| What is a cell? | The basic building block of life. |
| What is the process of cell differentiation? | As a cell becomes differentiated, it develops different sub cellular structures.
This mostly happens when an organism to develop and in most animal cells, the ability to differentiate is lost, whereas this is not the case in plant cells. |
| What do specialised cells form? | Tissues. |
| What do large multicellular organisms have for exchanging and transporting materials? | Organ systems. |
| What is a tissue? | A group of similar cells working together to perform a certain function. |
| What do muscular tissues do? | They contract and move whatever is attached to it. |
| What do glandular tissues do? | They make and secrete chemicals like enzymes and hormones. |
| What do epithelial tissues do? | They cover some parts of the boy like the gut. |
| What is an organ? | A group of different tissues that work together to perform a certain function. |
| What type of tissues is the stomach made up of and what do they do? | Muscular tissues move the stomach walls to churn the food.
Glandular tissue makes the digestive juices that digest foods.
Epithelial tissues cover the outside and inside of the stomach. |
| What is an organ system? | A group of organs working together to perform a certain function. |
| What organs make up the digestive system and what do they do? | Glands (pancreas and salivary glands) produce digestive juices.
The stomach and small intestine digest food.
The liver produces bile.
The small intestine absorbs soluble food molecules.
The large intestine absorbs water and undigested food, leaving feces. |
| What do organ systems make? | Organisms. |
| What is an enzyme? | Proteins that are bodily catalysts, they speed up reactions without being used up. |
| What are enzymes made up of? | Large proteins which are made up of chains of amino acids. |
| How does temperature affect the rate of an enzyme? | It changes the rate of an enzyme-catalyzed reaction.
When the temperature gets higher, it increases the rate.
If it gets too hot, the bonds holding the enzyme together will break, changing the active site shape, and denaturing the enzyme since the substrate won't fit anymore. |
| How does pH affect the rate of an enzyme? | If the pH is too high or too low, it can break the bonds holding the enzyme together.
This changes the shape of the enzyme and denatures it.
The optimum pH is usually pH 7, but some like pepsin works best at pH 2 since it's in the stomach. |
| Why do enzymes break down molecules? | They break down big molecules so that they can turn into smaller more soluble molecules that can be easily absorbed into the bloodstream. |
| What does amylase break down and into what? | Amylase breaks down starch into maltose. |
| Where is amylase made? | The salivary glands, the pancreas and the small intestine. |
| What does protease break down and into what? | Protease breaks down proteins into amino acids. |
| Where is protease made? | The stomach (it's called pepsin there), the pancreas and the small intestine. |
| What does lipase break down and into what? | Lipase breaks down lipids into fatty acids and glycerol. |
| Where is lipase made? | The pancreas and the small intestine. |
| What is bile? | A fluid that is produced in the liver and stored in the gall bladder.
It's released into the small intestine and emuslifies fats into small droplets will large surface areas, so lipase can break it down, increasing the rate of breakdown.
It also neutralises stomach acids. |
| What is the gullet? | The oesophagus. |
| What does the stomach do? | It pummels food with the muscular walls.
It produces protease.
It produces hydrochloric acid. |
| What does hydrochloric acid do? | It kills bacteria and it provides the right pH for protease. |
| What does the small intestine do? | It produces protease, amylase and lipase, and absorbs food into the blood. |
| What does the pancreas do? | It produces protease, amylase and lipase, and releases them into the small intestine. |
| What does the large intestine do? | Here, excess water is absorbed from the food. |
| What does the rectum do? | Faeces is stored here. |
| What do the salivary glands do? | They produce amylase in saliva. |
| What is the food test for sugars? And what are the positive and negative results? | The food test for sugars is Benedict's solution.
It goes from blue to brick red.
It can also go to green then yellow in between depending on how much sugar is in the food. |
| What is the food test for starch? And what are the positive and negative results? | The food test for starch is Iodine solution.
It goes from browny-orange to blue-black. |
| What is the food test for protein? And what are the positive and negative results? | The food test for protein is Biuret solution.
