Biology Ch 15

Question 1

How does irritability help organisms to survive?

Answer 1

1. Allow them to find food
2. Allow them to find mates
3. Allow them to detect danger

Question 2

Type of receptors and their use

Answer 2

1. Photoreceptors -> detect light
2. Mechanoreceptors -> detect pressure &
   sound
3. Thermoreceptors -> detect temperature
4. Chemoreceptors -> chemical in food/air

Question 3

Process of stimuli to response

Answer 3

Receptor -> Stimuli -> Coordinator -> effotors -> Response

Question 4

Structure AROUND the eyes

Answer 4

1. Eyelid, Eyebrow, Eyelash
2. Tear gland, Tear duct
   *Conjunctiva -> 眼白

Question 5

Sclera

Answer 5

1. Protect the inner structure and maintain
   the shape of the eye
2. Provide surface muscle attachment

Question 6

**Cornea

Answer 6

1. Transparent -> refract light
2. No capillaries

Question 7

Chloroid

Answer 7

1. Black -> absorb light -> prevent efraction
2. Supply nutrients and oxygen to sclera and
   retina

Question 8

**Iris

Answer 8

1. Control the size of pupil -> regulate amount of
   light enter eyes
   Different colours

Question 9

Pupil

Answer 9

1. Allow light to enter eyes

Question 10

Retina

Answer 10

1. Contain many photoreceptors
   (Cone cell or rod cell)

Question 11

Optic nerve

Answer 11

1. Transmits nerve impulse to cerebrum

Question 12

Yellow Spot and Blind Spot

Answer 12

Yellow Spot: High conc. of CONE CELL
Blind Spot: NO any photoreceptors

Question 13

*Lens

Answer 13

1. Transparent -> refract and focus light
2. Elastic and Biconvex
3. No nuclei or capillaries

Question 14

**Suspensory ligaments and ciliary body

Answer 14

1. Ligament is connected to ciliary body
2. Ciliary muscle control the tension of ligament

Question 15

**Aqueous humour and Vitreous humour

Answer 15

1. Aqueous humour provides nutrients and
   oxygen to cornea and lens
2. Vitreous humour refracts light and maintains
   shape

Question 16

*****Process of how we see

Answer 16

1. Light enters eyes and refracted
   (cornea, lens, aqueous/vitreous humour)
2. Image form on retina
3. Photoreceptors generate nerve impulse ->
   send to visual centre along optic nerve
4. Upright image formed in visual centre

Question 17

Rod Cells

Answer 17

1. More than cone cells
2. More sensitive in dim light environment
3. Responsible for BLACK and WHITE vision

Question 18

Cone cells

Answer 18

1. More sensitive in bright light environment
2. Responsible for COLOUR vision (RGB)

Question 19

Distribution of photoreceptors

Answer 19

Cone Cells: mainly focus on yellow spot
Rod Cells: everywhere in retina
NO PHOTORECEPTORS IN BLIND SPOT

Question 20

Seeing in bright light

Answer 20

1. Circular muscles contract
2. Radial muscles relax
3. Pupil constricts

Question 21

Seeing in dim light

Answer 21

1. Circular muscles relax
2. Radial muscles contract
3. Pupil dilates

Question 22

Seeing near object

Answer 22

1. Ciliary muscle contract
2. Tention of suspensory ligaments reduced
3. Lens become thicker -> refract more light

Question 23

Seeing distant object

Answer 23

1. Ciliary muscle relax
2. Temtion of suspensory ligaments increased
3. Lens become thinner -> refract less light

Question 24

Short sight

Answer 24

1. Can’t see distant thing clearly
2. Eyeball too long / lens too thick -> image form
   in front of retina
3. Wear concave lens

Question 25

Long sight

Answer 25

1. Can't see near thing clearly 2. Eyeball too short / lens too thin -> image form behind 3. Wear convex lens

Question 26

Colour blindness

Answer 26

1. Red-green colour blindness (Total colour blindness is rare) 2. Definciency or defect of cone cell 3. Can't be cure by wearing glasses

Question 27

Out ear

Answer 27

Pinna: collect sound wave Eardrum: convert sound wave to vibrations

Question 28

Middle ear

Answer 28

Ear bones: amplify and transmit vibrations Oval window: transmit vibrations to inner ear Round window: Release fluid pressure Eustachian Tube: Equalize air pressure

Question 29

Inner ear

Answer 29

Cochlea: Endolymph->many sensory hair cells Sensory hair cells vibrate -> nerve impluse -> go to auditory centre Semicircular canal: (NOT ABOUT HEARING) -> detect head movements -> maintain balance

Question 30

Process of how we hear

Answer 30

1. Sound wave direct to eardrum 2. Sound wave convert to vibrations (Eardrum) 3. Amplified and transmit vibrations (Ear bones) 4. oval window -> perilymph vibrate 5.Vribations transmit to endolymph 6. Sensory hair cells generate nerve impluse to auditory centre 7. Release fluid pressure (round window)

Question 31

Phototropism of plants

Answer 31

1. Shoot grow toward light (positive phototropism) 2. Root grow away form light (negative phototropism)

Question 32

Conclusion of 4 experiments

Answer 32

1. Tip is necessary for growth and detect light 2. Auxins are chemical in nature -> can transmit to lower part 3. Auxins will move to shaded side 4. Higher conc. of auxins will grow more rapidly 5. Light will cause uneven distribution of auxins

Question 33

Where can i find auxins

Answer 33

Tips -> Region of elongation

Question 34

Effect on auxin conc. on growth of shoot and root

Answer 34

High conc. -> PROMOTE shoot growth but INHIBIT root growth Low conc. -> PROMOTE root growth

Question 35

If light comes from every direction, what happen to the plant?

Answer 35

Auxins distrubute evenly -> grow vertically

Question 36

If light comes from one direction, what happen?

Answer 36

Auxins move to shaded side -> high conc. pf auxin promote shoot growth and inhibit root growth