B1 - Understanding Organisms Flash Cards

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Biology: Understanding Organisms B1 Flash Cards	By Aneeqa Ahmed
Blood Pressure	This is measured in millimetres of mercury, and is written as mmHg. It has two measurements: systolic pressure (maximum pressure the heart produces) and diastolic pressure (blood pressure between heart beats)
Blood Pressure (Increasing and Decreasing)	It can be increased by stress, high alcohol intake, smoking and being overweight. It can be decreased by regular exercise and eating a balanced diet.
High Blood Pressure	This can cause blood vessels to burst, it can cause damage to the brain, which is often called a stroke. It can also damage the kidneys.
Low Blood Pressure	This can lead to dizziness and fainting as the blood supply to the brain is reduced and poor circulation to other areas such as the fingers and toes.
Fitness and Health	Fitness is the ability to do physical activity. Health is being free from diseases such as those caused by bacteria and viruses.
Level of fitness being measured	It can usually be measured by cardiovascular efficiency. It can also be measured for different activities such as Strength (weights lifted), Flexibility (Joint movement) , Stamina (Sustained Exercise), Agility (change of direction) and Speed (Sprint Race).
Smoking (Increasing Blood Pressure)	From Carbon Monoxide in cigarette smoke causes blood to carry less oxygen, this means the heart rate increases so that tissues receive enough oxygen. Nicotine in cigarette smoke directly increases the heart rate.
Smoking (Effects of Carbon Monoxide)	This decreases the oxygen carrying capacity of blood. It combines with Haemoglobin, preventing it from combining with oxygen, so less oxygen is carried.
Heart Disease	This is caused by a restricted blood flow to the heart muscle. The risk of getting this is increased by: A high level of saturated fat in the diet which leads unto build up of cholesterol (plaque) in the arteries.
Heart Disease 2	Narrowing of the arteries caused by plaques in the coronary arteries can reduce flood flow to the heart muscle. The plaques also make blood clots or thrombosis more likely to happen, which also blocks the artery.
Balanced Diet (Carbohydrates)	They are made up of simple sugars such as glucose.
Balanced Diets (Proteins and Fats)	Proteins - These are made up of amino acids. Fats - These are made up of fatty acids and glycerol.
Balanced Diets (Too much Fat or Carbohydrates)	They are stored in the body: Carbs are stored in the liver as glycogen or are converted into fats. Fats are stored under the skin and around organs as adipose tissue. Proteins can't be stored in the body.
Protein Intake	Proteins are needed for growth and so it is important to eat the correct amounts. This is called the estimated average daily requirements (EAR) and can be calculated using the formula.
Formula for EAR	EAR in g = 0.6 x body mass in kg
The EAR	This is only an estimated figure based on an average person. The EAR for protein might be affected by factors such as body mass, age, pregnancy or breast feeding (lactation). Proteins cannot be stored in the body, some amino acids are converted by the body into other amino acids
First Class Proteins	These are proteins from meat and fish, they contain all the essential amino acids that cannot be made by the human body.
Second-Class Protein	These are known as the plant proteins, and they contain all the essential amino acids that cannot be made by the human body.
BMI (Body Mass Index)	This is used to work out if a person is overweight or underweight BMI = Mass in kg/(height in m)²
Malaria	Malaria is caused by a protozoan called plasmodium, which feeds on human red blood cells.
Plasmodium	Plasmodium is carried by mosquitoes, which are vectors (not affected by disease) and transmitted to humans by bites. Plasmodium is a parasite and humans are its host. It is an organism that feeds on another living organism, causing it harm.
Mosquitos Life Cycles	Knowledge of this has helped to stop the spread of malaria (by draining stagnant water, putting oil on the water surface and spraying insecticide). This knowledge has also helped to develop new treatments for malaria.
Cancers (Reducing Risks of Cancer)	Changes in lifestyle and diet can reduce the risk of some cancers, for example: - Not smoking reduces the risk of lung cancer. - Using sunscreen reduces the risk of skin cancer.
Benign Tumour Cells + Cancer.	Benign tumour cells such as warts, divide slowly and are harmless. Cancers are malignant tumours: the cells display uncontrolled growth and may spread. Interpreting data on cancer and survival/mortality rates should be considered.
The fight against illness 1	Pathogens (disease - causing organisms) produce the symptoms of an infectious disease by damaging the body's cells or producing poisonous waste products called toxins.
The fight against illness 2	The body protects itself by producing antibodies, which lock onto antigens on the surface of pathogens such as bacterium. This kills the pathogen.
The fight against illness 3	- Human white blood cells produce antibodies, resulting in active immunity. This can be a slow process but had long lasting effect. - Vaccinations using antibodies from another human result in passive immunity, which has quick but short-term effect.
Pathogens.	Each pathogen has its own antigens, so a specific antibody is needed for each pathogen.
