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B2-Cells Flashcards

1
Q

Structure [2] and function [1] of cell surface/plasma membrane ? [3]

A

-Mainly lipids and proteins
-Receptors on surface for recognition

-Regulates movement of substances in + out

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2
Q

Structure [3] and function [2] of Mitochondria ? [5]

A

-Double membrane
-Inner membrane folds + forms crista
-matrix contains enzymes involved in respiration

-Site of aerobic respiration
-Energy released/ATP produced

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3
Q

Structure and function of Nucleus ? [3]

A

-Bound by a ‘nuclear envelope’
-Contains chromosomes (protein bound linear DNA)
-Contains nucleolus which produces RNA to make ribosomes

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4
Q

Structure and function of golgi apparatus ? [2]

A

-Modify, processes and packages proteins and lipids
-Golgi vesicles store lipids and proteins and transports out of cell

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5
Q

Structure and function of lysosomes ? [3]

A

-A type of vesicle formed from golgi
-Contains and transports digestive enzymes called Lysozymes
-Surrounded by a membrane

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6
Q

Structure [3] and function [1] of ribosomes? [4]

A

-Found freely in the cytoplasm or part of RER
-Made up of proteins and lipids
-80S in eukaryotic

-Site of translation for photosynthesis

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7
Q

Structure and function of Rough Endoplasmic Reticulum? [2]

A

-Ribosomes on membrane, some free floating
-Processes proteins

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8
Q

Structure and function of Smooth Endoplasmic Reticulum? [2]

A

-No ribosomes
-Lipids are synthesised and processed here

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9
Q

Structure [4] and function [1] of chloroplast? [5]

A

-Small, flattened strcutre
-Double membrane
-Inside stacked membrane called thylakoids (grana in stacks)
-Stroma=fluid containing enzymes

-Site of photosynthesis

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10
Q

Structure and function of cell wall? [4]

A

-Rigid structure which supports and structures cells
-Plants and algae= Cellulose cell wall
-Fungi= Chitin cell wall
-Prevents changing of shape

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11
Q

Structure [2] and function [2] of vacuole? [4]

A

-Membrane bound organelle
-Contains cell sap

-Involved in isolation of unwanted chemicals
-Maintains pressure and turgidity

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12
Q

Prokaryote structure [5]

A

-Much smaller than eukaryote
-No membrane-bound organelles
-Smaller ribosomes (70S)
-No nucleus, circular DNA
-Cell wall made from Murein

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13
Q

Virus structure [3]

A

-Protein coat (capsid)
-Genetic material = DNA or RNA
-Attachment proteins= help virus attach and enter host cell

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14
Q

Light microscope principles?

A

Uses long light wavelengths
-Light passes through specimen
-Into magnifying lenses of microscope
-Into objective viewing lens
-Into eye, brain forms image

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15
Q

TEM principles?

A

Uses electromagnets to focus electron beam

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16
Q

SEM principles?

A

Beam of electrons move back and forth across cell’s surface, creating details of cell surface characteristics

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17
Q

Light microscope advantages? [5]

A

-Specimen can be alive
-Cheap
-Simple/easy to use + maintain
-Small therefore easily transported
-Coloured images

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18
Q

Light microscope disadvantages? [3]

A

-Lower magnification and resolution
-object smaller than wavelength of light cannot be seen
-Cannot be used to study ribosomes, lysosomes, etc

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19
Q

TEM advantages? [2]

A

-High resolution so organelles can be separated
-Detailed images

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20
Q

TEM disadvantages? [5]

A

-Must be performed in a vacuum
-Specimen must be thin
-Specimen must be dead
-No colour
-May contain artefacts

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21
Q

SEM advantages? [3]

A

-3D images
-Specimens can be of any thickness
-Shows surface of specimen

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22
Q

SEM disadvantages? [3]

A

-Lower resolution
-No colour
-May contain artefacts

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23
Q

What are the three main steps to cell fractionation?

A

-Homogenisation
-Filtration
-Ultracentrifugation

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24
Q

1- What three things must the solution be during cell fractionation?

