hormonal communication

Question 1

Describe how adrenaline binds to cardiac cells

Answer 1

.binds to glycoprotein on plasma membrane

Question 2

Studies on the effects of hCG in humans have revealed the following information:
*Many different tissues are affected by hCG.
*Susceptible cells have glycoprotein receptors on their cell surface.
*These receptors are complementary to the shape of hCG molecules.
i. What can be concluded from this information?

Answer 2

.hCG is a peptide hormone
.binds to cell surface receptor
.hCG use cAMP as second messenger

Question 3

Which molecule does oestrogen interact with when it changes cell activity?

Answer 3

DNA

Question 4

Suggest how a hydatidiform mole could increase hCG above normal levels

Answer 4

.cells produce more hCG than normal
.due to regulation of genes

Question 5

function of adrenaline

Answer 5

.increases heart rate, blood glucose conc, glycogenolysis rate, blood pressure, air flow to alveoli, breathing rate

Question 6

function of noradrenaline

Answer 6

.increases heart rate
.increases blood pressure
.widen pupils

Question 7

function of cortisol

Answer 7

regulation of metabolism

Question 8

Name the cells that secrete insulin

Answer 8

beta cells

Question 9

Explain why it was necessary to increase the concentration of glucose surrounding the cells before they
measured insulin secretion.

Answer 9

.gluc conc causes release of insulin
.change in insulin secretion is high enough to be measured

Question 10

Explain how blocking calcium channels could inhibit insulin secretion

Answer 10

Ca2+ ions dont enter

Question 11

Name the type of differentiated cell that scientists would produce from stem cells in order to treat
diabetes mellitus.

Answer 11

b cells

Question 12

Which type of diabetes mellitus is most likely to be improved by stem cell therapy?

Answer 12

type 1 as there is a shortage of beta cells

Question 13

Evaluate the treatments for type 1 diabetes that have been used in the past as well as current and potential
future treatments.

Answer 13

pros of human insulin-
.high purity
.less risk of allergic reaction
.lower production cost
cons-
.side effects like hard lumps
.people are persuaded to change from insulin regime

Question 14

At birth, the production of another hormone, oxytocin, increases. Oxytocin causes rapid contractions of the
uterus. These contractions cause more oxytocin to be released.
What term is used to describe this kind of interaction?

Answer 14

positive feedback

Question 15

The pancreas and the adrenal glands are both examples of …………………………………………
glands. Adrenaline is a ………………………………………… that is secreted by the adrenal
glands. These glands also secrete steroids such as corticosteroids from cells in the
………………………………………… region. The chemicals secreted by these glands are
transported by the blood to their ………………………………………… cells and tissues

Answer 15

endocrine
hormone
cortex
effector

Question 16

Insulin is secreted from the beta cells of the pancreas in response to increased blood glucose
concentration.

With reference to Fig. 2.1, describe the events occurring at the stages labelled 1 to 4

Answer 16

1.glucose respired to produce ATP
2.ATP closes potassium ion channels
3.calcium ion channels open and Ca ions enter
4.Ca2+ causes movement of vesicle to membrane

Question 17

After the initial release of insulin from the beta cell, insulin secretion continues even when
there is no further glucose intake.
Suggest and explain why the cell continues to secrete insulin.

Answer 17

.continues as long as glucose concentration is higher than normal
.ATP is still present

Question 18

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 18

.glucagon released by alpha cells in pancreas
.promotes conversion of glycogen into glucouse in effector cells
.promotes conversion of triglycerides to fatty acid for respiration
.negative feedback then inhibits the secreation of glucagon

Question 19

Insulin secretion is stimulated when the blood glucose concentration
………………………………………………………………………….
Glucose enters the pancreatic cell through channel proteins. The glucose
enters the …………………………………………………………………. pathway and ATP
is produced.
The increase in ATP causes ATP-controlled potassium ion channels to close
and the cell membrane becomes ………………………………………………………….
This results in the opening of voltage-gated ……………………………………………
ion channels and the concentration of this ion inside the cell increases.
The increased concentration of these ions causes the secretion of insulin from
the cell by the process of ……………………………………………………………………..

Answer 19

increases
glycoliysis
depolarised
calcium
exocytosis

Question 20

State where in a pancreatic cell insulin molecules are synthesised

Answer 20

RER

Question 21

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

Answer 21

.transported to golgi
.modified in golgi
.packaged into vesicle
.vesicle transported to plasma membrane

Question 22

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

Answer 22

endocrine-
.hormone released directly into blood
.beta cells secrete insulin
.alpha cells secrete glucagon

exocrine-
enzymes released into duct
.triggered by hormonal stimulation
.pancreatic secreactions into small intestine

Question 23

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 23

cheap
doesnt hurt the pig

Question 24

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

Answer 24

.diff tissues have diff receptors
.causing cAMP conc to increase or decrease

Question 25

Outline the hormonal and nervous mechanisms involved in the control of heart rate.

Answer 25

.adrenaline increases heart rate
.cardoivascular centre in medulla oblongata
.nervous connection to SAN controls the frequency of waves o depolarisation
.vagus - decreases heart rate
.accelerator - increases heart rate

Question 26

With reference to the food compounds in Table 4.1, explain how a person with Type 2 diabetes
could control the condition by modifying their diet

Answer 26

.low starch as it has greatest effect on blood glucose conc
.increase protein as it has no effect on blood glucose
.some sugar

Question 27

differences between glycogen and glucagon

Answer 27

glycogen-
carb
storage role
produced in liver

glucagon-
hormone
causes convertion glycogen into glucose
formed in pancreas

Question 28

The pancreas releases hormones directly into the blood and these regulate the
concentration of blood glucose. The pancreas, therefore, acts as an
………………………………………………… gland.
When the blood glucose concentration increases, insulin is released from the beta
cells in the regions of the pancreas known as the
………………………………………………………..………………………………………………………. .
A different hormone, glucagon, is released from the alpha cells of the pancreas and this
hormone causes ………………………………………………… to be broken down into glucose,
in a process known as …………………………………………………………. .

Answer 28

endocrine
islets of langerhans
glycogen
glucogenolysis

Question 29

RNA polymerase and DNA polymerase are both enzymes. RNA polymerase is involved in the
action of some control elements, whereas DNA polymerase is not.
Describe and explain the difference between the functions of these two enzymes.

Answer 29

RNA polymerase-
makes mRNA and rRNA
transcription
one strand used

DNA polymerase-
DNA replication
both strands used

Question 30

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

Answer 30

.binds to receptor
.complementary
.g protein activated
.adenyl cyclase activated
.ATP converted to cAMP
.cAMP activates proteins