Cell structure

Funcion of cell memrane

* Holds the cell together * Controls what goes in and out of the call * separates the inside of the cell from the environment outside

Function of cytoplasm

* A jelly-like fluid in which organelles are found
* Chemical reactions take place here

Function of ribosome

The site for protien sunthesis in the cell

Function of mithochondria

Site for aerobic respiration

provides energy to the cells

FUntion of a neucleus

Contains genetic materials

Controlls all activities inside the cell

Which cellular components are found in an animal cell?

* Nucleus
* ribosome
* cell membrane
* cytoplasm
* mithochondria

Which are the extra cellular components in a plant cell?

* chloroplast
* permanent vacuole filled with cell sap
* cell wall

What is the function of chloroplast?

Contains green chlorophyll pigment which absorbs light for photosynthesis

What is the funtion of a cell wall and what is it made up of ?

It is made up of cellulose (a polymer of glucose)

which strengths the call and gives extra support defining its shape

What is the function of a permanent vacuole?

Contaims cell sap (a solution of sugars and salts dissolved in water)

Gives cells structure and support

used for storage of certain materials

What kind of cells are procaryotic cells?

Bacterial cells

What are the difference between eukaryotic cells and procaryotic cells?

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* procaryotic cells have small rings of DNA called plasmids
* Procaryotic cells are uni cellular
* eukaryotic cells have mitochondria
* Procaryotic cells are smaller than eukaryotic cells
* procaryotic cells do not have a neucleus

Formula for calculating magnification

Magnification = Image size / actual size

Image size= actual size x magnification

I= am

what does µm stand for?

Micrometer

how many µm (micrometer) is 1 mm?

1mm= 1000µm

How many nm (nano meter) is 1 µm?

1 µm = 1000 nm

cm to mm

1 cm= 10 mm

m to mm

1 m = 1000m

How does a light microscope work?

Light from a mirror (or light source) passes through the spicemen, objective lens, the eyepiece lens, then into our eyes

Advantages of a light microscope compared to an electron microscope

* cheap
* easy to use
* small, so portable
* produce colour images
* can see living spiecemens

disvantages of a light microscope compared to an electron microscope

* relies on light
* has a longer wave length than electrons, so they have a lower resolution than electron microscopes
* lower maximun magnification, so details such as details of sub cellular structures arent often visible.

disvantages of an electron microscope compared to a light microscope

* expensive
* difficult to use and requires specialist training
* image can only be seen in black and white
* large so difficult to transport
* can only view dead spicemens

Advantages of a electron microscope

-Higher resolution

-Higher magnification

An electron microscope has much higher magnification and resolving power than a light microscope.

This means that it can be used to study cells in much finer detail. This has enabled biologists to see and understand many more sub-cellular structures.