Plants, Structure and Function of Leaves, and Microscope Use
Vocabulary
What I think this means
Anthocyanin
Blade
Botany
Carotene
Chlorophyll
Chloroplasts
Compound Leaf
Coniferous
Deciduous
Epidermis
Guard Cells
Herbaceous
Human Anatomy and
Physiology
Margin
Midrib
Organ
Palisade Cells
Petiole
Shrub
Simple Leaf
Spongy Cells
Stipule
Stoma
Tissue
Transpiration
Vein
Vine
Xanthophyll
Zoology
What I know this means
Biology – 2 Greek words
o Bios = __________
o -logy = study of
So biology means….__________________________________
Three Major Fields of Biology
 Botany – study of ___________
 Human Anatomy and Physiology – study of the structure and function of the
_________ _________
 Zoology – study of ____________
Why Study Biology?
o You are living
o The food you eat is/was living
o You are ______________ by living things
BOTANY
Why Study Botany?
o All of our __________ comes from plants (about 2/3 directly from plants
and about 1/3 from animals who eat plants)
o Many drugs and _______________ used in medicines come from plants
o Many plants and plant products are vital to _____________
Parts of a Plant
1. _______________ – the reproductive part of the plant.
o Not all plants have showy flowers and some plants don’t have any
flowers at all. Most plants with flowers will produce ______ and
________.
2. _______________ – the ________ factory of most plants.
o Leaves go through ______________ to produce sugar for the plant.
o There are many different types of leaves.
3. _______________
o Holds up the leaves and flowers.
o It also _____________ substances and can transport food.
There are four main groups of plants based on the type of ________:
1. ________ – single, tall, woody stem
2. _________ – several low woody stems
3. ________ – non-woody plant (herbaceous stem)
4. ________ – woody or herbaceous; grows along the ground or has
tendrils that help it climb
4. _______________ –
o _____________ the plant into the ground.
o It _____________ water and nutrients for plant growth
o ______________ food.
There are two types of root systems:
1. _____________ system – the primary root grows straight ________ and
stays larger than secondary roots (ex: carrot, dandelion)
2. ____________ root system – the primary root remains _________ and
many secondary roots grow out in all directions (ex: grass)
Label the diagram:
Special Leaves
Special leaves have a special design for a __________ ________. These are
considered leaves because buds appear by them and they have the same tissue
structure of leaves.
Examples:
o ____________ – special leaves that coil around support structures
o ____________ – on cacti; lack chlorophyll
o Leaves of Venus flytrap, sundew, pitcher plant, bladderwort –
designed to trap and digest insects
Special Stems
Some stems are mistaken for roots because of their location.
o ____________ – runners that aid in asexual reproduction (strawberries)
o ____________ – horizontal stems that grow underground (ginger, iris)
o ____________ – swollen ends of rhizomes that store food (potatoes)
o ____________ – vertical underground shoots that store food (onions)
The External Structure and Function of Leaves
Organism Hierarchy
o
o
o
o
o
o
Molecules
Cells
Tissues
Organs
Systems
Organism
Plant Hierarchy
o Molecules – ________________________________________ + others
o Cells – Plant cells with differing __________________
o Tissues – Structural, vascular, meristematic
o Organs – Leaf, stem, flower, root
o Systems – __________ and ___________
o Organism – Plant
Plant Systems
What is a system?
A group of structures designed to function together as a unit to perform a
_____________ ________ for the organism.
2 types of systems:
1. __________ system – the part of the plant ordinarily _______________;
organ involved - roots
2. __________ system – the part of the plant which is usually found above the
ground; organs involved – stem, leaves, flower
Leaf Parts
o
o __________ – flat, green portion of the leaf
o __________– leaf stalk (leaves that lack a
petiole are sessile leaves)
o __________– edge of a leaf
o __________– carry sap through a plant
o __________– small leaf-like structure that
covers a leaf as it is growing
o __________– bottom edge of a leaf
axil - the angle between the
upper side of the stem and a leaf
or petiole.
lamina - the blade of a leaf.
leaf apex - the outer end of a
leaf; the end that is opposite the
petiole.
midrib - the central rib of a leaf it is usually continuous with the
petiole.
petiole - a leaf stalk; it attaches the
leaf to the plant.
stem - (also called the axis) the main
support of the plant.
stipule - the small, paired appendages
(sometimes leaf-life) that are found at
the base of the petiole of leaves of
many flowering plants.
vein - one of the many vascular
structures on a leaf. Veins provide
supports for the leaf and transport
both water and food through the leaf.