Process of Immunisation (Also known as Vaccination)	1. It starts with injecting harmless pathogen carrying antigens. 2. The antigens trigger a response by white blood cells, producing the correct antibodies. 3. Memory calls (a type of T-lymphocyte) remain in the body, providing long lasting immunity to that disease.
Immunisation	Immunisation carries a small risk to the individual, but it avoids the potentially lethal effects of the pathogen, as well as decreasing the risk of spreading the disease.
Treatments and Trials: (Placebo)	A placebo is a harmless pill. Placebos are used as a comparison in drug testing so the effect of a new drug can be assessed.
Treatments and Trials: (Blind Trials)	A Blind Trial is when the patient doesn't know whether they are receiving a new drug or a placebo. In a double blind trial, neither the patient nor the doctor know which treatment is being used. These types of trial avoid a 'feel-good factor' and a biased opinion.
Treatments and Trials: (Excessive use of antibiotics)	Excessive use of antibiotics has resulted in resistant forms of bacteria being more common than non-resistant forms, for example resistant MRSA has thrived, causing serious illnesses.
Antibiotics	Antibiotics (against bacteria and fungi) and antiviral drugs (against viruses) are specific in their action. An antibiotic destroys a pathogen; and antiviral drug slows down the pathogen's development.
New Treatments	New treatments such as vaccinations, are tested using animals, human tissue and computer models before human trials. Some people object to causing suffering in animals in such tests.
How do eyes work	Main parts of The eye have special functions. Light rays are refracted (bent) by the cornea and lens. The retina contains light receptors. some are sensitive to other colours.
Binocular Vision	Binocular vision helps to judge distances by comparing the images from each eye; the more different they are, the nearer the object.
Accommodation	This is when the eye can focus light from a distance or near objects by altering the shape of the lens.
Focusing on distant and near objects:	Distant Objects: The ciliary muscles relax, the suspensory ligaments tighten so the lens has a less rounded shape. Near Objects: The ciliary muscles contract and the suspensory ligaments slacken, so the lens regains a more rounded shape due to it elasticity.
Faults in Vision: (Red - Green colour blindness)	Red - green colour blindness caused by a lack of specialised cells in the retina.
Faults in Vision: (Long and Short vision 1)	Long and short vision are caused by the eyeball or lens being the wrong shape.
Faults in Vision: (Long Sighted)	In Long Sight the eyeball is too short or the lens is too thin, so the image is focused behind the retina.
Faults in Vision: (Short Sighted)	In short sight the eyeball is too long or the lens is too rounded so the lens refracts the light too much, so the image would be focussed in front of the retina.
Faults in Vision: (Correcting Long/Short sight)	Corneal surgery or a lens in glasses or contact lenses correct this long or short sight. A convex lens is used to correct long sight and a concave lens to correct short sight.
Nerve Cells	Nerve cells are called neurones, nerves impulses pass along the axon.
Pathway for a spinal reflex:	Receptor --> Sensory Neurone --> Relay Neurone --> Motor Neurone --> Effector.
Links in a refex arc: (This is what happens in a reflex action)	Stimulus --> Receptor --> Sensory Neurone --> Central Nervous System --> Motor Neurone --> Effector --> Response.
Nerve Cells 1	Neurones are adapted by being long, having branched endings (dendrites) to pick up impulses and having an insulator sheath.
Nerve Cells 2	Synapse - The gap between neurones. The arrival of an impulse triggers the release of a transmitter substance, which diffuses across the synapse. The transmitter substance binds with the receptor molecules in the membrane of the next neurone causing impulse to continue.
Types of Drugs: (Class A,B and C)	Drugs have a legal classification. Class A drugs are the most dangerous and have the heaviest penalties. Class C are the least dangerous and have lightest penalties.
Different types of drugs:	Depressants: alcohol + solvents Painkillers: Aspirin and Paracetamol Stimulants: Nicotine, MDMA + Caffeine Performance Enhancers: Anabolic Steroids Hallucinogens: LSD
Drugs and The Nervous System	Depressants block the transmission of nerve impulses across synapses by binding with the receptor molecules in the membrane of the receiving neurone. Stimulants cause more neurotransmitter substances to cross synapses.
Effects of Smoking (Cilia)	Cigarette smoke contains many chemicals that stop cilia moving. Cilia (tiny hairs) are found in the epithelial lining of the trachea, bronchi + bronchioles.
Effects of Smoking ('Smoker's Cough')	This is a result of: - Dust and particles in cigarette smoke collecting and irritating the epithelial lining. - Mucus not being moved by the cilia.
Effects of Alcohol	Alcohol content of alcoholic drinks is measured in units of alcohol. - Drinking Alcohol increase reaction times and the risk of accidents. - The liver is damages when it breaks down toxic chemicals such as alcohol. (Known as Cirrhosis of the liver)
Homeostasis	Homeostasis is keeping a constant internal environment. Homeostasis involves balancing bodily inputs and outputs.
