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

Living organisms reproduce so life can continue Living organisms grow Living organisms produce waste like carbon

dioxide

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 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.

Organs

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

Organs working together form systems

Give examples of systems….

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

http://www.youtube.com/watch?v=Ow0jH2Eg8v4

http://www.youtube.com/watch?v=pvOz4V699gk&feature=related

Cell

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 Multi-cellular: Organisms made up of

more than one cell or a system of cells.

Unicellular: Single celled organisms

Specialized

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

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

Microscopes

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

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

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

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

Topic 4: Plant and Animal Cells

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

Organelles

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

http://www.youtube.com/watch?NR=1&v=LP7xAr2FDFU&feature=endscreen

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

Plant Cell

Animal Cell

Differences Between Plant and Animal Cells

Plant CellsAnimal 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

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

http://www.bbc.co.uk/schools/gcsebitesize/science/add_aqa/cells/

Osmosis

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! 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…

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 Example: Digestive System

1. Made up of many organs such as the intestines and the stomach.

2. 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.

3. The connective tissue is made up of loose, fibrous sheets that connect and support the body.

Topic 5: Systems

The Body Systems

1. Digestive System: Used to take in food and break it down into usable energy then pass waste out of the body.

2. Respiratory System: Used to take in oxygen and give off carbon dioxide in the lungs.

3. 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

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

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

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.

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

http://www.learnalberta.ca/content/ngs/index.html?ID1=&action=v&video=humanbody2ps_cac.smil

4. Excretory System

Filters waste materials

from the blood. Kidneys are the

key organ

http://www.youtube.com/watch?v=TZMJeZL-BVg (intro) http://www.learnalberta.ca/content/ngs/index.html?

ID1=&action=v&video=circulatoryandresp_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

1. 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!

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.

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

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

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 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

Vaccines

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

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.