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287 Cards in this Set
- Front
- Back
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How do you calculate the surface area of a sphere? |
Back (Definition) |
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Doe heat need to be exchanged and why? |
Yes because the body needs to stay at one temperature |
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How to work out volume? |
Area times height |
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How to work out suface area? |
Work out area of each side and add it together |
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What do cells need? |
Oxygen and nutrients |
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What do cells need? |
Oxygen and nutrients |
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What so cell need to excrete? |
Urea and CO2 |
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How do substances get into single celled organisms? |
Diffuse straight into it, diffusion rate is quick |
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How do substances get into single celled organisms? |
Diffuse straight into it, diffusion rate is quick |
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Why is diffusion through an outer membrane in a multicelluar body too slow? |
Some cells are deep within a body Larger animals have a low SA:V |
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What do multicellular animals need to carry substances? |
Effiecent system |
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What do multicellular animals need to carry substances? |
Effiecent system |
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What is mass transport? |
Effiecent system to carry substances to and from their indivual cells. E.g. circulatory system |
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What does the circulatory system carry around? |
Glucose, oxygen, hormones, antibodies, and waste |
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How does body size affect heat exchange? |
Organism has a low SA:V ratio is loses heat slower(big animal) Organism had a large SA:V ratio it loses heat faster(small animal) |
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Why would a small animal need a high metaoblic rate in cold environment? |
To stay warm |
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How does body shape affect heat excahnge? |
Animals with a compact shape have a small SA:V so they lose heat slower |
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Describe behavioural adaptations to aid exchange? |
Eat more food to increase metabolic rate Large animals in hot environments spend time in water |
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Describe behavioural adaptations to aid exchange? |
Eat more food to increase metabolic rate Large animals in hot environments spend time in water |
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Describe other adaptations to aid excahnge? |
Kidney structure adaptations in the desert to stop water loss More fur in cold environments Flat ears in hot environments |
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How to work out the surface area of a sphere?? |
4pie r2 |
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How to work out volume of sphere? |
4/3pier3 |
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What do gas exchange surfaces have that increase the rate of diffusion? |
They have a large surface area Thin so provide a small diffusion pathway |
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Describe the structure of the gills? |
Water enters the mouth and passes out through the gills, Gills have small plates called gill filaments |
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What are gill filaments covered with? |
Small structures called lamellae which have lots of capillaries on it. |
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Explain the countercurrent sytem in the gills? |
Deoxygenated Blood flows through the lamellae in one direction and the water flows over the other. Water has a high O2 conc and blood has a low one. This means there is a steep conc gradient so oxygen moves into the blood |
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What is the gas exchange surface on plants? |
Mesophylk cells |
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What is the gas exchange surface on plants? |
Mesophylk cells |
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Why are mesophyll cells adapted well to gas exchange? |
Large surface area |
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How do gases move in and out of plants? |
Through the stomata |
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How do gases move in and out of plants? |
Through the stomata |
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What happens to the stomata if the plant is losing too much water? |
Closes |
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What controls the opening and closing of the stomata? |
Guard cells |
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Explain the gas exchange surface on the insects? |
Air moves into the trachea, through pores called spiracles. Oxygen travels down its concentration gradient. The trachea branch off into smaller tracheoles, which have thin permeable walls which go the cells. |
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Explain the gas exchange surface on the insects? |
Air moves into the trachea, through pores called spiracles. Oxygen travels down its concentration gradient. The trachea branch off into smaller tracheoles, which have thin permeable walls which go the cells. |
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How does an insect release gases? |
CO2 moves down its own conc gradient towards the spiracles to be realeased into the atmosphere. |
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What do insects do to move air in and out of the spiracles? |
Rhymic abdominal movements |
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What do insects do if they lose too much water? |
Close their spiracles using muscles, they also have waterprood waxy cuticle all over their body Tiny hairs around the spiracles reduces water loss |
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What happens to guard cells when water enters? |
Makes them turgid which opens the stomata |
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What happens to the guard cells if it loses too much water? |
Become flaccud which closes the pore |
