Chapter 5 - Summary Questions Flashcards
State three ways in which pathogens are spread.
Air, direct contact, and water.
Match each disease to the correct pathogen.
A - Malaria 1 - Virus
B - Measles 2 - Fungus
C - Salmonella food poisoning 3 - Protist
D - Rose black spot 4 - Bacteria
A - 3
B - 1
C - 4
D - 2
Name the type of cell division carried out by bacteria.
Binary fission
What is a vector?
An animal that carries a pathogen (a disease - causing an organism) from one organism (human) to another.
State two features of plants that prevent them from being eaten.
Two from: poisons; thorns; hairy stems or leaves; drooping or curling when touched; mimicry.
Describe the ways in which the structure of a tree is designed to prevent pathogen entry.
The cellulose cell wall prevents microorganisms from entering the cell; the waxy cuticle on the leaf is a barrier; bark forms a protective layer; in a leaf fall, pathogens in the leaves fall of the plant.
How does your respiratory system remove the pathogens you breathe in?
Sticky mucus traps pathogens (bacteria); cilia waft mucus and the pathogen up to be swallowed.
Describe and explain the effect in plants of:
a) nitrate deficiency
b) magnesium deficiency
a) nitrate deficiency causes stunted growth because nitrate is needed for making protein and protein is needed for growth.
b) magnesium deficiency causes yellow leaves / chlorosis and the plant will not grow; magnesium is needed to make chlorophyll and chlorophyll is needed for photosynthesis, therefore the plant cannot make the food it needs to grow.
Describe how you would prepare a pure culture of bacteria from a colony on agar gel in a flask of nutrient broth before leaving it to grow.
Add nutrients to water in a sterile flask; boil the broth and stopper the flask; flame a wire loop and then cool it (dip in alcohol to cool); touch the colony with the loop; transfer the bacteria quickly to the sterile broth (briefly dip the loop in the broth) and stopper the flask.
a) What is a zone of inhibition?
b) Calculate the area of a zone of inhibition with a diameter of 4mm to 1 decimal place.
a) A clear area on an agar gel where bacteria have not grown.
b) radius = 2mm; area = πr^2
Area = 3.141 X 4; = 12.6mm
a) How do aphids damage a plant.
b) Explain the advantage of using ladybirds instead of insecticides to kill aphids.
a) Their mouthparts penetrate the pholem vessels and such the sap so plants lose nutrients and cannot grow properly.
b) The ladybird is a natural predator (of aphids) so it does not pollute the environment; an insecticide is a chemical that can pollute air, land and water and also kills other insects that are not pests.
