Immunity

Natural Artificial
Active Active
This involves a person being exposed to This involves the injection of antigens into a person
a live pathogen (containing antigens), via a vaccine. Now you may wonder why a
developing a disease and then becoming doctor/nurse would want to inject the bad stuff into
immune to it. B-cells (a type of people. The vaccine is actually made up of a
lymphocyte) in the body produce weakened form of a pathogen. Its purpose is to help
antibodies that help to fight against the create an immune response by causing the person’s
invading microbes. This is a long-lasting body to produce antibodies to fight off these
response. This is long lasting. antigens. Memory cells in the person’s body are
then stimulated to remember the pathogen so that if
the pathogen were to attack the body again, they
would quickly be attacked and
destroyed, before symptoms of the disease could
even develop. These memory cells last for a long
time. This is long lasting.
Passive Passive
This involves a pregnant mother passing This involves the injection of antibodies harvested
antibodies (the good stuff) to her unborn from an animal or lab into a person who has an
baby through the placenta or to her born infection or disease. Since the antibodies have
baby through breastmilk. These already been made, they will fight off the antigens
antibodies help defend against antigens and the person will recover quickly. This response
(the bad stuff) that may try to attack the lasts for a short time.
baby’s immune system, however; they This is short lasting.
do not last very long.
This is short lasting.

Immunity – the state of being unaffected by a pathogen or disease.

Vaccination - the use of a vaccine to produce immunity against a pathogen or disease.
Antibodies – substances produced by the immune system (body) for fighting or killing.
antigens. Antibodies are therefore the good substances. Antibodies are produced exactly
according to the organism invading the body. They recognize the invader with the help of
proteins on its surface called antigens.
Antigens – foreign substances not produced by the body, which cause the body harm. The
presence of antigens results in the production of antibodies i.e., an immune response is created.
Antigens are therefore the bad substances.
Active – readily engaging by producing substances.
Passive – passed on from one source to another.
Natural – innate/born with or found within our bodies.
Artificial – given or acquired from outside sources.
 Transport in Plants
Transpiration
- The evaporation of water from the surface of the leaves of plants (stomata). It is due to the
concentration gradient between the plants and the atmosphere. Transpiration produces a tension
or ‘pull’ on the water in the xylem vessels to leaves.
Adversely, translocation is the process by which manufactured food: sugars (mainly sucrose),
amino acids, and other nutrients are transported through the plant.

Factors which influence the rate of transpiration:

- Light intensity
- Temperature
- Humidity
- Wind velocity
- Water level in soil
They all increase transpiration rate except for humidity. This is because all moisture in the air
increases (humidity) it is harder to maintain the leaf’s concentration gradient
Two plant organs involved:

Xylem transport water and minerals from the roots to the stem and leaves

Phloem vessels transport food materials (mainly sucrose and amino acids) made by the plant
from photosynthesizing leaves to non-photosynthesizing regions in the roots and stem.

Together they make up the vascular bundle.

The characteristics can be outlined by their functions above.
Xylem have thick walls with lignin to withstand the flow of water up the stem. It is hollow and
has NO living cells and no end walls for maximum water transportation. It only flows in one
direction; up as we recall water has no need to go down the plant because water is lost through
transpiration.
Phloem walls have no lignin, water and food (sugar: sucrose) is carried both up and down the
plant through sieve tube elements which consist of sieve plates. The purpose is to get the
necessary nutrients to all parts of the plant especially the meristems. Unlike the xylem, phloem is
living tissue because it has a companion cell.
Three main methods:
1. Root pressure.
2. Capillarity: cohesion and adhesion.
3. Transpiration pull.
Root pressure
The water diffuses easily (via osmosis) into the root hairs because the high concentration of
dissolved materials in the cells of the plant's cytoplasm - concentration gradient. The absorption
of water into the plant’s roots creates pressure in the root xylem. Water therefore moves across
the root hair membrane and through the cells themselves, via channels that connect their
contents. Once in the xylem, the water can be carried to the areas of low pressure in the leaves.

Osmosis therefore causes water to pass into the root hair cells, through the root cortex, into the
xylem vessels and then to the leaves.

Capillarity is movement via two methods.

Cohesion - the attraction of water molecules to each other (stick together) think about glue
sticking to paper.
Adhesion - the attraction of water molecules to walls of the xylem vessels. Think about how glue
doesn’t stick to the bottle.

Water molecules, in sticking together and to the walls of the xylem, rise up these narrow vessels
against the force of gravity.

