Unit 2 cells and systems
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Unit 2: Cells and Systems. Science 8. Topic 1: Characteristics of Living Things. Structure, Function and Organization. Characteristics of Living Organisms. Living organisms need energy, they get it from food Living organisms respond and adapt to their environment

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Unit 2: Cells and Systems

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Unit 2 cells and systems

Unit 2: Cells and Systems

Science 8

Topic 1 characteristics of living things

Topic 1: Characteristics of Living Things

  • Structure, Function and Organization

Characteristics of living organisms

Characteristics of Living Organisms

  • 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

Levels of Organization

  • 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.

4 main types of tissue found in animals

4 Main Types of Tissue Found in Animals

  • 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

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.



  • 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



  • Organs working together form systems

  • Give examples of systems….

Different organisms have similar functions

Different Organisms Have Similar Functions

  • 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

Topic 2: The Role of Cells Within Living Things

Unit 2 cells and systems



Unit 2 cells and systems


  • Cell: The basic unit of every system. “The building block of life, all living things are made up of cells”

  • 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.

Single celled and multi celled organisms

Single-celled and Multi-celled organisms

  • Multi-cellular: Organisms made up of more than one cell or a system of cells.

  • Unicellular: Single celled organisms



  • 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.

  • Cells in multi-cellular organisms are said to be specialized for different jobs.

The advantages of being multi cellular

The Advantages of being Multi-cellular

  • 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.

  • Multi-cellular organisms can live in a wide variety of environments; by specializing they can be much more efficient.

Topic 3 the microscope

Topic 3: The Microscope



  • Magnifying: Making something appear larger.

  • 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

Microscope view of cork

Types of microscopes

Types of Microscopes

  • Light Microscope: 2,000 x magnification

  • Electron Microscope: 2,000,000 x magnification (must be in a vacuum therefore dead cells only)

Parts of a microscope

Parts of a Microscope

Field of view

Field of View

Unit 2 cells and systems

http://www.learnalberta.ca/content/seb20/html/imageCollections/index.html?URL=microscope_20.html (slide pictures)

Topic 4 plant and animal cells

Topic 4: Plant and Animal Cells

Unit 2 cells and systems

http://www.learnalberta.ca/content/seb20u/html/virtualMicroscope/index.html (virtual)



  • Organelles: Structures inside the cell.

  • 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

Unit 2 cells and systems


http://www.youtube.com/watch?v=rABKB5aS2Zg&feature=related (song)

Plant cell

Plant Cell

Animal cell

Animal Cell

Differences between plant and animal cells

Differences Between Plant and Animal Cells

Movement of gases and liquids into and out of cells

Movement of Gases and Liquids into and out of cells

  • Cell Membrane: Is like a border crossing. The membrane is selectively permeable meaning that it lets some things across but not others.

  • Permeable: Lets everything through

  • Impermeable: Lets nothing through



  • 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

Diagram of Diffusion

Unit 2 cells and systems




  • Osmosis: Diffusion of water through a selectively permeable membrane. Water moves from a high concentration to a low concentration.

  • 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

Plants Vascular tissue: like blood vessels for a plant!

  • 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

Plants Continued…

  • 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

Contributing Roles of Cells, Tissues and Organs in Plant and Animal Structures

  • Example: Digestive System

  • 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.

Topic 5 systems

Topic 5: Systems

The body systems

The Body Systems

  • 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

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

1. The Digestive System

Food pathway

Food Pathway

  • Digestive → Circulatory

  • Mouth→ Stomach→ Small Intestine→ Bloodstream via villi

  • 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

  • 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

2. The Respiratory System

Air pathway

Air Pathway

  • Respiratory→ Circulatory

  • Bronchus tube → Bronchioles → Alveoli→ Capillaries

  • 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.

3 the circulatory system

3. The Circulatory System

Circulatory system cells what is inside of blood

Circulatory System Cells- What is inside of blood?

  • 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.



  • 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

Unit 2 cells and systems


4 excretory system

4. Excretory System

Filters waste materials

from the blood.

Kidneys are the

key organ

Unit 2 cells and systems

http://www.youtube.com/watch?v=TZMJeZL-BVg (intro)


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

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!



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



  • 4. Reflexes:

    Your nervous system (brain, spinal cord and nerves) send signals to your body parts in response to stimuli.

    E.g. The doctor hits your knee with his small hammer – what happens?

Unit 2 cells and systems

http://www.learnalberta.ca/content/ngs/index.html?ID1=&action=v&video=nervoussystem.smil (nervous system)

http://www.learnalberta.ca/content/ngs/index.html?ID1=&action=v&video=humanbody1ps_naes.smil (nervous + endocrine)

Topic 6 scientific knowledge

Topic 6: Scientific Knowledge

Causes of digestive system disorders

Causes of Digestive System Disorders

  • Low fiber over a prolonged period of time (skipping meals or eating high sugars) can be a cause of colon cancer.

  • Long term stress, smoking or excessive use of aspirin and alcohol can lead to ulcers.

Disorders of the respiratory system

Disorders of the Respiratory System

  • 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

Common Problems with the Circulatory System

  • Hypertension (high blood pressure)

  • Strokes

  • Heart Attacks



  • 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

Nutritional Research

  • 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.

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