Transcript 2.6 The need for transport

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
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• 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.
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
Waxy cuticle
Palisade
mesophyll
Spongy
mesophyll
Guard Cell
Guard Cell
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
leafy cutting
Airtight
seal
A Bubble Potometer
Reservoir (zeroing
mechanism)
bubble
water
scale
•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.
A Bubble Potometer
leafy cutting
Airtight
seal
Reservoir (zeroing
mechanism)
bubble
water
scale
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:
Cardboard
Lamp
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)
High Intensity
Low intensity
End volume
(ml)
Change in
volume (ml)
Results
• Class results
Change in volume (ml)
Group
Light
Intensity
High
Intensity
Low intensity
1
2
3
4
5
Average
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
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D
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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
Coronary Arteries
• The heart is made up of
four chambers separated
by valves.
• These are the right and
left, Atria and Ventricles.
Lungs
Body
• The right hand side of the
heart pumps deoxygenated
blood while the left side
pumps oxygenated blood.
The Heart
Coronary Arteries
Aorta
Pulmonary Artery
Pulmonary
Veins
Vena
cava
Thick
muscular wall
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
Vena
cava
R. Atrium
R. Ventricle
Pulmonary
Artery
Lungs
Body
Aorta
L. Ventricle
L. Atrium
Pulmonary
Vein
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.
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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
u
Mucus producing cells
• 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.
• 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
For respiration/Energy/to make ATP
High
Low
Carbon dioxide
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 function
Structure
Oesophagus
Stomach
Small intestine
Large intestine
Liver
Pancreas
Gallbladder
Function
Structures and function
Structure
Function
Oesophagus
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.
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.
Villi
Each Villus wall
is only 1 cell
thick. There
are
approximately
4-5 million Villi
in the small
intestine.
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:
Time (mins)
Starch test
Glucose test
0
15
30
• 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
Starter
Starter
Salivary gland
Gall bladder
Large Intestine