Paper 1 Flashcards
(360 cards)
1
Q
name the five parts of the animal cells
A
Cell membrane
Nucleus
Cytoplasm
Mitochondria
Ribosome
2
Q
name the 3 extra parts of the plant cells
A
vacuole
cell wall
chloroplasts
3
Q
what is the function of the cell membrane?
A
Controls what enters and leaves the cell
4
Q
what is the function of the nucleus?
A
contains the DNA of the cell and can control the cell
5
Q
what is the function of the cytoplasm?
A
where the reactions take place
6
Q
what is the function of the ribosome?
A
creates proteins
7
Q
what is the function of the cell wall?
A
helps the cell keep its shape
8
Q
what is the function of the vacuole?
A
contains cell sap, helps keep the shape of the cell
9
Q
what is the function of the chloroplasts?
A
where photosynthesis
10
Q
what type of cells are plant and animal cells
A
eukaryotic cells
11
Q
what are eukaryotic cells?
A
cells that have a nucleus and membrane-bound organelles
12
Q
what type of cells are bacterial cells
A
prokaryotic cells
13
Q
what are prokaryotic cells?
A
cells that don’t have a nucleus
14
Q
what are the 7 structures of bacterial cells?
A
chromosomal DNA
Ribosomes
plasmids
cytoplasm
cell wall
flagellum
cell membrane
15
Q
what is chromosomal DNA
A
a single loop of DNA that lies free in the cytoplasm, which carries most of the bacteria’s genes
16
Q
what is a plasmid?
A
extra circles of DNA, which contain extra genes not found in chromosomal DNA
17
Q
what is the function of a flagellum?
A
helps the bacteria move
18
Q
give 3 specialised animal cells
A
egg cell
sperm cell
nerve cell
red blood cell
white blood cell
19
Q
give 3 specialised plant cells
A
root hair cells
palisade cells
xylem cells
20
Q
give a specialised feature of a root hair cell
A
have a large surface area which allows for a higher rate of absorption
have more mitochondria to allow for active transport
21
Q
give a specialised feature of a palisade cell
A
are towards the top of the leaves
have more chloroplasts to allow for photosynthesis
22
Q
give a specialised feature of a xylem cell
A
have thick cell walls to help keep the structure of the plant
23
Q
give a specialised feature of an egg cell
A
have a haploid nucleus
can prevent any more sperm cells from entering after being fertilised
24
Q
give a specialised feature of a sperm cell
A
- have a flagellum for movement
- have a midpiece filled with mitochondria which give the cell energy to move around
- have an acrosome with enzymes that helps the sperm cell enter the egg cell
- haploid nucleus
25
give a specialised feature of a nerve cell
are thin and long which allow them to carry message over a long distance
have a myelin sheath which insulates the electrical signal
26
give a specialised feature of a red blood cell
- don't have a nucleus so have more space to carry oxygen
- contain haemoglobin to carry oxygen
- Biconcaves have a large surface area, which gives them the best chance of absorbing as much oxygen they can in the lungs
27
what are the 2 types of microscopes?
light microscope
electron microscope
28
what is the greatest possible magnification from a light microscope?
x2000
29
what is the greatest possible magnification from a electron microscope?
*10 million
30
what is the formula for calculating magnification?
Magnification = Image Size / Real Size
31
how to get from mm to um
*1000
32
what is the equation for total magnification?
total magnification = eyepiece magnification * objective lens magnification
33
what are the 4 small units of measurements?
millimetres
micrometres
nano metres
picometres
34
how do you get from micro metres to pico-metres
*1'000'000
35
what are enzymes
enzymes are biological catalysts that speed up reactions in the body without being used up themselves.
36
why do enzymes only work with specific substrates?
because the shape of the active site is made to fit only one type of substrate
37
what 3 factors affect the activity of enzymes
temperature
substrate concentration
PH
38
how does temperature affect the activity of an enzyme?
-if the temperature is too low, there is not a lot of kinetic energy which means less successful collisions will happen between the substrate and the active site, and the substrate will take longer to fit into the active site
-I the temperature is the optimum temperature, the enzyme will be working at its fastest rate
- too high of a temperature will cause the enzyme to denature which is where the shape of the active site changes, this can cause the substrate to no longer fit into the active site, which will lower the rate of reaction
39
how does substrate concentration affect the activity of an enzyme?
the more substrate there is the more chances of a collision with an active site meaning that the rate of reaction will increase, however, at one point the rate of reaction will stop increasing as every enzyme will be occupied so no matter how much substrate you add the rate will not increase
40
how does PH affect the activity of an enzyme?
If the PH is too high or too low the enzyme will denature and cause the shape of the active site to change which will lower the rate of reaction. Each enzyme will have an optimum PH where the denaturing does not occur so the rate will be at its highest
41
what two things can enzymes do to the substrate?
they can synthesize large molecules from small ones
or they can break down large molecules into smaller ones
42
what are 3 enzymes?
amylase
lipase
protease
43
what do carbohydrates break down into
sugars
44
what do proteins break down into
amino acids
45
what do lipids break into
fatty acids and glycerol
46
what test reagent do you use to test for starch?
iodine solution
47
what test reagent do you use to test for reducing sugars?
benedicts solution
48
what test reagent do you use to test for protein?
