1
Q
2 functions of water
A
- Water is a solvent, substances dissolve in it, and most biological reactions take place in a solution
- Water transports substances, some can be transported more easily if they are dissolved in a solvent, so water being a liquid and solvent means it can easily transport all sorts of materials e.g. glucose and oxygen around plants and animals
2
Q
What and how many of these atoms do water molecules consist of
A
A molecule of water is: one atom of oxygen joined to two atoms of hydrogen by shared electrons
3
Q
Describe the polarity of water
A
Water is a polar molecule due to unevenly distributed negative charge
Because the shared negative hydrogen electrons are pulled towards the oxygen atom, the other side of each hydrogen atom is left with a slight positive charge
The unshared negative electrons on the oxygen atom give it a slight negative charge
This makes water a dipolar molecule - it has partial negative charge on one side and a partial positive charge on the other
4
Q
Describe the hydrogen bonding in water
A
The slightly negatively charged oxygen atoms attract the slightly positively charged hydrogen atoms of other water molecules
This attraction is called hydrogen bonding and gives water some of its useful properties e.g. liquid at room temperature
Hydrogen bonding is weak but as there are so many bonds it takes a lot of energy to break these
5
Q
Properties of water - cohesion
A
Cohesion is the attraction between molecules of the same type (e.g. two water molecules)
Water molecules are very cohesive (tend to stick together because they’re dipolar
This helps water flow, making it great for transporting substances
6
Q
Properties of water - good solvent
A
Many substances in biological reactions are ionic
Made from one positively charged atom/molecule and one negatively charged atom/molecule (e.g. salt - positive sodium ion and negative chloride ion)
Because water is dipolar the slightly positive end of a water molecule will be attracted to the negative ion and vice versa
Ions will get totally surrounded by water molecules - they will dissolve
Water’s dipole nature makes it useful as a solvent in living organisms e.g. in humans, important ions can dissolve in blood and then be transported around the body
7
Q
Other properties of water
A
1 .Liquid at room temperature
Water is polar, allowing it to form hydrogen bonds which allow water to remain liquid at room temperature, creates cohesion and adhesion enabling effective transport
- Low density as a solid
Habitat for organisms
Insulates water below, another habitat - High surface tension
- Good solvent
- High specific heat capacity
High as large amount of energy required to break hydrogen bonds, water warms up and cools down slow
Useful for organism, help them avoid rapid changes in internal temperature even if surroundings vary considerably
Bodies of water which aquatic organisms live do not change temperature rapidly
When heating, the heat energy goes towards weakening/breaking bonds rather than increasing kinetic energy of water molecules - High latent heat of vaporisation
8
Q
Functions of a heart
which side pumps what blood
A
It pumps blood around the body to deliver oxygen and glucose to cells for aerobic respiration
It removes waste such as carbon dioxide and urea
The right side of the heart pumps deoxygenated blood to the lungs
The left side pumps oxygenated blood to the rest of the body
9
Q
Functions of semi lumnar valves
A
The semilunar valves permit blood to flow into the arteries (aorta and pulmonary artery) from the ventricles and prevent backflow of blood
Valves in the heart open when the pressure of blood behind them is greater than the pressure of blood in front of them
Valves in the heart close when the pressure of blood in front of them is greater than the pressure of blood behind them
10
Q
Label features of the heart
A
Vena cava –> right atrium –> AV valve –> right ventricle –> SL valve –> pulmonary artery –> lungs –> pulmonary vein –> left atrium –> AV valve –> left ventricle –> SL valve –> aorta –> body
11
Q
Functions of chordae tendanae
A
The chordae tendineae are made of non-elastic tissue (do not stretch) and attach the valves to the ventricle walls (via papillary muscles) and prevent AV valves of the heart from movement and from inverting by holding flaps tightly in place
12
Q
Functions of the papillary muscle
A
The papillary muscles pull the chordae tendineae taut and prevents valves from opening when ventricles contract, muscles contract and relax which is simultaneous ot the pulls and release on the the strings
13
Q
Functions of AV valves
A
The atrioventricular valves open during diastole and close during systole, directing blood through the semilunar valves to the body
14
Q
Function of the myocardium
A
The myocardium contains cardiac cells that expand and contract in response to electrical impulses from the nervous system
15
Q
Function of septum
A
The interventricular septum stops oxygenated and deoxygenated blood mixing
16
Q
Function of SA node
A
The SA node contains special cells which generate electrical impulses which initiate heartbeat and cause atria to contract
17
Q
Function of AV node
A
The AV node detects impulses from the SA node and causes ventricles to contract
