1
Q
What did schleiden discover
A
All plants were made of cells
2
Q
What did Schwann discover
A
All animals were made of cells
3
Q
What does the cell theory state
A
- Both plant and animal tissue is composed of cells
- cells are the basic unity of all life
- cells only develop from existing cells
4
Q
What are the four types of sample preparation
A
- Dry mount
- Wet mount
- squash slides
- smear slides
5
Q
Summarise Dry mount
A
-Solid specimens are viewed when been sectioned
-placed on slide with cover slip placed over it
-
6
Q
Summarise Wet mount
A
- Specimens are suspended in a liquid such as water/immersion oil
- Cover slip is placed at an angle
7
Q
Summarise Squash slides
A
- Wet mount is first prepared
- lens tissue gently presses down the cover slip
- Careful not to break the slip when pressing down
8
Q
Summarise Slides
A
- The edge of the slide is used to smear the sample creating a thin even coating on another slide
- cover slip is placed over the sample
9
Q
What sample preparation technique would you use to study: Hair pollen, dust, insect parts, muscle tissue, or plants
A
Dry mount
10
Q
What sample preparation technique would you use to study: aquatic samples
A
Wet mount
11
Q
What sample preparation technique would you use to study: cell division
A
Squash slides
12
Q
What sample preparation technique would you use to study: Cells in blood
A
Smear slides
13
Q
Why would you use staining in light microscopy
A
- normally low contrast as most cells no not absorb a lot of light
- Stains increase contrast in cells as different components of cell take up different stain degrees
- Resolution is limited by wavelength of light
14
Q
How would you prepare a sample for staining
A
- Placed on slide and allowed to air dry
- Heat fixed by passing through flame
- specimen will adhere to the slide and take up the stain
15
Q
Equation for magnification
A
Size of image divided by actual size of object
16
Q
What is resolution
A
How clear the image is
17
Q
What is contrast
A
The shading difference
18
Q
What are the 2 types of electron mircoscopes
A
- Scanning electron microscope
- Transmission electron microscope
19
Q
What magnification can electron microscopes go up to
A
over x500,000
20
Q
How does a Transmission microscope work
A
A beam of electrons is transmitted through a specimen and focused to produce an image
21
Q
How does a Scanning microscope work
A
A beam of electrons is sent across the surface of a specimen and the reflected electrons are collected
22
Q
What is the transmissions resolving power
A
Best resolving power with 0.5nm
23
Q
What is the scanning resolving power
A
resolving power is 3-10nm which isn’t as good but it produces 3D images`
24
Q
Why would you see in more detail with an electron microscope than a light microscope
A
The electron wave length is smaller than a light wavelength therefore giving you a better image
25
What is an artefact
A visible structural detail that isn't supposed to be there
26
What does differential staining do
Helps distinguish between two types of organisms that would otherwise be hard to identify.
27
What is the Gram stain technique used for
To separate bacteria into two groups, Gram positive and Gram negative
28
What will happen to Gram positive bacteria
retain the crystal violet stain and will appear blue or purple under the microscope
29
What will happen to Gram negative bacteria
thinner cell walls therefore lose the stain.
