Unit 3A - Life Processes Flashcards
Why do water molecules pass both ways through the membrane during osmosis?
Because they are moving about randomly all the time and so some will be going from the are of low concentration to an are of high concentration
What’s the definition of osmosis?
Osmosis is the movement of water molecules across a partially permeable membrane from an area of high water concentration to an are of low concentration
How does water move in and out of cells?
By osmosis
If a solution is quite concentrated does it contain a lot of water?
No
What happens to water molecules when a cell is short of water?
The solution inside it is quite concentrated and so the concentration outside of it is more dilute, and so water will move into the cell by osmosis
What experiment can you do to show osmosis and what would you find?
Cut potato up into cylinders and place them in beakers of pure water and a very concentrated sugar solution, and measure their length before and after a few hours of being the beaker. If the cylinders have drawn in water by osmosis they will be longer, and if water has been drawn out they will have shrunk. The water will be drawn out in the rich sugar solution because the water concentration is higher in the potato
What are the three ways that substances can move?
By osmosis, diffusion and active transport
What do life processes need before they can happen?
Gases or other dissolved substances
What is the definition of diffusion?
Where particles move from an area of high concentration to an area of low concentration
What’s similar between diffusion and osmosis?
They both involve stuff moving from an area where there’s a high concentration of it to an area where there’s a low concentration of it
What is different about the way particles move in active transport compared to osmosis or diffusion?
Active transport involves particles moving from an area of lower concentration to an area of high concentration which is the opposite to diffusion and osmosis
What four ways are exchange surfaces adapted to maximise effectiveness?
- ) They are thin so substances have a shirt distance to diffuse
- ) They have a large surface area so lots of a substance can diffuse at once
- ) Exchange surfaces in animals have lots of blood vessel, so the substance can get into and out of the blood quickly
- ) Gas exchange surfaces are ventilated
How does carbon dioxide go from the air into the leaf for photosynthesis?
Carbon dioxide diffuses into air spaces in the leaf, and then it diffuses into the cells whee photosynthesis happens
What part of the cell does carbon dioxide diffuse through?
The stomata
What diffuses out of the stomata after photosynthesis has happened?
Oxygen and water vapour
What controls the size of the stomata?
The guard cells
Why are leafs a flattened shape?
To increase the area of gas exchange surface so that it is more effective
What conditions does evaporation happen fastest in?
Hot, dry, windy conditions
Why do humans so oxygen from the air?
For respiration
What part of the body are the lungs in?
The thorax
What part of the body separates the thorax and the abdomen?
The diaphragm
What protects the lungs?
The rib cage
How does gas get from the air to where the gas exchange takes place?
As you breathe in the air goes through the trachea, this splits into two tubes called bronchi, one going into each lung, the bronchi splits into smaller tubes called bronchioles, these finally end at small bags called alveoli which is where gas exchange takes place
What is ventilation?
The movement of air into and out of the lungs
What happens as you breath in?
Intercostal muscles and diaphragm contract, thorax volume increases, decreasing the pressure drawing air in
What happens when you breath out?
Intercostal muscles and diaphragm relax, thorax volume decreases, this increases the pressure so the air is forced out
What are artificial ventilators and who are they for?
Machines that move air into and out of the lungs, people who can’t breathe by themselves like if they are under general anaesthetic or have lung injury or disease
What was an old fashion artificial ventilator called?
An iron lung
How did an iron lung work?
They were a giant case from the neck to the abdomen, air was pumped out of the case, pressure dropped, the lungs expanded and so air was drawn in, when air was pumped into the case it has the opposite effect forcing air out of the lungs
What two parts of the body are adapted so that substances can diffuse through them most effectively?
Gas exchange in the lungs and how digested food gets from the gut into the blood
Where does the gas exchange take place in the lungs?
In the million of tiny air sacs called alveoli
What four ways are alveoli specialised to maximise the diffusion of oxygen and CO2?
- ) Enormous surface area
- ) Moist lining for dissolving gases
- ) Very thin walls
- ) A good blood supply
Roughly what is the surface are of all the alveoli in the body?
75m squared
What is the small intestine covered in?
Millions and millions of tiny projections called villi
What three ways are villi specialised for absorbing food?
- ) large surface area so that food is absorbed more quickly
- ) single layer of surface cell
- ) good blood supply to assist quick absorption
Besides active transport going against the concentration gradient what is another difference between it and diffusion?
It requires energy
How do particles move during active transport?
Against the concentration gradient, from a lower to a higher concentration
How are root hairs specialised for absorbing water and minerals?
