Mrs H bio 2 gas exchange

Question 1

what are the thin plates that make up gills called?

Answer 1

gill filaments

Question 2

what are gill filaments covered in?

Answer 2

lamellae

Question 3

how are lamellae adapted for a faster rate of diffusion?

Answer 3

lots of blood capillaries and a thin surface area

Question 4

how are gills adapted for efficient gas exchange?

Answer 4

large surface area= lamellae and gill filaments
conc gradient= good blood supply and counter current flow
small diffusion distance= lamellae are one cell thick

Question 5

explain 2 ways the structure of the fish gills is adapted for efficient gas exchange

Answer 5

many lamellae which are thin so short diffusion distance
many gill filaments covered in lamellae for increased SA

Question 6

what is counter current flow?

Answer 6

blood flow in the opposite direction to the water so a concentration gradient is maintained and it never reaches equilibrium over the whole length of the gill/capillary ensuring water with a high conc of O2 flows next to blood with low conc of 02

Question 7

how do circulation and ventilation help to maintain a concentration gradient?

Answer 7

circulation replaces blood saturated with O2
ventilation replaces water (as O2 is removed)

Question 8

name the structure through which gases enter and leave the body of an insect

Answer 8

spiracle

Question 9

how do insects reduce water loss?

Answer 9

Waterproof covering over their body surfaces. (Rigid outer skeleton covered with
Waterproof of cuticle made of Chitin)
Smaller surface area to volume ratio

Question 10

How does oxygen move through the insect?

Answer 10

1. Oxygen enters the insect through spiracles and into the trachea, spiracle closes
2. Oxygen diffuses through trachea into the tracheoles
3. Oxygen is delivered directly to muscle tissues

Question 11

Relate the insect exchange system to Fick’s law

Answer 11

High Surface area- lots of tracheoles
Short diffusion distance- between outside and muscle cells

Question 12

explain 3 ways in which an insect’s tracheal system is adapted for efficient gas exchange

Answer 12

lots of tracheole- increased SA, fluid in the end of tracheoles that moves out during exercise for faster diffusion, tracheoles have thin walls so short d.d

Question 13

How do insects get additional oxygen during flight?

Answer 13

When at rest, water builds up in tracheoles. Drying flight, insect might respire anaerobically and produce lactic acid. This peers water potential of muscle sells so water moves via osmosis into muscle cells. This draws air into the tracheoles closer to muscle cells and reduces diffusion distance for O2 when needed most

Question 14

What are the parts of a leaf in order from at the top to bottom?

Answer 14

Cuticle, upper epidermis cells, palisade mesophyll cells, spongy mesophyll cells, air space, lower epidermis cells, guard cells and stoma

Question 15

What are the adaptations of a leaf for gas exchange?

Answer 15

Flat- large SA
stomata- pores so air can move in and out of leaf
Air spaces in leaf- short distance

Question 16

Describe gas exchange of CO2 in a leaf

Answer 16

CO2- mesophyll cells photosynthesise reducing CO2 conc in cells, CO2 diffuses into air spaces into cells, this reduces CO2 conc in air spaces causing CO2 to move into air spaces from air outside through stomata

Question 17

Describe Gas exchange of O2 in the leaf

Answer 17

Mesophyll cells produce O2 through photosynthesis, O2 diffuses into air spaces from cells, increases conc of O2 in air spaces causing O2 to move from air spaces to outside via stomata

Question 18

What are xerophytic plants adaptations for reducing water loss?

Answer 18

1. reduced no. Of stomata
2. Stomata in pits
3. Hairs to trap water vapour
4. Rolled leaves
5. Leaves reduced to spines
6. Thick waxy cuticles

Question 19

why does abdominal pumping increase the efficiency of gas exchange between the tracheoles and muscle tissue of an insect?

Answer 19

more air enters quicker so a concentration gradient/ diffusion is maintained

Question 20

what is the advantage to a fish of the one-way flow of water over its gills?

Answer 20

less energy needed and a continuous flow of water or O2