Three Basic Leaf Types
o _________, flat leaves: roses, dandelions, maples, lilacs
o _________, narrow leaves: grasses, lilies, onions, palms
o _________-like or _________-like leaves: pines, firs, cedars, spruces
Variety in Leaf Shapes
o Broadleaf leaves can be oval, elliptical, heart-shaped, arrow-shaped,
oblong, ovate, and many other types
o Needle-like leaves can be ___________ or in ____________. This is an
important feature to use to identify them.
Variety in Leaf Margins
Three main types of leaf margins are:
1. Entire – ___________ and ____________
2. Toothed – small or large “_______________”
3. Lobed – _______________ that stick out
Simple vs. Compound Leaves
o Simple leaves have ___________ blade on every petiole
o Compound leaves have _______ than ________ blade on every petiole
o Compound leaves can have a variety of arrangements
Leaf Arrangements
o Leaves are arranged so that all leaves on a stem will have maximum
_____________ to _____________
o Leaves have many different arrangements:
(Vocab– a node is the point where a leaf grows from the stem)
 __________________
When _______ __________ grow from the same node
Attach at right angles to the leaves directly above and below them
Ex: maple, mint, coleus
 _________________
Only ________ leaf grows from each node
The leaves alternate sides as they go up the branch.
Ex: apple, oak, birch
 ________________
______________ or more leaves grow from each node
Ex: loosestrife, Easter lily
 ______________ (Basal)
Cluster of leaves grow around the base of the plant
Usually a plant with a
rosette arrangement
doesn’t have a stem
Ex: dandelion
Leaf Venation
Venation = pattern of veins in a leaf
1. Parallel – veins are ______________ to each other
2. Pinnate – one ____________ vein with smaller veins extending
3. Palmate – 2 or more major veins extending outward from _________ point
Evergreen vs. Deciduous
Evergreen – foliage remains green _________-round
Deciduous – sheds leaves ______________
Coniferous – bears ____________; usually evergreen
o Some examples of deciduous conifers: bald cypress, European larch,
ginkgo
o Evergreen broadleaf trees also exist, normally in the tropics.
Tropism = a plant’s ______________ to external stimuli
Phototropism: Individual leaves will orient themselves so that each blade is at
approximately a 90o angle to the light. The petiole twists because there is more
growth on the side that doesn’t have the light.
o Phototropism – the growth response of a plant stimulated by ________
o Hydrotropism – response to ___________ (roots grow toward water)
o Thigmotropism – response to ___________ (ex: vines wrap around a
pole, sensitive plant)
o Geotropism – response to __________; can be positive or negative
(positive – roots grow down; negative – stem grows up
o Heliotropism – _____-tracking (ex: sunflowers)
LEAF ANATOMY From: http://www.biologycorner.com/worksheets/leaf_coloring.html
The leaf is the primary photosynthetic organ of the plant. It consists of a flattened portion,
called the blade, that is attached to the plant by a structure called the petiole. Sometimes
leaves are divided into two or more sections called leaflets. Leaves with a single undivided
blade are called simple, those with two or more leaflets are called compound.
The outer surface of the leaf has a thin waxy covering called the cuticle (A), this layer's primary
function is to prevent water loss within the leaf. (Plants that leave entirely within water do not
have a cuticle). Directly underneath the cuticle is a layer of cells called the epidermis (B). The
vascular tissue, xylem and phloem are found within the veins of the leaf. Veins are actually
extensions that run from to tips of the roots all the way up to the edges of the leaves. The outer
layer of the vein is made of cells called bundle sheath cells (E), and they create a circle around
the xylem and the phloem. One the picture, xylem is the upper layer of cells (G) and is shaded a
little lighter than the lower layer of cells - phloem (H). Recall that xylem transports water and
phloem transports sugar (food).