A

-Cold
-Isotonic (same water potential)
-Buffer (same ph)

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25
Why should the solution be cold during cell fractionation?
Reduces enzyme activity and prevents enzymes from denaturing
26
Why should the solution be isotonic during cell fractionation?
Prevents enzyme activity and prevents enzymes from denaturing
27
Why should the solution be a buffer solution during cell fractionation?
Prevents osmosis from occuring
28
2- Homogenistation- what is it and why is it done?
-Blending the solution -Breaking apart the cell wall/membrane -Releases the organelles
29
3- Filtration- why is it done?
- Removes large cellular debris
30
4- Ultracentrifugation- how is it done & keywords
-Centrifuge at a low speed- collect pellet containing dense, heavier organelles -Leftover solution that isnt the pellet is the SUPERNATANT -Centrifuge the supernantant again, increasing the speed -Repeat
31
What order do the organelles pellets form?
-Nucleus -Chloroplasts -Mitochondria -Lysosomes/golgi -ER Ribosomes
32
What is cancer?
Unrestrained cell growth and division, leading to the formation of a cluster of cells (called a tumour).
33
What is a benign tumour?
A tumour which is encapsulated and noninvasive
34
What is a malignant tumour?
A tumour which is not encapsulated and invasive, which can undergo metastasis (can spread throughout the body)
35
What is chemotherapy?
A type of therapy which interferes with the cell cycle and halts division.
36
First stage of binary fission:
The cells elongate and the DNA is replicated.
37
Second stage of binary fission:
The cell wall and plasma membrane begin to divide.
38
Third stage of binary fission:
A cross-wall forms around the divided DNA.
39
Fourth stage of binary fission:
The cells separate.
40
Mitotic Index calculation:
Number of cells undergoing mitosis/Total number of cells
41
What happens during G1 phase of Interphase in the cell cycle? [2 points]
-The cell is metabolically active and grows. -The duplication of organelles occurs.
42
What happens during S phase of Interphase in the cell cycle?
The DNA replicates
43
What happens during G2 phase of Interphase in the cell cycle? [2 points]
- New organelles are created - The cell continues to grow
44
What happens during cytokinesis?
The separation of the membrane.
45
What happens during prophase? [2]
-The chromosomes become visible under a microscope -Nuclear envelope breaks down
46
What happens during metaphase? [2]
-The chromatids line up at the equator of the cell -The spindle fibres attach to the chromatids by their centromeres
47
What happens during anaphase? [3]
-The centromeres divide to split each pair of chromatids -The spindle fibres contract and shorten, pulling the chromatids to opposite poles of the cell -The chromatids appear V-shaped
48
What happens during telophase? [1]
-Nuclear envelope forms two new nuclei
49
Where does the phospholipid head face?
Face aqueous
50
What is a glycolipid and what is its function?
Carbohydrate chain attatched to a lipid. -Cell protection/recognition -Cell adhesions -Uptake and entry of selected substances
51
What is the extrinsic proteins?
Sits on the periphery of the membrane
52
What is cholesterol for?
Helps to maintain the fluidity of the membrane, preventing it from becoming too rigid when temperatures drops and too fluid when temperatures are high
53
What is the intrinsic protein?
Spans the membrane 2 types: - Channel proteins= allow passive movement of substances that are too big or charged to fit through the bilayer - Carrier proteins= allow passive movement of some substances
54
What is a glycoprotein?
Carbohydrate chain attached to a protein Same functions as gylcolipid
55
Similarities between the structures of chloroplasts and mitochondria? [3]
-Both are double-membraned -Both contain circular DNA -Both contain ribosomes
56
Differences between the structures of chloroplasts and mitochondria? [2]
-Thylakoids & grana vs cristae -Stroma vs matrix
57
Why is the model for membrane known as the fluid mosaic model? [3]
- Fluid= the molecules move freely laterally - Mosaic= The proteins are disrupted throughout the membrane unevenly - Model= The agreed structure is based upon experimental + chemical evidence
58
What is the permeability of a plasma membrane?
Partially permeable
59
What are the 5 types of transport processes?
- Simple diffusion - Facilitated diffusion - Active Transport - osmosis - Co- transport
60
What is simple diffusion?
The net passive movement of molecules from an area of high concentration to an area of low concentration
61
6 factors which affect the rate of diffusion?
- Temperature - Concentration gradient - Stirring/movement - Surface area - Distance/thickness of diffusion distance - Size of molecule
62
What is facilitated diffusion?
Diffusion using: - Protein channels - Carrier molecule
63
What is required for active transport? [2]
- Metabolic energy in the form of ATP - Specific carrier proteins
64
How do carrier proteins work? [4]
