Biology Flashcards
What is energy generally needed for?
To fuel chemical reactions
What happens to metabolic rate for people with a higher muscle to fat ratio?
They will have a higher metabolic rate
Why does regular exercise boost your resting metabolic rate?
Because it builds muscle
Why does your metabolic rate go up when you exercise?
Because you need more energy
What do excess carbs and fats lead to?
Obesity
What is obesity classed as?
20% over the maximum recommended body mass
What increases cholesterol?
Too much saturated fat
What increases blood pressure and risk of heart problems?
Too much salt
What are the effects of eating too little?
Slow growth, fatigue, poor resistance to infection and irregular periods
What are bacteria?
Very small living cells
How do bacteria work?
They reproduce rapidly inside your body
How do bacteria make you feel ill?
They damage your cells
They produce toxins
Are viruses cells?
No, they are much smaller
How big are viruses compared to bacteria?
Tiny, about 1/100th the size of a bacterium
How do viruses make you feel ill?
They replicate themselves by invading your cells and using the cell’s machinery to produce many copies of themselves. The cell will usually then burst, releasing all the new viruses
What about viruses make you feel ill?
The cell damage
What stops a lot from getting inside the body?
Skin
Hairs
Mucus in the respiratory tract
How does the body stop micro organisms from getting in through cuts?
Small fragments of cells (platelets) help blood clot quickly to seal wounds
What happens if the blood contains low numbers of platelets?
The blood will clot more slowly
What happens if something makes it into the body?
The immune system kicks in
What fights disease in the immune system?
White blood cells
What are the three ways white blood cells protect your body?
Consuming them
Producing antibodies
Producing antitoxins
How do white blood cells consume pathogens?
They engulf foreign cells and digest them
How do white blood cells produce antibodies against pathogens?
the white blood cell comes across a foreign antigen (its unique molecule)
it produces proteins called antibodies which lock onto and kill the invading cells
antibodies are then produced rapidly and are carried around the body to kill all similar viruses or bacteria
how can the antibodies white blood cells produce kill the antigens?
the antibodies produced are specific to the type of antigens
what happens if a person becomes infected with the same pathogen again?
the white blood cells would rapidly produce the antigen to kill it - they are naturally immune to it
what do antitoxins do to protect the body against pathogens?
they counteract toxins produced by the invading bacteria
what do vaccinations do?
protect from future infections
what happens when a new microorganism infects the body?
it takes the white blood cells a few days to learn how to deal with it, by this time you can be very ill
how do vaccinations work?
they involve injecting small amounts of dead or inactive microorganisms into the body
these carry antigens which the body produces antibodies to attack them even though it is harmless
if the microorganism enters your body again, your body rapidly mass produces antibodies to kill it so you are immune
give an example of a vaccination
MMR
what does MMR stand for?
measles, mumps, rubella
what happens if vaccinations ‘wear off’ over time?
you have to have a booster injection to increase levels of antibodies again
What are the pros of vaccinations?
- they have helped control lots of infectious diseases
- big outbreaks of disease (epidemics) can be controlled if a large group are vaccinated (herd vaccinations) so there are less people to pass it on and it wont spread as quick
what are the cons of vaccinations?
- they don’t always give you immunity
2. you can have side effects such as swelling, fevers or seizures, but these are very rare
what do painkillers do?
they relieve pain and reduce symptoms
what do antibiotics do?
they kill (or prevent the growth of) the bacteria causing the problem without killing off your own body cells
what do different antibiotics do?
kill different types of bacteria
do antibiotics destroy viruses?
no
why is it difficult to produce a drug which stops viruses?
because viruses reproduce using your own body cells so it is difficult to develop drugs that destroy the virus without killing your body cells
how can bacteria become resistant to antibiotics?
they can mutate