Topic 3 - Wood Wide Web Flashcards
Explain the difference between an autotroph and heterotroph, stating how they gain nutrients.
Autotrophs feed themselves to meet their energy requirements; rely on chlorophyll-based photosynthesis
Heterotrophs rely on other organisms to feed them; they ingest complex organic molecules that have been synthesised by another organism
What is a simple sugar? Give an example.
A carbohydrate molecule with between 3 - 7 carbon atoms, that free floats in a cell.
Example - fructose.
What is a disaccharide? Give an example.
A pair of simple sugars that have joined to form a larger molecule.
Example: sucrose, lactose, maltose.
What is the difference between an oligosaccharide and a polysaccharide? Give an example.
An oligosaccharide is a short chain of carbohydrate sugars, for example fructans.
Polysaccharides are more common and form longer chains for sugars for storing carbohydrates.
Example: starch (plants) and glycogen (animals).
What is TAG?
TAG (Triacylglycerol) is a lipid. It is a chain of three fatty acids linked by ester links to a glycerol molecule.
Name three approaches for gaining products from other organisms, giving examples of types of organism in each category.
Saprotroph - eats of already dead material, eg. detritivore, scavenger
Necrotroph - kills living material to feed, eg. carnivore (lion)
Biotroph - feeds off living material, eg parasite (tapeworm)
How do animals (eg. carnivores) prevent excess nitrogen amine groups becoming toxic, after eating lots of protein?
Amine groups combine with CO2 to create urea, which is neutral in pH and can be excreted into the environment directly or after being extract from blood by the kidneys
Give three reasons why organisms tend to excrete rather than store excess nutrients.
Excess weight can mean they lose a competitive advantage.
Many are toxic in higher levels, eg. nitrogen can raise pH levels and interfere with metabolism.
Chlorides interfere with osmosis, and high levels of solutes affect movement of proteins across cell membranes.
What is Liebig’s law of the minimum?
It is that the essential nutrient that is in shortest supply with limit growth.
What is altruism?
Where an organism helps another without any direct benefit to itself.
What is co-evolution?
It is when two different species evolve in parallel, because the relationship benefits them both (mutualism).
What is amensalism?
A species does not benefit directly from its interaction with another species, but the interaction has a clear disadvantage for the other species.
(0,-)
What interaction is meant by (+,0)
Commensalism. This is where a species shares space with another and is not harmed by it.
Which [three] groups of organisms are unikonts?
Animals, fungi and slime moulds.
The cells have just one flagellum.
What is the feature of bikonts and which three organism groups are they?
Cells have two flagella.
Flowering plants, mosses and algae.
What is saprotrophy?
It’s the ability to use dead organic matter as a food source.
How is necrotrophy different from saprotrophy?
In nectrotrophy, a fungi first kills live cells and then ingests them, whereas in saprotrophy the fungi consumes organic matter that is already dead.
What are the THREE processes by which a fungus can extract nutrients - give a brief explanation.
- Saprotrophy – dead organic matter
- Nectrotrophy – kill live cells, then consume
- Biotrophy – extract from living tissues
What are the two tactics that plants have to defend against fungi?
Hypersensitive response - release hydrogen peroxide to isolate the infection by killing the fungi and cells its on.
Produce anti-fungal toxins that interfere with the fungi’s metabolism and/or degrate fungal cell walls.
What is the name of the enzyme at the heart of the C3 pathway?
Rubisco
What causes photoinhibition and what damage can it do?
Too much light means dark reactions can’t occur fast enough, leading to an excess of ATP.
This can reduce the efficiency of photosynthesis by damaging chlorophyll molecules and their membranes.
What is a plastid?
It is a cell organelle that has a specialised metabolic process. They are only found in eukaryotes.
What are the main divisions of mycorrhiza based on?
Does the fungi penetrate the plants root or not?
If yes = endomycorrhiza.
If no = ectomycorrhiza.
In addition to autotrophs, that gain their energy from the sun, what are the THREE other types of plant and how to they gain their energy?
Hemi-parasitic - take some nutrients from other plants but still photosynthesises (autotroph + biotroph)
Parasitic - take nutrients are carbs from other plants
Carniverous - consume other organisms (autotroph + necrotroph)
