Biology Flashcards
What are the issues with being overweight?
If the energy you take in equals the energy you use then your mass will stay the same. Eating too much can make you overweight and obese.
Long-term obesity can lead to health problems including type 2 diabetes (high blood sugar)
What are the 7 components of a healthy diet?
Carbohydrate Fat Protein Minerals Vitamins Water Fibre
What are the issues with being underweight?
People who don’t eat enough can become underweight (starvation).
It can lead to deficiency diseases due to lack of minerals and vitamins or can even find it hard to walk.
What does it mean to be ‘malnourished’?
If you are malnourished, it means you have had an unbalanced diet.
‘The condition when the body doesn’t get a balanced diet.’
It can lead to health complications due to lack of nutrients.
What does obese mean?
Very overweight with a BMI over 30.
How does the body control cholesterol levels?
There are 2 types of cholesterol, good and bad.
If small numbers of the cells inherit high levels of ‘bad’ cholesterol, it can lead to heart disease.
Foods rich in saturated fat can increase blood cholesterol levels.
Exercising regularly can increase their metabolic rate and lower high cholesterol levels.
(More exercise, less sat’ fat foods)
What is the link between health and exercise?
By doing regular exercise, you can increase your metabolic rate (the rate which reactions of the body take place) and lower high cholesterol levels.
This means there is a lower chance of getting heart diseases and becoming obese.
What are the main pathogens?
Bacteria
Fungi
Virus
Protozoa
What are the different methods of infection?
When bacteria or viruses enter the body, they reproduce rapidly. They make us feel ill by releasing toxins (poisons).
Viruses are much smaller than bacteria and reproduce inside cells. This damages the cell, also making us feel ill.
They can survive on surfaces, such as the skin, safely but once they enter the body, they can be harmful e.g. By open wounds.
What’s a pathogen?
They are tiny microorganisms, commonly viruses or bacteria, which cause infectious diseases.
What are the differences between bacteria and viruses?
Bacteria: Single-celled microorganisms which reproduce rapidly within the body and, although it can be useful, can cause some diseases.
Virus: Very small, smaller than bacteria, microorganisms which take over the body’s cells and reproduces rapidly, causing.
What are antibiotics and how do they work?
Antibiotics are drugs which kill infective bacteria within the body without damaging the body.
They can only kill bacteria because viruses reproduce inside the body cells so treatment can also damage the body cells.
They stop the cells from reproducing.
How do our bodies defend against diseases?
Defence mechanisms
The skin prevents pathogens getting into the body.
Mucus traps pathogens
Stomach acid kills any ingested pathogens.
The immune system - White blood cells:
Lymphocytes:
It’s a type of white blood cell made from the bone marrow.
T-lymphocytes recognise antigens and either attack directly or coordinate activity of other cells of the immune system. They can ingest pathogens, meaning they digest and destroy them. They then produce enzymes to digest them.
B-lymphocytes recognise antigens and produce chemicals called antibodies. They produce antibodies to destroy particular pathogens.
Same sized antibodies bind onto the same sized antigens but viruses can change their antigens. They produce antitoxins to counteract the toxins produced by pathogens.
What are the five sense organs?
Eyes Ears Tongue Nose Skin
What’s the order of neurones the impulse travels from the receptor to the effector?
Receptor Sensory neurone Relay neurone Motor neurone Effector
What’s a reflex arc?
A reflex arc is the nerve pathway which makes such a fast, automatic response possible.
E.g. Reacting to a flame:
Pain receptors in the finger detect the heat from the flame and send a nerve impulse to the spine, in this case through the arm, by the sensory neurone.
The impulse is then passed to the next in the spine by the relay neurone.
Finally, the nerve impulse travels down the motor neurone, in this case down the arm, to the muscle which reacts to the stimulus.
(Order: sensory neurone, relay neurone, motor neurone).
Where does growth in plants occur?
Tip of the roots and tip of the shoots.
What’s a tropism?
The turning or respond of an organism due to a stimulus, for plants it’s with light, gravity and water.
What’s phototropism?
What plants respond to light by turning to grow towards the light.
This is done because auxins are released on the shaded side of the plant shoot, causing it to grow faster than the side facing the light. (Area of elongation).
This causes the plant to grow more on one side and force the plant to bend towards the light.
What’s geotropism?
For roots and leaves to serve their purpose, they must be lower / higher.
If the plant is on it’s side, auxins gather on the lower half of the stem and root.
