Topic 1- Lifestyle, Health And Risk Flashcards
What is cholesterol?
Cholesterol is a lipid found in the cell membrane which regulates fluidity.
What kind of structure does cholesterol have?
A steroid structure similar to testosterone and progesterone.
What is a lipoprotein?
A particles containing triglycerides and cholesterol surrounded by phospholipids and membrane.
What does LDL stand for?
Low density lipoprotein (bad cholesterol)
What does LDL do?
It transports cholesterol from the liver to tissues for the formation of membranes by binding to surface LDL receptors.
Why do high levels of LDL increase risk of atherosclerosis?
There are more LDL particles available than there are LDL receptors so LDL cholesterol cannot be removed from blood so more is deposited in blood vessels.
What is the difference between HDL and LDL structure?
HDL has unsaturated triglycerides whereas LDL has saturated.
What does HDL stand for?
High density lipoprotein (good cholesterol)
Why is HDL more dense?
Has a higher proportion of proteins than cholesterol
How does HDL reduce deposition of cholesterol in arteries?
By transporting it back to the liver for it to be destroyed.
What are the effects of saturated fats on cholesterol? (3)
- Increases LDL cholesterol
- Pushes HDL:LDL ratio in favour of LDL
- Reduces activity of LDL receptors so the cells are less able to remove LDL cholesterol from the blood
What is the solution to high blood cholesterol?
Replacing saturated fats with polyunsaturated fats which lower total blood cholesterol and decrease more LDL than HDL.
How much energy is once calorie worth?
The amount required to raise 1g of water by 1 degree Celsius
What do we need energy for? (7)
- Heart beat
- Digestion
- Movement
- Growth and repair
- Brain function
- Breathing
- Maintaining body temperature
What are the 8 factors that affect energy use?
- Temperature
- Exercise/ activity level
- Gender
- Illness/health
- Body composition
- Stress
- Age
- Pregnancy
Definition of basal metabolic rate?
Energy required to carry out basic functions to keep you alive.
What can the basal metabolic rate be affected by? (4)
- Age- older is less energy
- Weight- heavier is more
- Height- taller is more
- Biological gender
What happens when there is more energy in than out?
Excess energy is stored as fat and weight is gained
What happens when there is less energy in than out?
Body tissues is respired and weight is lost.
What does excessive weight gain lead to?
Obesity—> strains heart and circulatory system—-> increased risk of CVD
What are the 2 obesity indicators?
- BMI= weight (kg) divided by height2 (cm2). Doesn’t take into account body composition though so someone with high muscle mass may be wrongly deemed obese. >18 is underweight and 30+ is obese.
- Waist:hip ratio. Takes into account distribution of fat
What are the 5 things that overestimation of risk can be caused by?
- Media reports
- Overexposure to information
- Personal experience with risk or outcome
- Unfamiliarity
- The thing causes sever harm
What are the 6 things that can cause underestimation of risk?
- Lack of information
- Misunderstanding factors that increase risk
- Lack of personal experience
- Unfamiliarity
- Harm not being immediate
- Partaking in risk voluntarily
Definition of causation?
When the change in one variable causes a change in another.
What is an epidemiologist?
A scientist that studies patterns of disease.
What are the 2 risk factor studies?
Cohort and case control studies
What are cohort studies? (3)
- Are prospective which means no one starts with the disease.
- They follow large groups of people over a period of time and see who gets the disease
- Over this time, their exposure to risks are recorded and eventually correlations between risk factors and the diseases are made.
What is the evaluation of cohort studies? (2)
- Take many years
- Expensive
What are the 2 different types of cohort studies?
- One follows the general population and records the risks along the way.
- One uses 2 populations, one with a specific risk factor and the other without
What are case control studies? (3)
- They are retrospective which means that they look into the past
- They compare 2 groups of people, one with the disease and one without
- They then gather data on risk factors that they have been exposed to in the past and identify which risk factors contributed to the development of the disease.
What is the evaluation for case control studies? (2)
- Cheaper and faster
- Relies on reliable reporting from memory.
