Transcript Unit 2: Cells and Systems

Unit 2: Cells and
Systems
Science 8
Topic 1: Characteristics of Living
Things
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Structure, Function and Organization
Characteristics of Living Organisms
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Living organisms need energy, they get it from
food
Living organisms respond and adapt to their
environment
Living organisms reproduce so life can continue
Living organisms grow
Living organisms produce waste like carbon
dioxide
Levels of Organization
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Cells → Tissue→ Organs→ Systems
The cell is the smallest, or basic, unit of every
system. A cell is the smallest thing scientists
consider to be alive.
 Cells with the same structure and function are
grouped into tissues.
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4 Main Types of Tissue Found in
Animals
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Muscle tissue: Move the parts of the body
Nerve tissue: Carries signals between the brain
and other body parts to co-ordinate activities.
Epithelial tissue: Protects the outside of the
body and covers the internal structures, such as
intestines.
Connective tissue: Connects and supports
different parts of the body. May be solid like
bone or fluid like blood.
3 Main Types of Tissue Found in
Plants
Epidermal tissue: (Skin) protects the
outside of the plant. Also gives structure
to the plant.
 Xylem tissue: Vessels transport water
absorbed by the roots, throughout the
plant.
 Phloem tissue: Vessels transport the
glucose to other parts of the plant.
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Organs
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Organs: Distinct structures in your body that
perform particular functions.
E.g. Brain, eyes, kidneys…
Other examples??
Groups made up of different tissues form
organs
Systems
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Organs working together form systems
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Give examples of systems….
Different Organisms Have Similar
Functions
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Plants gather food through roots and by
bending; animals move around
Movement in the environment: birds have
wings, whales have flippers
Food gathering structures: barnacles have
tentacles, birds have bills
Breathing structures: gills vs. lungs
Topic 2: The Role of Cells Within
Living Things
http://www.youtube.com/watch?v=Ow0jH2
Eg8v4
 http://www.youtube.com/watch?v=pvOz4V
699gk&feature=related
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Cell
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Cell: The basic unit of every system. “The
building block of life, all living things are
made up of cells”
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It separates all forms of life from non-living
things.
All living things are made up of cells!
Cells can be very specialized to suit a system in
the body.
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Single-celled and Multi-celled
organisms
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Multi-cellular: Organisms made up of
more than one cell or a system of cells.
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Unicellular: Single celled organisms
Specialized
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Cells need to be specialized to meet the different
needs just like a band needs to have different
instruments to play a variety of songs.
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Cells in multi-cellular organisms are said to be
specialized for different jobs.
The Advantages of being Multi-cellular
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Unicellular organisms have to be able to move,
eat, reproduce and respond to environments.
Because they depend on cell membranes they
can only live in watery, food rich environments.
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Multi-cellular organisms can live in a wide
variety of environments; by specializing they can
be much more efficient.
Topic 3: The Microscope
Microscopes
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Magnifying: Making something appear larger.
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Early Microscopes: Anton van Leeuwenhoek
invented one of the first microscopes using
different glass lenses. He was able to magnify
up to 300 times the size of an object. Robert
Hooke was also experimenting by looking at
pieces of cork under magnification. He
described what he saw as cellulae “little rooms”
giving us the present-day word “cell”
Microscope view of cork
Types of Microscopes
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Light Microscope: 2,000 x magnification
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Electron Microscope: 2,000,000 x
magnification (must be in a vacuum
therefore dead cells only)
Parts of a Microscope
Field of View
Objective Diameter Of Field Of View Magnification (10x
Ocular)
4x 4.0 mm (4.45) 40x
10x 2.0 mm (1.78) 100x
40x 0.4 mm (0.45) 400x
100x 0.2 mm (0.178) 1000x
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http://www.learnalberta.ca/content/seb20/h
tml/imageCollections/index.html?URL=mic
roscope_20.html (slide pictures)
Topic 4: Plant and Animal Cells
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http://www.learnalberta.ca/content/seb20u/
html/virtualMicroscope/index.html (virtual)
Organelles
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Organelles: Structures inside the cell.
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Cytoplasm: Jelly-like material in which other parts of the cell float.
Cell membrane: Surrounds the cell and protects the cells contents.
