hormonal communication

Question 1

the events of insulin secretion

Answer 1

1 glucose respired or phosphorylated to produce ATP

2 ATP , blocks / closes , potassium ion channel(s) 
and potassium ions / K+  
build up (inside cell) 

3 (voltage-gated) calcium ion / Ca2+ channels open
and calcium ions / Ca2+ enter (cell by diffusion) ;

4 (more) calcium ions / Ca2+
resulting in movement of vesicles to membrane /
exocytosis

Question 2

suggest and explain why the cell continues to secrete insulin after no further glucose intake

Answer 2

1 (continues to be secreted) as long as
blood / plasma , glucose (concentration) , 
remains high / is higher than normal ; 
2 (sufficient) ATP is still present 
and so K+ 
channels remain closed ; 
3 (exocytosis) still being triggered by , 
calcium ions / Ca2+;

Question 3

Under what circumstances might this patient need to be given a glucagon injection?

Answer 3

1 if blood glucose falls ,
extremely / dangerously / too / very , low
;
2 if patient , cannot produce (enough) glucagon /
produces little glucagon ;
3 idea that glucose source cannot be taken by mouth ;

Question 4

Suggest an explanation for the patient’s high value for the fasting blood glucose test.

Answer 4

patient might have had a drink containing sugar

Question 5

Describe how glucagon is involved in the regulation of blood glucose concentration in a person who is able to regulate their blood glucose concentration correctly.

Answer 5

when blood glucose concentration decreases
1 (glucagon) released by the , alpha / , cells in ,
islets of Langerhans / pancreas ;
2 promotes / AW ,
conversion of glycogen to glucose /
glycogenolysis ,
in , liver / muscle / effector , cells ;
3 ref gluconeogenesis / described ;
4 ref conversion of triglycerides to (free) fatty acids /
lipolysis /
increased use of fatty acids in respiration ;
5 negative feedback ,
reduces / inhibits , the secretion of glucagon ;
6 glucagon , reduces / inhibits , insulin secretion
QWC
alpha, islet,
pancreas , glycogen,
glycogenolysis, effector,
gluconeogenesis, negative feedback

Question 6

Urine can be tested to detect a person’s misuse of certain drugs in body-building.State the type of drug that can be misused in this way.

Answer 6

anabolic steroids

Question 7

Name one hormone which will increase the heart rate.

Answer 7

adrenaline / epinephrine / noradrenaline / norepinephrine ;

Question 8

Name the endocrine tissue in the pancreas that is responsible for secretion of hormones.

Answer 8

islet(s) of Langerhans ;

Question 9

State where in a pancreatic cell insulin molecules are synthesised.

Answer 9

ribosome / rough endoplasmic reticulum / RER ;

Question 10

Outline the events that occur after the synthesis of an insulin molecule until it is ready to be secreted from the pancreatic cell.

Answer 10

1 transported to Golgi ;
2 modified / processed , in Golgi ; 
3 packaged into / stored in , (Golgi) vesicle(s) ; 
4 vesicles transported towards , 
plasma / cell surface , membrane ;

Question 11

Describe how negative feedback is used to control blood glucose concentration

Answer 11

1 a cells / receptors detect
change / increase / decrease
in blood glucose conc
2 if high(er) glucose conc
beta / cells (in pancreas) release insulin ;
3 (increased) uptake / absorption , of glucose by ,
liver / muscle / effector , cells
4 enters through glucose transport proteins
(in cell surface membrane) ;
5 glucose converted to glycogen / glycogenesis ;
6 increased (use of glucose in) , respiration / ATP production ;
7 if low(er) glucose (concentration) ,
alpha / (in pancreas) cells release glucagon ;
8 (increased) conversion of glycogen to glucose / glycogenolysis ;
9 (increased) conversion of other compounds
(amino acids / lipids) to glucose / gluconeogenesis ;
10 glucose leaves cells ,
by facilitated diffusion / through glucose channels ;

Question 12

Suggest why fatigue may occur in a person with Type 2 diabetes who is not taking medication.

Answer 12

1 not enough / less , glucose uptake into cells ;
2 not enough / less , glucose / substrate , for ,
respiration / ATP production ;
3 glucose not , stored as / converted to , glycogen ;

Question 13

Describe the different ways in which the pancreas acts as both an endocrine and an exocrine gland

Answer 13

endocrine
H1 hormone(s) released directly into blood ;
H2 beta / β , cells , secrete / produce / release , insulin ;
H3 alpha / α , cells , secrete / produce / release , glucagon ;
H4 islet /  and  , cells , detect / monitor ,
blood glucose concentration ;
3 max
exocrine
E1 fluid / juice / secretion / enzymes , released into duct ;
E2 (release triggered by) nervous / hormonal , stimulation ;
E3 pancreatic secretions into ,
gut / small intestine / duodenum ;
E4 alkaline / pH 8 / (sodium) hydrogen carbonate ;
E5 containing 2 named enzyme(s) ;
QWC
hormone(s), beta, alpha,
glucagon, islet(s), pancreatic,
duodenum, enzyme(s), amylase,
trypsin(ogen) / chymotrypsin(ogen)

Question 14

State two advantages of treating Type 1 diabetes by using insulin that has been produced by genetically modified bacteria rather than insulin that has been extracted from pigs.

Answer 14

1 idea of plentiful / dependable , supply ;
2 cheap ;
3 not cruel to pigs / more ethical ;
4 no religious objections / can be used by vegetarians ;
5 reliable , quality / standard ;
6 (exact match to) human insulin / no allergic reaction ;

Question 15

State an advantage of this form of treatment compared to treatment using insulin.