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What happens to the guard cells if it loses too much water? |
Become flaccud which closes the pore |
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What is the name of plants which are well adapted to warm, dry or windy habitats where water loss is a problem? |
Xerophytes |
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What happens to the guard cells if it loses too much water? |
Become flaccud which closes the pore |
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What is the name of plants which are well adapted to warm, dry or windy habitats where water loss is a problem? |
Xerophytes |
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Give examples of xerophytic adaptations? |
Stomata sink in outs to trap water vapour, reducing conc gradient of watee between leaf and air, therefore reducing evaporation Layer of hairs on the epidermis to trap water vapour Curled leaves with stomata on the inside, protecting them deom wind to stop evaportion Reduced number of stomata Thicher waxy waterproof cuticles on leaves and stem to reduce evaporation |
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How does air get into your bloodstream? |
As you breathe in air enters the trachea, trachea then splits in the bronchi, one bronchus then leads to each lung. The bronchus then branches off to the bronchioles then to the alveoli, the gas is exchanged. |
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How many intercostal muscles are there? |
There are the internal and external. |
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What does ventilation consist of? |
Inspiration and expiration |
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What is ventilation controlled by? |
Diaphragm, internal and external intercostal muscles and the ribcage |
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What happens during inspiration? |
The external intercostal and diagphram contract. This causes the ribcage to move upwards and outwards. The diaphragm then flattens, increasing the volume of the thorativ cavity. As the thoratic cavity increases, the lung pressure decreases to below atmospheric pressure. Air then flows down the pressure gradient into the lungs. |
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Is inspiration a passive or active process? |
Active |
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What happens during expiration? |
External intercostal muscles and the diaphragm relax. The ribcage moves downwards and inwards, and the diaphragm curves inwards The volume of the thoratic cavity decreases, causing aur pressure to inc above atmospheric pressure.Air is then forced down the pressure gradient and out of the lungs. |
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Is normal expiration passive or active process? |
Passive |
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What happens during forced expiration? |
External intercostal muscles relax and the internal one contracts. Pulling the ribcage further down and in. |
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Describe the structure of alveoli? |
Back (Definition) Avelolar space, avelolar epithelium, capillary endothelium and the blood capillary |
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What do the walls of the alveoli have which helps them? |
Protein called elastin, it helps alveoli return to its normal shape after inhailing and exhailing air |
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What gradient does oxygen move down when it goes into the blood? |
Diffusion gradient |
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What gradients does CO2 move down to leave the body? |
Its own diffusion and pressure gardient, but in the opposite direction to oxygen |
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Explain gas exchange in the alveoli? |
Oxygen diffuses out of the alveoli, across the alveolar epithliuem and the capillary endothelium and into haemoglobin. CO2 moves out of the blood into the alveoli. |
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When oxygen is in the air going towards the alveoli what is the gradient called? |
Pressure |
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What is the gradient called when oxygen is in the alveoli going into haemoglobin? |
Diffusion |
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Factors affecting rate of diffusion in gas exchange(alveoli)? |
Thin exchnage surface- alveolar apithelium only one cell thick. Large surface area- millions of alveoli Steep conc gradient between O2 and CO2 between the alveoli and the capillaries |
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Definition of tidal volume? |
The volume of air in each breathe |
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Definition of tidal volume? |
The volume of air in each breathe |
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Definition of ventilation rate? |
Number of breaths per minute |
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Definition of forces expiratory volume1? |
Maximum volume of air that can be breathed out in 1 second |
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Definition of forced vital capacity? |
Maximum volume of air it is possible to breathe forcefully out after a deep breathe in. |
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Explain tuberculosis? |
Caused by bacteria, when someone becomes infected the immune system cells build a wall around the bacteria in the lungs. Causing small hard lumps known as tubercles. The infected tissue dies and small hard lumps form damaging the exchange surface. Tidal volume decreases which means an inc in ventilation rate. |
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Explain fibrosis? |
Formation of scar tissue on the lungs. Can be a result of exposure go dust etc. Scar tissue is thicker and less elastic than normal lung tissue. Lungs cant expand as much and cannot hokd as much. Tidal volume is decreased and so is FVC. Reduction in the rate of gaseous exchange as diffusion is slower across a thicker scarred membrane. |
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Explain fibrosis? |
Formation of scar tissue on the lungs. Can be a result of exposure go dust etc. Scar tissue is thicker and less elastic than normal lung tissue. Lungs cant expand as much and cannot hokd as much. Tidal volume is decreased and so is FVC. Reduction in the rate of gaseous exchange as diffusion is slower across a thicker scarred membrane. |
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Explain asthma? |