18
Q
Function of coronary arteries
A
Coronary arteries supply oxygen and glucose to the heart for muscle contraction
19
Q
The hearts adaptations
A
- The muscular wall of the left ventricle is much thicker than that of the right ventricle because the left ventricle has to pump blood a further distance to the body whilst the right only pumps blood to the lungs which is a shorter distance
- The ventricles have thicker walls than the atria because they have to push blood out of the heart whereas the atria have to push blood a short distance to the ventricles
- The AV valves link the atria to the ventricles and stop blood flowing back into the atria when the ventricles contract
- Cords attach the AV valves to the ventricles to stop them being forced up the atria when ventricles contract - The semilunar valves link the ventricles to the aorta and pulmonary artery, and stop blood flowing back into the heart after the ventricles contract
20
Q
What is the difference between a smaller and larger organism
A
As an organism gets bigger and more multicellular they cannot rely on simple diffusion due to a much smaller SA/V ratio
Therefore you need a specialised exchange system to allow for a rapid rate of diffusion
21
Q
What is mass transport
A
Mass transport is the bulk movement of gases or liquids in one direction, usually via a system of vessels or tubes
22
Q
Function of mass transport
A
- Bring substances quickly from one exchange site to another
- Maintain diffusion gradients at exchange sites and between cells and their fluid surroundings
- Ensure effective cell activity by supplying reactants and moving waste products
23
Q
Function of a mass transport system
A
A mass transport system moves raw materials (e.g. glucose and oxygen) from specialised exchange organs (e.g. lungs and digestive system) to body cells and removes metabolic waste (e.g. carbon dioxide)
In mammals the mass transport system is the circulatory system
24
Q
How do substances move in a mass transport system
A
These substances move by flow mass
All of the substances in a liquid move together in one direction as a result of differences in pressure (pressure gradient)
Mass flow of a liquid maintains a steep concentration gradient
25
What is an open circulatory system
Blood is not contained within vessels
In insects and some other animal groups, blood circulates in large open spaces
A simple heart pumps out blood into cavities surrounding the animals organs and drawn back in making blood flow really slow
Substances can diffuse between the blood and cells
26
What is a closed circulatory system
Many animals have a closed circulatory system in which the blood is enclosed within tubes - blood is transported through vessels
Directing blood flow to specific parts of the body
This generates higher blood pressure as the blood is forced along fairly narrow channels instead of flowing into large cavities
This means that blood flow is fast and so the blood system is more efficient at delivering substances around the body
27
What is a single circulatory system
Blood flows through the heart once for each complete circuit of the body
28
What is a double circulatory system
This means that the blood flows through the heart twice for each complete circuit of the body
29
Describe a double circulatory system
1. The right ventricle of the heart pumps deoxygenated blood to the lungs where it receives oxygen
2. The oxygenated blood then returns to the heart to be pumped a second time (by the left ventricle) out to the rest of the body
30
Function of blood vessels
1. Maintain pressure
2. Allow blood to be supplied to different parts of the body
3. Directs blood flow to specific parts of the body
31
How does the single circulatory system of a fish work
1. The heart pumps deoxygenated blood to the gills
2. Gaseous exchange takes place in the gills; there is diffusion of carbon dioxide from the blood into the water that surrounds the gills and diffusion of oxygen from this water into the blood within the gills
3. The blood leaving the gills then flows round the rest of the body before eventually returning to the heart
32
Structure and function of arteries
Tough outer layer containing collagen - resists high pressure and provides high tensile strength which avoids rupture
Thick smooth muscle layer - can contract and control the flow of blood by constricting the lumen
Thick elastic layer - can stretch and recoil to maintain blood pressure and protect the walls of the arteries from damage by withstanding high pressure
Folded endothelium - smooth layer reduces friction during blood flow preventing clots
Small relative lumen - maintains blood pressure
No valves as pressure from heart is so strong blood is only able to flow in one direction
33
Structure and function of veins
Thin smooth layer of muscle - blood flows slowly and in large volumes so less need to control the flow
Thin elastic layer - low pressure blood requires less maintenance and is less likely to damage walls
Smooth endothelium - prevents backflow of low pressure and slow flowing blood
Wide lumen minimises resistance to flow
Valves to prevent backflow of slow flowing blood
34
What are the benefits and risk of statins?
