a balanced diet
a balanced diet has correct amounts of:
the body uses carbs, prteins and fats to release energy that is needed for living and making new cells.
vitamins and minerals are needed to keep the body working healthily.
an unbalanced diet causes malnourishment, and no vitamins and minerals causes deficiencies.
the amount of energy you need depends on many things.
males need more energy than females.
pregnant females need more energy than males.
teenagers need more energy that someone who is 80
athletes have more muscle than other people and muscle tissue transfers more energy than fat, therefore athletes need more energy.
temperature also effects the amount of energy you need, e.g. in anarctica someone needs to use much more energy to keep warm thatn someone in mexico.
the metabolic rate is the rate of chemical reactions in the cells.
men usually have a higher metabolic rate than women, because they have more muscle than fat.(muscle is built up by exercising more)
some people think your inherited factors effect your metabolic rate (e.g. from your parents or grandparents)
this is why some people have a much higher metabolic rate than someone who is very similar to them.
if your energy input is greater than your output, the excess energy is stored as fat. some body fat is essential to cushion your internal organs but excess fat is a form of malnourishment.
too much fat causes someone to become overweight or even obese. this can lead to serious problems such as type 2 diabetes, arthritis, high blood pressure and heart disease.
you loose mass when you energy output is greater than your input.
mass can be lost by curring back on food, doing more exercise or doing both!
deficieny diseases in impoverished countries are common, a lack of mineral ions and vitamins are not unsual in a place which hasnt got enough food.
health and exercise
inherited factors from parents affect appearance as well as your healthm they affect your metabolic rate, risk of heart disease and your proportion of muscle to fat.
the way your body controls cholestrol is one example of an inherited factor, cholestrol is needed for cell membranes and hormones, but there are 2 types of cholestrol; good and bad.
if the balance of your cholestrol levels is wrongm your risk of heart disease increases.
eating a lot of high fat food increases the likelihoood of having harmful cholestrol, but 1/500 people inherit factors which means they have harmful cholestrol no matter what they eat.
exercising regularly can lower your blood cholestrol levels.
an infectious disease is caused by a mocroorganism attacking your body, the tern infectious is where it is passes from one thing to another,
these microorganisms are calles PATHOGENS. bacteria and viruses are common pathogens.
bacteria are single celled, and are much smaller than animal.plant cells.
viruses are even smaller and have regular shapes. they can even cause disease in bacteria!
once these pathogens are in your body they reproduce rapidly, bacteria split in 2 and viruses use your own body cells as hosts, sometimes creating toxins.
the damage caused causes headached and rashes and other effects, as well as a high temperature.
Ignaz Semmelweis realised about infectious pathogens and told doctors to wash their hands (in the mid 1850s)
droplet infection is when you cough sneeze or talk, and expel droplets of pathogens onto others.
direct contact is exactly what it sounds like.
contamination of food and drink e.g. from raw food.
through a break in your skin.
your skin is one barrier of your body and stops pathogens getting in to the tissues.
scabs over wounds is also a defence mechanism which stops pathogens getting in.
mucus traps the pathogens and is then expelled or swallowed and destroyed by the acid in your gut.
white blood cells
some pathogens can bypass the body defences and get inside, the White blood cells are the backup form of defence.
some ingest pathogens and destroy them.
some produce antibodies that target pathogens and destroy them
some create antitoxins whcih counteract the toxins.
painkillers help to relieve the symptoms but do not effect the pathogens, they just help with the symptoms.
antiseptics and disinfectants kill bacteria but would also kill your body!
antibiotics work inside your bodym and kill the bacteria.
they damage bacterial cells without hurting your cells nut they do not effect viruses because theu are inside your own cells!
Alexaner Fleming discovered penicillin but couldnt prove its usefulness.
ernst chain and howard florey could, and managed to mass produce it.
the nervous system
your nervous systema llows you to react to your surroundings through the use of impulses. it reacts to stimuli using receptors:
- balance (in ears)
the info is sent along neurons which are bunched together as nerves, the CNS (central nervous system) is the brain and spinal cord and sensory neurons carry impulses to your CNS from the sense organs.
motor neurons make effector organs respnd, e.g. you hand muscles. they are muscles or glands.
the order is; receptor-sensory neuron-snc-motor neuron-effector organ
reflexes help to avoid danger or harm and are subconscious.
there are 3 types of neron involved, sensory motor and relay. this ends at an effector organ and is called the reflex arc.
your nerves are joined by synapses, whcih are actually gaps where chemicals are released to let the impulses travel along.
a reflex action goes as follows: stimulus-receptor-coordinatir-effector-response
hormones are made in glands and are chemicals that coordinate processes in your body.
a womans menstrual cycle is an example of hormonal control.
the cycle lasts 28 days,
- after 14 days the egg matures and in released from the ovary (ovulation) while the womb lining stays thick.
