Plant And Animal Responses

Front 1

Why do organisms respond to changes in the environment?

Back 1

To increase their chances of survival

Front 2

Why do organisms respond to changes in their internal environment?

Back 2

To make sure the conditions are always optimal for their metabolism

Front 3

What is a stimulus

Back 3

Any change in the internal or external environment

Front 4

What do receptors do?

Back 4

They detect stimuli.

Front 5

What do effectors do?

Back 5

They bring about a response to a stimulus.

Front 6

In what way do receptors communicate with effectors?

Back 6

Through the Central nervous system or hormonal (endocrine) system.

Front 7

Give the 2 main structural systems in the nervous system

Back 7

The Central nervous system and the peripheral nervous system.

Front 8

What is the Central nervous system made up of?

Back 8

The Brain and the Spinal chord

Front 9

What is the peripheral nervous system made up of?

Back 9

The neurones that connect the CNS to the rest of the body.

Front 10

Give the 2 main functional systems in the peripheral nervous system

Back 10

The Somatic and Autonomic nervous systems.

Front 11

Give the functions of the Somatic nervous system.

Back 11

Controls conscious activities i.e. running, playing video games

Front 12

Give the functions of the autonomic nervous system.

Back 12

Controls unconscious activities i.e. Breathing, Digestion

Front 13

Give the 2 systems in the autonomic system.

Back 13

Sympathetic and Parasympathetic

Front 14

Give the function of the sympathetic system.

Back 14

Intiates "fight or flight" response by releasing the neurotransmitter noradrenaline.

Front 15

Give the function of the parasympathetic system.

Back 15

Initiates "rest and digest" response by releasing the neurotransmitter acetylcholine.

Front 16

Name the 5 different structures in the Brain.

Back 16

Cerebrum

Cerebellum

Medulla oblongata

Hypothalamus

Pituitary gland

Front 17

Give the location and function of the cerebrum.

Back 17

Top part of the brain, Involved in :

Thinking

Hearing

Learning

Vision

Front 18

Give the location and function of the hypothalamus.

Back 18

Found below the middle part of the brain, maintains body tenperature and produces hormones that control the pituitary gland

Front 19

Give the location and function of the Medulla oblongata.

Back 19

Base of the Brain/Top of the spinal chord

Controls breathing and heart rate

Front 20

Give the location and function of the pituitary gland

Back 20

Found just below the Hypothalamus

Releases hormones to stimulate other glands i.e. adrenal glands to release their hormones.

Front 21

Give the location and function of the cerebellum

Back 21

Found just below the cerebrum

Important for muscle coordination, posture and balance

Front 22

What is a reflex action?

Back 22

A rapid, involuntary response that doesnt involve any conscious parts of the brain.

Front 23

Why do organisms have reflex actions?

Back 23

To avoid danger to the organism

Front 24

Give the typical pathway of communication linking receptors to effectors in a reflex action.

Back 24

Stimulus to recptors to sensory neurone to CNS to motor neurone to effectors to response

Front 25

Describe what happens during the fight or flight response.

Back 25

The sensory neurone sends an impulse to the hypothalamus, activating the hormonal and sympathetic system

Front 26

How does the blinking reflex protect you?

Back 26

If your body detects potential harm, you quickly and automatically close and reopen your eyelid to protect your eye.

Front 27

How does the knee jerjk reflex help to protect you?

Back 27

It works to quickly and automatically strengthen your legs if your body detects that your quadriceps are suddenly streched.

Front 28

Describe the pathway of communication in the blinking reflex.

Back 28

Stimulus to receptor to sensory neurone to CNS (relay neurone to motor neurone) to effector

Front 29

Describe the pathway of communication in the knee jerk reflex.

Back 29

Stimulus to Receptor to Sensory neurone to CNS (directly to motor neurone, no relay neurone involved) to Effector to Response.

Front 30

How does the hormonal system help coordinate the "fight or flight" response?

Back 30

The stimulated pituitary gland releases ACTH which causes the cortex of the adrenal glands to release steroidal hormones which help respond to stress.

Front 31

How does the sympathetic system help coordinate the "fight or flight" response?

