Unit 3 Flashcards
Define osmosis.
Diffusion of water from an area of high concentration to a low concentration through a partially permeable membrane.
What does membrane allow through?
Water molecules
What happens if we place a cell into pure water?
Water moves into the cell by osmosis.
What would happen if we placed a cell into a concentrated sugar solution?
Water would move out of the cell by osmosis
What do sports drinks contain? Why?
Water and ions to replace those lost in swear
Sugars to Roland those used in respiration for energy
What is a solvent?
Liquid like water
What is the solute?
Solid that dissolves in solvent (sugar)
What is active transport?
When substances are absorbed against the concentration gradient from low to high concentration.
What does active transport require? From what?
Energy from respiration
How is active transport different from diffusion?
Particles move against conc gradient
Requires energy
What are respiration inhibitors?
Poisons stop mitochondria from carrying out aerobic respiration
What does a respiration inhibitor do?
Reduces energy available to Cells causing active transport to slow and stop
Name some specialised exchange systems.
Small intestine
Lungs
What is found in the small intestine?
Villi
How does villi increase the rate of diffusion of food molecules in the small intestine?
Large surface area
Good blood supply = steep concentration gradient
Thin surface =faster diffusion
What happens in the lungs?
Gas exchange
What are the air sacs called in the lungs?
Alveoli
What happens inside the alveoli in the lungs?
- oxygen diffuses from air into blood stream
- oxygen into blood cells
- carbon dioxide diffused out of blood stream into air
How are alveoli adapted to increase diffusion?
Large surface area
Good blood supply = steep concentration gradient
Thin surface = faster diffusion
What is another word for breathing?
Ventilation
In what part of the body are the lungs found? What is this part called?
Upper body
Thorax
What is the lower part of the body called?
Abdomen
What muscle separates the thorax and abdomen?
Diaphragm
What are the lungs surrounded by?
Ribs
What is found in between the ribs?
Intercostal muscles
What happens during breathing?
Diaphragm and intercostal muscles work together to change the volume of the lungs
What happens when you inhale?
Diaphragm and intercostal muscles contract increasing lung volume
Pressure in Lungs decrease
Aid drawn into the lungs
What happens when we exhale?
Diaphragm and intercostal muscles relax decreasing lung volume
Pressure in lungs increase
Air is pushed out of the lungs
How to breathing aid the lungs ?
Keeps concentration gradient as high as possible -oxygen diffusion fast
Concentration gradient of co2 high as possible too
How does an iron lung work?
Forms an air tight seal around patients body (only head exposed)
Machine reduces air pressure in chamber and the lungs expand allowing air to rush in
Machine then increases pressure the lungs become smaller and air rushes out
Advantages and disadvantages of an iron lung?
Good-
Patient is conscious and can communicate
Not damadge airways
Bad-
Bulky and patient must be still
Patient breaths in normal air not extra oxygen
How does a bag ventilator work? What are they used for?
Face mask over mouth
Squeeze bag forces air into patients lungs
Emergencies
What are the advantages and disadvantages of modern artificial ventilators?
Good-
We use a high percentage of oxygen than normal air
It’s automatic and can change frequency of breathing
Bad-
Patient can’t communicate
Damage patients trachea
What does blood contain?
Plasma
Platelets
Red blood cells
White blood cells
What is the function of plasma?
Liquid which transports molecules round the body:
Soluble digestion products from small intestine to other organs
Carbon dioxide from organs to lungs after aerobic respiration
Waste urea from liver to kidneys to be passed out in urine
What do red blood cells do?
Transport oxygen from the lungs to the organs fro aerobic respiration. They contain oxygen carrying molecules called haemoglobin
How do red blood cells pass round oxygen?
In the lungs there’s a high concentration of oxygen
Oxygen diffuses into the red blood cells and combines with haemoglobin to form oxyhemoglobin.
Red blood cells now move out of the lungs to other organs (e.g. Liver) where concentration of oxygen is low
Oxyhemoglobin releases its oxygen
Oxygen diffuses into cells of organs
Used in aerobic respiration
What doe red blood cells not contain? Why?
No nucleus
Increase amount of haemoglobin meaning they can carry a lot of oxygen
What do white blood cells do?
Form part of the immune system
Defend body against microorganism (e.g. Bacteria)
What are platelets? What do they do?
Small fragments of cells with no nucleus
Help blog clot at site of a wound
What is the difference between fish and mammals circulatory system?
Fish have a single circulatory system
Mammals have a double circulatory system
Name a simple circulatory system for mammals
Lungs oygenated to heart to organs
Organs deoxygenated to heart to lungs
What is the heart made of?
Muscle tissue
What does the heart do?
Pump blood around the body
How many parts are there to the heart?
4 chambers
What do valves do?
Stop the blood from flowing backwards
Why does the left side of the heart have a thicker muscular wall?
The left ventricle pumps blood around entire body so needs to provide greater force
What is the structure of an artery and why?
Thick wall-cope with high pressure
Muscle and elastic fibres - cope with surges of blood that pass through artery as heart beats
How can arteries narrow? How can it be corrected?
Fatty substances build up in the artery walls
Insert a stent which keeps artery open
A stent is a small mesh tube
Why are stents used mainly in the coronary artery?
It supplies the heart muscles with blood and if it narrow the heart can be starved of oxygen
What is the structure of veins?why?
Thin wall- blood pressure is low
Valves- open when blood is flowing forward but close when it flows backwards
What is the structure of capillaries ?
Thin wall- substances diffuse easily between blood and body cells
What substances diffuse from blood to cells?
Glucose
Oxygen
What substances are produced by cells?
Carbon dioxide
What is the symbol equation for respiration?
C6H12O6 + 6O2
TO
6CO2 + 6H2O
What is the structure of a palisade cell starting from the top?
