Cell Structure - Harder

Question 1

What does the objective lens do?

Answer 1

Focuses light and increases magnification.

Question 2

What does the eyepiece lens do?

Answer 2

Increases magnification.

Question 3

What does the light source do?

Answer 3

Shines light through a specimen so it can be seen clearer.

Question 4

What is the role of an eyepiece graticule?

Answer 4

In eyepiece, used to measure the size of an object viewed under a microscope.
Has to be calibrated.
100 divisions with no scale.

Question 5

What is the role of a stage micrometer?

Answer 5

• Used to calibrate eyepiece graticule.
• 1mm with 100 divisions - each division = 10 micrometers.
• Put in microscope as if it was slide.

Question 6

Why is the cover slip lowered at an angle onto a slide?

Answer 6

To prevent bubbles.

Question 7

What is differential staining?

Answer 7

• Using multiple stains.
• Each stain binds to different structures.
• Allows separate structures to be identified.

Question 8

Advantages of staining?

Answer 8

Increases contrast.

Can differentiate between different cells/parts of cell.

Question 9

Advantages of light microscopes?

Answer 9

• Cheap.
• Easy to use.
• Can observe living organisms.

Question 10

Describe how a laser scanning confocal microscope works.

Answer 10

• Specimen treated with fluorescent dye.
• Laser causes components labelled with dye to reflect.

Question 11

Advantages of laser scanning confocal microscope.

Answer 11

• High resolution due to the fact laser beam has small wavelength.
• Non invasive.
• Can view objects inside cells.

Question 12

Structure of the nucleus

Answer 12

• Has membrane with pores to allow molecules in and out of nucleus.
• Stores cell’s DNA.

Question 13

What is chromatin?

Answer 13

DNA + histones

Question 14

Where are ribosomes produced?

Answer 14

Nucleolus

Question 15

SER function

Answer 15

Synthesis of lipids

Question 16

RER function

Answer 16

Protein synthesis for proteins to be outside of cell.

Question 17

Golgi function

Answer 17

Stores, modifies and packages proteins.

Question 18

Lysosome function

Answer 18

Contains hydrolysing enzymes

Question 19

Mitochondria function

Answer 19

Site of aerobic respiration, where ATP production occurs.

Question 20

Cytoplasm function

Answer 20

Site of chemical reactions in cell

Question 21

Plasma membrane function

Answer 21

Controls what substances enter/exit cell

Question 22

Centrioles function

Answer 22

• Assemble microtubules in spindles for mitosis
• Not in plant cells

Question 23

Components in plant cell, not animal

Answer 23

Chloroplasts
Permanent Vacuole
Cell wall

Question 24

Chloroplast function

Answer 24

Site of photosynthesis

Question 25

Vacuole function

Answer 25

Contains cell sap to help support the cell.

Question 26

Cell wall function

Answer 26

- Made of cellulose. - Supports and maintains shape of cell.

Question 27

Microfilaments function

Answer 27

- Cell movement - Contraction during cytokinesis

Question 28

Microtubules function

Answer 28

- Provide tracks for movement of organelles. - Form spindle fibres.

Question 29

Intermediate fibres function

Answer 29

Give mechanical strength to cells

Question 30

What is prokaryote cell wall made of?

Answer 30

Peptidoglycan

Question 31

What is yeast cell wall made of?

Answer 31

Chitin

Question 32

Microtubules in flagella

Answer 32

Contract to make flagellum move. | In 9+2 formation (9 on outside, 2 in middle)

Question 33

What type of ribosomes are in bacteria vs eukaryotes?

Answer 33

- 70S in bacteria - 80S in eukaryotes

Question 34

Which eukaryotic organelle is not membrane bound?

Answer 34

Ribosome

Question 35

How can microtubules be prevented from functioning?

Answer 35

Respiratory inhibitor

Question 36

Light microscope mag + resolution

Answer 36

x 1500 | 200 nm

Question 37

TEM mag + resolution

Answer 37

- x 500,000 - 0.2nm

Question 38

SEM mag + resolution

Answer 38

x 100,000 | 0.2nm

Question 39

Describe endosymbiotic theory

Answer 39

Mitochondria and chloroplasts found in eukaryotic cells represent formerly free-living bacteria that were absorbed into a larger cell.

Question 40

Evidence for endosymbiotic theory

Answer 40

- Mitochondria contain ribosomes that are smaller than those found in the cell cytoplasm. - Mitochondria are a similar size to bacteria. - Chloroplasts have their own circular DNA.

Question 41

What is cristae?

Answer 41

Inner membrane of mitochondrion folded to form cristae.

Question 42

Describe the roles of the cytoskeleton.

Answer 42

- Cell support and stability - Movement of flagella/cilia - Movement of ribosomes

Question 43

Define cell theory

Answer 43

- All living organisms are composed of cells - Cells are the smallest components of life - Cells arise from pre-existing cells - they cannot spontaneously generate

Question 44

Define magnification

Answer 44

The number of times larger the image appears compared to the actual object

Question 45

Define resolution

Answer 45

The smallest distance a microscope is able to distinguish between two separate points