Cell wall: Thick covering outside the cell membrane
Nucleus: Controls most of the cells activities
Vacuole: Liquid filled part for storage; smaller and more in animal
cells
Chloroplast: Contains the green pigment chlorophyll.
Mitochondria: Powerhouse of the cell
Rough Endoplasmic Reticulum: Where chemical activity occurs,
transportation of proteins
Smooth Endoplasmic Reticulum: Where chemical activity occurs,
storage of proteins
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http://www.youtube.com/watch?NR=1&v=
LP7xAr2FDFU&feature=endscreen
 http://www.youtube.com/watch?v=rABKB5
aS2Zg&feature=related (song)
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Plant Cell
Animal Cell
Differences Between Plant and
Animal Cells
Animal Cells
Plant Cells
Movement of Gases and Liquids
into and out of cells
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Cell Membrane: Is like a border crossing. The
membrane is selectively permeable meaning
that it lets some things across but not others.
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Permeable: Lets everything through
Impermeable: Lets nothing through
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Diffusion
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Diffusion: The random movement of particles
from a high concentration to a low concentration.
E.g. Popcorn smell
Diffusion in Cells: Cells burn oxygen and make
carbon dioxide so there is a high concentration
of CO2 inside a cell and a low concentration of
O2. Diffusion in many cases will allow for a
movement of particles through a membrane
without a cost of energy from the cell.
Diagram of Diffusion
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http://www.bbc.co.uk/schools/gcsebitesize/
science/add_aqa/cells/
Osmosis
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Osmosis: Diffusion of water through a
selectively permeable membrane. Water moves
from a high concentration to a low concentration.
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Fluid Movement in Plants: All the water in a
plant is connected from cell to cell, water taken
in by roots pushes water up (through osmosis)
and water evaporating off of leaves pulls water
(also through osmosis)
Plants Vascular tissue: like blood
vessels for a plant!
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Phloem tissue: Transports sugars manufactured in the
leaves to the rest of the plant.
Xylem tissue: Conducts water and minerals absorbed
by the roots cells to every cell in the plant.
Root hairs: Tiny hair-like roots that serve to increase
the surface area in which osmosis can take place.
From the root hairs water is absorbed into the xylem
tissue, to the stems, then to the leaves. Once in the
leaves it is used by the chloroplasts for photosynthesis.
Plants Continued…
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Stoma (stomata): Are openings in the bottom of
the leaves that let air in and out. Controlled by
the guard cells.
Transpiration: Loss of water from a plant
through evaporation from the leaves and stem.
Contributing Roles of Cells,
Tissues and Organs in Plant and
Animal Structures
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Example: Digestive System
1.
Made up of many organs such as the intestines and
the stomach.
In the stomach, muscle tissue moves to mix stomach
contents. Epithelial tissue lines the stomach.
Connective tissue helps hold the shape. Nerve tissue
co-ordinates the activities of the stomach.
The connective tissue is made up of loose, fibrous
sheets that connect and support the body.
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Topic 5: Systems
The Body Systems
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Digestive System: Used to take in food and
break it down into usable energy then pass
waste out of the body.
Respiratory System: Used to take in oxygen
and give off carbon dioxide in the lungs.
Circulatory System: Transports nutrients and
oxygen to different parts of the body and
carries some waste products.
More Body Systems
4. Excretory System: Filters blood and
removes wastes from system
5. Sensory Awareness (Nervous) System:
Responds to changes in the environment to
keep your body stable.
1. The Digestive System
Food Pathway
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Digestive → Circulatory
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Mouth→ Stomach→ Small Intestine→ Bloodstream via villi
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Villi: Each villi contains a network of capillaries which absorb the digested
food into the blood stream, much the same way as the alveoli.
Villi work by increasing the surface area of the small intestine, so it can
absorb more nutrients
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Food provides nutrients in the form of Carbohydrates, Fats, Proteins,
vitamins, minerals and water that provide energy and materials for growth,
development and repair.
2. The Respiratory System
Air Pathway
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Respiratory → Circulatory
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Bronchus tube → Bronchioles → Alveoli→ Capillaries
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The respiratory system moves the air in and out of the lungs
and the circulatory system picks up oxygen from the lungs
while dropping off carbon dioxide.
