Biology Flashcards
(103 cards)
1
Q
What is energy generally needed for?
A
To fuel chemical reactions
2
Q
What happens to metabolic rate for people with a higher muscle to fat ratio?
A
They will have a higher metabolic rate
3
Q
Why does regular exercise boost your resting metabolic rate?
A
Because it builds muscle
4
Q
Why does your metabolic rate go up when you exercise?
A
Because you need more energy
5
Q
What do excess carbs and fats lead to?
A
Obesity
6
Q
What is obesity classed as?
A
20% over the maximum recommended body mass
7
Q
What increases cholesterol?
A
Too much saturated fat
8
Q
What increases blood pressure and risk of heart problems?
A
Too much salt
9
Q
What are the effects of eating too little?
A
Slow growth, fatigue, poor resistance to infection and irregular periods
10
Q
What are bacteria?
A
Very small living cells
11
Q
How do bacteria work?
A
They reproduce rapidly inside your body
12
Q
How do bacteria make you feel ill?
A
They damage your cells
They produce toxins
13
Q
Are viruses cells?
A
No, they are much smaller
14
Q
How big are viruses compared to bacteria?
A
Tiny, about 1/100th the size of a bacterium
15
Q
How do viruses make you feel ill?
A
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
16
Q
What about viruses make you feel ill?
A
The cell damage
17
Q
What stops a lot from getting inside the body?
A
Skin
Hairs
Mucus in the respiratory tract
18
Q
How does the body stop micro organisms from getting in through cuts?
A
Small fragments of cells (platelets) help blood clot quickly to seal wounds
19
Q
What happens if the blood contains low numbers of platelets?
A
The blood will clot more slowly
20
Q
What happens if something makes it into the body?
A
The immune system kicks in
21
Q
What fights disease in the immune system?
A
White blood cells
22
Q
What are the three ways white blood cells protect your body?
A
Consuming them
Producing antibodies
Producing antitoxins
23
Q
How do white blood cells consume pathogens?
A
They engulf foreign cells and digest them
24
Q
How do white blood cells produce antibodies against pathogens?
A
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
25
how can the antibodies white blood cells produce kill the antigens?
the antibodies produced are specific to the type of antigens
26
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
27
what do antitoxins do to protect the body against pathogens?
they counteract toxins produced by the invading bacteria
28
what do vaccinations do?
protect from future infections
29
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
30
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
31
give an example of a vaccination
MMR
32
what does MMR stand for?
measles, mumps, rubella
33
what happens if vaccinations 'wear off' over time?
you have to have a booster injection to increase levels of antibodies again
34
What are the pros of vaccinations?
1. they have helped control lots of infectious diseases
2. 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
35
what are the cons of vaccinations?
1. they don't always give you immunity
| 2. you can have side effects such as swelling, fevers or seizures, but these are very rare
36
what do painkillers do?
they relieve pain and reduce symptoms
37
what do antibiotics do?
they kill (or prevent the growth of) the bacteria causing the problem without killing off your own body cells
38
what do different antibiotics do?
kill different types of bacteria
39
do antibiotics destroy viruses?
no
40
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
41
how can bacteria become resistant to antibiotics?
they can mutate
42
what could happen if you have an infection?
some of the bacteria might become resistant to the antibiotics
43
what will happen to resistant bacteria?
they will survive and reproduce, and the population of resistant bacteria will increase
44
how can you slow down the rate of development of resistant strains?
doctors not to over supply antibiotics
45
what did semmelweis do?
he cut deaths in his maternity ward by using antiseptics as he discovered many women were dying in childbirth from puerpal fever
46
what did semmelweis believe?
that doctors were spreading the disease by not washing their hands
47
what happened when doctors started using antiseptic solution?
the death rate fell from 12% to 2%
48
what happens when someone becomes infected by resistant bacteria?
they cant easily get rid of them and they may pass the infection on to others
49
what is a stimulus?
a change in your environment/surroundings
50
what are the 5 sense organs?
```
eyes
ears
nose
tongue
skin
```
51
what are receptors?
groups of cells which are sensitive to a stimulus
52
what do receptors do?
they change stimulus energy into electrical impulses
53
what can a stimulus be?