Biuret solution
49
what test reagent do you use to test for fat?
ethanol
50
what colour does iodine go if starch is present?
blue/black
51
what colour does iodine go if starch is not present?
yellow/orange
52
what colour does Benedict's solution go if reducing sugars are present?
green --> orange --> red (depending on how much sugar is present)
53
what colour does Benedict's solution go if reducing sugars are not present?
blue
54
what colour does the Buiret test go if protein is present?
pale purple/lilac
55
what colour does the Buiret test go if protein is not present?
pale blue
56
what happens to ethanol if fat is present
cloudy white emulsion
57
what happens to ethanol if fat is not present
clear
58
what chemicals are used in the biuret test
potassium hydroxide
copper sulfate
59
what are reducing sugars
reducing sugars cause a reducing reaction with the reagent. reducing sugars are sugars such as glucose, and fructose but not table sugar
60
what is a calorimeter used for
to calculate the energy in food
61
what are the steps to finding the energy of a food using a calorimeter?
1. measure the starting temperature of the water
2. measure the mass of the food
3. see the food alight, then place it under the test tube
4. measure the temperature at the end, and calculate the change in temperature
62
how much energy is needed to raise the temperature of a 1cm cube of water
4.2 joules
63
give 3 reasons why students' calorimeter will not be accurate
- taking too long to put the burning food under the test tube
-holding the foot at different distances away from the test tube which would affect how much energy is transferred into the air rather than the test tube
- not measuring the temperature of the water or the weight of the food accurately
- the food not burning completely
64
what are the 2 ways that dissolved substances move in and out of cells
diffusion
active transport
65
give an example of diffusion
moving oxygen into cells and removing carbon dioxide from cells
66
what happens in diffusion
molecules move from an area of high concentration to an area of low concentration through a partially permeable membrane
67
what is an example of active transport in plants?
root cells absorbing minerals from the soil.
68
what is an example of active transport in animals?
small intestines absorbing glucose from digested food
69
what happens in active transport
active transport is when molecules move from an area of low concentration to an area of low concentration, against the concentration gradient, which requires energy from respiration
70
what is the name given to the diffusion of water?
osmosis
71
what are the 2 types of cell division?
mitosis and meiosis
72
what types of cells does mitosis create?
create genetically identically diploid cells
73
how many cells does mitosis create?
2
74
what are the 6 stages of mitosis?
interphase
prophase
metaphase
anaphase
telophase
cytokinesis
75
what happens in interphase
interphase is a stage in a cell's life where the chromosomes are doubled
76
what happens in prophase
in this phase, the nuclear membrane breaks down and lets the chromosome into the cytokinesis
77
what happens in metaphase
in metaphase, the chromosomes line up along the centre of the cell and are connected to opposite sides of the cell wall by spindle fibres
78
what happens in anaphase
the chromosomes are pulled to opposite sides of the cell by spindle fibres
79
what happens in telophase
the spindle fibres disappear and new nucleus membranes start to form around the 2 sets of DNA.
80
what happens in cytokinesis
the cell pinches in the middle and separated into 2 separate cells
81
what stage is a cell in for most of the time?
interphase
82
what is mitosis used for
growth, repair and asexual reproduction
83
where does mitosis happen in plants?
in the shoots and roots
84
what happens to newly made plant cells at the roots and shoots
they elongate
85
how do plant cells elongate
by absorbing water into their vacuole by osmosis
86
what is growth
growth is a permanent increase in size.
87
what are baby percentile charts used for
to monitor if a baby is growing faster or slower than it is normal for their age
88
what does it mean if a baby is in the 65th percentile?
it means that 35 per cent of babies are above that weight and 65 per cent of babies have a mass lower than that weight
89
what are stem cells?
stem cells are cells that are blank and have the ability to differentiate into other cells
90
what are the 3 types of stem cells?
embryonic stem cells
adult stem cells
meristems
91
what is an embryonic stem cell?
cells that are taken from embryos at a very young stage
92
what are adult stem cells?
cells that are found inside our bones that can divide to repair or replace damaged cells
93
what are meristems
areas of the plants that rapidly grow. they can divide to make any type of plant cell
94
what are some uses of embryonic stem cells?
-replacing/repairing brain cells to treat Parkinson's
-replacing damaged cells in the retina of the eye to treat some kind of blindness
-growing new tissue for transplants and drug tests
95
what are some uses of adult stem cells?
- treatment of leukaemia
- potentially growing new tissues that are genetically matched to the patient
96
what are the 2 advantages of using embryonic stem cells?
- are easy to extract
- can produce any type of cell
97
give one disadvantage of using embryonic stem cells
embryo destroyed when cells are removed so some people believe have a right to live
98
what are the 2 advantages of adult stem cells?
