Biology B1

Question	Answer
Biology B1 Flashcards	.
Being Fit and Being Healthy	Being FIT is a measure of how well you can perform and being HEALTHY is being free of any infections or diseases. Fitness profiles measure strength, speed, agility and flexibility, together with stamina. Stamina is a good indication of cardiovascular efficiency. It can be tested by measuring oxygen uptake during exercise, and blood pressure.
Blood Pressure (mmHg)	Blood is pumped around the body by contractions of the heart. These contractions increase the pressure of the blood. This blood is flows through arteries and thousands of capillaries which take the blood to every cell in the body. The blood then flows back to the heart through veins, the pressure lowers as blood flows through the system. The pressure is at it's highest when the heart contracts (systolic pressure) The pressure is at it's lowest when the heart relaxes (diastolic pressure). Smoking Obesity Alcohol Stress These can all increase blood pressure.
High and Low Blood Pressure	High blood pressure can cause blood vessels to burst which leads to strokes, brain damage and kidney damage. Eating a balanced diet, doing exercise and certain drugs can decrease blood pressure. Low blood pressure can cause poor circulation and tissues don't get enough food and oxygen that they need. If your brain doesn't get enough food and oxygen you will become dizzy and faint.
Smoking on Blood Pressure.	Carbon Monoxide combines with hemoglobin in red blood cells, which reduces the amount of oxygen they can carry. To make up for this heart rate increases so that tissues get enough oxygen. This increases the amount of hear contractions which increases blood pressure. Nicotine also increases the heart rate.
Heart Attack and Cholesterol	Saturated fats can cause cholesterol build up Cholesterol is a fatty substance which is needed for making things like cell membranes, but too much cholesterol will cause a build up in arteries. This form plaque in the artery wall, which narrow the arteries. This plaque will restrict the blood flow which can lead to a heart attack. The blood is supplied to the heart by coronary arteries and if these become too narrowed blood flow will be restricted and the heart receives less oxygen. a thrombosis (blood clot) will also restrict blood flow. A thrombosis will occur in an already narrowed coronary artery and this will cause blood flow to be blocked completely this cuts off oxygen to an area of the heart which causes a heart attack
Balanced Diet (carbs, fats, proteins, vitamins and minerals and water)	CARBOHYDRATES are made up of simple sugars and provide energy. They are stored in the liver as glycogen or converted to fats. FATS are made up of fatty acids and glycerol, these provide energy, acting as an energy store and providing insulation. They can be stored under the skin and around organs as adipose tissue. PROTEINS are needed for growth and repair of tissue and act as energy in emergencies. They are made up of amino acids and some cannot made by the body so we need to get essential amino acids from our diet. Animal proteins (1st class proteins) contain all essential amino acids. Plant proteins (2nd class proteins) do not contain all essential amino acids. Energy and nutrient needs vary between people. It depends on AGE, children and teens need more protein for growth but older people need more calcium to protect against degenerative bone diseases. It also depends on GENDER, females need more iron to replace the iron lost when menstruating. It also depends on PHYSICAL ACTIVITY, active people need more protein for muscle development and carbs for energy.
EAR	In developing countries a lot of people have a condition called kwashiorkor which is when you don't have enough protein. The main reasons for this is overpopulation (the demand is protein rich foods is greater than the product given) or there is not enough money to invest in agriculture. EAR (g) = 0.8 x body mass (Kg) EAR is an estimate of the protein an average person needs. EAR varies with age and also changes before and after pregnancy. Eating disorders can also effect diet by under nutrition.
BMI	BMI is a guide used to help decide whether someone is underweight, normal, overweight or obese. It is calculate by their height and weight. BMI isn't always reliable . Athletes have a lot of muscle, which weighs more than fat therefore their BMI increases, but they're no overweight. An alternative to measuring BMI is measuring % body fat.
Pathogens	Pathogens are microorganisms that cause disease. There are four types: - Fungi -Bacteria -Viruses -Protozoa The symptoms of an infectious disease are cause by cell damage and toxins produced by the pathogens. Once pathogen enter your system they reproduce rapidly unless they're destroyed. White blood cells travel around in your blood. White blood cells consume and engulf foreign cells and digest them. They then produce antitoxins which counter the effect of any toxins produced by the pathogens. Each pathogen has unique antigens on the surface of it's cell so when white blood cells come across a foreign antigen they produce proteins called antibodies, these are produced quickly and flow through the body looking to kill similar bacteria/viruses. Antibodies produced are specific to that pathogen and lock onto the antigen and kill new invading cells.
