Zusammenfassung der Ressource
Biology Unit 1 Part 1
- Diet , exercise and health
- Metabolism
- Chemical reactions in cells are
collectively called this
- The rate at which the
chemical reactions happen is
called your METABOLIC
RATE
- Variation of
metabolic rates
- Exercise
- Muscles contract more to move
limbs so they need more
energy
- Cells need to respire more to
release more energy from
glucose so you eat more
- Exercise increase the
amount of energy
expend by the body , so
the metabolic rate is
higher
- Proportion of muscle
to fat
- Fat cells store fat and they are
inactive - low rate of respiration to
ensure they don't lose their fat
- Muscles ells are active - high
rate of respiration to ensure
they don't lose their stored fat
- More muscles and less
fat = high metabolic rate
- More fat and less muscle = low
metabolic rate ( need to eat more
food to supply energy for muscle cells
- Inherited factors
- Tall people (higher metabolic rate) -
lose more heat from body surface
- Overweight people (higher metabolic
rate) - larger bodies need more energy
to move
- Underactive thyroid gland -
lower metabolic rate
- A balanced diet contains the right amount
of different foods and the right amount of
energy to keep you healthy
- Carbohydrates for energy
- Fats for energy
- Proteins build cells
and reaper tissues
- Water (cells contain about 70%
of it) is lost in sweat and urine
etc.
- Fibre prevents
constipation
- Mineral and ions - small amounts
keep the body healthy
- Malnourishment
- A person's diet isn't balanced - too fat
or too thin
- Can lead to
deficiency
disease
- Lack of vitamin D - rickets ( soft
bendy bones , curved spine ,
enlarged skull)
- Underweight
- Energy of the content of the
food you eat is less than the
energy you lose
- Don't eat enough or exercise to
much
- Thin girls - irregular periods
- Overweight
- If people too much
- Very overweight = obese
(can cause type 2
diabetes)
- Inherited factors can
also affect cholesterol
levels
- Cholesterol
- Helps strengthen cell
membranes , and used to
make sex hormones and
vitamin D
- To much can increase the risk
of heart disease
- Comes directly from meat , prawns
and eggs
- Liver makes it from saturated fats in
butter , chocolate and fatty meat
- Liver can make too much - take satins to
reduce levels , taken in the evening as the
body makes it during the night and it inhibits
an enzyme involved in making cholesterol
- Infectious diseases
- Antibiotics and painkillers
- Painkillers only relieves pain it
doesn't kill pathogens
- Antibiotics kill infective bacteria
inside the body (Penicillin)
- Specific antibiotics target specific
bacteria
- Cannot be used to kill viruses
- Drugs called antivirals stop your
cells a making copies of the viruses
- They stop bacteria from
making cell walls or protein
and viruses don't do this
- Resistance
- MRSA
- Bacteria is resistant to methicillin
(very strong antibiotic)
- Caused many deaths
- Lives in the skin but if it gets into a
wound it causes harm
- Easily killed with antiseptics and
disinfectants
- 1. Bacteria infect you
- 2. One or two may have
chance mutations and aren't
killed by the medicine
- 3. New strain of bacteria that is
resistant to antibiotics have
developed
- Immunity and immunisation
- Body has barriers to stop
pathogens entering it
Anmerkungen:
- Skin , stomach acid , tears , blood clotting and mucus in the airways
- White blood cells
- Phagocytes - engulf
(ingest) pathogens
- Lymphocytes - produces
antibodies or antitoxins
- Antibodies
are proteins
- Each pathogen has particular
antigens (proteins) wit ha specific
shape on its surface
- Each type of antibody also has a particular
shape which can lock onto the antigen
- Immune system makes the right
antibodies
- Once the pathogen is coated with antibodies ,
white blood cells can ingest and kill the
pathogen
- Once recovered you are immune as your body knows
how to make the right antibodies
- Immunisation
- Reduces the
spread of
infection
- Flu virus - Mutates often so
body doesn't recognise
antigens (epidemic and
pandemic)
- 1. Small amount of dead or inactive pathogen is
introduced to the body by an injection - still have
antigens on surface
- 2. White blood cells respond by making
antibodies
- 3. If live pathogens enter the body
the white blood cells can quickly
make the correct antibodies
- 4. Destroying the pathogens before
you get ill
- Preventing them
from spreading
- Ignaz Semmelweis
- Asked doctors wash
hands between procedures
( dealing with dead and
delivering babies)
- Reduced deaths
(MRSA)
- Pathogens
- Any microorganisms that can
cause an infectious disease
- Bacteria
- Not all pathogens
- Have millions on our skin or
in our gut
- If they get into our blood or cells
they can make us very ill
- Reproduce rapidly in our warm
bodies
- Produce toxins that make
us ill and can cause death
- Viruses
- All pathogens
- Insert themselves into a host
and hijack the cells parts to
make copies of the virus
- New virus particles then burst out of cells an
infect other cells - chain reaction
- Viruses damage and destroy cells
- Much smaller than bacteria
- Not made of cells and cannot carry out
any life process so they are thought to not
be alive
- The nervous system
- Needs to be able to
respond to changes in the
environment called stimuli
- Used to avoid
danger
- Structure
- CNS (central nervous
system) is the brain and
spinal cord
- Peripheral nervous system -
nerves taking information
from sense organs to CNS
and nerves taking information
from CNS to effectors
(muscles or glands)
