Eolaíocht J.C.E. D.Mac an Aircinn
Cells
A living thing is called an organism, e.g. a dog is an organism, so is a daffodil. The characteristics of living things are:
Feeding / living things need food to get energy.Movement / living things move either their whole body (animals) or parts of the body (plants).
Respiration / process by which organisms obtain their energy.
Sensitivity / organisms are able to respond to changes in their surroundings.
Excretion / living things get rid of wastes they have made in their bodies which would be harmful
Reproduction / living things are able to make more of their own kind..
Growth / living things get bigger.
There are many types of animals. They are important in agriculture as food; in medicine because they cause disease; in the fishing industry and as a source of pleasure and recreation. There are many types of plants. Plants form the first link in all food chains and are in important source of oxygen. A food chain is a feeding relationship between organisms. Plants are important in agriculture, industry, medicine and as a source of pleasure, e.g. gardening. Plants differ from animals in a number of ways, e.g. feeding and movement.
You must be able to classify living things into plants or animals, vertebrates or invertabrates. One of the investigations involves going out into a habitat (say school field) and identifying five plants and five animals. The animals must be further identified as vertabrates or invertabrates. Below are examples of keys used to identify the most common plants found in grassland areas.
Vertabrates – animals that have back bones, e.g. rabbit, mouse, snake. Invertabrates – animals that do not have backbones, e.g. earthwork, spider and woodlouse.
Binary key to plants of the school field (using leaves)
The following is a key to the most common plants of the school field, done in YES/NO style. To identify a plant start a 1 answer the question and do what is says.
You must look at the whole plant for this key to work not separate leaves.
- Leaves long, thin and flat, like blades?
No / Grass
Go to 2
- Leaves ribbed from stem to tip?
No / Go to 3
Go to 4
- Leaves long and thin?
Rat’s tail plantain
- Leaves in 3 round parts?
No / White Clover
Go to 5
- Leaves in 3 round parts and pointed at the top?
- Small leaves on trailing stems?
No / Go to 7
Go to 8
- Hairy leaves?
Speedwell
- Leaves radiate for the centre of the plant?
- Round leaves?
Dandelion
Binary key to plants of the school field (using flowers)
You can identify the same plants using their flowers instead of leaves, obviously only when they are flowering. Like with the leaves key start at 1, answer Yes or No and then do what it says. You must look carefully.
- Flowers very small and spiky – no petals?
NO / Grass
Go to 2
- Flowers green, no petals, brown stamens all round them?
NO / Go to 3
Go to 4
- Flowers short and rounded?
Rat’s tail plantain
- Lots of petals arranged in a rosette?
NO / Go to 5
Go to 6
- Petals all yellow?
Daisy
- Petals in a pom-pom shape and white?
NO / White clover
Go to 7
- Petals in a pom-pom shape and purple?
NO / Red clover
Go to 8
- Petals blue?
Mouse-ear chickweed
The two keys here help you to identify the 9 most common plants found on school fields. Of course there are other plants to be found that this key does not identify. There is always the possibility that you could not identify a plant because you did not use the key correctly.
All living things are made of cells which are the building blocks of organisms. To study cells we use the light microscope.
Eyepiece – allows you to view the object to be magnified.
Objective lens – magnifies the specimen.
Course focus – lowers and raises the microscope to focus the object.
Fine focus – allows accurate focusing at high power.
Stage – holds the glass slide in position.
Light source – bulb or mirror allow the object to be illuminated.
Exp: Preparing a slide involves the following steps.
- A drop of water is placed in the centre of a clean dry slide.
- A small piece of onion skin is peeled off and placed flat on the slide in the water using a forceps.
- A drop of Iodine is put on the specimen.
- A coverslip is lowered carefully at angle to cover the specimen and avoid air bubbles getting trapped.
- The onion is examined first at low power and then at higher powers.
Below are diagrams of typical plant and animal cells.
All cells consist of the following parts:
Part / FunctionCytoplasm / contains dissolved substances, jelly-like
Cell Membrane / controls the entry and exit of substances in/out of the cell
Nucleus / controls the activities of the cell
Vacuoles / store food, large in plants small in animals
Cell Wall / give strength to the cell, plants only.
Chloroplasts / help plants make their food, plants only
Plant cells differ from animal cells in the following ways: large vacuoles, cell walls and chloroplasts. . Groups of similar cells with a special function form a tissue. e.g. muscle. Several tissues grouped together form organs, e.g. heart. When a group of organs work together to perform a function they make up a system, e.g. the circulatory system
Growth results from cells dividing.
Nutrition and Digestion
Food is needed for energy, growth, repair and protection against disease in the body. Food is made up of chemicals called nutrients A food's energy value is how much energy that can be obtained from the food. A balanced diet consists of the correct amounts of each type of food .
