2 - Cells and Microscopy Flashcards
1
Q
Nucleus structure
A
Surrounded by a double membrane nuclear envelope with nuclear pores. Has chromosomes, (protein-bound, linear DNA) and one or more nucleolus
2
Q
Nucleus function
A
Nucleolus - site of rRNA product and makes ribosomes. DNA replication and transcription
3
Q
Cell membrane structre
A
Phospholipid bilayer
4
Q
Cell membrane function
A
Transport, cell recognition, fluidity, receptor
5
Q
SER structure
A
No ribosomes. Sheet like membranes linked to nucleus, form cisternae
6
Q
SER function
A
Create, store and modify carbohydrates
7
Q
RER structure
A
Has ribosomes. Sheet like membranes linked to nucleus, form cisternae
8
Q
RER function
A
Site of protein and glycoprotein synthesis.
9
Q
Cell wall structure (eukaryotic)
A
Cellulose. Has middle lamella (boundary between two adjacent cells)
10
Q
Cell wall function
A
Structural support and prevent bursting when undergoing osmosis
11
Q
Lysosome function
A
Contain digestive enzymes which break down material
12
Q
Ribosome structure
A
Small granules made of protiens and RNA. 80s and 70s
13
Q
Ribosome function
A
Site of translation in protein synthesis
14
Q
Vacuole structure
A
Single membrane sac filled with salts, sugars and AA. Has a tonoplast
15
Q
Vacuole function
A
Structural support. Store AA and sugars. Pigmented = attract pollinators
16
Q
Golgi apparatus structure
A
Stack of cristae
17
Q
Golgi apparatus function
A
Modify proteins received from the ER. Add carbohydrates to form glycoproteins. Then transported in vesicles .
18
Q
Lysosome structure
A
Formed when GA contains hydrolytic enzymes
19
Q
What are cristae?
A
Stacks of membranes creating flattened sacs in GA
20
Q
What are cisternae?
A
Network of tubules and flattened sacs. SER and RER
21
Q
What is a tonoplast?
A
Membrane around a vacuole
22
Q
What is a tonoplast?
A
Membrane around a vacuole
23
Q
Describe the capsule?
A
Slime layer outside cell. Stops it from drying out and sticking together
24
Q
Describe the cell wall (prokaryotic)
A
Murein
25
Describe the cell membrane (prokaryotic)
Same to eukaryotic - boundary between inside and outside
26
Describe the flagellum
Tail that rotates to move
27
Describe the nucleoid
Single circle of DNA that has genetic materia;
28
Describe the plasmid
Small loops of DNA that contributes to antibiotic resistance
29
Describe the mesosome
Inner folding of cell membrane. Large SA for enzymes used in respiration
30
Describe the ribosomes (prokaryotic)
70s. Not attached to membrane
31
Describe the ribosomes (prokaryotic)
70s. Not attached to membrane
32
What is homogenisation?
Break cell wall in blender and filter to remove debris
33
What is ultracentifugion?
Fractions of filtered homogenate are filtered in tube
34
3 things the solution needs to be
Buffered, ice cold, isotonic
35
Why does solution need to be buffered?
pH is constant so enzymes don't denature
36
Why does solution need to be ice cold?
Enzymes are slow so don't destroy organelles
37
Why does solution need to be isotonic?
Prevents osmosis so organelle can't burst/shrink
38
Process of cell fractionation
1. Chop up in ice-cold, isotonic and buffered solution
2. Filter to remove debris
3. Use centrifuging so most dense forms pellet and suspending organelles form supernatant
4. Pour into another tube and repeat
39
Describe the phospholipid bilayer
Hydrophobic fatty acid and hydrophilic phosphate group. :) lipid soluble to enter and prevents water soluble substances to enter or leave
40
Describe the glycolipid
Maintain stability, cell recognition and attachment
41
Describe the glycoprotein
Attach to form tissues, cell recognition
42
Describe the intrinsic protein
Carrier and channel proteins
| Ions, AA, sugars pass
43
Describe the extrinsic protein
Hormone receptor, cell recognition
44
Describe cholestrol
Control fluidity and prevents water soluble and dissolved ions from leaving
45
Describe the carbohydrate branch
Nothing
46
Describe the carbohydrate branch
Nothing
47
Define diffusion
Net movement of molecules from a high to low concentration down the concentration gradient until evenly distributed
48
What impacts rate of diffusion?