- embryo destroyed so not an ethical issue
- if taken from the person to be treated will not cause the body to reject it
99
what is an advantage of using stem cells?
have the ability to replace faulty cells with a healthy cell
100
what is the risk of using stem cells?
the stem cells may not stop dividing and may cause a cancer
101
what are the 3 parts of the brain?
cerebral hemispheres
medulla oblongata
cerebellum
102
what is the purpose of the cerebral hemispheres?
control voluntary movement
interpret sensory information
responsible for learning and memory
103
what is the purpose of the medulla oblongata?
regulates the heart rate and breathing
104
what is the purpose of the cerebellum?
coordinates and controls precise and smooth movements
105
what are the 2 types of scans?
CT scan
PET scan
106
what does CT scan stand for
computerised tomography
107
what does PET scan stand for
positron emission tomography scan
108
how do CT scans work
- the patient is given a radioactive tracer which allows different parts of the brain to show up. Next many pictures of the brain are taken from lots of different angles, then the computer combines all of these images to give a 3-dimensional picture
109
how do PET scans work
the patient is given a small amount of radioactive glucose, which will travel to the parts of the body where respiration is happening very rapidly, and this shows up changes in parts of the body such as the brain that might indicate damage or disease. the scanner detects this radioactivity and you can see where the glucose is most concentrated.
110
why is it difficult to treat damage and disease in the brain and nervous system?
because they are well-protected
111
what are stimuli
a change in the environment
112
what are the 3 types of neurons?
sensory neurons
motor neurons
relay neurons
113
what is the function of a sensory neuron?
carry impulses to the CNS
114
what does CNS stand for
central nervous system
115
what is the function of the motor neuron?
carry impulses from the central nervous system to affect organs
116
what is the function of the Relay neurons?
Relay neurons are found only in the CNS
117
what will the nerve reaction be like when your finger touches a tree and you want to take your hand off it
the pain will be detected by the receptors which will send the electrical along the sensory neuron to the CNS where the relay neurons carry the signal to the motor neurons which will carry them to the effector muscles that will cause the hand to move
118
what part of a sensory neuron picks up the signal
dendrites
119
what part of a relay neuron passes the signal
axon endings
120
what are the 2 sides of a sensory neuron called?
dendron and axon
121
what is the fatty myelin sheath for
insulated the signal
122
what do you call the gap between 2 neurons?
synapses
123
Explain in 3 steps how an electrical signal crosses a synapse
1. electrical nerve impulse reaches the end of the axon
2. the electrical impulse causes chemical neurotransmitters to be released into the synapse
3. the neurotransmitters diffuse across the gap and fit into the receptors which will tell the other neuron what the electrical signal was so that a new electrical signal can be created on the other side
124
give 4 facts about the reflected arc
immediate
involuntary
innate
invariable
125
what is the point of a reflex arc?
they protect us from immediate harm because they create an immediate reaction which is much faster than a normal reaction which has to go all the way to the (more synapses) brain and be processed. this means that our body will be hurt for a shorter time
126
what do you call the hole in the eye where the light comes through
pupil
127
what 2 parts of the eye focus the light on the retail
cornea and lens
128
what are the receptors that are in the retina?
rods and cones
129
what do rods detect
black and white
130
what do cones detect
colour
131
what is the coloured part around the pupil?
iris
132
how does the image from the retina get to the nerve?
along the optic nerve
133
what are ligaments that are attached to the lens and control its shape?
suspensory ligaments
134
what muscles control how tight the suspensory ligaments are
ciliary muscles
135
what is the purpose of the iris?
it will make the size of the pupil bigger or smaller depending on how much light there is
136
what are 4 eye problems that could develop
cataracts
colour blindness
long sight
short sight
137
what is a cataract and how do they occur
cataracts occur when the lens becomes cloudy, which means that light cannot pass through the lens properly. which will cause the person to have blurred vision
138
what is colour blindness?
colour blindness occurs when one type of cone (red green blue) is missing or doesn't work properly.
139
what is long-sight
long-sighted people can focus on distant objects but not near ones. This
140
what is short sight?
when a person can focus on objects close to them but not distant ones
141
how can cataracts be fixed?
removing cloudy lenses and inserting an artificial lens
142
how can long-sight be fixed?
using a converging lens
143
how can short-sightedness be fixed?
using a diverging lens
144
what are the 2 types of reproductions?
sexual reproduction
asexual reproduction
145
explain sexual reproduction in 3 steps
gamete from mother fuses with a gamete from father
genetic information is mixed
offspring will have a different combination of genes so will have a variety of characteristics
146
what cell division does asexual reproduction use
meitosis
147
what is an advantage of sexual reproduction?
offspring will be genetically different which allows for variation and evolution. so if there is a change in the environment, some individuals will be more adapted and will survive
148
what is a disadvantage of sexual reproduction?
takes time and energy to find a mate
149
what are the 2 advantages of asexual reproduction?
only one parent - so they don't need to waste energy to find a mate which makes the reproductive cycle faster
offspring are identical to the parent which is good for organisms that are very well-adapted to an unchanging environment
150
what is a disadvantage of asexual reproduction?
there will be no variation so if the environment changes all will die
151
how many and what type of cells does meiosis create?
it will make 4 genetically different haploid daughter cells
152
where is DNA found?
