2.1 Plant cells & tissues Flashcards
Function of: Cell Wall
Outer layer - controls shape of the cell
Provides strength and rigidity
Protects against pathogens
Function of: Cell Membrane
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
Function of: Cytoplasm
Jelly-like substance inside the Cell Membrane
Contains most of the organelles, and also dissolved minerals and nutrients
Function of: Chloroplasts
Organelles in a cell which trap light energy to conduct photosynthesis.
Function of: Mitochondria
Site of respiration
They break down sugars to release energy
Function of: Vaculoles
Pockets of water - store minerals, pigments or waste products
Aid in cell expansion and rigidity (turgor)
Function of: Endoplasmic Reticulum
Wavy, sheet-like structures that surround the Nucleus
A factory that makes proteins and other structures;
Also makes new cell membranes and hormones
Function of: Nucleus
Contains DNA which controls cell processes and metabolism
Initiates cell devision and codes for the characteristics of the plant
Function of: Chromosomes
Arranged bodies of DNA within the Nucleus
Contain coded information for the cell.
Where is cell division located within a plant?
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
How do plants increase in size?
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.
What does the term, “Plant Tissue” mean?
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))
TWO characteristics and TWO functions of: Epidermis
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
TWO characteristics and TWO functions of: Cambium
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.
TWO characteristics and TWO functions of: Phloem
Characteristics:
Located in vegetative tissues
Forms part of the vascular tissue.
Functions:
Food transport tubes (sugars/ carbohydrates)
Structural
TWO characteristics and TWO functions of: Xylem
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
TWO characteristics and TWO functions of Parenchyma
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
Cortex: function and location
Packing tissue in roots and stems
Sits just beneath the epidermis
Endodermis: function (1) and location (2)
Controls the uptake of water & dissolved nutrients
Located in roots
Innermost layer of the cortex
Casparian strip also located here
Pericycle: function and location
Layer of meristematic cells that produces lateral roots.
Located in roots, between endodermis and vascular tissue - outermost layer of stele.
Packing tissue location & characteristics:
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
Meristematic tissue location and characteristics:
Location: apical meristems of shoots and roots, vascular cambium.
Unspecialised cells
Capable of cell division
Tightly packed together
Small vacuole
Contain numerous mitochondria
