Plant Nutrition and Transport

active transport

the movement of materials through a cell membrane using energy

chlorophyll

A green pigment found in the chloroplasts of plants, algae, and some bacteria

chloroplast

An organelle found in plant and algae cells where photosynthesis occurs

diffuse

When particles spread out from a region of higher concentration to a region of lower concentration.

equilibrium

In chemical reactions, a situation where the forward and backward reactions happen at the same rate, and the concentrations of the substances stay the same.

palisade mesophyll

Plant tissue containing closely packed cells in the upper layer of a leaf.

phloem

The tissue in plants that transports the products of photosynthesis, including sugars and amino acids.

photosynthesis

A chemical process used by plants to make glucose and oxygen from carbon dioxide and water, using light energy. Oxygen is produced as a by-product .

spongy mesophyll

The plant tissue in a leaf which has loosely packed cells and air spaces between them to allow gas exchange.

starch

A type of carbohydrate. Plants can turn the glucose produced in photosynthesis into starch for storage, and turn it back into glucose when it is needed for respiration.

stomata

Tiny holes in the epidermis (skin) of a leaf. They control gas exchange by opening and closing and are involved in loss of water from leaves. Singular is stoma.

transpiration

The loss of water from leaves by evaporation through the stomata.

xylem vessels

Narrow, hollow, dead tubes with lignin, responsible for the transport of water and minerals in plants.

yield

The amount of crops harvested from a certain area.

6CO2 + 6H2O → 6O2 + C6H12O6

Photosynthesis balanced equation

Glucose functions in the plant

- Respiration (making ATP)

- Stored as Starch

- Turned into Cellulose (cellulose is a polymer of glucose)

- Used to make fats and oils

Photosynthesis limiting factors

Temperature, light intensity, carbon dioxide or chlorophyll availability

Optimum photosynthesis

Maximum rate of photosynthesis

plateau

When the graph line goes flat (horizontal), no increase in y.

positive correlation

as one increases, the other increases

Cuticle

waxy layer on the outer surface of the epidermis of leaves and stems

guard cells

open and close stomata

Nitrate

used to make amino acids for use in plant proteins

Magnesium

Forms part of the chlorophyll molecule

Potassium

Essential for cell membranes

Phosphate

Essential part of DNA and cell membranes

Oxygen bubbles

Can be collected or counted to indicate the speed of photosynthesis

Iodine

Test for starch, turns from brown to black.

Ethanol

boil leaves in ethanol before conducting the iodine test

Limewater

A chemical that goes cloudy when carbon dioxide is bubbled through it.

diffusion distance

the greater the distance over which diffusion must occur, the longer it takes

Unicellular

Made of a single cell

Diffusion

Movement of molecules from an area of higher concentration to an area of lower concentration.

Multicellular

Made up of more than one cell.

amino acids

The building blocks that make up a protein molecule.

capillary tube

Glass tubing which is very narrow inside.

cohesive

Able to stick together.

cytoplasm

The liquid and organelles (not including the nucleus).

evaporation

The process in which a liquid changes state and turns into a gas. This cools a surface.

impermeable

A substance which fluids are unable to pass through.

ion

Electrically charged particle, formed when an atom or molecule gains or loses electrons.

mass

The amount of matter an object contains. Mass is measured in kilograms (kg) or grams (g).

osmosis

The movement of water molecules across a selectively permeable membrane from a region of higher water concentration to a region of lower water concentration.

phloem

The tissue in plants that transports the products of photosynthesis, including sugars and amino acids.

photosynthesis

A chemical process used by plants to make glucose and oxygen from carbon dioxide and water, using light energy. Oxygen is produced as a by-product of photosynthesis. Algae subsumed within plants and some bacteria are also photosynthetic.

water potential

Mmeasure of the tendency of water molecules to move from one place to another. During osmosis, water moves through a partially permeable membrane from high water potential (low solute concentration) to low water potential (high solute concentration).