The circulatory system carries the oxygen to the parts of the
body that need it via diffusion.
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3. The Circulatory System
Circulatory System CellsWhat is inside of blood?
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Red Blood Cells: Contain hemoglobin and carry
oxygen
White Blood Cells: Defend the body against
sickness/disease and help blood to clot
Hemoglobin: Iron rich chemical found in the
blood that attracts oxygen. Oxygen attaches to
hemoglobin so that it can be transported
throughout the body.
Plasma: Liquid portion of the blood. It carries
food, waste, hormones and blood cells.
Continued…
Platelets: Prevent blood loss
 Blood Vessel: Part of a complex network
of tubes/passageways that serve to bring
things from the external environment to
the internal environment.
 Veins: Pump blood to the heart
 Arteries: Pump blood away from the heart
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http://www.learnalberta.ca/content/ngs/ind
ex.html?ID1=&action=v&video=humanbod
y2ps_cac.smil
4. Excretory System
Filters waste materials
from the blood.
 Kidneys are the
key organ
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http://www.youtube.com/watch?v=TZMJeZL-BVg (intro)
http://www.learnalberta.ca/content/ngs/index.html?ID1=&action=v&video=cir
culatoryandresp_thekidney.smil
http://www.youtube.com/watch?v=XF_lF3J4ZKs (advanced)
http://www.youtube.com/watch?v=aQZaNXNroVY (nephron/system)
http://www.learnalberta.ca/content/sebr/index.html (virtual lab)
http://www.youtube.com/watch?v=TZMJeZL-BVg (intro)
5. Sensory Awareness System
Temperature: A stable internal environment in
your body is desired!
Cold: Shivering makes muscles quiver and
generate heat. Hair stands on end because of
small muscle contractions.
Heat: Blood vessels in your skin expand to
increase blood flow to the surface and release
heat- it’s why you get a red face when you run!
1.
Continued…
2. Exercise:
Increases heart rate, and thus blood flow. Blood is diverted away from
the digestive system and towards muscles so they can obtain
oxygen.
3. Panic:
Feeling ‘afraid’ is a reaction based on your endocrine system and your
nervous system.
- Heart rate increases
- Blood is diverted to needed muscles (e.g. to escape, you need your
leg muscles!)
- Your mouth becomes dry
Continued…
4. Reflexes:
Your nervous system (brain, spinal cord and
nerves) send signals to your body parts in
response to stimuli.
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E.g. The doctor hits your knee with his small
hammer – what happens?
http://www.learnalberta.ca/content/ngs/ind
ex.html?ID1=&action=v&video=nervoussy
stem.smil (nervous system)
 http://www.learnalberta.ca/content/ngs/ind
ex.html?ID1=&action=v&video=humanbod
y1ps_naes.smil (nervous + endocrine)
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Topic 6: Scientific Knowledge
Causes of Digestive System
Disorders
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Low fiber over a prolonged period of time
(skipping meals or eating high sugars) can
be a cause of colon cancer.
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Long term stress, smoking or excessive
use of aspirin and alcohol can lead to
ulcers.
Disorders of the Respiratory
System
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Poison in cigarettes and pollution irritates the
lining of the respiratory system causing extra
mucus to be produced, which is removed by
coughing.
Bronchitis: Inflammation of the bronchial tubes,
if prolonged over time can cause emphysema.
Lung Cancer: Caused by tar in smoke, which
makes certain cells grow out of control.
Common Problems with the
Circulatory System
Hypertension (high blood pressure)
 Strokes
 Heart Attacks
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Vaccines
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Louis Pasteur identified ‘germs’ as living cells.
They are the cause of many diseases, like
smallpox.
Vaccines are inactive versions of the germs that
cause that disease.
The body learns how to fight off a disease when
a small amount of germ cells are introduced.
Nutritional Research
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Early explorers developed scurvy, which is a disease
characterized by bleeding gums, loose teeth, unsteady
gait and sores that would not heal.
A lack of vitamin C in the diet was determined to be the
cause
Food affects the functioning of many organs
Fats turn into cholesterol, which can build up in the walls
of arteries
Bacteria in food can cause the mucus layer in your
stomach to break down – leading to ulcers.