Homeostasis 2	Automatic control systems keep the levels of temperature, water and carbon dioxide steady. This makes sure all cells can work at their optimum level. Negative feedback controls are used in this. They act to cancel out change such as a decreasing temperature level.
Temperature Control	The body temperature of 37 °C is linked to the optimum temperature for many enzymes.
Temperature Control (A High Temperature)	A high temperature can cause: - Heat Stroke (Skin becomes cold and clammy and pulse is rapid and weak) - Dehydration (Loss of too much water) (Both can be fatal if not treated)
Temperature Control (Avoiding overheating)	To avoid overheating, sweating increases heat transfer from the body to the environment. The evaporation of sweat requires body heat to change the liquid sweat into water vapour.
Temperature Control (Low Temperatures)	A very low temperature can cause hypothermia (slow pulse rate, violent shivering) which can also be fatal if not treated.
Blood Temperature	Blood Temperature is monitored by the hypothalamus gland in the brain. Reaction to temperature extremes are controlled by the nervous and hormonal systems, which trigger vasoconstriction or vasodilation.
Vasoconstriction	Vasoconstriction is the constriction of (narrowing) of small blood vessels in the skin. This causes less blood flow and less heat transfer. (Size is altered not the movement)
Vasodilation	Vasodilation is the dilation (widening) of small blood vessels in the skin. This causes more blood flow near the skin surface resulting in more heat transfer. (Size is altered not the movement)
Blood Sugar Levels	A hormone called insulin controls these blood sugar levels. Hormone action is slower than nervous reactions as the hormones travel in the blood.
Blood Sugar Levels 2	Insulin converts excess glucose in the blood into glycogen, which is stored in the liver. This regulates blood sugar levels. -Insulin dosage in Type 1 diabetes needs to vary according to persons diet and activity. Strenuous exercise needs more glucose to be present in the blood, need a lower dose.
Type 1 and Type 2 Diabetes	Type 1 - This is caused by the pancreas not producing any insulin, treated by doses of insulin. Type 2 - Caused by the body either producing too little insulin to body not reacting to it, controlled by diet.
Plant Responses 1	Phototropism - This is the plant's growth response to light. Geotropism - This is a plant's growth response to gravity.
Plant Responses 2 (Shoots)	Different parts respond in different ways: - Shoots are positively phototropic (grow towards light) and negatively geotropic (grow away from the pull of gravity)
Plant Responses (Roots)	- Roots are negatively phototropic when (they grow away from light). - They are positively geotropic when (they grow with the pull of gravity)
Plant Hormones (auxins)	Auxins are a group of plant hormones. They move through the plant in solution. They are involved in both phototropism and geotropism. Auxins are made in the root and shoot tip.
Plant Hormones (auxins) 2	Different amounts of auxins are found in different parts of the shoot when tip is exposed to light. More auxin is found in shady parts. Higher amount of auxin will increase amount of cells. Therefore increase in cell length on shady side causes curvature of the shoot towards the light.
Commercial uses of plant hormones	- As selective weedkillers, kill specific weeds and increase crop yield. - As rooting powder to increase root growth of cuttings. - To delay/accelerate fruit ripening to meet market demands. - To control dormancy in seeds.
Inherited Characteristics 1	Some human characteristics, such as facial features can be inherited. They can be both dominant or recessive. Alleles are different versions of the same gene.
Inherited Characteristics 2	Dominant and recessive characteristics depend on the dominant and recessive alleles. A gene can have two different alleles, 1 Dominant + 1 Recessive. - Dominant Alleles are expressed when present but recessive alleles are expressed only in absence of dominant allele.
Chromosomes 1	Most body cells have the same number of chromosomes. The number depends on the species of organism, human cells have 23 pairs. A sperm will either carry an X or Y chromosome. All eggs will carry X chromosomes. There is random chance of which sperm fertilises the egg.
Chromosomes 2	There is an equal chance of the offspring being male or female. Sex chromosomes determine the sex in mammals. Females have identical sex chromosomes called XX, Males have different chromosomes called XY.
Genetic Variation	These are caused by: - Mutations (random changes in genes or chromosomes) - Rearrangement of genes during the formation of gametes. - Fertilisation, results in zygote with alleles from the father and mother.
A Monohybrid Cross	Involves 1 pair of characteristics controlled by a single gene, 1 allele being dominant and 1 recessive.
Homozygous + Heterozygous	Homozygous means having identical alleles. Heterozygous means having different alleles.
Genotype and Phenotype	A person's genotype is their genetic make-up. Their Phenotype is which alleles are expressed.
Inherited Diseases	They are caused by faulty genes. They are caused by faulty alleles, most of which are recessive. It is possible to predict the probability of inheriting such disorders by interpreting genetic diagrams.
Inherited Disorders (Personal and Ethical issues)	- In deciding to have a genetic test. (Positive outcome could alter lifestyle, career and insurance) - By knowing the risks of passing an inherited disorder (Whether to marry/Have a family)
Monocular Vision	This is having a wider field of view but poorer distance judgement than binocular vision.

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