Download 1 Light Microscopes Electron Microscopes • The simplest form of

Human Biology Science 1 – Organisation of the body
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Light Microscopes
The simplest form of microscope
normally found in schools.
Uses light to magnify the object.
Light microscopes have low
resolution so the image can be of
poor clarity.
Can magnify up to 4000 so can be
used to get detailed information from
the mass of a cell structure but not as
detailed and tiny as the electron
microscope.
Both living and dead organisms can
be used with a light microscope.
The specimen can be viewed directly
through the eye.
This type of microscope is much
cheaper to use.
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Electron Microscopes
This microscope is more technical
and often used by scientists.
Uses a beam of electrons to magnify
the object.
These microscopes have 250 times
more resolution power than light
microscopes so therefore have more
accurate clarity on the image.
The magnification in electron
microscopes is also significantly more
than in light microscopes allowing
cells to be viewed with much more
detail allowing scientists to dissect
and observe tiny organisms.
Only dead organisms can be viewed
with an electron microscope as it
needs to be fixed to the slide.
The specimen can only be seen
through fluorescent light.
These microscopes are very
expensive.
TAQ 2.
b)
Organelle
Ribosome
Function of Organelle
Ribosomes function to read the code
represented by messenger RNA which is
formed from the cell’s main DNA. Proteins
are synthesised from this code meaning that
the synthesis of all new proteins occurs from
the ribosomes.
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Human Biology Science 1 – Organisation of the body
Chromatin
The main function of chromatin is to package
the DNA into a smaller volume so that it fits
inside the cell. It is responsible for protecting
the DNA from damage while it is contained in
the cell. Chromatin also controls gene
expression and DNA replication.
ER supplies a surface area for chemical
reactions to take place. It also transports
molecules from one part of the cell to
another once the proteins produced in the
rough ER move into the smooth ER.
Rough ER stores newly synthesised proteins
and also produces insulin and antibodies in
some cell types.
Smooth ER is responsible for the synthesis
of fatty acids known as lipids and also
assists with the detoxification of any
chemicals or drugs found within the liver
cells. In the muscle cells the smooth ER
helps with the contracting of muscles while in
the brain cells it synthesis hormones.
Golgi apparatus is responsible for modifying,
organising and packaging the proteins and
lipids which it receives from the endoplasmic
reticulum; these are then transported to the
plasma membrane. It also produces
lysosomes and secretory vesicles which are
used for the transportation of the molecules.
Flagella have an identical structure to cilia,
the only difference being in size. Flagella are
hair like organelles which are responsible for
moving liquid substances along the surface
of the cell or enabling a single cell to swim
such as the sperm cell.
The primary function of mitochondria is to
produce energy. It is responsible for cellular
respiration, breaking down glucose
molecules to generate ATP which the cell
then uses for energy. Mitochondria have two
membranes an outer and an inner, the inner
is contains many folds. They also have their
own DNA and also their own ribosomes.
The nucleus contains most of the genetic
units of the cell, these are genes. The
nucleus is the centre of the cell and is
responsible for controlling all activity within
the cell. The nucleus produces ribosomes
which leave through the nucleus pores into
the cytoplasm.
Lysosomes are responsible for breaking
down food and waste molecules into smaller
molecules through the use of strong
digestive enzymes. They digest old cell
particles and help remove any bacteria within
Rough Endoplasmic Reticulum
Smooth Endoplasmic Reticulum
Golgi Apparatus
Flagella
Mitochondria
Nucleus
Lysosome
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Human Biology Science 1 – Organisation of the body
the cell.
c)
Red blood cells contain haemoglobin and are responsible for carrying oxygen around the
body; the fact that they are small in size allows them to pass through narrow capillaries. Red
blood cells do not contain a nucleus and other organelles this means that there is more
space inside the cell for haemoglobin.
Ciliated epithelial cells have tiny hair like structures on top of the tissue; cilia are the tiny hair
like structures while epithelial are the tissue type. These cells are found throughout the body,
one example would be in the respiratory track where the cilia move together in unison to
move dust particles or mucus to the back of the throat so that it can be swallowed. There are
many mitochondria found in these cells, they release energy from food to provide energy to
make the cilia move.