- Molecules bind to carrier protein receptor site - ATP binds to protein (ADP+P) causing protein to change shape and open - Molecule released on the other side - Phosphate is released from protein and protein reverts to original shape
65
What is Endocytosis?
Bringing molecules into the cell
66
What is Exocytosis?
Moving molecules out of the cell
67
What is osmosis?
The passage of water from a region where it has a higher water potential to a region where it has a lower water potential through a selectively permeable membrane
68
What is an isotonic solution?
No net movement of water particles, as the two have the same water potential
69
What is the hypertonic solution?
Water particles move out of the cell. The cell membrane shrinks and detaches from the cell wall (plasmaolysis). The water potential is lower in the solution compared to the cells.
70
What is a hypotonic solution?
Water particles move into the cell. The cell swells and bursts. The water potential is higher in the solution compared to the cells.
71
What is a protoplast?
Consisting of the outer cell surface membrane, nucleus, cytoplasm, and the inner vacuole membrane
72
What is an aquaporin?
Special channel proteins allowing water to pass through the membrane
73
What is the Ileum?
one in three sections of the small intestine
74
What is co-transport?
The coupled movement of substances across a cell membrane via a carrier protein.
75
What is a non-specific cell mediated response? (+ examples)
Immediate and same for all pathogens (e.g physical and chemical barriers, phagocytosis)
76
What is a specific cell mediated response? (+ examples)
Slower and specific to each pathogen (e.g T and B lymphocytes)
77
What is a macrophage?
Another name for phagocytes
78
Two examples of white blood cells:
- Phagocytes - Lymphocytes
79
Two examples of lymphocyes
T cells B cells
80
Where to T cells mature?
In the thymus gland
81
Where do B cells mature?
In the bone marrow
82
What do T helper cells bind to?
Antigens presented on the antigen presenting cell
83
What four things can T cells do after having cloned?
- Produce memory cells - Produce killer T cells - Stimulates B cells to divide (creating antibodies) - Produce more phagocyes/macrophages to come to the area
84
What do cytotoxic/killer T cells do? (3 steps)
- Bind to infected cell - Releases perforin, which makes holes in infected cell's membrane - Enzyme enters and infected cell is destroyed
85
Three types of T cells:
- T helper cells - T killer cells (cytotoxic) - T memory cells
86
What do B cells produce?
Antibodies
87
What is an antigen?
A protein on the cell surface membrane which stimulates an immune response
88
Five examples of the first line of defence:
- Saliva (antibacterial enzymes) - Tears (antibacterial enzymes) - Skin (physical barrier) - Stomach acid (low pH) - Mucus lining
89
Four things that antigens enable the immune system to identify:
- Pathogens - Cells from other organisms of the cell species - Abnormal body cells - Toxins
90
Six (simple) stages of phagocytosis:
- Attraction - Recognition and attachment - Endocytosis - Bacteria within a phagocytic vacuole - Fusion of lysosomes and phagocytic vacuole - Killing and digestion
91
Four cells that have antigens:
- Cancer cells - Pathogens - Foreign cells - Toxins
92
Why do we get some diseases twice?
Antigenic variability means that the memory cells no longer recognise the antigen, therefore the body must initiate another primary response to that variation
93
What is active immunity?
Exposure to the antigen, long-term
94
What is passive immunity?
No exposure to the antigen, body provided with ready made antibodies, short-term
95
Natural active immunity
You get the disease- have memory
96
Artificial active immunity
Use of vaccines
97
Natural passive immunity
Given via breast milk, no memory, maternal antibodies
98
Artificial passive immunity
Injected, e.g antivenoms for snake bite, tetanus, rabies, etc
99
What is herd immunity?
Immunity that occurs when a large enough proportion of the population are immune so that a disease is unlikely to spread to those who are not.
100
Vaccination/Immunisation definition:
- Introduction to a dead or attenuated antigen into the body which stimulates active immunity against a disease.
101
Attenuated meaning
Chemical or genetic modification of a pathogen.
102
Ethical issues of vaccination
- Testing on animals - Side effects - Conspiracies and misinformation - Expensive
103
HIV structure
- Spherical shape - RNA core, enzyme reverse-transcriptase - outer capsid - Extra outer layer of membrane, comes from previous host cell [envelope] - Attachment protein, enables it to attach to host cell
104
Reverse transcriptase
opposite of transcription, so RNA to DNA, helps virus to replicate
105
Why does HIV lead to AIDS
Attacks T-cells therefore weakens the immune system
106
What is the latency phase in HIV and how long does this last?
Up to 10 years, replication at low levels
107
When is it diagnosed as AIDS?
once symptoms of failing immune system start to appear and numbers of T-cells drop critically low
108
What is AIDS short for?
Acquired Immune Deficiency Syndrome

Biology (4 decks)

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