Y10 MOCKS 1 Flashcards
AQA Biology GCSE 2024 (328 cards)
1
Q
What is a eukaryotic cell?
A
A cell which has a nucleus
2
Q
What is a prokaryotic cell?
A
a cell which doesn’t have a nucleus
3
Q
what is an example of a eukaryotic cell?
A
animal or plant cell
4
Q
what is an example of a prokaryotic cell?
A
a bacterial cell
5
Q
what is the function of a red blood cell?
A
to carry oxygen
6
Q
what is the function of a guard cell?
A
allows gases to enter and leave the cell
7
Q
what is the function of a root hair cell?
A
to absorb water and nutrients
8
Q
what is the function of a sperm cell?
A
to fertilise an egg cell
9
Q
what is the function of a nerve cell?
A
to carry electrical impulses
10
Q
what is the function of a skin cell?
A
covers the body
11
Q
what is the function of a palisade cell?
A
has lots of chloroplasts so it absorbs more light to increase the rate of photosynthesis
12
Q
what is the function of an epithelial cell?
A
produces mucus
13
Q
what is a cell?
A
the building block of living things
14
Q
what is a tissue?
A
a group of cells with a similiar structure and function
15
Q
what is an organ?
A
a collection of tissues working together to perform a function (e.g stomach)
16
Q
what is an organ system?
A
a collection of organs working together to perform a function (e.g digestive system)
17
Q
what is the function of the cell wall?
A
made of cellulose and strengthens the cell
18
Q
what is the function of the mitochondria?
A
releases energy via respiration
19
Q
what is the function of the vacuole?
A
filled with cell sap and keeps the cell rigid
20
Q
what is the function of the chloroplasts?
A
contains chlorophyll to absorb light for photosynthesis
21
Q
what is the function of the cytoplasm?
A
chemical reactions take place here
22
Q
what is the function of the nucleus?
A
controls the cell and contains DNA
23
Q
what is the function of the ribosomes?
A
a site of protein synthesis
24
Q
what is the function of the cell membrane?
A
controls entry and exit of substances into the cell
25
what is the function of the epithelial tissue in the stomach?
protects the stomach by covering the inner and outer part of it
26
what is the function of muscle tissue in the stomach?
contracts for movement which churns the food
27
what is the function of glandular tissue in the stomach?
produces acid and enzymes
28
how has a sperm cell adapted?
has a tail to swim
has many mitochondria
head contains DNA and digestive enzymes
29
how has a nerve cell adapted?
long, thin fibres
30
how has a muscle cell adapted?
many mitochondria for energy
31
what are the 2 types of microscope?
electron and light
32
what are the advantages of a light microscope?
can study live specimens
cheap
portable
can see colour
33
what are the disadvantages of a light microscope?
lower resolution and magnification
34
what are the advantages of an electron microscope?
higher resolution and magnification
can see 3D images (cellular structures)
35
what are the disadvantages of an electron microscope?
expensive
don't see colour
only work in a vacuum
bulky
affected by magnetic fields
36
what is the formula to calculate the magnification of a cell?
image size = magnification x actual size
37
what is mitosis needed for?
growth and repair
38
what is differentiation?
when cells become specialised to perform a function
39
what are stem cells?
unspecialised cells which can differentiate into different types of cells
40
where can stem cells be derived from in humans?
embryos or adult bone marrow
41
why are scientists experimenting with stem cells?
medical treatments and research
41
why are scientists experimenting with stem cells?
medical treatments and research
42
what is diffusion?
the movement of particles/dissolved substances from a high concentration to a low concentration down a concentration gradient until an equilibrium is reached. It is a passive process
43
what is osmosis?
the net movement of water from an area of high concentration to an an area of low water concentration across a semi-permeable membrane. It is a passive process
44
what is active transport?
the movement of particles/dissolved substances from an area of low concentration to an area of high concentration against the concentration gradient. It requires energy
45
what is the function of the mouth?
teeth and enzymes in saliva break down food
46
what is the function of the salivary gland?
produces saliva which contains enzymes
47
what is the function of the oesophagus?
transports food from mouth to stomach
48
what is the function of the stomach?
produces hydrochloric acid, food is broken down with enzymes
49
what is the function of the liver?
produces bile which neutralises the stomach acids so the enzymes don’t denature and it emulsifies fats
50
what is the function of the pancreas?
produces enzymes to break down food
51
what is the function of the gall bladder?
stores bile then releases it into the small intestine
52
what is the function of the small intestine?
it produces enzymes which break down food. the products are then absorbed into the blood
53
what is the function of the large intestine?
