Biology paper 1

homeo

type 1 diabetes treatments

Water reabsorption in the kidney is controlled by the endocrine and nervous systems. Aldosterone and ADH are hormones that act on the kidney. Aldosterone causes sodium ions to be pumped from the collecting duct cells into tissue fluid. Describe how the endocrine and nervous systems work together to increase water reabsorption from the collecting duct.

Creatine kinase (CK) is an enzyme that catalyses reactions in heart muscle. High levels of CK in the blood indicate that a person may have had a heart attack. Suggest why high levels of CK in the blood indicate that a person may have had a heart attack.

(creatine kinase is an) intracellular (enzyme)/AW  (presence in the blood indicates) damage to heart (cells / tissue / muscle)

own:if CK is in the blood and it normally functions in muscle cells, it must have leaked out due to damage.

A technique called quantitative PCR is used to check that the E. coli population is growing on the mice liver tumours rather than on healthy tissue. Suggest how the scientists could

• extract DNA from cancerous liver and (named) healthy tissue

• primers for E.coli DNA

• compare rates of DNA amplification

define transpiration stream

movement of water

from roots to leaves

The teacher suggested that plants wld wilt if the plants had been watered with a solution containing cyanide ions that inhibit ATP synthesis. Explain whether the teacher was correct.

how can the ultrastructure of chloroplasts be changed by high temperatures?

• damage to membrane surrounding chloroplast → enzymes leak out → reducing light independent stage

• damage to membranes in chloroplast/ reduced no. sites for light capture→ reduces photophosphorylation in light dependent stage

• damage to chlorophyll/ reduces pigment → reduces light dependent reaction

Describe the sequence of actions that occur once adenylyl cyclase is activated in the target liver cells.

• adenylyl cyclase catalyses synthesis of cAMP from ATP

• cAMP activates enzymes that convert glycogen to glucose

It has been observed that some of the best sprinters only take one breath at the start of the race and do not inhale again until the end of the race. Suggest how these sprinters can expend so much energy without needing to carry out aerobic respiration.

• their cells can tolerate high levels of lactate/ acidity

• have high stores of creatine phosphate (oxygen not required)

• use of stored ATP