biological molecules to immune system Flashcards
Carbohydrates
- CHO (molecules)
Complex carbohydrates:
- Starch – energy stored in plants
- Glycogen – a similar structure to starch; energy stored in animals and fungi (in liver and muscles)
- Cellulose – plant cell walls
Simple sugars:
- Glucose – found in most things
- Fructose – found in fruits
Disaccharides:
- Lactose (milk)
- Sucrose (white sugar)
Proteins
Proteins:
- CHON(S) sometimes with sulfur
- Building blocks
- To grow, repair damaged tissues
- Large protein molecules are made from small molecules called animo acid
in red meats
Lipids
Lipids:
- CHO
- Long-term source of energy
- Oils (plants)/Fats (animals) ->liquid/solid at room temperature
- Formed by reaction of glycerol and fatty acids
Benedict test
- Benedict test for reducing sugars
- Turns brick red if there are large amount of them
- Orange (moderate)
- Green or yellow (traces)
- Blue (no sugar)
- Requires high temperature (boiling water)
Biuret test
- Biuret test for protein
- Turns violet if present
- Blue is negative
- Ethanol emulsion test
- Ethanol emulsion test
- White, milky fat or oil is present
- No colour change is not present
Enzymes
-> enzymes are biological catalysts (substance that increases the rate of a reaction) involved in all metabolic reactions. They speed up reactions without being used up or changed in the process.
Enzyme catalysed reactions
- The substrate fits into the part of the enzyme with a complementary shape, the active site.
- The reaction happens.
- The products of the reaction detach from the enzyme’s active site
Denaturation
When the temperature is too high or the pH gets too high or too low, the shape active site changes; they are no longer complementary, and reactions cannot take place. The enzyme is now denatured and no longer functions. This change is usually permanent and cannot be reversed.
Pepsin and salivary amylase pH
2 and 7
Why does increasing temperature affect enzyme activity
As the temperature increases, particles gain kinetic energy and move faster. This makes them collide more frequently with each other, and a greater proportion of these collisions will have the required activation energy. As a result of this, the frequency of effective collisions increases, and so the rate of reaction increases.
Why does increasing temperature affect enzyme activity - practical
In our experiment best temp was 60 tho it should have denatured
Sodium carbonate (to make ph alkaline for phenolphthalein indicator turn pink)
Milk + lipase solution (more concentrated lipase)
Water bath to control temperature
Lipase turn lipids to fatty acids, making pink go away to transparent (now acidic)
This investigation should show you how temperature affects the breakdown of fats in milk by the enzyme lipase. As with many chemical reactions, the rate of an enzyme-catalysed reaction increases as the temperature increases. However, at high temperatures the rate decreases again because the enzyme can no longer function.
Why does ph affect enzyme activity - practical
Best at 6pH, after 8 it denatures
In one test tube with buffer + amylase + starch solution, mix
Pippete drop onto iodine solution
Measure time turn from black-blue to orange-brown (starch break down so no more present)
Water bath to regulate temperature
ENZYMES AND BIOLOGICAL MOLECULES
Starch ——amylase——> reducing sugars (maltose then glucose)
Lipids ——lipase——> fatty acids + glycerol
Proteins ——pepsin (type of protease in stomach) —-> animo acids
DEFICIENCIES
-> A deficiency disease is an illness caused by the lack of an essential nutrient in the diet, such as a vitamin, mineral or even protein.
Lack of vitamin D – Rickets
Lack of vitamin C – Scurvy
Lack of Iron – Anemia
Lack of calcium – Decreased bone density
PROCESS OF THE ALIMENTARY CANAL
Ingestion:
- Taking in food and drink into the body through the mouth
Digestion (Physical):
- breaking down food into smaller pieces without any chemical changes
Digestion (Chemical):
- breaking down large insoluble molecules in food into small soluble molecules, with the help of enzymes
Absorption:
- movement of nutrients from the intestine into the blood
Assimilation:
- Uptake and use of nutrients (for short)
- movement of digested food molecules from the blood into the cells of the body where they are used
Egestion:
- Removal of undigested food from the body as faeces
-
Digestive system
Oral cavity→ oesophagus → stomach → small intestine (duodenum and ileum) → large intestine (colon and rectum) → anus
ASSOCIATED ORGANS
organs in the digestive system in which food does not pass through
Salivary glands:
- produce saliva which contains salivary amylase
- Starch ——amylase——> reducing sugars (maltose to glucose)
Liver:
- produces bile
Gall bladder:
- stores bile before it is released through the bile duct into the duodenum
Pancreas:
- produces enzymes: protease, lipase, and amylase
- secretes pancreatic juice (alkaline because it contains a high concentration of hydrogencarbonate ions) to neutralize acid in food leaving the stomach
Function of bile
Bile is alkaline and neutralizes acidic food: chyme (chewed ball of food) from stomach. (Fats do not dissolve in water, which makes it difficult for lipase enzymes to break them down.)
