1a) Human Biology Flashcards
What is your metabolic rate?
The speed at which chemical reactions occur in the human body.
Explain why the body needs each food group.
Carbohydrates - release energy
Fats - keep warm, release energy
Protein - growth, cell repair and cell replacement
Fibre - smooth digestive system
Vitamins/mineral ions - skin, bones blood
Define malnourishment
Someone who’s diet is badly unbalanced ( they can be fat or thin)
Define obesity
Health problem of bring 20% or more over maximum recommended body mass
What is arthritis?
Inflammation of the joints
What is type 2 diabetes?
Health problem with the inability to control blood sugar level
What is the result of having too much saturated fat in your diet?
Increase your blood cholesterol level
What are some of the effects of malnutrition?
Slow growth (in children)
Fatigue
Poor resistance to infection
Irregular periods in women
What is scurvy?
A deficiency disease of vitamin C that causes problems with skin, joints and gums
How dies exercise affect the body?
Increases amount of energy used by body
Decreases amount of energy stored as fat
Builds muscle to boost your metabolic rate
What 3 things does your health depend on?
Unbalanced diet
Exercise
Inherited factors
Define a pathogen
Microorganisms that enter the body and cause infectious diseases
Name the two main types of pathogen and describe them
Bacteria - small living cells, reproduce rapidly, damage your cells and produce toxins
Viruses - not cells, smaller than bacterium, replicate themselves by invading cells, cell damage makes you feel ill
Name 3 ways your white blood cells attack invading microbes
Engulf foreign cells and digest them
Produce antibodies (proteins) to lock onto and kill invading cells
Producing antitoxins to counteract toxins produced by bacteria
What is a vaccination?
Small amount of dead or inactive microorganism injected into a body
Carry antigens which stimulate white blood cells to produce antibodies to attack them
If live microorganisms reappear, white blood cells can rapidly mass-produce antibodies to kill pathogen
What does MMR stand for?
Measles, Mumps, Rubella
What are the advantages and disadvantages of vaccination?
Pros:
Control infectious diseases - smallpox no longer occurs
Epidemics prevented
Cons:
Don’t always work
Can sometimes have a bad reaction to a vaccine
What is the difference between painkillers and antibiotics?
Painkillers - relieve pain, reduce the symptoms (Don’t tackle disease)
Antibiotics - kill or prevent growth of bacteria (but not viruses)
Why DON’T antibiotics destroy viruses?
Viruses aren’t living cells
They reproduce using host cells
It is hard to kill just the virus and not your own body cells
Name 3 things to remember when growing microorganisms in a Petri dish
Equipment must be sterilised (e.g. passing an inoculation loop through a flame) to prevent unwanted microorganisms to affect the result
Petri dish must have a lid taped on to stop microorganisms in the air contaminating the culture
At school temp if culture should be kept at 25 degrees Celsius so harmful pathogens won’t grow
What is a stimulus?
A change in your environment
Name the 5 sense organs and their receptors
Eyes - light receptors
Ears - sound receptors, balance receptors
Nose - smell receptors
Tongue - taste receptors
Skin - sensitive to touch, pressure, pain and temp change
What is a receptor?
Groups of cells sensitive to a stimulus
They change stimulus energy into electrical impulses
Describe the role of the central nervous system
Where info from sense organs is sent through neurones (nerve cells) and reflexes and actions are coordinated
Made of brain and spinal cord
What is an effector?
Muscles and glands which respond to a nervous impulse
What is a synapse?
The connection between two neurones ( nerve cells)
How does information transfer across a synapse?
The nerve signal is transferred by chemical which diffuse across the gap
These chemicals set off a new electrical signal in the next neurone
What is a reflex?
An automatic response to a certain stimuli
What is a reflex arc?
The passage of information in a reflex
Describe what happens in a reflex arc
Stimulus is detected Receptors send nerve signals along Sensory neurone to Relay neurone to Motor neurone to Effector which brings about the Response
How is information transferred around the body?
Through neurones ( nerve cells) as electrical impulses Through hormones (chemicals) in blood secreted by glands
What are hormones?
Chemical messengers secreted by glands carried in the blood plasma to activate target cells
What are the differences between hormones and nerves?
Nerves: fast reaction, act for a short time, act on a very precise area
Hormones: slower reaction, act for a long time, act in a more general way
What is the menstrual cycle?
Monthly release of an egg from a woman’s ovaries
Build up and break down of lining in the uterus (womb)
Describe the menstrual cycle
D - lining breaks DOWN on day 1
U - lining builds UP on day 4
R - egg is RELEASED on day 14
M - lining is MAINTAINED on day 28
Cycle repeats
What are the 3 main hormones involved in the menstrual cycle and where are they produced?
FSH (Follicle Stimulating Hormone): produced by pituitary gland
Oestrogen: produced in ovaries
LH (Luteinising Hormone): produced by pituitary gland
(progesterone: produced by ovaries)
What does each hormone invoked in the menstrual cycle do
FSH: causes egg to mature in ovaries, stimulates ovaries to produce oestrogen
Oestrogen:causes pituitary produce LH, inhibits further release of FSH
LH: stimulates release of egg around middle of cycle
How can hormones be used to reduce fertility?
Oestrogen - prevent release of egg by inhibiting production of FSH
Progesterone - stimulates production of thick cervical mucus which prevents any sperm reaching an egg
What is the pill?
Oral contraceptive with high levels of progesterone and oestrogen ( known as combined oral contraceptive pill)
What are the pros and cons of the pill?
Pros: over 99% effective at preventing pregnancy, reduces risk of getting some types of cancer
Cons: not 100% effective, side effects, doesn’t protect against STDs
Why would a woman with low levels of FSH find problems with getting pregnant?
Little FSH to cause eggs to mature
No eggs released and woman can’t get pregnant
How can the hormones FSH and LH increase fertility?
Hormones injected into woman
Stimulates egg release in ovaries
More chance if pregnancy
What are the negatives of injecting FSH and LH to increase fertility?
Doesn’t always work - may need it multiple times which is expensive
Too many eggs could be stimulated causing unexpected multiple pregnancies (twins, triplets etc.)
What is IVF?
In Vitro Fertilisation
Collect eggs and fertilise them in a lab using a man’s sperm
Grow them into embryos
Embryo transferred to uterus
What are the pros and cons of IVF?
Pro:infertile couple can have a baby
Cons: could have strong reaction to hormones, reports of increased risk of cancer, multiple births
What is an auxin?
A plant growth hormone that controls growth near the tips of roots and shoots
Responds to light (phototropism), gravity (geotropism) and moisture
What happens if the tip of a shoot is removed?
No auxin is available
the shoot may stop growing
How does auxin promote the growth of plants?
Auxin is produced in the tips
Moves backwards/builds up on one particular side
Stimulates cell elongation
Plant grows
How can plant hormone be used in agriculture?
In selective weed killers
In rooting powder adding to soil - promotes plant cuttings to grow
