Cell structure Flashcards
Light microscope
wavelength= 400nm, resolution= 200nm
cheap and easy to use
natural colour
magnification= x1500
fluorescent dye stain, coloured chemicals
living and dead specimens
Electron microscope
Electron beam= 0.4nm, resolution= 0.2nm
magnification= x10000
metal particles as stain
dead specimens as they are put through vacuum and stain kills
black and white, difficult, very expensive
SEM (scanning EM)
resolution= 3-10nm
magnification= x100000
3D images, bounces off surface
TEM (transmission)
resolution= 0.2nm
magnification= x500000
2D image, transmitted through
What happens in staining in light microscopy
Fixing- formaldehyde, used to preserve specimens
Sectioning- dehydrated with alcohols and placed in wax or resin, then sliced thinly with a knife (allow light through)
Staining- using coloured chemicals or dyes to be able to see specimens, methylne blue, acetin ocein
Mounting- secured to microscope slide and cover slip placed on top
Differential staining- distinguish between two types of organisms/ different organelles
Organelle
Structure in a cell that has a specialised function
Organelles working together is called division of labour
Different organelles have different functions
Ultrastructure
Detailed structure of the internal components of cells as revealed by electron microscope
Ultrastructure of an animal cell
Golgi apparatus
Cell surface membrane
lysosomes
smooth ER
rough ER
mitochondria
nucleolus
nucleus
microvilli
ribosome
nuclear pores
nuclear envelope
centrioles
Ultrastructure of plant cells
Smooth ER
vesicle
permanent vacuole
nucleus
nucleolus
golgi apparatus
mitochondrion
chloroplast
cell surface membrane
cellulose cell wall
Rough ER
ribosomes
Function of smooth ER
Makes lipids
Cells that make steroid hormones have lots of ER
Function of ribosome
Makes proteins
Function of rough ER
Transports proteins made by attached ribosomes
Function of Golgi apparatus
Modifies and packages proteins, makes secretory vesicles and lysosomes
Function of lysosomes
Contains enzymes for destroying worn out organelles and food particles
Function of nucleus
Controls activities of the cell, stores and protects DNA
Function of nucleolus
Makes ribosomes and RNA
Function of mitochondrion
Aerobic respiration- makes ATP
Folds are called cristae
Middle is called the matrix
Function of chloroplasts
Photosynthesis
Contains inner membranes called thylakoids which are rich in photosynthesis
Function of centrioles
Forms spindle fibers during cell division
How to use an eyepiece and stage micrometer?
Line up the eyepiece graticule and the stage micrometer
Each division of the stage micrometer is a specific value
Work out size of 1 division on the eyepiece graticule
Calculating magnification
Magnification= image size/ actual size
I mm= 1000 micrometers
IAM triangle
Function of cytoskeleton
Network of protein fibres within the cell
It gives structure and shape to the cell, moves organelles around the inside of the cell, enables of movement of whole cell
Function of flagella and cilia
Move cells and move liquids across the surface of the cell
How organelles work together to make and secrete proteins?
1.) mRNA copy of the instructions for insulin is made in the nucleus
2.) mRNA leaves the nucleus through nuclear pore
3.) mRNA attaches to ribosome on the ER, reads the instructions to assemble the protein
4.) insulin molecules are pinched off in vesicles and travel towards Golgi apparatus
5.) vesicles fuses with Golgi apparatus
6.) Golgi apparatus processes and packages insulin molecules ready for release
7.) Packaged insulin molecules are pinched off in vesicles from golgi apparatus and move towards cell surface membrane
8.) vesicles fuses with cell surface membrane
9.) cell surface membrane opens to release insulin molecules outside
ultrastructure of a prokaryotic cell
Flagella
pilus
nucleoid
ribosomes
plasmid
capsule
cell wall
plasma membrane
mesosome
key features prokaryotic cells
No true nucleus
no membrane bound organelles
cell wall made of peptidoglycan
ribosomes are smaller
flagella for locomotion
smaller cells
Organelles shared by eukaryotes and prokaryotes
Cell wall, ribosomes, flagella and cell surface membrane
