Download Plant Structure Questions Answers

PLANT STRUCTURE QUESTION ANSWERS
1. How does the vascular system enable leaves and roots to function together
in supporting metabolism of the entire plant?
The vascular tissue in the roots carries water that is absorbed from the soil
through the stem and to the leaves to support photosynthesis and
metabolism. The sugars are then transported down the stem in the phloem.
and to the nonphotosynthesizing cells to support their metabolism. Nutrients
stored in the roots over winter are dissolved in water and transported via
the phloem upwards to supply the growing buds.
2. Cells in lower layers of your skin divide and replace dead cells that slough
off the skin’s surface. Are such regions of cell division comparable to a
plant meristem? Explain.
Yes, a cork cambium produces a tough outer layer of bark that serves to
protect the tree as it grows wider.
3. In what year of growth would you expect an annual plant to flower?
A biennial plant? Year 2 , second summer
A perennial herb? Every year
A tree? After an initial 1-3 year growth.
4. What two systems have evolved in vascular plants to allow them to obtain
resources from the environment?
Root systems and stem/leaf systems.
5. In what plants would you find a tap root? A fibrous root?
A tap root is found in eudicots, a fibrous root system in monocots
6. What is the function of root hairs?
Root hairs are expansions from the root periderm layer that serve to
increase the surface area of the root to increase the plants ability to
absorb nutrients from the soil.
7. What are the functions of roots?
Absorb nutrients from the soil and anchor the plant.
8. How does the presence of an apical bud affect growth of axillary buds on a
branch.
An apical bud will grow and make the plant taller. Its presence acts to
suppress the growth of axillary buds along the stem. As the apical buds
moves farther up the tree (or if it is damaged), the axillary buds growth is
no longer suppressed, and they will elongate to form side branches.
9. Describe the structure and give an example of
A stolon, a rhizome, a tuber, and a bulb
Stolon – Horizontal stems such as in a strawberry or spider plant.
Rhizome, a thick horizontal stem that grows on the top or just below the soil
surface (ginger, iris)
Tuber – an underground swollen stem (potato)
Bulb – an underground vertical stem consisting of swollen bases of leaves.
(onion, daffodil)
10. What types of leaves would you expect to find a petiole? (eudicot) A
sheath? (Monocot)
11. Draw an opposite leaf pattern, an alternate leaf pattern, and a whorled leaf
pattern.
12. Draw and label a section of a stem showing nodes, internodes, apical
meristems, and axillary meristems.
13. Explain what is meant by apical dominance? How does pruning affect apical
dominance and stem growth beneath the cut?
Apical dominance refers to the how substances produced in the apical
meristem of a shoot inhibits / prevents the growth of axillary buds located
further down on the same shoot. Apical dominance causes the shoot to grow
taller without putting any energy into side branches. When the apical
meristem is cut off, axillary buds will begin to grow, producing a plant with
side branches. This results in a fuller plant.
14. Compare and contrast the characteristics of the three tissue systems in
plants.
Dermal tissue – single layer of tightly packed cells on the surface of a plant.
Root hairs and stomata are specialized dermal tissue.
Vascular – found within the plant, they are a network of specialized tube like
cells. The xylem moves water upwards in the plant. It contains two types of
cells, tracheids and vessels. Both are dead at maturity.
The phloem is made up of sieve tubes that lack some organelles and their
companion cells. They are alive at maturity and carry organic matters up and
down the plant.
Ground tissue is all other types of cells in plants.
15. Compare the structure and function of parenchyma, collenchyma, and
sclerenchyma.
Parenchyma – usually just contain primary walls, and as a result, are
relatively thin and flexible. Perform most of the metabolic functions of the
plant such as photosynthesis and storage of starch.
Collenchyma cells have unevenly thickened primary cell walls. (thicker walls
than parencymya but thinner than schlerenchyma). They are often grouped
into strands and are located just below the epidermis, providing support but
not restricting growth. Flexible and living, they are able to elongate as the
plant grows.
Sclerenchyma.- have thick secondary walls containing lignin for added
strength. Rigid and cannot elongate. Found in regions of the plant that have
stopped growing. Many are dead at maturity.
16. What two types of cells make up the xylem? Describe the
structure/characteristics of each type of cell.
Tracheids – long thin cells with tapered ends, have secondary walls
strengthened with lignin so they add to support of plant.
Vessels – generally wider, shorter, and thinner walled than tracheids. They
are aligned more end to end.
All xylem are dead at functional maturity.
17. What type of cell is found in phloem? Describe the structure /
characteristics of this cell type.
Sieve tube elements are alive at maturity but lack a nucleus, ribosomes, and
a distinct vacuole. They have sieve plates at their ends to allow flow of
organic materials and fluid between cells. Each has a companion cells that
does contain all its organelles, and which serves to assist the sieve tube in
functioning.
18. Sketch a diagram showing the location of vascular tissue in a monocot stem,
a eudicot stem.
19. Label a diagram of the cross section of a leaf.
20. Explain how the casparian strip in the endodermis affects movement of
water into the roots vascular system. Water and its dissolved nutrients are
absorbed into the roots by both traveling through the cells cytoplasm and by
just moving along the extracellular space. However, water reaches the
endodermis MUST enter the cytoplasm of a cell to move past the casparian
strip (that blocks water moving past it through the extracellular space)
before it may enter the xylem in the central vascular tissue of the root.
21. Compare movement of substances through the symplast with movement of
substances through the apoplast.
The apoplast consists of the areas outside of the plasma membrane. It
includes the cell walls and intercellular spaces. Substances moving through
the apoplast do not need to pass through a plasma membrane.
The symplast consists of cytoplasm and plasmodesmata (tiny tubes
connecting cytoplasm of neighboring cells). Substances moving through the
symplast must first enter the cell by moving through the plasmamembrane.
22. Label and compare diagrams of a root (cross section) of a monocot vs
eudicot (dicot)
23. Compare primary and secondary growth:
 Result of each
Primary growth is from apical meristems in roots and stems and elongates
the plant, making roots longer and stems taller.
Secondary growth occurs in woody plants and is the result of cell division
in lateral meristems (vascular cambium and cork cambium), and makes
their stems grow thicker. Secondary growth of xylem forms wood in
trees.
 Where each is initiated
Primary growth is initiated in the root and shoot apical meristems.
Secondary growth is from the lateral meristems that include the vascular
cambium and the cork cambium layers.
24.
Eggs are found in the ovary
Pollen are produced in the anther section of the stamen
A mature ovary develops into the fruit.
Sepals protect the flower bud before it blooms.
Petals attract pollinators
The pistil (AKA carpel) is the female part of the plant.
The Stigma is a sticky surface that receives the pollen.
The ovary contains the ovules, which produce the eggs.
25.
Explain the bulk flow (cohesion-tension) theory of water from roots to
leaves.
The cohesion-tension theory states that water is obtained in plants from soil
due to the fact that water is cohesive and so is able to be drawn up from soil
particles into the root hairs via osmosis. Water is then able to move through
the root cortex cells , through the endodermis and into the xylem. The
reason water is able to travel up the xylem is due to the tension created
when water leaves the plant by evaporating into the spongy mesophyll air
spaces, then escapes through the stomata. This loss of water through the
leaves is called transpiration. As the water molecules evaporate, another
water molecule moves into its place. The water molecules are attached to
one another through cohesion, all the way down the plant, from the roots to
the leaf cells.
26.
27.
28.
29.
30.
A
B
C
C
D
31.
32.
33.
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35.
D
C
C
E
D