root hair cell

A specialised cell that increases the surface area of the root epidermis to improve the uptake of water and minerals.

stomata

Tiny holes in the epidermis (skin) of a leaf. They control gas exchange by opening and closing and are involved in loss of water from leaves. Singular is stoma.

translocation

The transport of dissolved material within a plant.

transpiration

The loss of water from leaves by evaporation through the stomata.

turgid

Enlarged and swollen with water. Having turgor. Description of a plant cell in which the vacuole has swollen due to water gain by osmosis

vascular bundles

Groups of xylem and phloem tissue in a plant.

xylem vessels

Narrow, hollow, dead tubes with lignin, responsible for the transport of water and minerals in plants.

SA:Vol

Surface area to volume ratio. Needs to be a high number for good diffusion. (30:1 is better than 2:1)

active transport

Energy-requiring process that moves material across a cell membrane against a concentration difference

mesophyll

Spongy tissue in the interior of the leaf where most chloroplasts are found.

evaporation

Liquid to gas

rate of transpiration

increased by environmental factors: warmer temperature, more wind and low humidity

Name and describe the process used by root cells to absorb mineral ions

active transport / active uptake; low to high conc. / against conc. gradient / eq;

Name the process by which a plant loses water

transpiration / evaporation / diffusion

Describe how Steven should set up the potometer and how he should then use it to estimate the rate of water loss from the leafy shoot.

1 cut under water;

2 water tight / air tight / seal / eq; 3 how bubble introduced;

4 dry leaves / eq;

5 measure distance bubble moves / length of bubble eq;

6 scale / ruler / cm / eq;

7 time / second / minute / hour / day; 8 repeat;

Explain the change in water loss when wind was increased

blows water away / removes water / eq; (maintains) diffusion gradient / conc. gradient / eq;

Explain the change in water loss when light intensity was reduced

stomata close

Explain the change in water loss when half of the leaves where removed

less surface / area;

(fewer) idea of reduced number of stomata / pores;

What is meant by the term transpiration?

evaporation / loss of water / diffusion;

surface of plant / stomata / from leaves / from plant / eq;

Suggest why a polythene bag was put around the pot of soil

stop water loss (from soil) / stop evaporation (from soil) / water can only be lost through plant / eq;

Explain how the structure of the root hair cell is adapted to absorb water from the soil

1. large surface area;

2. permeable membrane;

3. osmosis / diffusion;

Explain how plants absorb water from the soil and transport the water to their leaves.

1. osmosis;

2. dilute solution to concentrated solution / eq; 3. root hair cells;

4. xylem;

5. transpiration / evaporation / diffusion of water

from leaves;

Some useful substances are dissolved in the water that is taken up by plants. Name one of these substances.

mineral / mineral ion / salt

Give two environmental conditions you could vary in the laboratory when investigating the rate of water uptake by a leafy shoot.

For each condition describe how you could obtain a range of different values.

1. wind + how varied / eq;; eg fan at high and low speed

2. light + how varied / eq;; eg lamp close and far

3. humidity + how varied / eq;; eg clear plastic bag

4. temp + how varied / eq;; eg air conditioning / room thermostat

Explain how the rate of transpiration is affected by changes in the environment

1. high humidity decreases rate; 2. reduced concentration

gradient / eq;

3. high wind increases rate ;

4. increased concentration gradient / eq;

5. high temperature increases rate ; 6. more (kinetic) energy /

more evaporation / eq;

7. high light increases rate ; 8. stomata open / eq;

Name two substances that are transported in the xylem

1. water;

2. minerals / ions / salts / named mineral ion / eq;

Plants obtain their food by the process of photosynthesis.