water is absorbed
54
what is the function of the rectum?
stores faeces
55
what is the function of the anus?
releases faeces
56
which order does food travel through the digestive system?
mouth -> oesophagus -> stomach -> small intestine -> large intestine -> rectum -> anus
57
what parts of the body are made of proteins?
enzymes, antibodies, hormones
58
what is a catalyst?
something that speeds up a chemical reaction without being used up
59
what is an enzyme?
a biological catalyst
60
what happens to enzymes at a high pH or temperature?
they denature, so the substrate no longer fits into the active site
61
what organs secrete amylase?
salivary gland
pancreas
small intestine
62
what organs are amylase secreted into?
mouth
small intestine
63
what does amylase do?
breaks down with starch to produce sugar
64
what organs secrete protease?
stomach
pancreas
small intestine
65
what organs is protease secreted into?
stomach
small intestine
66
what does protease do?
reacts with proteins to produce amino acids
67
what organs secrete lipase?
pancreas
small intestine
68
what organs is lipase secreted into?
small intestine
69
what does lipase do?
reacts with lipids to produce fatty acids and glycerol
70
where is hydrochloric acid secreted from?
the stomach
71
where is hydrochloric acid secreted into?
the stomach
72
where is bile made?
the liver
73
where is bile stored?
the gall bladder
74
where is bile secreted into?
the small intestine
75
what are the functions of hydrochloric acid?
to provide the best conditions for stomach enzymes
kills bacteria
76
what are the functions of bile?
neutralises stomach acid
enzymes in small intestine work best in alkaline conditions
emulsifies fats
77
what is the test for protein?
biurets reagent
blue -> purple
78
what is the test for starch?
iodine
orange/brown -> blue/black
79
what is the test for sugar?
benedict's reagent + heat
blue -> red
80
how does temperature increase transpiration?
high temperature -> increased evaporation of water from leaf surface
81
how does humidity increase transpiration?
low humidity -> greater concentration gradient -> more water can evaporate
82
how does wind increase transpiration?
more wind -> greater air flow -> more water can evaporate from the leaf surface
83
how does light intensity increase transpiration?
higher light intensity -> stomata remain open to allow c02 to enter plant for photosynthesis -> more water can leave via the stomata
84
what are the adaptations of a root hair cell?
large SA
many mitochondria
85
# Xylem's structure
what are the adaptations of the xylem?
hollow tubes made of lignin
86
what are the adaptations of the phloem?
tubes of elongated cells
cell sap in the phloem moves from one cell to the next as there are pores in the end walls
87
what is the function of the meristem?
contains stem cells which can differentiate into other cell types
88
what is the function of the palisade mesophyll?
absorbs light for photosynthesis
89
what is the function of the spongy mesophyll?
gaps between cells allow gases to pass through easiliy
90
what is the function of the stomata/guard cells?
opens and closes by changing size to allow gases to enter and exit
controls transpiration
91
what is the function of the xylem?
transports water and ions
92
what is the function of the phloem?
transports sugars (translocation)
93
what are the types of pathogens?
bacteria
virus
protist
fungus
94
how do (bacterial) pathogens make us feel ill?
they produce toxins which damage our tissues and make us feel ill
95
how do viruses destroy cells?
viruses reproduce in cells which causes them to burst open/ causes cell damage
96
how does a vaccination make someone immune to a pathogen?
introduces small quantities of dead/inactive forms of a pathogen into the body
this stimulate the white blood cells to produce antibodies
this means that if the same pathogen re-enters the body, antibodies can be produced rapidly
97
how does the trachea/ bronchi defend against disease?
cilia (hairs) waft the mucus to the back of the throat where it is swallowed and goes to the stomach
98
how does the stomach defend against disease?
strong acids in the stomach (pH 2) kill most bacteria
99
how does the nose defend against disease?
nose hair traps pathogens
snot/mucus can trap pathogens
100
how does the skin defend against disease?
a layer of dead cells full of keratin acts as a physical barrier
produces antibacterial fluids
101
what is the first line of defence against disease?
your body's natural barriers to infection
non-specific
102
what is the second line of defence?
phagocytosis (a type of white blood cell)
non-specific
6 billion per litre
103
describe phagoytosis?
phagocytes are attracted to pathogens when they have been 'branded' by antibodies
when a phagocyte comes into contact with a pathogen, it binds to it
the membrane of the phagocyte surrounds the pathogen, breaks it down with digestive enzymes and engulfs it into its vacuole
104
what is the third line of defence?
lymphocytes (a type of white blood cell)
specific
3 million per litre
105
how do lymphocytes defend against disease?