The cells on the surface of the root grow into long hairs giving them a bigger surface area increasing the rate of absorption
Do root hairs use diffusion, osmosis or active transport?
Active transport
Why does active transport happens on root hairs?
The concentration of minerals is usually higher on the root hair cells than in the soil around it, so diffusion can’t happen if the root hair cell are to take up nutrients, this is why active transport happens as it works against the concentration gradient
What is active transport essential for in plants?
Growth
Where does active transport take place in humans?
In taking nutrients from the gut into the blood
Why does active transport and diffusion have to take place in the gut?
When there’s a higher concentration of glucose and amino acids in the gut they diffuse naturally into the blood however when there is a lower concentration of nutrients in the gut it means that the concentration gradient is the wrong way and so active transport has to be used to continually absorbs nutrients
What does active transport allow the gut to do?
All nutrients to be taken into the blood even when the concentration gradients is the wrong way
What are the names of the two vessels that transport stuff around plants?
Xylem and phloem
What do the phloem and xylem transport?
Phloem transports food substances (mainly dissolved sugars), and the xylem tube carries water and minerals up the plant
Which directions do the xylem and phloem transport stuff?
Phloem - both ways
Xylem - upwards only
What is the phloem made off?
Living cells with small holes in the end to allow stuff to flow through
What is the xylem made of?
Made of dead cells joined end to end with no end walls between them and a hole down the middle
What is transpiration in plants?
The loss of water from the plant
What is transpiration caused by?
Evaporation and diffusion of water from inside the leaves
What does transpiration stream mean?
As water is lost through transpiration more water is drawn from the roots creating the constant transpiration stream
What is the circulatory systems function?
To get food and oxygen to every cell in the body and to carry waste products like carbon dioxide and urea to where they can be removed
Do we have a single or double circulatory system?
Double
What are the two different circulatory systems?
The first one pumps deoxygenated blood to the lungs to take in oxygen and the returns it to the heart, the second one pumps oxygenated blood around all the other organs of the body, when the blood gives up its oxygen at the body cells the deoxygenated blood is returned to the heart.
What in the heart makes sure the blood goes in the right direction?
The valves prevent blood from flowing backwards
What are the four chambers in the heart?
Right atrium, right ventricle, left atrium and left ventricle
How does blood pump around the heart?
Blood flows into the two atriums through the vena cava and the pulmonary vein
The atrium contact pushing the blood through the value and into the ventricles
The ventricles contract forcing the blood into the pulmonary artery and the aorta and out of the heart
The blood them flows to the organs through the arteries and returns through the veins
The cycle starts again
What is the name of the main artery and vein in the right side of the heart?
Artery - pulmonary artery
Vein - vena cava
What is the name of the main artery and vein in the left side of the heart?
Vein - pulmonary vein
Artery - aorta
What is the name of the two main arteries in the heart?
Pulmonary artery and the aorta
What is the name of the two main veins in the heart?
Vena cava and the pulmonary vein
Do vein transport blood away from the heart?
To into the heart
What transports blood away from the heart?
Arteries
What are the three types of blood vessels and what are this main function?
Arteries - carry blood away from the heart
Capillaries - these are involved in the exchange of materials at the tissues
Veins - carry the blood to the heart
How are arteries designed to carry blood under high pressure?
They have thick walls, contain a thick layer of muscle to make them string, and elastic fibres to allow them to stretch and spring back
What is the name of the hole through the middle of arteries, capillaries and veins?
Lumen
What do arteries branch into?
Capillaries
How big are capillaries?
Really tiny
What do capillaries do?
Carry blood really close to every cell in the body to exchange substances with them, supply food and oxygen and take away waster like CO2
How are capillaries designed to exchange substances?
They have permeable walls so substances can diffuse in and out, walls are only one cell thick to increase the rate of diffusion by decreasing the distance over which it occurs
Capillaries join up to form?
Veins
Why don’t the walls in the veins have to big very thick?
The blood is at a lower pressure
Why do veins have bigger lumen?
To help the blood flow despite the lower pressure
Do arteries or veins have valves and why?
Veins to keep the blood flowing in the right direction
What is the job of the red blood cells?
To carry oxygen from the lungs to all cells in the body
What is the red pigment in red blood cell?
Haemoglobin
How are red blood cells adapted for their job?
They are concave with a large surface area for absorbing oxygen, and they don’t have a nucleus to make more room for carrying oxygen and haemoglobin
Between red blood cells and white blood cells, which ones have a nucleus?
White blood cells
In the lungs, haemoglobin combines with oxygen to become?