The spermatozoa’s tail is an example of flagella, which is used to move the cell and allow
them to swim in the female genital tract. The oval head of the sperm cell contains the
nucleus which holds genetic information and chromosomes; it also has enzymes which help
the sperm cell penetrate the egg membrane. The middle section of the sperm cell is tubular
containing mitochondria which provide the energy to enable the sperm to swim in the female
genital tract.
TAQ 3.
“The cell membrane is a fluid mosaic model made of lipids and protein molecules.”
The cell membrane has an important function controlling what substances pass in and out of
the cell. The organisation of the cell membrane is described as fluid due to the fact the
molecules are always changing position to support as other so if a molecule is removed from
the cell or damaged the remaining can merge together; this assists the internal organelles to
carry out their functions. The term mosaic is used as the cell membrane is made up from
many different small molecules of proteins and lipids. The membrane itself is a lipid bilayer
composed from a phospholipid in which the lipids are hydrophobic molecules while the
phosphate molecules are hydrophilic; therefore the membrane forms when the two parts of
the molecule point in opposite directions, the lipid half trying to avoid the watery atmosphere
point in while the phosphate half being attracted to it points out.
TAQ 4.
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Human Biology Science 1 – Organisation of the body
a)
Active transport: This is the movement of molecules along the cell membrane from a lower
to a higher concentration gradient.
Diffusion: This is when the molecules move along the membrane from a high to a low
gradient.
Osmosis: This is when water molecules move through a selectively permeable membrane
from a high to low concentration gradient.
b)
Feature
1. Use of energy
Diffusion
Uses channel
proteins to move
through gradients
and does not require
the use of energy
unlike active
transport.
2. Concentration
gradient
During this process a
substance will move
from a high to low
concentration
gradient.
3. Substances
transported
Substances that can
be dissolved will be
transported through
diffusion such as
oxygen, carbon
dioxide and lipids.
4. Importance
Diffusion is very
important in the
movement of
substances in and
out of the body to
maintain equilibrium,
by diffusing waste
substances such as
carbon dioxide out
and oxygen into the
body.
Osmosis
Similar to diffusion,
osmosis does not
require the use of
energy, however as it
the movement of
water molecules it is
important to control
the water levels in
the body.
Like diffusion, during
osmosis the water
molecules move from
a high gradient of
concentration to a
lower one, the higher
being the purest form
of water.
Water molecules can
move freely through
permeable
membranes however
substances such as
sugars cannot be
transported in this
way.
Osmosis helps to
influence the
distribution of
nutrients throughout
the body and
removes waste from
the body.
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Active transport
This process does
requires energy
which it energy
receives from
respiration using
ATP and the
mitochondria controls
the release of the
energy.
When active
transport takes
place, the substance
moves from a low to
high gradient of
concentration.
Active transport
moves substances in
to and out of the
cells; the substances
moved through
active transport
include glucose,
proteins, ions and
large cells.
Active transport of
substances is very
important in
distributing the
equilibrium created
by diffusion as some
substances require
energy from the
protein in order to
enter the cell quickly.
Human Biology Science 1 – Organisation of the body
TAQ 5.
Type of tissue
Describe how the structure of the tissue
is linked to function
Nervous tissue is responsible for controlling
and coordinating bodily functions and
consists of two types of cells, these are
neurons and neuroglia.
The neurons are sensitive to stimuli which
are transferred into nerve impulses all over
the body such as muscles and glands.
Neuroglia do not control nerve impulses but
are very important in supporting the neurons
in the brain and spinal cord by interlinking
around them, some neuroglia are also used
to attach the neurons to the connective
tissue so as to allow the nerve cells to carry
out their function without being damaged.
Muscle tissue is categorised into three types,
those are skeletal, cardiac and smooth.
Skeletal muscle is attached to the bones and
is striated, which means the fibres have light
and dark bands and many nuclei located on
the outskirt of the cell, this is the kind of
muscle used for quick movements which are
voluntary as they can be controlled to
contract or relax.
Cardiac muscle makes up the majority of the
heart wall, it is also striated however it is
involuntary and it never tires, allowing it to
continuously pump blood around the body.