recognises one type of antigen and binds to it
lots of antibodies are produced which clump the pathogens together
this prevents them from entering cells and make them more vulnerable to phagocytosis
antibodies can also cause cell lysis
lymphocytes also produce antitoxins, which neutralise any toxins produced by the pathogen
memory lymphocytes are also made, which circulate the blood and provide long-term immunity
106
why does each lymphocyte have a specific antibody to attack a specific pathoogen?
each lymphocyte only produces one types of antibody. the binding site has a unique shape that will only match one type of antigen
107
what type of pathogen causes smallpox?
a virus
108
how was james phipps given immunity to smallpox?
he was infected with cowpox by edward jenner, which produced memory cells for it. the antibodies needed for smallpox and cowpox were similar, so his body could quickly find the antibodies needed for smallpox as well.
109
what happens if memory cells recognise an antigen?
they multiply to quickly destroy the pathogens. the antibody concentration stays high in case of another infection
110
how does ring vaccination work?
you only vaccinate people who have been in contact with the infected person
used if the virus mutates quickly or if there aren't many vaccines
111
define monoclonal?
all one type
identical copies of one type of antibody
112
how is a hybridoma cell made?
b-lymphocytes from a mouse (specific)
+
tumour cells ( can divide)
I
membranes broken down with detergents or electricity
I
> hybridoma cell (MAKES specific antibodies + can divide)
monoclonal antibodies are then purified
113
name the main uses of monoclonal antibodies?
pregnancy/covid tests
locating/ identifying specific molecules by binding to them with fluorescent dye
diagnosing cancer
detecting pathogens/ measuring hormone levels
114
pros of monoclonal antibodies?
cancer: only combine with tumour cells, so healthy body cells wouldn't be killed
they can also encourage your immune system to directly attack the cancerous cells
can be produced quickly
115
cons of monoclonal antibodies?
can produce immune responses from the foreign mous proteins
has lots of side effects like chills, fever, nausea and blood pressure changes
ethical issues
have previously resulted in a cytokine storm (organ failure)
116
what is the first clinical phase of drug trials?
small number of healthy male volunteers
testing for safety in humans
10-100
117
what is the second clinical phase of drug trials?
small number of infected patients
testing for effectivity, safety, dosage
100-400
118
what is the third clinical phase of drug trials?
large scale
3000+ volunteers
does it work for everyone?
testing for dosage and safety
uses placebo
119
what is the fourth clinical phase of drug trials?
rollout
takes over a decade
costs around half a billion pounds
120
why are drug trials peer-reviewed?
opposing companies are the most critical of their competitors
121
what is a preclinical drug trial?
tested on cells then genetically engineered mice
122
how does antibiotic resistance happen?
through mutation:
there are errors when the bacteria copies its DNA
some of these random mutations give the bacteria antibiotic resistance
the resistant bacteria survive and reproduce, increasing the resistant strain.
if antibiotic courses aren't finished:
the most dangerous bacteria are left at the end, as the weakest bacteria are killed first
this means that any surviving resistant bacteria had loads of space to reproduce
123
what family does MRSA belong to?
staphylococcus
124
what do antibiotics do?
interfere with a pathogen's metabolism
slow bacterial growth and reproduction long enough for the immune system to help
125
why is the heart referred to as a double circulatory system?
on one circuit of the body, the blood passes through the heart twice
126
how does the blood on the left side of the heart differ to the blood on the right side?
the blood on the left is oxygenated and higher pressure
127
what tissue makes up the heart?
muscle
128
what is the role of the coronary artery?
supplies oxygen and sugars to the heart
129
why is the left ventricle the biggest chamber?
it needs to have lots of strong muscle to pump blood all through the body, so the chamber is bigger and the muscle around it is thicker, so can contract more powerfully
130
what is the journey of the blood in the circulatory system?
lungs -> pulmonary vein -> left atrium ->ATRIO-VENTRICULAR VALVE-> left ventricle ->SEMI-LUNAR VALVE-> aorta -> rest of the body -> vena cava -> right atrium -> ATRIO-VENTRICULAR VALVE-> right ventricle ->SEMI-LUNAR VALVE -> pulmonary artery -> lungs
131
how does the blood travel?
the part containing the blood contracts and the one in front realxes, sending the blood forwards. then, the one in front contracts and the one in front relaxes and so on
132
describe the stages of the cardiac cycle?
the atriums(atria) relax and the blood flows in
the ventricles relax and the atria contract, so blood is squeezed into the ventricles
the ventricles contract, the valves shut and the blood is squeezed out of the heart through the arteries
133
what are the advantages of an artificial heart?