BENEFITS: reduce levels of LDLs so reduce atheroma development, increase levels of HDLs
RISKS: can take a while to be effective, must be taken long term, side effects include muscle and joint pain, liver damage and neurological issues, gives patients a false sense of security
35
What does systole and diastole mean
Systole means contraction
Diastole means relaxation
- Normally diastole is longer than systole
36
Stage 1. Ventricular diastole, atrial systole
The ventricles are relaxed, the walls of the atria contract
-Atrial volume decreases
-Atrial pressure increases
The pressure in the atria rise above those in the ventricles, forcing the atrioventricular valves open
Blood is forced into the ventricles
-There is a slight increase in ventricular pressure and chamber volume as the ventricles receive blood from the atria
The ventricles are relaxed at this point
37
Stage 2. Ventricular systole , atrial diastole
The atria are relaxed, walls of the ventricles contract
-The ventricular volume decreases
-The ventricular pressure increases
The pressure in the ventricles rises above that in the atria
-This forces the atrioventricular valves to close, preventing backflow of blood
The pressure in the ventricles rise above that of the aorta and pulmonary artery
-This forces semilunar valves to open so blood is forced into the arteries and out of the heart
The blood flow to the heart continues, the relaxed atria begin to fill up with blood again
38
Stage 3. Cardiac diastole
The ventricles and atria are both relaxed
Elastic recoil as the heart relaxes causes low pressure in the heart, helping to refill the chambers with blood from the veins
The pressure in the ventricles drop below that in the aorta and pulmonary artery, forcing the semilunar valves closed
The atria continue to fill with blood
-Blood returns to the heart via the vena cava and pulmonary vein
Pressure in the atria rises above that in the ventricles, forcing the atrioventricular valves open
Blood flows passively into the ventricles without need of atrial systole
The cycle then begins again with atrial systole
39
All living organisms respire by...
taking in oxygen and giving out carbon dioxide
These gases diffuse across the gas exchange surface
40
Structure and function of capillaries
No muscle
No elastic
No valves
Thin layer of endothelium cells
One cell thick walls - short diffusion distance
Numerous and highly branched - large SA for diffusion
Narrow diameter -keeps all the cells close by
Narrow lumen - brings RBC (only allows one at a time) close to cells = short diffusion distance
Spaces between cells - allows WBC to escape
41
What is the cardiac cycle
The cardiac cycle is an ongoing sequence of contraction (systole) and relaxation (diastole) of the atria and ventricles that keeps blood continuously circulating around the body
42
What is the exchange surface in unicellular organisms
the whole cell surface membrane
43
Why do larger organisms have to do more exchange
to meet organisms metabolic needs
-Larger organism have more problem absorbing substances because of their smaller surface area to volume ratio
-Relying on only the outer body surface for gas exchange is only possible for organisms with a very small volume, or in larger organisms that have a high enough SA:V, e.g. worms with a tubular or flattened shape
44
So how have larger organisms adapted to have effective gas exchange
Larger organisms have a variety of special organs that have evolved to:
Increase the surface area for exchange, increasing surfaces area to volume ratio
→ E.g. alveoli provide a large surface area
Thin (often one layer of epithelial cells) providing a short diffusion pathway
These organisms also maintain a steep concentration gradient of gases
45
What are lipoproteins
spherical complexes consisting of
-An outer layer of phospholipids, studded with proteins
-An inner core of triglycerides and cholesterol
46
What are the two major types of lipoproteins
low-density lipoproteins (LDL) and high-density lipoproteins (HDL)
47
What is the function of LDL's
transport cholesterol from the liver to body tissues, depositing it on the walls of blood vessels. In high levels it contributes to atherosclerosis
48
What is the function of HDL's
transport cholesterol (excess LDL) away from the tissues to the liver, where cholesterol is metabolized
49
What is an atheroma/plaque
A build up of fatty deposits, mainly LDL cholesterol which forms within the endothelium of an artery
50
What does an endothelium look like in a healthy artery
smooth and unbroken to reduce friction between blood and the inside of the artery
51
What happens if a blood supply is blocked completely
-In coronary arteries this results in a heart attack (myocardial infarction)
-In the arteries supplying the brain this results in a stroke
