Organisation. AQA Biology topic 2

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1 Organisation AQA Biology topic 2

2 2.1 Principles of Organisation

3 Cells, tissues, organs and systems Basically, all living things are made up of cells A group of CELLS makes up a TISSUE A group of TISSUES makes up an ORGAN A group of ORGANS makes up a SYSTEM A group of SYSTEMS make up an ORGANISM

4 Another example Here s another example in humans: Muscle cells Muscle tissue Organ System Organism

5 2.2 Animal tissues, organs and organ systems

Recap of The Digestive System Match these functions with the parts of the digestive system that do them In here the food is chewed to This tube uses

Bile is produced here Bile is stored here Excess water is absorbed here This organ mixes the food with hydrochloric acid to kill bacteria and also

6 Recap of The Digestive System Match these functions with the parts of the digestive system that do them In here the food is chewed to This tube uses muscle contractions to push the food down start breaking it down. An enzyme (amylase) is also added. Bile is produced here Bile is stored here Excess water is absorbed here This organ mixes the food with hydrochloric acid to kill bacteria and also produces enzymes Food is absorbed into the bloodstream here More enzymes are made here The digestive system is an example of an organ system in which several organs work together to digest and absorb food.

Introduction to Enzymes Enzymes are biological catalysts. They help the reactions that occur in our bodies by controlling the rate of reaction.

7 Introduction to Enzymes Enzymes are biological catalysts. They help the reactions that occur in our bodies by controlling the rate of reaction. An enzyme is basically a large protein molecule made up of long chains of amino acids. These molecules are then folded to create a certain shape. The enzyme s shape helps another molecule fit into it ( lock and key ): This shape can be destroyed ( denatured ) by high temperatures or the wrong ph: Enzyme Substrate

8 The Active Site Active site Enzyme Substrate

9 Enzymes Enzymes work best in certain conditions: Enzyme activity Enzymes are denatured beyond 40 O C Could be protease (found in the stomach) Could be amylase (found in the intestine) 40 0 C Temp ph ph Notice that most enzymes are denatured at high temperatures. Different enzymes work best in different ph conditions.

10 Quiz on the last few slides on Enzymes 1) What are enzymes? 2) What do they do in your body? What is their basic function? 3) What are enzymes made up of? 4) What term describes the way an enzyme fits a specific substrate? 5) What temperature do bodily enzymes often work quickest at? 6) What happens to an enzyme if it gets too hot? 7) What approximate ph range would you want an enzyme in your stomach to work best at? 8) Name 3 places in your digestive system that enzymes are produced in.

11 The Digestive System What s the point of the digestive system? The whole point of digestion is to break down our food into small molecules which the body can then use to make carbohydrates, lipids and proteins. Here s how enzymes are involved:

12 Bloodstream Enzymes in digestion Enzymes can be produced by the body to help. When they come into contact and react with food they break it down into pieces which can then pass into the : Amylase (produced in the mouth, pancreas and small intestine) breaks (a carbohydrate) down into glucose: Protease (produced in the stomach, pancreas and small intestine) breaks down into amino acids: Lipase (produced in the pancreas and small intestine) breaks fats ( ) down into fatty acids and glycerol: Words blood, lipids, proteins, digestion, starch, smaller

13 Bile and The Liver Bile is a chemical produced in the liver and stored in the gall bladder. It has 2 functions: 1) It neutralises stomach acid and produces alkaline conditions for enzymes to work in 2) It emulsifies ( breaks down fats: The alkaline conditions and large surface area of the droplets means that fats are broken down by lipase much quicker. Fat globules Fat droplets

14 The Respiratory System

15 Diffusion in the lungs Oxygen diffuses in and carbon dioxide diffuses out of blood in the lungs: CO 2 Alveoli have three things that help them to do this job: a massive surface area, a moist lining that is only one cell thick and a very good blood supply.

16 The Circulatory system The circulatory system is responsible for pumping around the body. We need blood to be taken around the body because blood contains and. These are needed so that all the in our bodies can produce through. The main organs in the circulatory system are the, the lungs and the kidneys. Words energy, heart, blood, glucose, respiration, oxygen, cells

17 Double Circulation 1) Blood gets pumped from the right ventricle in the heart to the lungs and picks up oxygen. 2) The blood is then taken back to the heart 5) After the oxygen and glucose have been removed for respiration the blood is sent back to the heart and starts again 3) The left ventricle of the heart then pumps the blood to the intestine (where oxygen and glucose are removed)... 4) and to the rest of the body (where oxygen is also removed)

18 The Heart (in more detail) 1. Deoxygenated blood (i.e. blood without oxygen) enters through the vena cava into the right atrium 4. Oxygenated blood from the lungs enters through the pulmonary vein into the left atrium 2. It s then pumped through the tricuspid valve into the right ventricle 3. It s then pumped through a valve up to the lungs through the pulmonary artery 5. It s then pumped through a valve into the left ventricle 6. It s then pumped out of the aorta to the rest of the body

Heart rate and Pacemakers The heart beat is normally

19 Heart rate and Pacemakers The heart beat is normally controlled by a group of on the hand side of the heart called the pacemaker. These cells control the heart rate by producing small impulses that cause the heart to. If the pacemaker fails, an pacemaker can be fitted. Words artificial, right, cells, electrical, contract

20 Arteries, veins and capillaries Arteries carry high pressure blood away from the heart. They have smaller lumen and no valves. Capillaries have thin walls (one cell thick) to allow glucose and oxygen to pass through. Also used to connect arteries to veins. Lumen Veins carry low pressure blood back to the heart. They have thinner, less elastic walls and have valves to prevent backflow of blood.

