bio c3

• What happens in coronary heart disease?


  1. Layers of fatty material build up inside the coronary arteries, narrowing them.

  2. This reduces the flow of blood through the coronary arteries, resulting in a lack of oxygen for the heart muscle
• Statins


  Medicine which is widely used to reduce blood cholesterol, which slows down the rate of fatty deposit
• Problems with heart valves (2)


  1. May become faulty, preventing the valve from opening fully

  2. May develop a leak
• Consequences of faulty valves (3)


  1. Blood circulation is inefficient

  2. Resulting in tiredness, breathlessness or difficulty when exercising

  3. If untreated, eventual death
• In case of heart failure...

  ...a donor heart, or heart and lungs can be transplanted
• Epidemiology


  The study of factors affecting the health and illness of populations.
• Sampling


  When a predetermined number of specimens are taken from a larger population
• Human and financial cost of non-communicable diseases to individuals, local community, nation & globally

  1. Individual: impacts individual & family, financial cost if wage-earner becomes ill

  2. Local communities bear cost through taxes & taking care of individuals

  3. Costs nations money by treatment and loss of money as people cannot work

  4. Globally affected as NCDs affect more people than CDs - economically esp when working age population affected
• Examples of risk factors for NCDS


  1. Diet

  2. Fitness levels

  3. Obesity

  4. Smoking

  5. Drinking alcohol

  6. Exposure to carcinogens in environment e.g. ionising radiation
• Risk factors can be...

  ...1. aspects of a persons lifestyle

  2. substances in the person's body or environment
• What are 3 risk factors for cardiovascular disease?


  Diet, smoking and exercise
• What are the links between lifestyle choices and cardiovascular disease?

  1. Frequent exercise brings down cholesterol levels so plauqes do not form on your arteries

  2. Diet affects your cholesterol levels

  3. Scientists have collected evidence that people who exercise regularly are less likely to develop cardiovascular disease
• Explain the effects of tar (4)

  1. Black, sticky substance which accumulates in the lungs

  2. Paralyses cilia, making colds and bronchitis more likely

  3. Can lead to breakdown of alveoli causing COPD and breathlessness

  4. Contains carcinogens which lead to cancer
• Explain the effects of nicotine (2)

  1. Addictive drug that acts as a stimulant on brain & nervous system

  2. Increases heart rate and narrows blood vessels, causing high blood pressure & other health problems
• Explain the effects of carbon monoxide (1)

  1. Poisonous gas which combines with haemoglobin in red blood cells, reducing the oxygen they can carry
• Carcinogens in cigarette tar


  Cause genetic mutations and lead to cancer
• Type 2 diabetes risk factors (2)

  1. Genetics

  2. Obesity
• Explain the effects of alcohol on the liver (2)

  1. Cirrhosis - active liver tissue is replaced with scar tissue that cannot carry out vital functions

  2. Increased risk of cancer - alcohol is a carcinogen
• Explain the effects of alcohol on the brain (3)

  1. Initially reduces inhibitions

  2. Damages brain, making it soft so some structures lost

  3. Can lead to memory loss and difficulty processing new information
• Risk factors of cancer

  1. Ionising radiation - overexposure to sun, UV light causing melanomas

  2. Carcinogens (e.g. in smoking) cause mutations to the genetic material

  3. Genetic risk factors e.g. in breast cancer

  4. Viral infections e.g. HPV leading to cervical cancer
• Benign tumours


  Growths of abnormal cells which are contained in one area, usually within a membrane, that do not invade other parts of the body
• Describe the functions of plant tissues (5)

  1. Epidermal tissues - cover surface & protect them; cells often secrete waxy substance that waterproofs leaf

  2. Palisade mesophyll - chloroplasts for photosynthesis

  3. Spongy mesophyll - chloroplasts for photosynthesis, air spaces for gas exchange

  4. Xylem and phloem - transport tissue

  5. Meristem tissue - rapidly dividing cells at roots and shoots that grow and differentiate into necessary cell types
• What cells make up the leaf? (5)


  1. Waxy cuticle

  1. Upper epidermal layer

  2. Mesophyll layer - palisade & spongy

  3. Lower epidermal layer

  4. Stomata - allow gases to move in and out of leaf

  5. Guard cells - control opening and closing of stomata

  6. Waxy cuticle

  
• Where is meristem tissue found?


  At the growing tips of shoots and roots
• The roots, stem and leaves form...


  ...a plant organ system for transport of substances around the plant
• What is the role of the stomata and guard cells?

  to control gas exchange and water loss
• Xylem tissue - function and adaptations

  1. Transports water and mineral ions from the roots to the stem and leaves

  2. Hollow tubes strengthened by lignin which waterproofs vessels

  3. Adapted for the transport of water in the transpiration stream
• Phloem tissue - function and adaptation (4)


  1. Transports dissolved sugars from leaves to the rest of the plant

  2. For immediate use or storage

  3. The movement of food molecules through phloem tissue is called translocation

  4. Tubes of elongated cells; cell sap can move from one phloem cell to next through pores in the end walls
• What are stomata?

  Small openings in the leaf which can be opened to allow gases to enter the leaf. The size and opening and closing of the stomata is controlled by guard cells.
• How does temperature affect transpiration?


  1. Molecule move faster as temperature increases, more rapid evaporation

  (2. Rate of photosynthesis increases, more stomata open)
• How are root hair cells adapted for osmosis and active transport?

  1. High surface area for efficient uptake of water by osmosis

  2. Mitochondria transfer energy needed for active transport of mineral ions
• How does humidity affect transpiration?

  Water vapour diffuses more rapidly into dry air than humid air because the concentration gradient is steeper
• How does air movement (wind) affect transpiration?

  1. Windy conditions increase the rate of evaporation

  2. They also maintain a steep concentration gradient from the inside to the outside of the leaf by removing water vapour as it diffuses out
• How are red blood cells adapted for efficiency?

  1. Biconcave shape increase SA:vol ratio

  2. Filled with haemoglobin which binds to oxygen

  3. No nucleus so more space for haemoglobin