Chapter 3

Question 1

Photosynthesis

Answer 1

The process by which light energy from the sun is converted to sugars

Question 2

Transpiration

Answer 2

The loss/release of water vapor from the leaf by evaporation through the stomata

Question 3

Respiration

Answer 3

Exchange of CO2(coming in) and Oxygen (going out)

Question 4

Tendrils

Answer 4

A type of modified leaf that wrap around objects for support

Ex) Grape vines

Question 5

Spines.

Answer 5

A type of modified leaf for protection

Thorns or spikes

Question 6

Bracts

Answer 6

Green or colored leaves that surround flowers. Ex: Poinsettia

Question 7

Mesophyll

Answer 7

(Parenchyma tissue)
‘Middle’ of the leaf. There are two types..

Palisade: contain most of the chloroplasts in dicot leafs

Spongy: next to the intercellular air spaces to allow for the interchange of gases.
Most monocots only have this type
Dicots have both

Question 8

Vascular bundles

Answer 8

Tissues that transport materials to and from the leaf

Xylem and phloem

Question 9

Epidermis

Answer 9

Outer layer of leaf. Upper and lower epidermis. It’s translucent

Epidermal cells are clear to allow light penetration

Question 10

Cuticle

Answer 10

Waxy layer usually produced by upper epidermis, also prevents moisture loss through epidermis

Question 11

Stoma (stomata)

Answer 11

Opening in leaf; surrounded by two guard cells.
-stomata controls transpiration and air exchange rates

• mostly found in lower epidermis and occasionally in upper epidermis (for dicots)
• monocots have lower and upper stomata

Question 12

Hydrathodes

Answer 12

Modified stoma

(Overflow holes)

• openings on leave margins at the end of veins that transpire water droplets instead of vapor
• this type of water secretion is called “guttation”

Often mistaken for dew

Question 13

Trichomes

Answer 13

Hairlike projections that some leaves have.

For
•protection
•warmth in cold climates
•deflecting hot sun

Described at pubescence

Question 14

Why are leafs green?

Answer 14

Chlorophyll is abundant in the leaf cells during the growing season

The chlorophylls green color dominates and masks out the colors of any pigment that may be present in the leaf

Question 15

Why do leaves change in autumn?

Answer 15

• leaves lose chlorophyll as dormancy or death sets in (senescence)
• The chromoplast are always present in the leaf now show through and oranges reds purples yellows,etc.

Question 16

Chromoplasts

Answer 16

Color plastid that are often found in many flower petals and fruits and dominate in some colored leaves

These are the non-green pigments

Question 17

Leaf arrangements on the stem

Answer 17

• opposite-two leaves and auxiliary buds at the same node directly across from each other
• alternate-leaves and auxiliary bud’s occur one per node on varying sides of the stem
• subopposite-almost opposite but a little Offset
• whorled-three or more leaves and auxiliary buds are attached at the same node

Question 18

Petiole

Answer 18

The part that attaches the leaf to the stem

Question 19

Blade of the leaf

Answer 19

The main part of the leaf that houses mesophyll