Transcript Unit 2 – Biology – Organisation PowerPoint

Unit 2 - organisation
UNIT 2 - cell organisation - information…
A cell is the basic building block of all
multicellular living organisms. Multicellular
means made of many cells.
Cells are grouped into tissues…..
A tissue is a group of cells with similar structure
and function. Groups of tissues make up organs.
Examples of tissues found in animals include:
■ muscular tissue, which can contract to bring
about movement.
■ glandular tissue, which can produce substances
such as enzymes, acid and hormones.
■ epithelial tissue, which covers some parts of
the body(e.g. skin)
Plant organs
Plant organs include stems, roots and leaves.
Plant Tissues
Examples of plant tissues include:
1.
2.
3.
4.
Epidermal tissues, which cover the plant
Mesophyll, which carries out photosynthesis
Xylem carries water and minerals up the stem from the roots
to the leaves.
Phloem carries sugars down from the leaves where they are
made to the rest of the plant.
Organs are made of groups of tissues. One
organ may contain several tissues.
The stomach is an organ that contains:
■ muscular tissue, to churn the contents.
■ glandular tissue, to produce digestive juices
(acid and enzymes)
■ epithelial tissue, to cover the outside and the
inside of the stomach.
Organ systems are groups of organs that
perform a particular function. The digestive
system is one example of a system in which
humans and other mammals break down and
absorb food into their bloodstream.
A plant organ….roots
Roots absorb water and minerals
into a plant.
They also anchor the plant into the
ground.
Roots have lots of root hair cells.
Root hair cells increase the surface
area of the roots so there is a large
surface for the roots to absorb
enough water and minerals.
Root hair cells also have thin walls
to allow easy passage of water and
minerals into the plant.
Unit 2 Organisational hierarchy – Tissues, organs and organ systems
Tissue
Function
Glandular
Secretes
substance
s e.g. acid
Epithelial
Covers
surfaces
Epidermal
Covers
surfaces
Mesophyll
In the leaf
Xylem
Transport
s water
and
minerals
Phloem
Transport
s sugars
Animal/
Plant
What is a cell?
What are the main organs of a plant?
Name an cell in humans.
What is a tissue?
Name an tissue in humans.
What is an organ system?
What is an organ?
The digestive system’s function is
Name an organ in humans.
Label the stomach, small intestine, large
intestine,, oesophagus, and mouth.
What is an organ system?
Name an organ system in humans.
Cells are the basic building _______ of all
living organisms.
A __________ is a group of cells with a
similar structure and function.
_____________ are groups of tissues
performing specific functions.
Organs are __________ into organ systems,
which work together to form organisms.
Missing words: Organs, organised, tissue,
blocks
cells
--------------------------
--------------------
Gall
bladder
pancreas
Unit 2 - Human digestive system - information
1. Digestion in the mouth
Food is chewed (physical digestion)
to create a larger surface area for
the action of enzymes.
Saliva is released which contains
amylase.
Saliva has a pH of 7.
Amylase digests starch into smaller
sugars (glucose).
Further chewing enables
swallowing.
The food enters the oesophagus.
Digestive system help sheet.
•
Some enzymes work outside the body cells.
•
These are called extracellular enzymes.
•
They catalyse the breakdown of large molecules into smaller soluble
molecules.
•
Digestion is the process where food is broken down into small soluble
products that the body can absorb through the small intestine wall
into the bloodstream.
•
The products of digestion are used to build new carbohydrates, lipids
and proteins. Some glucose is used in respiration.
2. Digestion in the stomach
Food enters the stomach from the
oesophagus.
The walls of our stomach produce juice.
This juice contains:
A protease enzyme (called pepsin).
This digests proteins into amino acids.
Hydrochloric acid – this kills bacteria in our food. It
creates pH 2-3.
Mucus – this protects the wall of our stomach from acid
and pepsin.
The wall of our stomach is muscular, and churns our food
(physical digestion).
The food remains in our stomach for a few hours. The
proteins are digested into amino acids.
Food leaves our stomach in small squirts into the small
intestine.
3. Digestion and absorption in the small intestine
The small intestine has 2 main jobs:
To complete the digestion of the food
To absorb the soluble products of digestion into the blood.
Digestion in the small intestine
3 juices are released:
1. Bile
Produced by the liver.
Stored in the gall bladder.
Released into the small intestine.
2 main things in bile:
It is Alkali to neutralise the stomach acid and create a pH of 8
Bile salts emulsify fats (convert large fat droplets to small fat
droplets) – for a large surface area for the enzymes to act on. Both
increase the rate of fat breakdown by lipase. Emulsifying fats is a
type of physical digestion.
There are no enzymes in bile.
