5.1.1-communication and homeostasis

Question 1

what is a receptor
5.1.1.(a)

Answer 1

detect stimulus (internal or external) and signal to effector

Question 2

what is an effector
5.1.1(a)

Answer 2

receives signal from receptor and carries out a response

Question 3

what is a communication system
5.1.1(a)

Answer 3

transmits information between receptor and effector that may be far apart

Question 4

what are the 2 major communication systems and what do they do
5.1.1(a)

Answer 4

-nervous system (electrical impulses)
-endocrine system (hormones)

Question 5

what communication system do plants rely on
5.1.1(a)

Answer 5

mainly hormonal

Question 6

what is cell signalling
5.1.1(b)

Answer 6

-idea of specificity
-cell signalling involves molecules that have a specific shape which is complementary to the cell surface receptor
–plants can also respond to soluble materials

Question 7

what is homeostasis
5.1.1(c)

Answer 7

state of stable internal conditions are kept within the set point

Question 8

how do organisms respond to changes in the internal environment
5.1.1(c)

Answer 8

stimulus—>receptor—->communication system——->effector——–>response

Question 9

what is the difference between positive and negative feedback
5.1.1(c)

Answer 9

positive-exaggerates change
negative-counteracts change

Question 10

explain the negative feedback loop
5.1.1(c)

Answer 10

the receptors detect the change and signal to the effector to carry out the response and bring the condition back to the optimum

Question 11

explain the positive feedback loop
5.1.1(c)

Answer 11

the receptors detect the change and signal to the effector to carry out the response to amplify the change

Question 12

explain hypothermia
5.1.1(c)

Answer 12

positive feedback, is when an initial (biological) change is, increased further / exaggerated / AW ✓

lower temperature reduces kinetic energy (of molecules) ✓

enzyme activity, slowed / reduced ✓

respiration rate / metabolism, slowed / reduced ✓

less (metabolic / internal) heat generated ✓

(so that body) temperature drops further

Question 13

what is thermoregulation
5.1.1(d)

Answer 13

process by which organisms maintain a constant core body temperature (within a range)

Question 14

what is the difference between ectotherms and endotherms
5.1.1(d)

Answer 14

ectotherms-behavioural responses
endotherms-behavioural and physiological responses-uses heat generated from metabolic processes.

Question 15

what are some examples of behavioural responses to warm up
5.1.1(d)

Answer 15

-bask in sun
-sit on hot ground
-move more (respiration releases heat)
(opposite for cool down)

Question 16

what are some physiological responses to cool down
5.1.1(d)

Answer 16

-increase sweat production
-erector pili muscles relax
-vasodilation
-decrease metabolic rate
-shiver

Question 17

what are the two types of thermoreceptors in the body
5.1.1(d)

Answer 17

-peripheral temperature receptors
-hypothalamus receptors

Question 18

what do peripheral temperature receptors do
5.1.1(d)

Answer 18

monitor temperature of environment

Question 19

what do hypothalamus receptors do
5.1.1(d)

Answer 19

monitor temperature of blood

Question 20

what is the comparison between SA to V ratio and heat loss
5.1.1(d)

Answer 20

large SA to V ratio will have a high heat loss
small SA to V ratio will have low heat loss so can maintain core body temperature

Question 21

what is one advantage and disadvantage that ectotherms have compared to endotherms

Answer 21

ectotherms-more energy can be used for growth and reproduction
ectotherms may be susceptible to freezing and can be at risk of predators when body temperature is low.