What are the 5 features of a good study?
- Good design
- Clear aim
- Must have large (1000+) and representative (non-biased) samples
- Must be valid- accurate measurements that measure what they claim to
- Must be reliable- collect same results when repeated.
What are the 9 risk factors for CVD?
- Smoking
- Age
- Genetics
- Gender
- Cholesterol levels
- Blood pressure
- Sedentary lifestyle
- Poor diet
- Stress
Why is smoking a risk factor for CVD?
It is addictive so hard to stop due to nicotine
Nicotine stimulates adrenaline production which:
1. Increases heart rate
2. Constricts arterioles
3. And both of these increase BP which is another risk factor.
It is also correlated with lower HDL
What are the other 2 chemicals in cigarettes?
- Tar/carcinogens:
- Damage artery walls so can lead to atherosclerosis - Carbon monoxide:
- Blocks oxygen from binding to haemoglobin which increases heart rate and blood pressure.
Why is age a risk factor for CVD? (3)
- Arteries become less elastic which causes blood pressure to increase
- You can drink when you are older which is another risk factor
- May be less able to exercise which increases risk
Why is genetics a risk factor for CVD? (2)
And what is the evaluation?
- Single gene inheritance e.g dominant allele for FH causes mutation in LDL receptor which decreases efficiency.
- Multiple genes cause most changes in risk e.g apolipoprotein genes A,B and E.
However, all these mutations are exacerbated or reduced by lifestyle choices.
So it is hard to determine the real effects of the mutations alone.
Why are cholesterol levels a risk factor for CVD? (2)
- High LDL levels increase risk
- Cholesterol forms part of an atheroma
Why is blood pressure a risk factor for CVD?
High blood pressure means damage to artery walls is more likely so there is a higher risk of atherosclerosis and atheromas.
It can also cause oedema which is swelling due to excess tissue fluid leaking from capillaries which then gets filtered by the lymph system.
What are the 4 factors that can elevate blood pressure?
- Stress
- Artery elasticity
- Weight
- High salt diet as water follows high salt concentration into the blood so the volume increase.
What are the 5 benefits to CVD of exercise?
- Prevents and can reduce high blood pressure
- Can help to maintain a healthy weight
- Increase levels of HDL without affecting LDL
- Increase chances of recovering from heart attack or stroke
- Increase efficiency of cardiovascular system and strength of heart muscle.
What are the 4 things included in poor diet?
- High salt levels
- can cause the kidney to retain water so increases blood pressure - Heavy alcohol consumption can:
- Increase blood pressure
- contributes to obesity
- can cause heart palpitations
- damages tissues like the brain, liver and heart
- Ethanol can end up in VLDL’s which increase risk of plaque formation. - No fruit or veg
- radicals are very reactive products made from chemical reactions in the body, antioxidants from vitamins in fruit and veg can help reduce them - Coffee
- Caffeine is a stimulant so increases heart rate and raises blood pressure
What is the benefit of moderate alcohol consumption?
Moderate consumption of red wine has been found to have a protective effect as correlations between increased HDL and red wine have been found.
Why is stress a risk factor of CVD?
Poor stress management has been linked to CVD.
It increases adrenaline which increases blood pressure
And can cause overeating, poor diet, drinking and smoking
What is the general formula for carbohydrates?
Cx(H20)n
What is the general formula for monosaccharides?
(CH20)n
What are 3 examples of monomers and 3 examples of polymers?
Amino acids, nucleotides, monosaccharides
DNA/RNA, polypeptide chains, polysaccharides
What reactions turn monomers into polymers and polymers back to monomers?
Condensation joins 2 monomers as water is produced and an OH +O is lost
Hydrolysis breaks down a polymer as water is lost and an OH+O is gained.
What bonds do amino acids have?
What bonds do nucleotides have?
What bonds do carbohydrates have?
- Peptide
- Phosphodiester
- Glycosidic
What are the 3 types of carbohydrates?
Monosaccharides, disaccharides, polysaccharides
What are monosaccharides, disaccharides and polysaccharides made of?
