1
Q
what is Hb and how does it make blood red?
A
- a red pigment (protein) used to transport O2 in the blood
2
Q
Association definition?
A
the binding of 2 molecules, commonly used in biology when referring to the loading of O2 onto Hb
3
Q
why can Hb transport O2?
A
bc this reaction is reversible - dissociation can also occur
4
Q
Dissociation definition?
A
The separation of 2 molecules, commonly used in bio when referring to the unloading of O2 from Hb
5
Q
what is Hb made up of?
A
- 4 polypeptide chains each containing a prosthetic Haem group
- 2 chains r alpha globin and 2 are beta-globin
- 1 O2 binds to each Haem group
6
Q
what is a saturated Hb?
A
all haem groups bond - 4 O2
7
Q
what can the partial pressure of O2 tell us?
A
how much is bound to the Hb compared to how much there is
8
Q
O2 dissociation curve - steep part?
A
- once the first O2 binds, POSITIVE CO-OPERATIVITY caused by the conformational change in Hb causes the gradient to steeply increase
9
Q
why must Foetal Hb have a higher affinity for O2 than adult?
A
- fetus = not breathing, adult Hb needs to release O2 so can get it
10
Q
animals that have a high altitude have a ? affinity for O2?
A
- higher affinity than those who live at lower altitudes
11
Q
where does CO2 bind to Hb?
A
NOT Haem group, but to amino groups of Hb, hence carbAMINOhaemoglobin
12
Q
The Chloride Shift definition?
A
the movement of Cl(^-) into the erythrocytes to balance the charge as HCO3 (^-) leaves the cell
13
Q
if Hb didn’t act as a buffer, what could the H+ ions do?
A
denature proteins
14
Q
why does atrial systole only generate a small increase in pressure?
A
the atria only have thin walls
15
Q
why does the pressure in arteries go up and down? (paper flashcard graph)
A
- the walls of arteries have thick layers of ELASTIC TISSUE which allow them to stretch and recoil with the pumping of the heart
- these fluctuations become less dramatic in arteries away from the heart and have vanished by the time blood reaches the arterioles
16
Q
why does the blood pressure drop to almost 0 in the capillary beds?
A
as lots of capillaries = high overall friction
17
Q
why is cardiac muscle known as myogenic?
A
can beat w/o signals from the brain - can inititate its own contractions
18
Q
what can lead to fibrillation?
A
- muscles in the atria naturally contract faster than muscles in the ventricles
19
Q
what is fibrillation?
A
the uncoordinated contraction of the muscles in the heart
20
Q
what is the danger of a fibrillating heart pump?
A
- it pumps blood much more inefficiently and increases the chances of angina (pain in the chest: heart starved of O2) and myocardial infarction (heart attack: part of heart muscle dies due to the lack of O2)
21
Q
What does the heart do to avoid fibrillation?
A
co-ordinate its contractions using 3 types of tissue: AVN, SAN, purkyne fibres
22
Q
what is the SAN ?
A
A small patch of tissue that generates electrical impulses 55 -80 (heart rate) x a min
23
Q
AVN?
A
- the base of the Atria can’t conduct elec with the exception of another small patch of tissue - AVN
- It delays the impulse before passing it down through the conductive Purkyne muscle tissue
24
Q
what does the AVN delaying the impulse allow?
A
- blood has time to be squeezed from atria -> v
- allows time for V to fill
25
the Purkyne tissue ensures?
- that contractions in the ventricles starts at the bottom so blood is squeezed up & out through the arteries
(PT at the bottom contracts 1st)
26
how is coordination of the heart tissue achieved?
| AVN & Purkyne
by delaying the impulse at the AVN and starting ventricular systole at the base of the heart co-ordination of the heart beat is achieved
27
why can electrical sensors be attached to the skin to detect impulses?
- the electrical impulses of the heart can spread through e.g. extracellular fluid to nearby tissues
- by attaching electrical sensors to skin, these impulses can be detected
- can be converted into ECG traces
28
why can measuring heart beat inform a medical diagnosis?
an unhealthy heart often beats irregularly
29
why is one single heart beat not used in an ECG?
