Organisation Flashcards
What is the name of the process where cells become specialised for different jobs?
Differentiation
What are the stages of organisation?
Cells -> tissues -> organs -> organ systems
When does differentiation occur?
During the development of a multicellular organism
What is a tissue?
A group of similar cells that work together to carry out a particular function. It can include more than one type of cell. E.g. muscular tissue
What is an organ?
A group of different tissues that work together to perform a certain function. E.g. the stomach.
What is an organ system?
A group of organs working together to perform a particular function. E.g. the digestive system.
What are enzymes?
biological catalysts produced by living things. They are large proteins made up of chains of amino acids.
What do enzymes do?
Speed up the useful chemical reaction in the body and control them in order to get the right amount of substances
What is a catalyst?
A substance which increases the speed of a reaction, without being changed or used up in the reaction
What is the lock and key theory?
Every enzyme has an active site with a unique shape that only fits onto the substance involved in its reaction. If they enzyme and substrate don’t fit, the reaction won’t be catalysed.
How does temperature affect enzymes
Enzymes have optimum temperatures. Higher temperatures increased reactions at first but if it gets too hot the enzymes are denatured, changing the shape of the active site as the bonds holding them together break.
How does pH affect enzymes?
All enzymes have an optimum pH. Normally neutral at 7. If its too high or too low it affects the bonds holding the enzyme together which denatures it, changing the shape of its active site.
How do you investigate the effect of pH on enzyme activity?
- fill a spotting tile with drops of iodine solution
- heat a beaker of water inside it to 35 degrees Celsius using a Bunsen burner, keep this constant
- Add 1cm^3 of amylase solution and 1cm^3 of buffer solution with pH 5 to a boiling tube and put it into the hot water.
- Add 5cm^3 of starch solution and mix
-start a stop watch - Time how low long it takes for the starch to be broken down by put a sample of the boiling tube solution into the spotting tile every 30 seconds
-starch is present if the iodine changes colour to dark blue - Repeat the experiment with different pH values each to to see how the results change
What is the formula for rate of reactions in the experiment to test the efficency of enzymes ?
Rate = 1000/time
What happens when a molecule like starch proteins and fat are too big to travel down the digestive system?
Enzymes break them down into smaller ones like sugars, amino acids, glycerol and fatty acids
Protease breaks down proteins. Where is it made?
In the stomach, pancreas and small intestine
Amylase breaks down carbohydrates. Where is it made?
In the salivary glands, pancreas, and small intestine
Lipase breaks down lipids. Where is it made?
The pancreas and small intestine
Where is bile produced, stored and released?
Produced in the liver, stored in the gall bladder, and released into the small intestine.
What does bile do?
Neutralises stomach acid and, making condition alkaline to stop enzymes from denaturing. It emulsifies fat to give it a bigger surface area
What is the thorax?
The top part of your body
How does air get into the blood?
Thorax -> bronchi -> bronchioles -> alveoli where gas exchange takes place
How do the alveoli carry out gaseous exchange?
They are surrounded by blood capillaries. Oxygen diffuses out of the alveoli into the blood and carbon dioxide diffuses out of the blood and into the alveoli
How does oxygen get from the blood to the body cells?
When blood gets to the body cells oxygen diffuses out of the red blood cells and into the blood and carbon dioxide diffuses out of the cells and into the red blood cells to be taken back to the lungs
How does the first human circulatory system work?
Right ventricle pumps deoxygenated blood to the lungs to take in oxygen and then it goes back to the heart.
How does the second human circulatory system work?
The left ventricle pumps oxygenated blood around the body where it gives oxygen to the cells and returns to the heart as deoxygenated blood
What cycle does blood take through the heart on each side?
vena cava / pulmonary vein -> atria -> ventricles -> pulmonary artery / aorta ->out
How does the heart get its own supply of blood?
Through coronary arteries that branch off the aorta, surrounding the heart.
What controls the heart rate?
A group of cells in the right atrium wall that act as a pacemaker, producing electrical impulses to make surrounding muscles contract
What do arteries do and how are they adapted to their function?
-strong, thick, elastic walls to carry the blood the heart is pumping out at high pressure
-thick layers of muscle and elastic fibres so they can stretch and spring back
What are the three types of blood vessel?
Arteries, capillaries and veins
What do capillaries do and how are they adapted to their function?
-really tiny
-carry blood to every cell to exchange substance so are very close to them
-permeable walls for diffusion, very thin (only one cell thick)
-supply food and oxygen, take away waste
What do veins do and how are they adapted to their function?
-Carry blood at lower pressures so walls aren’t very thick
-bigger lumen to help blood flow
-valves to keep the blood flowing in the right direction
How are red blood cells adapted to their function?
- Biconcave discs - increases surface area to volume ratio
- Haemogobin
- No nucleus - more space for haemoglobin
How are white blood cells adapted to their function?
-they do have a nucleus
-some change shape (phagocytosis) to absorb and break down pathogens
-others make antibodies and antitoxins to neutralise pathogens
What are platelets?
Small fragments of a cell with no nucleus that help blood clot at a wound and stop microorganisms getting in
What does plasma carry?
-red and white blood cells
-platelets
-nutrients (like glucose and amino acids)
-carbon dioxide from organs to lungs
-urea from liver to kidneys
-hormones
-proteins
-antibodies and antitoxins
What are stents and what do they do?
