2.1 Plant cells & tissues

Question 1

Function of: Cell Wall

Answer 1

Outer layer - controls shape of the cell

Provides strength and rigidity

Protects against pathogens

Question 2

Function of: Cell Membrane

Answer 2

Located just inside Cell Wall.

Contains and encloses cell contents and produces the cell wall.

Selectively-permeable to control what passes in and out of a cell

Question 3

Function of: Cytoplasm

Answer 3

Jelly-like substance inside the Cell Membrane

Contains most of the organelles, and also dissolved minerals and nutrients

Question 4

Function of: Chloroplasts

Answer 4

Organelles in a cell which trap light energy to conduct photosynthesis.

Question 5

Function of: Mitochondria

Answer 5

Site of respiration

They break down sugars to release energy

Question 6

Function of: Vaculoles

Answer 6

Pockets of water - store minerals, pigments or waste products

Aid in cell expansion and rigidity (turgor)

Question 7

Function of: Endoplasmic Reticulum

Answer 7

Wavy, sheet-like structures that surround the Nucleus

A factory that makes proteins and other structures;

Also makes new cell membranes and hormones

Question 8

Function of: Nucleus

Answer 8

Contains DNA which controls cell processes and metabolism

Initiates cell devision and codes for the characteristics of the plant

Question 9

Function of: Chromosomes

Answer 9

Arranged bodies of DNA within the Nucleus

Contain coded information for the cell.

Question 10

Where is cell division located within a plant?

Answer 10

In the Meristems

Apical meristem is present in shoot and root tips (root apical meristem and shoot apical meristem)

Lateral meristem is present on lateral sides of stems and roots - they increase the girth/thickness of the plant.

Vascular cambium and cork cambium are examples of lateral meristematic tissues

Question 11

How do plants increase in size?

Answer 11

Through cell division (sited at meristems)

Through cell expansion

Differentiation is the third process - when cells modify to perform certain functions

These three combined processes lead to formation of plant tissues.

Question 12

What does the term, “Plant Tissue” mean?

Answer 12

A group of similar cells performing a specific function or purpose

(Many different types of tissues combine to form many different complex organs (e.g. leaves, stems etc))

Question 13

TWO characteristics and TWO functions of: Epidermis

Answer 13

Characteristics:

Outermost layer of tissue with surface wax (cuticle)

May have specialised cells - e.g hairs/guard cells

Functions:

Protection from pests/diseases

Prevention of water loss

Gas exchange

Question 14

TWO characteristics and TWO functions of: Cambium

Answer 14

Characteristics:

Found in stems and roots.

A layer of meristematic cells

Functions:

Forms xylem and phloem;

Allows dicots to become thicker by laying down secondary xylem and phloem.

Question 15

TWO characteristics and TWO functions of: Phloem

Answer 15

Characteristics:

Located in vegetative tissues

Forms part of the vascular tissue.

Functions:

Food transport tubes (sugars/ carbohydrates)

Structural

Question 16

TWO characteristics and TWO functions of: Xylem

Answer 16

Characteristics:

Forms part of the vascular tissue

Formed of dead, tube-shaped cells

Functions:

Water and nutrient transport from roots to leaves;

Forms wood for strength and support

Question 17

TWO characteristics and TWO functions of Parenchyma

Answer 17

Characteristics:

Made from simple cells that are generally rounded;

Has thin cell walls and large vacuoles.

Functions:

“Packing tissue” for maintaining shape through turgor;

May have specialised function - e.g. starch storage

Question 18

Cortex: function and location

Answer 18

Packing tissue in roots and stems

Sits just beneath the epidermis

Question 19

Endodermis: function (1) and location (2)

Answer 19

Controls the uptake of water & dissolved nutrients

Located in roots

Innermost layer of the cortex

Casparian strip also located here

Question 20

Pericycle: function and location

Answer 20

Layer of meristematic cells that produces lateral roots.

Located in roots, between endodermis and vascular tissue - outermost layer of stele.

Question 21

Packing tissue location & characteristics:

Answer 21

E.g. parenchyma and cells in the pith, cortex and mesophyll.

Thin cell walls

Air spaces between cells

Living cell contents

Storage for starch

Contain chloroplasts for photosynthesis

Question 22

Meristematic tissue location and characteristics:

Answer 22

Location: apical meristems of shoots and roots, vascular cambium.

Unspecialised cells

Capable of cell division

Tightly packed together

Small vacuole

Contain numerous mitochondria