Module 2.1 Cell Structure Flashcards
1
Q
Magnification🔎
A
How much bigger an image appears compared with the original object
2
Q
Resolution
A
The ability to be able to distinguish between 2 points that are very close together
3
Q
Advantages of light microscopes🔬
A
Relatively cheap, easy to use, portable, can study living specimens
4
Q
Max magnification of a light microscope 🔬
A
1500 times
5
Q
Max resolution of a light 🔬
A
200nm
6
Q
How do you calculate total magnification
A
Magnifying power of the objective lens TIMES BY magnifying power of the eyepiece lens
7
Q
Disadvantages of electron microscopes
A
Large, expensive, needs a great deal of skill and training to use, specimens need to be dead
8
Q
Image formed by transmission electron microscopes
A
2D Black and White image
9
Q
Image formed by scanning electron microscope
A
3D Black and White (although false colour can be added)
10
Q
Acetic oncein binds to DNA and stains chromosomes
A
Dark red🌶👹👺💃🏿🎒🦀🍎🍒🍷
11
Q
Name an example of an all purpose stain
A
Methylene blue 💤🐟💦👖👕🐳🐬☄️🎽🚙🛢
12
Q
How would you prepare a specimen?
A
Dehydrate the specimen, embed it in wax (to prevent distortion) and section the specimen
13
Q
Calculations involving magnification formula
A
Magnification = Image DIVIDED BY Actual size
14
Q
Features of a generalised animal cell
A
Ribosomes Mitochondria Nucleolus Nucleus Smooth Endoplasmic Reticulum Plasma membrane Golgi apparatus Lysosomes Nuclear envelope Rough Endoplasmic Reticulum
15
Q
Features of a generalised plant cell 🌱
A
Chloroplast Amyloplast containing starch Golgi apparatus Smooth Endoplasmic Reticulum Ribosomes Nucleolus Nucleus Nuclear envelope Rough Endoplasmic Reticulum Plasma membrane Cell wall Vacuole Mitochondria
16
Q
🌟Describe the stages in the production of extracellular proteins
A
- mRNA copy of the gene is made in the nucleus 〰 (transcription)
- mRNA leaves the nucleus through a nuclear pore
- mRNA attaches to a ribosome (e.g. attached to the rough endoplasmic reticulum). The ribosome reads the instructions to assemble a protein (translation)
- Molecules are “pinched off” in vesicles and travel towards the Golgi apparatus
- Vesicle fuses with the Golgi apparatus
- Golgi apparatus processes and packages 📦 the molecules ready for release
- Packaged molecules 📦are “pinched off” in vesicles from Golgi apparatus and move towards the plasma membrane
- Vesicle fuses with the plasma membrane
- Protein released out of the cell by exocytosis
17
Q
Light microscopes can be used to observe dead specimens? True or false
A
False
18
Q
Light microscopes can be used to observe tissue in colour? True or false
A
True
19
Q
Light microscopes can be used to observe organelles of cells? True or false
A
True
20
Q
Light microscopes can be used to observe the movement of cells? True or false
A
True
21
Q
What features of a 🌱 cell would you expect to be able to see under a light microscope?
A
The cell wall, the nucleus, the cytoplasm and the chloroplasts
22
Q
Explain why you can only see limited organelle when looking at a 🌱cell under a light microscope
A
The resolution of a light microscope is 200nm and the max magnification is 1500 times. The magnification and resolution are too low to observe most organelle of the cell.
23
Q
Scanning electron microscopes can be used to observe 2D images, true or false?
A
False
24
Q
Scanning electron microscopes can be used to observe cell surfaces, true or false?
A
True
25
Scanning electron microscopes can be used to observe cells in colour, true or false?
False
26
Scanning electron microscopes can be used to observe cells in real time, true or false?
False
27
Strengths and weaknesses of light and electron microscopes
Light microscopes strengths:
Cheap, portable, easy to use, can study living or dead specimens with them
Light microscopes weaknesses:
Limited resolution and magnification, most organelles are too small to see at this power
Electron microscopes strengths:
High magnification and resolution
Electron microscopes weaknesses:
Large, needs skills and training to operate, specimen must be dead
28
Which of these statements are true?