2. Pancreatic juice and
3. Intestinal juice
Both are released into the small intestine.
Both contain 3 main enzymes:
Amylase to complete the digestion of starch into sugars.
Protease to complete the digestion of proteins into amino acids.
Lipase to break down fats into fatty acids and glycerol.
Unit 2 – Human
Digestive system.
Bile is made in the _______
and stored in the
__________. It is _________
to neutralise hydrochloric acid
from the stomach. It also
_________ fat to form
_______ droplets which
___________the surface area.
The alkaline conditions and
large surface area increase
the rate of ______ breakdown
by _________.
Part
CLUES TO HELP
Carbohydrases break down carbohydrates to simple
sugars.
Amylase is a carbohydrase which breaks down starch.
Proteases break down proteins to amino acids.
Lipases break down lipids (fats) to glycerol and fatty
acids.
To help
with the
table
below
Digestive enzymes convert food into
_________ soluble molecules that can
be absorbed into the ______________.
The products of digestion are used to
_________ new carbohydrates, lipids
and proteins. Some glucose is used in
R____________.
Salivary amylase
8, bile
Chewing
Carbohydrates
(starch)
Protein
Glucose
2-3,
hydrochloric acid
7, saliva
Amino acids
Emulsifying
fats
Churning food
Protease
Fats
Proteins
Carbohydrates
Lipase
Protease
Amylase
Fatty acids and
glycerol
Glucose
Amino acids
Fatty acids and
glycerol
Glucose
Amino acids
Fats
Proteins
Carbohydrates
Lipase
Protease
Amylase
Physical Enzymes made
digestion
Food digested
Products of
digestion
pH, and
substance that
creates the pH
Mouth
Stomach
Pancreas
X
Gall bladder
X
Small
intestine
X
X
X
X
X
Unit 2 – Enzymes - information
Enzymes structure and function
•
Enzymes are biological catalysts.
•
Catalysts increase the rate of chemical reactions.
•
Enzymes are protein molecules made up of long chains
of amino acids.
•
These long chains are folded to produce a special shape
which enables other molecules to fit into the enzyme.
•
This shape is vital for the enzymes function.
•
Normally only one type of molecule (the substrate) will
fit into the enzyme.
•
The active site is the part of the enzyme which the
substrate fits into, because it is a certain shape
enzymes only fit one substrate (they are specific).
This is
how
digestive
enzymes
work
This is how
molecules are
built up in the
body. E.g.
muscle tissue
The effect of pH on enzymes
pH can also affect the shape of the active site.
It does this by affecting the forces that hold the
enzyme molecule together.
A change in pH can denature the enzyme.
Different enzymes work best at different pH
values (they have different optimum pHs)
Eg. Stomach enzymes work best in acidic
conditions.
Mouth enzymes work best in neutral conditions.
Effect of temperature
on enzymes
Like most chemical
reactions, the rate of
enzyme-controlled
reactions increases as
the temperature
increases.
The enzyme and
substrates move around
faster so they collide
more often.
The temperature when
the enzyme is working
fastest is called the
optimum.
This is true up to
approximately 40˚C,
higher than this and the
structure of the enzyme
changes.
As a result, the active
site becomes a different
shape and the substrate
no longer fits.
It is then described as
denatured.
Unit 2 – Enzymes
Proteins, Catalysts &
Enzymes
Factors Affecting Enzyme
Action.
What type of acid is produced in
the stomach?
What are protein molecules made of?
Why is the stomach acidic?
What are enzymes made from?
Enzymes are biological ____________ that
__________ up chemical reactions in living organisms
The ___________ in a reaction can be held in the
active site and either be connected to another molecule
or be broken down.
Write an equation to show how enzymes break
molecules down.
Speeding up Digestion
The warmer the temperature the faster
enzymes will work until ______ oC. At
temperatures higher than this the enzyme
stops working, the enzyme becomes
________________.
Each enzyme works best at a particular
_____ value, e.g. enzymes in the mouth
have an o_________ pH of ______.
Enzymes in the stomach have an
o_________ pH of ______.
Why wont amylase from the
mouth work when it reaches the
stomach?
Specificity
Why do enzymes only catalyse a
specific reaction?
Explain why an enzyme can’t catalyse a
reaction if it is denatured?
Mode of action – explain using the
lock and key hypothesis how
enzymes work.
Write an equation to show how enzymes build
molecules up.
What does optimum temperature mean?
What does optimum pH mean?
KEY WORDS:
Denatured, Bile, Enzymes, Active site,
Substrates , amylase
Unit 2 – the lungs - information
This is a diagram of the lungs
The main wind pipe is called the
trachea. It is strengthened by
rings of cartilage, these rings
prevent the trachea from
collapsing. The trachea splits into
two branches called bronchi, each
one delivers air to each lung. The
bronchi split into smaller tubes
called bronchioles. Bronchioles end
in air sacs called alveoli. Alveoli is
the location of gaseous exchange.
