What is considered a Living Thing?

Notes

Six Characteristics ALL Living Things must have:

1. Made of cells

2. Need energy

3. Grow and develop

4. Respond to the environment

5. Reproduce

6. Adaptations for their environment

1) All living things have Cells.  The cell is the basic unit of life.

• All organisms are made up of at least 1 cell

• Organisms can be made up of multiple cells (humans are made up of trillions of cells, yes trillions)

• Generally, most cells fall into a small range 10-50 micrometers across (hair on average is about 100 micrometers across)

2) All living things need Energy!

• Energy is needed to make things move, to build structures, to stay warm

• Organisms get energy from the environment:

  • Plants (Producers) = Sun

  • Animals (Consumers) = Surrounding environment

Nutrients:

Substances that provide the energy (fat, protein, carbohydrates) and materials (minerals, vitamins) that organisms need to grow, develop, and reproduce

Metabolism: 

The sum of all the different processes that happen inside an organism .

Energy is converted inside the cell for us to use, the energy amount has to be balanced:

• Too much energy conversion = obesity

• Too little energy conversion = malnutrition

3) All living things Respond to the Environment!

Stimulus:

Anything that causes a response in an organism

Response:

An organism’s reaction to a stimulus

4) Grow and Develop

• Larger structure and change of structure (hair, muscle, bone structure)

• Changing of body shape

5)  Reproduce

• All living things come from other living things

• Reproduction does not mean an individual organism will survive, but the survival of the species

6) Adapt to their Environment

Adaptation:

Physical or behavioural characteristic of a species that increases the species’ chances of survival in a particular environment

Structure And Function

All Organisms need to do certain things to stay alive

• Ex. Predators hunt for food, plants exchange gases, coral reefs absorb nutrients, etc.

• As such, through evolution organisms develop different ways of doing these tasks

Structure:

Parts of an organism that perform specific tasks to survive

Function:

Purpose or task

Different Structures for Similar Functions

• But different plants and animals have developed different structures for doing similar functions

• Example: Using light to respond to the environment

  • Human – Camera eye

  • Insects – Compound eye

  • Amoeba – Phototaxis

CHECKPOINT 1

The Microscope

Without a microscope our eyesight can only see clear, defined images of things that are 0.1 mm or larger

• This means we cannot see any microorganisms that could make us sick!

• This created a few myths in the past, particularly that germs do not exist because we can not see them!

Micro-organisms were first discovered by Anton Van Leeuwenhoek.

• Anton used lenses to look at pond water he was one of the first to essentially find microbial life

• Anton also used lenses to look at blood samples

• He made an object appear larger than it’s actual size, and termed it magnified.

Today’s Microscopes:

• 2 General Types Used in Science Research

  • Compound Light Microscope (up to 2000 X magnification)

  • Electron Microscope (up to 2, 000, 000 X magnification)

Total Magnification :

Two lenses provide the total magnification. The ocular lens (usually 10x) multiplied by the magnification lens (4x, 10x, or 40x) results in the total magnification.

Field of View :

The entire area that can be seen when you look through a microscope

Diameter of Field:

The diameter of the field of view, it's the distance between one side of the lens to another. Diameter of field depends on magnification!!

Lets say at 10x magnification (AKA ocular lens only) your diameter of field is 20mm:

At Low power the objective lens is 4x magnification. So the diameter of field is 4 times smaller :

Diameter of Field / Objective lens magnification

20mm / 4 = 5mm

At Medium power the objective lens is 10x magnification. So the diameter of field is 10 times smaller :

Diameter of Field / Objective lens magnification 

20mm / 10 = 2mm

At High power the objective lens is 40x magnification. So the diameter of field is 40 times smaller :

Diameter of Field / Objective lens magnification 

20mm / 40 = 0.5mm

Microscope Handout

Microscope Mini Lab

How to draw a diagram

Magnified "Small Worlds"

The Cell Is the Basic Unit of Life

• All living things are composed of one or more cells

• Cells are the basic units of structure & function in all organisms

• Cells with similar structure & function are organized into tissues

• Tissues work together for a common purpose to form organs

• A group of organs that work together for a common purpose to keep you alive is called an organ system!

