lqc 2d exam qs

Question 1

Give two reasons why a sieve tube element does not require rough endoplasmic reticulum and ribosomes.

Answer 1

• there will be no transcription
• no proteins will be synthesised to be processed in endoplasmic reticulum

Question 2

Describe the differences between the structure of xylem and that of phloem.

Answer 2

• xylem cell wall contains cellulose and lignin whilst phloem cell wall contain only cellulose
  -xylem is hollow but phloem has cell contents
• xylem has pits but phloem doesnt