DNA is the genetic material found in the chromosomes of the nuclei in cells that
153
what is inside of a chromosome
a string of genes
154
what is gene
a gene is a section of DNA that codes for a particular protein
155
what does a DNA look like
a long coiled molecule formed from two strands that twist together to form a double a helix
156
what joins the 2 strands of DNA
joined by bases
157
what are the 4 bases in DNA?
Adenine
thymine
guanine
cytosine
158
what are the complementary base pairs?
A-T
G-C
159
what holds the bases together in DNA
weak hydrogen bonds
160
describe the structure of DNA
DNA is a POLYMER made up of many MONOMERS called NUCLEOTIDES
161
what does a nucleotide consist of
Phosphate
deoxyribose sugar
base
weak hydrogen bond
162
explain the 3 steps to extract DNA from fruit
1. grinding the fruit with sand, using a pestle and mortar, to separate the cells
2. adding a detergent to break open the membranes
3. adding ice-cold Alcohol to cause the DNA to precipitate out
163
what are the 2 stages of protein synthesis?
transcription and translation
164
what is created in the transcription stage of protein synthesis
mRNA strand is created
165
where does the transcription stage of protein synthesis happen
in the nucleus
166
what happens in the transcription stage of protein synthesis in 3 steps
1. A section of DNA is unwound causing the 2 strands to separate
2. an enzyme (RNA polymerase) will bind to the noncoding DNA in the front of the Gene
3. The enzyme then used free complementary base pairs to construct a complementary DNA strand called the mRNA strand which is taken to the ribosome
167
what is the enzyme used in DNA synthesis?
RNA polymerase
168
what is the difference in mRNA to DNA
there is U base instead of T Base
169
where does the translation stage in protein synthesis happen
ribosomes
170
what happens in the translation phase of protein synthesis in 6 steps
1. the mRNA attaches to the ribosome, it will move along the mRNA strand reading one codon at a time
2. tRNA will bring amino acids to the ribosome, the amino acid will brought will depend on the order of bases on the tRNA
3. complementary bases on the tRNA bond with bases on the mRNA strand
4. the amino acids that are brought will join together to create a polypeptide amino acid chain
5. the tRNA then goes to collect another amino acid
6. each protein is formed from a specific number of amino acids that are in a particular order. The order of the bases in the DNA determines the order of the protein so each section of DNA codes for one particular protein
171
what is codon
3 bases that code for a specific amino acid
172
what is a polypeptide chain?
a chain of amino acids
173
who was the first person to discover the inheritance
Gregor Mendel
174
how did Mendel discover the inheritance?
He bred purebred tall peas and purebred short peas and realised that nearly all the offspring were tall which led him to discover that some traits were recessive while others were dominant. such as the dominant tall peas trait
175
what is gamete
a reproductive cell of a plant or animal that is haploid
176
what is zygote
the diploid cell that is created when 2 gametes are fused
177
what is an allele?
different forms of a gene that produce different variations of a characteristic
178
what does homozygous mean
having the same allele for a characteristic
179
what does heterozygous mean
having 2 different alleles for a characteristic
180
how do you show an allele is dominant?
by writing it in capital
181
what is a chromosome?
thin strands full of DNA
182
what is a genotype?
the alleles for a gene
183
what is the phenotype?
observable characteristics caused by the genotype
184
what are 2 diagrams used to show inheritance?
punnet square
genetic diagrams
185
what is the genotype of a male?
XY
186
what is the genotype of a female?
XX
187
what is the chance of having a male child?
50%
188
What are the 3 alleles for the blood group allele?
AOB
189
what are the 2 dominant blood group alleles?
A B
190
what is a recessive blood group allele?
O
191
what does co-dominant mean
when a heterozygous individual shows the effects of both alleles carried for the gene
192
name a sex-linked genetic disorder
Haemophilia
193
why are some genetic disorders more likely to be inherited by males?
this is because males have an XY chromosome while females have XX. Since males have only one X chromosome if a particular gene depends on an allele on the X chromosome, so for a recessive phenotype the genotype only needs to have one recessive allele as the Y chromosome will have no dominant allele to change it.
194
what are the 2 causes of variation?
genetic variation
environmental variation
195
how does a mutation happen
when the sequence of bases in a gene is changed
196
what can happen if a mutation happens in the non-coding section of the DNA?
could increase or decrease the ability of the RNA polymerase to bind to the DNA which could cause an increase or decrease in protein production
197
What was the Human Genome Project
a collaboration between scientists to decode the human genome (the order of bases on all human chromosomes).
198
When was the human genome project completed?
2003
199
what are the 3 advantages of the human genome project?