• Cells < tissue < organ < organ system < organism

Cell Function

• Cells need a constant supply of materials like oxygen, carbon dioxide (plant cells), water, nutrients

• Cells needs to get rid of waste products (oxygen is a waste product in plant cells!)

• Cells must control materials going into and out of the cell. Nutrients go into the cell, wastes come out.

Looking at Cells

There are certain factors that can affect what you are able to see in the amount of detail when looking inside a microscope:

• Type of microscope

• Power of the lens

• Quality of the prepared slides

CHECKPOINT 2

Cell Structures

Organelles:

Inside the cell, there are structures that have particular functions to keep the cell alive

• Some organelles may be found in both plants and animals

• Some organelles are found in only plant cells or only in animal cells

• Why the variety of organelles? Depends on the purpose of the cell (Ex. Muscle cell vs. leaf cell)

 Organelles

Nucleus:

The command center of the cell

• Controls the cells activities

• Holds the DNA of the cell

• Directs all cellular activities such as movement, growth, and other life functions

• In both plants and animal cells

Mitochondria:

The powerhouse of the cell

• Chemical reactions occur that convert energy into useable forms

• In both plant cells & animal cells

Ribosome:

The factories of the cell

• Use RNA to build and create protiens and enzymes for use in our body

Cell membrane:

Controllable gateway in and out of the cell

• Surrounds & protects the contents of the cell

• Looks like a thick line around the cell

• Lets needed materials in & waste materials out

• In both plant cells & animal cells

• It has the ability to expand and contract based on how much water is in the cell

Vacuoles:

The storage room of the cell

• Membrane bound sac acting as a storage space for excess food & wastes

• Clear, liquid filled space in cytoplasm

• Plants generally have 1 big vacuole, animal cells generally have many small vacuoles

Cytoplasm:

The Kitchen of the cell

• Covers everything inside the cell except the nucleus

• Contains nutrients required by the cell

• Distributes material to different parts of the cell

• Found in both plant cells & animal cells

Lysosome:

The trash can of the cell

• break down worn out parts of the cell

• depending on the type of cell are used to kill bacteria or viruses

STRUCTURES ONLY FOUND IN PLANT CELLS

Cell Wall:

The frame of the cell, it is surrounds the cell membrane.

• Found in Plant cells NOT in animal cells

• A rigid frame-like covering that surrounds the cell membrane it does NOT expand or contract (unlike the cell membrane)

• Provides structural support for the cell

Chloroplasts:

The solar panels of the cell

• Structures in which photosynthesis takes place

• Greenish structures found only in plant cells

Organisms Can Be Single-Celled or Multi-celled

Unicellular:

Made of just one cell

Micro-organisms :

Very small, generally unicellular organisms that can be seen only through a microscope

• Unicellular organisms :developed specialized structures to perform functions such as eating, moving, reproducing, excreting and reacting to stimuli. (Bacteria, amoebas, paramecium)

Amoeba

• Lives in water, Moves around using pseudopodia

• Foot-like projections. ‘False feet’

• A pseudopod is extended and the cytoplasm fills it. Moves very slow

• Also uses the pseudopodia to eat by surrounding their food (algae, bacteria, plant cells) to create a vacuole

Paramecium

• Moves very fast in the fresh water, covered in cilia to move

• Hair like structures that move back & forth

• Cilia also used to capture food (algae) by channeling food to an oral groove

• Forms a food vacuole to be digested

Multicellular:

Made of  2 or more cells

• Multi-cellular organisms: rely on many very specialized cells to perform functions such as to eat, to move, to reproduce, all the cells interact with one another.

  • Example. Multicellular organisms that eat use cells for digestion, cells for absorption, cells for carrying nutrients throughout body, cells for the muscle to move.

Cells in Multicellular Organisms

Specialized cells:

Cells that have specific structures that help them to perform particular functions

• Specialization means that the cells of a multicellular organism must work together to support their own lives, as well as the life of the whole individual.

For example:

• Red blood cells are small, pliable cells that have no nucleus and are specialized for carrying oxygen to all the cells of the body.

