin D. None of the above

Question 15 Mineral that is found as the central atom of the chlorophyll molecule and for functioning of nerves and muscles. A. K B. I C. Fe D. Mg

Question 16 The inorganic substance that is involved in transport. A. water B. Haemoglobin C. Xylem D. thyroxin

Question 17 Minerals that are needed in small quantities are called… A. Micro-elements B. Macro-elements C. Mega-elements D. None of the above

Question 18 Mineral that are needed in large quantities by organisms… A. Micro-elements B. Macro-elements C. Mega-elements D. None of the above

Question 19 In order for a child to be free from rickets and kwashiorkor, his diet must be rich in… A. Ca and N B. K and P C. Ca and P D. N and K

Question 20 The element required for the formation of the pigment found in the red blood cell is… A. I B. K C. Fe D. P

solution B D A C

solution D C A B