Topic 2 - Organisation Flashcards
How do tumours form
Changes in genes
Causes uncontrolled cell growth and division
Name the 2 types of tumours
Benign
Malignant
Describe a benign tumour
Tumour grows
Typically stays in the membrane
Doesn’t invade other tissues
Isn’t cancerous
Describe a malignant tumour
Tumour grows Spreads to other tissues Travels via bloodstream Causes secondary tumours Cancerous
Differences between a benign and malignant tumour
Benign stays in 1 place - Malignant invades other tissues
Benign doesn’t travel via bloodstream - Malignant travels via bloodstream
Benign doesn’t cause secondary tumours - Malignant causes secondary tumours
Benign isn’t typically dangerous isn’t cancerous - Malignant is fatal and is cancerous
3 Risk factors for cancer
Smoking Obesity UV exposure Viral infection Genes inherited
Location, function and adaptations of epidermal tissue
Whole plant
Waxy cuticle prevents water loss by transpiration
Upper epidermis is transparent which allows light through
Lower epidermis has stomata which allows carbon dioxide to diffuse into the leaf
Location, function and adaptations of palisade mesophyll tissue
Where photosynthesis occurs
lots of chloroplast near the top to absorb lots of light
Location, function and adaptations of spongy mesophyll tissue
Large air spaces in the leaf
allows gases to diffuse in and out of cells
Location and function of xylem
Stem
carries water and mineral ions
supports structure
Location and function of phloem
Stem
carries ‘food’ (glucose)
supports structure
Location and function of meristem tissue
Growing tips of shoots and roots
differentiate in different cells to allow for plant growth
What do phloem and xylem tubes carry
Phloem carries ‘food’ (dissolved sugars)
Xylem tubes carry water and mineral ions
Describe the role of phloem tubes
living cells elongated
small pores in end walls to allow cell sap to flow
Transport dissolved sugars from leaves to the rest of the plant for immediate use or storage
goes in both directions
(translocation)
Describe the role of xylem tubes
Dead cells joined end to end
hole down the middle
Carry water/mineral ions from roots to stem and leaves
only goes up the plant
