Lesson 6 Plant cells, Tissues, and Organs

A- What you need to know?A1. How can cell differentiate from one another?

A2. What are meristem cells? Where are they?

A3. What is tissue?

A4. Organize cells, tissues, organs, organism according to complexity

A5. Basic structures of plant organs (leaves, stem, root and flower) + main functions

A6. Types of tissues in plants

B- Cell shapes and sizes

B1.Do all cell have the same shape and size?

B2. No

B3. Expect these cells to have the same functions?

B4. Not likely

C-The reasons for the differences in cells

C1. Result of mitosis? C2. Two identical new cells with same

set of DNAC3. But cells don’t have the same

functions and shapes (from previous slide). What causes the differences?

C4. The reason: cell differentiation and cell specialization

C- The reasons for the differences in cells (cont.)

C5. As cells differentiate (=making itself different from other cells), it becomes specialized in a particular functions

C6. Cells are specialized based on?

C7. - the proteins they contain

C8. What code for proteins?

C9. - answer: genes code for proteins

C12- But aren’t all cells have the same set of genes as a result of mitosis, how are different proteins are made in different cells?

C11. Answer: - not all genes are turned on in any given cell

- One set of genes is turned on in one cell type while another set of genes is turned on in another cell type.

C- The reasons for the differences in cells (cont.)

D- Cell, tissue, organ and systems

D1. Cells = smallest units of lifeD2. Tissue = group of specialized cellsD3. Organ = combination of several types

of tissue working together to perform a specific function

D4. Organ systems = combination of many organs working together to keep the organism alive

D5. Organism = contain all the above

E- Organizing

cells, organs,

organism, tissue with increasing complexity

An organism (e.g. a person, a plant, etc)

Plant cells

Stem

Root

Leaves

F- Organizing

cells, tissues, organ,

organism in plant

F1. Leaves, stem, root and flower are plant organs

Plant tissues: dermal, ground and vascular bundles

G- Whole plant = the organism

G1. What is it that help plants push upward, downward and outward?

http://www.progressivegardens.com/knowledge_tree/plantphys.html

H1.Meristems are cells that form specialized cells in plantsH2.These meristem cells constantly produce new cells, which then become specialized and form 3 different types of tissues in plants (next slide)H3.Plants can push upward, downward thanks to meristems

H- Specialized cells and tissues in plants

- Meristems at root tip

I-Where can we find meristems in plants?I1. Root tip (seen in previous slide)

I2. Terminal (end) and lateral (side) bud

J-Meristem cells make all of these following tissues systems

Meristem cells

Epidermal cell

groups of epidermal cells form DERMAL TISSUES

Photosynthetic cells GROUNDTISSUE

Supportcell

(thick cell wall)

VASCULAR TISSUE

Show Cell division + differetiation +specialization occur

K- 3 types of tissues in plantTypes of Tissue system and functions

Tissue location

1.Dermal Tissue System• protection• prevention of water loss

BarkLeaf surface

2.Ground Tissue System• photosynthesis• food storage• regeneration • support• protection

Leafroot

3. Vascular Tissue System• transport of water and minerals• transport of food

Stem Root

L- What are the organs in plants?

L1- Leaves, stems, root and flower

M- Plant organs- The leaf

M1. Which process occur here?M2.PhotosynthesisM3. Why is leaves thin and flat?M4. Thin so light can penetrateM5. Flat for a large surface area so photosynthesis can take place efficiently

M- The leaf (cont.)

M6. Describe photosynthesis in leaves with chemical equation?

CO2 + H2O C6H12O6 + O2

M7. Any excess glucose in leaves is stored as starch

M8. Starch is insoluble in water

N - Leaf cross section

N1-A guard cell and its stomata

Upper leaf Function1. Cuticle prevent water from evaporate

2. Epidermis tissue protect leaf, not perform photosynthesis

Middle leaf Function

1. Mesophyll tissueconsists of palisade tissue cells and spongy

parenchyma cells

1a. Palisade tissue cells

perform photosynthesis, have lots of chloroplasts inside. Lots of mitochondria as well for cellular respiration

1b. Spongy parenchyma

below palisade tissue. Contain loosely pack cells. This creates spaces like a sponge to store water vapour, O2, CO2 for photosynthesis