less likely to be rejected by the immune system
easier to get
134
what are the disadvantages of an artificial heart?
usually temporary fix (5 years)
surgery can lead to bleeding or infection
electrical motor could fail
could cause blood clots and strokes
135
what are the advantages of a heart transplant?
leads to better quality of life
permanent fix
136
what are the disadvantages of a heart transplant?
major surgery
anti-rejection drugs needed
long recovery time
few donors available
immune system could rejects it
137
what controls the resting heart rate?
a group of cells called pacemakers which send electrical signals to the heart muscle
this can be replaced by an artificial pacemaker
138
what would happen if a coronary artery got blocked?
less blood flow
=
less glucose and oxygen would reach the heart
=
heart has less energy
=
heart can't contract
=
cells may die
=
heart attack
139
what is the name for fatty deposits of cholestrol?
atheroma
140
what are the consequences of cholestrol being stuck in the lining of the coronary artery?
smaller vessel diameter
vessel could rupture
blood clots could form
141
what is the name for a blood blockage?
thrombosis
142
what can narrowing of the coronary artery cause other than a heart attack?
angina:
attacks of chest pain caused by reduced blood flow
cardiac arrest:
when the heart stops pumping blood to vital organs
143
what are the risk factors for heart disease?
genetic factors
diet (salt and saturated fat)
lack of exercise
high blood pressure
144
what are statins?
drugs that stop the liver producing cholestrol
145
what are the properties of an artery?
out of the heart
oxygenated blood
>EXCEPT PULMONARY ARTERY
low c02 content
low blood pressure
fast flow
strong pulse
thick wall
no valves
small lumen diameter
146
what are the properties of a vein?
into the heart
deoxygenated blood
>EXCEPT PULMONARY VEIN
high c02 content
high blood pressure
slow flow
no pulse
thin wall
valves
very large lumen diameter
147
what is a capillary?
a type of very thin blood vessel
they are found everywhere
c02, general waste products and water pass into the capillaries
>VIA DIFFUSION
148
what is a capillary?
very thin type of blood vessel
found everywhere
c02, general waste and water pass into the capillaries via diffusion
149
how are capillaries adapted to their function?
thinner cell walls (one cell thick)
thick lumen so more substances can pass through the capillary
150
what is the whole blood split into?
blood cells 45%
plasma 55%
151
what is in plasma?
water 90%
dissolve solutes 10%
152
what is in the dissolved solutes of plasma?
proteins
> antibodies, clotting factors, LDLs, HDLs
hormones
digestion products
> glucose, glycerol, amino acids
minerals
waste products
> urea, carbon dioxide, lactic acid
153
what is in the blood cells part of the whole blood?
white blood cells 25%
> immune system
red blood cells 70%
> carry oxygen
platelets 5%
> clotting stream
154
what do the white blood cells consist of?
phagoctes 75%
>engulf and digest bacteria
lymphocytes
>antibodies and memory cells
155
what are the adaptations of a red blood cell?
biconcave shape
> larger SA:V ratio
> faster diffusion
no nucleus
> carry more haemoglobin which binds tightly to oxygen
156
what is haemoglobin?
a protein without oxygen bound to it (dark red)
oxyhaemoglobin is the same protein but with oxygen bound to it (bright red)
it is found in all arteries except the pulmonary artery. iron is found at the centre of the protein, which binds the oxygen
iron is needed to make haemoglobin
157
how is oxyhaemoglobin formed?
in the lungs, haemoglobin binds with oxygen
oxyhaemoglobin is now formed and the blood is now bright red
the blood carries the oxygen to all the tissue
the haemoglobin releases oxygen and the blood is now dark red
haemoglobin is now formed and oxygen diffuses into the cells
blood returns to the lungs
158
what is blood clotting?
a series of chemical reactions resulting in the change of fibrinogen ( a soluble blood protein) to fibrin ( a soluble blood protein)
this forms a network of fibres which trap blood cells and cause a clot. the clot then hardens to form a scab
159
what are platelets?
small fragments of cells involved in blood clotting
160
what does anerobic mean?
without oxygen
161
what does aerobic mean?
with oxygen
162
what is respiration?
breaking down glucose to provide energy for the cell
it is an exothermic reaction which is continuously occurring in living cells
a biochemical reaction
163
what is fatigue?
when muscles accumulate lactic acid and can't contract effectively
164
what is glycogen?
a polymer of glucose used as an energy store
165
what is oxygen debt?
the oxygen needed to break down lactic acid
166
what is the equation for aerobic respiration/ photosynthesis?