Answer 15

1 (has the potential to) cure / do more than manage ,
the condition ;
2 long term effect / permanent /
no need for repeated treatments ;

Question 16

Suggest what happens to polysaccharides in the liver cell

Answer 16

glycogen glucose / glycogenolysis ;
by hydrolysis ;
correct ref to
protein kinase / glycogen phosphorylase kinase
(activates glycogen phosphorylase)
or
glycogen phosphorylase
(stimulates conversion of glycogen)
or
inhibition of glycogen synthase
(preventing glucose conversion to glycogen) ;

Question 17

Suggest how the adrenaline molecule can cause different effects in different target tissues.

Answer 17

different tissues have different (types of adrenaline)
receptors ;
(causing) cAMP concentration to increase or decrease ;
second messenger (may be) different ;
cAMP / second messenger , activates ,
different / other , enzymes / enzyme reactions
(in different target cells) ;

Question 18

Comment on whether the use of steroids should be permitted in sport.

Answer 18

1. fairness / giving unfair advantage /
   does not give an ‘even playing field’ ;
2. idea of health risks / dangerous / unhealthy / fatal
   side effects ;
3. idea of distrust of ‘outstanding’ performances /
   does not reflect athlete’s natural talent /
   sport should reflect athlete’s natural talent ;
4. idea of pressure to keep up with rival competitors ;
5. idea that can train for longer (without tiring) /
   can respire longer (without tiring) /
   can recover from injury quicker /
   can build up muscle mass ;

Question 19

Explain how Type 1 diabetes is caused.

Answer 19

unable to produce (enough) insulin / do not secrete insulin /
produces ineffective insulin ;
insulin-producing cells / beta cells / islets of Langerhans,
not functioning (correctly) / damaged / destroyed / attacked ;
by (body’s own) immune system / by (body’s own) antibodies /
auto-immune disease ;
(idea of) family history / genetic / hereditary ;
(condition can be) triggered by , virus / environmental factor ;

Question 20

Describe three factors that increase a person’s risk of developing Type 2 diabetes.

Answer 20

increasing age / older / ageing / more prevalent over 40 ;
(idea of) family history / genetic / hereditary ;
(more common in) males ;
(more common in)
some ethnic groups / African / Afro-Caribbean / Asian /
Hispanic / Oceanic ;
obese / overweight / fat around abdomen ;
high / frequent, intake of ,
sugar / highly processed food / high GI food ;
lack of physical activity / sedentary lifestyle ;
high blood pressure ;
excessive alcohol intake ;

Question 21

Suggest why it is necessary to add an anticoagulant to the blood in stage 2.

Answer 21

so that clots don’t form,

while in the (dialysis) machine / during dialysis ;

Question 22

Suggest why no anticoagulant is added to the blood towards the end of a dialysis session.

Answer 22

idea of allowing blood to clot normally after treatment ;

Question 23

State the process by which molecules and ions, other than water, will move from the blood into the dialysate.

Answer 23

(simple) diffusion ;

Question 24

Suggest why the direction of flow of the blood and the dialysate

Answer 24

idea that it, maintains diffusion gradient /
 maintains concentration gradient /
 maximises diffusion gradient /
 maximises concentration gradient /
 allows maximum removal of waste /
 allows maximum rate of diffusion / AW ;

Question 25

Describe two similarities in the action of plant and animal hormones in cell signalling.

Answer 25

(hormone) binds to receptor ;
2 causing , cascade of events / enzyme reactions ;
3 may involve switching , on / off, genes ;
4 only , present / needed , in small ,
concentrations / quantities (to have an effect) ;
5 may have effect on more than one ,
location / target tissue ;
6 idea that effect may involve interaction of
more than one hormone ;

Question 26

State three differences in the ways in which plant and mammalian hormones operate.

Answer 26

1 (M) made in endocrine glands versus
(P) made in many plant tissues ;
2 (M) move in blood versus
(P) move, in xylem / in phloem / from cell to cell ;
3 (M) act on, a few / specific / target, tissues versus
(P) act on most tissues / can act in cells where produced ;
4 (M) act more rapidly ; ORA

Question 27

Describe the events that occur after adrenaline reaches the cell surface membrane that then result in changes in metabolism inside the cell cytoplasm.

Answer 27

1 adrenaline binds to receptor ;
2 complementary / specific, fit / shape ;
3 G protein activated ;
4 adenyl(ate) cyclase activated ;
5 ATP converted to cAMP ;
6 cAMP activates, proteins / enzymes ;
7 by, altering 3D structure / phosphorylation ;

Question 28

Suggest how having a number of steps in the signalling pathway enables a small number of adrenaline molecules to rapidly cause large effects.

Answer 28

idea that one / named, molecule causes, production / activation of,
many others ;
idea that this multiplying effect is repeated at, next / every / later step ;
idea of recycling / temporary binding, of cAMP ;

Question 29

pregnancy

Answer 29

detect human chorionic gonadotropin in urine of pregant women

1) stick is used with an application area that contains monoclonal antibodies for hCG bound to a coloured bead(blue). monoclonal antibodies are all identical to each other
2) when urine is applied to the application area any hCG will bind to the antibody on the beads
3) urine moves up the test strip, carying the beads with it
4) the test strip has antibodies to hCG immobilised
5) if there is hCG present the test strip turns blue because the immobilised antibody binds to any hCG attached to the blue beads, concentrating the blue beads in that area. If no hCG is present, the beads wont pass through the test area without binding to anything, and so it wont go blue