Transpiration pull occurs because loss of water via evaporation in the leaves creates a tension
that pulls water upwards. 
As individual cells absorb and release water, they pass it along to neighboring cells. Water enters
and leaves cells through osmosis - passive movement of water across a membrane. 
Transpiration pull is the strongest force that pulls and transports water to the leaves of all plants.

There is a continuous loss of water caused by transpiration in leaves, a vacuum is therefore

created which effectively pulls the water up the tubes of the xylem towards the leaves where it is
lost. Leaves depend on this efficient delivery system for their supply of water. If the transpired
water is not replaced by water transported up from the roots, the leaves will wilt and the plants
will eventually die.

Better explained here: https://www.youtube.com/watch?v=d60lqIfGeQw

 Transport in Animals
Circulation
Why do animals need a transport system?
- Oxygen can reach cells for respiration
- Carbon dioxide can leave cells after respiration
- To get nutrients to cells that need it
- To get rid of heat and other waste products
- To move hormones to their respective sites
- To get white blood cells to their target sites

N.B., Unicellular organisms like amoeba have large surface area to volume ratios and so, simple
diffusion fulfills the bodily needs. Adversely, multicellular organisms like humans have small
surface area to volume ratio so we need more complex processes. The LARGER an organism is,
the smaller its surface area to volume ratio.
In animals, blood is the transporting fluid of the circulatory system while blood vessels; arteries,
veins & capillaries, are the transporting vessels/media. Capillaries; examples arterioles,
venules.

The heart
It is the muscular organ at the centre of your circulatory system, responsible for pumping
oxygenated blood around your body as your heart beats. The heart is located at the left side of
your chest cavity - known as the mediastinum. The blood transported sends oxygen and nutrients
to all parts of your body and carries away unwanted carbon dioxide and waste products.
There are four chambers; the upper chambers called atria (left and right atrium) and the lower
chambers called ventricles (left and right ventricles).

 The right side of the heart receives deoxygenated blood from the body and pumps it to
the lungs (the pulmonary circulation)
 The left side of the heart receives oxygenated blood from the lungs and pumps it to the
body (the systemic circulation)

The septum divides the left and right sides. *think about your nose, the septum divides the
nostrils.
 Note well if a drawing or question is encountered, your left side is your right and right is
your left. Think about holding the paper to your chest where your heart is.

The heart consists of 2 types of valves. Valves are like doors. Their purpose is to prevent the
backflow of blood leaving the heart. The first pair of valves are called atrioventricular valves
(AV for short) while the second pair of valves are known as semilunar valves. The AV valves are
found between the atria and ventricles of the heart. The AV valve on the right side is called the
tricuspid valve while the one on the left is called the bicuspid or mitral valve.

right – tri

bi – left

To note:

The left side has thicker walls because it needs to pump the blood under higher pressure than
the right side. This oxygen-rich blood also travels a further distance than blood passing
through the right side.

The Vena cava – largest vein in body

The Aorta – largest artery in the body

Pulmonary means related to the lungs.

Blood cells are occasionally called erythrocytes.

The Arteries take blood away from heart while veins take blood to heart

To explain the process of circulation:

 Deoxygenated blood coming from the body flows into the right atrium via the vena cava
 Once the right atrium has filled with blood the heart gives a little beat and the blood is
pushed through the tricuspid (atrioventricular) valve into the right ventricle
 The walls of the ventricle contract and the blood is pushed into the pulmonary
artery through the semilunar valve which prevents blood flowing backwards into the
heart
 The blood travels to the lungs and moves through the capillaries past the alveoli where
gas exchange takes place (this is why there has to be low pressure on this side of the heart
– blood is going directly to capillaries which would burst under higher pressure)
 Oxygenated blood returns to the left atrium via the pulmonary vein
 It passes through the bicuspid (atrioventricular) valve into the left ventricle
 The thicker muscle walls of the ventricle contract strongly to push the blood forcefully
into the aorta and all the way around the body
 The semilunar valve in the aorta prevents the blood flowing back down into the heart
The blood vessels aid in transport. They are arteries, veins and capillaries. *I doubt this will
show up, but it’ll help you understand just briefly skim over it.

Arteries

 Carry blood at high pressure away from the heart

 Carry oxygenated blood (other than the pulmonary artery)
 Have thick muscular walls containing elastic fibres
 Have a narrow lumen
 Speed of flow is fast

Veins

 Carry blood at low pressure towards the heart

 Carry deoxygenated blood (other than the pulmonary vein)
 Have thin walls
 Have a large lumen
 Contain valves
 Speed of flow is slow 
Difference:

 They usually differentiate between these two note the appearance of valves in veins.

