Biology Flashcards
(107 cards)
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.