1) Stains can be used to distinguish between different cell types
2) Stains can be used to fix specimens
3) Stains can be used to distinguish different tissue types
4) Stains can be used to highlight particular organelle
1, 3 and 4 only
29
How would you prepare a temporary mount of a specimen for a light microscope?
Section the specimen, put it on a slide, stain it, put a coverslip over the specimen
30
How would you calculate magnification?
Image size divided by actual size
31
How would you calculate the image size?
Actual size times by magnification
32
How would you calculate the actual size of a cell?
Image size divided by magnification
33
Organelle present in animal cells
```
Nucleolus
Nucleus
RER
SER
Ribosomes
Mitochondria
Golgi apparatus
Centrioles
Plasma membrane
Cytoskeleton
```
34
Organelles present in plant cells🌱
```
Nucleus
Nucleolus
RER
SER
Ribosomes
Mitochondria
Chloroplasts
Golgi apparatus
Cellulose cell wall
Plasma membrane
Large central vacuole
Cytoskeleton
```
35
Prokaryotic cells don't have a nucleus, true or false?
True
36
Prokaryotic cells have many organelles, true or false?
False
37
Prokaryotic cells have a cellulose cell wall, true or false?
False
38
Prokaryotic cells have ribosomes, true or false?
True
39
Describe the differences in function between the RER, SER and Golgi apparatus
RER is coated with ribosomes that synthesise proteins
SER synthesises lipids
Golgi apparatus helps 📦 and modify proteins for exocytosis
40
Proteins cross the plasma membrane by what process?
Exocytosis
41
Why do the beta cells in the pancreas (beta cells produce insulin, a protein) have lots of RER?
RER coated with lots of ribosomes
Ribosomes synthesise proteins
Beta cells of the pancreas produce insulin, a protein
42
Suggest why beta cells in the pancreas need large amounts of ATP
Proteins are secreted from the beta cells by exocytosis which requires ATP/is an active process
43
Which are true?
1) The cytoskeleton is made of microtubules
2) The cytoskeleton is involved with the production of protein
3) Flagella and cilia are made of microfilaments
4) Microtubule proteins transport vesicles along microtubules
ONLY 1 and 4
44
Role of flagella
Movement of the cell
45
Role of cilia
Movement of the cell
| Movement of substances e.g. Mucus
46
Role of microtubules
To maintain the shape of the cell
47
Role of microtubule motors
Movement of vesicles along microtubules
48
How is the cytoskeleton involved in movement inside and outside of the cell?
Microtubule motors move vesicles along microtubules inside the cell
Flagella/cilia are made from microtubules on the surface of the cell which helps the cell to move
The lengthening and shortening of microtubules inside the cell helps the cell to move
49
Cytoskeleton
Network of protein fibres within the cell that give the cell structure and shape
50
🌟Microtubules
Hollow cylinders of tubulin
25nm diameter
Maintain cell shape
Anchors organelles
In flagella and cilia, the structure is a cylinder of 9 microtubules in a circle and 2 more microtubules in a central bundle
Can help move microbes
How chromosomes are moved during mitosis (spindle fibres)
How vesicles move from the ER to Golgi using microtubule motors (requires ATP)
51
Flagella and cilia
Sticks out of the surface of the cell
Each one is a cylinder with 9 microtubules in a circle and 2 more in a central bundle
Can move using ATP
52
Cilia
Large no. of them on ciliated epithelial cells
Moves egg down Fallopian tube
Beat to move mucus
53
🌟Intermediate filaments
```
10nm
Thick cables of keratin
Maintains cell shape
Anchors nucleus
Anchors organelles
```
54
🌟Actin microfilaments
```
2 intertwined strands of actin
7nm diameter
Maintains cell shape
Causes muscle contractions
Involved in cytokinesis