Gaseous exchange involves the
diffusion of oxygen into the blood
and carbon dioxide out of the
blood. Thee oxygen is delivered to
every cell in the body, where it is
needed for respiration. The waste
gas of respiration is carbon dioxide,
this is transported back to the
lungs. Carbon dioxide then diffuses
into the alveolus and is breathed
out.
Blood becomes
oxygenated in
the lungs.
Deoxygenated
blood is blood
that has no
oxygen in it.
Oxygenated
blood is blood
that has oxygen
in it.
Gaseous
exchange is by
diffusion.
Label the alveolus
Labels: red blood cell, capillary wall, alveolus wall,
alveolus air space, oxygen entering the blood, carbon
dioxide leaving the blood, oxygenated blood,
deoxygenated blood.
Deoxygenated
blood
Capillary wall
Alveolus wall
Oxygen diffusing
into the blood
Direction of
blood flow
The following points ensure
gaseous exchange is efficient
Alveolus air space
carbon dioxide
diffusing out of
the blood.
Oxygenated
blood
Red blood cell
Alveolus wall
Characteristic
Reason
Large surface area:
volume ratio
Increases rate of
exchange
Epithelia is 1 cell
thic
Short diffusion
pathway
Constant movement
of air and blood
Maintains diffusion
gradient
Moist
Gases dissolve to allow
diffusion
How the alveoli are adapted for gaseous exchange…
they have a
• large surface area.
• moist surface to allow oxygen to dissolve.
• thin lining to allow easy diffusion of gases.
• Lots of blood capillaries surrounding them for easy gas
exchange.
Unit 2 – the lungs
Label the alveolus
Labels: red blood cell, capillary wall, alveolus wall,
alveolus air space, oxygen entering the blood, carbon
dioxide leaving the blood, oxygenated blood,
deoxygenated blood.
Label the diagram of the lungs:
Labels
•Trachea
•Alveoli
•Bronchi
•Bronchioles
1
3
2
6
Direction of
blood flow
8
5
9
Join up the left side words with their correct meaning or explanation.
alveolus
There are thousands of these tiny air-sacs in the
lungs
bronchi
Bronchi divide into two smaller and smaller tubes.
Bronchioles
The main breathing tube, it is strengthened by
cartilage.
trachea
oxygen
carbon dioxide
Ribs
A gas that we need for respiration.
Bones that protect the lungs
Respiration produces this waste gas that moves out
of the blood.
The tube between the trachea and a bronchiole
4
7
•Circle the correct word out of each choice. The alveoli
have....
•A small/large surface area.
•A moist/dry surface to allow oxygen to dissolve.
•A thin/thick lining to allow easy diffusion of gases.
•A few/many blood capillaries surrounding them for easy
gas exchange.
UNIT 2 – THE HEART
Pulmonary
artery
aorta
Pulmonary vein
Vena
cava
The heart - function - an organ that pumps blood around the body in a double circulatory
system.
Double circulatory system It is a double circulatory system. It comprises two separate circuits
and blood passes through the heart twice. Tthe right ventricle pumps blood to the lungs where
gas exchange takes place and the left ventricle pumps blood around the rest of the body.
The heart is made of cardiac muscle.
The natural resting heart rate is controlled by a group of cells located in the right atrium that
act as a pacemaker. Artificial pacemakers are electrical devices used to correct irregularities in
the heart rate.
Left atrium
The heart and cholesterol
valves
•Cholesterol is a substance found in the blood. It is made in the liver and is needed for
healthy cell membranes.
Left atrium
•There are two types of cholesterol – good and bad cholesterol
Left ventricle
Right ventricle
1. Low-density lipoproteins (LDLs) are bad - they carry cholesterol from your liver to
your artery walls.
2. High-density lipoproteins (HDLs) are good, they reduce the cholesterol in your blood
and prevent build up of fatty tissues in the artery wallls.
y
Cardiac muscle wall
Deoxygenated blood is pumped to the lungs via the
pulmonary artery. The blood picks up oxygen (becomes
oxygenated) and is returned to the heart via the
pulmonary vein. The oxygenated blood is then pumped to
the body via the aorta. Once the oxygen has been
delivered to the tissues the blood becomes deoxygenated
again and returns to the heart via the vena cava.
The right side of the heart always carries deoxygenated
blood and the left side always carries oxygenated blood.
The heart muscle requires a large amount of oxygen and
glucose. This is supplied by the coronary artery. If this
becomes blocked a heart attack results – this could lead
to a cardiac arrest.