Malaria	Malaria is caused by a protozoan and is carried by mosquitoes. The protozoan is a parasite. The mosquitoes are vectors and carry the disease without getting it themselves. They pick up this malarial parasite when they feed on an infected animal and every time that same vector feeds it infects them by inserting the parasite into their blood vessels. We can target the mosquitoes and we do this by draining or spraying insecticide on the areas where they lay their eggs. Also fish can be introduced into the water and will eat their larvae. People can also be protected from these by using mosquito nets.
Natural Immunity	Some white blood cells stay in the blood after the pathogen has been fought off. These are memory cells, if the person is infected with the pathogen these cells will remember it and immediately make antibodies - Natural immunity.
Active and Passive Immunity	When your body is infected by a new pathogen it can take a while to produce the antibodies to deal with it. Therefore you get injected with a dead/inactive pathogen which carry antigens so trigger your immune system response sending white blood cells. Some of these white blood cells will become memory cells so if live pathogens of the same type come back the antibodies will be produced immediately. Active immunity is permanent and works by stimulating your immune system with the harmless inactive pathogen. It includes becoming naturally immune and artificially immune. Passive immunity is where you use antibodies made by another organism and temporary.
Immunization Pros and Cons & Antibiotics	Immunization stops you getting ill and if more people are immune the disease won't spread as easily. However, there can be short-term side effects and you cannot have a vaccination if you're already ill. Antibiotics kill bacteria but not viruses. Antivirals can be used to treat viral infections, these stop viruses from reproducing. Some bacteria are naturally resistant to antibiotics an misuse of antibiotics has increased the rate of development of resistant strain.
Cancer Tumors	Cancer is cause by body cells dividing out of control. BENIGN - the tumor grows until there is no more room and the cells stay where they are, this isn't usually dangerous. MALIGNANT - the tumor grows and can spread to other site in the body, these are dangerous.
Development of A Drug	New drugs need to be thoroughly tested before used to make sure they're safe and that they work. 1. Computer models - these stimulate a humans response to a drug. This identifies promising drugs but isn't as accurate as actually testing on a live animal. 2. Human tissue - they test on human tissues, however drugs that effect whole/multiple body systems mus be done on a whole animal. 3. Develop drug and test on animals.
Drugs	Drugs are substances which alter the way a body works. Many drugs are dangerous if misused. Tolerance develops with a drug - the body gets used to having t so needs a higher dosage to have the same effect.
Different Drugs	Image: Capture_8.PNG (image/PNG)
Class Drugs	Image: Capture_9.PNG (image/PNG)
Alcohol	Alcohol mainly reduces the activity of the nervous system and is a depressant. It makes people feel less inhibited but is poisonous and when broken down by enzymes in the liver, it makes toxic products which causes death of liver cells forming scar tissue that stops blood reaching the liver. This is called cirrhosis. Being drunk leads to dehydration, poor judgment, poor balance, poor co-ordination, blurred vision, slurred speech and sleepiness.
Smoking	Nicotine in cigarettes make smoking addictive. Carbon monoxide is produced also which leads to a heart attack and deprive the foetus of oxygen leading to a baby with a low birth weight. Tar from smoke collects in the lungs and carcinogens in the tar make mutations in the DNA more likely. If this happens cell division can go out of control and malignant tumors can form. Smoking damages the cilia in on the the epithelial tissue lining the tubes in the lungs (trachea, bronchi and bronchioles) which encourages mucus to be produced but it cannot be cleared because the cilia are damaged so it sticks to the air passages causing smokers cough and emphysema (lungs losing their elasticity)
The Eye	Cornea bends light into the eye Iris control how light enters the pupil Lens refracts light focusing onto the retina The retina is light sensitive and covered in receptors called rods and cones which detect light. Rods are more sensitive in dim light but cannot sense colour. Cones are sensitive to different colours but are not as good in dim light. Optic Nerve carries impulses from the receptors to the brain. Image: Capture_10.PNG (image/PNG)
Accommodation	Image: Capture_11.PNG (image/PNG)
Short and Long Sighted People	Long--sited people are unable to focus on near objects. 1. This occurs when the lens in the wrong shape and doesn't bend the light enough. 2. The images of near objects are brought into focus behind the retina 3. You can use glasses with a convex lenses to correct this. Short-sited people are unable to focus on distant objects. 1. This occurs when the lens is the wrong shape and bends the light too much. 2. The images on distant objects are brought into focus in front of the retina. 3. You can use glasses with a concave lens to correct it.
