1.3 Cells Flashcards
What is resolution?
The minimum point at which to items appear separate
What is an electron microscope?
It has a shorter wavelength of lightIt is focused by electromagnets X,1,000,000 mag 0.1nm resolve
What is the transmission microscope?
Through specimen0.1nmStained piece- B&W imageThin Artefacts2D imageVacuum
What is a surface microscope?
Across specimene- scattered by contours 20nm resolve3D imageLow resolving power
What are the conditions for cell fractionation?
Cold- reduce enzyme activityIsotonic- prevent osmotic gain/lossBuffeted- same pH
What is the process of cell fractionation?
1) cell are broken- homogenised2) plant walls are filtered3) centrifuged 1000xg/10m- dense nuclei sinks4) centrifuged 10,000xg/30m- mitochondria and chloroplasts sinks5)centrifuged 100,000xg/1 hour- endoplasmic reticulum and Golgi sink6) centrifuged 300,000xg/3hours- ribosomes and cytoplasm seperated
What is the features of the nucleus?
Pores allow molecules outNuclear envelope is a double membrane continuous with the rough endoplasmic reticulumChromatin is diffuse DNA
What are the features of the mitochondria?
Double membrane controls the exit & entry of materialThe Christie internal extensions of the membrane which increase surface area for attachment of enzymes
What are the features of the endoplasmic reticulum?
RER have ribosomes on surface to increase the surface area for protein synthesisRER provide a pathway for transport of proteinsSER are tubular without the ribosomes to synthesises lipids and carbohydrates
What are the features of the Golgi body?
Flattened sacks with cristaeThe add carbohydrates to form glycoproteinsThey produce secretory enzymes
What are the features of lysosomes?
Golgi vessels containing enzymes to destroy cells and pathogenic material
What are the features of ribosomes?
80s- eukaryotic 25nm70s prokaryotic <25nmSynthesise proteins
What are lipids?
A polymer which varies but always contains CHO and insoluble in water
Where are lipid used?
In the plasma membraneAs an energy storeWaterproofInstallation Protection of organs and
What is the test for lipids?
2 cm³ of sample and 5 cm³ of ethanol to a TestTubeShake the tube Add 5 cm³ of waterIf it is cloudy white… lipid present
What is diffusion?
Movement of molecules material on area of high concentration to low concentration down a concentration gradient passively
What is the rate of diffusion?
Surface Area. X Concentration gradient———————————————Diffusion pathways
What is facilitated diffusion?
Using protein molecules in the membrane as channel which is specific to the molecule
What is osmosis?
The movement of water from an area of high water potential to low water potential passively
What is active transport?
The movement of molecules or ions into or out of the cell from an area of low concentration to high concentration against a concentration gradient actively
Describe active transport
Carrier protein pumps stand the cell-surface membrane. Molecules attach to receptors on the channel of the protein. ATP binds to the protein causing it to split into ADP and phosphate molecule. The protein molecule changes shape opening into the cell releasing the molecules and ions. Phosphate is released by protein and joins ADP to form ATP.
How do you calculate magnification?
Image/Actual size
Describe absorption
Microvilli in the small intestineIncrease the surface area Thin to decrease diffusion pathwaysupplied with blood vessels to move substrates