- can be used to alert people that they are at risk of certain diseases, and can therefore change their lifestyle early to reduce the chances of the disease developing
-distinguish between different forms of diseases such as leukaemia or Alzheimer's, as some forms of medicine are better for different forms of the disease
- can allow doctors to tailor treatments, as specific alleles might affect how a person responds to a treatment
200
what are the 2 disadvantages of the Human Genome Project?
- people who are at a higher risk of certain diseases might have to pay more to obtain life insurance
- it may not be helpful to tell someone they are at risk of a disease that has no cure
201
which 2 scientists discovered evolution
Wallace and Darwin
202
what is natural selection?
natural selection is where the environment (including the climate and other organisms) selects which individuals pass on their alleles to the next generation
203
give a ways the theory of evolution is important to modern biology
- it helps us understand relationships between different species and organisms
204
what is Darwin theory?
his theory suggests that young animals with advantageous variation that are better adapted to survive in their environment are more likely to survive and produce offspring that will have those same characteristics. while individuals that are not as well adapted will be less likely to survive and produce offspring
205
what were the 5 species of humans found in order?
Ardipithecus ramidus
Australopithecus aferensis
Homo Habilas
Homo Erectus
Home Sapiens
206
how did height change as humans evolved
we got taller
207
when did Ardi exist
4.4 million years ago
208
what species of human was Lucy
Australopithecus aferensis
209
how long ago did Lucy live
3.2 million years ago
210
how long ago did Homo
Habilas live
around 2 million years ago
211
how long ago did homo erectus live?
around 1.3 million years ag0
212
how did brain size change as humans evolved
it got larger
213
what were the 2 details of Ardipithecus ramidus?
- tree climber
- upright walker
214
what were the 2 details of Australopithecus aferensis?
- walked upright
- ape-like face
214
what were the 2 details of Homo Habilis?
- flat face
- used simple stone tools
215
what were the 2 details of Homo Erectus?
long distance walker
strongly built
216
what was a detain about homo sapiens?
used complex tools
217
what are the 2 ways to classify animals?
5 kingdom system
tree domain system
218
what are the 5 kingdoms?
Plants
Animals
Fungi
Protists
Prokaryotes
219
what are the 3 domains in the 3 domains naming system?
Eubacteria
Archaea
Eukaryota
220
what feature is in most animals
pentadactyl limb
221
what is selective breeding?
is when plants or animals with certain desirable characteristics are chosen to breed together. so that the offspring will also gain those favourable characteristics.
222
what are 5 factors that a person might want in their crops, which they use selective breeding in plant’s to acheive?
disease resistant
increased yield
better ability to cope with difficult conditions
faster growth
better flavour
223
give 2 benefits of selective breeding
has a low cost
future generations of plants/animals will maintain the characteristics
224
give 3 disadvantages of selective breeding
can lead to a lack of variety
there is no guarantee the characteristics will be passed on
the changes might harm the animal
225
what is genetic engineering?
the process of changing the DNA of an organism, often by introducing genes from another to genetically modified organisms
226
what are the 3 steps in genetic engineering
the gene for a characteristic can be cut out of a chromosome using an enzyme
the gene is then inserted inside the nucleus of a cell in a different organism
the cell will now produce the characteristics gained from the gene
227
give an example of genetic engineering
bacteria being modified to create human insulin-releasing bacteria
228
what are GM crops?
plants that have been genetically modified to give them new characteristics such as resistance to insect attacks and resistance to herbicides
229
what is tissue culture?
making many identical copies of a special organism. to create copies of GM species or to test out new drugs on the tissue
230
what are the advantages of using animal cell cultures?
can test the effect of drugs/chemicals without having to risk the life of an organism
can check for cancer cells in a sample from a patient
can produce important antibodies
231
what are the advantages of using plant cell cultures?
can produce thousands of identical plants from one parent plant
cells can be grown in culture to make plant products
can produce disease-free plants
can be grown in small spaces
232
what are the 4 stages of making human insulin?
1. DNA from a human cell is cut into pieces using restriction enzymes. These make staggered cuts across the double-stranded DNA. and will leave a few unpaired bases at each end called sticky ends
2. the same restriction enzyme will cut open the plasmid of the bacteria leaving matching sticky ends
3. the pieces of DNA containing the insulin gene are mixed up with the plasmids. the bases in the sticky end pairs will match up. a new enzyme called DNA ligase is added to link the plasmid back into a continuous circle
4. the plasmids are inserted back into bacteria. the bacteria can now be grown in a huge fermenter where they will continue to make human insulin
233
what are vectors
a vector is a name for anything that carries the new gene into a cell.