Epidermal cells Palisade mesophyll Spongy mesophyll Stomata Guard cells
What do the epidermal cells do in a plant?
Protect the leaf eg from fungus
What does the palisade mesophyll do?
Main site for photosynthesis packed full of chloroplasts
What does the spongy mesophyll do?
Allow diffusion of gases in the leaf because cells are loosely packet with air spaces between them
What does the stomata do?
Pores which allow gases to diffuse in and out of the leaf
How does photosynthesis occur in a palisade cell?
Carbon dioxide diffuses into leaf through stomata
Carbon dioxide diffuses through the spongy mesophyll up to palisade cells where it’s used in photosynthesis
Why is there a concentration gradient in palisade cells?
Palisade cells use carbon dioxide for photosynthesis and so there is a lower concentration at the top
How often do plants respire?
All the time?
When do plants photosynthesise?
In light conditions
How is the size of stomata controlled?
2 guard cells - guard cells change their shape
If plants need to reduce water loss they close their cells
How does water enter plants?
Water enters roots by osmosis
Root hair cells adapted to ensure lots of water is absorbed
water passes into xylem vessels makes its way up stem to the leaves
How are root hair cells adapted to increase water consumption?
Large SA
Use active transport to move ions into cell
Makes inside more concentrated by soil so makes water move in by osmosis
What do xylem do?
Water from roots to leaves
What is meant by a transpiration stream?
Movement of water fro the roots through xylem and out of the leaves
What does the phloem do?
Sugars and minerals from leaves to plant
What is homeostasis?
Keeping internal conditions in the body constant
What are the two main waist products made in the body?
Co2 removed by lungs
Urea produced by liver by breakdown of amino acids removed by bloodstream by kidneys and leaves body by urine
What happens if water and ion levels are controlled by the kidney?
Water can move in and out of cells by osmosis and can damage them
How is urea passed from blood out into urine?
Blood enters kidney containing urea
Kidney removed urea
Passes out as urine stored in bladder
How does the kidney removed molecules from the blood?
Blood pass through capillaries where small molecules are filtered out of blood (urea, glucose, ions, water)
All glucose + some ions and water re-absorbed back into blood
Urea +excess ions and water released in urine
How is urea produced by the liver?
Breakdown of amino acids from protein
How does kidney dialysis work?
Blood passes over semi permeable membrane
Only Small molecules like urea and water are allowed through
Dialysis fluid contains glucose in the same concentration found in blood
Concentration gradient of urea
Urea diffuses form blood into dialysis fluid
In kidney dialysis what is there bonnet movement of?
Useful substances like glucose
Why might a kidney transplant be rejected?
Cells of the donated kidney are covered in molecules(antigens) that the patients body sees as foreign.
Antigens attacked by antibodies in blood
How can scientists prevent kidney rejection?
Find kidney with closely matched tissue type
Treat patient with drugs which suppress immune system
What are the positives and negatives of kidney dialysis?
No shortage of machines
Expensive
Requires frequent treatments and strict diet
What are the advantages and disadvantages of kidney transplants?
Shortage of kidney donors
Patient must take immunosuppressive drugs for the rest of their life
Only expensive initially
Allows patient to live a normal life
What is our body temperature measured by in the body?
The brain (thermoregulatory centre)
How does the body respond to it being too hot?
Sweat glands release sweat onto the surface of the skin
Sweat evaporates taking energy from the body cooling it down
Blood vessels dilate (inflate)
More blood blows through capillaries and more heat is lost
How does the body respond to low temperatures ?
Blood vessels constrict (narrower)
Less blood flows through the capillaries and less heat is lost
Shivering makes muscles contract
To contract the muscles increase rate of respiration
Heat is released
Where does most glucose come from in our diet?
Starch
What is excess glucose stored as?
Glycogen in muscles and the liver
How is blood glucose controlled ?
After a meal blood glucose levels rise
Pancreas detects rise and releases hormone insulin
Insulin causes cells to take up more glucose
Glucose stored as glycogen
What happens to blood sugar levels between meals? How is it controlled?
Blood glucose levels fall
Pancreas detects fall and releases hormone glucagon
Glycogen converted back to glucose to be released into blood
Return to normal
what happens in type 1 diabetes ? How is it treated ?
Pancreas does not produce enough insulin
Blood glucose rises very high
Insulin injections
Diet and exercise
Why are rainforests cleared?
Wood
Grow crops do make ethanol for biofuels
Grazing cattle to provide beef
What are the negative effects of deforestation?
Loss of biodiversity
Carbon dioxide increases
Methane increases
Peat bogs
What are peat bogs? Why do people want them?
Formed from the remains of plants contain a lot of trapped carbon
Being stripped for compost releasing lots of carbon dioxide
What is carbon dioxide released by?
Burning fossil fuels
Deforestation
What is methane released by?
Cows
Rice fields
What does global warming lead to?
Changes in earths climate
Rising sea levels
Reduction in biodiversity
Changes in species distribution and migration patterns
How are biofuels made? How are they used ?
Food can be converted to ethanol by fermentation by using yeast.
Blend with petrol to make biofuel for cars
How is biogas formed?
Bacteria carry out anaerobic fermentation on carbohydrates such as left over food or manure from cows
Biogas is mainly methane
I hat is the difference between small scale and large scale biogas generation?
Small: -provide cooking fuel for families -can be next to source -temp must be warm (35^) so bacteria can repairs fast (too hot enzymes will not work) -has to be cleaned out Large: -provides large amount -optimum temp can be controlled electronically -can run continuously -may have to be transported
What chemicals are used in farming?
Fertilisers
Herbicides
Pesticides
What is mycoprotein?
Made of fungus (fusarium) which is suitable alternative to meat for vegetarians