glucose + oxygen -> carbon dioxide + water
c6h12o2 + 6h2o -> 6co2 + 6h2o
167
what is the equation for anerobic respiration in muscles?
glucose -> lactic acid
168
why does anerobic respiration result in less energy?
the oxidation of glucose is incomplete, so much less energy is transferred
169
what is the equation for anerobic respiration in plant and yeast cells?
glucose -> ethanol + carbon dioxide + energy
C6H12O6 ⟶ 2C2H5OH + 2CO2
this is called fermentation in yeast cells and is used to make alcoholic drinks and bread
170
why do mitochondria have folded inner membranes?
for a larger SA
171
where are the most mitochondria found?
muscle cells - needed for contraction
nerve cells - needed to produce impulses
172
which cells have few mitochondria?
prokaryotic cells and dead cells
173
what effect does exercise have on pulse rate?
during exercise, the muscles need energy to contract
this energy comes from glucose and oxygen to produce co2
more glucose and oxygen are needed, so the pulse rate increases, meaning the blood is pumped round to the muscles faster, so glucose and oxygen arrive faster and waste products get removed faster
174
what are the stages of anerobic respiration?
heart and lungs can't supply oxygen fast enough
aerobic respiration provides less and less energy
SO
anerobic respiration provides energy
glucose is broken down into lactic acid
lactic acid accumulates in muscles, causing fatigue
FORCED TO STOP EXERCISE
some lactic acid is oxidised to water and oxygen
some lactic acid is transported from muscles to liver
oxygen debt has been repayed
175
which type of respiration is the most complete breakdown of glucose?
aerobic respiration (19x as effective)
176
what does 'repaying the oxygen debt' mean?
oxidising the lactic acid to oxygen and water
177
how does your fitness affect the changes in breathing rate when exercising?
unfit:
- breathing rate increases faster due to the
smaller lung volume
slower diffusion
slower blood flow
fit:
-lower resting breathing rate as each breath transfers more oxygen to the blood
repays the oxygen debt faster
returns to normal faster
higher max breathing rate
178
what is glycogen?
a polymer of glucose
it is made of stored glucose molecules, when the body has too much glucose, as it is stored until the body is short on glucose
it is broken down by glucagon into glucose which is released into the blood. glycogen formations is promoted by insulin
it is found in the liver
179
what is metabolism?
the sum of all the chemical reactions that take place in the body
180
what is a catabolic reaction?
this break down large molecules into smaller ones and don’t require much energy from respiration
these are exergonic and give out energy
eg. amino acids broken down into urea
181
what is an anabolic reaction?
a synthesis reaction where larger, complex molecules are formed
they require much more energy released from respiration and are endergonic
eg. photosynthesis; glucose -> starch
182
what are triglycerides?
made from a glycerol molecules and three fatty acid molecules
required to synthesise lipids
183
what is required to convert glucose into amino acids in plants?
glucose is joined with nitrates from the soil to form amino acids
184
what is the formula for cardiac output?
heart rate x stroke volume
185
what conditions may be caused by a poor diet?
high fat/ sugar diet:
-high blood pressure
-depression
-heart disease
-strokes
-type 2 diabetes
low calcium diet:
-osteoporosis
too much red or processed meat:
-bowel cancer
186
what conditions can be caused by high levels of stress?
depression
asthma
can increase factors of obesity, heart disease, diabetes, alzheimers
187
what conditions can be caused by life situation?
stress
mental illness
188
how can being overweight increase the risk of a stroke
having high pressure is strongly related to being overweight
this damages the body’s arteries in the long term by making the walls thick and stiff. this may cause a blood clot in a brain’s vessel, causing a stroke
189
what is the link between infection of a pathogen and asthma?
pathogens can cause immune reactions which can cause allergic reactions
severe viral respiratory infections in childhood can lead to the development of asthma as the child grows, as the body can attack itself the lungs as well as the virus
this can trigger asthma
190
what is the link between cancer and mental health problems?
severe physical ill health like cancer can cause depression or other mental illnesses
191
what is SCID
severe combined immunodeficiency
a group of rare inherited disorders which cause severe abnormalities of the immune system
this happens when white blood cells are missing or working poorly
this results in serious or life threatening infections
192
what is a pathogen?
a disease-causing microorganism
193
how does the body respond to allergen?
the immune system produces antibodies to fight off the allergen
the first time it is encountered, the immune response is smaller than the subsequent times
with repeated exposure, the body produces large amounts of the specific antibodies and stimulate the cells to release histamine, the chemical that produces allergic symptoms
this helps expel the allergen out of the body
194
how can diet affect the incidence on non-communicable diseases?
