Transcript h) Transport - iGCSE Science Courses

IGCSE BIOLOGY
SECTION 2 LESSON 5
Content
Section 2
Structures
and
functions
in living
organisms
a) Levels of organisation
b) Cell structure
c) Biological molecules
d) Movement of substances
into and out of cells
e) Nutrition
f) Respiration
g) Gas exchange
h) Transport
i) Excretion
j) Coordination and response
Content
Lesson 5
h) Transport
h) Transport
2.49 understand why simple, unicellular organisms can
rely on diffusion for movement of substances in and out
of the cell
2.50 understand the need for a transport system in
multicellular organisms
Flowering plants
2.51 describe the role of phloem in transporting
sucrose and amino acids between the leaves and
other parts of the plant
2.52 describe the role of xylem in transporting water
and mineral salts from the roots to other parts of the
plant
2.53 explain how water is absorbed by root hair cells
2.54 understand that transpiration is the evaporation of
water from the surface of a plant
2.55 explain how the rate of transpiration is affected
by changes in humidity,wind speed, temperature and
light intensity
2.56 describe experiments to investigate the role of
environmental factors in determining the rate of
transpiration from a leafy shoot
Content
Lesson 5
h) Transport
h) Transport
Humans
2.57 describe the composition of the blood: red blood cells, white
blood cells, platelets and plasma
2.58 understand the role of plasma in the transport of carbon
dioxide, digested food, urea, hormones and heat energy
2.59 explain how adaptations of red blood cells, including shape,
structure and the presence of haemoglobin, make them suitable for
the transport of oxygen
2.60 describe how the immune system responds to disease using
white blood cells, illustrated by phagocytes ingesting pathogens and
lymphocytes releasing antibodies specific to the pathogen
2.61 understand that vaccination results in the manufacture of
memory cells, which enable future antibody production to the
pathogen to occur sooner, faster and in greater quantity
2.62 understand that platelets are involved in blood clotting,
which prevents blood loss and the entry of micro-organisms
2.63 describe the structure of the heart and how it functions
2.64 explain how the heart rate changes during exercise and under
the influence of adrenaline
2.65 describe the structure of arteries, veins and capillaries and
understand their roles
2.66 understand the general structure of the circulation system to
include the blood vessels to and from the heart, the lungs, the liver
and the kidneys.
Diffusion in living organisms
Diffusion in living organisms
In:
Food
oxygen
Diffusion in living organisms
In:
Out:
Food
Carbon
dioxide
oxygen
Waste
products
Diffusion in living organisms
Eg. movement of oxygen in Amoeba
Diffusion in living organisms
Eg. movement of oxygen in Amoeba
High oxygen
concentration
Low oxygen
concentration
Diffusion in living organisms
Eg. movement of oxygen in Amoeba
High oxygen
concentration
Low oxygen
concentration
Oxygen will move from a high concentration outside the
cell to a lower concentration inside the cell. It is moving
from high to low – i.e. down a concentration gradient.
Diffusion in living organisms
Fine for single-celled
organisms
Diffusion in living organisms
Fine for single-celled
organisms
But for bigger organisms
……….
Diffusion in living organisms
Fine for single-celled
organisms
But for bigger organisms
……….
Multi-cellular organisms
(both plants and animals)
need transport systems.
Transport in flowering plants
Water and
mineral
salts.
Roots
Transport in flowering plants
Water and
mineral
salts.
Sucrose and
amino acids.
Leaves
Products of
photosynthesis
Roots
Transport in flowering plants
XYLEM
Water and
mineral
salts.
PHLOEM
Sucrose and
amino acids.
Leaves
Products of
photosynthesis
Roots
Transport in flowering plants
XYLEM
Water and
mineral
salts.
Roots
Water (and mineral) movement into the
root
Water (and mineral) movement into the
root
More concentrated solution
inside
Less concentrated solution
outside (more DILUTE)
Water (and mineral) movement into the
root
More concentrated solution
inside
WATER
WATER
Less concentrated solution
outside (more DILUTE)
Water (and mineral) movement into the
root
More concentrated solution
inside
WATER
WATER
Less concentrated solution
outside (more DILUTE)
In root hair cells water moves
from the surrounding soil into
the cell by osmosis, along a
concentration gradient
Water (and mineral) movement into the root
Root hair cell with a high
concentration of nitrate ions.
Soil with a lower concentration of
nitrate ions.
Water (and mineral) movement into the root
When substances are moved into a cell where
there is already a higher concentration, then
ENERGY from respiration will be required.
Root hair cell with a high
concentration of nitrate ions.
