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Unit 11 - Assignment 4 - P1
Organelles:
Mitochondria – Mitochondria are membrane-bound structures where cellular respiration takes
place, which converts food into useful chemical energy in the cell
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Mitochondria consist of two membranes; both
phospholipid bilayers
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The membrane has membrane proteins and pores which transports molecules
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The inner
membrane does not have pores or channels; it is very impermeable
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There are two regions in the endoplasmic reticulum, the rough ER and the smooth ER
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It is an area
for vesicles to transport the produce of the ER to several places in the body
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Rough endoplasmic reticulum – The rough endoplasmic reticulum consists of flattened sacs and
tubules
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The
rough endoplasmic reticulum produces membranes and secretory proteins
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In pancreatic cells, the rough ER produces insulin
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Ribosomes – This is where protein synthesis occurs, creating a chain of amino acids linked by
polypeptide bonds
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Both are made up of rRNA and protein
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Nucleus – Contains DNA (deoxyribonucleic acid) which controls the activities of the cell
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The nucleus is a membrane bound structure which controls the
cells growth and reproduction
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Nuclear pore - The nuclear pore is a protein-lined channel in the nuclear envelope that regulates the
transportation of molecules between the nucleus and the cytoplasm
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It then sends
them out to the rest of the cell to form into complete ribosomes
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Nuclear membrane – The nuclear membrane keeps the DNA inside the nucleus to protect it from
surrounding substances in the cytoplasm
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The nuclear membrane consists of two membranes which produces a barrier between the
nuclear contents and the cytosol
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The inner nuclear membrane contains peripheral and integral proteins which
provide stability to the lamina
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The outer nuclear membrane is next to the ER, both covered with ribosomes
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They transport materials from one place
to another
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They have a completely selfcontained environment which differs from the inside of the cell
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The core structure
of the membrane is the phospholipid bilayer
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These proteins in the phospholipid
bilayer have specific functions of the plasma membrane
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Golgi apparatus – The Golgi apparatus processes and packages the macromolecules like proteins and
lipids which synthesise the cell
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It has the structure of membrane-bound
sacs called cisternae
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They contain digestive
enzymes which digest excess or 'worn out' organelles, food particles, bacteria and viruses
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Centrioles - Centrioles are in animal cells
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Centrioles are made up of nine groups of arranged microtubules in the nucleus
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When it
occurs, there are groups of mitotic spindle attached to the centrioles
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bp
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Large
surface area
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Squamous - Allow
material to pass by
diffusion, filtration and
secretes lubricating
substance
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Cuboidal Hexagonal shaped
cells
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Single
layer of cells
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Columnar - Absorbs; also
secretes mucus and
enzymes
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Cells connected by
tight junctions
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Cells which
have hairs coming
out from them
(cilia)
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Simple epithelial tissue are not
multi-layered, unlike stratified
epithelial tissue
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Unlike ciliated epithelial tissue,
stratified and simple epithelial
tissue do not have cilia
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Stratified
epithelial

Squamous - Flat,
scale-like
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Selectively
permeable
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Cuboidal - Columnshaped cells
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Columnar - Cube
shaped cells
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Dense
connective

made up of two
layers
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Crowded between
the collagen fibres
are rows of fibreforming cells
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Also
makes up the lower
layers of skin
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It holds organs in place
and attaches epithelial
tissue to other
underlying tissues
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Unlike dense connective
tissue, loose connective tissue
has fibroblasts spread out in
the tissue
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Loose
connective

Supporting
connective

Separated by a
gelatinous
substance made up
of collagenous and
elastic fibres
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Hyaline cartilage Perichondrium is a
fibrous strip
bordering the
cartilage
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Large,
spherical cells
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Elastic cartilage Same as hyaline
cartilage, but more
elastic fibre
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Is more flexible and
elastic
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Forms the
earliest skeleton in the
foetus
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It permits the
elongation of long
bones
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Cartilage
cells are arranged
between bundles
often in rows
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The
lacunae around the
chondrocytes are
lined with intensely
staining capsules
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Fluid
connective

Sensory
nervous

Motor
nervous
Skeletal
muscle

Blood and lymph
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Lymph is made up
largely of
lymphocytes in a
fluid
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Two main cell
types, neurons and
neuroglia
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Most of the cell
bodies are located
in the CNS
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The neuroglia provide
support for the neurons
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A single
skeletal muscle cell
is long and
approximately
cylindrical in shape,
with many nuclei
located at the
edges of the cell
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The lymph and is largely
responsible for the
immune system
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Sensory and motor nervous
tissue both have neurons
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Transmits impulses away
from the CNS to muscles
and glands
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The cells are long unlike
smooth muscle tissue cells
which are small and tapered
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Each
smooth muscle
fibre has a single
centrally located
nucleus
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The fibres
are attached at
their ends to
adjoining fibres by
thick plasma
membranes called
intercalated discs
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In
the digestive system the
action of smooth muscle
helps move food along
the gastrointestinal tract
whilst breaking the food
down further
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Pumps blood through
the heart
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tissue cells which have a
centrally located nucleus
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Cardiac muscle have
intercalated discs, unlike
smooth and skeletal muscle
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4 types of tissue
Lungs:

At the end of each alveolar duct there are a number of sac-like structures called alveoli, it is within

these structures that surfactant is produced
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Gas exchange of oxygen and carbon dioxide
takes place in the alveoli
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The oxygen is then carried by the blood to the body
tissues
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It then
diffuses across the capillary and alveolar walls into the air to be removed from the body with
expiration
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The walls are
extremely thin
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They also are surrounded by numerous capillaries
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The elongated muscle
fibres shorten and move body parts to fulfil their function
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The quantity of muscle fibres within the tissue determines how
strong, more developed and how big the muscle tissue is
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Also smooth muscle fibres are small and tapered; the ends reduce in size
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This helps the muscle tissue achieve its function
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The striated muscle
collagen fibres shorten and move body parts to fulfil their function
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The
more developed the muscle tissue is (the more muscle fibres) means that the function will be carried
out more effectively; pumping the blood through the heart
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When the muscle contracts, the fibres decrease in diameter
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The nucleus contains DNA (deoxyribonucleic acid) which controls the activities of the cell
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The nucleus is a membrane bound structure which controls the
cells growth and reproduction
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Small intestine:

More chemical energy means a greater performance
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The structure of the cytoplasm helps the cell achieve its function, the fact
that it is a jelly-like liquid means it can take any form to help the cell stay turgid
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The cytoplasm helps the cell achieve its function: to breaks
down waste (enzymes) and aid metabolic activity
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The nuclei in the cells controls the cell growth and reproduction
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e
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Unit 11 - Assignment 4 - D1
Cell Function

Level 1

Cells

Examples
of each
Red blood
cells
Cardiac
muscle
cells

For each example show how the function at that level depends
on the structure provided by the previous level
Red blood cells are the most common type of blood cell
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Red blood cells take up oxygen in the lungs
and release it into tissues while squeezing through the body's
capillaries
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e
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They lack a cell nucleus and most organelles, in
order to accommodate maximum space for haemoglobin
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This structure provides
properties needed for the cell function
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Intercalated discs contain gap
junctions and desmosomes
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This is so that the cells contract simultaneously
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Ciliated
Ciliated epithelial tissue is made up of lined up ciliated epithelial
epithelium cells
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The cilia help cells move along the tissue or can help debris and
Cardiac
waste move along the surface of the cells
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Particles in the air are
trapped by the mucus in these passageways and the sweeping
motions of the cilia direct the mucus away from the lungs and
out of the body
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The
cilia on the edges of the cells are made up of microtubules
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These microtubules
bind together to form pairs, which form a cylindrical shape for
more strength
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They extend up through each of the cilium hairs on the
surface
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These
enzymes connect to the cell’s fibres and move them in pulsing
waves
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The striated muscle collagen fibres shorten and
move body parts to fulfil their function
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The more developed the
muscle tissue is (the more muscle fibres) means that the
function will be carried out more effectively; pumping the blood
through the heart
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When the muscle contracts,
the fibres decrease in diameter
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Cardiac muscle cells are in the heart
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Cardiac muscle is considered to
be an involuntary tissue because it is controlled unconsciously
by regions of the brain stem and hypothalamus
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The cells of cardiac
muscle tissue are shorter than skeletal muscle tissue and form a

Level 3

Organs

Heart
Lungs

network of many branches between the cells
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The cells do not fuse during
development, leaving each cell with a single nucleus
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The presence of myofibrils and many
mitochondria in cardiac muscle cells provides them with great
strength and endurance to pump blood
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The heart is a
muscular organ that functions as the body’s circulatory pump
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This provides oxygen and nutrients to body tissues by
transporting the blood throughout the body
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The atria are smaller than the
ventricles and have thinner, less muscular walls than the
ventricles
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They
are connected to the veins that carry blood to the heart
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The ventricles are connected to the
arteries that carry blood away from the heart
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The right side of the heart maintains
pulmonary circulation to the lungs while the left side of the
heart pumps blood all the way to the body in the systemic
circulatory loop
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The heart wall is made of 3 layers: epicardium, myocardium and
endocardium:
• The epicardium is the outermost layer of the heart wall
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• The myocardium is the muscular middle layer of the
heart wall that contains the cardiac muscle tissue
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• Endocardium is the simple squamous endothelium layer
that lines the inside of the heart
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The atria of the heart have a very thin myocardium because
they only have to pump blood to the ventricles
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The lungs fill the chest cavity and make up most of the lower
respiratory tract
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Each lung is divided into lobes
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Each lung has a bronchial tree
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The air-filled sacs called alveoli
in the lungs are lined with mucus
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The
mucus in the trachea and bronchi is sticky so it traps any dust
and micro-organisms which you breathe in
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The cilia move
back and forth to sweep the mucus upwards towards the throat
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The mucus
is usually swallowed
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After a person
exhales, the lungs stay partly inflated because of a fluid called
surfactant that is produced by special cells and secreted within
the alveoli
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The lungs work with the heart to circulate oxygen throughout
the body
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The pulmonary artery transports blood from the heart to
the lungs
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The
left pulmonary artery extends to the left lung and the right
pulmonary artery to the right lung
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Oxygen diffuses across
the thin epithelium of the alveoli sacs into the blood within the
surrounding capillaries
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The oxygen rich
blood is returned to the heart via the pulmonary veins
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