Smooth muscle can be found in any hollow
internal structure such as intestines or
stomach; they expand and contract allowing
these internal organs to carry out their
functions and are considered involuntary.
Connective tissue is largest amount of tissue
found in the body, it has cells scattered
throughout the body in an extracellular
matrix. The main function of this tissue is to
join together and support other tissues types
in the body while insulating and protecting
internal organs. Blood is a fluid connective
tissue and is the main transport system
throughout the body, while fat tissue sites
are used for storing energy. Connective
tissue consists of three main components,
cells, ground substances and fibres.
Epithelial tissue covers the entire surface
area and any cavities of the body. The cells
in epithelial tissue are very tightly packed
together and therefore one function of this
tissue is protection in the form of a barrier
such as skin, with protects internal organs
Nerve tissue
Muscle tissue
Connective tissue
Epithelial tissue
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Human Biology Science 1 – Organisation of the body
from damage. The majority of glands within
the body are formed from epithelial tissue
where it is used for the secretion of
hormones and other substances from the
body. Certain areas of epithelial tissue
contains nerves such as the tongue and skin
so therefore this tissue also has a sensory
function working with the nervous tissue
identifying sensations.
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Human Biology Science 1 – Organisation of the body
TAQ 6.
Epithelial cells
found in the
bronchioles line
the inner surface of
the lungs.
Myocardium forms the
bulk of the heart wall
and is the cardiac
tissue.
Pericardium is the
double walled sac
containing the heart
and is made up from
connective tissue.
Ciliated epithelial
cells can also be
found in the lungs to
move any mucus.
Endocardium is the
innermost, thin, smooth
epithelial tissue found
in the inner surface of
all the hearts chambers
and valves.
Bronchioles are the main
tissue type found in the lungs,
they have smooth muscle cells
to control airflow.
The heart is a main organ of the body; its main function is to pump blood around the body
through the circulatory system. Deoxygenated blood leaves the through the right side of the
heart via the pulmonary artery, while the left side pumps fresh oxygenated blood through the
body via the arteries and capillaries supplying all the body’s tissues with oxygen.
The lungs are also major organs of the body in the respiratory system, enabling us breathe.
The process of breathing is controlled by the nervous system automatically.
The lungs are also very closely linked with the cardiovascular system, working with the heart
to transport oxygen around the body. When we breathe in air through our lungs the oxygen
is absorbed into the blood stream which the heart then sends to our tissues and muscles to
allow for movement. Once the oxygen has been used carbon dioxide is then produced and
absorbed into the blood stream, this is then pumped back to the heart and then the lungs
where it is expelled as we exhale and take in fresh oxygen.
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Human Biology Science 1 – Organisation of the body
Reference & Bibliography
Abpi Bringing medicines to life Resources for schools, Diffusion, osmosis and active
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igation_allTopic=1 [Accessed on 10 December 2014.]
Bailey, R. Connective Tissue About education [online.] Available at:
http://biology.about.com/od/anatomy/a/aa122807a.htm [Accessed on 10 December 2014.]
Bailey, R. The Lungs About education [online.] Available at:
http://biology.about.com/od/anatomy/ss/the-lungs.htm [Accessed on 10 December 2014.]
Biology Mad, Microscopy [online.] Available at:
http://www.biologymad.com/cells/microscopy.htm [Accessed on 8 December 2014.]
Council-Garcia, L., C. 2002. Cell structure and function UNM Biology Undergraduate Labs
[online.] Available at: http://biology.unm.edu/ccouncil/Biology_124/Summaries/Cell.html
[Accessed on 10 December 2014.]
Grabowski, R. S., Tortora, J. G., 1996. Principles of anatomy and physiology 8th ed. United
States of America: Harper Collins.
Lewis, T., 23 May 2013. Human Heart: Anatomy, Function & Facts Live Science [online.]
Available at: http://www.livescience.com/34655-human-heart.html [Accessed on 10
December 2014.]
The McGraw-Hill companies. Cardiovascular System: Heart [picture][online.] Available at:
http://www.rci.rutgers.edu/~uzwiak/AnatPhys/Cardiovascular_System.html [Accessed on 11
December 2014.]
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