Soil with a lower concentration of
nitrate ions.
Water (and mineral) movement into the root
When substances are moved into a cell where
there is already a higher concentration, then
ENERGY from respiration will be required.
Root hair cell with a high
concentration of nitrate ions.
Energy will be used to ‘pull’
nitrate ions from the
surrounding soil into the cell
Soil with a lower concentration of
nitrate ions.
Water (and mineral) movement into the root
When substances are moved into a cell where
there is already a higher concentration, then
ENERGY from respiration will be required.
Root hair cell with a high
concentration of nitrate ions.
This is Active Transport
Energy will be used to ‘pull’
nitrate ions from the
surrounding soil into the cell
Soil with a lower concentration of
nitrate ions.
Water (and mineral) movement into the root
When substances are moved into a cell where
there is already a higher concentration, then
ENERGY from respiration will be required.
Root hair cell with a high
concentration of nitrate ions.
This is Active Transport
Root hairs provide
roots with a much
greater surface
area.
Energy will be used to ‘pull’
nitrate ions from the
surrounding soil into the cell
Soil with a lower concentration of
nitrate ions.
Water movement through the plant
Water (and
dissolved mineral
salts) are moved
from the roots up
through the plant
in xylem vessels.
Water movement through the plant
Water (and
dissolved mineral
salts) are moved
from the roots up
through the plant
in xylem vessels.
Water movement through the plant
Water (and
dissolved mineral
salts) are moved
from the roots up
through the plant
in xylem vessels.
Water movement through the plant
Water (and
dissolved mineral
salts) are moved
from the roots up
through the plant
in xylem vessels.
Xylem vessels contain
a strengthening
material called lignin
and are dead. Water
movement is ‘passive’.
Leaf structure
Cross section through a leaf
Leaf structure
Cross section through a leaf
Vascular bundle
containing xylem
vessels and
phloem tubes
Leaf structure
Cross section through a leaf
Xylem
Vascular bundle
containing xylem
vessels and
phloem tubes
Phloem
Water movement through the plant
Water movement through the plant
1. Water evaporates from the
internal leaf cells through the
stomata (TRANSPIRATION)
Water movement through the plant
1. Water evaporates from the
internal leaf cells through the
stomata (TRANSPIRATION)
2. Water passes from xylem
vessels in the stem to leaf cells
by osmosis.
Water movement through the plant
1. Water evaporates from the
internal leaf cells through the
stomata (TRANSPIRATION)
2. Water passes from xylem
vessels in the stem to leaf cells
by osmosis.
3. This ‘pulls’ the water up
through the xylem to replace
that being lost.
Water movement through the plant
1. Water evaporates from the
internal leaf cells through the
stomata (TRANSPIRATION)
2. Water passes from xylem
vessels in the stem to leaf cells
by osmosis.
3. This ‘pulls’ the water up
through the xylem to replace
that being lost.
4. Water enters the xylem
vessels in the stem from root
tissue to replace the water that
has moved upwards.
Water movement through the plant
1. Water evaporates from the
internal leaf cells through the
stomata (TRANSPIRATION)
2. Water passes from xylem
vessels in the stem to leaf cells
by osmosis.
3. This ‘pulls’ the water up
through the xylem to replace
that being lost.
4. Water enters the xylem
vessels in the stem from root
tissue to replace the water that
has moved upwards.
5. Water enters the root hair
cells by osmosis to replace water
which has entered the xylem.
Water movement through the plant
1. Water evaporates from the
internal leaf cells through the
stomata (TRANSPIRATION)
2. Water passes from xylem
vessels in the stem to leaf cells
by osmosis.
3. This ‘pulls’ the water up
through the xylem to replace
that being lost.
4. Water enters the xylem
vessels in the stem from root
tissue to replace the water that
has moved upwards.
5. Water enters the root hair
cells by osmosis to replace water
which has entered the xylem.
Evaporation of
water from the leaf
results in water
being drawn through
the plants from the
roots = the
TRANSPIRATION
STREAM
Water loss from the leaf
Stoma
Water loss from the leaf
H2O
H2O
H2O
Water evaporates
from the stomata ( =
TRANSPIRATION)
Water loss from the leaf
H2O
H2O
H2O
The Stomata can open
and close in order to
control the amount of
water lost.
Water loss from the leaf
H2O
H2O
H2O
If the plant loses too
much water then it will
wilt
Water loss from the leaf
H2O
H2O
H2O
If the air around the
leaf is very humid then
less water will be lost.