-The supply of blood to the brain is restricted or blocked, causing damage or death to cells in the brain
-Narrowing of arteries to the legs can result in tissue death or decay
-An artery can burst where blood builds up behind an artery that has been narrowed as a result of atherosclerosis
52
6 steps of atherosclerosis
(Atherosclerosis can be triggered by a number of factors, whatever the trigger, this is the course of events that follow)
1. The endothelium (delicate layer of cells lining the inside of an artery and separates the blood that flows along the artery from the muscular wall) becomes damaged or dysfunctional
2. Once the inner lining of the artery is breached there is an inflammatory response where white blood cells such as macrophages accumulate in the damaged area
3. These cells ingest LDL cholesterol that has entered the arterial wall, forming foam cells which accumulate to form fatty streaks under the endothelium
4. Calcium salts and fibrous tissue also build up around the streaks forming a plaque on the inner wall of the artery
-The build up of fibrous tissue means the wall hardens and loses elasticity
5. The plaque also narrows the lumen restricting blood flow and further increasing blood pressure
6. This process is self perpetuating - dangerous positive feedback is building up, plaque leads to high blood pressure and this makes it more likely that further plaques will form, as damage to other endothelial tissues becomes more likely
53
What are possible risks of cardiovascular disease
1. High saturated fat diet - Increases blood cholesterol level which increases atheroma formation leading to the formation of blood clots which leads to heart attack, strokes or DVT
A diet high in salt also increases blood pressure
High blood pressure
-Increases risk of damage to arterial walls increasing risk of atheroma formation which can lead to CVD
-Excessive alcohol consumption, stress and diet can also increase blood pressure
Physical inactivity
-A lack of exercise increases the risk of CVD because it increases blood pressure
Type 1 diabetes
Obesity
54
How is smoking a risk of cardiovascular disease
Smoking
-Carbon monoxide in cigarette smoke combines with hemoglobin (the protein that carries oxygen in the blood) and reduces the amount of oxygen transported in the blood
-This reduces the amount of oxygen available to tissues
If the heart does not receive enough oxygen it will cause a heart attack and if the brain does not receive enough oxygen it will have a stroke
-Nicotine in cigarette smoke makes platelets sticky which increases the chance of blood clots forming, increasing the risk of CVD
-Smoking also decreases the amount of antioxidants in the blood - these are important for protecting cells from damage
-Fewer antioxidants means cell damage in artery walls is more likely and this can lead to an atheroma formation, increasing the risk of CVD
55
Factors beyond control that are risks to CVD
Genetics
Some people inherit particular alleles that make them more likely to have high blood pressure or high blood cholesterol so they are more likely to suffer from CVD
Age
The risk of developing CVD increases with age
Partly because plaque can build up slowly over time eventually leading to CVD
Gender
Men are three times more likely to suffer from CVD than pre-menopausal women
This may be due to their different levels of hormones e.g. oestrogen increases amount of good cholesterol
The relatively low level of this hormone in men leads to higher levels of total blood cholesterol and increases the risk of CVD
56
Explain how an atheroma can lead to a dead heart muscle
The coronary artery supplies heart muscle cells with oxygen and glucose, if blocked then the supply will be reduced or stopped completely. The muscle cells will die due to lack of aerobic respiration. Anaerobic respiration will occur leading to a build up of lactic acid where reduced pH denatures enzymes and also kills muscle cells
57
Why is there less risk of damage to walls in veins
Low blood pressure
58
Functions of blood clots
prevents excess blood loss, the entry of pathogens, and provides a barrier, or scab under which healing would occur
59
How do platelets change structure when in contact with a damaged vessel
When platelets (no nucleus) come in contact with damaged vessel wall they change from flattened discs to spheres with long thin projections
Their cell surfaces change, causing them to stick to the exposed collagen in the wall and to each other to form a temporary platelet plug
They also release substances that activate more platelets
60
The clotting process (before the cascade)
1. When a blood vessel is damaged, the endothelial lining is broken, exposing collagen fibers in artery wall