Allows pseudopodia seen by amoeba and some WBCs
```
55
Vesicles
Membrane bound sacs
| Carry substances
56
Features of prokaryotic cells
Mesosomes - inner folding, large SA for respiration
Ribosomes - synthesise proteins (smaller than in eukaryotes)
Plasmid - genetic material
Pilli - for conjugation
Slime capsule - keeps cell moist
Chromosomal DNA - contains instructions to make proteins
Cell wall - made of murein/peptidoglycan
57
Nucleus
```
Surrounded by nuclear envelope
Nuclear pores allow mRNA and nucleotides through
Contains genetic material (chromatin)
Contains nucleolus
Controls cell
```
58
Mitochondria
2 membranes separated by inter-membrane space
Inner membrane folded = cristae
Aerobic respiration takes place in mitochondria to release ATP
59
RER
System of cisternae
Ribosomes line it
Involved w/ protein synthesis and transport
60
SER
System of cisternae
Lacks ribosomes
Involved w/ synthesis and transport of lipids
61
Ribosomes
```
Involved w/ protein synthesis
Move along mRNA
Read nucleotide code to synthesise proteins
Ribosomes are made of rRNA + protein
1 large + 1 small subunit
```
62
Golgi apparatus
More compact that SER
Made of flattened membrane sacs
Modifies and packages 📦 proteins
Forms lysosomes
63
Lysosomes
Membrane sac
Contains digestive enzymes
Destroys worn out parts of cell
64
Cytoplasm
Aqueous
| Contains simple ions, amino acids, ATP, sugars, fat droplets
65
Cell membrane
```
Boundary between cell + environment
Fluid mosaic model
Phospholipid bilayer
Proteins
Cholesterol
Glycolipids
Glycoproteins
```
66
Centrioles
ONLY in animal cells
| Migrate to poles of cell during mitosis and produce microtubules (spindles) to pull chromosomes apart
67
Chloroplasts
```
PLANTS ONLY
Stroma
Thylakoids
Grana
Intergranal lamellae
Chlorophyll
Site of photosynthesis
```
68
Starch granules
PLANTS ONLY
| temporary stores of carbohydrates
69
Cell wall
Made of cellulose
Provides strength
Allows water to move through the plant
70
Plasmodesmata
PLANTS ONLY
gaps that allow neighbouring cells to link
Continuation of cytoplasm
71
Average diameter of prokaryotic cell
0.5-5 micrometers
72
Average length eukaryotic cells
20-40 micrometers
73
Ribosome diameter in prokaryotes
18nm
74
Ribosome diameter in eukaryotes
22nm
75
A structure associated with the cytoskeleton that can help cells move
```
Flagellum
Cilia
Microtubules
Microfilament
Undulipodium
```
76
2 processes inside the cell that rely on cytoskeleton for movement
Chromosomes moving
Cytokinesis
Movement of organelles
RNA in protein synthesis
77
What events happen following production of extracellular proteins until they are released?
```
Protein pinched off by Vesicle
Moves to Golgi apparatus
Golgi processes and packages
Moves in Vesicle to plasma membrane
Exocytosis
```
78
What structure secretes mucus?
Golgi Vesicle
79
Why do ciliated cells have lots of mitochondria?
They need a lot of energy to waft mucus
| V active
80
Vacuoles
Large, permanent organelle in plants
| Tonoplast filled w/water and sugars to keep the cell turgid
81
🌟Stages of exocytosis
Vesicle moves towards cell surface membrane along microtubules
Vesicle fuses with the cell surface membrane
Protein released out of the cell by exocytosis
Movement of vesicles on microtubules and fusion of vesicles with the membrane requires ATP
82
🌟Stages of endocytosis
Molecule binds w receptor
Cell surface membrane invaginates (requires ATP)
Membrane fuses w itself to form a vesicle
Vesicle moves through cytoplasm to destination organelle
83
🌟Roles of the cytoskeleton
Cell support + stability to maintain cell shape
Movement of cilia
Movement of flagellum to move cell
Changing cell shape e.g. endocytosis and exocytosis
Moving organelles around inside a cell
Anchoring organelles
Moving chromosomes and mRNA