Water loss from the leaf
H2O
H2O
H2O
On a windy day more
water will be lost from
the leaf surface.
Water loss from the leaf
H2O
H2O
H2O
On a hot day more
water will be lost from
the leaf surface.
Water loss from the leaf
H2O
H2O
H2O
As light intensity
increases, the stomata
open more, so more
water is lost.
Sucrose and amino acid movement
through the plant
Sucrose and amino
acids are made in
the leaves. They
are transported to
all parts of the
plant in phloem
tubes.
Sucrose and amino acid movement
through the plant
Sucrose and amino
acids are made in
the leaves. They
are transported to
all parts of the
plant in phloem
tubes.
Sucrose and amino acid movement
through the plant
Sucrose and amino
acids are made in
the leaves. They
are transported to
all parts of the
plant in phloem
tubes.
Sucrose and amino acid movement
through the plant
Sucrose and amino
acids are made in
the leaves. They
are transported to
all parts of the
plant in phloem
tubes.
The cross walls do not
completely break
down, but instead
from sieve plates.
Sucrose and amino acid movement
through the plant
Sucrose and amino
acids are made in
the leaves. They
are transported to
all parts of the
plant in phloem
tubes.
Phloem tubes are
living, and the
movement of sucrose
and amino acids is
thought to be an
active process.
Content
Lesson 5
h) Transport
h) Transport
2.49 understand why simple, unicellular organisms can
rely on diffusion for movement of substances in and out
of the cell
2.50 understand the need for a transport system in
multicellular organisms
Flowering plants
2.51 describe the role of phloem in transporting
sucrose and amino acids between the leaves and
other parts of the plant
2.52 describe the role of xylem in transporting water
and mineral salts from the roots to other parts of the
plant
2.53 explain how water is absorbed by root hair cells
2.54 understand that transpiration is the evaporation of
water from the surface of a plant
2.55 explain how the rate of transpiration is affected
by changes in humidity,wind speed, temperature and
light intensity
2.56 describe experiments to investigate the role of
environmental factors in determining the rate of
transpiration from a leafy shoot
Content
Lesson 5
h) Transport
h) Transport
Humans
2.57 describe the composition of the blood: red blood cells, white
blood cells, platelets and plasma
2.58 understand the role of plasma in the transport of carbon
dioxide, digested food, urea, hormones and heat energy
2.59 explain how adaptations of red blood cells, including shape,
structure and the presence of haemoglobin, make them suitable for
the transport of oxygen
2.60 describe how the immune system responds to disease using
white blood cells, illustrated by phagocytes ingesting pathogens and
lymphocytes releasing antibodies specific to the pathogen
2.61 understand that vaccination results in the manufacture of
memory cells, which enable future antibody production to the
pathogen to occur sooner, faster and in greater quantity
2.62 understand that platelets are involved in blood clotting,
which prevents blood loss and the entry of micro-organisms
2.63 describe the structure of the heart and how it functions
2.64 explain how the heart rate changes during exercise and under
the influence of adrenaline
2.65 describe the structure of arteries, veins and capillaries and
understand their roles
2.66 understand the general structure of the circulation system to
include the blood vessels to and from the heart, the lungs, the liver
and the kidneys.
Transport in Humans
Transport in Humans
Transport in Humans
PLASMA –
Straw coloured liquid.
• transports CO2 from
the tissues to the lungs.
• transports soluble
products of digestion
from small intestine to
the organs and tissues
• transports other
wastes, such as urea,
from the liver to the
kidneys.
• transports hormones
around the body
• carries heat away from
organs and tissues
Transport in Humans
PLASMA –
Straw coloured liquid.
• transports CO2 from
the tissues to the lungs.
• transports soluble
products of digestion
from small intestine to
the organs and tissues
• transports other
wastes, such as urea,
from the liver to the
kidneys.
• transports hormones
around the body
• carries heat away from
organs and tissues
RED BLOOD CELLS (RBCs) –
• transport oxygen from the
lungs to organs and tissues
• contains haemoglobin, a
red pigment
• haemoglobin combines with
oxygen to form
oxyhaemoglobin
• biconcave in shape
• no nucleus
• Large surface area
Transport in Humans
PLASMA –
Straw coloured liquid.
• transports CO2 from
the tissues to the lungs.
• transports soluble
products of digestion
from small intestine to
the organs and tissues
• transports other
wastes, such as urea,
from the liver to the
kidneys.
• transports hormones
around the body
• carries heat away from
organs and tissues
WHITE BLOOD CELLS –
• two main forms,
granulocytes and
agranulocytes.