2. Platelets in blood come in contact with exposed collagen, activating the platelets (change shape and stick to damaged area and together)
61
The clotting cascade
3. The active platelets initiate the release of clotting factors such as thromboplastin, calcium and vitamin K which triggers the clotting cascade
4. These clotting factors activate an inactive plasma protein called prothrombin
5. Prothrombin is converted into an enzyme called thrombin
6. Thrombin catalyses the conversion of soluble plasma protein fibrinogen into insoluble threads of fibrin which covers the wound in mesh, trapping red blood cells and platelets - creating a clot
7. The fibrin mesh strengthens and stabilises the clot forming a seal over the wound to prevent further blood loss and reduce risk of infection
62
What is coronary heart disease
when coronary arteries have a lot of atheromas in them restricting blood flow in arteries and also increasing risk of blood clots forming leading to an increased risk in heart attack
63
What is the definition of a risk
Risks can be defined as the chance of an unwanted event/outcome occurring e.g. if you smoke you increase your chance of developing CVD
64
Why may people overestimate risks
People overestimate risks possibly due to factors such as
-Misleading information in the media
-Overexposure to information
-Personal experience of associated risk
-Unfamiliarity to the event
-The event causing severe harm
65
Risks may be underestimated because of factors such as
-Lack of information
-Misunderstanding of factors that increase risk
-A lack of personal experience of the associated risk
-Unfamiliarity with the event
-The harm being non immediate
66
Why do people underestimate risks
This might be because
-May be unwilling to change their lifestyle
-The risk is seen as being in the future and will not affect them now
-No family history of heart disease may give them a false sense of security
-Women may perceive the disease as only affecting men
-Lifestyle choices are under our control
-The perceived benefits of certain lifestyles may outweigh the risks
-Some factors are not able to be controlled, so they may believe there is nothing they can do
-People trust in medicine to help them should they develop CVD
67
Correlation meaning
Correlation - a link between or relationship between two factors
68
Causation meaning
Causation - a change in factor results in a change in the other factor
69
What do you need to claim a causation
In science, in order to claim a causation, there must be a scientific mechanism
A causal link
70
Why do you have to do multiple studies to conclude a causation risk factor
-Evidence from one study alone is not enough to to conclude a causation risk factor
-Similar studies would have to be carried out and the results peer reviewed
-If these came to the same conclusion, the conclusion would be increasingly accepted amongst the scientific community
-Sometimes studies come up with conflicting evidence so further research would have to be conducted before it is accepted
71
What makes a good scientific study
1. Large sample size (100 at least) - more reliable
2. Representative (should reflect a variety of characteristics) - generalisable
3. Controlled variables - more valid
4. Data collection - precise apparatus, reduces bias, gives more accurate results
5. Control tests - increases validity as it enables comparisons
6. Repetition by other scientists
72
What does an overlap in standard deviation error bars mean
There is NO significant difference between two variables
73
Examples of CVD treatments
Antihypertensives
Statins
Anticoagulants
Platelet inhibitors
74
What do antihyperintensives do
Antihypertensives - lower blood pressure → reduces risk of endothelial arterial damage → reduces risk of atheromas and thrombosis
Beta Blockers = prevent increase in heart rate
Vasodilators = increase diameter of blood vessels
Diuretics = decrease sodium reabsorbed into blood by kidneys, therefore decreasing the volume of water being reabsorbed
75
What do statins do
lower blood cholesterol → blocks an enzyme in the liver --> lowers LDL concentration → reducing risk of atheroma formation
76
What do anticoagulants do
reduce blood clotting → decreases likelihood of thrombosis → reduces risk of blood vessels being blocked by blood clots
blocks synthesis of clotting factors
77
What do platelet inhibitors do
reduce blood clotting → prevent clumping of platelets by preventing platelets from becoming activated/sticky e.g. aspirin
78
What do carbohydrate molecules consist of
carbon, hydrogen and oxygen
79
What is their function
They provide and store energy in plants and animals
80
What are the 3 types of carbohydrates
monosaccharides, disaccharides & polysaccharides
81
What are monosaccharides