```
light
sound
touch
pressure
pain
chemical
a change in position
a change in temperature
```
54
what receptors are in the eyes?
light receptors
55
what receptors are in the ears?
sound and balance receptors
56
what receptors are in the nose?
smell/chemical receptors
57
what receptors are on the tongue?
taste/chemical receptors
58
what receptors are on the skin?
touch
pressure
pain
temperature change
59
what are sensory neurones?
the nerve cells that carry signals as electrical impulses from the receptors to the central nervous system
60
what are relay neurones?
the nerve cells that carry signals from sensory neurones to motor neurones
61
what are motor neurones?
the nerve cells that carry signals from the central nervous system to the effector muscle or gland
62
what are effectors?
muscles and glands
63
how do muscles respond?
they contract in response to a nervous impulse
64
how do glands respond?
they secrete hormones
65
what is the central nervous system (CNS)?
where all the information is sent and where reflexes and actions are coordinated
66
what does the CNS consist of?
the brain and spinal cord
67
how does the CNS work?
neurones transmit the information as electrical impulses very quickly to and from the CNS. instructions from the CNS are sent to the effectors which respond accordingly
68
what do synapses do?
they connect neurones
69
how does a synapse work?
the nerve signal is transferred by chemicals which diffuse (move) across the gap. these chemicals then set off a new electrical signal in the next neurone
70
what are reflexes?
automatic responses to certain stimuli
71
what is a reflex arc?
the passage of information in a reflex
72
example of a reflex arc when a bee stings your finger
1. bee stings finger
2. stimulation of the pain receptor
3. impulses travel along sensory neurone
4. impulses passed along a relay neurone, via a synapse
5. impulses travel along a motor neurone, via a synapse
6. when impulses reach the muscle, it contracts
73
what happens when a stimulus is detected by receptors?
impulses are sent along a sensory neurone to the CNS
74
what generally happens when impulses reach a synapse?
impulses reach a synapse
chemicals are released
impulses are sent along a neurone eventually to the effector
75
what are hormones?
chemical messengers which travel in the blood to activate target cells
76
how long are the effects of hormones?
long lasting
77
what is produced in the pituitary gland?
FSH and LH, which are involved in the menstrual cycle
78
what is produced in the ovaries?
oestrogen, which is involved in the menstrual cycle
79
what is stage 1 of the menstrual cycle?
the uterus lining breaks down for about 4 days, bleeding starts
80
what is stage 2 of the menstrual cycle?
the lining of the uterus builds up ready for a fertilised egg
81
what is stage 3 of the menstrual cycle?
an egg is released from the ovary at day 14
82
what is stage 4 of the menstrual cycle?
the wall is maintained for about 14 days
83
3 facts about FSH
1. it is produced in the pituitary gland
2. it causes an egg to mature in an ovary
3. it stimulates the ovaries to produce oestrogen
84
3 facts about oestrogen
1. it is produced in the ovaries
2. it causes the pituitary gland to produce LH
3. inhibits the further release of FSH
85
3 facts about LH
1. its produced by the pituitary gland
| 2. it stimulates the release of an egg at around the middle of the menstrual cycle
86
what is progesterone used for?
the menstrual cycle and is produced by the ovaries
87
what can oestrogen be used to prevent?
the release of an egg, by inhibiting the production of FSH
88
what does progesterone do?
reduces fertility by stimulating the production of thick cervical mucus which stops sperm getting through
89
when was the pill first made?
in the 1950s
90
what did the first version of the pill have in it?
high levels of progesterone and oestrogen
91
what were the side effects?
blood clots due to the oestrogen
92
what does the pill now contain?
lower levels of oestrogen so there are fewer side effects
93
what happens if a woman has too low levels of FSH?
no eggs can mature
94
what can be injected by the woman to stimulate egg release in their ovaries?
FSH and LH
95
what bodily levels need to be controlled?
1. Ion content
2. Water content
3. Sugar content
4. Temperature
96
what do shoots grow towards?
light
97
what is the plant growth hormone?
auxin
98
what do shoots grow away from?
gravity
99
what do roots grow towards?
gravity and moisture
100
why do shoots grow towards the light?
more auxin accumulates on the side that's in the shade which makes the cell grow faster on the shaded side, so the shoot bends towards the light
101
why do shoots grow away from gravity?
when a shoot is growing sideways, gravity produces an unequal distribution of auxin in the tip, with more auxin on the lower side which causes the lower side to grow faster, bending the shoot upwards
102
why do roots grow towards gravity?
a root growing sideways has more auxin on its lower side, but in a root auxin inhibits growth so the top elongates faster and roots bend downwards
103
why do roots grow towards moisture?
an uneven amount of moisture either side of the root produces more auxin on the side with more moisture which inhibits growth on that side, causing it to bend in that direction, towards moisture