Airways become inflamed and irritates. Usually caused by an allergic reaction to pollen and dust. During an asthma attack the smooth muscle lining of the bronchioles contracts and large amounts of mucus are released. This constricts the airways and makes it harder to breathe. |
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Explain fibrosis? |
Formation of scar tissue on the lungs. Can be a result of exposure go dust etc. Scar tissue is thicker and less elastic than normal lung tissue. Lungs cant expand as much and cannot hokd as much. Tidal volume is decreased and so is FVC. Reduction in the rate of gaseous exchange as diffusion is slower across a thicker scarred membrane. |
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Explain asthma? |
Airways become inflamed and irritates. Usually caused by an allergic reaction to pollen and dust. During an asthma attack the smooth muscle lining of the bronchioles contracts and large amounts of mucus are released. This constricts the airways and makes it harder to breathe. |
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Describe emphysema? |
Lung disease caused by smoking or long term exposure to air pollution. Foreign particle sor smoke are trapped in the alveoli. This causes inflammation which attracts phagocytes. The phagocyte produces an enzyme which breaks down elastin in the walls of the alveoli. Loss of this means it cant expell air as well. And destroys the alveoli walls which reduces surface area |
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Effect of lung diseases on gas exchange? |
Reduces the rate Body cells recieve less oxygen so rate of aerobic respiration is reduced. Less energy is released so suffers feel tired. |
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When interpreting data on kung diseases what is a correlation? |
Link between two things e.g. if you smoke you are more likely to get lung cancer |
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When interpreting data on kung diseases what is a correlation? |
Link between two things e.g. if you smoke you are more likely to get lung cancer |
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One thing to look out for if you see a correlation? |
The correlation doesnt always mean it causes it |
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What should you do when interpreting data on lung diseases? |
Describe the data Draw conclusions- correlation dont say cause. Other points to consider- |
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How do you respond to experimental data? |
Look at all factors and evidence then conclude |
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What happens during digestion? |
Large molecules are broken down into smaller ones via hydrolysis and then moves across the cell membrane |
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What do digestive enzymes do? |
Break down biological molecules in food.specific to one food molecule |
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What does amylase do? |
Breaks down down starch via hydrolysing the glycosidic bonds to produce maltose |
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What does amylase do? |
Breaks down down starch via hydrolysing the glycosidic bonds to produce maltose |
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Where is amylase produced? |
Salivary glands and pancreas |
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What do membrane bound disaccharides do? |
Enzymes attached to cell membranes of the epithlial cells lining the ileum. They break down disaccharides to monosacharides |
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What does lipase do? |
Catalyse breakdown of lipids into monoglycerides and fatty acids. Hydrolyse the ester bonds in lipids. |
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What does lipase do? |
Catalyse breakdown of lipids into monoglycerides and fatty acids. Hydrolyse the ester bonds in lipids. |
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Where are lipases made and where do they work? |
Made in the pancreas and secreted into the small intestine. |
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What do bile salts do? |
They emulsify lipids, cause them to make smaller droplets. Increase the surface area of the droplets for lipases to work on |
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What do bile salts do? |
They emulsify lipids, cause them to make smaller droplets. Increase the surface area of the droplets for lipases to work on |
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Where are bile salts made? |
Liver |
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What are micelles and what is their purpose? |
they are monoglycerides and fatty acids stuck to the bile salts. Help lipid digestion |
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What are proteins broken down by? |
Combination of endopeptidases and exopeptidases and dipeptidaeses |
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How do peptidases break down proteins? |
Hydrolysing the peotide bonds |
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What do endopeptidases hydrolyse? |
Hydolyse the peotide bonds on the inside of the protein chain |
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What do exopeptidases hydrolyse? |
The outside of the polypeptide chain |
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What do dipeptides do? |
Hydolyse dipeptides into an amino acids. |
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Where are peptidases released and made? |
Some in the pancreas and used in the small intestine Some in the stomach and released into the stomach Dipeptidase work in the si |
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How are monosacharides absorbed? |
Active transport with the sodium ions via the co transporter Galaxtose the same way Fructose vis facilitated diffusion |
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How are monoglycerides and fatty acids absorbed? |
Micelees help move them towards the epithelium. Micelles break off and they diffuse across the membrane |
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How are amino acids absorbed? |
Via a co transporter |
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What does haemoglobin do? |
Carry O2 around the body |
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What does haemoglobin do? |
Carry O2 around the body |
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Is their chemically similar haemoglobin many differnt organisms? |