- not reliable enough so ECG traces are long containing many beats
30
bradycardia =?
abnormally slow heart rate
31
tachycardia =?
abnormally fast heart rate
32
atrial fibrillation =?
w/o the correct coordination of the heart, the atria tend to beat more rapidly than the V (wiggly lines for P wave)
33
ectopia = ?
irregular heart beat
34
cardiac cycle definition?
the seq. of events that occur within one full heart beat
35
what do the semi lunar valves do?
keep BP ⬆ in the arteries and prevent blood from flowing back into the heart during diastole
36
Why do large, active, multicellular organisms need specialised transport systems?
bc DIFFUSION IS NOT SUFFICIENT TO SUPPLY CELL'S DEMAND for molecules e.g. O2 and glucose
37
why is diffusion not sufficient to supply cell's demand in large, active, multicellular organisms?
- size
- SA:V
- metabolic activity
38
all circulatory systems have?
- a liquid transport medium (blood or haemolymph)
- vessels to carry the transport medium
- have a pump (heart or hearts) to move the transport medium
39
a circulatory system can be:?
- open = the transport medium is not enclosed in vessels
| - closed = the transport medium is enclosed in vessels
40
a closed system can be?
```
single = only one circuit
double = 2 circuits
```
41
open circulatory system (insects)?
- haemolymph is moved through the body cavity (haemocoel) by the contraction of simple hearts which contain a single valve
42
advantages of open circulatory systems?
- system is energetically efficient
| - low levels of ATP needed to maintain flow
43
disadvantages of open circulatory system?
- low pressure, so delivery for cells is slow
| - limited control and distribution of 'blood' flow
44
hemolymph (insect)?
does NOT transport O2 or CO2, transports the product of digestion (e.g. glucose) to respiring cells
- gas exchange = tracheal system
45
closed circulatory system (fish)?
- single, closed
- in a closed, blood is enclosed in blood vessels and does not come directly into contact with the cells of the body
- in a single, the blood flows thru the heart and is pumped out to travel all around the body b4 returning to the heart
- blood passes through 2 sets of capillaries before returning to the heart.
- in the 1st, exchange O2 and COS, 2 - substances exchanged between the blood and cells
46
-s of CCS?
limited efficiency of exchange processes so the activity levels of animals with single closed circulations tend to be low as the blood pressure drops and returns to the heart slowly due to passing through 2 sets of vert narrow vessels
47
double closed (mammals)?
- double has 2 separate units:
- one to excrete CO2 and to pick up O2 from the lungs - the pulmonary circuit
- one to deliver O2 and pick up CO2 from the respiring body cells - the systematic circuit
- the 2 circuits are connected by a 2 sided, 4 chambered pump, the heart
48
+s of double closed?
- each circuit of the body only passes through 1 capillary network which a high pressure and fast flow of blood can be maintained
- the amount of blood flowing to a particular tissue can be adjusted by widening or narrowing blood vessels
49
incomplete double system (amphibians and some reptiles)?
- amphibians have a 3 chambered heart - 2 atria and 1 ventricle
- the mixing of oxygenated and deoxygenated blood is kept to a min due to the timing of the contractions between the atria
- amphibian lungs are balloon like structures where gas exchange is limited
- as a result, O2 can be diffused thru their moist skin (and mouths sometimes) to compensate
- ox blood is received by the left atrium and deox blood is received by the right atrium, but the blood gets mixed up in the single ventricle which pumps out the mixed blood. the blood comes to the heart through 2 different route, but goes out through a single route
50
+ of incomplete double system?
high pressure in the vessels pushes blood to the lungs and body
51
- of incomplete closed system?
less efficient - mixing of ox and deox blood
52
what do arteries do?
carry oxygenated blood at high pressure from the left ventricle to all respiring cells in the body
53
what do arterioles do?
dilate and constrict controlling the distribution of oxygenated blood into the capillaries of the body
54
what do capillaries do?
the site of gas exchange between erythrocytes and tissue fluid, and therefore cells. Also responsible for TF formation
55
what do venules do?
carry deox blood from capillaries into the veins
56
what do veins do?
return deox blood from the cells of the body back to the right atrium of the heart
57
arteries and veins have walls w ? layers?
3
58
tunica externa?
- outer layer
- elastic fibres stretch and recoil
- collagen = mechanical strength/protection
59
order of layer in arteries/ veins?
lumen -> tunica intima -> tunica media -> tunica extrema
L
I
M
E
60
tunica media?
- smooth muscle cells = allow constriction + dilation
- collagen fibres = give walls mechanical strength
- elastic fibres = allow walls to stretch and recoil
61
tunica intima?
A Single layer of squamous epithelial cells - a low friction surface
62
systole?
contraction of heart muscle - heart is pumping
63
diastole ?
heart is relaxing (d for dead)
64
elastic recoil?