a better diet without processed foods can reduce your chance of cancer
a high cholesterol diet can lead to build ups of atheroma which lead to blocked arteries and strokes or heart attacks
195
how can alcohol consumption affect the incidence of non communicable diseases?
drinking alcohol has been linked to mouth, liver, breast and stomach cancers
alcohol consumption helps prevent kidney cancer
it is a depressant, so can lead to depression or memory loss
alcohol withdrawal symptoms can lead to raised pulse, nausea, headaches, insomnia, anxiety and depression
alcohol increases your blood pressure and heart rate which can lead to other things
196
how does smoking affect the incidence of non-communicable diseases?
cigarettes contain over 60 carcinogens
carbon monoxide binds easier to haemoglobin easier than oxygen, so the blood carries less oxygen which can cause anemia
chemicals in cigarette smoke increase the likelihood of blood clotting, which can cause a stroke or a heart attack
197
what are the risk factors for cardiovascular disease?
poor diet
smoking
no exercise
198
what are the risk factors for type II diabetes?
obesity
199
what are the risk factors for liver and brain damage?
alcohol
200
what are the risk factors for lung disease and cancer?
smoking
201
what are the risk factors for low birth weight or premature birth?
smoking
202
what are the risk factors for abnormal foetal brain development?
alcohol
203
what are the risk factors for cancer?
carcinogens, smoking, obesity and radiation
204
what is cancer?
the result of changes in cells that lead to uncontrolled growth and division (mitosis)
205
what is a benign tumour?
a mild tumour which doesn’t spread
206
what is a malignant tumour?
spreads to other parts of the body and forms secondary tumours
this is called metastasis
207
how does cancer happen?
chromosomes are damaged
cancerous cells multiply to form a tumour within a block of tissue
the tumour cells enter the bloodstream and cancer is spread through the body
208
what is vasoconstriction?
when your capillaries and arteries are thinner because it is cold
209
what is vasodilation?
when your capillaries and arteries are wider and the blood is closer to the surface of the skin
210
what is myopia?
when the eyeball is too long for the strength of the lense, the lense is too strong/ thick or the cornea is too sharply curved
when the eye attempts to produce an image, it falls short of the retina
the image focuses in front of the retina
211
what is hyperopia?
when the eyeball is too short for the strength of the lense, the lens is too weak/thin or the cornea isn’t curved enough
when the eye wants to produce an image, it falls behind the retina
the image focuses behind the retina
212
what are stents?
needed when blood vessels are blocked with cholesterol plaque
carried out with a catheter and a balloon
213
what are the advantages of stents?
little risk to the patient
reduces pain
increases quality of life
214
what are the disadvantages of stents?
the fatty deposits can rebuild
can cause blood clots
215
what is an artificial pacemaker?
needed when the patient’s heartbeat needs electrical pulses to control it
a wire is attached from their vein to the right atrium
216
what are the advantages of an artificial pacemaker?
major surgery isn’t needed
can eliminate shortness of breath
217
what are the disadvantages of an artificial pacemaker?
can be rejected by the immune system
can cause infections
218
what is an artificial valve?
used to replace heart valves when they are damaged from disease or age
if not fixed, the blood can flood back, meaning oxygenated and deoxygenated blood can mix
they can be biological, inserted through a small leg incision or mechanical, inserted with open heart surgery or a catheter in the leg
219
what are the advantages of a biological valve?
red blood cells won’t be damaged
won’t be rejected by the body
220
what are the disadvantages of biological valves?
they can harden so may need replacing
221
what are the advantages of mechanical valves?
won’t be rejected by the body
222
what are the disadvantages of mechanical valves?
can damage the red blood cells, so anti clotting drugs may be needed
223
how can plant diseases be identified?
consulting a garden manual or website
using monoclonal antibodies testing kit
taking the infected plant to a lab for expert advice
224
what are the mechanical responses of plants?
thorns and hairs
mimicry
leaves drop/ curl when touched
225
how do thorns and hairs help plant defence?
hairs prevent larvae from reaching the epidermis to feed
thorns impale insects and prevent eggs laying
they also deter grazing herbivores and wear down their teeth
226
how does mimicry help plant defence?
features trick animals into not feeding or laying eggs
some grasses and hollyhocks have stem markings that look like aphids
227
What is the function of a capsule?
for protection/sticking prokaryotic cells together
228
What is the function of a flagella?
movement
229
What is the function of the pili?
for sticking to surfaces, such as cells to spread disease
230
What are plasmids?
extra bits of circular DNA for antibiotic resistance
231
What are the main organelles in a eukaryotic cell?
cytoplasm
nucleus
cell membrane
ribosome
mitochondria
232
What is the relative size of bacterial cells?