Yes |
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What structure does haemoglobin have? |
Quaternary |
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Haemoglobin is made up of 4 polypeptide chains, what is attached to the chain? |
Haem group attached to each one |
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What does a haem group contain and what colour does it give the haemoglobin? |
An iron ion and it gives it a red colour |
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What does a haem group contain and what colour does it give the haemoglobin? |
An iron ion and it gives it a red colour |
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How many oxygen molecules can haemoglobin carry? |
4 |
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When oxygen joins to haemoglobin what does it form? |
Oxyhaemoglobin |
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When oxygen joins to haemoglobin what does it form? |
Oxyhaemoglobin |
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Is the reaction between haemoglobin and oxygen reversible and why? |
Yes because it has to release oxygen to respiring tissues |
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What is it called when oxygen joins to haemoglobin? |
Association |
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What is it called when oxygen joins to haemoglobin? |
Association |
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What is it called when oxygen leaves haemoglobin? |
Dissociation or unloading |
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What is it called when oxygen joins to haemoglobin? |
Association |
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What is it called when oxygen leaves haemoglobin? |
Dissociation or unloading |
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Equation for haemoglibg + oxygen? |
Hb + 4O2 <-> HbO8 |
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What does oxygena affinity mean? |
The tendency a molecule has to bind with oxygen |
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What conditions affects haemoglobins affinity for oxygen? |
Partial pressure of oxygen (pO2) |
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What is pO2 a measure of? |
Oxygen concentration |
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What does oxygen do when pO2 is high? |
Loads onto haemoglobin |
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What does oxygen do when pO2 is low? |
Unloads |
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If at the alveoli the O2 conc is high what happens? |
High pO2 and high affinity so oxygen will load onto haemoglobin |
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If the oxygen conc is low at the respiring tissues what happens? |
Low pO2 and low affinity so oxygen unloads |
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What does an oxygen dissociation curve show? |
Shows how saturated haemoglobin is with oxygen at any given partial pressure |
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What do the high and low points on an O2 curve show? |
High (e.g.lungs) shows high affinity ao it has a high saturation of oxygen Low (e.g. respiring tissues)is where it has a low affinity for oxygen, so it has a low saturation of oxygen. |
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What does the slow curve on the dissociation curve show? |
Hard for O2 molecules to load on |
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What does the slow curve on the dissociation curve show? |
Hard for O2 molecules to load on |
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What does the first oxygen binding to the haemoglobin and how does this affect the dissociation curve? |
Its shape alter so it is easier for more O2 to bind It cause the curve to become more steeper which shows that it is easy for oxygen to bind |
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Definition of pCO2? |
Measure CO2 conc in a cell |
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Definition of pCO2? |
Measure CO2 conc in a cell |
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How does pCO2 affect oxygen unloading? |
Haemoglobin give oxygen up more at higher pCO2 |
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What happens to the dissociation curve pCO2 and what is the bohr affect? |
When pCO2 is high the curve shifts right but does not cahnge shape. Bohr effect/ saturation of Blood with oxygen is lower for a given pO2, meaning more oxygen is released |
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In dissociation curves if the curve is more left what does that show? |
Higher affinty for oxygen |
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Function of the curculatory system? |
Multicellualr organisms have a low SA:V ratio, so they need a specialised system to carry raw materials to exchange organs |
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What carries blood from the heart to the lungs? |
Pulmonary artery |
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What carries blood from the lungs to the heart? |
Pulmonary vein |
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What carries blood from the heart to the body? |
Aorta |
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What carries blood from the body to the heart? |
Vena carva |
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What carries blood from the body to the kidneys? |
Renal artery |
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What carries blood from the kidneys tonthe vena carva |
Renal vein |
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What does blood transport? |
Products lf digestion Metabolic wates Hormones |
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What does blood transport? |
Products lf digestion Metabolic wates Hormones |
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What are the two circuits of the circulatory system? |
Blood from heart to lungs then back round. The other takes blood round the whole body |
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The hearts has its own bloodys supply what is it called? |
Left and right coronary arteries |
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What sort of blood does the vena carva carry to the heart? |
Deoxygenated |
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What sort of blood does the aorta transport to the body? |
Oxygenated |
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What sort of blood does the pulmonary artery transport to the lungs? |
