Hinkins' Revision Sheet 2 Flashcards Preview

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Flashcards in Hinkins' Revision Sheet 2 Deck (40)
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1
Q

Define magnification.

A

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

2
Q

Define resolution.

A

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

3
Q

What is staining?

A

Staining is done to improve contrast in a preparation

Eg it can allow you to see specific organelles.

4
Q

Outline light microscopes.

A

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

5
Q

Advantages of light microscopes.

A
Can view live specimen
In colour
Light focused by glass lenses
No vaccum
Unlikely to distort sample / introduce artefacts.
6
Q

Outline electron microscope.

A

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

7
Q

Disadvantages of electron microscope?

A

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)

8
Q

Outline transmission electron microscope.

A
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).
9
Q

Outline scanning electron microscope.

A

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

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

10
Q

How to calculate magnification?

A

Magnification = image / actual size

11
Q

How to calculate actual size?

A

Actual size = magnification / image

12
Q

How to calculate image size?

A

Image size = actual size x magnification

13
Q

How to convert nm to mm?

A

Times image size by 1,000,000

14
Q

How to convert ym to mm?

A

Times image size by 1000

15
Q

Outline the nucleus.

A

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

16
Q

What is the nucleolus?

A

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

17
Q

What is the nuclear envelope?

A

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

18
Q

What is a ribosome?

A

The organelle where protein synthesis takes place.

19
Q

What is the RER?

A

Transports proteins made in ribosomes on its surface.

20
Q

What is the SER?

A

Involved in lipid metabolism.

21
Q

What is the Golgi apparatus?

A

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

22
Q

What are mitochondria?

A

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

23
Q

What are lysosomes?

A

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

24
Q

What is the plasma membrane?

A

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

25
Q

What are chloroplasts?

A

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

26
Q

What are centrioles?

A

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

27
Q

What are cilia?

A

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

28
Q

What are flagella?

A

Used for cell locomotion (aka undulipodia in eukaryotes).

29
Q

What is plasmodemata.

A

Strands of cytoplasm that connect adjacent plant cells.

30
Q

How can you tell the Golgi apparatus from the sER?

A

The Golgi apparatus always has vesicles building off it.

31
Q

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

A

Cell surface membrane / plasma membrane.

32
Q

What’s the cytoskeleton?

A

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

33
Q

Outline prokaryotes.

A
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.
34
Q

Outline eukaryotes.

A
Membrane bound nucleus.
DNA in the find if linear molecules wrapped around histone proteins. 
Membrane bound organelles present.
Larger ribosomes (80S). 
No cell wall.
35
Q

Example of prokaryote?

A

Bacteria

36
Q

Example of eukaryote?

A

Plant, animal, fungus

37
Q

How are proteins processed? (6)

A
  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.
38
Q

What is a tissue?

A

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

39
Q

What is an organ?

A

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

40
Q

What is compartmentalisation?

A

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).