Key area 6-The Need for Transport

Plant transport systems

Learning Intention: To learn the structures and functions involved in the transpiration process.

Success Criteria: Identify the structures and their function in transpiration.

Transpiration• Transpiration is the evaporation of water into the

atmosphere from leaves and stems of plants.

• Water moves from the roots of a plant to the leaves.• Water is vital for the transport of minerals within a

plant and for photosynthesis.• Water is lost through pores, called Stomata, that are

on the underside of a leaf.

• Plants have various tissues and structures that help the movement of water and materials around them.

Transpiration

Xylem and phloem vessels in the stem

The transpiration stream pulls water from the roots up to the leaves just like this.

Transpiration-Roots• Water taken in by

the roots. Root Hairs increase the surface area for the absorption of water from the surrounding soil.

• Water moves into the root hair cells by osmosis.

• The water builds pressure in the tissues and helps to ‘push’ the water up the plant.

A

J

Transpiration-Xylem• Once water has been

absorbed into the plants it is carried by Xylem tissue towards the leaves for photosynthesis. (upwards)

• Water and dissolved minerals (eg, Na, K) travel in Xylem.

• It is dead tissue.• The Lignin rings help keep

the Xylem tissue open.

• Like a straw in a glass, the water ‘sticks’ the side of the Xylem which helps it move upwards against gravity

Phloem• Phloem tissue is not

directly linked to the transpiration stream.

• They are situated next to Xylem tissue within a plant.

• Unlike Xylem, Phloem tissue is alive and carries sugars and organic molecules all around the plant. (upwards and downwards)

Microscopes• Using Plant structure 1 slides-

• Slide numbers 1, 2, 3, 5, 7, 8, 12 show structures in plants that involved in transpiration.

• Root hairs, Xylem and Phloem can all be seen.

• Task- Draw your field of view for at least 4 of the different slides.

Transpiration- Leaves

Epidermis

Guard Cell

Guard Cell

Waxy cuticle

Palisade mesophyll

Spongy mesophyll

Leaves• Why is the cuticle waxy?• Cuticle and Epidermis reduces water loss, by

evaporation, from the surface of the leaf.

• Water is needed in the leaves so the (palisade) mesophyll cells can photosynthesise.

• The opening and closing of the stomata are controlled by the guard cells. They swell with water to open and empty of water to close.

• The stomata allow CO2 to diffuse into the plant and O2 to diffuse out.

Measuring Transpiration

Reservoir (zeroing mechanism)

bubble

water

leafy cutting

Airtight seal

scale

A Bubble Potometer

Reservoir (zeroing mechanism)

bubble

water

leafy cutting

Airtight seal

scale

A Bubble Potometer

•A bubble is introduced to the capillary tube.

•As water is taken up by the plant and lost from the leaves the bubble moves along the scale.

•By comparing the start and end position of the bubble, it is possible to measure the transpiration rate.

Capillary tube

Factors affecting transpiration

• The transpiration rate of a plant can be affected by environmental conditions:-

• Light intensity• Temperature• Humidity• Wind speed• Water supply

• The transpiration rate can be increased by:- high light intensity, increase in temperature, increase in wind speed and a decrease in humidity.

• These all increase the rate of water vapour lost through the stomata of a leaf.

Investigating transpiration

Aim: To investigate how light intensity affects the transpiration rate of a geranium leaf.

Equipment:• Measuring cylinder, 2 glass beakers, plasticine,

geranium leaf, lamp, cardboard.

Diagram:

Lamp

Cardboard

Geranium

Beakers sealed with plasticine

200ml water

Method:Day 1

• Collect your equipment.• Measure 200ml cold water using the measuring cylinder and

add to one of the glass beakers.• Cut one geranium leaf. Ensure the stem is left as long as

possible.• Place a small hole at the centre of a square piece of card using

a sharp pencil.• Push the geranium stem through the hole and seal the hole on

the top and bottom of the card using a small piece of plasticine.• Place the card and leaf on top of the beaker containing the

water. Ensure that the stem of the leaf is in contact with the water.

• Rest the second beaker upside down on top of the first and plug the spout openings with more plasticine.

• One pair position a lamp 20cm from the beaker and switch on and one pair leave the beaker in room conditions.