234
what are BT plants?
genetically modified plants that naturally produce the BT toxin which causes them to be insect repellent
235
what are the 2 advantages of BT plants?
crop damage is reduced so crop yield increases
less chemical insecticide is needed so harmless and useful insects are less likely to be harmed
236
what are the 3 disadvantages of BT plants?
seeds from BT plants are more expensive than normal seeds
insect pests may become resistant
BT gene might transfer to closely related wild plants by pollination, which would make those plants insect-repellent
237
what are 2 methods used to increase crop yield
fertilisers
biological control
238
what are the 3 advantages of fertilisers?
can help crops grow well
they increase crop yields
it is a good way to use animal waste
239
what do fertilisers have
nitrogen
potassium
phosphorus
240
what are the 3 disadvantages of fertilisers?
excess fertilisers can pollute waterways causing eutrophication
artificial fertilisers are expensive to make
can reduce soil diversity
241
what is eutrophication
excessive nutrients taken into lakes or rivers will cause algae to flourish causing the environment to be damaged
242
what is biological control?
introducing a natural predator, parasite or disease of the pest to the environment to keep the population low
243
what are the 3 advantages of biological control?
the pest cannot become resistant
if well chosen the control agent is specific to the pest
avoids using chemical pesticides which can leave harmful residue and kill useful organisms
244
what are the 2 disadvantages of biological control?
does not get rid of the organism completely
the control agent may become the pest itself
245
what is health
a state of complete physical mental and social wellbeing
246
what is physical health?
sleeping, eating and being free from diseases
247
what is mental well-being?
how you feel about yourself
248
what is social well-being?
how you get on with other people
249
what are the 2 types of diseases?
communicable
non-communicable
250
what is a communicable disease?
a disease that can be passed from one person to another
251
what is a communicable disease?
a disease that cannot be spread from one person to another
252
what is a pathogen?
an organism that causes an infectious disease
253
what are the 2 features of communicable diseases?
- rapid variation in the number of cases
- cases can be localises
254
what are 2 features of non-communicable diseases?
number of cases changes gradually over
cases may be more widely spread
255
what are 3 examples of communicable diseases?
malaria, typhoid, cholera
256
what are 3 examples of non-communicable diseases?
cancer,
diabetes
heart disease
257
what are the 4 types of pathogens?
bacterium
virus
fungi
protist
258
how does bacterium make us feel ill?
bacteria may release toxins that make us feel ill. some bacteria invade and destroy body cells
259
how do viruses make us feel ill?
virus stake over a body cell to make toxins or make more viruses
260
what are fungi
fungi are eukaryotic organisms
261
what are protists
protists are eukaryotic organisms, many are free-living but some are pathogens
262
what are 3 diseases that are caused by the bacterium?
cholera
tuberculosis
stomach ulcers
263
what is a disease that is caused by protists
malaria
264
what are 2 diseases that are caused by viruses?
HIV/aids
Ebola
265
what is a disease caused by fungus?
ash die back (Chalara)
266
what is a symptom of cholera?
watery, pale-coloured diarrhoea
267
what are 2 symptoms of malaria?
fever
weakness
chills
sweating
268
what are 2 symptoms of HIV/AIDS?
mild flu-like symptoms
repeated infections
269
what are 2 symptoms of tuberculosis?
lung damage
blood speckled mucus
weight loss
fever
nigh sweats
270
what are 2 symptoms of Ebola?
internal bleeding
fever
severe headache
muscle pain
vomiting
diarrhoea
271
what are 2 symptoms of stomach ulcers?
inflammation in the stomach causing pain
bleeding in stomach
272
what are 2 symptoms of chalara?
leaf loss
bark lesions
dieback of top of tree
273
what is the vector for malaria
mosquito
274
how is malaria spread
the mosquito that carries protist bites a human and injects the protist
this infects the liver cells which causes the blood cells to become infected
when another mosquito bites that sma e person and takes a blood meal it will also carry the protist
275
what happens in HIV
HIV virus enters the blood and reproduces inside the white blood cells causing the white blood cells to be destroyed. After a while so many white blood cells will be damaged that the immune system cannot work properly
276
what is a way of reducing the spread of cholera?
boil water
wash hands thoroughly after using the toilet
277
what is a way to reduce tuberculosis?
ventilate buildings to reduce the chance of beating in bacteria
diagnose infected people quickly and give them antibiotics
isolated infected people so they cannot spread the infection
278
what is a way to reduce malaria?
prevent mosquito bites by removing water
use mosquito nets when sleeping
279
what are some ways to reduce ebola?
isolate infected people
wear fully protected clothing when working with infected people or dead bodies
280
what does STI stand for
sexually transmitted diseases
281
what are the 2 virus lifecycles?
lytic and lysogenic
282
what is the difference between the lytic and lysogenic lifecycles of a virus?
in the lysogenic cycle, the virus will stay dormant inside the DNA of the cell and let the cell duplicate by mitosis before destroying the host cell
283
what are the 4 steps in the life cycle of a virus?
1. The virus attaches to the host cell
2. the virus injects its DNA into the DNA of the cell
3. Virus BNA copies itself and creates virus proteins to be made using the host cell's organelles
4. the virus DNA and virus proteins are packaged together to create new viruses that are released from the host cell, which usually destroy the host cell
284
what are the 3 common methods of HIV transmission?