Capillaries

 Carry blood at low pressure within tissues

 Carry both oxygenated and deoxygenated blood
  Have walls that are one cell thick
 Have ‘leaky’ walls
 Speed of flow is slow

The arrangement of vessels:

Blood is composed of red blood cells, white blood cells, platelets and plasma.
How to differentiate from each component

 Plasma is important for the transport of carbon dioxide, digested food (nutrients), urea,
mineral ions, hormones and heat energy
 Red blood cells transport oxygen around the body from the lungs to cells which require it
for aerobic respiration
o They carry the oxygen in the form of oxyhaemoglobin
 White blood cells defend the body against infection by pathogens by carrying
out phagocytosis and antibody production
 Platelets are involved in helping the blood to clot

White blood cells

This component aids in immunity and hence can be linked. White blood cells are part of the
body’s immune system, defending against infection by pathogenic microorganisms

There are two main types, phagocytes and lymphocytes

Phagocytes

 Carry out phagocytosis by engulfing and digesting pathogens.

  Phagocytes have a sensitive cell surface membrane that can detect chemicals produced by
pathogenic cells
 Once they encounter the pathogenic cell, they will engulf it and release digestive
enzymes to digest it
 They can be easily recognised under the microscope by their multi-lobed nucleus and
their granular cytoplasm

Lymphocytes

 Produce antibodies to destroy pathogenic cells and antitoxins to neutralise toxins released

by pathogens
 They can easily be recognised under the microscope by their large round nucleus which
takes up nearly the whole cell and their clear, non-granular cytoplasm
Platelets

 Platelets are fragments of cells which are involved in blood clotting and forming scabs
where the skin has been cut or punctured
 Blood clotting prevents continued / significant blood loss from wounds
 Scab formation seals the wound with an insoluble patch that prevents entry of
microorganisms that could cause infection
 It remains in place until new skin has grown underneath it, sealing the skin again
Process:

 When the skin is broken (i.e. there is a wound) platelets arrive to stop the bleeding
 A series of reactions occur within the blood plasma
 Platelets release chemicals that cause soluble fibrinogen proteins to convert into insoluble
fibrin and form an insoluble mesh across the wound, trapping red blood cells and
therefore forming a clot
 The clot eventually dries and develops into a scab to protect the wound from bacteria
entering

To summarize sticky platelets, appear at the wound and release thromboplastin. Thromboplastin
acts on prothrombin to be converted to thrombin. Thrombin change fibrinogen to fibrin, fibrin is
the end product to trap red blood cells and prevent escaping. It is a mesh of fibers.
 Irritability

- the ability to detect or sense stimuli in the internal or external environment and to make
appropriate responses.

Key terms
stimulus - change in the environment of an organism
reaction - response to a stimulus
effector - muscles & glands that produce a reaction/response.
receptor - receives stimuli from the environment.
Tropisms - part movement of plants in response to stimuli
Taxic response - Movement of an invertebrate’s entire body in response to an external
stimulus (i.e., towards a favorable condition)
Types of tropisms:
Phototropism
- growth movement in response to light
- shoots are positively phototropic, but roots are negatively phototropic
 Shoots grow towards light but roots away from it
Hydrotropism
- growth movement in response to water
- roots are positively hydrotropic while shoots are negatively hydrotropic
Roots grow towards water but shoots away from it
Geo/gravitropism
- growth movement in response to gravity
- roots are positively geotropic while shoots are negatively geotropic
Roots grow with the force of gravity but roots away from it