- when the heart is pumping, the walls of the arteries are stretching due to the high pressure of blood
- when the heart is not contraction (diastole ) the diastolic pressure remains high due to the walls of the arteries recoiling, squeezing the blood, keeping the pressure high
65
composition of blood - cell and cell fragments?
- leukocytes - WBCs e.g. neutrophils, macrophages, lymphocytes
- erythrocytes
- platelets
- ALL OF THE ABOVE ARE SUSPENDED *NOT* DISSOLVED. THEY DON'T CONTRIBUTE TO THE BLOOD WATER POTENTIAL
66
blood plasma composition?
- Water with the following in solution:
| - plasma proteins e.g. albumin, fibrogen, enzymes, antibodies
67
products of digestion and other substances synthesised by the body are also in the blood e.g.?
- amino acids
- glucose
- fatty acids
- glycerol
- vitamins
- cholesterol
- ions e.g. Na+,K+, Cl-, HCO3-...
- hormones e.g. insulin
- urea
68
TF formation?
- at the arterial end of capillary, hydrostatic pressure (4.6kPa) is > Oncotic pressure (-3.3kPa), TF forms - small molecules are forced through fenestrations in capillary endothelium
- OP is caused by the large plasma proteins that stay in the blood, lowering WP and so water potential gradient exists between blood and TF
- at the venous end of capillary, oncotic pressure (-3.3kPa) is > than 2.3 kPa so TF reabsorbed
69
TF is being constantly?
formed and reabsorbed
70
what allows the TF formation?
fenestrated wall of capillary - endothelium (not epithelial as not outside)
71
what does not change?
OP
72
what is TF?
blood plasma w/o the larger cells/ molecules
73
how much TF drains into the lymphatic system?
10%
| lymph to lymphatic system
74
why is TF formed at the arterial end?
- arterial end has a high HP
- OP is caused by the large plasma proteins that stay in blood, lowering the ψ and so a ψ gradient exists between the blood and TF
- HP is greater (4.6kPa) than OP (-3.3 kPa so TF is formed meaning small molecules are forced out the fenestrated wall of capillary endothelium
75
why is TF reabsorbed at the venous end of a capillary network?
- 90% of TF is reabsorbed at the venous end of the capillary as HP (-2.3kPa) (falls as blood flows at low pressure further away from the heart)
- OP doesn't change as the conc doesn't change (still the same things dissolved in the capillary)
- meaning OP > HP so TF is reabsorbed
76
medical con associated with TF: kwashiorkor?
- low protein diet as put onto solid food as no longer breast fed due to younger sibling - diet around carbohydrates not protein
- less protein in blood, lowering conc of blood, reducing OP
- more TF is formed
- less TF is also reabsorbed bc hydrostatic pressure is still low but as OP is still lower (stays same ) due to lower blood conc
77
medical con associated with TF: elephantiasis?
parasitic worms get injected in blood by host (mosquito) and then get into the capillary and eat their way through the cells. they get into the lymphatic system, blocking vessels when TF is drained as there is an ideal temp for reproduction and survival in the lymphatic system .
78
acronym for heart?
```
Left
Atira
Bicuspid
Right
Atria
Tricuspid
```
79
what to label on a heart diagram?
chambers, vessels, valves
80
the coronary circulation?
- ox blood enters CA from the aorta
- coronary arteries supply the cardiac muscle of the heat w O2
- blockages/ narrowing of these arteries can cause reduced blood flow
- angioplasty - stents can be used to open up the artery or coronary bypass surgery uses an artery/ vein from elsewhere in the body (e.g. leg) to bypass the blockage and allow blood flow around the blockage, impov bf to heart
81
the cardiac cycle?
- a series of events that cause pressure changes in the heart and therefore blood to flow through the heart
1 - atrial systole - atrioventricular valves snap shut at beg
2 - ventricular systole - semi lunar valves snap shut -
3 - diastole
82
how does blood flow in the heart?
hi -> lo pressure, down a pressure gradient
- this can only happen if a valve can open, allowing blood flow
- if a valve snaps shut, blood flow is prevented
83
1- the pressure in the ventricle exceeds the pressure in the atrium so....
the valve between the left atrium and the left V (bicuspid ) closes
84
2 - closure of the bicus valve and contraction of the ventricle means that...
the pressure in the V increases
85
3- when the pressure in the LV exceeds the pressure in the aorta...
the semi-lunar valves are forced open
86
4- the opening of the semilunar valves results in blood leaving the ventricle entering the aorta. this results in...
an increase in pressure in the aorta
87
5- as blood enters the aorta, the V is still contracting so...
the pressure in the V continues to increase a little b4 falling as the V starts to relax
88
6- as the pressure in the V now falls below the pressure in the aorta causing....
the semi lunar valves close, preventing a backflow of blood from the aorta to the ventricle
89
7 - the pressure in the ventricle now falls below the pressure in the atrium causing....
the biscuspid valves to open
90
what does ECG stand for?