•Saturated fats increase bad cholesterol. Mono- and polyunsaturated fats reduce bad
cholesterol levels.
•If someone has a high level of bad cholesterol fat builds up in the artery walls,
reducing the diameter of the artery. When this happens in the coronary arteries
leading to the heart muscle, the blood flow is reduced. This can cause pain and may
lead to blood clots lodging in the artery. This is a heart attack.
The heart has four chambers and is divided into two separate halves.
Each half has an upper chamber - the atrium, and a lower chamber - the ventricle.
•The atria receive blood into the heart.
•The ventricles pump blood out of the heart.
Because the ventricles pump blood out of the heart, they have thicker walls than the atria. The
atria only pump blood into the ventricles.
The left ventricle wall is thicker than the right ventricle because the left ventricle has to pump
blood further (to the body) whereas the right ventricle only has to pump blood to the lungs.
Valves are present - between the atria and ventricles
- in the pulmonary artery and the aorta
Valves are essential to prevent the backflow of blood. If they are damaged the delivery of
oxygenated blood is slowed.
Unit 2 - The Heart
Label the heart
What is meant by a double circulatory system?
Why do humans need a double circulatory system but fish do not?
Why are the ventricle walls thicker than the atria walls?
Why is the left ventricle wall thicker than the right ventricle wall?
What side of the heart carries oxygenated blood?
What vessel provides the heart muscle wall with glucose and oxygen?
What causes a heart attack?
What is cholesterol?
What does bad cholesterol do?
What does good cholesterol do?
What type of fats contains a lot of bad cholesterol?
What types of fat contain good cholesterol?
What do heart valves do?
Where are the hearts natural pacemaker found?
What does the hearts natural pacemaker do?
What do we call blood with oxygen in it?
What do we call blood with no oxygen in it?
UNIT 2 – BLOOD VESSELS
Vein
Large
lumen
and thin
walls
Capillary
Artery
Very small –
penetrate all
tissues. Wall
one cell thick
and permeable.
Small
lumen
and thick
walls
The pulmonary artery carries blood to the lungs to pick
up oxygen, it is the only artery that carries deoxygenated
blood.
The pulmonary vein carries blood away from the lungs
back to the heart., it is the only vein that carries
oxygenated blood.
Veins
Function – to carry blood to the heart at a low
pressure.
Carry blood to the heart
Have thin walls with a larger internal lumen.
Have valves to prevent blood flowing backwards
Arteries
Function – to carry blood away from the heart at a high
pressure.
Have thick muscular walls, that can constrict to keep the blood
pressure high. Have small internal lumen. They have no need
for valves.
Arteries have a tough outer layer and an elastic layer inside they can cope with the pulses of blood. The walls allow a small
amount of stretch to prevent the walls tearing.
Capillaries
Function – to allow exchange of gases ((oxygen and carbon
dioxide), nutrients (glucose and amino acids) and waste
products (urea and carbon dioxide) between the blood and the
tissues. E.g. Oxygen passes through the capillary wall and into
the tissues, carbon dioxide passes from the tissues into the
blood
They carry blood between the arteries and veins.
They are very small – their walls are one cell thick – this allows
them to be permeable. They carry blood at a low pressure.
The capillaries in the lungs are where gas exchange takes place.
Here oxygen passes from the air spaces in the lungs through the
capillary wall into the blood. Carbon dioxide passes from the
blood into the air spaces.
Capillaries are adapted for exchange because they have thin
wall to allow easy exchange and they are narrow so have a
large surface to volume ratio. This means there is more surface
for exchange.
UNIT 2 – BLOOD VESSELS
Fill in the table below
Arteries
Capillaries
Veins
function
Blood direction
Blood pressure
Wall thickness
Which artery carries deoxygenated blood? Explain
why?
Size of internal
diameter (lumen)
Valves present?
Which vein carries oxygenated blood? Explain why?
Is blood usually
oxygenated or
deoxygenated?
Why do arteries need a thick muscle wall and narrow lumen?
Describe the differences in the substances that are exchanged in the tissues and
in the lungs.
Why do veins have valves?
How are capillaries adapted for exchange?
Why do capillaries need permeable walls.
UNIT 2 – THE BLOOD
Blood has four key components:
1. Plasma
The following substances are carried in the plasma:
• Dissolved carbon dioxide: This is the waste gas produced by respiration in cells.
• Dissolved glucose and amino acids: Food molecules for respiration, building and
repairing cells
• Dissolved Urea: Waste product produced by the liver and filtered out of the blood by
kidneys
• Antibodies and antitoxins: Chemicals that protect us from disease and poisons
• Hormones: Chemicals that control some of our body functions – e.g. insulin.