Size, concentration, distance, temperature, SA
49
How does size impact rate of diffusion?
Less KE needed at same temp so move quicker
50
How does concentration impact rate of diffusion?
Bigger conc. gradient = more likely to collide over region
51
How does distance impact rate of diffusion?
Small = time taken to travel is short
52
How does temperature impact rate of diffusion?
More KE = move quicker = more likely to collide
53
How does SA impact rate of diffusion?
More space for diffusion = happen faster = more opportunities for collisions
54
Define facilitated diffusion
Movement of molecules from a high to low concentration with the use of proteins
55
What molecules can be transported by diffusion?
Lipid soluble, non-polar, small, O2, C02
56
What proteins are involved in facilitated diffusion? How?
Carrier - large molecules attach and change shape to pass
Channel - form pores and charges particles
Both hydrophilic
57
What molecules can be transported by facilitated diffusion?
AA and glucose, water soluble, charged ions
58
What molecules can be transported by facilitated diffusion?
AA and glucose, water soluble, charged ions
59
What impacts permeability? (5)
Size, lipid soluble, alcohol conc., electrical charge, SA
60
What is the unit for pressure?
KSI
61
Water potential of pure water
0
62
Define osmosis
Movement of water molecules from a highwater potential to an area of low water potential through a selectively permeable membrane.
63
Define active transport
Movement of molecules from a high to low concentration by moving against the con. gradient. Involves ATP and carrier proteins
64
Osmosis pratical
Potato chip
65
Process of active transport
1. Molecule binds to carrier protein at receptor site
2. ATP binds to protein at other side which splits (hydrolysis so ADP + phosphate)
3. protein changes shape and opens at other side
4. molecule released
5. ATP reformed and protein reverts to original shape
66
What impacts rate of active transport? (4)
Number of carrier proteins, carrier protein speed, rate of respiration
67
Small protein adaptations (4)
Big SA, villi, thin epithelial layer, good blood supply
68
Ions involved in co-transport
Na+ and K+
69
Process of co-transport
1. C6H12O6and Na+ into epithelial cells (co-trans)
2. Na+ into blood from epithelial cells and K+ into epithelial cells from blood (act.tra)
3. C6H12O6 from epithelial cells to blood (f.diffusion)
70
T-cell response name
Cell mediated
71
B-cell response name
Humoral
72
Two types of defence and examples
Specific - T and B cells
| Non-specific - phagocytosis, physical barrier
73
3 ways how lymphocytes recognise body cells
Foetus (collide w other cells)
Lymph. collide with own material
Survive if receptors for with foreign antigen
74
What is a macrophage?
APC that is a WBC
75
What are the 2 types of phagocyte
Neutrophil and monocyte
76
What is a neutrophil?
Phagocyte - short life span, arrive first and die after engulfing
77
What is a monocyte?
Phagocyte - mature to macrophage before engulfing
78
Describe process of phagocytosis
1. Pathogen in blood stream and phagocyte recognises foreign antigens
2. Receptors bind and engulf
3. Pathogen enclosed in a phagosome
4. Phagosome and lysosome fuse
5. Empty contents into phagosome (hydrolytic enzymes)
6. Pathogen destroyed and exocytosis happens
79
4 ways how phagocytes are specialised and description
Cytoskeleton - change shape to engulf pathogen and move lysosomes
Mitochondria - cell movement and phagocytosis need energy
Ribosomes - Protein synthesis (lysosome enzymes)
Lobed nucleus - enter narrow gaps and change shape
80
Types of T-cells and description
Cytotoxic - destroy antigen
Helper 1 - stimulate phagocytosis
Helper 2 - stimulate B-cell production
Memory - remember antigen
81
How T cells work
Phagocytosis - WBC presents antigen - fuse with T cells - mitosis
82
What do B cells undergo?
Clonal expansion
83
Process of B cell production
Phagocyte becomes APC - present antigen to B cell - antigen is complementary to receptor - B cell presents antigen - bind and activate - T-helper cells bind and secrete cytotoxins which stimulates mitosis
84
Types of B cells and description
Plasma - secrete antibodies and primary immune response
| Memory - if encounter same antigen, divide rapidly to make plasma cells. Secondary response
85
Label an antibody
```
Light chain - not attached bit
Heavy chain - connected bit
Variable region - top half
Constant region - bottom half
Antigen binding site - top
Receptor binding site - bottom
```
86
Bond in an antigen
Disulphide bond
87
Antigen bonding to binding site forms a ….