It foes from blue to purple. |
| What is the food test for fats? And what are the positive and negative results? | The food test for fats is Ethanol.
It goes from clear to cloudy. |
| What is the thorax? | The upper part of your body. |
| What are the lungs surrounded by? | Pleural membranes. |
| What are the bronchi (bronchus)? | Two tubes that the trachea splits into. |
| What are bronchioles? | Smaller tubes that the bronchi split into. THey're air passages. |
| What are alveoli? | Air sacs in which gas exchange happens. Oxygen diffuses out of the alveolus into the blood, and carbon dioxide diffuses out of the blood into the alveolus to be breathed out. |
| QUESTION
Bob takes 91 breathes in 7 minutes.
Calculate his average breathing rate in breaths per minute. | Breaths per minute = number of breaths ÷ number of minutes
91 ÷ 7
= 13 breaths per minute. |
| Why is it called a DOUBLE circulatory system? | Because we have two circuits joined together. |
| What does the right ventricle do? | It pumps deoxygenated blood to the lungs so they can become oxygenated. |
| What does the left ventricle do? | It pumps oxygenated blood to the body. |
| What do valves do? | They prevent the backflow of blood. |
| How does deoxygenated blood enter the heart? | Through the vena cava. |
| How does oxygenated leave the heart? | Through the aorta. |
| How does deoxygenated blood leave the heart? | Through the pulmonary artery. |
| How does oxygenated blood enter the heart? | Through the pulmonary vein. |
| What do coronary arteries do? | They branch off the aorta and provide the heart muscles with oxygen. |
| What is a natural pacemaker? | A SA node that sends electrical impulses around the heart so the ventricles can contract and pump blood. |
| What are cardiovascular diseases? | Diseases of the heart or blood vessels. |
| What is coronary heart disease? | A diseases where the coronary artery becomes blocked and narrowed due to a build up of fatty deposits, reducing the amount of oxygenated blood that the heart receives. |
| What are stents? | Tubes that are inserted then blown up inside the artery so it can open the artery and allow more blood to go through. |
| What are the 3 advantages of stents? | They can lower the risk of heart attack for those with coronary heart disease.
They can be very effective.
Recovery from surgery is quick. |
| What are 3 disadvantages of stents? | There can be complications during surgery (heart attack).
There can be a risk of infection from surgery.
The patient may develop blood clots. |
| What are statins? | Drugs that can reduce the amount of cholesterol in your bloodstream. It also slows down the rate of fatty deposits forming. |
| What are 3 advantages of statins? | They reduce the risk of stroke and heart attacks.
They can prevent other diseases.
They can increase the amount of HDL cholesterol. |
| What are 3 disadvantages of statins? | They have to be taken regularly, so there is a risk of forgetting to take them.
They can have negative side effects - headaches, liver damage, kidney failure and memory loss.
IT takes time for the effects of statins to kick in. |
| What is LDL cholesterol? | Excess cholesterol that desposits on the walls of vessels, leading to clots. |
| What is HDL cholesterol? | Cholesterol that returns to the liver to be metabolized. |
| What is artherosclerosis? | When the arteries gradually narrow over years. |
| What happens during bypass surgeries? | It replaces blood vessels to stop blockage. |
| What happens during heart transplants? | The heart is replaced with a donor's. |
| What do arteries do? | They carry blood away from the heart. |
| What do capillaries do? | They allow materials to be exchanged. |
| What do veins do? | They carry blood to the heart. |
| What are the artery walls like and why? | They are thick, elastic and strong so that the muscles can stretch and pump blood under high pressure. It carries oxygenated blood. They also branch into capillaries. |
| What are the vein walls like and why? | They are thin with a large lumen with valves. It carries deoxygenated blood under low pressure. |
| What are the capillaries walls like and why? | They are one cell thick, increasing the rate of diffusion and decreasing the distance, and are permeable. |
| What is the equation for rate of blood flow? | Rate of blood flow = volume of blood ÷ number of minutes |
| QUESTION
1464 ml of blood passed through an artery in 4.5 minutes. Calculate the rate of blood flow through the artery in ml/min. | Rate of blood flow = volume of blood ÷ number of minutes
1464 ÷ 4.5
= 325 ml/min |
| What do red blood cells do? | They carry oxygen from the lungs to the rest of the body. |
| How are red blood cells adapted to do their job? | They're shaped like a biconcave disc to give them a larger surface area for absorbing oxygen.