Phototaxis - movement of an invertebrate towards light e.g. moths

Aerotaxis - movement of an invertebrate towards oxygen e.g. bacteria
Chemotaxis - movement of an invertebrate towards chemicals e.g.
The experiment to test organisms for taxic responses is the choice chamber.
Link to the experiment: https://www.youtube.com/watch?v=LG1cLm1jOG8
So basically, the animals will move towards the most favorable conditions why? The same
reason they move, to escape danger, for example their skin drying out from too much light etc.
 Movement
- an action by an organism or part of an organism causing a change of position or place.
Locomotion - the movement of whole body of an organism from one place to another. Plants
CANNOT locomote.
Functions of the human skeleton
1. For movement & locomotion
2. For support (to keep the body upright)
3. To assist with breathing (rib cage)
4. For muscle attachment
5. For protection of organs e.g. the rib cage protects the heart & lungs, pelvis
(reproductive organs)
6. For production of blood cells (red & white)
7. For storage of calcium & phosphorus
This all aligns with the reasons for movement: to find better conditions (escape danger), to aid in
the finding of a mate for reproduction, to find food etc. think of reasons you’d go to the mall
after school, you locomote for the AC, to find boys and food like funky chicken.
*Learn the parts outlined in the textbook and note that all skeletal diagrams are in anatomical
position so if you’re struggling to remember on a test lay your hand flat on the table or turn your
foot out. A tip is also to remember the thumb is where the radius is, and the pinky is where the
ulna is. In the foot, the smaller bone has a longer name and it’s on the outside. Another thing, the
humerus can be called the funny bone to remember its name.
The human skeletal system consists in 2 main divisions:
Axial Appendicular
Cranium pectoral girdle (shoulder): also known as the
shoulder joint is made up of the scapula and
clavicle.
Vertebral column pelvic girdle (hip): made up of the pelvis.
Rib cage Long bones of arms and legs; femur,
humerus, fibula, tibia, ulna, radius
Sternum

Bone is living connective tissue made up of a hard matrix. This matrix consists of tough
collagen fibers, calcium carbonate, calcium phosphate.

Cartilage is connective tissue made of protein and collagen fibers. It is found at the ends of
long bones, in the ear, rib cage, nose, vertebral column etc. Flexibility is required in some of
these places; however, the main function of cartilage is to reduce friction and prevent shock
between bones.
Think about vertebroarterial discs so if you’re picking up a heavy box incorrectly and you “slip a
disc” the cartilage between the vertebrae are worn away causing immense friction.
The wearing away or degeneration of cartilage can result in bones rubbing friction and bones
breaking if not treated.
Compact bone vs. Spongy bone
- Found in the outer most layer - Found in the inner most layer
- Surrounds bone - Found on the ends of bone
- Harder, solid part of bone - Softer, perforated/porous part of bone

There are four main types of bones in the body:

1. Long bones - e.g. femur; humerus
2. Short bones e.g. carpals, tarsals
3. Flat bones e.g. ribs, pelvis, cranium
4. Irregular bones e.g. vertebral column,

The vertebral column is made up of a few different sections. Each section is made up of a
specific number of bones.
1. cervical vertebrae – 7 bones
2. thoracic vertebrae – 12 bones
3. lumbar vertebrae – 5 bones
4. sacral vertebrae – 5 fused bones
5. coccyx vertebrae (tail bone) – 4 fused bones

Cervical vertebra - small centrum, 2 vertebroarterial canals, split neural spine

Thoracic vertebra - long neural spine, small neural canal, short transverse process, facet for
attachment of ribs
Lumbar vertebra - short neural spine, long transverse process, large centrum
*Remember them in this order, breakfast at 7, lunch at 12, early dinner at 5= Cervical, thoracic,
lumbar.
 Respiration
Cellular respiration – the process by which living organisms use food as a substrate for the
controlled release of energy. This energy is used to fuel metabolic activities. The process of
respiration is controlled by enzymes.

Aerobic- this process requires oxygen and is defined as the chemical reactions in cells that use
oxygen to break down nutrient molecules to release energy It is the complete breakdown of
glucose to release a relatively large amount of energy for use in cell processes. It produces
carbon dioxide and water as well as releasing useful cellular energy. It occurs in mitochondria.

Equation: glucose + oxygen ------------------- > carbon dioxide + water + energy (ATP)
C 6 H 12 O 6 + 6O 2 ------------------- > 6CO 2 + 6H 2 O + energy (ATP)

Anaerobic- this process does not require oxygen and is defined as the chemical reactions in cells
that break down nutrient molecules to release energy without using oxygen. It is the incomplete
breakdown of glucose and releases a relatively small amount of energy (compared to aerobic
respiration) for use in cell processes. It produces different breakdown products depending on the
type of organism it is taking place in. You need to know the equations for anaerobic respiration
in humans (animals) and the microorganism yeast. It occurs in the cytoplasm.