Deoxygenated |
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What does blood always flow from to? |
High pressure to low pressure |
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What do arteries do? |
Carry blood from the heart to the rest of the body |
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Describe the structure of arteries? |
Walls are thick and muscular Elastic tissue to stretch and recoil as the heart beats, which helps maintain high pressure Innner lining is the folded endothelium allowing it to stretch, helps maintain high pressure |
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Describe the structure of arteries? |
Walls are thick and muscular Elastic tissue to stretch and recoil as the heart beats, which helps maintain high pressure Innner lining is the folded endothelium allowing it to stretch, helps maintain high pressure |
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What blood do arteries usually carry? |
Oxygenated blood |
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Describe the structure of arteries? |
Walls are thick and muscular Elastic tissue to stretch and recoil as the heart beats, which helps maintain high pressure Innner lining is the folded endothelium allowing it to stretch, helps maintain high pressure |
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What blood do arteries usually carry? |
Oxygenated blood |
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What is the one artery that carries deoxygenated blood and where to? |
Pulmonary artery Heart to lungs |
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What is an arteriole? |
Arteries divided in to smaller vessels |
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Why do arteries divide into smaller vessels? |
Because blood is needed in different areas of the body with different demands |
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Arteries have circular muscles how does that help them? |
To help the blood get to different areas by contracting or restrict |
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What do veins do? |
Take blood back to the heart under low pressure |
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What do veins do? |
Take blood back to the heart under low pressure |
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How do veins structure support its function? |
Wider lumen than arteries with little elastic or muscle tissue. Also contain valves to stop backflow, as it is under low pressure |
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What is blood flow through the veins helped by? |
Contraction if body muscles around the body |
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What do cells take in from the tissue fluid and release? |
Take in oxygen and nutrients Release metabolic waste into the fluid |
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What make the substances move out of the capillaries into the tissue fluid? |
Pressure filtration |
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Explain how tissue fluid is made and how hydrostatic pressure changes? |
At the start of the capillary bed, nearest the arteries, hydrostatic pressure in the capillaries is greater than that in the tissue fluid. The differnce means an outward force into into the spaces around the cell forming tissue fluid. As fluid leaves the hydostatic pressure reduces in the capillaries, so it is lower at the venule end of the capillary bed. |
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What blood do veins usually carry? |
Depxygenated blood |
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What vein carries oxygenated blood and where to? |
Pulmonary vein and from the lungs to the heart |
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What do capillaries branch from? |
Aterioles |
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Why do capilaries being so small and one cell thick help them? |
To allow substances to diffuse out of them easier in exchange tissues |
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Explain how capillaries structuee helps its function? |
One cell thick, large SA and always found near exchange tissues which make the diffusion pathway shorter Thus helps exchange |
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What is networks of tissues called? |
Capillary bed |
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Why does pressure decrease along a blood vessel? |
Due to friction |
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What is blood plasma? |
Liquid that carries everything in the blood |
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What is tissue fluid and what makes it? |
Its the fluid that surround cells in tissues Made from small molecules that leave the blood plasma, e.g. oxygen,water and nuttients small proteins |
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Explain the change in water potential across the capillary bed and what that causes? |
Due to fluid loss and an increasing amount of plasma proteins, the water potential at the venule end is lower than in the water potential in the tissue fluid. This means that some water re enters the capillaries, from the tissue fluid at the venule end. |
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What happens to any excess tissue fluid? |
Drained off into the lymphatic system, which transports it back into the circulatory system. |
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What can high blood pressure do to your tissue fluid? |
Causes a higher hydrostatic pressure in the capillaries, which can lead to an accumulation of tissue fluid in tissues. |
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Describe the structure of the heart? |
Oxygenated on right Deoxygenated on the left |
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How is the left ventricle adapted to its job? |
Thicker and more muscular walls than the right ventricle. This allows it to contract more powerfully and pump blood all the way round the body |
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How is the left ventricle adapted to its job? |
Thicker and more muscular walls than the right ventricle. This allows it to contract more powerfully and pump blood all the way round the body |
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Why is the right ventricle less muscular? |
It only has to transport blood to the lungs |
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Why does the atria have less muscular walls than the ventricles? |
Atria only transports blood into the ventricles |