- Sense organs or receptors
- Special cells adapted to detect
stimuli
- Have nucleus , cell membrane and
cytoplasm
- Information passes from them as electrical
impulses along nerve cells called neurone to
the brain
- Brain then co-ordinates response
- Adaptations of neurones
- Long
- Insulating sheath - prevents
impulses from leaking
- Branched ends - communicate with
other neurones
- Reflex arc
- 1. The stimulus - pin prick
- 2. Pain receptors in the skin
are stimulated
- 3. A nerve impulse (electrical) travels along
the sensory neurone to the relay neurone
- 4. Then the impulse passes through
a synapse to the brain
- 5. The impulse travels along
the motor neurone
- 6. The nerve impulse then travels to
effector
- 7. The muscles contract pulling
the finger away (the response)
- Chemical reaction by diffusion
- Effectors
- Either muscles responding by
contracting
- Glands responding by
secreting chemical
substances
- Hormones and control of the body
- Are chemicals
- Body usually reacts slowly
to them
- One that acts is quickly when the kidneys
regulate water content of blood
- They regulate the functions of many
organs and cells
- Coordinate many processes in the body
- Are produced (secreted) from glands into
the bloodstream
- Travel in the blood to target organs
- Water
- Loss
- From skin in sweat
- Lungs by
breathing out
- Kidneys in urine
- Gain
- From drinks and food
containing water
- Respiration of digested food
- Kidneys help to
regulate levels
- One hormone helps the kidney to only
pass out water when you have too
much
- Blood sugar level
- Hormones
regulate blood
sugar
- Products of
digestion pass
into
bloodstream
and are carried
to cells
- Ion content
- Sodium , potassium ,
magnesium , calcium
and hydrogen
- Help your nerves
work and keep your
body funds at the right
pH
- Pass out any
unwanted in urine
- Hormones work with kidneys
to make sure the balance of
these ions is right
- Temperature
- Has to be kept
around 37 degrees
- Chemical reactions happen
quick enough
- Too high/too low -
enzymes stop working
(chemical reactions
such as hormones stop
working)
- Get rid of heat by sweating
- Warm blood flows near the
surface of the skin
- Menstrual cycle
- Contraception
- Pills contain oestrogen and progesterone to
prevent FSH from maturing the egg
- Controlling fertility
- IVF - test tube baby
- Benefits
- Infertile couples can have children
- Embryos can be screened for
genetic diseases
- Choose when to have kids
- Wait until they can afford a family
- Limit family size or they might not want children
- Problems
- Religious - playing God
- Embryos made cannot develop
- Should adopt instead
- Expensive
- Side-effects (weight gain , mood swings)
- Inject mother with FSH and LH
which causes ovaries to make
more eggs than usual
- Eggs collected from mother and
fertilised by fathers sperm
- When eggs developed into
embers , two are chosen and
inserted into the mothers womb
- Pituitary gland in brain produces
FSH
- FSH causes eggs in ovaries to mature
and stimulates ovaries to make oestrogen
- Oestrogen stimulates the pituitary
gland to LH
- LH triggers the release of an egg
(ovulation) from the ovary
- Oestrogen prevents more FSH being
secreted and repairs the uterus lining
- Progesterone maintains the uterus lining and
works with oestrogen to prevent the secretion of
FSH
- If the egg isn't fertilised the uterus lining
passes out of the body
- Lining stays so the baby can develop if the
egg is fertilised
- Controlling plant growth
- Auxin - plant hormones
- Uses
- Weed killers - use too
much hormones
- Rooting powder - helps
cuttings to make new roots
- Fruit ripening -
prevent fruit from
dropping
- Control of dormancy - stop seeds
from germinating in winter
- Tropism - response
to stimulus
- Geotropism
- Response to gravity
- Shoots grow up -
negatively
- Roots grow down -
positively
- Auxins aid growth of cells
- Top grows faster than bottom
- Bend downwards
- Phototropsim
- Plants grow towards
the light this is called
positive phototropic
response
- Light shines on the shoot
and the auxins move to the
shaded side
- Cells on the shaded side
grow faster and the plant
bends towards the light
- Drugs and you
- Testing new drugs
- 1. New drugs are tested in laboratories on human tissues and
animals to see if they work and find out how toxic they are
- 2. If they pass these trials they are tested in
humans in clinical trials
- 3. Low doses are given to volunteers
- 4. Volunteers are divided into two
groups
- 5. Double blind trial - no one knows
who has what drug , fair and results
can't be biased
- 6. Two groups compared
- 7. If the drug makes a real difference and
causes no harm it is licensed for use
- 8. Side-effects mean drugs are
recalled
- Control group are
given a placebo or
dummy pill
- Experiment group
are given the real
drugs
- Drugs are tested vigorously
- Thalidomide - morning sickness
drugs that caused babies to be
born with short limbs
- Beneficial drugs (painkillers
or antibiotics)
- Perscribed by doctors
- They may have
side-effects
- Could interfere with other
medication
- Be harmful to a
particular patient or if
taken too often
- Recreational
- Illegal
- Cannabis
- Very good painkiller -
multiple sclerosis
- Lead to
mental health
problems
- Addiction to harder
drugs (heroin and
cocaine)
- Increase risk of
heart attacks and
strokes
- Performance enhancing
- anabolic steroids
- Withdrawal
symptoms
- Leads to
harder drugs
- Legal
- Tobacco ,
caffein ,
alcohol
- Nicotine -
addictive and
causes cancer
- Alcohol - damages nervous
system and alters behaviour