• granulocytes have a lobed
nucleus and engulf microbes
• agranulocytes have a
rounded nucleus and
produce antibodies to
attack microbes
Transport in Humans
PLASMA –
Straw coloured liquid.
• transports CO2 from
the tissues to the lungs.
• transports soluble
products of digestion
from small intestine to
the organs and tissues
• transports other
wastes, such as urea,
from the liver to the
kidneys.
• transports hormones
around the body
• carries heat away from
organs and tissues
PLATELETS –
Fragments of cells, used
in the blood clotting
process to close wounds.
White cells and immunity
White cells and immunity
Micro-organisms
White blood
cell
White cells and immunity
The white blood cell
begins to surround
the micro-organisms
White cells and immunity
The micro-organisms
are ingested by the
white blood cell and
are destroyed.
White cells and immunity
The agranulocytes produce
antitoxins which neutralise
harmful toxins (poisons)
produced by microorganisms.
White cells and immunity
Micro-organisms that invade our bodies are
called pathogens. Once inside the body these
pathogens (eg. viruses) reproduce inside cells and
damage them, and produce toxins. Cell damage
and toxins cause the symptoms of infectious
diseases.
White cells and immunity
Micro-organisms that invade our bodies are
called pathogens. Once inside the body these
pathogens (eg. viruses) reproduce inside cells and
damage them, and produce toxins. Cell damage
and toxins cause the symptoms of infectious
diseases.
Pathogens contain specific chemicals called
antigens that are detected by white blood cells.
The white blood cells produce antibodies which
latch onto the antigens and destroy the
pathogens.
White cells and immunity
ANTIGEN
WHITE BLOOD
CELL
White cells and immunity
Antibodies produced by
the white blood cell
White cells and immunity
Antibodies attach to the
antigens, causing them to
clump together, and they
are then destroyed.
White cells and immunity
It can take a little time for
the antibodies to be
produced, so we may feel ill
for a time.
White cells and immunity
The production of
antibodies is much faster
if we have already had the
infectious disease. The
white blood cells ‘recognise’
the antigen, respond
rapidly and give us natural
immunity.
Artificial immunity
We can acquire immunity to a particular
disease by being vaccinated.
Artificial immunity
We can acquire immunity to a particular
disease by being vaccinated.
• A weakened or dead antigen
Step 1 is injected into a person.
Artificial immunity
We can acquire immunity to a particular
disease by being vaccinated.
• A weakened or dead antigen is
Step 1 injected into a person.
• The body produces antibodies
Step 2 to fight the antigen.
Artificial immunity
We can acquire immunity to a particular
disease by being vaccinated.
• A weakened or dead antigen is
Step 1 injected into a person.
• The body produces antibodies
Step 2 to fight the antigen.
Step 3
• The body has now acquired immunity to this antigen as
the white blood cells will now recognise the antigen and
respond rapidly with the production of antibodies
Our circulatory system
Our circulatory system
LUNGS
HEART
BODY
Our circulatory system
LUNGS
HEART
BODY
Our circulatory system
LUNGS
Deoxygenated
blood
HEART
BODY
Oxygenated
blood
Our circulatory system
Pulmonary
artery
LUNGS
Pulmonary
vein
HEART
Vena cava
Aorta
BODY
The Heart
The Heart
Right
Left
The Heart
The Heart
Blood to the
lungs
(pulmonary
artery)
Blood from the
body (Vena
cava)
Right atrium
Semi-lunar
valve
Tricuspid valve
Right ventricle
The Heart
Blood to the
lungs
(pulmonary
artery)
Blood from the
lungs
(pulmonary
vein)
Blood from the
body (Vena
cava)
Blood to the
body (Aorta)
Right atrium
Left atrium
Semi-lunar
valve
Semi-lunar
valve
Tricuspid valve
Bicuspid valve
Right ventricle
Left ventricle
The Heart
From
body
From
lungs
Ventricular diastole
(relaxation)
The Heart
When the
ventricular
muscle relaxes,
blood flows into
the left and right
atria, through
veins, from the
lungs (left) and
from the body
(right)
From
body
From
lungs
Ventricular diastole
(relaxation)
The Heart
When the
ventricular
muscle relaxes,
blood flows into
the left and right
atria, through
veins, from the
lungs (left) and
from the body
(right)
From
body
From
lungs
Ventricular diastole
(relaxation)
The right and
left atria then
contract, forcing
open the bicuspid
and tricuspid
valves, and
squeezing blood
into the
ventricles.