• Leave the apparatus overnight.

Method:Day 2

• Observe the beakers. Do you notice any changes?

• Use a measuring cylinder to measure the volume of water left in the bottom beaker.

• Is this volume the same as the volume at the start? Why or why not?

• What has happened to the water that has been lost?

• Write up your experiment in a scientific way using a title, aim, diagram, method, results table and conclusion.

Results

• Group results.

Light Intensity

Start volume(ml)

End volume(ml)

Change in volume (ml)

High Intensity

Low intensity

Results

• Class results

Change in volume (ml)

Group

LightIntensity

1 2 3 4 5 Average

High Intensity

Low intensity

Animal transport systems

Learning Intention: To learn the structures and functions of the circulatory system.

Success Criteria: Identify the structures and their function in a healthy system.

Starter

Starter

C D E

Animal Transport• In mammals the transport and exchange of

nutrients and gases occurs through out the body.

• To allow this to occur the mammalian body has a complex network of transport pathways.

• The three main body systems we’ll focus on are the Circulatory, Respiratory and Digestive systems.

• Do you know what each of these systems does??

Circulatory system• The circulatory system is made up of the heart,

blood and blood vessels.

• Its main function is to transport oxygen and nutrients to the cells of the body.

• The heart pumps the blood.• The blood is carried in the vessels.• The blood carries the oxygen, carbon dioxide and

waste and nutrients.

Heart structure• The heart is made up of

four chambers separated by valves.

• These are the right and left, Atria and Ventricles.

• The right hand side of the heart pumps deoxygenated blood while the left side pumps oxygenated blood.

Lungs

Body

Coronary Arteries

The Heart

Aorta

Vena cava

Pulmonary Artery

Pulmonary Veins

Thick muscular wall

Coronary Arteries

Heart Dissection

• Pig heart dissection-

• Heart Dissection

Blood vessels

• There are three types of blood vessel found in the body.

• Arteries- carry blood away from the heart.• Veins- carry blood towards the heart.• Capillaries- connect arteries and veins.

• The main arteries and veins connected to the heart are the Aorta, Vena Cava, Pulmonary Arteries and Veins and the Coronary Arteries

Arteries

•Arteries have a pulse – this is the movement of blood being pushed out of the heart along an artery.

•Arteries have thick muscular walls to cope with the blood travelling under high pressure.

Veins

• Veins carry blood under lower pressure so have thinner muscular walls.

• Veins have valves to prevent the backflow of blood.

Capillaries• Capillaries allow exchange of materials between the blood and the cells of the body (O2, glucose).

• Capillaries are only one cell thick to allow easier/quicker diffusion of materials.

•Capillaries also provide a large surface area for exchange.

Blood Composition

• Blood is made up of three main parts: – plasma– red blood cells – white blood cells

• Plasma is the liquid part of blood that carries many substances such as sugars, salts, amino acids, proteins, vitamins, water, carbon dioxide and urea.

Pathway of blood•The pathway of blood

through the heart, lungs and body follows the path shown in the diagram opposite.

•You should be able to start at any point and name the chambers and blood vessels that the blood travels through.

Pathway of blood

Body

Vena cava

R. Atrium

R. Ventricle Pulmonary Artery

Lungs

Pulmonary Vein

L. Atrium

L. Ventricle

Aorta

Transport of oxygen

• Oxygen is carried by red blood cells by binding to a molecule called haemoglobin.

• This forms oxyhaemoglobin.

• It has a protein and non protein part.

• Haemoglobin contains Iron within the haem group.

Polypeptide (protein) Haem group

(non-protein)

Transport of oxygen• The structure of a red blood cell aids its ability to

carry oxygen.• It has a biconcave shape increasing surface area.

• It has no nucleus, why?• Contains more haemoglobin and therefore able

to carry more oxygen.

Animal transport systems

Learning Intention: To learn the structures and functions of the respiratory system.

Success Criteria: Identify the structures and their function in a healthy system.

Starter

Starter

To stop backflow of blood.

P M

Respiratory system• The respiratory system is

made up of a series of tubes.

• The largest is the trachea.

• The trachea is held open by rings of cartilage. Why?

• The trachea branches into two bronchi (1 bronchus)

• Each bronchus divides into smaller bronchioles.