| stained counterstain making them appear red
30
What are Gram positive bacteria susceptible to
Penicillin
31
Why are the microscopy slides brought into school ready-prepared
- Can be harmful
| - long complex process needed to produce high quality sections
32
What is acid fast techniques used for
Differentiate species of Mycobacterium from other bacteria
33
What is a lipid solvent used for in the acid fast technique
Carries a carbolfuchsin dye into the cells being studied
34
What do you do for fixing in microscopy
chemicals like formaldehyde are used to perverse specimens in as near-natural state as possible
35
What do you do for sectioning in microscopy
specimens are hydrated with alcohols and then placed in a mould with wax or resin to form a hard block, then sliced thinly with a micotome
36
What do you do for staining in microscopy
specimens are often treated with multiple stains to show different structures
37
What do you do for mounting in microscopy
The specimens are then secured to a microscope slide and a cover slip placed on top
38
Properties of a Nucleus
- Regulates cellular functions
| - non-bound membrane
39
Properties of a nuclear envelope
Double layered and goes around the nucleus
| Physical barrier between contents of nucleus and cytoplasm
40
What do nuclear pores do
- Make proteins
| - Allows small molecules to diffuse in and out of the nucleus
41
Properties of the Rough ER
- Double membrane that sits next to the nucleus
- contains flattened sacs
- with ribosomes
42
What are the flattened sacs called in the RER
Cisternae
43
What is the RER's function
- Protein production
- synthesis and transport of protein
- alters proteins produced by ribosomes
- packs proteins for targeted destinations around cell
44
Where can ribosomes be found
- Floating in the cytosil or attached to the RER
| - mitochondria or chloroplasts
45
What are ribosomes a site for and what are they made from
They're made of RNA molecules and are a site for protein synthesis
46
What do ribosomes do
They convert smaller amino acid monomers into more complex polymers
47
What does the cell membrane do
- Separates cell from environment
| - controls movement of substances
48
What is the cell membrane made from
Lipids and proteins
49
How much volume of the cell does the mitochondria take up
Up to 25%
50
Is mitochondria found in eukaryotic or prokaryotic cells
Eukaryotic cells
51
What does the mitochondria do
- Creates energy rich molecules
| - ATP synthesis is the enzyme that helps create the energy store
52
Where are chemical reactions stored in the mitochondria
In the membrane
53
Where is the fluid stored in the mitochondria
In the matrix
54
What hormones does mitochondria help build
testosterone and oestrogen
55
Is the mitochondria permeable or impermeable
It's completely impermeable
56
How do mitochondria become bigger
They can combine to get bigger
57
What does the SER do
- Synthesises hormones and lipids
| - detoxifies harmful metabolic waste products
58
Where is the SER found
cells which are apart of the endocrine system
59
What is the Golgi made up of
cistennae
60
What does the Golgi do
- packages up macro molecules IE: proteins and sends them to the rest of the body
- Transports liquids around the cell
61
What do lysosomes do
Like rubbers.
| Break down and kill parts of cells
62
Where is chloroplast found
Plant cells, algi
63
What's chloroplasts function
Takes part in photosynthesis
64
What do chloroplasts do
Absorb sunlight and carries out reaction of photosynthesis
65
What do centrioles take part in
helps in Cellular division
66
Does centrioles take part in meiosis or mitosis
Both of them
67
What is the cellulose cell wall made from
Carbohydrates
68
What does the cellulose cell wall do
Supports the cell
69
Is the cellulose cell wall permeable or not
It's completely permeable
70
What does the cell vacuole contain
Water, sugars which make cell sap
71
What's the cell vacuole used for
- Support the cell
| - storage
72
In order to support the plant does the vacuole need to be turgid or flaccid
Turgid
73
What happens to the vacuole when the plant is turgid and what happens to it when it's flaccid
Turgid: it takes up more of the cell: support
Flaccid: shrinks taking up less of the cell: no support
74
What's the DNA like in a prokaryote cell
DNA is super coiled
75
What's DNA like in a eukaryote cell
Linear
76
What are ribosomes like in a prokaryote cell
Smaller: 70s
77
What are ribosomes like in a eukaryote cell
Bigger more complex: 80s
78
What's the cell wall like in a prokaryote cell
- made of Peptidoglycan
| - complex polymer from amino acids and sugars
79
What's the cell wall like in a eukaryote cell
Not present in animal cells only in plant cells
80
What's the flagella like in a prokaryote cell
thinner in structure
| doesn't have the 9+2 arrangement
81
What's the flagella like in a eukaryote cell
Has the 9+2 arrangement
82
What's the extra chromosomal DNA like in a prokaryote cell
Circular DNA called plasmids
83
What's the extra chromosomal DNA like in a eukaryote cell
only in some organelles ie: chloroplasts and mitochondria
84
What's the correct term for: structure within the cell consisting of micro tubules and micro filaments
Cytokeleton
85
What's a graduated measuring scale placed on the microscope stage called
a stage micrometer
86
What 2 parts of a light microscope magnify the specimen
objective lens
| eyepiece tube
87
What's the dark staining region where ribosomes are made
nucleolus
88
What structure of the cell is only visible with an electron microscope
Ribosomes
89
light microscope and electron microscope imaging advantages
electron microscope: can view small objects in better resolution
light microscope: can view living cells
90
Why would you use methylene blue when looking at a cheek cell
To stain the cells
91
Why do you lower the cover slip gently
To avoid any air bubbles being trapped
92
Why would you set the microscope to the lowest magnification
Get the highest FOV making it easier to locate the specimen
93
How do you achieve good focus on low power using a light microscope
Coarse focus knob
A level Biology Year 1
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