This is important because the amylase and trypsin there work best under alkaline conditions (trypsin breaks down proteins after bile neutralized the gastric juices).
Emulsification is a physical digestion
where bile breaks large droplet of fat into small droplets of fat increasing surface area for digestive enzymes.
Physical vs chemical digestion
-> Physical digestion is the mechanical digestion or breakdown of food into smaller pieces. The actions of physical digestion are caused by the teeth in the mouth and the muscular wall of the stomach. This increases the SA:V ratio to create more space for enzymes to access substrates, to break food down further through chemical digestion.
Chemical digestion in the alimentary canal is the breakdown of large insoluble molecules into small, soluble molecules with different chemical properties so that it can be absorbed, with the help of enzymes.
Double circulatory system benefits
This has two important advantages.
1. Oxygen and glucose for respiration are supplied quickly to the cells in the body
- Waste products: carbon dioxide and water are removed quickly from them
- Blood can be supplied to distant parts of large animals
ECG
To record an ECG, small electrodes are fastened over the heart and other areas of the body of a person to record the electrical activity of the heart. This activity is recorded and represented in the form of a graph called an electrocardiogram.
Sound of heartbeat and pulse
Through a stethoscope, you will hear the valves in the heart closing with each heartbeat. The sound pattern is rather like ‘lub-dup, lub-dup, lub-dup’:
Therefore, each complete ‘lub-dup’ represents one heartbeat.
Pulse:
A pulse is a feeling near the surface of the skin. It is caused by the expansion and recoil of an artery due to the pressure of blood pumped from the heart.
Each time the left ventricle contracts, it creates a pulse. Your pulse rate is, therefore, the same as your heart rate.
Coronary heart disease
-> Coronary arteries are branches of aorta on the surface of the heart that supplies nutrients (glucose and oxygen) to the heart muscles.
Coronary heart disease (CHD) is when the coronary arteries are unable to supply oxygen rich blood to the heart muscles due to blockages of cholesterol and fats in them. The blockages reduce the diameters of the coronary arteries, making it difficult for the blood to flow through.. As a result, this heart muscle will be damaged and may die because of the loss of blood supply.
Risk factors
- Smoking
- Unhealthy diet
- Stress
- Sex (men more)
- Lack of exercise
- Genetics
- High cholesterol level
Preventing
- Consume a balanced diet, with oil from plants and fish while reducing amounts of animal fat
- Regular exercise
- Keep fit (suitable body mass)
- Have good health being
Components of blood
Blood contains:
- plasma – a watery fluid which transports blood cells, ions, soluble nutrients, hormones and carbon dioxide in the blood
- platelets – fragments of cells that are involved in clotting, for example, if the skin is damaged and bleeding begins
- red blood cells
- white blood cells
Red blood cells:
- transport oxygen in the blood
- biconcave (large SA:V ratio) for efficient oxygen absorption
- contains lots of haemoglobin
- no nucleus in mammals to provide space for oxygen and haemoglobin
Haemoglobin is a protein that gives red cells their colour (and so the colour of blood). It combines with oxygen when oxygen levels are high and releases it when oxygen levels are low.
White blood cells
-> White blood cells have a large, lobed nucleus and are almost colourless. White blood cells are part of the body’s immune system.
Depending on the type of cell, they can ingest and destroy pathogens (a process called phagocytosis), or they can produce antibodies (see topic 7).