The Heart
To the
lungs
To the
body
Ventricular systole
(contraction)
The Heart
To the
lungs
When the
ventricular
muscle contracts
blood is forced
through the semi
– lunar valves into
the arteries,
taking blood to
the lungs and
body
To the
body
Ventricular systole
(contraction)
The Heart
To the
lungs
When the
ventricular
muscle contracts
blood is forced
through the semi
– lunar valves into
the arteries,
taking blood to
the lungs and
body
To the
body
Ventricular systole
(contraction)
The valves
prevent the blood
from flowing in
the wrong
direction. The
cardiac cycle is a
repeating
sequence of
contraction and
relaxation.
Heart rate and exercise
As we exercise, our
heart rate increases.
The more intense the
level of exercise, the
faster our heart
beats.
Heart rate and exercise
As we exercise, our
heart rate increases.
The more intense the
level of exercise, the
faster our heart
beats.
The faster our heart beats, the more oxygen can
be transported to our muscles, and waste
products can also be removed more quickly.
Heart rate and adrenaline
Adrenaline is a hormone secreted by our adrenal glands.
The hormone is secreted when the body anticipates
strenuous exercise, or when we are in a stressful situation.
Adrenaline is carried in the blood and stimulates the heart
to beat faster. More oxygen is therefore pumped to the
muscles.
Heart rate and adrenaline
Adrenaline is a hormone secreted by our adrenal glands.
The hormone is secreted when the body anticipates
strenuous exercise, or when we are in a stressful situation.
Adrenaline is carried in the blood and stimulates the heart
to beat faster. More oxygen is therefore pumped to the
muscles.
Adrenaline is known as the
‘fight or flight’ hormone and
prepares the body by
increasing the oxygen supply,
energy levels, and raising blood
pressure.
The Blood Vessels
The Blood Vessels
ARTERIES
Very thick elastic and
muscular layers which
enable the artery to cope
with the high blood pressure
Small LUMEN (space
through which the blood
passes)
Other features: no valves
needed (high blood
pressure). Carry blood away
from the heart (all
oxygenated, except the
Pulmonary Artery).
Substances cannot pass
from the blood through the
artery walls.
The Blood Vessels
VEINS
Valve
Much thinner elastic and
muscular layers (blood is
carried at much lower
pressure)
Large LUMEN (compared to
the thickness of the walls)
Other features: valves
needed (low blood pressure).
Carry blood towards the
heart (all de-oxygenated,
except the Pulmonary Vein).
Substances cannot pass
from the blood through the
veins’ walls.
The Blood Vessels
CAPILLARIES
Narrow, very thin-walled
vessels, just one cell thick
Microscopic, just enough
room for blood cells to pass
through.
Connect arteries to veins
Exchange of substances
(oxygen, glucose, waste)
between the blood and the
surrounding tissues takes
place here.
The Blood Vessels
Capillary network in a muscle
cell
Artery rich
in oxygen and
food
Arteries branch into
tiny one cell thick
capillaries which pass
close to each cell
before re-uniting to
form a vein.
Vein rich in
carbon
dioxide and
waste
Glucose
Deoxygenated red
blood cells
Blood capillary
Energy
Glucose
+ Oxygen

Carbon dioxide + Water
Muscle cell
Glucose and oxygen
diffuse from the
blood into the muscle
cell
Energy is used
for muscle
contraction
Carbon dioxide and
water diffuse from
the muscle cell into
the blood
Content
Lesson 5
h) Transport
h) Transport
Humans
2.57 describe the composition of the blood: red blood cells, white
blood cells, platelets and plasma
2.58 understand the role of plasma in the transport of carbon
dioxide, digested food, urea, hormones and heat energy
2.59 explain how adaptations of red blood cells, including shape,
structure and the presence of haemoglobin, make them suitable for
the transport of oxygen
2.60 describe how the immune system responds to disease using
white blood cells, illustrated by phagocytes ingesting pathogens and
lymphocytes releasing antibodies specific to the pathogen
2.61 understand that vaccination results in the manufacture of
memory cells, which enable future antibody production to the
pathogen to occur sooner, faster and in greater quantity
2.62 understand that platelets are involved in blood clotting,
which prevents blood loss and the entry of micro-organisms
2.63 describe the structure of the heart and how it functions
2.64 explain how the heart rate changes during exercise and under
the influence of adrenaline
2.65 describe the structure of arteries, veins and capillaries and
understand their roles
2.66 understand the general structure of the circulation system to
include the blood vessels to and from the heart, the lungs, the liver
and the kidneys.
End of Section 2 Lesson 5
In this lesson we have covered:
Transport in flowering plants
Transport in humans