- [if the egg is fertilised pregnancy takes place.]
- the egg and womb lining are shed (period)
FSH is made by the pituitary gland and makes eggs mature as well as stimulating production of oestrogen.
oestrogen is made by the ovaries and stimulates the womb lining to build up as well as inhibiting the production of FSH
luteneising hormone and progesterone are also involved.
artificial fertility control
oral contraceptives are one of the most widely used fertility controls (the contraceptive pill [the pill])
the pill contains female hormones, mainly oestrogen, which prevents the release and maturing of eggs. the pill must be taken regularly or the bodies hormones take over very fast.
fertility can also be promoted, FSH can be used as a fertility drug to stimulate the eggs to mature and produce oestrogen aswell.
the drugs are also ised in in vitro ferilisaton-IVF.
thee egg is externally fertilised and developed into a tiny embryo and then iserted into the mothers womb.
the internal evironment in your body needs to stay constant to keep your body working properly, this is known as homeostasis.
it involves controlling the concentraion of mineral ions like salt and the amount of water in your body. too much water or too little water can easily destroy your cells.
you gain water from food and drink and lose it in uring from the kidneys (and also gain/lost mineral ions). your kidneys change the amount of salt and water lost.
temperature is set at 37C in your body, because the enzymes are at their prime. you shiver to warm up and sweat to cool down.
the pancreas makes hormones to control the glucose levels in your blood (blood sugar) so that your cells have a constant supply of energy.
auxin is a vital plant growth hormone. it makes sure the roots grow down and the shoot grows up! this is so that the plant is anchored absorbs water and minerals and also photosynthesises.
photo-tropism is where the auxin in the shoot is more on the side without light, and the plant grows faster on the side with more auxin and faces the light.
gravitropism ((geotropism)) is where the auxin the the root grows on the side with more gravity/facing down, the plant then grown faster on the side with the leas auxin and grows down!
a good medicine is effective, dafe, stable and successfully moved around your body-in and out.
money and time are needed to make a new drup, up to 12 years and £350 million.
the medicine is tested on cells tissues and organs, then on living organisms (animals), then on healthy humans and on unhealthy humans.
in a double blind trial the doctor nor the patient know if they have the placebo.
we thoroughly test drugs because drugs like thalidomide was not safe for fetuses and caused deformities .
a drug alters the way your body works. they are used for medicine or pleasure.
coffee, tea, wine, beer are all drugs they have caffeine and alcohol but are all legal.
cocain, heroin and ecstacy are some illegal drugs, they cause great harm by affecting your body chemistry.
you can become addicted -dependent- on a drug. when you stop taking the drug you are vulnerable to withdrawal symptoms such as pain, sweating, shaking and headaches.
steroids and the like
anabolic steroids are drugs that help to build up muscle mass and are used for strong athletes such as weightlifters.
painkillers allow people to work with injuries but this can cause even more damage.
cyclists use drugs that make their body make more red blood cells.
adapting to survive
plants need light, CO2, H20, O2 to produce energy.
animals need food.
mocrooganisms need a range of things.
plants need to photosynthesis and get enoguh water to their cells. epiphytes have adaptations to live high above ground and collect water and nutrients from the very air, using special leaves. rafflesia arnoldii produce flowers which smeel like a rotting corpse to increase the chance of flies.
animales need food, there are herbivoes, carnivores and omnivors. herbivores have flat teeth to grind up plants, carnivores ave sharp teeth to tear flesh.
come birds have glands that "cry" to release salt out of the bodym some animals have an antifreeze chemical in their cells, some plants have air spaces in leaves to float, and some extremopholes live in the harshest environments, thermophiles survive a tover 80C, or down to -15C.
the amount of energy you lose is linked tour surface area to volume ration (SA:V) the bigger tha animal the smaller the ratio, so the smaller the energy loss. cold environments have big animals which have a small SA:V so they lose less energy.