Back 31

The sympathetic system triggers the release of adrenaline from the medulla of the adrenal glands, which effects can include :

Increased Heart rate - more Oxygen for respiring muscle cells

Glycogenolysis - more glucose for respiring muscle cells

Front 32

Describe how the nervous system controls heart rate.

Back 32

Baro/chemoreceptors detect changes in blood pressure/chemistry They send impulses via the autonomic nervous system to the cardiovascular system in the medulla oblongata which sends signals via the sympathetic or parasympathetic neurones to the SAN which controls heart rate

Front 33

How does the hormonal system control the heart rate?

Back 33

Pituitary glands causes the release of adrenaline from the medulla of the adrenal glands which increases heart rate and causes the heart to pump more blood.

Front 34

What is skeletal muscle made up of?

Back 34

Large bundles of multinucleate cells called muscle cells.

Front 35

Describe the sliding filament model of muscle contraction.

Back 35

Actin and Myosin filaments slide over one another to make the sacromere contract (the myosin filaments themselves dont contract)

Front 36

Explain what happens when a muscle is at rest.

Back 36

The tropomyosin is blocking the actin-myosin binding site so the actin and myosin filaments cant slide past each other.

Front 37

Explain what happens during muscle contraction.

Back 37

The action potential depolarises the sacrolemma. Depolarisation spreads from the T-tubules to the sarcoplasmic recticulum which releases Ca2+ ions that bind to the troponin causing it to change shape and pull the tropomyosin away from the actin-myosin binding site exposing it and allowing for the myosin head to bind.

Front 38

Name the bond when happens when a myosin head binds to an actin filament.

Back 38

Actin-myosin cross bridge

Front 39

Explain what causes the actin filament to move.

Back 39

The Ca2+ ions activate ATPase which breaks down ATP into ADP + Pi which provides the energy to move the actin filament.

Front 40

Explain what causes the cross bridge to break

Back 40

The ATP also provides energy for the cross bridge to break

Front 41

Explain what happens when the muscle is returning to its resting state.

Back 41

The Ca2+ unbind from the troponin causing it to change to its original shape, pulling the attached tropomyosin with it, which means the actin-myosin site is bloacked by the tropomyosin again and the myosin heads cant bind. The actin filaments slide back to their relaxed position.

Front 42

What is a nueromuscular junction?

Back 42

A synapse between a motor neurone and a muscle cell

Front 43

How do nueromuscular junctions work?

Back 43

They use the nuerotransmitter acetylcholine to bind to the nicotinic cholinergic receptors. This triggers depolarisation in the postsynaptic cell. Acetylcholinesterase (in the clefts) is used to break down acetylcholine after use

Front 44

How do plants increase their chances of survival

Back 44

By responding to stimuli in their environment.

Front 45

Explain and give examples of abiotic stimuli.

Back 45

Natural, but non living stimuli i.e. wind, insufficient sunlight or water/nutrients

Front 46

Explain what is meant by herbivory stimuli.

Back 46

Being eaten by animals including insects.

Front 47

How do plants respond to herbivory stimuli?

Back 47

Produce chemical defences i.e. alkaloids, tannins, pheramones or folding in response to touch (Mimosa pudica)

Front 48

Describe the types of tropisms that plants can exhibt.

Back 48

Phototropism - growth in response to light

Geotropism - growth in response to gravity

Front 49

Explain and give examples of how growth hormones coordinate how plants respond to changes in their environment.

Back 49

Growth hormones i.e. auxins, gibberellin. IAA move to shaded parts of roots and shoots to control growth in response to light and gravity.

Front 50

Explain what apical dominance is and why it happens.

Back 50

It is when the apical bud inhibits the growth of side shoots and lateral buds. This occurs because auxins produced by the shoot tip inhibit the development of these lateral buds.

Front 51

What do gibberellins do?

Back 51

Stimulate the stems of plants to elongate

Stimulate seed germination by triggering breakdown of starch into glucose

Front 52

What do auxins do in a plant?

Back 52

Inhibit leaf loss

Front 53

What does ethene do in a plant?

Back 53

Stimulates leaf loss

Front 54

What does abscisic acid do?

Back 54

Triggeres the closure of stomata by causing guard cells to become flaccid.

Front 55

Give 2 examples of how plant hormones are used commercially.

Back 55

Ethene used to control when fruits ripen

Auxins used as selective weedkillers and rooting hormones