Within the leaf, there is a layer of cells called the mesophyll. The word mesophyll is Greek and
means "middle" (meso) "leaf" (phyllon). Mesophyll can then be divided into two layers, the
palisade layer (D) and the spongy layer (F). Palisade cells are more column-like, and lie just
under the epidermis, the spongy cells are more loosely packed and lie between the palisade
layer and the lower epidermis. The air spaces between the spongy cells allow for gas exchange.
Mesophyll cells (both palisade and spongy) are packed with chloroplasts, and this is where
photosynthesis actually occurs.
Epidermis also lines the lower area of the leaf (as does the cuticle). The leaf also has tiny holes
within the epidermis called stomata. Specialized cells, called guard cells (C) surround the
stomata and are shaped like two cupped hands. Changes within water pressure cause the
stoma (singular of stomata) to open or close. If the guard cells are full of water, they swell up
and bend away from each other which opens the stomata. During dry times, the guard cells
close.
Color the structures underlined above. Make sure that the entire picture is colored and that the
color matches the words. For simplicity only part of the picture is labeled.
Questions:
1. What two tissues are found within a vein?
2. What does the word "mesophyll" mean?
3. What two layers of the plant contain chloroplasts?
4. The outermost layer of cells: _________________________
5. The waxy covering of the leaf.: _______________________
6. These cells function to open and close stomata. _____________________
7. Outer layer of the vein: ________________________
8. Column like cells that lie just under the epidermis. ___________________
9. Openings that allow for gas exchange. _________________________
10. The stalk that connects the leaf to the stem. ______________________
Cuticle (light blue)
Epidermis (yellow)
Guard cells (pink)
Palisade Mesophyll
(dark green)
Phloem (purple)
Xylem (orange)
Spongy Mesophyll
(light green)
Bundle Sheath
(dark blue)
Cell Structure
Most cells have three basic parts.
o Cell membrane – ________________ the inside of a cell from the outside
o Nucleus – ___________ ___________ in the cell
o ________________ – A mixture of fluid and organelles between the
nucleus and the cell membrane
Plant cells have some components that are not found in animal cells.
o Cell ________ – A rigid layer outside the cell membrane that gives structure
to a plant cell; made of cellulose
o Chloroplasts – Contain the pigment _____________; absorb energy from
the ________ for photosynthesis
o Vacuole – A _____________ area inside of the cell (found in some animal
cells)
PHOTOSYNTHESIS and CELLULAR RESPIRATION
Photosynthesis
o
o
o
o
Purpose – Make __________ for the plant
Occurs – in the _________________
Photosynthesis – “putting together with ___________”
All plants that go through photosynthesis have chloroplasts
regardless of their color. Photosynthesis takes place in the
chloroplasts.
o It’s estimated that plants produce ____ billion tons of food each year.
Formula for Photosynthesis
Two Phases of Photosynthesis
o __________ Phase – Requires light
o _________ Phase – Doesn’t require light, but can happen in the light
Light Phase
o ________ energy is converted into the chemical energy of ATP and NADPH.
o _______________ absorbs the solar energy.
o Water, ADP, and NADP are _____________ for the reaction.
o ATP, NADPH, and oxygen are the _____________.
o Energy from the sun ______ the water molecule into hydrogen and oxygen.
o Hydrogen is used to make NADPH.
o Oxygen will later be released.
o ATP and NADPH _________ energy.
Dark Phase
o Happens in the light, but does _________ require light energy
o The dark phase is known as the Calvin cycle
o 2 3-carbon molecules combine to make _________. C and O come from
the carbon dioxide. H comes from the NADPH.
o The energy to do this comes from ATP breaking down into ADP and NADPH
breaking down into NADP+.
What Affects Photosynthesis?