They don't have a nucleus, so this maximizes the amount of oxygen they can carry.
They contain a red pigment called hemoglobin which binds to oxygen, becoming oxyhemoglobin. |
| What do white blood cells do? | They defend the body against infection. |
| How are white blood cells adapted to do their job? | Phagocytes engulf and destroy microorganisms through phagocytosis.
Antibodies are produced with a complementary shape that bind to antigens on pathogens.
Antitoxins neutralise toxins produced by pathogens. |
| What do platelets do? | Help to clot blood at wounds so blood doesn't pour out and so that microorganisms dont get in. |
| How are platelets adapted to do their job? | They are small fragements of cells with no nucleus that clot at wounds. |
| What does plasma do? | Plasma carries everything in blood. It carries;
Ted and white blood cells and platelets.
Nutrients like glucose and amino acids.
Urea from the liver to the kidneys.
Hormones.
Proteins.
Antibodies and antitoxins are produced by white blood cells. |
| How do artificial hearts help patients? | They can pump blood for a person whose heart has failed. |
| What is an advantage of artificial hearts? | They are less likely to be rejected since the materials aren't recognised as foreign. |
| What are 5 disadvantages of artificial hearts? | The surgery can lead to bleeding or infection.
They dont work as well as normal hearts - parts of the heart could wear out or the motor can fail.
Blood clots may form, leading to strokes.
The patient needs to take drugs to thin their blood.
Thinning the blood can lead to problems when bleeding. |
| What is health? | The state of physical, social and mental wellbeing. |
| What are communicable diseases? | Diseases that can spread one infected person to another person, animal or object. They are caused by pathogens. |
| What are non-communicable diseases? | Diseases that cannot spread from an infected person. This means you have to develop them. |
| What factors can affect health? | Diet, stress and life situation. |
| What interactions can be caused by diseases? | Some cancers can be triggered by certain viruses - hepatitis virus can lead to liver cancer.
Severe physical health problems can cause depression.
Immune system problems can cause an increased chance of suffering from communicable diseases.
Immune system reactions caused by pathogens can lead to allergic reactions like skin rashes. |
| What are some human costs of non communicable diseases? | Tens of millions of people die from them per year.
People with these diseases have a lower quality of life or shorter lifespan. |
| What are some financial costs of non communicable diseases? | Researching and treating the disease.
Families may have to move and adapt to help a family member with the disease.
Reduction in the number of people who can work can affect families and the country's economy. |
| What is a risk factor? | Something that increases the chance of getting a disease. |
| What is smoking a risk factor of and how? | Cardiovascular disease, lung disease and lung cancer.
This is because it damages the walls of arteries and cells in the linings of the lungs. |
| What is obesity a risk factor of how? | Type 2 diabetes.
This is because it makes the body less sensitive or resistant to insulin, so it struggles to control glucose concentration in the blood. |
| What is alcohol a risk factor of and how? | Liver disease and brain damage.
This is because the reaction of breaking down alcohol can damage the cells when toxic chemicals leak from the gut due to damage in the intestines.
This is because it damages nerve cells, making the brain lose volume. |
| How can smoking and affect pregnancy? | It reduces the amount of oxygen the baby receives and can cause health problems. |
| How ca alcohol affect pregnancy? | It can damage the baby's cells, affecting its development. It can also cause health issues. |
| What are carcinogens? | Things that can cause cancer. |
| What is a way carcinogens can work? | They can damage a cell's DNA, making it more likely for it to divide uncontrollably. |
| What is an example of a carcinogen? | Ionising radiation - e.g. X-rays. |
| What is correlation? | A way for scientists to identify risk factors. |
| How is a lack of exercise and a high-fat diet a risk factor, even though it can't directly cause a disease? | It can increase the chance of cardiovascular disease but it can't cause it. The result of high blood pressure and LDL cholesterol levels cause the disease. |
| What is cancer? | The uncontrolled growth and division of cells, forming a tumor. |
| What is a benign tumour? | A tumour that grows until there is no more room.