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Why is the atrioventricular valve so important? |
Link the atria to the ventricles and stop blood flowing back into the atria when the ventricles contract |
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Why is the semi lunar valve so important? |
Link the ventricles to the pulmonary artery and the aorta, so stop backflow into the heart after the ventricles contract |
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Why are the cords important? |
Attach the AV valves to the ventricles, to stop thek being forces into the atria when the venticles contract |
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Do valves only open one way? |
Yes |
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If there is higher pressure behind the valve what happens? |
It opens |
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What happens if the pressure is higher infront of the valve? |
It shuts |
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How to carry out a heart dissection? |
Should be a pig or cow heart |
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Explain the first part of the cardia cycle? |
Ventricles relax and atria contract Dec vol in chamber and inc pressure, this pushes blood into the ventricles. Slight inc in ventricular pressure and chamber vol as the ventricles recieve ejected blood from the atria |
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Explain the second part of the cardiac cycle? |
Atria relax, ventricles contract Decreasing volume and increasing pressure The pressure is higher in the ventricles than the atria which forces the AV valves shut to stop back flow Pressure is higher than that in the aorta and pulmonary artery which forces the SL valves open and blood is forced out. |
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Explain the third part of the cardiac cycle? |
Both ventricles and atria relax The higher pressure in the pulmonary artery and the aorta closes the SL valves to prevent backflow into the ventricles Blood returns to the heart and the atria fill again due to high pressure in the vena carva and pulmonary vein. This inc pressure of atria, as ventricles relax, their pressure falls below the one of the ventricle, this causes the AV valves to open. This allows blood to flow passively into the ventricles , then the atria contract. |
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Equation for cardiac output and units? |
Cardiac output(cm3 min-1)=stroke volume(cm3) x heart rate(bpm) |
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What is a cardiovascular disease? |
Disease associated with the heart and blood vessels |
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What can high blood pressure be caused by and what can it cause? |
Caused by: not a excercising or being over weight, alcohol etc Can cause: damaged artery walls, atheroma formation, blood clots, myocardinak infarction |
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What causes high blood cholesterol and what can it cause? |
Caused by: diet high in saturated fat causes it Causes : arethroma formation, blood clots and myocardinal infraction. |
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What causes high blood cholesterol and what can it cause? |
Caused by: diet high in saturated fat causes it Causes : arethroma formation, blood clots and myocardinal infraction. |
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What does a diet high in salt cause? |
High blood pressure, artheroma formation, blood clots and myocardial infraction |
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What can smoking cause? |
Carbon monoxide causes less oxygen in the blood so less oxygen gets to tissues which can cause myocardial infraction. |
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What can smoking cause? |
Carbon monoxide causes less oxygen in the blood so less oxygen gets to tissues which can cause myocardial infraction. |
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Smoking leads to fewer antioxidants in the blood, what can this cause? |
Causes damage to coronary artery walls as less antioxidants means more cell damage,this leads to an atheroma formation then to a myocardial infraction |
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What can reduce the risk of CD disease? |
Choose not to smoke, ear fatty food. |
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What can reduce the risk of CD disease? |
Choose not to smoke, ear fatty food. |
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How can the risk of CD not be reduced? |
Genetic predisposition to heart disease or high blood pressure. Diabeties from genetics. |
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When interpreting risk factors for CD what should you taln about? |
Describe the data, draw conclusions, check if the conclusions are valid, Talk about things like samole size etc |
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Why does temperature affcet transpiration rate? |
Warmer molecules have more energy so evaporate from the cells faster. This increases the water potential gradient between the inside and outside of the leaf, making water diffuse out of the leaf. So higher temperature increased rate of transpiration |
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|
Why does humidity affect the rate of transpiration? |
Lower the humidity, the faster the transpiration rate. If the air around the plant is dry, so the water potential gradient between leaf and air is inc so rate of transpiration is inc. |
|
|
Why does wind increase the rate of transpiration? |
The windier it is, the faster the transpiration rate. Lots of air movement blows away the water molecules from around the stomata, this increases the rate of transpiration. |
|
|
What does a potometer do? |
Tests different factors on transpiration rate. E.g. fan |
|
|
How do you work out the rate of uptake in a potometer? |
(MM3 per minute) you need to measure the distance moved by the bubble per minute and the diameter of the capillary tube. |
|
|
Structure of a phloem? |
Cells arranged in tubes,with sieve tubes snd companion cells |
|
|
Explain the function of sieve tube elements? |
Sieve tube elements are living cells that form the tube for transporting solutes. |
|
|
Explain the function of companion cells? |
The companion cell for each sieve tube element. They carry out the living functions for sieve cells. E.g. providing energy for active transport of |
|
|
Definition of translocation? |
Movement of solutes to where theyre needed in a plant. |