o _____________ of water
o Temperature _____________ (ph. occurs best at 32-95o F)
o Poor light intensity
o Shortage of ___________ ___________
Stages of Sugar
o ____________ – form of sugar as it is made in a plant
o ____________ – form of sugar as it is transported; formed by glucose and
fructose molecules attached; this is why sap tastes sweet
o ____________ – form of sugar as it is stored; complex carbohydrate; many
sugar molecules are joined together
* Fructose – same chemical formula as glucose, but arranged differently
Cellular Respiration
o Cellular respiration is the process by which food __________ is released in
the presence of ___________
o This occurs in the _________________
o In plants and animals this requires __________ and ___________
o Gives off carbon, water, and energy
o Three parts: glycolysis, Krebs cycle, electron transport chain
 Glycolysis
 One molecule of glucose is broken into two 3-carbon molecules of
pyruvic acid
 2 molecules of ATP provide the ___________
 4 molecules of ATP end up being produced
 Krebs Cycle
 In a series of reactions, pyruvic acid is broken down into _________
_____________
 NADH, FADH2, and ATP are formed
 High energy electrons are also produced
 Electron Transport
 The ____________ are used to convert ADP into ATP
 Totals
 One glucose molecule can produce ______ ATP molecules after it
goes through cellular respiration
 Without oxygen, glucose can only produce ____ ATP molecules
during glycolysis and none during the Krebs cycle and electron
transport (without oxygen, cells complete either alcoholic
fermentation or lactic acid fermentation)
FALL COLORATION and WILTING
Why Do Leaves Turn Colors?
 The changes in the fall are triggered by the change in ____________.
 The __________ _________forms between the base of the petiole
and the stem.
 This ________ materials from being able to go in and out of the leaf.
 This causes the chlorophyll to begin to _________________.
Plant Pigments
 When the chlorophyll deteriorates, other pigments that were hidden
by the chlorophyll are now able to be seen.
o Chlorophyll – ________ colors
o Xanthophyll – ____________ colors
o Carotene – _______________________ colors
o Anthocyanin – bright _______, ________, and _______ colors
Falling Leaves
 The enzyme cellulase weakens the cell wall of the abscission layer.
 The leaf will break off under its own weight or with the help of wind
 A protective layer of _______ cells forms at the base of the petiole
producing the _______ scar on the branch
Water and Wilting
 Not all water taken in by the plant is used.
 Much of it escapes through _________________
 Factors that affect the rate of transpiration:
o
o
o
o
o
o
_______________
Temperature
Intensity of ______________
Wind speed
Amount of CO2 in the air
Amount of soil water available
 The _________ ________ are important in controlling the rate of
transpiration
 When there is a lot of water in the plant, the guard cells become
turgid and the stoma ________
 When water is moving out of the guard cells faster than it can be
replaced, the guard cells ________ the stoma
Wilting
 Wilting occurs when _______ transpiration is occurring than water
getting into the plant.
 Temporary wilting may occur on a hot day when a plant is in the sun.
The sun causes more water to be _____ than the plant can get from
its _______. When the plant is in the shade, it is able to catch up and
the cells become turgid again.
 In ____________ wilting, there is usually a drought or poor retention
of soil water so the plant cannot replace any of the water lost
through transpiration.
Questions
Not all of the answers are directly in the note packet. You may need to do some thinking!
1. Explain the origin of the word biology. (root words and language)
2. What are the functions of the stem, root, flower, and leaves?
3. Differentiate between a fibrous root and a taproot.
4. Why would grass be better than dandelions for stopping erosion?
5. Describe the two plant systems and which organs they contain.
6. What are the three basic leaf types?
7. What are the three categories of leaf margins?
8. How can you distinguish between compound and simple leaves?
9. Draw an example of each of the different leaf arrangements: opposite, alternate, rosette, and
whorled.
10. Draw an example of each of the different venations: parallel, palmate, pinnate.
11. Differentiate between deciduous and evergreen trees.
12. Describe two types of tropisms.
13. Why are palisade cells located near the top of a leaf?
14. What are xylem and phloem?
15. How are gas exchange and water loss controlled in a plant?
16. How are the cell membrane and the cell wall different?
17. What is the advantage to an organism that can make its own food?
18. How do green plants obtain sunlight?
19. Why is carbon dioxide needed for photosynthesis?
20. What are the two reactants and the two products of photosynthesis?
21. How many water molecules are split at once? Why?
22. What are the three reactants and the three products of the light phase?
23. What is the dark phase also called? Where does it get energy?
24. List the four factors that affect the rate of photosynthesis and describe how each affects the
rate.
25. What are the three forms of energy in a plant and what is the purpose of each?
26. What is the purpose of cellular respiration?
27. What triggers leaves to change colors?
28. What are the four basic leaf pigments and what colors do each produce?
29. What is the purpose of the abscission layer?
30. What is transpiration?
31. Name three factors that affect the rate of transpiration.
32. What is the difference between temporary and permanent wilting?