Plasma has a yellowish appearance. It sometimes oozes out of blisters.
3. Platelets
These are not really cells in their own
right. They are fragments of cells.
They protect the body by stopping
bleeding and sealing wounds to prevent
the entry of bacteria.
Their job is to form part of a clot so that
they plug a wound and stop too much
blood being lost. Without that clotting
mechanism you would cut your finger and
bleed to death!
2. White blood cells
An important part of the
immune system. There are
thousands of different types
each with a specific job in
defending the body against
disease.
Some white blood cells 'eat'
invading cells. Others produce
antibodies to destroy harmful
microorganisms.
4. Red blood cells
They carry oxygen for aerobic respiration.
They absorb oxygen in the lungs, pass through
narrow blood vessels, and release oxygen to
respiring cells.
Red blood cells have adaptations that make them
suitable for this:
• Red blood cells contain the oxygen carrying
molecule haemoglobin; this is a special pigment
that gives blood its red colour. Iron is needed in
the production of haemoglobin; if your diet lacks
this mineral you can develop the condition
anaemia.
• Red blood cells do not contain a nucleus, this is
so there is more space in the cell for
haemoglobin.
• They are small and flexible so that they can fit
through narrow capillaries.
• They have a biconcave shape (flattened disc
shape) to maximise their surface area for oxygen
absorption
The biconcave shape provides a large surface area
compared to the volume of the red blood cell,
allowing diffusion to happen efficiently.
When blood picks up oxygen we say that it has
been oxygenated. This happens because
haemoglobin molecules form weak bonds with
oxygen to make a new complex molecule called
oxyhaemoglobin.
UNIT 2 – THE BLOOD
Label the components of the blood
Red blood cells
What is the role of the red blood cell?
List the 4 adaptations that allow red blood cells to carry out its function.
How does the biconcave disc shape help the red blood cell carry out is job?
Why don’t red blood cell live for very long?
What is formed when oxygen combines with the red pigment found in red blood cells?
Match the beginnings t the ends of the sentences below …..
Plasma
1. Name 4 substances that are dissolved in the plasma
Red blood cells contain a substance
which helps it to absorb oxygen.
Their biconcave shape means that the
cell has a large surface area
this creates more room for haemoglobin
inside the cell allowing them to carry
more oxygen.
Red blood cells do not contain a nucleus
them to become distorted as it squeezes
through narrow capillaries and then
restores to its original shape.
called haemoglobin,
which combines with oxygen to form
oxyhaemoglobin.
1. Name 3 things that are suspended in the plasma
What part of the blood fights pathogens that enter the
body?
What is a pathogen?
Red blood cells are small and flexible
this allows
Platelets
What is the role of the platelets?
UNIT 2 – Blood and Treatment of Heart Conditions
The coronary artery is labelled X
In coronary heart disease layers of fatty
material build up inside the coronary
arteries, narrowing them. This reduces
the flow of blood through the coronary
arteries, resulting in a lack of oxygen for
the heart muscle.
If they are narrowed blood clots are
more likely to lodge. If a blood clot
does lodge then a heart attack will
occur.
Treatments for faulty hearts
Stents are used to keep the coronary
arteries open.
Statins are widely used to reduce blood
cholesterol levels which slow down the
rate of fatty material deposit.
In some people heart valves may become
faulty, preventing the valve from opening
fully,
or the heart valve might develop a leak.
Faulty heart valves can be replaced using
biological or mechanical valves.
x
Statins
Statins are a group of medicines that can help
lower rates of low-density lipoprotein (LDL)
cholesterol (so called ‘bad cholesterol’) in the
blood. They do this by reducing the production
of LDL cholesterol inside the liver. The British
Heart Foundation reports than only 1 in every
10,000 people who take statins will experience
a potentially dangerous side effect. Also the
risks of any side effects have to be balanced
against the benefits of preventing serious
conditions such as heart attack and stroke.
It is estimated that statins save 7,000 lives a
year in the UK.
Many people who
take statins
experience no or
very few side
effects. Others do
experience
troublesome but
usually minor side
effects, such as an
upset
stomach, headache
or problems
sleeping (insomnia).
UNIT 2 – Blood and Treatment of Heart Conditions
How could the build up of fatty tissue cause a heart attack?
What is the vessel that is labelled x?
What are statins?
What are the advantages of taking statins?
x
What causes the blockage?
What are the disadvantages of taking statins?
What are the advantages of treating someone with a faulty heart with a
heart transplant?
What are the disadvantages of treating someone with a faulty heart
with a heart transplant?
Describe how a stent could be used to treat this.