- unprotected sex with an infected partner
- sharing needles with an infected person
- transmission from infected mother to foetus
- infection from blood products
285
what are 3 ways to reduce the spread of STIs
- using condoms during sexual intercourse
- screening people, including a pregnant woman
- screening blood transfusion
- supplying sterile needles to drug abusers
- treating infected people using antibiotics
286
what are the 2 types of human defences?
chemical and physical
287
what is the point of physical barriers in the body?
make it hard for pathogens to enter the body
288
what is the point of chemical defences in the body?
chemicals produced to kill or make pathogens inactive
289
what are 2 physical barriers in the body?
unbroken skin forms a protective barrier because it is too thick for most pathogens to get through
sticky mucus in the breathing passages and lungs trap pathogens and the cilia lining the lungs move in a wave motion out of the lungs
290
what are 3 chemical defences? in the body
lysozyme enzymes in tears kill bacteria by digesting their cell walls
lysozyme enzyme is also present in saliva and mucus
hydrochloric acid in the stomach kills pathogens in food and drink
291
what is the purpose of the immune system?
helps protect the body from attacking pathogens.
292
how does the immune system deal with viruses in four steps?
1. when the body recognises it is under attack it will release non-specific phagocytes.
2. The body will now activate a lymphocyte that has matching antibodies to the unique antigens on the virus. If your body has not encountered this infection before it will mutate lymphocytes until a lymphocyte that fits the antibody is created
2. the lymphocytes will finish the infection and leave some of the antibodies in the bloodstream so if infected again the body will know which lymphocytes to use
293
how do phagocytes fight infections?
they are non-specific so they can deal with any infection. They will engulf the pathogen and the enzymes inside will destroy the pathogen. However, since they can only deal with one pathogen at a time they are too slow to deal with the entire infection so instead are used to deal with the pathogens until the lymphocytes arrive
294
how lymphocytes work
lymphocytes have the ability to create unique antibodies that can destroy pathogens. once a correct antibody is identified the lymphocyte will create thousands of antibodies that can lead to thousands of pathogens
295
what are memory lymphocytes?
lymphocytes that stay in the blood in case a secondary infection occurs
296
what is immunisation
when you give a person a vaccine to prevent them from becoming ill from a disease
297
how do vaccines work
a vaccine will contain antigens from the pathogens (often in a weak or dead state). the person's lymphocyte will produce antibodies against the antibody, and some of the lymphocytes will stay in the body so if the person is actually infected the memory lymphocytes will produce a very rapid secondary response.
298
what are the 3 advantages of immunisation?
immunity iid produced without being ill
immunity lasts a long time, often for life
if most people are immune then the people who are not vaccinated are also less likely to catch the disease (herd immunity)
299
what are the 2 disadvantages of immunisation?
some people get mild reactions to the disease
very rarely a person can have a major harmful reaction
300
what is the purpose of antibiotics?
to treat bacterial infections
301
how do antibiotics kill bacteria?
antibiotics inhibit cell processes. for example, some antibiotics stop the bacterial cell walls from forming
302
how do you compare the effects on bacteria?
place desired antibiotics on bacterial culture in a Petri dish. then leave the antibiotics to get to work and then measure the radius of the clear zones around each antibiotic and calculate the area of the clear zone
303
what is the purpose of using an aseptic technique?
to prevent contamination of cultures from microorganisms in the air when they are being prepared
304
what are the 3 steps to aseptic technique?
1. sterilising dishes and culture media
2. sterilising inoculating loops
3. sealing petri dished
305
what are 2 ways that petri dishes can be sterilised?
using autoclaves
heating to a high temperature
306
how to sterilise culture media
heating to high temperatures
307
what is the purpose of an inoculating loop?
used to transfer microorganisms to the growth medium
308
how do you sterilise inoculating loops?
heating it in a hot flame then cooling
309
why do you not completely seal petri dishes?
to prevent the growth of anaerobic bacteria
310
why are cultures at school only incubated to 25'c
any higher and it will encourage rapid growth in bacteria
311
what are medicines
chemicals that are used to treat illness
312
what are the 4 stages of testing a new medicine?
discovery
preclinical testing
clinical trials 1
clinical trials 2
313
what happens in the preclinical stage of testing
the medicine is tested on cell cultures, tissue cultures and animals to show that the medicine can get into cells without harming them and can damage pathogens inside
314
what happens in stage 1 clinical trials when testing new medicines
a healthy volunteer is given a very small dose of the drug to make sure the drug is not toxic
315
what happens in stage 2 clinical trials when testing new medicines
the medicine is tested on a person with the disease to test its efficiency and how to find the optimum dose
316
what are monoclonal antibodies?
are antibodies that carry useful chemical marker
317
give 3 uses of monoclonal antibodies
used in pregnancy tests
used diagnose diseases
in the treatment of diseases
318
how are monoclonal antibodies used in pregnancy tests?
the monoclonal antibody can identify if the pregnancy hormone is present in the urine, the monoclonal antibodies can match the hormone and cause a reaction with the indicator
319
how are monoclonal antibodies used in the diagnosis of diseases?
monoclonal antibodies can stick to blood clots or cancer cells so they can be detected
320
how are monoclonal antibodies used in the treatment of diseases?
