Chapter 6

Question 1

What’s the main function of leaves?

Answer 1

Manufacturing food
Exchange gasses
Transpiration
Evaporation
Store food

Question 2

Why does plants manufacture of food?

Answer 2

help the plant to produce food
converting the energy in sunlight into chemical energy
plant can make glucose during photosynthesis.

Question 3

How does the plant exchange gases?

Answer 3

Openings, stomata, helps exchange gasses.
Day - CO2 in, O2 out
Night - O2 in, CO2 out

Question 4

What is the purpose of transpiration and evaporation?

Answer 4

Helps pull water from roots.

Help cooling the plant

Question 5

How do leaves store food?

Answer 5

In form of starch

Question 6

Of what dat the basic dicotyledonous leaf consist?

Answer 6

Leaf base
Two stipules
Petiole
auxiliary bud
Leaf blade

Question 7

Leaf base?

Answer 7

Expanded area of petiole where leaf attaches to stem.

Question 8

Paired stipules?

Answer 8

Located each side of leaf base.

Two small flaps protect young blade as develops.

Question 9

Petiole?

Answer 9

Stalk connects blade to leaf base

Inside tiny vessels, connected with veins in leaf

Question 10

Blade?

Answer 10

Major photosynthetic surface of plant, appears green.

Question 11

Veins?

Answer 11

Visible in leaf blade are vascular bundles for transport of organic molecules and inorganic substances.

Question 12

What are organic molecules?

Answer 12

Sucrose

Amino acids

Question 13

What are inorganic substances?

Answer 13

Water

Mineral ions

Question 14

Auxiliary bud?

Answer 14

Develops in axil between petiole and stem.

Potential to form shoots or flowers.

Question 15

What is a simple leaf?

Answer 15

When only single blade inserted directly on petiole.

Question 16

What is a compound leaf?

Answer 16

Blade two or more subunits: leaflets

Question 17

What are the different layers of the leaf?

Answer 17

Upper epidermis
Lower epidermis
Mesophyll
Vascular bundles

Question 18

Upper epidermis?

Answer 18

Layer transparent cells-cover up surface of leaf
Allows light to pass through mesophyll cells
Protect inner cells
Produce cuticle

Question 19

What is the cuticle?

Answer 19

Waxy layer - cover upper epidermis

Question 20

Lower epidermis?

Answer 20

Layer Transparent cells - cover lower surface leaf
Reduces water evaporation 
Allow light pass through mesophyll cells
Protect inner cells
Sometimes produce cuticle
Stomata

Question 21

Stomata?

Answer 21

Between epidermal cells
Guard cells on each side
Control opening and closing
Gaseous exchange CO2 and O2 diffuse in and out
Transpiration
Few chloroplasts some photosynthesis

Question 22

Mesophyll?

Answer 22

Between two epidermises
Top - palisade: most photosynthesis takes place
Bottom - spongy m: round, loosely arranged; air spaces between for gaseous exchange by diffusion between m cells and air.

Photosynthesis also takes place

Question 23

Vascular bundles?

Answer 23

Xylem

Phloem

Question 24

Xylem?

Answer 24

Tiny tubes - xylem vessels

Transport inorganic substances

Question 25

Phloem?

Answer 25

Transport inorganic substances. | (Translocation

Question 26

Why is Geranium a well known plant in Namibia?

Answer 26

Grow throughout Namibia Gardeners like to plant in pots Easy to get from nurseries

Question 27

Why is Elodea common?

Answer 27

Aquatic plant/waterweed Use in aquariums for O2 for fish Easy to get from fish shops

Question 28

What is the definition of photosynthesis?

Answer 28

Method of nutrition in green plants by trapping light energy in chlorophyll and producing organic substances (carbohydrates - glucose), using water, carbon dioxide with release of O2 as byproduct.

Question 29

What is the word equation for photosynthesis?

Answer 29

Carbon dioxide + water + (chlorophyll;light energy) =>glucose + oxygen

Question 30

How is the leaf adapted to carry out photosynthesis?

Answer 30

- leaf supported by petiole expose largest possible are to sunlight/air - leaf large surface area exposed to sunlight and air. Absorb max sunlight - thin allow light penetrate all cells. Diffusion quicker, reduced distance - upper - lower epidermis transparent; allow light through to mesophyll layer. - palisade m cells closely packed absorb more incident light - palisade m cells near leaf surface maximize light interception - pmc arranged at right angles, reduce number of cell walls for light to pass through - pmc large amounts of chloroplasts maximise sunlight absorption - smc round, loosely packes; accommodate air spaces-act as reservoirs for gasses and assist in gaseous in gaseous axchange - mesophyll cells large vacuoles middle; push chloroplasts to edge of cells - mesophyll cell walls thin cell walls; short diffusion pathway - chloroplasts contain chlorophyll: trap sunlight energy used to combine CO2 and H2O to make glucose - chloroplasts move in mesophyll cells towards light - chloroplasts move in mesophyll cells away from high intensity avoid damage - Xylem: present within short distances form every mesophyll cell fot transport of water to cells, some of which will be used in chloroplasts for photosynthesis. - Phloem:present in short distances from every mesophyll cell, to translocate products of photosynthesis

Question 31

What is the process of photosynthesis?

Answer 31

1. Light energy absorbed in chloroplasts, trapped by chlorophyll in chloroplasts of mesophyll cells 2. Light energy transformed to chemical energy 3. Water absorbed from soil by root hair cells - osmosis 4. Water from in root hair cells through cortex and endodermis into Xylem to leaves 5. From leaf Xylem, water by osmosis into mesophyll cells and chloroplasts 6. Chemical energy used to split water molecules hydrogen ions and oxygen 7. Oxygen released by diffusion into air spaces of leaf; then through stomata out 8. Carbon dioxide enters diffusion stomata, diffuses into air spaces 9. diffuses into chloroplasts of mesophyll cells 10. Carbon dioxide hydrogen atoms combined Carbon dioxides converts into carbohydrates, using sunlight energy 11. Forms energy rich carbohydrate molecule - glucose

Question 32

Importance of photosynthesis?

Answer 32

1. Photosynthesis sugar, oxygen. Oxygen important to survive 2. Need energy grow;reproduce. Respiration to produce ATP, used for energy. Respiration reaction uses glucose 3. Glucose used to build plant cell structures; cellulose walls 4. Glucose changes to insoluble starch, fats, oils, proteins; stored in seeds leaves roots. 5. Photosynthesis reduce CO2. Can reduce global warming

Question 33

Shade leaves?

Answer 33

Thinner, larger more surface area, more chlorophyll. More efficient in harvesting sunlight at low light levels

Question 34

Sun leaves?

Answer 34

Thicker, smaller less surface area, less chlorophyll | Develop longer palisade or an additional layer of palisade

Question 35

Why is gaseous exchange important?

Answer 35

Photosynthesis: need CO2, means disposing of O2. Respiration: need O2, means disposing CO2 Water vapor for osmosis

Question 36

How is stomata adapted for sufficient gaseous exchange?

Answer 36

Optimum size, shape distribution for efficient diffusion Surrounded by 2 guard cells, attached at each end of both cells Stomata open, spongy palisade mesophyll in continuous contact with outside atmosphere. Carbon dioxide enter by diffusion Water in mesophyll cells across cellular membranes, evaporates into air spaces, and evaporates through stomata. Oxygen exactly the same: mesophyll cells>cellular membrane>air spaces>stomata

Question 37

How have leaves adapted for efficient gaseous exchange?

Answer 37

Thin, stomata, large surface area