Antigen - antibody complex
88
4 functions of antibodies
Agglutination, opsonisation, antitoxins, lysis
89
Describe agglutinstion
Pathogens are clumeped together
90
Describe oposonisation
Pathogens are coated with antibodies
91
Describe antitoxins
Toxins produced by pathogen are neutralised
92
Describe lysis
Bacteria are destroyed by digestion and rupture bacteria membrane
93
Name the 3 types of immunity
Herd, active, passive
94
Describe herd immunity
Protection by a viral percentage of population by being vaccinated
95
Describe active immunity
Ability to produce own antibodies
96
Describe passive immunity
Just receive the antibodies
97
Two methods to get active immunity
Natural - after infection
| Artificial - Vaccination
98
Two methods to get passive immunity
Injection following infection and antibody from mother to foetus
99
4 ways a vaccination program is successful
Economical
Few side effects
Stable and easy to store
Easy to administer
100
3 ways a vaccination program is unsuccessful
Pathogen frequently mutates
Pathogen hides from immune system
People refuse to be vaccinated
101
Process of being immune by vaccination
1. Pathogen enters body and T/plasma cells made
2. B and T cells differentiate
* first exposure and primary response 10-17 days*
3. Become ill due to slow process
* Secondary response*
4. Second exposure to same antigen (2-7 days and higher magnitude/prolonged)
5. Happens due immunological memory
102
Difference between HIV and AIDS
```
HIV = pathogen
AIDS = Disease
```
103
How is HIV transmitted?
unprotected sex, birth, sharing needles
104
How does HIV impact the body?
Destroy T cells so weak immune response (supressed)
105
Define opportunistic infections
Not likely to impact healthy people but causes harm if immune system is supressed
106
Signs and symptoms of AIDS
1. Acute infection - divide rapidly and seed in body (no
symptoms and inactive)
2. 2-4 weeks later, flu like symptoms and swollen lymph glands
107
What is the ELISA test?
Detect small quantities of proteins (antigens)
108
Name 6 things found in HIV
Lipid envelope, matrix, RNA strands, glycoprotein, capsid, reverse transcriptase
109
What is a lipid envelope? (HIV)
Lipid bilayer that surrounds virus. Allows to fuse with other membranes
110
What is a matrix? (HIV)
Protein layer
| Structural support
111
What is a glycoprotein? (HIV)
Bind with CD4 on T helper cells - surface protein
112
What is a capsid? (HIV)
Protein coat - genetic material and some enzymes
113
What are RNA strands? (HIV)
2 - contain al genetic material
114
What is reverse transcriptase? (HIV)
Enzymes that catalyse synthesis of rna -> dna
115
3 uses of monoclonal antibodies
Pregnancy test, cancer, medical diagnosis
116
How are monoclonal antibodies used in pregnancy tests?
HCG produced by placenta binds to MCA and move along strip
117
How are monoclonal antibodies used in cancer treatment?
Block chemical signals for growth
118
How are monoclonal antibodies used in medical diagnosis's?
Obtain sample of blood and detect quantity of a substance
119
3 reasons why monoclonal antibodies arent ethical
Involve mice
Caused some deaths
Testing has dangers
120
Name 3 types of microscope
SEM, TEM OLM (optical light)
121
3 pros of SEM
3D
See internal structures
Still fairly high resolution
122
3 cons of SEM
Vacuum needed
Staining process
Lower resolution
123
3 pros of TEM
Highest resolution - short wave length
| Chemical analysis
124
3 cons of TEM
2D
Sample destroyed by e-
Need staining process
125
3 pros of light microscope
Cheap
Colour
Portable
126
1 con of light microscope
Low resolution - long wavelength
127
Why does the nucleus form at the bottom of the test tube in centrifuging?
It's the most dense
128
When a vaccine is given to a person, it leads to the production of antibodies against a disease-causing organism. Describe how.
1. Vaccine contains antigen from pathogen
2. Macrophage presents antigen on its surface
3. T cell with complementary receptor protein binds to antigen
4. T cell stimulates B cell
5. With complementary antibody on its surface
6. B cell secretes large amounts of antibody
7. B cell divides to form clone all producing same antibody