Monosaccharides are single sugar units used as building blocks for more complex carbs
Most carbohydrates are polymers composed of long chains of monosaccharides
82
functions of monosaccharides
-Form disaccharides and polysaccharides by glycosidic bonds which are formed in condensation reactions
-Provide rapid source of energy
-Readily absorbed
-Require little change before being used in cellular respiration
-Soluble so can be transported easily
-Lots of covalent bonds
83
How are monosaccharides joined together
by glycosidic bonds in a condensation reaction (a reaction where a molecule of water is released)
84
Explain what occurs in a condensation reaction of 2 monosaccharides
A hydrogen atom on one monosaccharide bonds to a hydroxyl (OH) group, releasing a molecule of water
Forms a disaccharide (soluble but not as soluble as monosaccharides and their chemical bonds store more energy than monosaccharides)
85
Structure of an alpha glucose
86
3 monosaccharide equations to form disaccharides
Glucose + glucose → maltose (1-4 glycosidic bond)
Glucose + fructose → sucrose (1-4 glycosidic bond)
Glucose + galactose → lactose (1-2 glycosidic bond)
87
What is a disaccharide
Two simples sugar units can join together and form a disaccharide in a condensation reaction releasing a water molecule as the two sugar molecules combine
88
What is the bond that forms between two sugar units
glycosidic bond
H + OH = H20
89
How can you split a glycosidic bond
The bond can be split by hydrolysis - add water to the bond and the molecule splits in two
Hydrolysis occurs when carbohydrates are digested into the gut and when carbohydrate stores in a cell are broken down to release sugars
90
What is a polysaccharide
Polysaccharides form when more than two monosaccharides join together
91
3 main polysaccharides found in food
starch, cellulose in plants and glycogen in animals
92
What is starch
Starch is the main energy source in plants - glucose produced in photosynthesis is joined together to form starch
Plants get energy from glucose, they store excess glucose as starch (and when needed, it breaks down more starch for energy)
Starch consists of a mix of amylose and amylopectin
93
Amylose structure and function
long unbranched chain of glucose joined together with 1,4 glycosidic bonds
The angles of the glycosidic bonds give it a coiled and compact structure - more compact than amylopectin
Good for storage as you can fit more in a tight space
94
Amylopectin structure and function
Long branched chain of glucose that contains 1,4 and 1,6 glycosidic bonds
Branches result in many terminal glucose molecules resulting in easy hydrolysing meaning glucose can be released quickly for use during cellular respiration
95
Starch features
insoluble in water, so it doesn't cause water to enter the cells by osmosis which would make them swell, making them good for storage
Insoluble - no osmotic effect
Compact - large quantities can be stored
96
What is glycogen
main energy storage in animals
97
Function and structure of glycogen
Insoluble - no osmotic effect
Compact - large quantities can be stored
Animals get energy from glucose but store it as glycogen - another polysaccharide of alpha-glucose
Similar structure to amylopectin (1,4 and 1,6 glycosidic bonds), except that it has loads more side branches coming off it
Lots of branches mean that stored glucose can be released quickly which is important for energy release in animals/suits the demands of the cell
Insoluble in water, does not cause cells to swell by osmosis
It is a large molecule so it can store lots of energy
98
What are lipids
Macromolecules that contain carbon, hydrogen and oxygen. Unlike carbohydrates they contain a lower proportion of oxygen
99
What are the roles and properties of lipids?
ROLES = energy yield, energy storage, insulation and hormonal communication
PROPERTIES = non polar and hydrophobic
100
What monomers form triglycerides?
Glycerol
101
What is a triglyceride?
Triglycerides are made up of 3 fatty acids and one glycerol molecule linked by condensation reactions
102
What bond links each fatty acid and the glycerol?
Ester bond
Three ester bonds in a triglyceride formed from glycerol and three fatty acids
The ester bond is the jointment O–C
103
What are the properties of fatty acid tails?
long tails made of hydrocarbons (carbon chains with hydrogen atoms branching off)
The tails are hydrophobic
These tails make lipids insoluble in water
Fatty acid tails consists of COOH (carboxyl group) joined to a long hydrocarbon chain - carbon and hydrogen
104
Which molecules do ester bonds form on
A hydrogen atom on the glycerol molecule bonds to a hydroxyl (OH) group on the fatty acid, releasing a molecule of water
105
What are the properties of saturated fatty acids?
