Download I. II. and III. Carbohydrates Structures and Plants

Carbohydrate Structure and Plants
I. Importance of carbohydrates to living things :
1. Carbohydrates – compounds made up
of carbon, hydrogen, & oxygen atoms,
usually in a ratio of 1 :2 :1, ex : sugars,
starches, & cellulose.
**Living things use carbohydrates
as their main source of energy.**
-Energy for cell activities comes
from the immediate break-down of
sugars, such as glucose.
-Extra sugar is stored as complex
carbohydrates known as starches.
3 Major Types of Carbohydrates
Monosaccharides – single
sugar molecules, ex :
glucose (tissues), galactose
(milk), & fructose (fruit).
Disaccharides – double
sugar molecules.
Polysaccharides – large
macromolecules formed from
many sugars, ex : glycogen
(animal starch), plant starch,
& cellulose.
Plants (Kingdom Plantae)
II. Introduction to Plants
Plant – multicellular
eukaryote that has a
cell wall made of cellulose.
-Plants perform
photosynthesis using
the green pigments
chlorophyll a & b.
A. Characteristics of plants
All plants :
a. Are multicellular & don’t move.
b. Are autotrophic – photosynthetic.
c. Have cell walls made of a
polysaccharide called cellulose.
d. Have chloroplasts in their cells.
e. Have alternation of generations –
life cycles that alternate between
a diploid (2N) & haploid (N)
phase.
B. Size in plants
*Size in plants depends
on whether or not it has
vascular tissue (xylem &
phloem) to transport
food, water, etc.
Vascular tissue = larger plants.
No vascular tissue = smaller plants.
III. Plant Structure & Function
A. Specialized Structures in Plants
-There are 3 principal organs of seed
plants :
1. Leaves – are the major site of
photosynthesis in plants.
-Have 3 main parts :
a. Blade – broad, flat photosynthetic
surface of a leaf.
b. Veins- vascular bundle that
transports water & food in a leaf.
c. Petiole – stalk that connects a leaf
to a stem
Stems
2. Stems – have 3 main functions :
a. Support leaves and flowers.
b. Transport water/nutrients in plant.
c. Storage (potato & starch)
Stem Woodiness
Woody stem – composed of cellulose,
layers of xylem, lignin, and pectic
substances. Produce bark.
Herbaceous stem – fleshy stems that
don’t produce bark as they grow.
Monocot vs. Dicot Stems
There are 4 main types of stems :
a. Herbaceous plant – a non-woody
plant composed of a relatively soft
green tissue covered with a thin
protective layer.
b. Shrub – hard, strong stems.
c. Vine – slender, woody stems.
d. Tree – hard, strong stems that
include a trunk, branches, & twigs.
Wood – layers of xylem that build up
year after year. Is made up of
heartwood (dark) & sapwood (light).
Bark – structure that helps prevent
water loss in plants. Is made up of
phloem, cork cambium, & cork.
Wood Composition
Roots
3. Roots – have 3 main functions :
a. To absorb water & minerals.
b. To anchor the plant.
c. To store food (carrots).
There are 2 main types of roots :
a. Taproot – a single large central
root with much smaller side
roots branching out from it.
Grow deep to “tap”
groundwater.
b. Fibrous root – a clump of short,
threadlike divisions. Found in
the upper part of the soil.
-Roots have tiny narrow tubes
called root hairs to increase the
surface area that is available for
the absorption of water.
B. Plant Tissues
1. Dermal tissue – protective or
surface tissue that forms the
outermost tissue layer on leaves
and stems.
-On leaves dermal tissue is waxy to
make them waterproof – cuticle.
-On stems dermal tissue is thick
bark, spongy cork, or tight sheath.
-Some cells of dermal tissue contain
chloroplasts, for photosynthesis.
Main function of dermal tissue : to
reduce water loss.
Vascular Tissue
2. Vascular tissue – tissue that
transports or conducts
materials around the plant.
2 Types of vascular tissue
Xylem – vascular tissue that
transports water & minerals up
the plant.
Phloem – vascular tissue that
transports food (sugars from
photosynthesis) down the plant.
Main function of vascular tissue :
transport materials.
Ground Tissue
3. Ground tissue – the
fundamental tissue in plants
(all remaining plant cells).
Main function of ground tissue :
support, especially in young &
herbaceous plants.