• Do NOT reproduce the same way as other cells

• How do RBC’s reproduce?

• Bones in the skeletal system have marrow which produces red blood cells.

Animal Tissue

All cells in humans and animals can be categorized in four different tissue type

Each organ is made up of different combinations of these 4 types of tissues:

1. Nervous tissue (Sensory)

• Nerves

• Sensory cells

2. Muscle tissue (Movement)

• Smooth muscle

• Skeletal muscle

• Cardiac muscle

3. Connective tissue (Support and connect)

• Blood

• Fat

• Tendon

• Bone

• Cartilage

4. Epithelial tissue (blanket)

• Skin

• Covers organs as well

• Lining of organs

CHECKPOINT 3

Tissue in Plants

Plant cells are also organized into tissues, but plants have 3 tissue types:

1) Ground tissues - (make sugar)

• Cells inside a plant containing chlorophyll that manufacture sugars

• Cells that store glucose, and resins

2) Epidermis Tissues - (Protect plant)

• Cells that line outside of a plant for water proofing (found in leaves)

• Cells that form outside layer of plants (hairs, thorns, stomata)

3) Vascular tissues - (network for water and sugar)

• Xylem tissue (water tubes) - Layer(s) of xylem create tree rings on the inside of plants, this tissue allows water to travel from the roots into all parts of a plant.

• Phloem tissue (sugar tubes) - A layer of phloem tissue surrounds a plant just underneath the bark, it connects leaves to the rest of a plant, it transports sugar (glucose) to all parts of a plant.

Organs in Plants

Tissues are organized into the 3 organs that make up plants:

1. Leaves

2. Roots

3. Stems 

Leaves (A plant’s food producing organs)

• Where photosynthesis takes place

• Contains chloroplasts which are thin, allowing a large amount of light in

• Contains stomata which are tiny opening that allow air to enter the leaf

• Spaces between leaf cells allow the air to flow and the guard cells open and close the stomata

Transpiration:

The loss of water in a plant which happens through the release of water vapour from a plant

• Not a problem unless the plant loses too much water and doesn’t replace it by the roots

• Movement of water throughout the plant happens because of the differences in pressure - high pressure in the root hairs to lower pressure in the leaves

Root system (A PLANT’S NUTRIENT COLLECTING ORGAN)

• If the soil water concentration is greater than root water concentration, water will flow inside of the root hairs, this is done by osmosis!

• Water travels from cell to cell until it reaches the xylem tissue (think tree rings)

• The xylem tissue move the water up the plant by a build up of high water pressure (NOT OSMOSIS!) forcing water up the xylem tissues into stems and leafs

How Substances Move Into & Out of Cells

Diffusion:

Movement of particles of a substance from an area of higher concentration to an area of lower concentration

• It’s a balancing out process of the particles where no energy required

Osmosis:

Special kind of diffusion, it is the diffusion of water particles through a selectively permeable membrane

• Water particles are small enough to diffuse through the cell membrane with ease, depending on the concentration gradient (L to H)

• Osmosis is vital to the survival and health of cells

Selectively permeable:

A membrane with very small openings that allow particles of some substances, but not others, to pass through. (Based on size)

• A permeable membrane allows all materials to go in & out

• An impermeable membrane does not allow anything in or out.

Diffusion & the Cell Membrane

Particles of many substances move in & out of cells by diffusion

• However, the cell membrane acts like a filter with its tiny openings, allowing some particles to go through if they are small enough (I.e. semi-permeable!)

Three Types of Water Solutions

Isotonic solution:

Equal concentration of solutes on each side of semi-permeable membrane

Hypertonic Solution:

Solution with high concentration of solutes (very concentrated)

• Water leaves the cell, and it shrivels

• Potentially fatal to plant

Hypotonic Solution:

Solution with the lower concentration of solutes

• Water enters the cell, and the cell swells

• Potentially fatal to plant

• Cells need an optimal amount of water concentration. There needs to be a balance inside & outside of the cell. If too much water enters and/or leaves the cell, the cell may die

CHECKPOINT 4

Onion Cell Lab

How to draw cells

Rubrics

Super Fun Section!

Unit Review