4.6 tissues and organs in plants

Question 1

leaf function

Answer 1

carries out photosynthesis

Question 2

stem function

Answer 2

supports leaves and flowers

Question 3

flower function

Answer 3

reproductive part of the plant

Question 4

root function

Answer 4

absorbs water and mineral ions and anchors plant to the ground

Question 5

name the types of leaf tissues from top to bottom

Answer 5

• waxy upper
• upper epidermal
• palisade mesophyll
• spongy mesophyll
• vascular bundle
• lower epidermis
• stomata + guard cells

Question 6

epidermal tissue function and adaptations

Answer 6

• covers surfaces and protects them
• secrete a waxy substance that waterproofs the surface of the leaf

Question 7

palisade mesophyll function and adaptations

Answer 7

• to carry out photosynthesis
• contains many chloroplasts

Question 8

spongy mesophyll function

Answer 8

• carries out some photosynthesis
• allows for the diffusion of gases

Question 9

spongy mesophyll adaptations

Answer 9

• contains some chloroplasts
• has big air spaces and a large surface area to make the diffusion of gases easier

Question 10

xylem function

Answer 10

to carry water and dissolved mineral ions from roots to leaves

Question 11

xylem adaptations

Answer 11

• cells join together to form a continuous hollow tube to allow water and mineral ions to move easily through
• strengthened by spirals of lignin to withstand pressure of water moving

Question 12

phloem function

Answer 12

carries dissolved food from leaves around the plant

Question 13

phloem adaptations

Answer 13

• Cell walls between the cell break down form special sieve plates.
• Allow water carrying dissolved food to move freely up
• Lose a lot of their internal structures
• Mitochondria transfer energy needed to move dissolved food up and down the plant in phloem

Question 14

state two differences in structure between palisade cells and spongy mesophyll cells

Answer 14

• palisade cells have more chloroplasts
• palisade cells are elongated mesophyll cells

Question 15

Describe the structures in a leaf that enable a plant to photosynthesise

Answer 15

• Chloroplasts are the most abundant in upper layer where more sunlight is received
• Stoma allows for CO2 to enter for photosynthesis
• Air spaces in spongy mesophyll allow CO2 to reach photosynthesising cells

Question 16

Explain other structural features which are further adaptations to maximise photosynthesis in most leaves

Answer 16

• stem supports leaves and flowers
• most leaves are broad to absorb lots of sunlight for photosynthesis
• most leaves are thin to reduce distance over which CO2 has to diffuse in order to reach photosynthesising cells
• branching network of xylem tissues in a leaf delivers water to cells that need it for photosynthesis

Question 17

word equation for photosynthesis and respiration

Answer 17

Photosynthesis:
carbon dioxide + water —> (sunlight) glucose + oxygen
Respiration:
glucose + oxygen —> CO2 + water + energy