21 The four parts of blood 1. RED BLOOD CELLS contain haemoglobin and carry around the body. They have no and a large surface area. 2. PLATELETS small bits of cells that lie around waiting for a cut to happen so that they can (for a scab). 3. WHITE BLOOD CELLS these help the body fight. These three are all carried around by the PLASMA (a straw-coloured liquid). Plasma transports CO 2 and as well as taking away waste products to the. Words clot, kidneys, oxygen, nucleus, glucose, infection

22 Heart disease In coronary heart disease layers of fatty material build up. What affect does this have on the heart? Drugs called statins can be used to reduce cholesterol levels and slow down the build up of fatty material.

23 Heart disease Arteries can narrow due to cholesterol and other factors. If this happens a stent may be needed:

24 Mending the Heart What are the pros and cons of using the following artificial products?

25 Who is the most healthy? Health Health is the state of physical and mental well being. How do these people s lifestyles promote health?

26 How Diseases can Interact Diseases can interact with each other when they affect the body. Here are some examples: Defects in the immune system mean that a person can catch an infectious disease more easily. Viruses in living cells can be a trigger for cancer. Severe physical ill health can lead to depression and other mental illnesses Immune reactions (after being caused by a pathogen) can cause allergies such as skin rashes

27 Interpreting Data about Health % obesity in the UK What does this graph tell you?

28 More examples of data What conclusions (for 3 marks) can you draw from these statistics? Q1) Q2) Source Public Health England Source Cancer Research UK

What can cause the following diseases or conditions? Match the disease to the risk factor.

29 Non-communicable diseases Non-communicable diseases are ones that can t be caught or transmitted. They can be caused by things like organ failure or poor diets. What can cause the following diseases or conditions? Match the disease to the risk factor. 1) Heart disease 2) Cancer 3) Diabetes 4) Liver failure 5) Lung cancer 6) Premature birth Too much alcohol The presence of carcinogens Poor diet and lack of exercise Obesity Smoking and alcohol Smoking

Cancer It is estimated that one in three people will develop cancer of some form during their lifetime. What is it? Benign tumours and malignant tumours can result from uncontrolled cell division.

30 Cancer It is estimated that one in three people will develop cancer of some form during their lifetime. What is it? Benign tumours and malignant tumours can result from uncontrolled cell division. Malignant tumours are cancer they invade neighbouring cells and spread to other parts of the body where they form secondary tumours. What causes cancer? The following are risk factors : 1) Genetic factors 2) Smoking 3) Obesity 4) UV exposure

31 2.3 Plant Tissues, Organs and Systems

Examples of Plant Tissue 1) Epidermal tissue, which covers the plant 2) Palisade mesophyll, where photosynthesis occurs 3) Spongy mesophyll, where gases move

32 Examples of Plant Tissue 1) Epidermal tissue, which covers the plant 2) Palisade mesophyll, where photosynthesis occurs 3) Spongy mesophyll, where gases move through air spaces 4) Xylem and phloem, which are used to transport substances around the plant 5) Meristem tissue found at the growing tips of shoots and roots

33 Cross section of a leaf Lots of chlorophyll Large surface area Transparent Thin structure Packed with chloroplasts Network of veins Lots of air spaces Guard cells and holes

34 Plant organs and transporting substances A group of CELLS makes up a TISSUE A group of TISSUES makes up an ORGAN, in this case, a leaf A group of ORGANS makes up a SYSTEM. In a plant, the roots, stem and leaves form a system that is used to transport substances around the plant.

Transpiration 1) Water evaporates through the stomata 2) Water passes back into the leaf through xylem vessels by osmosis 3) Water is then pulled upwards through the

35 Transpiration 1) Water evaporates through the stomata 2) Water passes back into the leaf through xylem vessels by osmosis 3) Water is then pulled upwards through the xylem tissue 4) This is replaced by water entering from the root tissue 5) Water enters root hair cells by osmosis to eventually replace the water lost through respiration

36 Transpiration Rate What factors would cause transpiration to happen the quickest? 1) Temperature what temperature do you think transpiration is quickest at? 2) Humidity is transpiration quicker when it is more or less humid? 3) Air flow how does this affect transpiration? 4) Light intensity how would this affect transpiration?

37 Xylem and Phloem Xylem are used by the plant to transport and soluble mineral from the roots to the stem and the leaves. Xylem are hollow strengthened by lignin. Phloem are tubes used by the plant to transport dissolved to the whole plant for and storage. The movement of food through phloem is called. Phloem is composed of tubes of elongated cells where cell sap can move from one phloem cell to the next through in the end walls. Words tubes, translocation, salts, water, sugars, respiration, pores

38 Root hair cells Plant roots are made of root hair cells which have two features that help them to take in water and nutrients ( active uptake ): Root hair cells Large surface area Thin cell membrane

39 Guard Cells and Stomata The roles of guard cells and stomata are to control gas exchange and water loss.

4.2.1 Principles of organisation Animal tissues, organs and organ systems The human digestive system

4.2.1 Principles of organisation Animal tissues, organs and organ systems The human digestive system GCSE Biology (8461). For exams 2018 onwards. Version 1.0 4.2 Organisation In this section we will learn about the human digestive system which provides the body with nutrients and the respiratory system