Midterm 2

Question 1

Describe parenchyma cells of plants

*draw

Answer 1

-called ground tissue
-thin, flexible walls(primary/ no lignin)
-2 main functions:
>storage
>food production
-living cells at maturity
-contains large central vacuole
-photosynthetic and may contain many chloroplasts
-has air spaces between adjacent parenchyma cells
-make up spongy and palisade mesophyll
-in stems/roots/leaves
-least specialized

Question 2

Describe collenchyma cells

*draw

Answer 2

• long, varying thickened cell walls (primary, no lignin)
• alive at maturity
• near stem surfaces and along the leaf veins
• extremely flexible
• structural support for non woody plant organs(no lignin)
• no metabolic function(don’t perform ps or cr)
• grouped in strands or columns
• no lignin so won’t restrain growth

Question 3

Describe sclerenchyma cells

*draw

Answer 3

-dead at maturity
-thick secondary cell walls-has lignin
-often in xylem tissue
-provides structural support
-hard-woody cells
-don’t photosynthesize
-found in parts of plant that are no longer growing so it won’t restrain growth (middle, not in root or shoot tips)
-two forms:
fibres
Ex. Wood or bark
or
sclereids
Ex. Grits in pears
-in fruits or seeds