The main nutrients are:
Carbohydrates (sugars) are found in sugar rich foods, e.g. honey, sweets, and jam. They provide energy and fibre (needed for muscles of the bowel to work properly [roughage]), They contain carbon, hydrogen and oxygen and are made of single sugar units which can be joined together in long chains. Starch is a long chain sugar and glucose is simple single sugar. e.g. starch in bread. To test a food for starch, add brown iodine solution. If it turns a blue/black colour then starch is present.with water and roughage
Proteins e.g. fish contain carbon, nitrogen, oxygen, hydrogen and sometimes sulphur. They are found in fish and meat. They contain chains of amino acids joined together. They are used for building new cells. e.g.muscle and bone.
Fats e.g. butter contain carbon, hydrogen and oxygen and are made of units of fatty acids and glycerol. They provide heat insulation and energy.
Vitamins e.g. vitamin D in milk are chemicals needed in small amounts to protects us against disease. For example vitamin A is needed for healthy eyes and skin and is got from carrots and cod-liver oil.
Minerals e.g. calcium for bones inorganic elements needed in small amounts for good health. Iron for example is needed to carry oxygen in the blood. Calcium is needed for bone
Roughage is also required to keep the digestive system in tone got from green vegetables (fibre).
Exp. Testing a food for starch
1.Add 2cm of starch solution or food to a test tube.2. Add 2-3 drops of iodine (red/brown)
3. If a blue/black colour is obtained. then starch is present
Exp. Testing for proteins
1.Add milk or dissolve the food to be tested to a test tube (2cm level)
2.Add an equal amount of sodium hydroxide
3.Add a few drops of copper sulphate solution.
4.If a violet colour is obtained then the food contains protein
Exp. Testing for glucose.
1.Add 2cm3 of glucose or the food to a test tube.2.Add 2cm3 of benedict's reagent (blue) to the test tube
3.Set up as shown in the diagram and heat.
4.If a red/orange colour is obtained then the food contains glucose.
Exp. Testing for fats
Rub margarine or the food on brown paper.
Allow to dry and compare.
Put a drop of water on another piece of brown paper
A translucent spot indicates that fats are present
The human digestive system has the following parts and functions.
Human Nutrition
INGESTION / taking of food into to the mouth
DIGESTION / break down of food into small soluble pieces
ABSORPTION / taking in of useful food into the bloodstream
ASSIMILATION / use of food for growth, repair and energy
EGESTION / removal of unused food from the body.
Stages of digestion / Mouth Chewing and saliva
Stomach: Churning, gastric juices, acid to kill germs
Small intestines: digestive juices from pancreas
Results of digestion / Carbohydrates glucose
Proteins amino acids
Fats fatty acids and glycerol
An enzyme is a biological catalyst, it speeds up chemical reactions without being used up
Exp. To show the action of an enzyme
1.In test tube A add starch solution, iodine, and tap water, this blue/black solution is the control
2.In test tube B add starch solution, iodine and saliva.
3.Leave both for several minutes at 37oC.
4.The mixture in tube B goes colourless
5.The mixture in tube A does not change.
6.The enzyme in saliva breaks down starch.
Note: Saliva contains the enzyme amylase
Exp: To show food contains energy (chemical energy)
- Set up as shown in the diagram.
- Record the temperature of the water at the start.
- Light the cracker with a match and hold it under the test tube with a tongs.
- After a few minutes record the temperature of the water.
- A rise in temperature in the water confirms chemical energy in the food was converted into heat energy.
There are four types of tooth.
1 . Incisors these teeth are used for cutting and biting food.
2. Canines these teeth are used for tearing food.
3. Premolars these teeth are used to grind food.
4. Molars these teeth are used to grind food.
Plaque and sugars cause tooth decay
Respiration and Breathing
During breathing, oxygen gas is taken into the body and carbon dioxide gas and water vapour are released. The human breathing organs are the lungs. The diaphragm and intercostal muscles used in breathing. Inspiration is breathing in and expiration is breathing out. Expired air contains more carbon dioxide than inspired air. This carbon dioxide is made in the cells during respiration. Carbon dioxide turns lime water milky. Smoking can damage your breathing system by damaging the bronchiole lining, reducing resistance to bronchitis and lung cancer, stunting the growth of a baby during pregnancy and heart strain due to carbon monoxide gas in the smoke.
The bell jar with the balloons represents the breathing system, the balloons are the lungs, the rubber sheet acts like the diaphragm. You must know how it works.
Insects have a system of air holes called spiracles to take in air. Gaseous exchange takes place through the alveoli ( air sacs covered by a network of blood capillaries where carbon dioxide diffuses out to the lungs and oxygen diffuses into the blood ).
Exp. To show expired air contains more carbon dioxide than inspired air.