It stays in one place - usually a membrane - and isn't normally dangerous or cancerous. |
| What is a malignant tumour? | A tumour that grows and spreads to tissues and cells, creating secondary tumors.
It travels in the bloodstream.
They are dangerous and cancerous. |
| What cancers can smoking cause? | Mouth, bowel, stomach and cervical cancer. |
| What cancers can obesity cause | Bowel, liver and kidney cancer. |
| What cancer can UV exposure cause? | Skin cancer. |
| What cancer can hepatitis B and hepatitis C cause? | Liver cancer. |
| What are 4 lifestyle risk factors? | Smoking, obesity, UV exposure and viral infections. |
| What mutations have been linked to an increased likelihood of developing breast and ovarian cancer? | Mutations in BRCA genes. |
| What are the 4 organs of a plant? | Stems, roots, leaves and flowers. |
| What does the upper epidermal tissue do and what is its adaption for its function? | It allows light to pass through, and it produces the waxy cuticle.
It does this by being thin. |
| What does the palisade mesophyll tissue do and what is its adaption for its function? | This is where the vast majority of photosynthesis happens.
It does this by having lots of chloroplasts and by being deep and tightly packed to absorb light. |
| What does the spongy mesophyll tissue do and what is its adaption for its function? | Lets gases diffuse in and out of cells.
It does this by having air pockets. |
| What does the xylem do and what is its adaption for its function? | It transports water and mineral ions from the roots to the leaves through the transpiration stream.
It does this by; having dead cells - making it impermeable; having tick cell walls containing lignin - strengthening it; having a space with no cytoplasm. |
| What does the phloem do and what is its adaption for its function? | It transports sugars/ glucose all around the plant through a process called translocation.
It does this by having; companion cells to keep the phloem alive; a two-way flow; end walls with perforations, protecting the phloem sap from intruding animals by blocking flow when the phloem cell is damaged. |
| What does the waxy cuticle do and what is its adaption for its function? | It prevents water loss. It does this by being waterproof. |
| What does the lower epidermis do? | It has holes called stomata for gas exchange.
The underside also reduces water loss. |
| What does the stomata do? | Allows the diffusion of gases in and out of the leaves.
They are usually found on the underside of leaves since its cooler and shaded, meaning less water is loss if they were on the upperside. |
| What do guard cells do? | They change shape due to osmosis and open and close the stomata. |
| What is transpiration? | The evaporation and diffusion of water from the leaves. |
| What is the transpiration stream? | The evaporation of water from the leaves through the stomata. The movement of water causes a pull, drawing more water from the toors causing a constant transpiration stream. |
| What are the 4 main things that affect the rate of transpiration? | Light intensity, temperature, wind intensity and humidity. |
| How does light intensity affect tranpiration? | The brighter and more light there is the greater the transpiration rate. It will increase photosynthesis, opening the stomata for more gas exchange, and allowing water to escape. |
| How does temperature affect transpiration? | The warmer it is, the faster transpiration happens. This is because water particles will get more energy and evaporate, diffusing out of the stomata. |
| How does wind intensity affect transpiration? | The greater the wind intensity, the greater the transpiration rate. The water vapour will be carried away, meaning that the concentration gradient of water outside the leaf will be lower than inside, causing diffusion to happen quickly. |
| How does humidity affect transpiration? | The drier the air around the leaf, the faster transpiration happens. If the air is humid, that means there's a lot of water in it, so the concentration difference wont be great. |
| How do guard cells open and close the stomata? | When the cell has plenty of water, it becomes turgid, making the cell swollen. This curves the guard cells away from each other, opening the stomata, and allowing gases to be exchanged for photosynthesis.
When too much water leaves, the cell becomes flaccid and relaxes, closing the stomata.
They have thin outer walls and thickened inner walls to open and close and are light sensitive, so they close at night to save water.
They're adapted for gas exchange and controlling water loss in leaves. |
