OCR Gateway Biology B2

Frage	Antworten
How is Blood transported to all parts of the body at the correct pressure?	Each time the heart beats, its muscles contract pushing blood out into the arteries at the correct pressure
What is Systolic and Diastolic blood pressure?	Systolic Blood Pressure is the pressure in the arteries when the heart contracts Normal = 120 mmHg ( millimeters of mercury ) Diastolic Blood Pressure is the pressure in the arteries when the heart relaxed Normal = 80 mmHg
Name 2 things that can lower resting blood pressure	Regular exercise & Eating a balanced healthy diet
Explain how smoking causes high blood pressure	Tobacco smoke contains Nicotine and Carbon Monoxide Carbon monoxide combines with Haemoglobin in Red blood cells and prevents them carrying as much Oxygen, the heart rate increases to compensate putting a strain. Nicotine increases heart rate
Explain how eating lots of saturated fat may increase blood pressure	Our livers use saturated fat to make cholesterol, the cholesterol may be deposited in artery walls leading to a blood clot ( thrombosis ) which can cause heart attack
State 3 health risks from high blood pressure	High blood pressure (above 140/90mmHg) can result in a : - Have a heart attack - Have a stroke - Kidney damage
Why do you need : a- Vitamins b- Minerals c- Fibre d-Water	a- To prevent scurvy b- To make haemoglobin c-To prevent constipation d- To prevent dehydration
What are the health risks of being obese?	Obese people are more likely to suffer from: - Heart disease - Diabetes - Arthritis - Breast Cancer
What is the BMI of someone who is 1.6m tall and weighs 60 kg?	60/1.7^2 = 20.8
List 5 ways to reduce risk of cancer	- Sunbathe a little - Avoid eating much fat and don't become overweight - Avoid eating red meat and processed food - Regular Exercise - Avoid Alcohol / smoking
State the 4 types of Pathogen and what diseases each one causes	Fungi - Causes athlete's foot Bacteria - Causes Cholera Viruses - Flu Protozoa - Malaria
What are antibiotics?	Chemicals produced by some fungi and bacteria to kill / prevent growth of other fungi and bacteria e.g. Penicillin
Explain why antibiotics have to be used carefully?	Doctors should not prescribe them if not needed, should the patient need it, they must finish the whole course. If antibiotics are not used properly, resistant strains of bacteria develop e.g. MRSA
How do Pathogens enter the body?	Pathogens can enter the body through : - Cuts - Contaminated food /drink - Sexual Intercourse ( STD ) - Air ( Air born diseases )
What are antibodies?	Special proteins in the body that can destroy a particular pathogen/virus
What are Antigens?	Toxins that Pathogens produce that cause harm to an organism
Name the barriers that the body has to stop pathogens entering it ( 5 )	- Skin - Stomach Acid - Tears - Blood clotting from cuts - Mucus in airways
What is Passive and Active Immunity?	Active Immunity is where the body is actively producing antibodies to fight infection. Passive Immunity is where Antibodies are given from one to another. Passive Immunity works almost instantly but doesn't last as long as Active Immunisation
Explain what Accommodation is	Accommodation is where : - For near objects, the ciliary muscle is contracted and the suspensory ligaments are relaxed so the lens become round and flat. - For distant objects the ciliary muscle relaxes and the suspensory ligaments become contracted
Explain the differences between Long sightedness & Short sightedness	Short Sightedness is where the image/light rays are focused before the retina ( eyeball too long ), this can be corrected by diverging (concave) lenses. Long Sightedness is where the image/light rays don't meet at the retina ( eyeball too short ), this can be corrected by converging (convex) lenses.
Name the 2 parts of the nervous system	Central Nervous System & Peripheral Nervous System
What are Receptor cells?	Special cells adapted to detect stimuli, information from the receptors travel along neurones to the brain
What are the 2 types of response the body has?	Voluntary Responses- Responses consciously controlled by the brain Reflex Actions- Response controlled by CNS , they are faster ( don't rely on brain ) automatic and protective
Explain the pathway of nerve impulses in reflex actions	Stimulus---Receptor---Sensory Neurone---Relay Neurone---Motor Neurone---Effector---Response
What are some Short-term & Long-term effects of alcohol?	Short Term : - Blurred Vision - Impaired speech - Impaired judgement - Drowsiness - Violent Behaviour Long Term : -Cirrhosis of liver - Brain damage -> Loss of memory & depression - Fatty Liver - Risk of diabetes and heart disease - Liver, Mouth, Throat and Oesophagus cancer
What is Negative Feedback?	Negative Feedback is the mechanism that keeps things at a steady level
What is Homeostasis?	Maintaining a constant internal enviroment Pathway: Un-normal levels---sensory organs---control centre-effector
What are Hormones?	Hormones are chemicals. They.. - Are secreted from glands in the bloodstreams - Travel in the blood to target organs - Regulate the functions of many organs and cells - Coordinate many processes in the body
Define: 1- Tropism 2- Positive Tropism 3- Negative Tropism 4- Phototropism 5- Geotropism	1- Growth in response to a stimulus 2- Growth Towards the stimulus 3- Growth Away from the stimulus 4- Growth in response to the direction of light 5- Growth in response to the direction of gravity
What is an Allele?	Alternative forms of a gene that arise by mutation and are found at the same place on a chromosome.
What are chromosomes?	A thread-like structure of nucleic acids and protein found in the nucleus of most living cells, carrying genetic information in the form of genes.
What are Gametes?	Special sex cells which only 23 chromosomes instead of 23 matched pairs, Female gametes are eggs Male gametes are sperms

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