The two main types of white blood cells are:
1. Phagocytes - the cells engulf pathogens by phagocytosis
2. Lymphocytes – the cells produce antibodies (proteins which attach to pathogens and mark them for destruction)
blood clotting
-> a clot is a plug of platelets that forms to prevent loss of blood and entry of pathogens from damaged vessels
Viruses
- are not made of cells
- do not have a cell membrane or cytoplasm
- do not show any of the seven characteristics of living organisms
Viruses consist of a protein coat surrounding genetic material. To reproduce, they insert their genetic material into the host cell and use the material of it to make new viruses.
Disease
-> a pathogen is an organism or agent that causes disease (bacteria, fungi, protoctists, and viruses)
An organism that is infected by a pathogen is called a host. A vector is an organism that transmits the pathogen from an infected to a non-infected person.
Once in the new host, the pathogen reproduces rapidly, producing huge numbers of new pathogens. The pathogens (or their waste products) damage the cells and the organs of the body.
Lines of defence
First line of defense:
- Mechanical barriers (block pathogens from entering the body)
-> includes skin, hair in nose
Ciliated cells line your nose and throat. The hairs of the nose trap dust particles and pathogens
- Chemical barriers (substances that trap or kill pathogens)
-> includes mucus, stomach acid
Mucous membranes produce mucus which is sticky and traps dust and pathogens. Acid secreted in the stomach kills microorganisms in food and water.
Second line of defense (white blood cells):
- Phagocytes - surround and engulf a pathogen through phagocytosis then destroy it
- Lymphocytes - produce antibodies, proteins which attach to pathogens and mark them for destruction
Active and passive immunity
-> Antigens are substances that can cause the body to produce an immune response found on the surface of a cell. Each pathogen has its own antigens, each with specific shapes.
Antibodies are proteins produced by lymphocytes that bind to antigens leading to direct destruction of pathogens (cause them to break open and die) or marking of pathogens for destruction by phagocytes.
An antibody for a particular antigen is complimentary to the shape of the antigens. This means the antibody can attach to an antigen on the surface of the pathogen to create an antibody-antigen complex.
Active immunity is the defense against pathogen by antibody production in the body. When the immune system responds to a particular pathogen for the first time, it is called a primary response.
Passive immunity can be gained from mother’s breastmilk, in which the antibodies go into the baby’s body.
MEMORY CELLS
Memory cells remain in the blood after the pathogens in an infection have been destroyed. These lymphocytes ‘remember’ particular pathogens by their specific antigens on their surface. If you are infected by the same pathogens again, they react quickly.
Your body produces so many antibodies, so quickly, that the pathogens are destroyed before they can spread through your body.
You are described as being immune (you get long-term immunity) to that infection. The production of memory cells is an important feature in vaccination to prevent disease.
Vaccination
Active immunity can be gained after an infection by a pathogen, but it can also be gained by vaccination.
It contains:
- Antigen of a specific pathogen
- Weakened pathogens
- A piece of genetic material (RNA)
- The vaccine is introduced into the body, either through the mouth (for vaccination against polio) or more commonly by injection.
- Lymphocytes in the immune system mount a primary response to the antigens from the pathogen. They produce antibodies to target these antigens and become memory cells.
- These memory cells remain in the blood after the pathogen has been destroyed. Some memory cells may last for the rest of your life; others will only last for a few years, so you may need a booster vaccination (you gain long-term immunity)
If a vaccinated person is infected by the live pathogen, the memory cells will recognize it very quickly. A secondary immune response is mounted, which destroys the pathogen, often before symptoms develop (see memory cells)
Heart rate practical
Method:
1. Sit down and relax.
2. Find your pulse, then count the number of pulses in 15 seconds. Multiply this by 4 to find your heart rate in beats/minute. Record this number.
3. Run on the spot for 2 minutes.
4. Sit down and measure your heart rate again
- immediately
- after 2 minutes
- after 4 minutes.
In most people, at rest, the heart rate is between 60 and 75 beats per minute. This should be much higher immediately after exercising but will gradually return to its resting rate over the next few minutes. In general, the quicker this happens, the fitter you are.
Conclusion:
In general, the heart rate increases with exercise. Muscle cells need more energy when you exercise than when you are at rest. This energy comes from aerobic respiration.
More glucose and oxygen must be supplied by the blood to the respiring muscle cells. Your heart beats faster in response, increasing the blood flow to these cells, and increasing the rate at which waste products of respiration (carbon dioxide and water) are removed.