In animals: Anaerobic respiration mainly takes place in muscle cells during vigorous exercise.
When we exercise vigorously, our muscles have a higher demand for energy than when we are
resting or exercising normally. Our bodies can only deliver so much oxygen to our muscle cells
for aerobic respiration. In this instance, as much glucose as possible is broken down
with oxygen, and some glucose is broken down without it, producing lactic acid instead. There is
still energy stored within the bonds of lactic acid molecules that the cell could use; for this
reason, less energy is released when glucose is broken down anaerobically

In yeast: We take advantage of the products of anaerobic respiration in yeast by using it in bread
making, where The carbon dioxide produced causes dough to rise And in brewing, where The
ethanol produced gives the beer its alcoholic nature The carbon dioxide produced gives beer its
fizz

Equation:
(i) This process occurs in yeast.
glucose -------------------- ethanol + carbon dioxide + energy
C 6 H 12 O 6 -------------------- > C 2 H 5 OH + CO 2 + energy (210 KJ)

(ii) This process occurs in fatigued muscles.

glucose -------------------- lactic acid + energy
C 6 H 12 O 6 -------------------- 2C 3 H 6 O 3 + energy (210 KJ)
Domestic and industrial uses of anaerobic respiration
1. Bread baking
Yeast uses sugar to respire anaerobically. This causes the formation of carbon dioxide bubbles
which cause dough to rise. Heat from the oven causes the bubbles to expand, cooks the dough,
kills the yeast and causes the alcohol to evaporate.
2. Alcohol production (beer, wine)
Yeast is used to make alcoholic drinks. When yeast is added to cereals or fruits containing sugar,
controlled anaerobic respiration occurs aka fermentation. Yeast cells reproduce rapidly during
beer or wine production, until the oxygen runs out. The yeast switches to anaerobic respiration.
Ethanol and carbon dioxide are produced. Spirits can then be made by distillation.
Differentiation
Exercise and respiration:
While exercising, the muscles need additional energy since:
- the breathing rate and volume of each breath increases to bring more oxygen to the muscle
cells and remove the carbon dioxide produced.
- the heart rate increases, to pump extra blood containing oxygen to muscles and remove the
carbon dioxide produced.

During strenuous exercise, however, when the oxygen supply becomes too little to supply the
demands of aerobic respiration, muscles respire anaerobically. Lactic acid, a toxic waste
product, is released causing muscle fatigue. This results in an oxygen debt (your body is owed
oxygen). In large quantities lactic acid is toxic to cells and build up can harm muscles and even
cause collapse. Rest and deep breathing are necessary to 1. Repay the oxygen debt and 2.
Breakdown/convert/oxidize lactic acid into carbon dioxide and water.
Effect of smoking on the respiration process:
 Diseases
Hypertension:

High blood pressure is a common condition that affects the body's arteries. It's also called
hypertension. If you have high blood pressure, the force of the blood pushing against the artery
walls is consistently too high. The heart has to work harder to pump blood.

Blood pressure is measured in millimeters of mercury (mm Hg). In general, hypertension is a

blood pressure reading of 130/80 mm Hg or higher.

Symptoms:

 Headaches

 Shortness of breath

 Nosebleeds
Cause
Blood pressure is determined by two things: the amount of blood the heart pumps and how hard
it is for the blood to move through the arteries. The more blood the heart pumps and the narrower
the arteries, the higher the blood pressure.
Treatment

 Eating a heart-healthy diet with less salt

  Getting regular physical activity

 Maintaining a healthy weight or losing weight

 Limiting alcohol

 Not smoking

 Getting 7 to 9 hours of sleep daily

Diabetes:

Diabetes mellitus refers to a group of diseases that affect how the body uses blood sugar
(glucose). Glucose is an important source of energy for the cells that make up the muscles and
tissues. It's also the brain's main source of fuel.

The main cause of diabetes varies by type. But no matter what type of diabetes you have, it can
lead to excess sugar in the blood. Too much sugar in the blood can lead to serious health
problems.

Symptoms:

 Feeling more thirsty

 Urinating often,
contracting UTI’s

 Losing weight
without trying.

 Presence of ketones
in the urine. Ketones
are a byproduct of the
breakdown of muscle
and fat that happens
when there's not
enough available
insulin.

 Feeling tired and

weak.

 Feeling irritable or having other mood changes.

  Having blurry vision.

 Having slow-healing sores.

Cause

Insulin is a hormone that comes from a gland behind and below the stomach (pancreas) and is
released into the bloodstream. The insulin circulates, letting sugar enter the cells. Insulin lowers
the amount of sugar in the bloodstream so as the blood sugar level drops, so does the secretion of
insulin from the pancreas. sugar builds up in the bloodstream. This is because the pancreas
doesn't produce enough insulin.

Treatment

 Eating a heart-healthy diet with less salt

 Getting regular physical activity

 Maintaining a healthy weight or losing weight

 Monitoring blood sugar levels

 Taking insulin injections

N.B., the treatment for each is relatively similar, eat healthy, exercise, maintain weight.