4. Vascular bundlesmade up of xylem and phloem; form veins that acts like

water and nutrient pipes that deliver to all cells in leaf

Lower leaf Function

1. Epidermis also the layer that protects leaves. Contain guard cells

2. Guard cells

Every 2 guard cells creates an opening called stomata which allow CO2 to enter leaves and O2 and water vapour to exit the leaves. Many guard cells across leaf's lower surface

O- Chloroplast: where PS occurs

P- Zoom in at the chloroplast

P1.Chloroplast: a double membraned organelle contains many light trapping molecules called chlorophyllsP2.Photosynthesis occurs at the thylakoid membrane

Q- Leaf adaptation

Dessert Cacti

Giant water lily

Carnivorous plant Venus fly trap

R-The Stem (or shoot)R1. 2 main functions:

physical support + transportation of water, nutrients and sugar

R2. Vascular bundles: consists of xylem (tissue) and phloem (tissue) that helps transport water and nutrients in plants

R3. Grouping xylem and phloem tissues together helps strengthen the stem.

S- Vascular bundles = xylem + phloem

S1. Xylem cells: are dead tubule cells, stacked end-to-end-hollow pipes transport water from roots to other parts of plant

Stem cross section

S- Vascular bundles = xylem + phloem (cont)

S2. Phloem cells: S3. living tubule cells, also joined end to end but smaller diameter than xylem.S4. Transport sugars from leaves to other parts S5. Have porous cell wall that allows materials to pass through between neighbouring cells Stem cross

section

T- Stem (cont.)T1. Terminal bud: where most active growth

occurs

T2. Lateral bud: is dormant (inactive); but can start to growth into new branches, leaves and flowers.

U- The rootU1. Function:U2 - anchor plantU3 - take up water and minerals from soilU4 - storage placeU5- prevent soil erosion

U6- Also contain xylem and phloem used to transport water, nutrients through plants

U- Root (cont.)

Cortex

Components of root

Location/functions

Cortex cellsdo not have chlorophyll. Cells can store starch

Endodermis

Cell layer outside the pericycle.

Their membranes regulate types and amounts of materials root can absorb

Pericyle

Outermost layer of the vascular bundles. Contain meristem cell that can form branch root

Root caphelps protect meristem cells

at root tip from damages

Root hair absorb water

V- Types of roots1 -Taproot:V1. Can reach far underground for waterV2. Anchor plant firmly in the groundV3. Plants with this type of root are harder to

pull out- E.g. dandelion root2. Fibrous root:V4.Near soil surfaceV5.Cover large surface area to look for water

right under soil surfaceV6. helps prevent soil erosion and landslides.

W-Flower= plant reproductive organ

W1.Flower contains very light weighed pollens (producing sperms) and ovules (producing eggs)

W2. Pollination (= fertilization): sperms of one plant meet the eggs of another plant

W3. How do most plant accomplish pollination?Insect, wind, human

W4. Plants that do not have flowers reproduce asexually from pre-existing stem or root. Eg. Banana, strawberry

X- Plant under attackX1. By whom?

X2. Viruses, bacteria, fungi and insects

X3. Not all plant diseases are harmful (from a human’s perspective)

X4. Eg. Rembrandt tulips have stripes pattern thanks to virus infection

Tobacco mosaic virus

Y-Plant gallY1. Gall in plant = tumour in animalY2. Abnormal group of cells keeps on dividing and form gall. Y3. Caused by attack of insects, fungi, bacteria and virusesY4. Galls do not spread to other tissues like animal tumours do

Z- Is plant a passive victim?Z1.Plants under attack protect themselves and neighbouring plants by releasing volatile chemicals into the air around themZ2. Example: tomato release chemicals into the air when being eaten by hornworms. These chemicals call a parasitic wasp to lay eggs into the body of the hornworms. Z3. The eggs hatch and feed on the caterpillar

AB-Case study- Eliminate wheat rust

AB1.Wheat rust caused by fungi that mutate frequently

AB2.Traditional treatment uses fungicide which kills the bad fungi but also beneficial fungus

AB3.Australian scientists discovered 2 genes that could help wheat combat this disease.

What technique you’ve learnt can help treat wheat rust by using the 2 newly discovered genes?

Wheat rust

• Do questions 1 & 2 page 67 in class for the case study

• Also Question 1-8 p 69

IN CLASS ACTIVITY