Smaller than a eukaryotic cell
233
How is genetic material found in a eukaryotic cell?
rings of DNA
234
How is genetic material found in a prokaryotic cell?
in the nucleus
235
What conditions can be helped by stem cell treatment?
Parkinson's, cancer, heart disease
236
What are some of the substances transported in and out of cells by diffusion?
oxygen and co2 and urea
237
What is the pH of bile?
8
238
What factors affect the rate of transpiration?
humidity
light intensity
wind
temperature
239
Why is it difficult to develop drugs that kill viruses?
viruses 'live' inside cells, so it is very hard to kill the virus without also killing the cell it is living in
240
Where are plant stem cells found?
in the meristem (roots and shoots)
241
What are some possible uses for plant stem cells?
to prevent extinction
economic benefit
food production
research
disease resistance
242
What are some ethical/religious concerns about stem cell use?
destroying the embryo
umbilical cord stem cells need mother's consent
243
What are some risks associated with stem cell use?
cells can behave like cancer
immunosuppressant drugs often needed
244
What factors affect the rate of diffusion?
temperature
concentration gradient
surface area
245
What factors increase the effectiveness of an exchange surface?
-large SA to increase the exchange site
-thin walls/ membrane, decreases diffusion distance
-a good blood supply to maintain a steep concentration gradient
-well ventilated for gaseous exchange (IN ANIMALS)
246
How is active transport used in root hair cells?
to absorb nitrate ions from soil water
247
How is active transport used in villi in the small intestine?
to absorb amino acids and glucose into the blood
248
What is in an organisational hierachy?
organelle →cells → tissues → organs → organ systems
249
What is denaturation?
When the active site of an enzyme changes and no longer fits the substrate
250
What is the purpose of digestive enzymes?
To convert food into small soluble molecules which can be absorbed into the bloodstream
251
How can the spread of disease be reduced?
preparing food hygienically, washing, vaccination
252
Name 3 diseases caused by a virus
measles, HIV, TMV
253
Name 2 diseases caused by bacteria
Salmonella, gonorrhoea
254
Name a disease caused by a protist
malaria
255
Name a disease caused by a fungus
rose black spot
256
How is measles transmitted?
droplet infection
257
How is HIV transmitted?
direct contact of bodily fluids
258
How is salmonella transmitted?
contaminated food
259
How is gonorrhoea transmitted?
unprotected sex
260
How is malaria transmitted
mosquito bites
261
How is rose black spot transmitted?
spores from a parasitic fungus
262
How is TMV transmitted?
wounds in the plant skin or epidermis
263
What are the symptoms of measles
fever/ red rash
264
What are the symptoms of HIV?
weak immune system
AIDS
flu-like symptoms
265
What are the symptoms of salmonella?
vomiting
stomach aches
diarrhoea
266
What are the symptoms of gonorrhoea?
vaginal/penile discharge
pain urinating
267
What are the symptoms of malaria?
fever
muscle pains
cough
headache
268
What are the symptoms of rose black spot?
black spots on leaves
leaves turn yellow
269
What are the symptoms of TMV?
discoloured mosaic/mottling on leaves
270
How can measles be prevented?
MMR vaccination
271
How can HIV be prevented?
Antiretroviral drugs (stop the virus replicating)
272
How can salmonella be prevented?
vaccination animals
hygenic conditions
273
How can gonorrhoea be prevented/ treated?
condoms
antibiotics
274
How can malaria be prevented/ treated?
Spraying pools of stagnant water with:
-insecticides to kill mosquitoes
-oil to suffocate the larvae
drain stagnant water pools
mosquito nets
taking drugs to kill the protist in the blood
275
How can TMV be prevented/ treated?
removing infected plant materials
controlling pests
sterilising tools
washing hand after handling infected plants
276
How can rose black spot be treated?
removing and burning dropped leaves
pruning and burning shoots
fungicides
surrounding plants with manure to stop fungal spores from reaching the stems
277
What is herd immunity?
resistance to an infectious disease within a population based on a high proportion of the population being immune. this makes it harder for the virus to spread to people who aren't immune
278
What is a painkiller?
a chemical that relieves the symptoms but doesn't kill the pathogen
279
What factors affect the rate of photosynthesis?
light intensity
CO2 concentration
temperature
chlorophyll shortage
280
What are the symptoms of a magnesium deficiency?
yellow leaves
281
What are the symptoms of a nitrate deficiency?
poor growth, yellow leaves
282
What are the symptoms of a potassium deficiency?
poor growth of fruits and flowers, discoloured leaves
283
What are the symptoms of a phosphate deficiency?
poor root growth, discoloured leaves
284
What is the inverse square law (photosynthesis)?
