Hinkins' Revision Sheet 2

Question 1

Define magnification.

Answer 1

The number of times bigger an image is than the object.

Question 2

Define resolution.

Answer 2

The ability to distinguish two close together objects as separate objects.
The detail that can be seen.

Question 3

What is staining?

Answer 3

Staining is done to improve contrast in a preparation

Eg it can allow you to see specific organelles.

Question 4

Outline light microscopes.

Answer 4

Uses light as its radiation.
Maximum magnification = 1500x
Maximum resolution = 200nm

Question 5

Advantages of light microscopes.

Answer 5

Can view live specimen
In colour
Light focused by glass lenses
No vaccum
Unlikely to distort sample / introduce artefacts.

Question 6

Outline electron microscope.

Answer 6

Uses electron beam as its radiation.
Maximum magnification 500,000x
Maximum resolution 0.1nm

Question 7

Disadvantages of electron microscope?

Answer 7

Can only view dead specimen
In black and white
Sample must be in a vacuum
Complex slide preparation (more likely to distort sample / introduce artefacts)

Question 8

Outline transmission electron microscope.

Answer 8

Electrons fired at a very thin section of sample. 
Electrons that pass through the sample are detected on a screen behind the sample.
2D image (v high magnification and resolution).

Question 9

Outline scanning electron microscope.

Answer 9

Electrons bounce off a sample’s surface and hit detector.

Allows a 3D image (but slightly lower magnification and resolution than TEM).

Question 10

How to calculate magnification?

Answer 10

Magnification = image / actual size

Question 11

How to calculate actual size?

Answer 11

Actual size = magnification / image

Question 12

How to calculate image size?

Answer 12

Image size = actual size x magnification

Question 13

How to convert nm to mm?

Answer 13

Times image size by 1,000,000

Question 14

How to convert ym to mm?

Answer 14

Times image size by 1000

Question 15

Outline the nucleus.

Answer 15

Large, membrane bound organelle that contains genetic material in chromosomes.

Question 16

What is the nucleolus?

Answer 16

Dark staining region of the nucleus. Associated with the formation of ribosomes and ribosomal RNA.

Question 17

What is the nuclear envelope?

Answer 17

Double membrane around the nucleus. Contains nuclear pores so that mRNA can leave the nucleus.

Question 18

What is a ribosome?

Answer 18

The organelle where protein synthesis takes place.

Question 19

What is the RER?

Answer 19

Transports proteins made in ribosomes on its surface.

Question 20

What is the SER?

Answer 20

Involved in lipid metabolism.

Question 21

What is the Golgi apparatus?

Answer 21

Modifies proteins from the RER (eg by adding carbohydrates to them to make glycoproteins) and packages them into vesicles for secretion.

Question 22

What are mitochondria?

Answer 22

Site of ATP production by aerobic respiration. ATP is required for energy.

Question 23

What are lysosomes?

Answer 23

Contains digestive enzymes to break down pathogens and old cells and organelles.

Question 24

What is the plasma membrane?

Answer 24

Separates cell’s contents from outside environment. And controls what enters and leaves the cell.

Question 25

What are chloroplasts?

Answer 25

Plant cell only. Contains chlorophyll - where photosynthesis takes place.

Question 26

What are centrioles?

Answer 26

Animal cell only. Pair of organelles that form spindle fibres to move chromosomes during nuclear division.

Question 27

What are cilia?

Answer 27

Hair-like projections used to move mucus abs substances iced cell surfaces.

Question 28

What are flagella?

Answer 28

Used for cell locomotion (aka undulipodia in eukaryotes).

Question 29

What is plasmodemata.

Answer 29

Strands of cytoplasm that connect adjacent plant cells.

Question 30

How can you tell the Golgi apparatus from the sER?

Answer 30

The Golgi apparatus always has vesicles building off it.

Question 31

The membrane around the outside of the cell must be labelled as the…

Answer 31

Cell surface membrane / plasma membrane.

Question 32

What’s the cytoskeleton?

Answer 32

Th cytoskeleton consists of various protein molecules that give the cell some structure as provide pathways for the movement of vesicles.

Question 33

Outline prokaryotes.

Answer 33

No nucleus. 
Naked DNA is in loops in the nucleoside and not associated with any proteins. 
No membrane bound organelles. 
Small ribosomes (70S). 
Have a peptidoglycan cell wall.

Question 34

Outline eukaryotes.

Answer 34

Membrane bound nucleus.
DNA in the find if linear molecules wrapped around histone proteins. 
Membrane bound organelles present.
Larger ribosomes (80S). 
No cell wall.

Question 35

Example of prokaryote?

Answer 35

Bacteria

Question 36

Example of eukaryote?

Answer 36

Plant, animal, fungus

Question 37

How are proteins processed? (6)

Answer 37

1. Proteins synthesised in ribosomes on RER.
2. Proteins move to Golgi apparatus in vesicles.
3. Golgi modifies proteins and packages them into vesicles.
4. Vesicles containing modified protein are carried to cell surface membrane.
5. Vesicles fused with cell surface membrane.
6. Modified proteins released from cell by exocytosis.

Question 38

What is a tissue?

Answer 38

A collection of cells of similar types working together to perform a specific function.

Question 39

What is an organ?

Answer 39

A collection of similar tissues working itgether to perform a specific function.

Question 40

What is compartmentalisation?

Answer 40

Internal membranes surround organelles and vesicles within the cell bringing about different environmental conditions within the same cell.

This allows the conditions inside each of these organelles to be optimised to the function of that organelle (eg perfect pH and ion conc. inside the ribosomes it make proteins).