Life processes in Plants and Animals

Question 1

How many cotyledons are in a dicotyledon?

Answer 1

2

Question 2

Name 5 tissue systems

Answer 2

1. Parenchyma
2. Collenchyma
3. Sclerenchyma
4. Epidemal tissue
5. Xylem and Phloem (Vascular tissue)

Question 3

What is Parenchyma

Answer 3

A packaging tissue

Question 4

5 characteristics of Parenchyma

Answer 4

1. Least specialized cells
2. Contains a protoplast therefore living
3. Rounded with inter cellular air spaces between adjacent cells
4. Thin and flexible cellulose walls
5. Has a central vacuole surrounded by a layer of cytoplasm which contains amyloplasts

Question 5

What are amyloplasts

Answer 5

membranous sacs containing starch grains

Question 6

Where is Parenchyma tissue found?

Answer 6

Mesophyll of leaves (internal layer)
Cortex of roots and stems ( outer layer)
Pith of stems (innermost part)
Pulp of fruits
Endosperm of seeds

Question 7

Functions of Parenchyma

Answer 7

Metabolic functions
Providing support and shape
Storage of food and water
Chlorenchyma contains chloroplasts for photosynthesis

Question 8

Where is Collenchyma found?

Answer 8

Under the epidermis

Bordering large veins in leaves

Question 9

Characteristics of Collenchyma

Answer 9

Living elongated cells that run parallel to the lenght of plant organs
Have primary cells walls of cellulose that are unevenly thickened, especially thick at the corners

Question 10

What role does Collenchyma play in plant support

Answer 10

Young plants support new growth regions
Older stems of non-woody (herbaceous) plants allow plant to stand erect
Leaves to allow them to present flat, horizontal surface for exposure to direct rays of sun

Question 11

Where is sclerenchyma found

Answer 11

Anywhere in plant, especially in vascular tissue

Question 12

Characteristics of Sclerenchyma

Answer 12

Very elongated and slender
Evenly, thickened lignified secondary walls
Dead and empty at maturity

Question 13

What role does Sclerenchyma play in support?

Answer 13

Provides tensile strength because of lignified walls

Question 14

What is tensile strength

Answer 14

Resistance of a body to tensile forces that ten to pull apart

Question 15

What is the epidermis

Answer 15

Outermost layer of living cells covering the root, stem, leaf, flower, fruit and seed parts.

Question 16

Name the functions of modified epidermal cells

Answer 16

Root hairs- increase surface area for absorption
Cutin is excreted to form a cuticle which prevents water loss
Guard cells- control opening and closing stomata to regulate the loss of water vapor during transpiration.

Question 17

What does vascular tissue consist of

Answer 17

Xylem and Phloem

Question 18

How is vascular tissue organized in stems and roots

Answer 18

In roots, they form a single central vascular cylinder

In stems, they form various vascular bundles

Question 19

What cells does Xylem consist of

Answer 19

Tracheids,vessels,xylem parenchyma and fibers

Question 20

Characteristics of Tracheids

Answer 20

Long and cigar-shaped, ends overlapping
Thick cells contain lignin
Dead and hollow at maturity
Connected by pits

Question 21

Definition of lignin

Answer 21

A complex polymer deposited in cell walls which makes them woody and relatively rigid

Question 22

Characteristics of Vessels

Answer 22

Arise from series of cylindrical cells end-to-end known as vessel elements
Xylem vessel- a hollow continuous non-living tube
Has a wide diameter
Walls are thick and strong
Lignified cellulose walls laid in spirals,rings, and plates
Xylem vessels have pits to move water laterally

Question 23

Functions of xylem tissue

Answer 23

Transport water and dissolved minerals

Acts as supportive tissue

Question 24

How does Xylem support the plant

Answer 24

Gives strength and support due to xylem being lignified and Arranged in a ring
Provides flexibility