the way monoclonal antibodies target specific cells can be used to target treatment
321
what is a non-communicable disease?
a disease that cannot be passed on by a pathogen
322
what are 5 factors that affect the risk of developing a non-communicable disease?
genes
age
sex
environmental
lifestyle factors
323
how do genes affect the risk of getting a non-communicable disease?
different alleles of a gene may be more prone to a particular disease, these genes have the chance to be passed on to children
324
how does age affect the risk of getting a non-communicable disease?
the older the body the more likely that cells may develop mutations
325
how does sex affect the risk of getting a non-communicable disease?
the female hormone oestrogen has protective effects that men don't get
326
give 2 examples of how the environment affects the risk of getting a non-communicable disease.
factors such as air pollution can cause lung disease
poisons in food and drink can damage the body
327
give 4 examples of how lifestyle affects the risk of getting a non-communicable disease.
The way we live, including diet, alcohol, smoking and exercise
328
what are the 4 factors that make smoking dangerous
- nicotine is addicting
- carbon monoxide in fumes reduces how much blood the oxygen can carry
- the chemicals in tar can cause cancer
- substance in the cigarette can cause blood vessels to narrow and lead to cardiovascular disease
329
how is alcohol dangerous?
alcohol contains ethanol which is poisonous to cells when absorbed from the gut and since it will travel through the liver the liver cells are likely to be damaged reading to liver disease
330
what do you call it when someone does not eat enough?
malnutrition
331
what does too much body fat lead to
obesity
332
what are 2 methods used to measure obesity?
BMI
waist: hip ratio
333
what is the formula for waist: hip ratio
waist measurement/hip measurement
334
what is the equation for BMI?
weight/height squared
335
how high does your BMI need to be to be considered obese?
above 30 in adults
336
what is the link between waist-to-hip ratio and CHD?
the higher your waist-to-hip ratio the more risk at risk you are for CHD
337
what 4 lifestyle changes you could do to reduce the chance of Cardiovascular disease
give up smoking
take more exercise
east a healthier diet (lower fat, sugar and slats)
lose weight
338
what is an example of a medication that reduces the risk of Cardiovascular disease?
beta-blockers that reduce blood pressure
339
what is an example of surgery that can be used to help people with cardiovascular disease?
a stent
heart bypass
340
what is a stent and why is it used
if an artery becomes lowered the blood flow will lower which could cause damage to the tissue that relies on getting ion blood from the artery, so a wireframe mesh called a stent is inserted into the narrow part of the artery to lift it up, the artery is usually pushed up by a balloon to make the stent fit before being removed
341
what happens in a heart bypass
a surgery where a new artificial vein is inserted to bypass the blocked coronary artery
342
what are the positives of changing your lifestyle to prevent cardiovascular disease?
no side effects
may reduce chances of getting other health conditions
cheapest option
343
what are the negatives of changing your lifestyle to prevent cardiovascular disease?
may take time to work or may not be effective
344
what are the positives of using medicine to prevent cardiovascular disease?
will start working immediately
easy to do
cheaper and less risky than surgery
345
what are the negatives of using medicine to prevent cardiovascular disease?
need to be taken long-term and can have side effects
may not work well with other medications the person is taking
346
what are the positives of using surgery to prevent cardiovascular disease?
usually a long-term solution
347
what are the negatives of using surgery to prevent cardiovascular disease?
there is a risk that the person will not recover after the operation
surgery is expensive
more difficult to do than giving medication
there is a risk of the person developing an infection after surgery
348
what are pests
an organism that causes damage to a crop plant, e.g plant-eating insects
349
what are some physical defences in plants?
bark
thich waxy cuticle (outer covering of a leaf)
spikes and thorns
cellulose cell walls
350
what are some chemical defences in plants?
poisons in their cells to deter pests
chemicals that kill pathogen
351
what are some uses of chemicals that are found in plants and used as medicines?
- to treat malaria
- to treat heart disease
- to relieve symptoms eg pain or fever
352
where is aspirin from
the willow tree
353
what are 3 ways to detect and identify plant disease?
visible symptoms
distribution analysis
laboratory testing
354
what are the first signs of plant disease?
visible symptoms
355
what are some visible symptoms of plant disease?
- change in normal appearance (for example a different colour of flowers/leaves)
- overgrowth in parts of the plant (swelling on roots)
- death of parts of the plant
- underdevelopment of parts of plants
356
what is distribution analysis?
looking at the way plants are distributed in the environment to help identify possible causes of disease
357
what are the 4 factors to take into analysis when using distribution analysis?
How many plants are affected
Where are diseased plants found
What species of plant is affected
Do the symptoms change over time
358
what is laboratory testing (plant diseases)
scientist using different techniques to identify the disease in a laboratory
359
what are 4 tests used in laboratory testing (plant diseases)
microscopic examination of plant material for signs of pathogen
using antibodies to test for the presence of a pathogen
using genetic testing to identify any pathogen found
soils sample testing to rule out soil factors such as nutrient deficiency