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|
Is translocation an energy requiring process True or false? |
True |
|
|
When intepreting risk factors on CD and you have conflicting evidence what should you talk about? |
Think sbout why theyre concluding, Was it to do with study design, based in sample size, did both studies take into account all risk factors, similar age or gender? Colkect more |
|
|
What is the source in translocation? |
Where assimilates( solutes) are produces High conc here |
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|
What is the sink in translocation? |
Where assimilates are used up (Lower conc here) |
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|
Assimilates move down a conc gradient from the source to the sink How is the conc gardient maintained? |
Enzymes maintain a conc gradient from the source to the sink by changing solutes at the sink (breaking them or making something new) This makes sure there is a lower conc at the sink than the source |
|
|
Explain the source part of the mass flow hypothesis? |
Active transport is used to actively load solutes , from companion cells into the sieve tube at the source. This lowers water potential inside the sieve tubes, so water enters the tubes by osmosis from the xylem and companion cells. This creates high pressure inside the source end. |
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|
What does CHD stand for? |
Coronary heart disease |
|
|
Describe what the xylem does and describe where it goes? |
Tissue transports water and mineral ions in solution. These substances move up the plant from roots to leaves. |
|
|
Describe what the phloem carries and where it goes? |
Transporta organis substance like sugars . Up and down the plant |
|
|
Describe the structure of the xylem? |
Long tube structures formed from dead cells,no end walls between cells. Tube is uninterupted. |
|
|
Describe the cohesion- tension theory? |
1. Water evaportes from the leaves at the top of the xylem via transpiration. 2. This creates tension which pulls more water into the leaf 3.because water molecules are cohesive, when some move up more follow.so a whole colluk moves up |
|
|
What is transpiration? |
Evaporation of water from the plants surface. |
|
|
How does water move out via transpiration? |
Water evaporates from moist cell walls and accumulates in the spaces between cells in the leaf. When the stomata opens, water moves out of the leaf down the water potential gardient. |
|
|
Why does light intensity affect rate transpiration? |
The lighter it is the faster the transpiration rate. This is because the stomata opens when it gets light to let in CO2 for photosynthesis. When its dark the stomata is usually closed so little transpiration. |
|
|
When interpreting risk factors for CD what should you taln about? |
Describe the data, draw conclusions, check if the conclusions are valid, Talk about things like samole size etc |
|
|
Why does temperature affcet transpiration rate? |
Warmer molecules have more energy so evaporate from the cells faster. This increases the water potential gradient between the inside and outside of the leaf, making water diffuse out of the leaf. So higher temperature increased rate of transpiration |
|
|
Why does humidity affect the rate of transpiration? |
Lower the humidity, the faster the transpiration rate. If the air around the plant is dry, so the water potential gradient between leaf and air is inc so rate of transpiration is inc. |
|
|
Why does wind increase the rate of transpiration? |
The windier it is, the faster the transpiration rate. Lots of air movement blows away the water molecules from around the stomata, this increases the rate of transpiration. |
|
|
What does a potometer do? |
Tests different factors on transpiration rate. E.g. fan |
|
|
How do you work out the rate of uptake in a potometer? |
(MM3 per minute) you need to measure the distance moved by the bubble per minute and the diameter of the capillary tube. |
|
|
Structure of a phloem? |
Cells arranged in tubes,with sieve tubes snd companion cells |
|
|
Explain the function of sieve tube elements? |
Sieve tube elements are living cells that form the tube for transporting solutes. |
|
|
Explain the function of companion cells? |
The companion cell for each sieve tube element. They carry out the living functions for sieve cells. E.g. providing energy for active transport of |
|
|
Definition of translocation? |
Movement of solutes to where theyre needed in a plant. |
|
|
Is translocation an energy requiring process True or false? |
True |
|
|
When intepreting risk factors on CD and you have conflicting evidence what should you talk about? |
Think sbout why theyre concluding, Was it to do with study design, based in sample size, did both studies take into account all risk factors, similar age or gender? Colkect more |
|
|
What is the source in translocation? |
Where assimilates( solutes) are produces High conc here |
|
|
What is the sink in translocation? |
Where assimilates are used up (Lower conc here) |
|
|
Assimilates move down a conc gradient from the source to the sink How is the conc gardient maintained? |
Enzymes maintain a conc gradient from the source to the sink by changing solutes at the sink (breaking them or making something new) This makes sure there is a lower conc at the sink than the source |
|
|
Explain the source part of the mass flow hypothesis? |
Active transport is used to actively load solutes , from companion cells into the sieve tube at the source. This lowers water potential inside the sieve tubes, so water enters the tubes by osmosis from the xylem and companion cells. This creates high pressure inside the source end. |
|
|
Explain the sink part of the mass flow hypothesis? |
Solutes are removed from the phloem to be used up. This increases water potential inside the sieve tubes. So water leaves the tubes via osmosis. This lowers the pressure inside the tubes. |
|
|
What does CHD stand for? |
Coronary heart disease |
|
|
Describe what the xylem does and describe where it goes? |
Tissue transports water and mineral ions in solution. These substances move up the plant from roots to leaves. |
|
|
Describe what the phloem carries and where it goes? |
Transporta organis substance like sugars . Up and down the plant |
|
|
Describe the structure of the xylem? |
Long tube structures formed from dead cells,no end walls between cells. Tube is uninterupted. |
|
|
Describe the cohesion- tension theory? |