1)
2)
Artificial Hearts
Artificial hearts have been used temporarily to
keep people alive while they wait for a heart
transplant. The artificial heart is not living so
needs a power source, early power sources were so
large that the patient had to stay in hospital. New
advances mean that the patient can now use a
portable power supply and can go home.
Advantages
The artificial heart is not rejected by the body
Keeps the patient alive whilst waiting for a
transplant (can be used as a short term mesure)
Can be used to allow the heart to rest as an aid to
recovery.
Disadvantages
Surgery can lead to bleeding and infection.
 Blood does not flow as easily and can led to clots
so blood thinners (such as warfarin) need to be
taken.
Parts of the heart can wear out or stop working.
Need an external power supply
Often people have had to stay in hospital
Huge expense
Replacement valves
The valves in the heart control the direction
of flow of the blood . Disease can cause the
valves to degenerate and stop opening
and closing correctly. This makes the
person very tired and listless. There are
two types of replacement valves:
- Mechanical valve: made from man-made
material such as metal, cloth or ceramic
- Biological valve: made form human or
animal tissue (mostly pigs).
Advantages
The success rate is high, they prolong life
and can expect the new valve to last up to
20 years
Disadvantages
May need to have blood thinners to stop
clotting
There is always a risk of serious
complications with surgery
Stents
Arteries can get blocked, weakened or
narrowed due to coronary heart disease
and can cause heart attacks. A stent can
be placed in the artery to keep the artery
open so blood can flow through it.
Advantages
The success rate is high, they lower the
risk of a heart attack and last for a long
time.
No need for open heart surgery.
Disadvantages
Complications like bleeding, irregular
heartbeat and infection.
Arteries sometimes reclose
Drugs needed to stop blood clotting
List the advantages and disadvantages
of artificial hearts
List the advantages and disadvantages
of inserting stents
List the advantages and disadvantages of
replacement valves
Mechanical valves are made of materials such as titanium and polymers. They last for
a very long time. However with a mechanical valve you have to take medication to
prevent clots from forming and antibiotics to prevent infections setting in.
Biological valves are taken from animals such as pigs or cattle or can be donor valves
from humans. When fitted with a biological valve there is not usually the
requirement to take anti clotting drugs however they are not as durable as
mechanical valves and will need to be replaced after about 15 years.
Compare advantages and disadvantages of artificial and biological valves.
Unit 2 REVISION – Health issues Non-communicable diseases
Types of disease
1. Communicable diseases
These spread from one
person to another or from
an animal to a person via
viruses, bacteria, blood or
bodily fluid. The diseases
tend to be infectious and
contagious
Examples
•
cold
•
Chicken pox
•
Influenza
•
Mumps
•
Malaria
•
Sexually transmitted
infections
2. Non-communicable
diseases
Also known as chronic
diseases and are not passed
from person to person. They
can last many years and
progress slowly.
Examples
•
Heart attacks
•
Strokes
•
Cancers
•
Respiratory diseases
•
Diabetes
•
Epilepsy
Non-communicable diseases are caused by the
interaction of a number of factors
Risk factors increase the chance of an individual
developing a disease
Three types:(a) Aspects of a persons lifestyle (diet, exercise)
(b) Substances in the body (drugs)
(c) Substances in the environment (pollution).
A CAUSAL mechanism has been proven for some risk factors but
not others.
e.g. Carcinogens are cancer causing agents. For example,
excessive exposure of UV radiation has been proven to be the
CAUSE of melanoma (a type of skin cancer)
other proven risk factors
• The effects of poor diet, smoking and lack of exercise on
cardiovascular disease (heart disease).
• Obesity as a risk factor for Type 2 diabetes.
• The effect of excess alcohol on the liver and brain function.
• The effect of smoking on lung disease and lung cancer.
• The effects of smoking and alcohol on unborn babies (causes
foetal alcohol syndrome).
Non-communicable disease is on the
increase, especially in developed countries.
This is putting a strain on health systems.
Different types of disease may interact.
• Defects in the immune system mean
that an individual is more likely to suffer
from infectious diseases.
e.g. HIV is a virus that kills the white
blood cells of the immune system leading
to diseases such as Tuberculosis (lung
disease) - this is the leading cause of
death of people who develop AIDS.
It develops because the immune system is
weakened.
• Viruses living in cells can be the trigger
for cancers.
e.g. Human papilloma virus. This virus
can be transmitted from an infected
person through unprotected sex and will
live inside her cells.
Some strains of the virus living are known
to INCREASE the risk of developing
cervical cancer.
• Immune reactions initially caused by a
pathogen can trigger allergies such as skin
rashes and asthma.
• Severe physical ill health can lead to
depression and other mental illness.
Unit 2 REVISION – Health issues Non-communicable diseases
What causes
communicable diseases ?