Auxins then are produced quickly at the top to stimulate growth in the shoot so it works against gravity and curves upwards.
On the other hand, the roots work with gravity as less auxins are released, causing it to grow slowly and downwards.
What’s a synapse and how does it work?
(As nerve cells aren’t joined together) they are the gaps between 2 nerve cells where impulses pass by diffusion of neurotransmitters to continue on the signal.
Within a neurone, an electrical impulse travels along an axon (taking information away).
This then triggers the nerve ending of a neurone and releases chemical messengers called neurotransmitters.
The neurotransmitters then diffuse (spread out) across the synapse (gap) and join themselves onto receptor molecules of the next neurone.
The receptor molecules of the second neurone only join onto specific chemicals released from the first neurone.
This then stimulates (increases activity) the second neurone to continue transmitting the electrical impulse.
What’s the menstrual cycle?
The reproductive cycle in women controlled by hormones, a cycle of ovulation and menstruation.
What are auxins?
Plant hormones
What is FSH?
Standing for follicle stimulating hormone, it is a hormone in men and women which, highest for women in the beginning and end of the menstrual cycle, causes / promotes the growth of an egg or sperm.
What’s oestrogen?
Found only in women and highest around day 12 of the menstrual cycle, it stops the production of FSH and thickens the uterus lining, promoting the characteristics of the female body.
What’s LH?
Standing for luteinizing hormone is high around day 13 of MS.
In females, an acute rise of LH triggers ovulation. It causes the egg to be released. In males it stimulates production of testosterone.
What’s progesterone?
Found in women only and high in day 24 of MS, it maintains the uterus lining and prepares for pregnancy
What’s a stimuli, receptor, effector and response?
Stimuli - change in environment
Receptor - what detects change
Effector - what brings about the response e.g. Muscles or glands
Response - the actual action in response to the stimuli
How is temperature, blood sugar and water controlled in the body?
Temperature - surroundings and physical activity
Blood sugar - food consumed
Water - food and water consumed, excreting.
What’s thalidomide and what are it’s issues?
It was a medical drug, developed as a sleeping pill, but doctors realised it could control morning sickness in pregnant women however it wasn’t tested on pregnancy.
The issue was that some babies were born with limb abnormalities due to their mothers taking thalidomide.
It was banned and resulted in rules for drug testing to be improved.
It’s recently used to treat other issues e.g. Leprosy but never to pregnant women.
What are placebos?
A substance used in clinical trials which contains no drug but is believed to in order to see how affective the actual drug is. Within the trial, half are give placebos and half are given the drugs.
What are statins?
Drugs which lower bad cholesterol in the blood.
Mainly given to older patients, it has decreased heart diseases and strokes by 40%.
What’s a ‘double-blind trial’?
A clinical trial when neither the doctor nor patient know who is given the drug. They are then asked to report sang side effects.
Some people use herbs rather than prescribed medicines e.g. For anti-depressants ‘St John’s Wort’ is used rather than Prozac. Why is the double blind trial the best way to check herbal remedies?
To see if it is as effective as a tested drug like Prozac.
What are drugs?
A chemical which causes change in the body. Medical drugs cure disease or relieve symptoms. Recreational drugs alter the state of your mind and/or body.
Why are some drugs are legal and others aren’t?
Useful drugs are made from natural substances.
Recreational drugs like heroin are very addictive and can change the brain and nervous system. - taken for pleasure.
Drugs like cannabis can lead to mental health problems.
Useful drugs have a limit or prescription.
Medical drugs are developed over many years to ensure safety.
What is the difference between prescribed and non-prescribed drugs?
Prescribed drugs are for your benefit and health and have a certain, safe amount or limit whereas non is for pleasure and can be dangerous.
What are the issues with cannabis?
It is an illegal, recreational drug and many people argue that it can lead to ‘harder’ drugs such as heroin.
There is evidence as nearly all heroin users previously smoked cannabis. Not everyone does.
How are drugs developed today?
Over many years, used to reduce pain and suffering and control disease.
What are performance-enhancing drugs?
Some athletes use them to improve performance.
Steroid are drugs which build up muscle mass, others may be used for stamina.
Strong pain killers aren’t allowed for athletes.
They are expensive.
It can damage the body or even lead to death.
Is it ethical to use performance enhancing drugs?
No,
It’s like cheating
It can lead to death
As it’s expensive, it’s unfair to those who can’t afford it.
What are withdrawal symptoms?
Symptoms experienced by drug addicts when they don’t get the drug they are addicted to.
