Lecture 11: Plant Structure

Question 1

What are the key features/functions (4) of a plant?

Answer 1

• gain energy through photosynthesis
• nutrients are absorbed through roots
• grow indeterminately
• stationary

Question 2

Define: angiosperm vs gymnosperm

Answer 2

• angiosperm: flowering plants

- gymnosperm: coniferous trees

Question 3

What is meant by phenotype plasticity?

Answer 3

the ability of one genotype to produce more than one phenotype when exposed to different environments

Question 4

What is the general function of roots(2)?

Answer 4

• nutrient uptake and plant anchoring

Question 5

Besides the main 2 general functions of plant roots, what are 3 other specialised functions of some plant species?

Answer 5

• storage (carrots and beats)
• anchoring (ivy)
• adventitious roots (roots that arise from non root tissue in response to stress conditions)

Question 6

What is meant by morphologic diversity?

Answer 6

• evolutionary adaptations to the environment

Question 7

There’s a wide diversity of leaves. Why?

Answer 7

Maximize SA while surviving environment (H2O dissapation) lead to evolutionary changes

Question 8

List the 6 modified stems we discussed in class.

Answer 8

• cactus
• thorns
• tubers
• floral mimics
• traps
• bulbs

Question 9

Explain the modified stem: cactus

Answer 9

• enlarged stem for water storage
• photosynthetic tissue on stem
• modified leaves to protect against herbivores (spiky)

Question 10

Explain the modified stem: thorns

Answer 10

• modified stem tissue to protect against herbivores

Question 11

Explain the modified stem: tubers

Answer 11

• stems grow underground and store carbs (starch like potatoes)
• nodes in stems give rise to new branches

Question 12

Explain the modified stem: floral mimics

Answer 12

• attract pollinators

Question 13

Explain the modified stem: traps

Answer 13

• trap insects

Question 14

Explain the modified stem: bulbs

Answer 14

• thickened leaves store nutrients

Question 15

Identify the structures with the red squares in the plant cell drawing

Answer 15

• see google doc

Question 16

define: plasmodesmata

Answer 16

• gaps that connect adjacent cells

Question 17

What are the 4 distinguishing structures in a plant cell that don’t exist in animals

Answer 17

• cell wall
• vacuole
• chloroplast
• plasmodesmata

Question 18

List the 3 plant tissue systems

Answer 18

• dermal
• ground
• vascular

Question 19

Explain the plant tssue system: dermal tissue

• aka
• function
• examples (3)

Answer 19

• AKA epidermis
• function: protect cell from water loss, disease, etc
• cuticle, stomata, trichomes

Question 20

Explain the plant tissue system: ground tissue

- what are the 3 types

Answer 20

• parenchyma
• collenchyma
• sclerenchyma

Question 21

Explain the plant tissue system: vascular tissue

- what are the 2 types; explain their functions

Answer 21

• xylem: transport H2O and dissolved nutrients from root to shoot
• phloem: transport sugars, amino acids, etc in both directions (root to shoot, shoot to root)

Question 22

define: trichomes

Answer 22

• hair-like structures; physical deterrance against insects

Question 23

Explain this type of ground tissue: parenchyma

Answer 23

• workhorse cells: involved in photosynthesis and storage; totipotent (can form a new plant)

Question 24

Explain this type of ground tissue: collenchyma

Answer 24

• flexible, structural support

Question 25

Explain this type of ground tissue: sclerenchyma

Answer 25

- structural support fibres: often dead tissue | - form the thick secondary wall made of lignin

Question 26

Explain: meristems

Answer 26

- undifferentiated cells that can differentiate into distinct cells with specific properties

Question 27

Define: apical meristems (location and function)

Answer 27

- located at the tip of root and shoots | - responsible for primary growth

Question 28

What are 3 types of primary meristems

Answer 28

- ground meristem: ground tissue - protoderm: dermal tissue - procambium: vascular tissue

Question 29

In a root, there are 3 zones. Can you state them and what falls under each zone?

Answer 29

- see google doc

Question 30

What is the purpose of primary growth (2)?

Answer 30

- increases length of root and shoot | - increases absorption of light and nutrients

Question 31

If shown a cross section of a root or shoot, can you identify the 3 types of tissue systems?

Answer 31

- see google doc

Question 32

What is the purpose of secondary growth?

Answer 32

- increases width of roots and shoots | - only in plants with cambium (special type of meristem; aka lateral meristem)

Question 33

define cambium

Answer 33

- special type of meristem (lateral meristem) - forms cylinder around root, branch, or tree trunk - cells grow laterally

Question 34

Do you understand the secondary plant growth that is shown on the pie wedge on the google doc?

Answer 34

- see google doc