- One single sugar unit
- 2 sugar units joined by glycosidic bond
- Long chain of sugar units
What are the 3 characteristics of monosaccharides and how many carbons do they have?
They taste sweet, they’re water soluble and they are easily absorbed by cells.
They have 3-7 carbons
How does monosaccharide structure relate to their function in the body?
They are the main source of energy in plants and animals as their structure makes them soluble so they can be easily transported and their bonds hold a lot of energy so theyre used as a rapid source of energy.
What are the three characteristics of disaccharides?
They taste sweet, they are soluble but less than monosaccharides, their chemical bonds hold more energy than monosacs.
How are disaccharides used in the body?
They are too big to cross the cell membrane so have to be digested
What are the 3 main polysaccharides?
Starch and cellulose (plants) and glycogen (animals)
What are 3 main characteristics of polysaccharides?
Insoluble, compact, storage molecules
How are polysaccharides structure related to their role in the body?
They are insoluble so lots of glucose can be stored as glycogen as it doesn’t affect the water potential
What is starch broken down into?
Amylose which is an unbranched molecule with 1-4 glycosidic bonds between C1 OH and C4 OH. It is a linear shape but can coil into a spiral which makes it more compact so good storage molecule. Made up of 200-5000 glucose monomers, makes up 20-30% of starch.
Amylopectin which is a branched molecule so it has more surface area for enzymes to react with it and break it down faster. This means it is joined by 1-4 glycosidic bonds and also 1-6 glycosidic bonds.
What are the 4 characteristics of glycogen?
It is a polysaccharide of alpha glucose
Joined by 1-4 and 1-6 glycosidic bonds
Has more branches than amylopectin.
Very compact
What are 2 examples of lipids?
Triglycerides and cholesterol
Are triglycerides more or less energy dense than carbohydrates?
More as they are 37kj/g and carbs are 16kj/g
What are triglycerides made up of and what bonds?
Made up of one glycerol and three fatty acids which are palmitic acid. They are joined by ester bonds.
Are triglycerides saturated or unsaturated?
They are saturated as they have no double carbon carbon bonds.
Where can saturated fats be found and what is the melting point like?
They can be found in animal fats and the melting point is high as the fatty acid chains are packed tightly together.
What are the features of the fatty acid tails?
They are hydrocarbons and they are hydrophobic which means lipids are not water soluble
What are unsaturated lipids and what is an example?
They are fatty acids with at least one double carbon carbon bond and an example is oleic acid.
What state are unsaturated lipids at room temperature and why?
They are liquid at room temperature as the double carbon bonds causes their fatty acid tails to be kinked and therefore less tightly packed.
What are monounsaturated and polyunsaturated lipids?
What is a hydrogenated fat?
- Lipids with one double carbon bond
- Lipids with 2 or more double carbon bonds
- An unsaturated lipid made saturated by the addition of hydrogen.
What 5 things does an open circulatory system have?
- Fluid bathes all cells
- Heart beats to pump fluid around cells
- No blood vessels
- Only works in small animals
- Only works in cold blooded animals as they have a lower metabolic rate.
What 3 things does a closed circulatory system have?
- Has blood vessels
- Blood is confined to blood vessels
- One directional flow
What 3 things does a double circulatory system have?
- Blood passes through heart twice per cycle
- Higher blood pressure and mass flow
- More efficient oxygen delivery and waste removal
What 4 things does a single circulatory system have?
- Blood passes through heart once per cycle
- Lower blood pressure and mass flow
- More efficient diffusion from gills as oxygen concentration is lower in water
- Cannot support a high metabolic rate
What does mass flow mean?
What does mass transport system do?
- Movement of transport mediums via change in pressure like the heart for the blood.
- Moves lots of substances quickly
What does dipole mean?
What is a polar molecule?
- The difference in charge across a molecule
- A molecule with a dipole nature
What do cohesion and adhesion mean?
- When water sticks to other surfaces
- When water sticks to itself like in the xylem
In water, which molecules are slightly positive and which are slightly negative?
