AS Paper 2 mistakes Flashcards
What is meant by active transport?
transport against a concentration gradient / from low to high
concentration
energy / ATP required
Why should the stem of a pant be cut under water before being inserted into a potometer?
Prevents air entering the stem
Allowing water transport to leaves.
What order of structures would a water molecule pass through as it moves along a symplastic pathway in a root?
Cell wall, cell membrane, cytoplasm
How does a double circulatory system in mammals lead to greater hydrostatic pressure than a single circulatory system?
Blood passes through heart twice
What is oncotic pressure causes by?
In lymph
Plasma proteins
What pressure forces fluid back into capillaries?
Oncotic pressure
What is bigger, a monocyte or a lymphocyte?
A monocyte
What is the function of a neutrophil in defence?
Engulf and digest pathogens.
Why does rate of transport of sucrose increase with higher temperatures and oxygen concentrations?
Temperature affects enzyme activity.
Oxygen increases rate of transport as it’s an active process which requires respiration
Which wave on the ECG trace occurs when the pressure in the left ventricle is highest?
T
What does the P wave represent in an ECG trace?
represents the electrical depolarization of the atria
The heart muscle is described as myogenic.
(i) State what is meant by the term myogenic.
Contractions don’t involve nerve impulses.
What is a function of cholesterol in the cell membrane?
Makes the membrane more fluid
Why does an increased ethanol concentration increase the permeability of cell membranes?
Affects the phospholipid bilayer.
What can fewer erythrocytes be a cause of?
Anaemia
What is PCR?
Polymerase Chain Reaction, to amplify DNA ie make large amounts of copies using DNA polymerase. Heated to 95oC to break hydrogen bonds and separate the strands, cool to 55oC to anneal primers and heat to 75oC to allow DNA polymerase to copy the DNA strands
Explain how gills are adapted for gas exchange.
Large surface area to volume ratio to maximise diffusion.
Thin lamallae walls to shorten diffusion distance.
Countercurrent blood flow system to maintain concentration gradient.
