Chapter 5 - Coordination and Regulation: Endocrine Systems

Question 1

stimulus response model definition

Answer 1

a change in the environment is received by a receptor and the organism interprets that change and responds in a way to protect the organism (restore stability)

Question 2

steps of stimulus response model

Answer 2

SRCER
stimulus: change
receptor: detect change
communication systems: signalling molecules
effector: initiates response
response: change

Question 3

signalling molecule

Answer 3

molecules that carry signals or messages from one cell to another
enable cells to communicate

Question 4

principles of cell communication

Answer 4

PDTRC
production of signalling molecule
detection of the signal by a receptor protein
transduction of this signal through the cell
response of the cell
control of regulation

Question 5

hormone

Answer 5

signalling molecule that brings about a response in a target cell
do not last indefinitely

Question 6

some hormones may:

Answer 6

act on the same cells that produce them
be secreted into the extracellular fluid and act on cells close by
enter the blood stream and act on distant cells

Question 7

how does a hormone stimulate a repsonse

Answer 7

must find bind to receptor

Question 8

receptor hormone complex

Answer 8

complementary hormone and receptor bonded

Question 9

why don’t hormones last indefinitely

Answer 9

delivered signal to target cells
desired effect has occurred
degraded by cell enzymes
excreted (urine/faeces)

Question 10

two hormone types

Answer 10

lipid based (steroid) hormones
protein based hormones

Question 11

lipid based (steroid) hormones

Answer 11

lipophilic
easily pass through membranes
intracellular receptors
e.g. testosterone, oestrogen

Question 12

protein based hormones

Answer 12

hydrophilic
can’t pass through membranes
extracellular receptors: on surface of plasma membrane
e.g. insulin, glucagon

Question 13

signal transduction

Answer 13

cascade of events linking an external signal to a specific cellular response
information passed from receptor to effect

Question 14

steps of signal transduction

Answer 14

reception: info received by cell’s receptor
transduction: info from receptors passed onto effectors
induction / response: various cellular responses initiated

Question 15

example of responses to signal transduction

Answer 15

activation of genetic material -> production of proteins

production of another signalling molecule

Question 16

pheromones

Answer 16

chemical signalling molecules secreted by animals that evoke a response in another animal of the same species
species specific

Question 17

why do plants secrete hormones

Answer 17

help coordinate plant development in response to the environment

Question 18

apoptosis

Answer 18

regulate or programmed cell death

Question 19

instances when apoptosis is needed

Answer 19

menstruation: shedding of endometrium
metamorphosis: tadpole to frog
formation of fingers and toes in foetus
cancer cells
viruses

Question 20

where are hormones produced

Answer 20

endocrine system

Question 21

where are neurotransmitters produced

Answer 21

axon terminal

Question 22

where are pheromones produced

Answer 22

animals

Question 23

where are plant growth regulators produced

Answer 23

plants

Question 24

where do hormones transport

Answer 24

travel in extracellular fluid or bloodstream

Question 25

where do neurotransmitters transport

Answer 25

across synaptic gaps

Question 26

where do pheromones transport

Answer 26

secreted into external environment

Question 27

where do plant growth regulators transport

Answer 27

carried in plant vascular tissue (xylem and phloem)

Question 28

what do hormones target

Answer 28

specific cells respond to each hormone

Question 29

what do neurotransmitters target

Answer 29

dendrites of other neurons to continue impulse

Question 30

what do pheromones target

Answer 30

other members of the same species

Question 31

what do plant growth regulators target

Answer 31

plant tissues to stimulate activities such as growth, flowering and fruiting

Question 32

Homeostasis

Answer 32

The main range of a relatively stable internal environment, within narrow limits, despite changes in the external environment

Question 33

Auxin

Answer 33

Control enlargement and elongation of plant cells

Question 34

Ethylene

Answer 34

Causes leaves to fall off

Ripens fruits

Question 35

Gibberellins

Answer 35

Promote plant growth

Stimulates cell elongation and reproduction

Question 36

Tropism

Answer 36

The growth of a plant in response to a stimulus such as light or water

Question 37

Phototropism

Answer 37

When a plant moves in response to light

Positive if toward light

Question 38

Why do plants bend toward light

Answer 38

Auxin moves away from light
Promotes growth on one side more
Bends towards light

Question 39

Geotropism

Answer 39

Response if shoot or root to gravity

Question 40

Cytokinins

Answer 40

Promote cell reproduction in plants

Question 41

Abscission

Answer 41

Falling of cells or fruit

Question 42

Glucagon

Answer 42

Hormone produced by alpha cells of the pancreas that acts on the liver cells resulting in an increase release of glucose from the liver cells into the bloodstream

Question 43

Phloem

Answer 43

Transports sugar

Question 44

Xylem

Answer 44

Transports water and minerals