1.3 Cells

Question 1

What is resolution?

Answer 1

The minimum point at which to items appear separate

Question 2

What is an electron microscope?

Answer 2

It has a shorter wavelength of lightIt is focused by electromagnets X,1,000,000 mag 0.1nm resolve

Question 3

What is the transmission microscope?

Answer 3

Through specimen0.1nmStained piece- B&W imageThin Artefacts2D imageVacuum

Question 4

What is a surface microscope?

Answer 4

Across specimene- scattered by contours 20nm resolve3D imageLow resolving power

Question 5

What are the conditions for cell fractionation?

Answer 5

Cold- reduce enzyme activityIsotonic- prevent osmotic gain/lossBuffeted- same pH

Question 6

What is the process of cell fractionation?

Answer 6

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

Question 7

What is the features of the nucleus?

Answer 7

Pores allow molecules outNuclear envelope is a double membrane continuous with the rough endoplasmic reticulumChromatin is diffuse DNA

Question 8

What are the features of the mitochondria?

Answer 8

Double membrane controls the exit & entry of materialThe Christie internal extensions of the membrane which increase surface area for attachment of enzymes

Question 9

What are the features of the endoplasmic reticulum?

Answer 9

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

Question 10

What are the features of the Golgi body?

Answer 10

Flattened sacks with cristaeThe add carbohydrates to form glycoproteinsThey produce secretory enzymes

Question 11

What are the features of lysosomes?

Answer 11

Golgi vessels containing enzymes to destroy cells and pathogenic material

Question 12

What are the features of ribosomes?

Answer 12

80s- eukaryotic 25nm70s prokaryotic <25nmSynthesise proteins

Question 13

What are lipids?

Answer 13

A polymer which varies but always contains CHO and insoluble in water

Question 14

Where are lipid used?

Answer 14

In the plasma membraneAs an energy storeWaterproofInstallation Protection of organs and

Question 15

What is the test for lipids?

Answer 15

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

Question 16

What is diffusion?

Answer 16

Movement of molecules material on area of high concentration to low concentration down a concentration gradient passively

Question 17

What is the rate of diffusion?

Answer 17

Surface Area. X Concentration gradient———————————————Diffusion pathways

Question 18

What is facilitated diffusion?

Answer 18

Using protein molecules in the membrane as channel which is specific to the molecule

Question 19

What is osmosis?

Answer 19

The movement of water from an area of high water potential to low water potential passively

Question 20

What is active transport?

Answer 20

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

Question 21

Describe active transport

Answer 21

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.

Question 22

How do you calculate magnification?

Answer 22

Image/Actual size

Question 23

Describe absorption

Answer 23

Microvilli in the small intestineIncrease the surface area Thin to decrease diffusion pathwaysupplied with blood vessels to move substrates