the respiratory system

the respiratory system
windpipe air sac lung

(a) Circle the correct words to complete the following sentences. bone (i) The windpipe is kept open by rings of fibre cartilage bronchi (ii) The windpipe divides into two . bronchioles 1 . 1

(b) Name the type of blood vessel which surrounds the air sacs. ……………………………………………………………………………………………… (c) Describe the self-cleaning mechanism of the lungs. 1

……………………………………………………………………………………………… ……………………………………………………………………………………………… ……………………………………………………………………………………………… 2

2. Increasing carbon dioxide concentration in the atmosphere is responsible for environmental changes. (a) (i) Give one reason why the carbon dioxide concentration in the atmosphere is increasing. ………………………………………………………………………………………. (ii) Give two examples of environmental changes that have been linked to increasing carbon dioxide concentration in the atmosphere.

b) The upper layer of the atmosphere contains a gas which protects us from harmful solar radiation. Name this gas. 1 2

……………………………………………………………………………………………… 3. Burning plastics produce gases that are harmful to humans. Complete the table below. Plastic Harmful gas produced when plastic burns hydrogen cyanide Effect of harmful gas on the human body damages the brain and nervous system stops blood from carrying oxygen

polystyrene

polyvinylchloride (PVC)

hydrogen chloride 3
4. An investigation was carried out to find out how light affects where woodlice are found. Two woodlice were placed in a tray with a plastic lid. Half of the lid was black to keep out light. The other half was clear to let in light. After 1 minute the number of woodlice in each half of the tray was recorded. lid tray woodlouse Results Number of woodlice in light 1 Number of woodlice in dark 1

Marks KU PS

The investigation was fair but could be improved to make the results more reliable. Suggest two improvements. 1 ………………………………………………………………………………………………… 2 ………………………………………………………………………………………………… 2

 

5. The boxes below describe some properties of materials. 1 supports a heavy load without breaking 4 bends without snapping Which box describes (a) flammability? (b) thermal conductivity? (c) flexibility? (d) hardness? Box number ………………. Box number ………………. Box number ………………. Box number ………………. 2 allows heat to pass through 5 catches fire easily 3 allows electricity to pass through 6 resists damage by impact
6. Use the information in the passage below to answer the questions. Lactose intolerance is the inability to digest lactose, the main sugar in milk. Normally, the cells that line the small intestine produce an enzyme called lactase. Lactase digests the milk sugar by breaking it down into simple substances, such as glucose, that can be absorbed into the blood. If the small intestine is not producing lactase, the body cannot digest lactose. This leads to symptoms of lactose intolerance, such as nausea and diarrhoea. Many people with lactose intolerance also suffer from bloating, which is a build up of gas in the intestine caused by the action of bacteria on undigested lactose. Most babies produce high levels of lactase, enabling the digestion of milk. After the age of 2 years, the body begins to produce less lactase. In some individuals, the body fails to produce enough lactase, leading to the development of lactose intolerance in older children and adults. The most common diagnostic tests for this condition are known as the lactose tolerance test and the hydrogen breath test. Both tests involve giving the patient a drink with a high concentration of lactose. For the lactose tolerance test, blood samples are taken to measure the blood glucose level. This shows how well lactose is being digested. For the hydrogen breath test, breath samples are analysed at regular intervals. Raised levels of hydrogen indicate the presence of undigested lactose in the intestine. These tests are not given to babies and very young children as the high lactose drink may cause diarrhoea and severe dehydration. Many doctors simply recommend changing the child’s diet from dairy milk to a non-dairy alternative, such as soya milk. (a) State two symptoms of lactose intolerance. ……………………………………………………………………………………………… (b) Why do most babies produce high levels of lactase? ……………………………………………………………………………………………… (c) Why does lactose intolerance develop in some older children and adults?
(d) Give one way in which the lactose tolerance test and the hydrogen breath test (i) are similar. …………………………………………………………………… ……………………………………………………………………
Gilding

Red

Key Cartridge Muntz zinc copper

The table below shows some of the properties of the different types of brass. Tensile strength (MPa) 245 280 357 378 Hardness (units) 52 64 72 80

Type of brass Gilding Red Cartridge Muntz

(a) What conclusion can be drawn about the composition of brass and its hardness? ……………………………………………………………………………………………… ……………………………………………………………………………………………… (b) Predict the tensile strength of brass which contains 75% copper. ……………………………… MPa 1 1
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