The oxygen is slightly negative and the hydrogens are slightly positive
Why can water easily transport all sorts of substances?
Because it is a solvent and a liquid. It can also dissolve polar molecules like carbs and proteins and charged ions like Na and Cl as it forms a shell around them due to its dipole nature.
What causes cohesion and adhesion?
The slightly negative H is attracted to a slightly negative O on another molecule so forms a hydrogen bond.
Why does water have such a high specific heat capacity?
Because it is held together by covalent bonds which take a lot of energy to break.
What are the 7 things it does and is useful in?
- Reactant in cells e.g photosynthesis and hydrolysis
- Provides structural support in cells
- Keeps organisms cool to maintain optimum temperature
- Has a high specific heat capacity so heats quickly and cools slowly
- Useful as a solvent
- Has cohesive properties which allows it to flow
- Has metabolic importance
What is collagen?
Collagen is a fibrous protein which provides a strong and flexible layer around the outside of arteries and veins.
What is the structure of an artery? (4)
- Collagen
- Thick layer of muscle and elastic fibres to allow recoil of artery following a pulse to maintain high blood pressure.
- Folded endothelium to allow lumen to stretch and smooth to prevent blood from slowing.
- Narrow lumen to maintain high blood pressure
What is the structure of a vein (5)?
- Collagen
- Muscle and elastic fibres to allow stretch and thinner as blood is at a lower pressure
- Smooth endothelium to allow low pressure blood to flow easily
- Wide lumen to allow low pressure blood to flow easily.
- Valves to prevent backflow and contraction of body muscle helps flow of blood.
What is the structure of a capillary (3)?
- Only one cell thick of endothelium to reduce diffusion distance
- Gaps in cells to allow WBC’s and plasma to pass through
- There are millions of them so large SA
What is definition of systole and diastole?
Systole= heart is contracting
Diastole= heart is relaxing
What is atherosclerosis?
The formation of fatty plaques (atheromas) in arteries and the hardening of arteries (sclerosis).
What are the 4 stages of atherosclerosis?
- Damage to endothelium. High blood pressure increases the risk of damage and so does toxins from cigarette smoke.
- Inflammatory response. WBC’s are recruited to the site of damage and use cholesterol to form a fatty plug (atheroma).
- Plaque formation. There is a build up of calcium salts, fibrous proteins and cholesterol which hardens and reduces the elasticity of the artery (sclerosis). This blocks part of the artery and narrows it.
- Positive feedback loop. Because the artery has been narrowed, this increases blood pressure which increases risk of more damage to endothelium and the cycle repeats.
Why does atherosclerosis happen in arteries rather than veins?
Because arterial pressure is higher than venular.
What is clotting?
Clotting is the recruitment of platelets to the site of damage e.g a cut caused by a plaque breaking off.
What are the 6 steps of the clotting process?
- Platelets are recruited to the site of damage.
- Platelets become sticky and form a fatty plug
- Cascade of chemical changes begins.
- Thromboplastin is released which converts prothrombin (protein) into thrombin (enzyme).
- Thrombin converts fibrinogen (soluble plasma protein) into fibrin (insoluble).
- Fibrin mesh forms which traps RBC’s and platelets and clot forms.
What are 4 effects of atheromas and clots?
- The narrowing of the coronary artery caused by atheromas, prevents blood flow and oxygen to the heart muscle.
- The heart muscle cannot get enough oxygen so begins respiring anaerobically which leads to a build up of lactic acid and angina. Angina is usually experienced during exertion when the heart has to beat harder and faster.
- Fatty plaque breaks off which leaves collagen exposed so rapid clot formation takes place. This blocks supply of blood and oxygen to the heart which causes it to become ischaemic and cells may be permanently damaged.
- Heart muscle begins to die which causes a myocardial infarction and if blood flow to the brain is interrupted a stroke is caused and tissue becomes ischaemic and begins to die.
What is needed in the blood for thromboplastin to convert prothrombin into thrombin?
Vitamin K and calcium ions.
What are the 2 obesity indicators?
BMI and waist to hip ratio
