🟢7 Cell Structure Flashcards
How many lenses in a compound microscopes
Two lenses
What is an ultrastructure of a cell
Ultrastructure is the detail of a structure as seen using an electron microscope
What are electron microscopes
These miscrosopes use a beam of electrons instead of light.
Two types of electron microscopes
TEM) Transmission electron microsope
-Sends beam of electrons throu a thin section of the specimen. Shows internal structure of the specimen in great detail.
SEM) Scanning electron microscope
-Uses a beam of electrons to provide a surface view of the specimen
What is the protoplasm of a cell
This is all the living parts of a cell
(cytoplasm,nucleus)
What is the cytoplasm
The living material in a cell outside the nucleus
What is the cell wall made of
cellulose
What is cellulose
Its a strong structural carbohydrate (polysaccharide).
Main component in cotton and wool
What is the fluid inside vacuole
Cell sap (solution of salts,sugars and pigments)
Plant cells that are green contain
chloroplasts.
This is where photosynthesis takes place
How high of a magnification can electron microscopes give
They can give magnifications of 250000 or higher
What is the cell membrane composed of
Phospholipids and proteins
How are phospholipids aranged in cell membrane
Arenged into double layers (bilayers)
The phosphates are on the outer side with the lipids in the middle
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Where are proteins located in a cell membrane
They are partially or completely embedded in the phospholipid bilayer
Some are attached and others can move throughout the bilayer
4 Main functions of Cell Membrane
1.Retain cell contents
2.Control what goes in/out
3.Gives some support to the cell
4.Recognise molecules thst can touch them
Why is cell membrane said to be selectively/semi permeable
It allows some molecules in and prevents others
What is the nucleus in relatipn to the cell
Control centre of the cell
What is the nucleus surrounded by?
A double membrane with numerous nuclear pores
what do nuclear pores do for the nucleus?
Allow controlled entry/exit of molecules in/out of the nucleus
What does DNA stand for
Deoxyribonucleic acid
What does the nucleus contain
Strands of DNA which are arranged into structures called chromosomes
how many chromosomes does a human have
46
Define chromatin
name given to chromosomes when they are elongated and not dividing (ie. most of the time)
What are genes and what do they do
They are the structures that inform the cell how to make certain proteins
Control:eye colour, fingers, production of enzymes + much more
