YEAR 10 Plant Structure And Function Flashcards
Osmosis definition
Movement of water from an area of high water concentration to low water concentration
Through a semi-permeable barrier
Word equation for photosynthesis
Carbon dioxide + Water -> Glucose + Oxygen
Symbol equation for photosynthesis
6CO2 + 6H2O -> C6H12O6 + 6O2
What is the ‘skin’ of a leaf called
Epidermis
What happens to excess glucose in plants
Converted into starch which can be broken down back into glucose
What colour does iodine go in starch
Blue/Black
(From orange)
What are the 3 limiting factors for photosynthesis
Light intensity
Availability of carbon dioxide
Temperature
Which type of cells in leaves would have the most chlorophyll
Palisade mesophyll
Why does a higher light intensity cause solutions with plants to become less acidic
Allows for faster rate of photosynthesis
More acidic CO2 absorbed by plant
What is the purpose of the Xylem
To transport water and minerals UP
From roots to stem and leaves
Does the xylem need energy for transport
No
What is the purpose of the phloem
Transports sucrose from leaves to the rest of the plant
Does the phloem need energy for transport
Yes
What is Transpiration in plants
Movement and evaporation of water away from the inside of the plant
What is translocation in plants
Dissolved sugars are moved from the leaves (SOURCES) through the Phloem to the places where it is needed (SINKS)
What is the role of stomata
To let in CO2
What allows guard cells to OPEN
They absorb water and become turgid
Why do guard cells close on hot days
to prevent water loss by evaporation
Why do guard cells close at night
No light -> No need for CO2 as cannot photosynthesise
What is a SOURCE in a plant
A photosynthesising part
What is a SINK in a plant
A part where sugars are needed
What is gravitropism
Growth responses related to gravity
How does gravitropism affect Roots
Positive gravitropism
Following pull of gravity
How does gravitropism affect Shoots
Negative gravitropism
Against the pull of gravity
What are auxins in plants
Hormone made in root and shoot tips
Cause tips to absorb more water to grow more quickly
How do auxins cause Gravitropism
Auxins accumulate on the lower sides of shoot to cause shoot to grow up
How do auxins cause plants to move towards light
Auxins accumulate on dark side of shoot
Cause shoot to bend towards light
Why does moving air increase the rate of transpiration
Removes water vapour around leaf
More water moves out of leaf by osmosis (steeper gradient)