1.Set up two test tubes as shown in the diagram
2.Breath in through x in test tube A
3.Breath out through Y in test tube B
4.Repeat until the lime water in one tube goes milky
5.The lime water in B turns milky much quicker showing that exspired air contains more carbon dioxide.
Respiration is the release of energy from food:
Glucose + Oxygen Carbon dioxide + Water + Energy
C6H12O6 + 6O2 6CO2 + 6H2O +energy.
Exp. To show carbon dioxide is produced during respiration.
Set up the apparatus as shown in the diagram. See diagram 1.
The lime water in A goes milky
This is because the woodlice are respiring and carbon dioxide turns lime water milky
Exp. To show heat is produced during respiration.
Fill two flasks one with germinating peas and a second (a control) with dead boiled pea seeds. Seal both with cotton wool and put a thermometer in each.
Record the temperature of both flasks every day for one week.
The temperature rises sharply in the flask with the germinating peas which shows heat is produced during respiration.
The Circulatory System and Excretion
Arteries carry blood away from the heart. Veins carry blood to the heart. Capillaries link arteries to veins. Arteries have thick walls, no valves, blood at high pressure, are deep in the body and have a small lumen. Veins have thin walls, valves to prevent backflow of blood, blood at low pressure, are near the surface and have a large lumen.
The functions of the blood are: (a) transport of food oxygen to body cells, carbon dioxide to the lungs and excretory products to the kidneys, (b) defence against disease with white blood cells destroying bacteria or producing antibodies to kill bacteria and blood clotting to stop blood loss and stop invading germs.
The blood is made up of blood plasma with red blood cells to carry oxygen, white blood cells to fight germs, and platelets to help blood to clot. Substances pass in/out of the blood through the thin walls of the capillaries.
How the heart works1.Blood from the body goes in to the right atrium via the vena cave
2.At the same time blood from the lungs fills the left atrium.
3.The atria contract, the bicuspid and tricuspid valves open and the ventricles fill up.
4.The ventricles contract, the tricuspid and bicuspid valves close, the semi-lunar valves open and blood is pumped into the arteries.
5.Blood from the right ventricle goes to the lungs via the pulmonary vein and blood from the left ventricle goes around the body via the aorta.
Heart disease is caused by smoking, too much fat, stress and lack of exercise.
Heart rate is increased by exercise, escitement, anxiety and smoking. Heart is decreased by rest, clinical shock and certain drugs.
The average human pulse rate (heartbeat) is 72 beats per minuter. This value depends on our fitness and age.
Excretion is the removal of waste products made in the body. The organs of excretion are (a) the lungs getting rid of carbon dioxide and water, (b) the kidneys getting rid of urine and (c) the skin losing water and salts as sweat.
Renal artery : blood with wastes to kidneys
Renal vein : clean blood back to heart
Kidneys: filter blood remove waste
Ureter: carries urine to bladder
Bladder: stores urine
Urethra: carries urine out of the body
The Skeleton and Muscles
The functions of the human skeleton are: a) support, b) movement and c) protection.
A joint is formed where two or more bones meet. There are two types of joints: a) fused joints, e.g. bones of the skull and b) synovial joints, e.g. (i) ball and socket joint (hip), (ii) hinge joint (elbow) and (iii) pivot joint (base of skull). Ligaments connect bone to bone and tendons connect muscle to bone. Leg and arm muscles work as antagonistic pairs i.e. when one muscle contracts the other relaxes, e.g. the triceps and biceps of the arm. If a bone is left in dilute HCl overnight it becomes flexible and rubbery. This is because the mineral content such as calcium has been removed. In a synovial joint the bone are protected from rubbing off each other by a pad of cartilage (gristle) and a lubricating liquid call synovial fluid.
Sensitivity and Co-ordination
Sensitivity is the ability to respond to a stimulus, e.g. light. The five main sense organs the skin, nose, ears, eyes and tongue. Co-ordination is controlled by the nervous system and the endocrine system. The nervous system is made up of the brain, spinal cord and nerves (which are bundles of nerve cells called neurons). Sensory neurons carry impulses to the brain and spinal cord. Motor neurons carry impulses from the brain and spinal cord. The endocrine system is made up of a number of glands which produce hormones. Hormones are chemical messengers and are carried in the bloodstream from the gland to where they are needed e.g. insulin is produced in the pancreas and is needed to control the level of sugars in the blood. A person who cannot produce insulin has the disease diabetes.
Eye parts and their functionaqueous humour / watery filling in front of eye
Vitreous humour / jelly like filling of the eye
Yellow spot / area of sharpest vision.
Optic nerve / carries messages to the brain
Blind spot / area where optic nerve leaves the eye.
cornea / transparent protection for eye
pupil / hole through which light gets to the lens
lens / focuses light on the retina
iris / coloured part of eye. It controls the size of the pupil
retina / the image is focused.. This is the light sensitive area.
Human Reproduction and Genetics