What is a risk factor?
Different types of disease may interact.
Which type of disease is linked with risk factors,
communicable or non-communicable?
What disease is HIV linked to?
How are these two diseases linked?
Give some examples of
Communicable diseases .
What are the three types of risk factors? Give an example
of each one?
What disease is human papilloma virus
linked to?
What causes noncommunicable diseases ?
What do we call a risk factor that has been proven to cause a
disease?
Fill in the risk factor or the disease.
How are these two diseases linked?
Risk Factor
Give some examples of
non-communicable
diseases .
Non-Communicable Disease
Alcohol
Type 2 Diabetes
Heart Disease
Smoking
Foetal abnormalities
Ionising radiation
Symptoms of stress such as low
energy, headaches, chest pain,
fast heart beat, insomnia
Points for discussion…
How is this rise in disease currently impacting on
our society?
What will be the cost to human life if this
continues?
What may be the financial implications? How far
may this go?
Unit 2 – Cancer
• Cancer happens when cells begin to divide out of
control
• Mitosis is no longer controlled
• They form tumours that can sometimes be felt as an
unusual lump in the body.
Scientists have identified lifestyle risk factors for
various types of cancer including smoking,
obesity, common viruses and UV exposure. There
are also genetic risk factors for some cancers.
Malignant tumours
Tumours cells that are able to invade the
surrounding tissue and spread into nearby organs
where they can cause serious and, eventually, fatal
damage.
In many malignant tumours, the cells continue to
divide
They may spread into blood vessels
Get carried around the body
May get stuck in a smaller blood vessel in another
part of the body
They may begin to divide and grow again forming a
new tumour
These form secondary tumours
The process is called METASTASIS
.
Benign tumours
The cells stay in the same place and the tumour stops
growing before it gets very large - often because it
simply runs out space to grow.
These are called benign tumours and they are not
normally dangerous.
We all have benign tumours, such as moles and warts.
Unit 2 – Cancer
Design a table to summarise the differences between a
benign and malignant tumour?
Benign
What is the link between mitosis and cancer?
Malignant
List some risk factors and the types of cancer they
increase the chance of.
Draw an annotated diagram to summarise the process
of metastasis and formation of a secondary tumour.
•They may spread into blood vessels and get carried around
the body and they may begin to divide and grow to form a
new secondary tumour
•The cells stay in the same place and do not spread to other
parts of the body.
•The tumour stops growing before it gets very large - often
because it simply runs out space to grow.
•They are not normally dangerous.
•Examples are moles and warts.
•They spread into nearby organs where they can cause
serious and, eventually, fatal damage.
•Tumours cells that are able to invade the surrounding
tissue.
•The cells continue to divide and the tumour doesn’t stop
growing.
Unit 2 – PLANT TISSUES AND THE LEAF
The leaf is a plant organ. The structures of tissues in
the leaf are related to their functions.
Stomata
Stomata are pores, mainly on the underside of the leaf, they allow gases to
enter and leave the plant.
They are surrounded by guard cells whose function is to close the stomata
(usually at night) to prevent too much water loss.
Plants that live in dry environments usually have less stomata.
Water loss is a problem for plants as leaves collectively have a very large
surface area.
Plants that live in dry areas have less stomata.
Part
Stomata
Vein
Spongy Mesophyll
Waxy Cuticle
Upper Epidermis
Meristem tissue is found at the growing tips of shoots and roots.
Meristem tissue will differentiate into different plant cells.
This was discussed in unit 1 – these cells are used to carry out tissue
culture, they are essentially stem cells.
Description
Pores on the underside of the leaf that allow
gases to enter and leave the leaf.
Contains the xylem that transports water to
the leaf.
Layer of cells with air-spaces between them.
The spaces allow easy movement of gases
through the leaf.
Waxy layer on the top of the leaf - this
waterproofs the leaf to stop water
evaporating out of the top surface.
Single layer of flat cells covering the top
surface of the leaf. They are transparent to
let light through.
Palisade Cells
Layer of long cells just under the upper epidermis they
have lots of chloroplasts to carry out photosynthesis.
They are near the top so they can absorb more sunlight.
They have thin walls so they can exchange gases easily.
Guard Cells
Cells that control the closing and opening of
the stomatal pores.
Single layer of flat cells covering the bottom
surface of the leaf.
Lower Epidermis
Unit 2 – PLANT TISSUES AND
THE LEAF
Rearrange the table to match the
parts with the jobs
1. What is the function of stomata?
2. What is the function of the guard cells?
3. When do the guard cells open the stomata?
Past paper question….
6 marks
4. When do the guard cells close the stomata?
5. Where are there more stomata found, the top
or the bottom of the leaf?