1. Water evaportes from the leaves at the top of the xylem via transpiration. 2. This creates tension which pulls more water into the leaf 3.because water molecules are cohesive, when some move up more follow.so a whole colluk moves up |
|
|
What is transpiration? |
Evaporation of water from the plants surface. |
|
|
How does water move out via transpiration? |
Water evaporates from moist cell walls and accumulates in the spaces between cells in the leaf. When the stomata opens, water moves out of the leaf down the water potential gardient. |
|
|
Why does light intensity affect rate transpiration? |
The lighter it is the faster the transpiration rate. This is because the stomata opens when it gets light to let in CO2 for photosynthesis. When its dark the stomata is usually closed so little transpiration. |
|
|
When interpreting risk factors for CD what should you taln about? |
Describe the data, draw conclusions, check if the conclusions are valid, Talk about things like samole size etc |
|
|
Why does temperature affcet transpiration rate? |
Warmer molecules have more energy so evaporate from the cells faster. This increases the water potential gradient between the inside and outside of the leaf, making water diffuse out of the leaf. So higher temperature increased rate of transpiration |
|
|
Why does humidity affect the rate of transpiration? |
Lower the humidity, the faster the transpiration rate. If the air around the plant is dry, so the water potential gradient between leaf and air is inc so rate of transpiration is inc. |
|
|
Why does wind increase the rate of transpiration? |
The windier it is, the faster the transpiration rate. Lots of air movement blows away the water molecules from around the stomata, this increases the rate of transpiration. |
|
|
What does a potometer do? |
Tests different factors on transpiration rate. E.g. fan |
|
|
How do you work out the rate of uptake in a potometer? |
(MM3 per minute) you need to measure the distance moved by the bubble per minute and the diameter of the capillary tube. |
|
|
Structure of a phloem? |
Cells arranged in tubes,with sieve tubes snd companion cells |
|
|
Explain the function of sieve tube elements? |
Sieve tube elements are living cells that form the tube for transporting solutes. |
|
|
Explain the function of companion cells? |
The companion cell for each sieve tube element. They carry out the living functions for sieve cells. E.g. providing energy for active transport of |
|
|
Definition of translocation? |
Movement of solutes to where theyre needed in a plant. |
|
|
Is translocation an energy requiring process True or false? |
True |
|
|
When intepreting risk factors on CD and you have conflicting evidence what should you talk about? |
Think sbout why theyre concluding, Was it to do with study design, based in sample size, did both studies take into account all risk factors, similar age or gender? Colkect more |
|
|
What is the source in translocation? |
Where assimilates( solutes) are produces High conc here |
|
|
What is the sink in translocation? |
Where assimilates are used up (Lower conc here) |
|
|
Assimilates move down a conc gradient from the source to the sink How is the conc gardient maintained? |
Enzymes maintain a conc gradient from the source to the sink by changing solutes at the sink (breaking them or making something new) This makes sure there is a lower conc at the sink than the source |
|
|
Explain the source part of the mass flow hypothesis? |
Active transport is used to actively load solutes , from companion cells into the sieve tube at the source. This lowers water potential inside the sieve tubes, so water enters the tubes by osmosis from the xylem and companion cells. This creates high pressure inside the source end. |
|
|
Explain the sink part of the mass flow hypothesis? |
Solutes are removed from the phloem to be used up. This increases water potential inside the sieve tubes. So water leaves the tubes via osmosis. This lowers the pressure inside the tubes. |
|
|
Explain the flow part of the mass flow hypothesis? |
The result is a pressure gradient from source to sink. This pushes solites along sieve tubes to the sink. When they reach the sink the solutes are used e.g. respiration or stored e.g. stored |
|
|
If there is a higher conc of sucrose at the source what happens to the rate of tanslocation? |
Higher rate |
|
|
Companion cells have an organelle which helps them how does it and why? |
Lots of Mitochondria which means they can make lots of ATP. Which is needed to actuvely load solutes into the phloem. |
|
|
What evidence support the mass flow hypothesis? |
A radioactive tracer (C14) can be used to track the movement of organic substances in a plant. If a ring of bark is removed from a woody stem, a buldge from around the stem. The fluid in the buldge has a higher conc of sugars in it thsn the fluid below the ring.this is because the sufars cannot move past the area. This is evidence that ther can be a downward flow of sugars. |
|
|
What shows that the mass flow hypothesis is false? |
Sugar travles to many differnt sinks, not just the one with the highest water potential as the model would say. The sieve plates would create a barrier to it, a lot of pressure would be needed for them to get through at a good rate. |
|
|
What does CHD stand for? |
Coronary heart disease |
|
|
Why would sugars move down? |
They are mass in the leaves |
|
|
Describe what the xylem does and describe where it goes? |
Tissue transports water and mineral ions in solution. These substances move up the plant from roots to leaves. |
|
|
Describe what the phloem carries and where it goes? |
Transporta organis substance like sugars . Up and down the plant |
|
|
Describe the structure of the xylem? |
Long tube structures formed from dead cells,no end walls between cells. Tube is uninterupted. |
|
|
Describe the cohesion- tension theory? |
1. Water evaportes from the leaves at the top of the xylem via transpiration. 2. This creates tension which pulls more water into the leaf 3.because water molecules are cohesive, when some move up more follow.so a whole colluk moves up |
|
|
What is transpiration? |
Evaporation of water from the plants surface. |
|
|
How does water move out via transpiration? |
Water evaporates from moist cell walls and accumulates in the spaces between cells in the leaf. When the stomata opens, water moves out of the leaf down the water potential gardient. |
|
|
Why does light intensity affect rate transpiration? |
The lighter it is the faster the transpiration rate. This is because the stomata opens when it gets light to let in CO2 for photosynthesis. When its dark the stomata is usually closed so little transpiration. |
