Biology Topics, 9, 10, 11, 12, 13

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T9- What four mineral ions do plants require?
Nitrates, Phosphates, potassium and magnesium in smaller amounts.
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T9- Why do plants need nitrates?
they contain nitrogen which is essential to make maino acids and therefore proteins. They need it to grow and without it, the plant will be stunted with yellow leaves.
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T9- Why do plants need Phosphates?
they contain phosphorus which is essential for making DNA and cell membranes. Therefore it is needed for respiration and growth, and without it there is poor growth/purple leaves.
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T9- Why do plants need potassium?
Potassium helps the enzymes needed for photosynthesis and respiration. Without it there is poor fruit growth and discoloured leaves.
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T9- describe how magnesium is needed.
It is needed in much smaller amounts and is required to make chlorophyll for photosynthesis. Without it the leaves would be yellow.
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T10- Why do unicellular and multicellular organisms need the transport systems that they have?
Unicellular- gases can directly diffuse in and out from the cell membranes. Multicellular- transport systems required as diffusion across from surface cells would be too slow.
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T10- What is the role of the xylem tissue?
It transports water and minerals FROM THE ROOT TO THE LEAVES, up the transpiration stream.
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T10- What is the role of the phloem tissue?
It transports sugars and amino acids FROM THE LEAVES WHERE THEY'RE MADE, to other parts of the plant. Know as translocation.
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T10- How do root hairs take in water?
There are cells on plant roots which grow into 'hair' like structures, and each branch of the root is covered in millions of these structures. This gives the root aa bigger surface area. Higher water potential in the soil, so water diffuses IN.
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T10- Define transpiration
It is loss of water from a leaf through evaporation or diffusion from the stomata.
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T10- What naturally happens due to transpiration?
There is an uptake of water through the xylem in the transpiration stream.
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T10- How can light affect the rate of transpiration?
When there is light, the stomata remain open to allow carbon dioxide to diffuse in, but more water is lost this way through diffusion out of the stomata..
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T10- How can temperature affect the rate of transpiration?
Heat gives the water particles more kinetic energy to diffuse faster.
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T10- How can wind speed/ humidity affect the rate of transpiration?
When there is a higher wind speed, the air outside the leaf is less concentrated with water, so water vapour inside the leaf diffuses out. When humid, the opposite happens.
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T11- What does a potometer measure?
The rate of water uptake by a plant.
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T11- How would you carry out an experiment with a potometer?
1) Cut the plant shoot underwater to prevent air entering the xylem, and at a slant to increase surface area for water uptake. 2) remove one end of the capillary tube from the water beaker until one bubble forms.
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T11- How would you measure the rate of transpiration from this experiment?
Mark the starting position of the bubble and mark on the finishing position of the bubble after a set time period. KEEP OTHER FACTORS CONSTANT.
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T11- How could you adapt this experiment?
You could vary light by using a lamp, temperature, humidity and wind speed by using a fan or spraying water into a closed system.
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T12- Define respiration
It is the process of releasing energy from glucose, happening in living cells.
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T12- What is the chemical equation for aerobic respiration?
C6H12O6 + 6O2 ---> 6CO2 + 6H2O
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T12- What is the chemical equation for anaerobic respiration in humans?
Glucose ---> lactic acid
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T12- What is the chemical equation for anaerobic respiration in plants?
Glucose ----> ethanol + carbon dioxide
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T12- What indicator can be used to demonstrate respiration, and what colour will it turn?
Hydrogen carbonate indicator will be used, and it will turn yellow if there is an increase of carbon dioxide (due to respiration.)
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T12- What would be an experiment to investigate the evolution of carbon dioxide from respiring seeds?
soak beans in water so they germinate and respire. Kill another batch of beans by boiling, so they cannot respire. Put these batches in separate test tubes on a platform with hydrogen carbonate indicator. leave for set time. respiring beans= yellow
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T12- What would be an experiment to investigate the evolution of heat from respiring seeds?
Place both killed and germinating beans in separate vacuum flasks with a thermometer. Leave for time and record the increase in temperature. The respiring beans will show a rise in heat due to respiration (heat.)
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T13- What is the net exchange of gas in photosynthesis?
Photosynthesis- more carbon dioxide diffuses in to be used in photosynthesis as there is a lower concentration inside the leaf.
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T13- What is the net exchange of gas in respiration?
Respiration- Uses some of the oxygen produced from photosynthesis, but due to the higher concentration of oxygen in the leaf, the oxygen diffuses out.
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T13- What is the difference in net gas exchange in the day/night?
day- both photosynthesis and respiration so O2 diffuses out. night- no light to photosynthesise so only CO2, a product of respiration, diffuses out.
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T13- What are the adaptations of a leaf for gas exchange?
1) Leaves are broad and thin so there is a larger surface area for diffusion of gases. 2) There are air spaces within the leaf which increase the surface area of the cells for gas exchange. 3) Stomata/holes allow water vapour/gas diffusion.
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T13- How can a leaf reduce water loss?
It will close its stomata (guard cells) when dark and dry so that water vapour cannot diffuse from the stomata.
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T13- How does hydrogen carbonate indicator work?
It detects increase in CO2 (turns yellow,) or a decrease in CO2 ( turns purple.)
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T13- How can you use this to show the differences in respiration and photosynthesis?
control tube with only indicator. 3 test tubes:3 different coverings. foil tube cannot photosythesise, only respire and will produce CO2,indicator=yellow. gauze, both processes= little colour change. no cover, takes in CO2, gives out more O2= purpl
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Other cards in this set

Card 2

Front

T9- Why do plants need nitrates?

Back

they contain nitrogen which is essential to make maino acids and therefore proteins. They need it to grow and without it, the plant will be stunted with yellow leaves.

Card 3

Front

T9- Why do plants need Phosphates?

Back

Preview of the front of card 3

Card 4

Front

T9- Why do plants need potassium?

Back

Preview of the front of card 4

Card 5

Front

T9- describe how magnesium is needed.

Back

Preview of the front of card 5
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