Module 2 - Cells Flashcards
1
Q
What is the structure of cilia (and undulipodia)
A
- 9 pairs of microtubules arranged in a cylinder with a pair in the middle
- 9 + 2 arrangement
- Each pair has its own tiny motor protein
2
Q
What is the function of cilia (and undulipodia)
A
- Wafts mucus
- propelling sperm
3
Q
What is the structure of centrioles?
A
- 9 Triplets of microtubules arranged in a cylinder
- a pair is a centrosome
4
Q
What is the function of centrioles?
A
produces spindle fibres during cell division
5
Q
What is the structure of Flagellae?
A
a single actin fibre
6
Q
What is the function of Flagellae?
A
moves in a whip like function to propel bacteria
7
Q
Where are the intermediate fibres located?
A
Randomly scattered around the cell
8
Q
What is the structure of intermediate fibres?
A
Long strands of protein made from actin
9
Q
What is the function of intermediate fibres?
A
- They give mechanical strength to the cells
- maintain integrity
10
Q
Where are the microfilaments located?
A
forming a network around the inside of the cell
11
Q
What is the structure of microfilaments?
A
contractile fibres formed from the protein actin
12
Q
What is the function of microfilaments?
A
- Cell movement
- Cell contraction
- Cell division
13
Q
Where are the microtubules located?
A
concentrated around the outside of the cell
14
Q
What is the structure of microtubules?
A
Hollow tubes made of alpha and beta tubulin
15
Q
What is the function of microtubules?
A
- provides shape of cell
- cell movement
- cell division
16
Q
What is the structure of flagellum?
A
a single protein filament rotated by a molecular motor
17
Q
What is the function of flagellum?
A
Used for cell movement
18
Q
What is the structure of the cell surface membrane?
A
Phospholipid bilayer studded with proteins
19
Q
What is the function of the cell surface membrane?
A
Controls what enters and leaves the cell
20
Q
What is the structure of ribosomes?
A
smaller than those in eukaryotes
21
Q
What is the function of ribosomes?
A
protein synthesis
22
Q
What is the structure of the cell wall?
A
made of peptidoglycan
23
Q
What is the function of the cell wall?
A
to help the cell to resisit the effects of high tugor pressure
24
Q
What is the structure of the cytoplasm?
A
liquid mostly composed of water
25
What is the function of the cytoplasm?
medium for chemical reactions within the cell
26
What is the structure of pili?
short, projections of the cytoskeleton within the plasma membrane
27
What is the function of pili?
To help bacteria move in response to stimuli
28
What is the structure of plasmids?
Small, circular, double -stranded DNA molecule
29
What is the function of plasmids?
Can be exchanged between bacteria by conjugation
30
What is the structure of free chromosomal DNA?
one molecule DNA, chromosome is supercoiled to make it compact
31
What is the sfunction of free chromosomal DNA?
Helps to store and transmit biological information to another cell
32
What is the structure of centrioles?
Small, hallow cylinders made of microtubules
33
What is the function of centrioles?
produces spindle fibres in cell division
34
What is the structure of vesicles?
small fluid filled sacs surrounded by a membrane
35
What is the function of vesicles?
Used to transport cells around the body
36
What is the structure of the cell surface membrane?
thin layer of fats and proteins found around the outside of the cell
37
What is the function of the cell surface membrane?
Controls the movement of molecules in and out of the cell
38
What is the structure of rough endoplasmic recticulum?
a system of interconnected membrane sacs called cristernae studded with ribosomes.
39
What is the function of rough endoplasmic recticulum?
proteins for export from the cell are made here
40
What is the structure of ribosomes?
a small organelle made of protein and RNA
41
What is the function of ribosomes?
proteins are made here
42
what is the structure of the nucleolus?
spherical region within the nucleus
43
what is the function of the nucleolus?
produces ribosomes
44
what is the structure of the smooth endoplasmic reticulum?
a system of interconnected membrane bound sacs called cisternae
45
what is the function of the smooth endoplasmic reticulum?