6. What would happen if the stomata did not have
guard cells?
7. Some types of plants may have less stomata,
what type of habitat would they be from?
8. What can meristem tissue do? Where is it found?
Answer to past paper question…
• Epidermis covers the top and bottom of the leaf.
• Upper epidermis has no chloroplasts so allows light to reach the
palisade cells.
• Palisade cells have lots of chloroplasts to trap light to carry out
photosynthesis.
• Palisade cells are situated near the top of the leaf for receiving
more light for photosynthesis.
• Phloem transports sugars
• Xylem transports water and minerals
• The waxy cuticle reduces water loss from the surface of the leaf.
• The stomata allow CO2 in and O2 out of the leaf.
• Guard cells can open and close the stomata to control water
loss.
• Spongy mesophyll has lots of air spaces for rapid movement of
gases
Unit 2 – xylem, phloem and meristems
Phloem
Plants have transport systems to move food, water and minerals around.
These systems use continuous tubes called xylem and phloem:
Xylem
Function
Xylem tissue transports water and
mineral ions in the transpiration stream f
rom the roots to the stems and leaves.
Structure of the xylem tissue
Xylem vessels consist of dead cells.
They have a thick, cell wall strengthened with
lignin and a hollow lumen.
The end walls of the cells have disappeared, so a long, open tube is formed.
The walls of the xylem vessel contains holes called pits which water enters
through.
In woody plants (trees!) the xylem makes up the bulk of the wood and the
phloem is found just beneath the bark
Root hair cells
are adapted for the efficient uptake of water by osmosis and
mineral ions by active transport.
Function:
Absorbs minerals and water from soil
Structure:
Thin walls to allow easy entry of water and minerals
Extension of cell – collectively create a large surface area to allow enough
surface area for water and minerals to enter.
Function….
Phloem tissue transports dissolved sugars from the leaves to the
rest of the plant for use or storage. The movement of food
through phloem tissue is called translocation.
Structure…
Phloem is composed of tubes of elongated cells. Cell sap can
move from one phloem cell to the next through the end walls
that form sieve plates.
Unlike the xylem, the phloem tissue is made of columns of living
cells, which contains a cytoplasm but no nucleus, and its
activities are controlled by a companion cell next to it which has
a nucleus.
How is Phloem adapted for its function
1.
Sieve tube where glucose is transported has no nucleus –
there is only strands of cytoplasm so the flow of glucose is
not interrupted.
2.
The end walls have perforated sieve plates along the
length to allow sugars to move across them easily.
3.
Each sieve tube has a companion cells next to it.
The companion cell has a nucleus which allows it to
control the sieve tube.
Unit 2 – xylem, phloem and meristems
Name the two transport vessels
How is the root hair cell adapted to increase absorption?
What substances are absorbed by the roots?
1)-__________
How is xylem adapted to transport water and minerals up
the stem?
How is phloem adapted to transport sugars from the leaves?
2) -___________
•
What does vessel 1 transport?
•
Where does vessel 1 transport substances?
•
What causes the movement of water up the plant?
•
What does vessel 2 transport?
•
Where does vessel 2 transport substances?
•
What is the name for the movement of water up the vessel?
•
What is the name for the movement of sugars through vessels?
Unit 2 – Transpiration
•Transpiration is the loss of water vapour through the stomata on
the under surface of the leaves of a plant.
•It is the evaporation of water from the cells in leaves followed by
diffusion of the water vapour out of the stomata.
•As water evaporates from the surface of the leaves more water is
pulled up through the xylem to take its place.
•This is how water gets pulled up from the roots – it is called the
transpiration stream.
Precautions to use when you use a potometer…
• Cut stem under water
• Insert stem into apparatus under water.
• Make sure all joints are sealed.
A Potometer actually measures the rate of water uptake.
This is quite accurate because any water that is lost
through the leaves is replaced by water entering the plant.
The more water lost the more water enters.
Remember diffusion happens faster if the difference in concentration is larger.
Factors which affect the rate of transpiration are:
• temperature - If it is hotter the water vapour particles have more kinetic energy and will diffuse faster.
• humidity - If the air is dry the difference in concentration is bigger and diffusion is faster.
• air flow - If it is windy the water vapour that evaporates out of the leaf is moved away. The difference in concentration stays large
and diffusion is faster.
• light intensity. - Stomata are open during the day and closed during the night. Water cannot escape when the stomata are closed.
Unit 2 – Transpiration
•Describe transpiration.
•What causes water to move up the xylem?
What is the name for this piece of equipment:
How can it be used to measure transpiration?
What precautions should you use when setting this
equipment up?
List the 4 factors that affect the rate of transpiration and explain why they affect it.