lec 9 gas exchange

Question 1

why do humans require lungs whereas a bacterium doesn’t?

Answer 1

bacteria+protists diffuse gasses thru plasma membrane, humans do not have enough surface area exposed to do this

Question 2

the type of gas exchange system within in organism depends on…?

Answer 2

the surface area of an organism

Question 3

lungs are part of an internal system that provides us with..?

Answer 3

gas exchange surfaces

Question 4

what is the path of airflow into the lungs?

Answer 4

-breathe air thru mouth+nose

-air enters trachea

-trachea branches into smaller tubes that form lungs

-tubes end at air spaces called alveoli

Question 5

the sites of gas exchange in the lungs are called..?

Answer 5

alveoli

Question 6

what occurs in the alveoli?

Answer 6

oxygen diffuses from alveoli–>capillaries

CO2 diffuses from capillaries–> alveoli

Question 7

what is important about the walls of an alveolus?

Answer 7

very thin, so gas exchange occurs at short distance

Question 8

what type of cell makes up the walls of alveoli? What is their function?

Answer 8

epithelial cells, provide gas exchange for lungs

Question 9

which component of blood picks up the oxygen during exchange?

Answer 9

red blood cells

Question 10

protein found in RBC that can bind to and release oxygen

Answer 10

hemoglobin

Question 11

explain the gas exchange system in humans (5 steps)

Answer 11

1. oxygen enters bloodstream, diffused from alveoli
2. oxygen enters RBC+binds to hemoglobin
3. oxygenated RBC travel to tissue that requires oxygen
4. hemoglobin releases oxygen into cells
5. deoxygenated RBC back to lungs

Question 12

explain how insects ‘breathe’

Answer 12

1. air pumped into trachea
2. trachea delivers oxygen to tracheoles (small branches)
3. tracheoles diffuse gasses directly to cells

Question 13

regulate gas exchange in plants by opening and closing

Answer 13

stomata

Question 14

plant leaves are made of upper and lower…?

Answer 14

epidermis

Question 15

Palisade parenchyma

Answer 15

cells found in the upper leaf, responsible for photosynthesis

Question 16

what gas is required for photosynthesis?

Answer 16

CO2

Question 17

explain gas exchange in the leaves of plants

Answer 17

1. CO2 enters stomata in lower epidermis
2. enters airspaces to diffuse to Palisade parenchyma

Question 18

take in air and act like elastic balloons

Answer 18

lungs

Question 19

lungs contract and relax via the..?

Answer 19

diaphragm

Question 20

explain airflow from trachea to alveoli

Answer 20

down the trachea–> bronchi–>smaller bronchi–>bronchioles–alveoli

Question 21

how do individuals that live at higher elevations adapt to the lower levels of oxygen?

Answer 21

more RBC are produced with more hemoglobin