Biology - B1 Understanding Ourselves
notes based upon level a - a* work with some c-d notes
- Created by: Beth Lewis
- Created on: 09-04-11 09:27
Fit for life
glucose + oxygen --- carbon dioxide + water + energy = aerobic
glucose --- lactic acid + energy = anaerobic
glucose is only partly broken down in anaerobic
breathing rate = high so it can replace oxygen
heart rate = high so it can take lactic acid to live to be broken down
strength, stamina, agility, speed, flexibility = measuring fitness
blood pressure = mmHg
systolic = maximum pressure heart produces
diastolic = blood pressure between heartbeats
high blood pressure = small blood vessels bursting, brain damage, strokes
low blood pressure = poor circulation, dizziness, fainting
What's for lunch?
meat + fish = first class protiens, contain amino acids, not made by body
protien defciency = kwashiorkor
RDA protien = 0.75 x body mass (kg)
BMI = mass (kg)
height (m)
different diets for health/religious reasons, e.g jews don't eat pork
some are influenced by images in magazines
poor diets = risks of heart disease and diabetes
enzymes break down carbs, protien fats to smaller molecules, they diffuse through small intestine in to blood plasma(carbs/protiens) lymph(fats) and pass to cells
stomach makes hydrochloric acid to help enzyme pepsin work
bile helps emulsify fats because they are harder to digest and make a bigger surface area for enzymes to act on
Keeping Healthy
mosquitoes = vectors, cause malaria, parasite gets its food from host (humans)
high sugar diet can cause diabetes
low vitamin c can cause scurvy
anameia = not enough iron
symptoms are caused by pathogen making toxins
pathogens have anitgens on thier surface
white blood cells make anti-bodies which lock on and destory pathogen
active immunity = pathogen invades body 2nd time, white blood cell make antibodies, destroying pathogen before symptoms occur - CAN LAST A LIFETIME
passive immunity = antibodies given in a vaccine, lasts only a short time
antibiotics attack bacteria and fungi but not viruses
if you use antibiotics alot, it can lead bacteria to become resistant
test new drugs = volunteers take drug, some take harmless drug (placebo)
blind trial = volunteers don't know what they're talking
double blind trial = doctors/volunteers don't know what they're taking
Keeping in Touch (eyes)
binocular vision helps judge distance - range from eyes overlap
short or long sited = lens are wrong shape
red-green colour deficiency = inherited disease
accommodation = focus on light by changing lens size
distant objects = ciliary muscles relax, tighten suspensory ligaments
near objects = ciliary muscles contract, suspensory ligaments slacken lens becomes fat, fatter the lense, more light it refract
as we get older, muscle gets less flexible making it hard to focus
glasses or contact lenses can correct some eye problems
cornea surgery can also correct vision - lasers change shape of cornea
CONCAVE - inwards like a cave
CONVEX - outwards like an oval
Keeping in Touch (neurones)
motor neurones carry impulse to muscles
nerve impulse carried in axon of neurone
reflex arc
stimulus -- receptor -- sensory neurone -- nervous system -- motor neurone -- effector -- response
touching a hot plate - spinal reflex arc
neurones are adapted to quickly carry and pass on impulses
- very long (upto 2meters)
- branched endings (dendrites) to pick up impulses
- covered in sheath made from fat, to stop impulses crossing over
signals travel from one neurone to another across a gap called the synapse
Drugs and You
class A = heroin, methadone, cocaine, ectasy, LSD, magic mushrooms
class B = amphetamines, barbiturates
class C = anabolic steroids, cannabis, valium
nicotine acts as a stimulent = affects synapses
alcohol is a depressant = affects brain, co-ordination and balance
cells lining trachea and bronchioles = epithelial cells (some have cilia)
tar collects in air sacs and aveoli deep inside lungs, irritate lung tissue and are carcinogens
tiny particulates in smoke also collect in lung tissue, blocking exchange of gases and reduce oxygen for rest of body
liver breaks down alcohol, alcohol kills livercells called cirrhosis
Staying in Balance (homeostatsis)
keeping a constant internal enviroment is called homeostatsis
sweat glands make sweat and needs heat energy to evaporate
dehydration = body gets too hot
hypothermia = body gets too cold
negative feeback controls body temp,
body is kept at 37 degrees celcius = optium temp for enzymes
hypothalamus is a gland in brain which detects temp change in blood
it triggers protective measures such as changing size of blood capillaries in skin
(vasoconstriction, vasodilation)
Staying in Balance (hormones)
diabetes = pancreas doesn't make enough insulin
diabetes can be controlled by eating low sugar diet, or injection of insulin which lowers level of glucose in the blood
the size of insulin a person needs depends on diet and exercise
when glucose is too high, insulin converts some into glycogen which is stored in the liver
ovaries produce sex hormones when girls reach puberty, breasts grow, hips widen, periods start, because ovaries begin to release egg every month
testes produce male sex hormones, boys become muscular, grow facial hair and voice breaks, these are called secondary sexual characteristics
oestrogen and progesterone control the menstrual cycle, together they control ovulation
synthetic hormones are contraceptives which can stop ovulation
Gene Control
the genetic code is in a chemical called DNA
the shape of dna is called a double helix (like a ladder)
the rungs of the ladder are made up of 4 bases, in different patterns which make you
the number of chromosomes are usually even, because they seperate when eggs and sperm are formed
your body is made up of one hundred million million cells
every cell in your body has DNA, so even the cells in your hands, will have information about your eye colour.
the 4 bases of DNA are A, T, G and C, A ONLY links with T and G ONLY links with C
DNA codes for the making of a specific enzyme, these control cell reactions that produce different chemicals, therefore DNA controls what specific characteristics you have
Who am I?
All humans have 46 chromosomes, arranged in pairs
one pair of these are the sex chromosomes, females have an identical pair (**), and males have non-identical pair (XY) each sperm carries either an X or Y
Humans are all different, they show variation
Variation = genes mixed up in gametes, and changes in genes called mutations
mutations change the DNA base sequence stopping the cell making the correct protein, some are harmful whereas some are good
characteristics = dominant over others than recessive ones
monohybrid cross = one pair of characteristics, carried on a pair of chromosones, one carrying the dominant allele, one with the recessive allele
Alleles are different versions of the same gene. the dominant gene will always show up if the individual is heterozygous.
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