They are tubes that go inside the arteries to keep them open to make sure that the heart is supplied with blood and can keep beating which lowers the risk of a heart attack but their is a risk of complications during (heart attack) and after (infection and blood clots) the operation.
What is coronary heart disease (CHD)?
When the coronary arteries that supply the blood to the muscle of the heart get blocked by layers of fatty material building up, restricting blood flow (oxygen) from the heart
What are statins and their advantages and disadvantages?
Drugs that reduce the amount of bad cholesterol in the blood stream. They reduce the risk of CHD, strokes and heart attacks and may even help prevent other diseases but they’re a long term drug and have some side effects like kidney failure, liver damage and memory loss.
What is cholesterol?
A lipid that the body needs but having too much ‘bad’ cholesterol can cause CHD because it causes fatty deposits to form in the arteries
What are artificial hearts?
There is often a shortage of organ donors and so if someone needs a heart transplant, artificial hearts may be used, usually as a temporary fix. These are mechanical devices that pump blood.
How is valve damage treated?
By using replacement valves from humans, other mammals or even artificial mechanical ones. This surgery can cause blood clots.
What are the advantages and disadvantages of artificial hearts?
Because they’re made of metals or plastics, they are less likely to be considered ‘foreign’ and rejected by the body. But the surgery can lead to bleeding and infection and the hearts don’t work as well as human ones as blood doesn’t flow through as smoothly.
What is artificial blood?
A blood substitute (e.g. saline solution) used to replace lost volume of the blood. It can keep people alive even if they lose 2/3 of their red blood cells. Ideally it would replace the function of the lost red blood cells to avoid a transfusion.
What is the difference between communicable and non-communicable diseases?
Communicable diseases can be spread from person to person or between animals and people, caused by bacteria, fungi, protists etc. Non-communicable diseases can’t be spread between organisms and tend to last, and deteriorate, for a long time.
What is an example of diseases interacting?
Some types of cancer can be caused by viral infection e.g. hepatitis causing long-term liver infections which can lead to liver cancer. HPV causing cervical cancer in women. Mental health issues can be triggered by physical health issues.
What other factors can affect your health?
Diet, stress, life situation
What are risk factors?
Things that increase your likelihood of getting a disease. They are often caused by aspects of your lifestyle of substances in the environment (air pollution) or in your body (asbestos). Non-communicable diseases are normally caused by a number.
What are examples of risk factors directly causing a disease?
-smoking -> cardiovascular disease, lung cancer, lung disease
-obesity -> type 2 diabetes
-too much alcohol -> liver disease, damaged brain nerve cells
-smoking and drinking while pregnant -> disease in fetus
-radiation exposure -> cancer
What is the difference between a benign and malignant tumour?
Benign tumours do not spread but simply grow until there’s no more room, usually within a membrane, it doesn’t invade other tissues and isn’t normally cancerous. Malignant tumours do spread and cells can break off and travel around the body in the blood stream. These are cancerous and can be fatal.
What causes cancer?
Uncontrolled cell growth and division.
What are the risk factors associated with cancer?
-smoking -> lung, mouth, bowel, cervical
-obesity -> bowel, liver, kidney
-UV exposure -> skin
-Viral infection (e.g. hepatitis) -> all different types of cancer
-faulty genes
-mutations -> e.g. in the BRCA gene which can increase the chance of breast and ovarian gene
What does the epidermal tissue do and how is it adapted to it’s function?
-covers whole plant
-has waxy cuticle to prevent water loss
What does the upper epidermis do and how is it adapted to it’s function?
-lets light in
-it’s transparent
What does the palisade mesophyll tissue do and how is it adapted to it’s function?
-where most of the photosynthesis happens
-losts of chloroplasts, is at the top of the leaf to get light
What does the spongy mesophyll tissue do and how is it adapted to it’s function?
-where gases diffuse in and out of cells
-has big air spaces
What does the xylem and phloem do and how is it adapted to it’s function?
-transport water and minerals (xylem), and food (phloem) through roots, stems and leaves
-form a network of vascular bundles
What does the lower epidermis do and how is it adapted to it’s function?
-where gas exchange happens
-full of little wholes (stomata) to let CO2 diffuse in
What does the meristem tissue do and how is it adapted to it’s function?
-differentiates into all types of plant cells, allowing it to grow
-found at growing tips of shoots and roots
What is translocation?
The transport of food substances made in the leaves through the columns of long living cells with small pores (phloem). This goes in both directions.
What is the transpiration stream?
The movement of water from the roots through the joined up dead cells (xylem) and out of the leaves. This only goes one way.
What causes transpiration?
The evaporation and diffusion of water from a plants surface which creates a slight water shortage in the leaf meaning more water needs to be drawn up
What are the four things that affect the rate of transpiration?
-Light intensity
-temperature
-air flow
-humidity
How can you estimate the rate of transpiration?
By measuring the uptake of water by a plant
How are guard cells adapted to open and close stomata to control gas exchange and water loss?
-fill up to open the stomata when a plant has lost of water
-empty out to close the stomata when the plant loses water
-thin outer walls and thick inner walls
-close at night when it’s dark as there’s no photosynthesis