animals also have afat layer to live through the winter when there is no food, some have blubber to keep them warm.
other animals have camouflage to make them harder to see, to stay away from predators or to hunt their prey.
the SA:V ratio is vital in plants, to stop water loss through the leaves.some desert plants have huge leaves shich collect the dew and funnel it to their shallow roots.
some plants have curled leaves to trap a layer of moist air, to reduce water loss via evaporation. cacti have spikes to deter animals.
some animals have giant root sytems which reach deep down, or wide across to take up as much H2O as possible.
cacti store water in their water storing tissue with their small SA:V ratio, making them very successful.
animals compete for food territory and mates.
herbivores feed on splants, sometimes one or two and sometimes on hundreds, there are thousansa of grass eating herbivores!
carnivores compete for prey, so the best adapted predator will be the most successful.
intraspecific competition (the same species) is mich more intense than intraspecific competition.
prey also compete to escape.
animals defend territory to make homes as well as to fin a mate.
plants compete for light, water, nutrients and space.
they compete so that they can survive, sometimes even with their own offspring (seedlings).
some plants flower very early in the year when light gets through the abre branches of the trees.
some plants have deep roots to absorb water deep undergrounds.
plants need to avoid competition with their own seedlings so they spread seeds with the helps of animals which eat the fruit, with the helkp of wind or just throug mini explosions.
solar energy always pours onto the earths surface.
green plants absorb this energy with chlorophyll.
herbivores eat the plants.
carnivores eat the herbivores.
in a food cahin, there are usually more producer thant there are primary consumers and more primary consumers that secondary consumers etc etc.
a pyramid of biomass is a scale representation of the transfer of biomass. a pyramid of numbers is usually inverse to a pyramid of biomass.
energy transfers and decay
energy is lost as it goes up the pyramid.
itis lost in waste, in movement and in body temperature. to keep the animal alive it moves around and stays warm, which makes it constantly use energy.
everything eventually dies, decomposers then break down the waste and dead organisms in the process of decomposition.
detritus feeders like worms eat dead animals and produce waste mateial.
bacera/fungi then digest everything and also release waste. (CO2, H2O and nutrients)
decay is optimal in warm, moist conditions with plenty of O2 available.
we inherit factors from our parents, through the gametes.
the genetic info is carried in the nucleus of cells, inside chromosomes which are made up of DNA, which is in the form of a double helix.
humans ave 46 chromosomes, 23 pairs, in each body cell.
each chromosome has thousands of genes, 20-25000 genes!
the genes are passed through Asexual or sexual reproduction.
asexual reproduction results in clones while sexual reproduciton has variation.
nature VS nurture is the different factors, e.g. height can depend on nurture(Environment) while skin colour depents on nature(genetic).
by taking cuttings from plants new plants can be grown. hormone rooting powder helps cuttings successfully develop.
tissue culture is a new way of cloning plants. it is more expensive but lets you make 1000s of new plants identical to the original plant.
using plant hormones and some cells from the plant to make a lot of cells then make each cell to form a new plant.
animals are cloned when an early embryo (celll cluster) is split up, then allowed to grow into identical embryos then given to surrogate somthers then born to make identical animals,
in an adult cell; the nucleus is removed form an egg cell and another cells nucleus is implanted with an electric shock to make it divide then it is inserted into a surrogate mother and is born to form an adult clone.
by splicing genes, scientists can make hugely beneficial creations.
thake the gene out of DNA with an enzyme and insert it into a plasmid with another enzyme then insert it into a bacterium and let it multiply. this can be used e.g. with insulin to make bacteria which produces insulin.
this can be done to animal and plant cells to make them act differently, e.g. making a normal fish glow. with this we can make what we need in a pure form.
GM foods are modified foods such as a rice high in vitamin A, which makes it much easier to get the nutrients and minerals that we humans need to survive,
jean-Baptiste Lamarck thought is an animal used something a lot it would evolve and pass to the offspring e.g. the neck of a giraffe, but he thought the fountain of life linked the species.
Darwin had the right theory and millions of years was required for evolution of a whole species and survival of the fittest with natural selection deciding what survives.
we use kingdoms to classify a group of organisms, whciha re broken down into smaller species.
they are classified using DNA evidence and similarities in the DNA, unlike before where appearance was used.