2.1.1 Cell Structure

Question 1

Maximum resolution of light microscope

Answer 1

0.2 µm

Question 2

Maximum resolution of TEM

Answer 2

0.0002 µm

Question 3

Maximum resolution of SEM

Answer 3

0.002 µm

Question 4

Maximum magnification of light microscope

Answer 4

x1500

Question 5

Maximum magnification of TEM

Answer 5

x1,000,000

Question 6

Maximum magnification of SEM

Answer 6

x500,000

Question 7

How do TEM microscopes work?

Answer 7

They use electromagnets to focus a beam of electrons onto a specimen. Denser parts of the specimen absorb more electrons, so appear darker.

Question 8

How do SEM microscopes work?

Answer 8

They scan a beam of electrons across the specimen, knocking electrons off it which are gathered in a CRT to form an image.

Question 9

TEM 2D or 3D?

Answer 9

2D

Question 10

SEM 2D or 3D?

Answer 10

3D

Question 11

Disadvantages of Electron Microscopy?

Answer 11

No colour, specimen has to be dead due to vacuum and staining.

Question 12

What is resolution?

Answer 12

How detailed the image, how well a microscope distinguishes between two points that are close together.

Question 13

What is magnification?

Answer 13

How much bigger the image is than the specimen.

Question 14

Magnification formula

Answer 14

Magnification = Image Size/Actual Size

Question 15

What stains are used, and how does it help? (Light microscopy)

Answer 15

Dyes are used and the dye is taken up more by certain components than others. This creates contrast. Different dyes for different components/organelles.

Question 16

What stains are used, and how does it help? (Electron microscopy)

Answer 16

Heavy metals are used and these scatter electrons, creating contrast.

Question 17

Structure of Nucleolus

Answer 17

Small spherical body in nucleoplasm, has no membrane, made of RNA.

Question 18

Function of Nucleolus

Answer 18

Manufactures rRNA and assembles ribosomes.

Question 19

Structure of Nucleus

Answer 19

Circular organelle surrounded by nuclear envelope. Nuclear envelope has pores called nuclear pores.

Question 20

Function of Nucleus

Answer 20

Control centre of the cell. Stores genetic material. Provides instructions for protein synthesis.

Question 21

Structure of Rough ER

Answer 21

System of membranes continuous with nuclear envelope. Coated with ribosomes.

Question 22

Function of Rough ER

Answer 22

Produce and transport proteins and glycoproteins within the cell.

Question 23

Structure of Smooth ER

Answer 23

System of membranes continuous with nuclear membrane.

Question 24

Function of Smooth ER

Answer 24

Synthesis/storage/transport of lipids and carbohydrates. Synthesis of cholesterol.

Question 25

Structure of Golgi Apparatus

Answer 25

Stack of membrane-bound flattened sacs.

Question 26

Function of Golgi Apparatus

Answer 26

Modify and package proteins into vesicles.

Question 27

Structure of Mitochondria

Answer 27

Spherical, rod shaped, or branched. Double membrane, inner folded up into cristae to increase surface area.

Question 28

Function of Mitochondria

Answer 28

Site of aerobic respiration (ATP production).

Question 29

Structure of Chloroplasts

Answer 29

Large organelles, surrounded by envelope. Inner membrane continuous with thylakoids.

Question 30

Function of Chloroplasts

Answer 30

Site of photosynthesis.