ElectroCardioGram
91
cardiac muscle is?
myogenic- can contract w/o external neuronal stimulus
92
skeletal/ smooth muscle is?
neurogenic - needs an external neuronal stimulus to contract
93
what does AVN stand for?
Atrioventricular node (V for middle)
94
What does SAN stand for?
sino- atrial node
95
P wave ?
- atrial systole
| - electrical activity sweeps through the walls of the atria causing them to contract
96
PR segment?
a delay as electrical activity passes through the AV node and into the bundle of His
97
QRS complex?
- Ventricular systole
- electrical activity passes down the interventricular septum to the apex of the heart via the bundles of His. Purkyne fibres carry the impulses into the ventricular walls which then contract upwards, fromm the apex
98
T wave?
- diastole
| - cardiac muscle relaxes and repolarises
99
need to know which 5 heart conditions?
- bradycardia
- tachycardia
- atrial fibrillation
- ectopic heart beat
- ventricular fibrillation
100
tachycardia?
- over 100
- symp: feel faint, pale, palpitations
- treatments: drugs, beta blockers, pace maker, life style changes
- graph looks very fast
101
bradycardia?
- symp: faint, pale
- treat: drugs, pacemaker
- graphs looks too slow
102
ectopic heart beat?
- normal unless happens a lot
| looks normal but with some irregularity
103
atrial fibrillation? s&t
s: faint, pale, worried
t: drugs, surgery, pacemaker
- graph looks fairly normal, but beats closer together
104
VF?
- Medical emergency
- S: crushing [ain, very serious
- T: CPR, defibrillation, surgery
- graph looks totally wrong, squiggly lines
105
how does Hb bind to O2 ?
hb has 4 subunits w a Haem prosthetic group at the centre of each subunit
the Fe ion at the centre of each haem can bind to 1 O2
106
Hb + 4O2 ->
HBO8- Oxyhaemoglobin
forwards in lungs
backwards at respiring tissues - this reaction is called O2 dissociation - is shown by an S Shaped sigmoid curve
107
why is the O2 dissociation curve S shaped- sigmoid?
A: + cooperativity
the first O2 molecule is diff to bind to Hb. The binding of the first O2 causes a conformational change which makes the binding of the next 3 O2 easier (steep part of the graph)
108
how does Hb's affinity for O2 affect the O2 dissociation curve?
- if Hb's affinity for O2 decreases, then the graph shifts to the right
- e.g. : 1 - the Bohr shift- when CO2 is high in respiring tissues, Hb 'gives up' its O2 more easily
2 - temp increase - this decreases the affinity of Hb for O2
109
affinity =?
the degree of 'stickiness' Hb has for O2. Can change
110
what happens in the Bohr shift?
- the O2 dissociation curve shifts to the right in high pCO2
| - hb reduced its affinity for O2
111
why does the Bohr shift happen?
(more detail needed) more CO2= more carbonic acid as HbO8 binds to the H+ ions produced by the dissociation of H2CO3 which causes the O2 to be released to respiring cells. this means that the Hb is less saturated
112
why is the Bohr shift beneficial for active muscle tissues?
- active muscle tissues respire a lot, so there is a high pCO2 in the tissue
- this means that more CO2 reacts with H2O forming carbonic acid
- H2CO3 dissociates into H+ and HCO3-
- The H+ displace O2 by reacting w HBO8, releasing O2 to respiring cells
- the high levels of CO2 cause more H+ to be formed and so more O2 is released, this means that the saturation of the Hb molcules decreases more and the affinity of Hb for O2 decreases
113
fetal Hb?
- has a higher affinity than adult Hb
| - this ensures that in the placenta (where pO2 is low) O2 is transferred from maternal to fetal Hb
114
after 6 months after birth, all fetal Hb has been replaced by adult Hb. Why is this imp?