If you move the light source double the distance, the intensity will quarter
intensity = 1/ distance^2
285
How do watering systems increase food production in greenhouses?
regular, equal amounts of water to each plant without labour
286
How do hydroponics increase food production in greenhouses?
this is growing plants in mineral solutions without soil- expensive but effective
287
How does shading increase food production in greenhouses?
controls light and temperature
288
How do biological control increase food production in greenhouses?
pesticides aren't used- living organisms in a closed growing environment
289
How do humidifiers increase food production in greenhouses?
reduce water loss via transpiration, reducing the need for water
290
How do heaters increase food production in greenhouses?
control temperature and co2 concentration (paraffin heaters)
291
How does the sun increase food production in greenhouses?
faster rate of photosynthesis (but can denature enzymes)
292
How does ventilation increase food production in greenhouses?
helps control humidity and temperature
293
What are the uses of glucose in plants?
Respiration
Starch for energy storage
Proteins for growth and repair
Cellulose to strengthen cell wall
Oils and fats for energy storage
294
What do organisms need energy for?
Movement
Respiration
Sensitivity
Growth
Reproduction
Excretion
Nutrition
295
What is homeostasis?
the regulation of the internal conditions of a cell or organism to maintain optimum conditions for function in response to internal and external changes
296
Name 3 levels controlled by homeostasis
blood glucose concentration
body temperature
water levels
297
What can automatic control systems involve
nervous or chemical responses
298
What is a receptor?
cells which detects changes in the environment
299
What is purpose of a coordination centre?
to receive and process information from receptors
300
Name 3 examples of coordination centres in the body
brain
spinal cord
pancreas
301
What is an effector?
muscles or glands which bring about responses to restore optimum levels
302
What is the main function of the nervous system?
to enable humans to react to their surroundings and coordinate their behaviour
303
What is binary fission?
cell division
304
Describe the SA:V ratio in single-celled organisms
relatively larger to allow sufficient transport of molecules into and out of the cell
305
How is the small intestine adapted for exchanging materials?
villi, for a large surface area, shorter diffusion path and rich blood supply
306
How are the lungs adapted for exchanging materials/ gaseous exchange?
well ventilated
capillaries ensure good blood supply and steep concentration gradient
alveoli provide a large surface are and are very thin, so there is a smaller diffusion distance
307
How are gills adapted for exchanging materials?
good blood supply
continuous water flow
gills made of thin filament stacks (large surface area and smaller diffusion distance)
308
How are roots adapted for exchanging materials?
large sa (root hair cells)
constant water flow
309
How are leaves adapted for exchanging materials?
flat, so have a large surface area
thin walls
stomata to allow movement of gases
310
How are enzymes linked to metabolism?
chemical processes within a cell require an enzyme to speed up the reaction-the enzyme helps to increase or decrease the rate of metabolism in the body
311
What is health?
The state of physical and mental wellbeing
312
What is the function of epidermal tissues?
The upper epidermis is transparent to let light through for photosynthesis
The lower epidermis contains guard cells
313
What is a limiting factor?
anything that slows or stops a process
314
What is a placebo?
a substance with no chemical effects given to a patient instead of a drug
315
What is a double blind trial?
a trial where neither the researchers nor the patients know whether they are getting a placebo
316
How do plants use nitrate ions from the soil?
to make proteins
317
Why does anerobic respiration take place in muscles in exercise?
there isn't sufficient oxygen present in the muscle cells
318
What is the liver's role in the removal of lactic acid?
The blood flow through muscles removes lactic acid and transports it to the liver.
319
How is the nervous system adapted to its functions?
Nerve cells (neurons):
- have a long fibre to carry messages long distances
- their axons are insulated by a myelin sheath, which increases the speed of nerve impulses
320
Define hormones
A chemical substance produced by a gland and carried in the bloodstream
321
State 5 metabolic processes
breaking down glucose, making glucose, breaking down fat, making ATP, the krebs cycle
322
What is a metabolic process?
A chemical reaction in the cells of an organism
323
How have neuroscientists been able to map the regions of the brain to particular functions?
MRI scans, CT scans, EEGs
324
What is an MRI scan?
Magnetic resonance imagery
325
What is a CT scan?
Computed tomography scan- uses x rays. It is easier to use than MRI, although there is some risk of radiation and injected dyes
326
What is EEG?
electroencephalography- small sensors are placed all over the scalp to detect electrical brain signals. It can't be used to detect cancer.
327
