Structures of Plants (Chapter 7) Flashcards Preview

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Flashcards in Structures of Plants (Chapter 7) Deck (22)
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1
Q

What is the epidermis?

A

A continuous layer on the outside of the plant, one cell thick, that provides protection

2
Q

What is the epidermis covered with in stems and leaves?

A

A waterproof waxy cuticle which helps to protect the organ from drying out and from infection

3
Q

What does the epidermis have in laves?

A

Stomata, which are pores that allow entry of CO2 for photosynthesis

4
Q

What does the epidermis have in roots?

A

Extensions called root hairs to increase the surface area for absorption of water and mineral salts

5
Q

What is the parenchyma made up of?

A

Thin-walled cells which are used as packing tissue

6
Q

Describe 3 characteristics of the cells in the parenchyma

A

1) they are very metabolically active
2) may be used for storage of foods e.g. starch
3) when they are turgid, they help to support the plant, preventing wilting

7
Q

What do air spaces in the parenchyma allow?

A

Gas exchange

8
Q

How are water and mineral salts transported in the parenchyma?

A

Through the walls and living contents of cells

9
Q

What does the parenchyma form in roots and stems?

A

The cortex (outer region of cells)

10
Q

What does the parenchyma form in stems?

A

The pith (central region of stems)

11
Q

What does the parenchyma contain in leaves and what is it modified to form?

A
  • It contains chloroplasts

- It is modified to form palisade and spongy mesophyll

12
Q

What is the collenchyma?

A

A modified form of parenchyma with extra cellulose deposited at the corners of cells, providing extra strength

13
Q

Where is collenchyma in leaves?

A

In the midrib of leaves

14
Q

Describe the endodermis

A

One cell thick and surrounds the vascular tissue (xylem and phloem) in stems and roots

15
Q

What is the mesophyll made up of?

A

Specialised parenchyma cells found between the lower and upper epidermis of the leaf

16
Q

What are the two types of mesophyll?

A

Spongy and palisade

17
Q

What do mesophyll cells contain and therefore what are they specilaised for?

A

They contain chloroplasts ∴ they are specialised for photosynthesis

18
Q

Where in the leaf are palisade mesophyll cells and why?

A

Near the upper surface of the leaf where they receive more sunlight ∴ they contain more chloroplasts than spongy mesophyll cells

19
Q

What does spongy mesophyll contain?

A

Many large air spaces between cells

20
Q

What is the pericycle?

A

A layer of cells just inside the endodermis and next to the vascular tissue

21
Q

Describe the pericycle in roots

A

One cell thick and new roots can grow from it

22
Q

Describe the pericycle in stems

A

Formed from sclerenchyma (a tissue with dead lignified cells for extra strength)

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