- Hb would have a higher affinity for O2 -> harder for the O2 to dissociate
- respiring cells wouldn't get enough O2 -> but replacement can happen after 6 months and not directly after birth bc babies ae not very active, so the O2 demand isn't high
2- if the foetus then goes on to get preg when older, and it still had foetal Hb, there would be no O2 transfer to the foetus (no diff in affinity)
115
myoglobin?
- a muscle protein found in the muscles of deep diving aquatic mammals e.g. mammals, cetaceans (whales dolphins, ect..)
- acts as an O storage molecule, only releasing O2 at V low partial pressures
- has a very high affinity for O2
116
CO2 transport in the blood?
overall, increasing pCO2 reduced the affinity of Hb for O2, supplying more O2 to the respiring cells that produced the CO2 that caused the effect in the first place
117
CO2 transport in the blood?
- 5% of the CO2 dissolves directly into the blood plasma, and the other 95% diffuses across the erythrocyte membrane into the erythrocyte
- 10% of the Co2 binds to Hb forming Carbaminohaemoglobin
- 85% of the Co2 reacts w water to form carbonic acid: H2CO3- this reaction is catalysed by the enzyme carbonic anhydrase
- HbO8 combines with excess H+ ions forming haemoglobinic acid
118
specialised transport systems are needed in animals bc:
- high metabolic demands
- small SA:V
- molecules e.g. hormones/ enzymes made in one place but needed in another
- every cell needs the products of digestion for respiration
- removal of waste products
119
what is a mass transport system?
when substances are transported in a mass of fluid with a mechanism for moving the fluid around the body
120
-s of SCCs?
- blood passes through 2 sets of capillaries so BP drops and the blood returns to the heart slowly. this limits the efficiency of exchange processes so the activity levels of animals with SCCs tend to be low
121
what does collagen do?
provides structural support to maintain the shape and volume of the vessel
122
arterioles structure?
- link arteries and capillaries
- they have more SM and less elastin in their walls than arteries,
- as they have little pulse surge, but can constrict or dilate to control the flow of blood into indiv organs.
- when the SM in the arteriole contracts, it constricts the vessel and prevents the blood flowing into a capillary bed - vasoconstriction.
123
adaptations of capillaries?
- V large SA for the diffusion of substances in and out of blood
- the total cross sectional area of the capillaries is always greater than the arteriole supplying them so the rate of BF falls. The relatively slower movement of blood through capillaries gives time for exchange of materials by diffusion between the blood and the cells
- the walls are a single endothelial cell thick, giving a very thin layer for diffusion
124
why do veins not have a pulse?
the surges from the heart pumping are lost as the blood passes through the narrow capillaries
125
Artery pressure and speed of blood movement?
High pressure. Blood flows at a high rate.
126
Artery lumen size?
1-15mm
127
Artery structure?
many elastic fibres, collagen fibres, smooth muscle
128
Artery valves?
no need - high pressures ensures unidirectional flow of blood
129
Artery role?
carry blood away from the heart to tissues of the body
130
Artery e.g.s?
aorta & renal artery
131
Artery other info?
* arterioles link arteries and capillaries
| * high pressure maintained by elastic recoil
132
Capillaries pressure and speed of blood movement?
blood travels through in single file, slow flow, V low pressure
133
Capillary lumen size?
7-10 micrometres
134
Capillary structure?
* fenestrated endothelium
| * very thin, single layer of endothelium with gaps between cells
135
Capillary valves?
• too small for valves
136
Capillary role?
* microscopic blood vessels that link arterioles and venules
* form a network throughout all tissues of the body
* exchange of substances between blood and tissue fluid
137
Capillary other info?
* large SA
| * total cross sectional area> arteriole
138
Vein pressure and speed of blood movement?
low pressure
139
Vein lumen size?
1-25mm
140
Vein structure?
large lumen, thinner walls than A, little smooth muscle, elastic fibres, more collagen
141
Vein valves?
semilunar valves present
142
Vein role?
returns deox blood to heart
143
Vein other info?
muscular pump ensures flow of blood
144
endothelium structure and function?
S: single layer of cells#
F: smooth, low friction surface
145
elastic layer structure and function?
S: elastic fibres made of elastin
F: stretch and recoil
146
SM structure and function?
F: contract to constrict vessels, relax to dilate
147
collagen layer structure and function?
S: collagen fibres
F: mechanical strength. protection
148
Blood vessels go
Aorta ➡ artery ➡ arterioles ➡ venules ➡ veins ➡ vena cava
149
area as blood vessels go?