They have no double bonds in the hydrocarbon tail, straight (unbranched, linear) chains,
ability to pack together tightly,
strong intermolecular forces,
SOLID at room temp due to high melting point
106
What are monounsaturated fats
Monounsaturated fats have one double bond between two of the carbon atoms in each fatty acid chain
107
What are polyunsaturated fats
larger number of double bonds
108
Properties of unsaturated fatty acids
Have one or more C=C double bond in hydrocarbon tail, kinked structure therefore cannot pack together tightly,
weaker intermolecular forces,
LIQUID at room temp due to low melting point
109
What is the difference between monounsaturated fats and polyunsaturated fats?
Monounsaturated fats have one C=C double bond, polyunsaturated fats have 2 or more
110
What are the benefits and risks of anti-hypertensives?
BENEFITS: reduce blood pressure, which can be monitored at home
RISKS: side effects include headaches, drowsiness, heart palpitations, patients may stop taking medicines due to the side effects
111
What are the benefits and risks of anticoagulants?
BENEFITS: reduce formation of blood clots, and reduce size and growth of existing blood clots
RISKS: can cause excessive bleeding if injury occurs, side effects include osteoporosis and fainting, can damage foetus
112
What are the benefits and risks of platelet inhibitors?
BENEFITS: reduces formation of new blood clots
RISKS: can cause excessive bleeding if injury occurs, side effects include rashes, liver dysfunction and stomach lining damage
113
How can unsaturated fats be made more solid at room temp?
Adding hydrogen to the bonds, making them saturated (hydrogenation)
114
What is cholesterol, and what do cells require it for?
A short lipid molecule produced in the liver
Required for: cell membrane functioning, sex hormone structure, synthesis of bile
115
How can you reduce risk factors of CVD?
Diet - decrease proportion of saturated fats
Obesity - lifestyle choices to reduce weight to healthy range
Smoking - health warnings on cigarette packages, TV and media portray as unhealthy lifestyle choice
Exercise - increased hours of PE at school, targeted encouragement to reduce inactivity
116
How is obesity measured?
BMI
Waist to Hip ratio
117
What is BMI?
BMI = body mass index
a conventionally used method of classifying body weight relative to a person’s height
BMI = body mass in kg/height in m ^2
118
What is waist to hip ratio?
Ratio of waist size to hip size
Found by dividing waist circumference by hip circumference
119
Which type of lipoprotein is associated with atherosclerosis?
LDLs
They create high blood cholesterol levels, which can be deposited in artery walls, forming atheromas
120
Whats the energy budget equation
Energy budget = energy input - energy output
121
What is a causal relationship?
Where a change in one variable directly causes a change in another
122
What is the function of disaccharides?
To provide the body with a quick release source of energy as they are easily broken down by enzymes and absorbed into the bloodstream
123
Why does eating complex carbohydrates not cause the swings in blood sugar seen after eating monosaccharides?
Complex carbohydrates (polysaccharides and disaccharides) have to be digested into monosaccharides before being absorbed, which takes some time
124
What is the function of monosaccharides?
To store energy within their bonds, so when broken during respiration, energy is released
They are rapidly absorbed and require little, or in the case of glucose, no change before being used in cellular respiration
125
Why should energy budgets be balanced?
If energy intake is higher than the energy output excess energy will be converted into fats by the body so the person will gain weight
If energy intake is less than energy output the body will need to take energy from elsewhere and fat reserves will be converted into energy, the person will lose weight
126
What is an energy budget?
The amount of energy taken in by an organism minus the amount of energy the organism transfers during life processes
127
How can a blood clot in an artery leading to the brain cause a stroke?
Reduced blood flow due to clot means oxygen/glucose will not reach cells in brain. Therefore there is no aerobic respiration and no ATP produced. The brain needs lots of ATP to function, so lactic acid is produced from anaerobic respiration which inhibits enzymes and is toxic
128
What is a platelet?
A cell fragment that releases thromboplastin
129
What is fibrinogen?
A soluble plasma protein
130
How can the location of an atheroma result in the position and size of dead heart muscle?
If the atheroma is located near the end of an artery, a much smaller region will be impacted.
131
How can atheromas increase the risk of blood clotting?
The plaque deposit from atheromas can rupture through the endothelium, triggering thrombosis
132
What is atherosclerosis?
The hardening of the arteries due to damage of the endothelium of an artery