Explain how the structure of the leaf is adapted for its role as the organ of photosynthesis. (6)

large surface area;

thin (leaf);

upper epidermis / cuticle; transparent / lets light through; chloroplasts / chlorophyll; palisade (mesophyll);

close to surface;

absorb light;

spongy (mesophyll);

diffusion;

stomata / guard cells;

carbon dioxide;

xylem;

water; ignore if transpired

Describe how one named mineral ion helps plants to grow

named ion;

eg. nitrate / magnesium / phosphate / sulphate / iron / potassium / calcium

use of ion; - magnesium for chlorophyll production

Describe how magnesium ions are used to help trees to grow

chlorophyll / chloroplasts; photosynthesis / absorb light / eq

Describe how the structure of a leaf is adapted to absorb carbon dioxide

stomata / guard cells; spongy (mesophyll) / spongy (layer) / air spaces / eq; moist;

thin;

large surface area

A simple controlled experiment can be carried out to show that a plant leaf produces starch when exposed to light.

At the start of the experiment, all of the starch should be removed from the leaf. Suggest how this could be done.

dark for 12 hours plus;

Describe how you would test a leaf for starch.

Include the safety precautions you would take and the results you would expect to see.

boil/heat/warm in ethanol/alcohol

safety: water bath / no flame / eq; iodine;

blue black

Describe the role of chloroplasts in leaf cells

(trap/absorb) light / eq;

chlorophyll;

photosynthesis / starch / glucose / eq

Write the word equation for photosynthesis

Carbon dioxide + water = glucose + oxygen

Name four abiotic (non-living) factors likely to affect the rate of photosynthesis

Carbon dioxide

temperature / heat;

(sun)light / light intensity;

wavelength / colour;

water / rain;

minerals / ions / salts / named mineral / nutrients

What are magnesium ions used for in plants?

chlorophyll / chloroplast

What are nitrate ions used for in plants?

1. amino acids / protein / enzymes; 2. growth;

3. DNA / bases;

4. chlorophyll / eq;

Name two carbohydrates found in plants

1. starch; 2. glucose; 3. cellulose; 4. sucrose; 5. fructose

The production of tomatoes is affected by an insect pest called the tomato leaf miner. The photograph shows a tomato leaf that has been damaged by the tomato leaf miner.

The adult female leaf miner lays eggs on tomato leaves that develop into maggots (larvae). These maggots feed on leaf mesophyll tissue inside the leaf.

Explain how feeding on mesophyll tissue will affect tomato production.

1. lower production / fewer fruit / less growth / eq; 2. (fewer) chloroplasts / less chlorophyll;

3. (less) photosynthesis;

4. (less) carbohydrate / glucose / starch;

Name the gas given off during photosynthesis

Oxygen

How does upper epidermis help leaf with photosynthesis

transparent / lets light through / no chloroplasts

How does palisade layer help leaf with photosynthesis

idea of many / lots of chloroplasts;

densely packed / aligned vertically

absorb / take in / trap light

How does spongy mesophyll layer help with photosynthesis

Air spaces

Diffusion

Xylem/vascular bundle

Transport water

How do guard cells and stomata help with photosynthesis

Open/close

Let in carbon dioxide / water loss

Water lilies float on the surface of ponds. Guard cells are found on the upper surface of a water lily rather than the lower surface.

Suggest a reason for this adaptation

1. lower surface in water / upper surface exposed to air;

2. allows carbon dioxide in

3. allows transpiration / evaporation / water loss

Experiments can be done to demonstrate that light, chlorophyll and carbon dioxide are needed for photosynthesis.

Testing leaves for starch is the final step in these experiments.

Explain what other steps need to be taken to demonstrate that each of these factors is needed for photosynthesis.

(i) light

(ii) chlorophyll

(iii) carbon dioxide

i. 1. place one leaf in light / no cover of leaf;

2. place one leaf in dark / cover part of leaf;

ii. 1. use variegated leaf / eq;

2. draw pattern of chlorophyll and compare results / test white and green parts / eq;

iii. 1. NaOH / soda lime / KOH;

2. absorb / remove carbon dioxide