Oxyhemoglobin
What are the four main things in the blood?
Red blood cells, white blood cells, platelets and plasma
What is the job of the white blood cells?
To defend against disease
How do white blood cells defend against disease?
They produce antibodies to goth microorganisms as well as antitoxins to neutralise any toxins produced by microorganisms
What is the job if platelets in the blood?
They help the blood to clot at a wound to stop your blooding pouring out and microorganisms getting in
Do platelets have a nucleus?
No
What does plasma look like and what it’s job?
A pale straw coloured liquid which carries everything in the blood
What does plasma carry?
Red blood cells, white blood cells, platelets, nutrients like glucose and amino acids, carbon dioxide, urea, hormones, antibodies and antitoxins
What is artificial blood?
A blood substitute e.g. saline which is used to replace lost volume of blood
Artificial blood can keep you alive if you lose what amount of red blood cells?
2/3
If a patient has lost more than 2/3 of their red blood cells what do they need?
A blood transfusion
What are artificial hearts?
Mechanical devices that are out into a person to pump blood is their own heart fails
What is the main advantage of artificial hearts?
They’re not rejected by the body’s immune system
Why aren’t artificial hearts rejected by the body immune system?
They’re made from plastics or metals so the body doesn’t recognise them as foreign and attack them the same way as living tissue
What are six disadvantages of using artificial hearts?
The surgery can lead to bleeding and infection, they don’t work as well as a healthy natural heart, parts of the heart can wear out, the electrical motor can fail, blood doesn’t flow through them as smoothly which can lead to blood clots and strokes, and the patient has to take drugs to thin their blood which can lead to problems of they are injured
What can be done if heart valves are defective?
They can be replaced with mechanical ones
What is coronary heat disease?
When the arteries that supply blood to the muscle of the heart get blocked by fatty deposits, this causes the arteries to become narrow and the blood flow is restricted resulting in a heart attack
What are stents?
Tubes that are inserted inside arteries to keep them open making sure blood can pass through to the heart muscle
What do stents lower the risk of?
Heart attack in people with coronary heart disease
If you have a state what else do you have to take?
Drugs which stop the blood clotting
What is homeostasis?
The maintenance of a constant internal environment
What are the six main things that need to be controlled in the body?
- ) body temperature
- ) water content
- ) ion content
- ) blood sugar levels
- ) carbon dioxide
- ) urea
What to waste products need to be controlled in the body?
Carbon dioxide and urea
What is carbon dioxide a product of?
Respiration
What is urea made from?
Excess amino acids
Why must the body temperature be controlled for enzymes?
Enzymes within the human body work best at about 37c and so this temperature would be maintained
What in the brain tells us of we are too hot or cold?
The thermoregulatory centre
How does the thermoregulatory centre tell us if we are too hot or cold?
It contains receptors that are sensitive to the temperature of the blood flowing through the brain and it also receives impulses from the skin, giving info about skin temperature
What three things happens what you’re too hot?
- ) hairs lie flat
- ) sweat is produced by the sweat glands and evaporated from the skin removing heat
- ) blood vessels supplying the skin dilate
Why do your blood vessel supplying the skin dilate where you’re too hot?
So more blood flows close to the surface of the skin, making to easier for heat to he transferred from the blood to the environment
What four things happen when you are too cold?
- ) hairs stand up to trap am insulating layer of air
- ) no sweat is produced
- ) blood vessel supplying skin constrict to close off the skins blood supply
- ) when you’re cold you shiver
Why do you shiver when you’re cold?
During shivering your muscles contract automatically which needs more respiration which releases some energy to warm the body
What are the main three roles kidneys perform?
- ) removal of urea from the blood
- ) adjustment of ions in the blood
- ) adjustment of water content of the blood
How and where is urea formed?
Proteins can’t be stored by the body so any excess amino acids are converted into fats and carbohydrates, this process occurs in the liver and the urea is the water product from this
Is urine harmless to the body?
No it is poisonous
Where is urea temporarily stored?
In the bladder in urine
How do ions get into the body?
Taken into the body in food and the absorbed into the blood
What happens if the ion or water content of the body is wrong?
It will upset the balance between ions and water meaning too much or too little water is drawn into cells by osmosis, this can damage the cells so they don’t work as well as normal
How are excess ions removed by the kidneys?
By the kidney and some are lost in sweat
What is the three main ways the water is lost by the body?
In urine, in sweat and in the air we breath out
In what way does the body balance water content?
Balances the water coming in against the water going out
What ways in which water is lost can’t our body control?
The water we breath out
As we can’t control the water we breath out what three ways does out body control water balance?