Binocular Vision	Binocular vision is when two eyes work together and your brain compares the images seen by each eye. The more similarities between the images, the further away the object is. This allows us to judge distances but gives us a narrow field of vision.
CNS	Your Central Nervous System consists of your brain and spinal cord.
Reflex Arc	The nervous system uses electrical impulses to allow very quick responses. Reflex actions are automatic so they're even quicker. The conscious brain isn't involved in a reflex arc. The sensory neuron connects to a relay neuron in the spinal cord which links directly to the motor neuron so no time is wasted thinking about the right response. Reflex actions have a protective roles.
Nerves and Electrical Impulses	The electrical impulse is passed along the axon of the cell. Neurons have branched endings (dendrites) so they can connect with other neurons. They have a sheath along the axon which as an electrical insulator and speed sup the impulse. The nerves' long shape speeds up the impulse (connecting with another neuron slows impulses down so one long neuron is quicker than many short ones joined together. Image: Capture_13.PNG (image/PNG)
Synapses	The connection between two neurons is called a synapse, it is a tiny gap. The electrical impulse triggers the release of transmitter chemicals which diffuse across the gap. These chemicals bind with receptor molecules in the membrane of the next neurone which sets of a new electrical impulse. Stimulant drugs increase the amount of transmittor chemical at some synapses , which increases the frequency of the electrical impulse at neuron 2. Depressants bind with the receptor molecules on the membrane of neuron 2 which blocks the electrical impulse which decreases brain activity. Image: Capture_14.PNG (image/PNG)
Homeostasis and Negative Feedback	Homeostasis is maintaining a constant internal environment. Conditions in your body need to be kept steady so cells can function properly. This involves balancing inputs with outputs, for example: -CO2 -Water content Body Temperature Negative Feedback works automatically to keep the above steady. Changes in the environment trigger a response that counteracts the changes. This means that the internal environment tends to stay to stay at the norm which cells work best. However, this only works with certain limits, if the environment changes too much your body may not be able to counteract it.
Body Temperature	All enzymes have an optimum temperature they work best at and for humans this is 37 degrees. In your brain there is a thermoregulatory centre in which acts as a personal thermostat. It contains receptors that are blood temperature in the brain and receives impulses from the skin that provide information about skin temperature. Your brain can then respond using the nervous system, hormonal systems to initiate temperature control mechanisms.
Too Hot & Too Cold	HOT: Your hairs will lie flat Sweat is produced so it will use heat from your skin to evaporate and transfer the heat to the environment. Blood vessels close to the skin's surface widen which allows more blood flow near the surface, so it can radiate more heat into the surroundings. This is vasodilation. COLD: Hairs stand up to trap an insulating layer of air to keep you warm. Shivering generates heat in the muscles Blood vessels near the surface constrict so that less heat can be radiated to the surroundings. this is constructionist.
Glucose & Insulin	Eating carbs puts glucose into the blood from the gut. Glucose is removed from the blood by respiration and vigorous exercise. The levels of glucose must be kept steady so these changes are monitored by the pancreas using insulin. Insulin is a hormone and hormones travel in the blood so it can take quite a while for them to get where they're needed. Electrical impulses travel much faster. This means it takes longer to respond to a hormone than a nervous impulse
Glycogen	Glycogen can be stored in the liver until the blood sugar level is low again Image: Capture_15.PNG (image/PNG)
Diabetes	Diabetes is a condition in which your body cannot control it's blood sugar levels. TYPE 1 - The pancreas produces little r no insulin which makes their glucose levels rise enough to kill them. This often involves injecting insulin into their body at mealtimes which ensures that the glucose is quickly removed from the blood. The amount of insulin depends on diet and how active they are. TYPE 2 - The person becomes resistant to insulin because their body cells do not respond properly to this hormone. This causes blood sugar levels to rise to high levels. This involves controlling diet and limiting intake of foods rich in simple carbs
Auxin	Auxins are plant hormones which control growth at the tips of shoots and roots. They move through the plant in solution. Auxin is produced in the tips and diffuses backwards to stimulate the cell elongation process which occurs in the cells just behind the tips. It promotes growth in the shoot but inhibits growth in the roots. They are involved in growth responses to light (phototropism) and gravity (geotropism).