Synthesises and processed lipids
46
What is the structure of mitochondria?
double membrane bound organelle containing cristae
47
What is the function of mitochondria?
site of aerobic respiration
48
what is the structure of the nucleus?
large organelle surrounded by a double membrane with pores.
49
what is the function of the nucleus?
contains DNA in the form of chromatin
50
what is the structure of the golgi appraratus?
a group of dish shaped fluid filled sacs called cristernae
51
what is the function of the golgi appraratus?
processes and packages proteins for export
52
what is the structure of the lysosome?
a specialised vesicle containg digestive enzymes
53
what is the function of the lysosome?
the enzyme used to break down the waste products
54
what is the structure of the cell wall?
a rigid but porous network of cellulose fibres
55
What is the function of the cell wall?
giving structural supoort to plant cells by helping maintaining tugor pressure
56
What is the structure of the chloroplasts?
double membrane bound oval organelles conatining thylakoids
57
what is the function of chloroplasts?
site of photosynthesis
58
what is the structure of the permanent vacuole?
a sac containing cell sap surrounded by a membrane called the tonoplasts
59
what is the function of the permanent vacuole?
Involved in maintaining tugor pressure
60
Stage micrometer and gracticule
1 gracticule division = a number of micrometers/ number of gracticle divisions.
graticle divisions x magnification factor = measurement (um)
61
produces and secretes proteins (1)
mRNA is made in the nucleus and leaves via the nucleus pore
62
produces and secretes proteins (2)
instructions for making the mRNA are contained in the mRNA
63
produces and secretes proteins (3)
mRNA attached to the Ribosomes
64
produces and secretes proteins (4)
The protein is synthesised on the ribosome and passed the RER, where it is packaged into vesicles which are moved by the cytoskeleton to the gogi apparatus
65
produces and secretes proteins (5)
The protein is modified at the gogi apparatus then put into vesicles and moved towards the cell surface membrane for exocytosis
66
what is calibration?
It means to work out each division on the gracticule measures (on the stage micrometer) at a particular magnification
67
what is magnification?
- The number of times greater the size of the image is that the size of the real object.
- Magnification = Image size/size of object
68
What is Resolution?
- The ability to distinguish between objects that are very close together - higher resolution means more detail
-They cannot be seen using optical microscopes because its resolution is too low
69
Why is staining used?
- To make cells more visible
- To increase contrast
- Identify different cell components
70
Stains are used for specific biochemicals
- iodine solution stains starch granules blue and black; methylene blue stains genetic material in animal cells blue
- In confocal microscopy, fluorescent dyes can be used to tag specific molecules
71
Scannning Electron Microscope
A beam of electrons is sent across the surface of a specimen and the reflected electrons are collected
72
Features of a Scannning Electron Microscope
- specimen is non-living
- x500 000 magnification
- 3-10nm Resolution
-3D images
- - Black and white images
73
Transmission electron microscope
a beam of electrons is transmitted through a specimen and focused to produce an image
74
Features of a Transmission electron microscope
- non-living specimen
- x500 000 magnification
- 0.5nm resolution
- 2D images
- black and white images
75
laser scanning confocal microscope
emitted light from the specimen fitted through a pinhole
76
What are the features of a laser scanning confocal microscope
- only light radiated from very close to the local plane is detected
- living and non-living specimen
- x400 magnification
- 120nm resolution
- 2D and 3D images produced at different focal points
77
Light Microscope
light shines down through the objective onto the specimen
78
Features of a light microscope
- light reflected/scatter to the objective is then imaged back at the eyes
- specimen is living or dead
- x2000 magnification
- 200nm Resolution
- stains are used
79
What is the structure of the cytoskeleton?
Is a stability of fibres necessary for the shape and stability of the cell
80
What is the function of the cytoskeleton?
- Supports the cell
- Give the cell its shape
- Controls cell movement
- Holds organelle in place
81
Measurements
cm - mm = x10
mm - um = x1000
um - nm = x1000
cm - m = /100
m - mm = 1000
82
How do you calculate magnification?
image size = actual size x magnification