• Bronchioles end in tiny air sacs called alveoli.

Lung Dissection

• Video to add

Respiratory System• The trachea contains

cartilage rings to prevent it from sticking closed.

• A bit like lignin in xylem vessels!

• Mucus is produced to trap dirt and bacteria.

Mucus producing cells

u

• Cilia are hair like projections that move the mucus up to back of the throat to be swallowed or spat out. •Alveoli are the site of gas exchange.

Alveoli• These are the site of gas

exchange.• Oxygen diffuses into the

bloodstream and carbon dioxide diffuses out of the blood into the air sacs.

• The alveoli are adapted to be efficient at this process:- how?

• They have very thin membranes,

• A large network of blood capillaries,

• A moist lining, which allows gases to dissolve,

• A very large surface area.

Animal transport systems

Learning Intention: To learn the structures and functions of the digestive system.

Success Criteria: Identify the structures and their function in a healthy body system.

Starter

Starter

Diffusion

HighLow

Carbon dioxide

For respiration/Energy/to make ATP

Digestive system• The digestive system, or alimentary canal, runs

from the mouth to the anus,• Various organs make up the alimentary canal and

some organs are known as accessory organs.

• The alimentary canal includes the oesophagus, stomach, small intestine and large intestine.

• The accessory organs that aid digestion are the liver, pancreas and gall bladder

Structures and functionStructure Function

Oesophagus

Stomach

Small intestine

Large intestine

Liver

Pancreas

Gallbladder

Structures and functionStructure FunctionOesophagus Connects mouth to the stomach. Digestion already

started in the mouth.

Stomach Acid and enzymes continue digestion. Stomach muscles help churn the food with the digestive juices.

Small intestine Site of absorption. Contains villi to increase surface area for absorption

Large intestine Site of water absorption. Waste passes onto rectum.

Liver Produces bile, site of deamination, stores glycogen, removes toxins from blood.

Pancreas Produces hormones (insulin, glucagon) and digestive enzymes (lipase, amylase, trypsin).

Gallbladder Stores bile.

Peristalsis• How does food move through

our digestive system?

• Food is moved through the alimentary canal by a process called peristalsis.

• Muscles behind the food contract and muscles in front of the food relax.

• This occurs throughout the digestive system.

Small intestine• The small intestine is the site

of absorption of digested food.

• It has various adaptations that make it efficient at doing this.

• The small intestine is very long(5-8m) and contains many villi which increases the surface area for absorption too take place.

• Villi are finger-like projections lining the small intestine.

VilliEach Villus wall is only 1 cell thick. There are approximately 4-5 million Villi in the small intestine.

The lacteal absorbs products of fat digestion (fatty acids/ glycerol).

The blood vessels provide a good blood supply to aid absorption of glucose and amino acids.

Model Gut experiment• The following experiment represents how the small

intestine functions. (The visking tubing is the intestine, the water is the blood.)

• The lining or membrane, of the small intestine is selectively permeable.

• This means only certain, small, soluble molecules are able to diffuse across the lining of the small intestine.

• Eg, glucose, water, amino acids

Model Gut experiment• Aim: To show membranes are selectively permeable.

• Method:

1. Soak a 20cm long piece of visking tubing in water to soften. Tie a knot in one end.

2. Using syringes, add 10ml of starch and 10ml of glucose solution to the visking tubing bag.

3. Tie a knot in the other end, trim excess tubing to 1cm length and wash thoroughly under running water.

4. Place the bag in a boiling tube and fill the remaining space with water.

5. Immediately remove a few mls of water using a dropper.

6. Put 2 drops in a dimple on a spotting tile and the rest in a small test tube.

7. Add iodine to the spotting tile. Add Benedicts to the small test tube and place in a the water bath at 90°C.

8. Repeat steps 6 and 7 after 15 minutes and 30 minutes.

Model Gut experiment• Results:

• What do you think will happen? Why?• Starch should remain in the visking tubing and

glucose should diffuse out.• Starch is a large complex molecule and is to big to

pass through the membrane.• Conclusion: now write out your own conclusion

Time (mins) Starch test Glucose test

0

15

30

Starter

Starter

Salivary gland

Gall bladder

Large Intestine