Notes Term 3

Notes Term 3

What is it?

Are these two structures the same? What differences do you notice?The images above are of cells.

Plant CellAnimal CellSimple description: Animal CellSoft/permeable cell wallRound in shapeRed, purple, or pink in color

Simple description: Plant CellRigid (hard) cell wallStraight edges, almost rectangular in shapeGreen or blue in color

The CellThe cell is the basic unit of life.Cells can feed themselves, grow and reproduce.Some cells are even able to move.In nature there are two types of cells; animal cells and plant cells.Both of these structures share many of the same components and have similar functions. Plant and animal cells have the following components in common;Cell membrane NucleusCytoplasmVacuolesPlants cells also contain a rigid cell wall and chloroplast.Cell membraneSurrounds and contains the cell.Controls what enters and exits the cell.This layer is very thin and soft.

Nucleus Most important part of the cellIt controls all cell functions, like the brainIt also controls the cells ability to divide.It contains genes and chromosomes as well as DNA.

CytoplasmGel that is found within a cell.Facilitates chemical reactions.Transports food and oxygen to different parts of the cell.

VacuoleLiquid filled cavity within the cell.It is used to store food, minerals, salts and proteins.It contains pigments in plant cells

Rigid Cell Wall (plants only)The rigid cell wall gives plants their structure. This is what keeps plants firm and upright.It also protects the cells, like skin for animals and humans.

Chloroplast (plants only)Chloroplasts contain the chlorophyll.Chlorophyll plays a vital role in photosynthesis.This chemical absorbs sunlight which allows plants to produce food.

In order to survive all living things must live in an area that will encourage life.All species that live in the same area will have similar characteristics and similar needs. The basic characteristics of all living things are:Respiration (breathing)Nutrition (eating)GrowthIndependent MovementReactions to changes in their areasAdaptation (Changing to meet needs)ReproductionTechnological and Non-Technological SystemsSystem: is a set of parts, mechanisms, devices, machines, cellular components that are put together to accomplish a specific task.Ex: Cells, digestive system, reproductive system, alarm clocks, factory assembly lines.Systems could be natural or technological (man made).Every system has a specific function for which it is designed.For example: A bicycle is designed to support a persons weight and allow them to move forward.What is the function of the following images?

Components, Inputs and Outputs Components: Anything that plays a role in the functioning of a system. Ex: gears, machines, wires, cytoplasm, chloroplastInput: Anything that enters a system which is necessary for a system to function properly.Ex: gasoline in a car, food and oxygen for living things.

Transformation process: the work that the system does when it is functioning properly.Ex: an engine burns gas in order to move the car forward.In this process the system uses the energy it gets from the inputs.Output: Anything that the system does not use and thus exits the system.Ex: Animals and humans releasing waste.Therefore, a system consists of components, inputs, outputs, and transformation processes.Identify the inputs and outputs

OOOOOIIIIEnergy transformationEnergy can be found in many different forms; electrical, chemical, mechanical, etc.Every system needs some form of energy to work.It is very important to remember that energy is never created or lost, it is only transformed.

This means that whatever energy goes into a system, will come out of the system in different forms

Some examples of energy transformation: Electrical into heat: stoveChemical into mechanic: car

Exchanges between the cell and its environmentThe cell membrane is responsible for allowing materials to enter or exit the cell.It is vital for the survival of the cell that inputs (oxygen, nutrients) are able to enter and outputs exit as quickly as possible.There are two mechanisms that substances cross through the cell membrane. The two mechanisms are:DiffusionOsmosis

DiffusionDiffusion: movement of particles from an area of higher concentration to an area of lower concentration, until an equilibrium is reached.Concentration: is how much a substance is mixed with another substance.Equilibrium: is when the concentration on the inside and the outside of the cell are equal.OsmosisOsmosis consists of water passing through the cell membrane.Osmosis: water moves from an area of lower solute to an area of higher solute, until an equilibrium is reached. See notes from term one on solute and solvent.The MicroscopeThe Microscope has one basic function. To make very small objects visible to the human eye.The first microscope is believed to have been invented in the Netherlands in the 1590s.By the 1660s the microscope was in use in many major European nations.

The microscope has several important components which you must know.The eyepiece: used be the eye to view the object.Objective lenses: enlarge the object being observed. (Different lenses will magnify the object 4,10, 40 times)The Stage: where the object is placedCondenser: Concentrates light into the objectLight source: sends light into the object so that it may be viewed.The pointer: shows the exact point the user is observing.Coarse-focus: always used first to focus your imageFine-focus: used second to focus to object more sharply.

Cellular Components Visible Under a MicroscopeThere are several components of cells that are visible under a microscope.Unfortunately with a regular microscope not all components of a cell are visible.The following components are visible under a microscopeCell MembraneNucleus CytoplasmVacuole Chloroplasts (plants only)

Basic Mechanical FunctionsAs mentioned above the basic function of a microscope is to magnify objects so that they can be seen by the human eye.Within the microscope each component plays an essential role.Each component in the microscope works together to fulfill its function.Different parts working together is called mechanical function.

BaseLightSourceCondenserStageObjectiveLensesFineFocusCoarseFocusEyepieceLinks and Guiding ControlsLinks: allows parts to be assembled or connected to one another.There are 4 types of linksDirect links: slide placed on the microscope stageIndirect links: screws that hold the stage in placeRemovable links: light sourceFixed links: base of the microscopeGuiding controls: allows one part to direct or guide another along a set path.There are two types of guiding controls.Rotation guiding: turning on an axisEx: objective lenses can be rotatedTranslation guiding: moves in a straight line.Ex: the stage of the microscope can be moved up or down using the coarse focus knob.