In liquids consumed,ma mount sweated out, amount excreted by the kidneys in the urine
If you sweat a lot do you produce more or less urine?
Less
What do sports drinks replace?
The water and ions lost in sweat, and the sugar in it replaces sugar that is used up by muscles during exercise
What are the filtration units in the kidneys?
Nephrons
What happens during ultrafiltration in the kidneys ?
A high pressure is built up which squeezes water, urea, ions and sugar out of the blood and into the bowman’s capsule
During ultrafiltration why do big molecules stay in the blood?
The membrane between the blood vessel and the bowman’s capsule act like filters only letting smaller molecules through
What big molecules aren’t filtered out of the blood at the bowman’s capsule?
Proteins and blood cells
What small molecules are filtered out of the blood at the bowman’s capsule?
Water, urea, ions and sugar
What happens during reabsorption in a nephron?
As the liquid flows along the nephron useful substances are reabsorbed back into the blood
What is reabsorbed in the nephron?
All the sugar, and some water and ions
How is the sugar and ions reabsorbed in the nephron?
Through the process of active transport against the concentration gradient
In the nephron what are the waste substances that are released?
The remaining substances including urea, some water, some ions and some hormones
If someone’s kidney stops working what are the two treatments possible?
Regular dialysis or a transplant
What happens if your kidneys aren’t working properly?
Waste substances build up in your blood and you lose your ability to control the levels of ions and water in your body, which will result in death
Why does dialysis have to be regularly?
To keep the concentrations of dissolved substances in the blood at normal levels and to remove waste substances
What happens during dialysis?
The person blood flows alongside a selectively permeable membrane surrounded by dialysis fluid, it’s permeable so things like ions and waste substances can pass through, but not big molecules like proteins just like the bowman capsule. The waste substances like urea and excess ions and water diffuse across the barrier and leave the blood
Dialysis almost replaces the?
Kidney
What is in the dialysis fluid?
The same concentration of dissolved ions and glucose and healthy blood
How often do patients with kidney failure have to have dialysis and how long for?
Three times a week, each session takes 3-4 hours
What are two things that may be a bad side effect of dialysis?
Blood clots or infection
What is the only way at the moment to completely cure kidney disease?
Have a kidney transplant
What happens during a kidney transplant?
Healthy kidneys are usually transplanted from people who have died suddenly, like in a car crash, and who are on the organ donor register or carry a donor card into someone who has kidney failure. Kidneys can also be transplanted from people who are still alive as we have two
What happens if a donor kidney is rejected?
The patients immune system begins to attack the kidney, the foreign antigens on the donor kidney are attached by the patients antibodies
What two things are done to try and prevent kidneys being rejected?
- ) they make sure the donor has tissue type that closely matches the patient
- ) the patient is treated with drugs that suppress the immune system, so their immune system won’t attack the transplanted kidney
What’s a disadvantage of dialysis compared to a transplant?
Dialysis is very expensive compared to a transplant
What are two hormones involved with controlling blood glucose levels?
Insulin and glucagon
Eating food containing what puts glucose into the blood from the gut?
Carbohydrates
What usually removes glucose from the blood?
Normal metabolism of cells
What removes much more glucose from the blood than the normal metabolism of cells?
Vigorous exercise
Changes in glucose are monitored and controlled by what organ?
The pancreas
If blood glucose levels are too high what hormone is added?
Insulin
What does insulin make the liver do to glucose and how does this help blood glucose levels?
Turn glucose into glycogen reducing blood glucose levels
What hormone is added is blood glucose levels are too low?
Glucagon
What does glucagon make the liver do to glycogen and what is its effect on blood glucose level?
Glucagon makes the liver turn glycogen into glucose and so increasing the blood glucose levels
Does insulin reduce or increase blood glucose levels?
Reduce
What is type 1 diabetes?
Condition where the pancreas produces little or no insulin, the result is that a person blood glucose can rise to a level that can kill them
What are two ways that type 1 diabetes can be controlled?
- ) avoiding foods rich in simple carbohydrates
2. ) injecting insulin into the blood at mealtimes to make the liver remove the glucose stopping levels getting too high
What does the amount of insulin that needs to be injected depend on?
The persons diets me now active they are
Where did insulin used to be get from and where is it got from now?
It used to be extracted from the pancreases of pigs and cows but now human insulin is made by genetic engineering
Why is using human insulin better than using animal insulin to trade type 1 diabetes?
It doesn’t cause any adverse reactions
Other than injecting insulin how can type 1 dilates be cured
Have a pancreas transplant