* graph peaks in the middle
* as the number of vessels increases, the cross sectional area inc
* CX at max in capillaries
150
velocity as blood vessels go?
* the flow rate decreases as cross section inc
* As CX inc, the blood slows down from peak flow rate in arteries
* in capillaries blood is barely moving - rapid fall
* the muscular pump keeps blood in veins flowing towards heart - causes velocity to pick up again
151
pressure as BV go?
* pressure fluctuates in the arteries
* this is the pulse and is kept high by elastic recoil
* pressure drops through the capillaries to almost 0 in veins
wobbly at start, rapid fall, then almost at 0 for veins
152
what is the function of valves in veins and how does the muscular pump work?
* skeletal muscles squeeze veins returning blood to heart, putting pressure on em
* valves prevent backflow of blood
153
dissolves molecules presence in TF and lymph?
e.g. urea, glucose, CO2, O2
TF: yes, but less e.g. glucose and more urea
L: yes but less O2 and more glucose and more FA absorbed from DS
154
Lymph?
* invoved in defence against pathogens
* transported through evssels by squeezing of body muscles
* one way valves prevent backflow of lymph
155
lymph nodes?
* lymphocytes build up and produce antibodies which are then passed into blood
* lymph nodes also interpret bacteria from lymph which are ingested by phagocytes, found in the nodes
* enlarged lymph = sign of pathogen invasion
156
lymphatic system is?
a system that drains 10% of the TF from the tissues of the body, returning it via lymphatic capillaries, lymphatic vessels, lymph nodes and the thoracic duct to the blood in the subclavian veins
157
right side of heart?
deox
158
left side?
ox
159
remember, the diagram shows?
the heart of a person stood facing you, your left is their right
160
pulmonary vein?
ox blood from lungs
161
superior vena cava?
supplies deox blood from the body
162
aorta?
carries ox blood to whole body except lings
163
pulmonary artery?
to lungs to get ox
164
tri and bicuspid values are?
atrioventricular valves
165
semi-lunar valves?
prevent backflow of blood from artery to ventricle
166
stages of cardiac cycle?
* atrial systole - atria contracts, pumping blood from atria ➡ ventricle
* ventricular systole - ventricles contract, pumping blood into heart
* diastole - no contraction, refill with blood for next contraction
167
lub dub sound?
* at the b of ventricular systole, atrio ventricular valves snap shut - lub
* at end of VS, semi lunar valves snap shut - dub
* diastole - stop
168
CO2 transport in the blood?
* produced by resp
| * diffuses into TF then into plasma in capillaries
169
When Hb acts as a buffer to remove the excess H+ ions?
* haemoglobinic acid forms
| * displaces O2
170
at the lungs?
* the CO2 that dissolved in the plasma comes out of solution and diffuses into the alveoli to be excreted during ventilation
* carbaminohaemoglobin releases CO2 which diffuses into alveoli
* Cl- shift reverses, carbonic acid reforms which splits back into CO2 nd H2O, CO2 excreted
171
Wiggers diagram?
A) A>V pressure so blood flows thru bicuspid valve
B) • semilunar valve is closed, aortic pressure is greater than ventricular pressure
• ventricular pressure becomes higher than aortic so SLV opens
172
Wiggers diagram 2 ?
• at the start ventricular pressure> aortic
• then aortic pressure inc so semi lunar valve shuts
D) artial pressure > ventricular so BV opens
A Level Biology
flashcards
Decks in class (28)
# Cards
-
Chapter 3 Biological molecules142
-
Chapter 3 - Nucleotides52
-
Chapter 3 - Ions11
-
Chapter 2 Basic components of living systems121
-
Chapter 2 - Prokaryotes vs Eukaryotes17
-
Chapter 3 - ATP17
-
Chapter 4 - Enzymes99
-
Chapter 5 -112
-
Chapter 6255
-
Chapter 7 - Exchange Surfaces135
-
Chapter 8172
-
Chapter 9 - Transport in plants180
-
Chapter 10 -119
-
Chapter 11 - Biodiversity195
-
Chapter 12 - Communicable Diseases301
-
Chapter 15 - Homeostasis96
-
Excretion84
-
Excretion - kidney123
-
Neuronal Communication135
-
Hormonal communication99
-
Plant and Animal Responses118
-
Plant responses38
-
Photosynthesis98
-
Respiration91
-
Cellular Control84
-
Patterns of Inheritance128
-
Manipulating genomes98
-
Cloning and Biotechnology144
