Chapter 2: Organisms in the environment Flashcards
What is the word equation for photosynthesis?
Carbon Dioxide + Water —–> Glucose + Oxygen
What substance does photosynthesis take place in?
Chlorophyll
Where is chlorophyll found?
In Chloroplasts.
If not all of the glucose created in photosynthesis is used immediately, what is the glucose stored as?
Insoluble Starch
What does Iodine solution Test for?
Starch
How do you test for starch?
Using Iodine Solution (Yellow = no starch, Blue = starch)
How is a leaf adapted to its task of photosynthesis? (4 main reasons)
- They have a large surface area
- They contain Chloroplasts w/ chlorophyll to absorb light energy
- They have stomata and air spaces to allow Carbon Dioxide to reach cells inside the leaf
- They have veins which bring water to the cells
What is the top layer of cells on a leaf called?
The upper epidermis
What is the function of the upper epidermis?
To excrete a ‘waxy cuticle’ which protects the leaf from water or other unwanted particles entering it.
What is the second layer of a leaf called? What is it’s function?
The palisade layer, its where most photosynthesis takes place.
How is the ‘palisade layer’ adapted to do it’s job?
- Lots of chloroplasts to absorb light energy
- Close to the surface to maximize light reaching it
- Compact arrangement to maximize area that can photosynthesise
What is the third layer of cells in a leaf called? What is it’s function?
The spongy layer. It allows carbon dioxide to diffuse into the cells to aid photosynthesis.
What is the last layer of a leaf called?
The lower epidermis
Name the limiting factors of Photosynthesis.
Light Levels, Temperature and Carbon dioxide concentration.
From 0 to a higher value, levels of light and carbon dioxide will cause the rate of photosynthesis to increase. However, past a certain point the increase will level out. Why?
The rate of Light/Carbon dioxide uptake is greater than the rate at which the plant can use it up.
From 0 to a higher value, increasing Temperature will cause the rate of photosynthesis to increase. However, past a certain point the rate will suddenly fall. Why?
The enzymes that control photosynthesis are denatured.
How do plants make amino acids?
By combining mineral ions (e.g. nitrate ions) with glucose
How is glucose used in a plant?
It is combined with oxygen to produce energy which goes into chemical reactions inside cells.
Why do we prefer to grow crops/fruit in greenhouses?
- The environment can be controlled much more accurately
2. Less risk of attack from pests
Systems that strive to take complete control over the limiting factors of plants/photosynthesis are grouped as…
Hydroponics
What are the limiting factors for organisms?
- Temperature
- Nutrient Levels
- Amount of light
- Availability of water
- Availability of Oxygen or Carbon dioxide
What tool could you use to measure the distribution of plant life or small animal life?
A Quadrat
What must you never ever Ever EVER do with a Quadrat?
Throw it! D:
How do you choose the sample sites when using a quadrat?
You must choose them randomly.
A good way to do this is by dividing the area up into a grid and using a random number generator to generate co-ordinates.
When you had finished using a quadrat to sample an area, what would you do to your results?
Find the mean number of organisms per sample.
What is sampling along a transect?
Following a set path between two points (usually a line) and measuring the amount of an organism at regular intervals using a quadrat.
When you sample along a transect, what are you measuring?
The change in the distribution of an organism along a path. This can be linked to other factors that also change along the path, such as light and ph levels or temperature.
What is a reproducible method?
A reproducible method is one which can can be repeated by others and found to produce similar results each time.
What is valid data?
Data that answers the question that the investigation poses.
