gas exchange and transport in plan

gas exchange

when organisms take in gases for body and release waste gases

example of gas exchange

taking in O2 and releasing CO2

photosynthesis

when light energy gets converted to chemical energy thats stored in sugars

stomata

small openings in pores of leaves that provides a passage for diffusion of gasses through waxy cuticle

guard cells

• 2 cells on left/right of stomata

• control if stomata is open or closed

if guard cells are turgid

stomata is open

if guard cells are flaccid

stomata is closed

lenticles

• pores in bark

• dont open/ close

cohesion

attraction between 2 molecules of same substance

adhesion

attraction between 2 molecules of different substances

source

• organ where photosynthesis occurs

  • stored starch breaks down here

• high concentration of sugar

sink

• organ that consumes/ stores sugar

• low concentration of sugar

where does sugar travel to

from source to sink (high concentration to low)

potassium opening stomata

• light triggers active transport of stomata into guard cells

• potassium accumulates and guard cells become hypertonic

• water enters by osmosis

• stomata opens after guard cells r turgid

potassium closing stomata

• potassium diffuses out of guard cells

• cells become hypotonic

• water leaves by osmosis

• cells become flaccid and stomata closes

transpiration cohesion method

1. transpiration:

• water evaporates and causes tension that pulls water up

2. cohesion:

• water molecules stick together via hydrogen bonds

3. adhesion:

• water adheres to walls of xylem

4. water pulled from soil

• as water leaves the leaf, tension pulls more water upward

is there ATP required in tension cohesion method

No, ATP required

Only evaporation needed

capillary action

helps water move up narrow tubes using cohesion and adhesion

Phloem transport method

• sugar goes from source to sink using active transport

• water goes to sieve tubes using osmosis

• pressure increases

• pressure pushes sugar towards sink using passive transport

• water goes back to xylem by osmosis