Gas exchange/ breathing

Question 1

by which process does gas exchange occur

Answer 1

diffusion

Question 2

who do single celled organisms respire

Answer 2

through exchange of gases by diffusion through the cell membrane

Question 3

how to fish respire

Answer 3

gills are gas exchange organs

Question 4

how to increase effieciency of gas exchange

Answer 4

larger SA- increase rate of transport

Short diffusion distance

Question 5

how does gash exchange occur in plants

Answer 5

oxygen diffuses down conc. gradient from a high to low conc. (outside to inside leaf)

Question 6

3 key gases during gas exchange

Answer 6

carbon dioxide
oxygen
water vapour

Question 7

pathway of CO2 in plants

Answer 7

atomosphere
air spaces around spongy mesophyll
leaf mesophyll cells
cholroplast

Question 8

adaptation of whole leaf for gas exchange

Answer 8

thin (short diffusion)
flat (large SA:V)
many stomata (maintain gradient)
air spaces

Question 9

what is a stomata

Answer 9

spaces found between 2 guard cells on the lower epidermis of the leaf

Question 10

what are guard cells responsible for

Answer 10

opening and closing stomatal pore which controls gas exchange and water loss

Question 11

when do stomata open

Answer 11

when water moved into cells causing them to become turgid

Question 12

how do guard cells being turgid allow gas exchange

Answer 12

allows gases to diffuse in and out through stomatal pore

Question 13

rate of photsynthesis and respiration during the day

Answer 13

plants do oth but rate of photosynthesis is higher.
- net diffusion of co2 into the plant and net diffusion of oxygen out of plant

Question 14

rate of photsynthesis and respiration during the night

Answer 14

plants only respire
- there is net movement of oxygen into plant and net diffusion of CO2 out of plant

Question 15

rate of photsynthesis and respiration at low light intensities

Answer 15

equal so there is no net movement of oxygen or carbon dioxide in either direction

Question 16

what is the gas exchange surface in humans

Answer 16

lungs

Question 17

adaptations of lungs

Answer 17

large SA:V
Thin walls
good ventillation
good blood supply

Question 18

ribs

Answer 18

bone structure that protects internal organs such as lungs

Question 19

intercoastal muscle

Answer 19

muscles between ribs which control their movement causing inhalation and exhalatoin

Question 20

diaphragm

Answer 20

sheet of connective tissue and muscle at bottom of thorax
- helps change the vol. of thorax to allow inhalation and exhalation

Question 21

trachea

Answer 21

windpipe that connects the mouth and nose to lungs

Question 22

larynx

Answer 22

aka voicebox
air passes across here to make sound

Question 23

bronchi

Answer 23

large tubes branching off the trachea with one bronchus for each lungs

Question 24

bronchioles

Answer 24

bronchi split to form smaller tubes called bronchioles in lungs connected to alveoli

Question 25

alveoli

Answer 25

tiny air sacs where gas exchange takes place

Question 26

pleural cavity

Answer 26

fluid-filled space between the pleural membranes wihch reduces friction and allows the lungs to move freely

Question 27

what are the passages down to lungs lined with

Answer 27

ciliated epithelial cells

Question 28

what are cilia cells

Answer 28

tiny hairs on end of them that beat and push mucus up the passages towards the nose and throat

Question 29

goblet cells

Answer 29

mucus made by special mucus producing cells

Question 30

what does mucus do

Answer 30

traps particles, pathogens and prevents them from getting into the lungs

Question 31

external intercoastal muscles

Answer 31

pull the rib cage up

Question 32

internal intercoastal muscles

Answer 32

pull the ribcage down

Question 33

diaphragm

Answer 33

thing sheet of muscle that separates the chest cavity from the abdomen

Question 34

during inhalation

Answer 34

- diaphragm contracts and flattens - external intercoastal muscles contra - pulls ribs up and out - this increases vol of the chest cavity - leads to decrease in air pressure inside lungs - air drawn in

Question 35

during exhalation

Answer 35

- The diaphragm relaxes it moves upwards back into its domed shape The external set of intercostal muscles relax so the ribs drop down and in This decreases the volume of the chest cavity (thorax) Leading to an increase in air pressure inside the lungs relative to outside the body Air is forced out

Question 36

adaptations of alveoli for gas exchange

Answer 36

- theyre thin - single layer cells - large SA:V - Ventiliation - good blood supply - layer of moisture

Question 37

what does smoking cause

Answer 37

chronic obstructive lung disease coronary heart disease lung cancer

Question 38

tar

Answer 38

carcinogen that causes cancer

Question 39

nicotine

Answer 39

addictive substance which narrows blood vessels

Question 40

carbon monoxide

Answer 40

reduces oxygen carrying capacity of blood

Question 41

nicotine bad side effects

Answer 41

increases heart rate leads to heart attack

Question 42

how does tar cause chronic bronchitis

Answer 42

stimulates goblet cells and mucus glands to enlarge producing mucus. It destroys cilia and mucus build up blocking smallest bronchioles

Question 43

Emphysema

Answer 43

- caused by frequent infection - phagocytes break down elastic fibres in alveoli causing them to be less elastic - reduces SA