Phototropism & Geotropism	PLANT SHOOTS grow towards light so are POSITIVELY PHOTOTROPIC because when the tip is exposed to light auxin gathers on the shaded side and this causes cell elongation which makes the shoot bend towards the light. PLANT SHOOTS grow away from gravity so they are NEGATIVELY GEOTROPIC because when a shoot is growing sideways, gravity causes an unequal distribution of auxin in the tip so more auxin collects on the lower side. Therefore this causes the lower side to grow faster so the shoot bends upwards. ROOTS are NEGATIVELY PHOTOTROPIC meaning they grow away from light because if the roots are expose to light auxin collects on the shaded side and inhibits growth so the root grows downwards into the ground. ROOTS are POSITIVELY GEOTROPIC because they grow towards gravity because a root growing sideways will have more auxin on the lower side but because extra auxin in a room inhibits growth it means the cells on top elongate faster causing the root to bend downwards.
dkh	Plant hormones can be extracted or artificial copies can be made. These can be used to kill weeds, grow cuttings and ripen fruit. Most weeds growing in fields are broad-leaved in contrast to grasses and cereals which have narrow leaves. SELECTIVE WEEDKILLERS have been developed from plant-growth hormones which only effects broad-leaved plants. It disrupts their normal growth patterns which kills them leaving grasses and cereals untouched. A cutting is a part of a plant that has been cut off. Normally if you stick cuttings in soil they won't grow but if you add ROOTING POWDER it causes them to grow as new plants. Rooting powder contains a plant growth hormone which causes roots to produce rapidly.
Ripening & Dormancy	Plant hormones can be used to delay the RIPENING of fruit (either while still on plant or during transport). This allows them to be picked whilst still unripe so it will be less easily damaged and firmer. Ripening hormone will then be added to ripen the fruit on the way to the supermarket. Many seed won't germinate until they have gone through certain conditions. This is called DORMANCY. A hormone called gibberellin breaks this dormancy and commercial growers can treat seeds with gibberellin so they germinate at times of the year they usually wouldn't. It also helps to ensure all the seeds in the batch germinate at the same time.
Image: Capture_16.PNG (image/PNG)	Image: Capture_17.PNG (image/PNG)
Genetic Variation	Gametes are sperm cells and egg cells and are formed in the ovaries or testes. The body cells they're made up of have 23 pairs of chromosomes. In each pair, there is one inherited from mum and one from dad. When these body cells split to form gametes the chromosomes are also split up. This means that the gametes end up with half the number of chromosomes of a normal body cell - just 23. This shuffling up of chromosomes leads to variation in the new generation. Fertilization is when the sperm meets the egg to form full 46 chromosomes. But fertilization is random ans we don't know which gamete cells will join together. Mutations change the genetic code. Occasionally a gene may mutate and this can create new characteristics which increases variation.
Genes & Environment On Characteristics	Most features are determined by both genes and the environment. 1. Health - some people are more likely to get certain diseases because of their genes however, this can be effected by lifestyle. 2. Intelligence - one theory is that your maximum possible IQ is depended on your genes but whether you get this is down to your environment. 3. Sporting Ability - your genes determine your potential but training effects this too.
Alleles & Genes	Alleles are different versions of the same genes. Most of the time you have allele - one from each parent. The version of the characteristic appears depends on which whether the allele is dominant or recessive. A recessive allele is only expressed when there's no dominant allele present. If you're homozygous for a trait the two alleles will be the same (CC/cc) but if you're heterozygous for a trait, they will differ (Cc). Your genetic make up is known as your genotype. The characteristics that these alleles produce is known as your phenotype.
Punnett Squares	Image: Capture_18.PNG (image/PNG)
Genetic Disorders & Chromosome Inheritance	There are 23rd pair of chromosomes are labelled XY. They're the two chromosomes that decide whether you turn out male or female. Males - XY Females - XX There is a equal chance of having a boy or a girl even though we are talking about inheriting chromosome and not genes, a Punnett square still works. Genetic Disorders are called by faulty genes. Cystic fibrosis is a genetic disorder and is a recessive allele so that there is a 1 in 4 chance of getting it when both parents are carriers. Knowing about genetic disorders can raise difficulties about moral issues.

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	Created by Chloe Winn about 10 years ago