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2 - Cells Flashcards

1
Q

The role of the disulphide bridge in forming the quaternary structure of an antibody

A

Joins 2 different polypeptides

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2
Q

How does HIV affect the production of antibodies when AIDS develops in a person?

A

No antibodies produced because HIV destroys TH cells, so no B cells are activated

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3
Q

Describe how B lymphocytes respond to vaccination

A

B cell binds to complementary antigen

B cell divides by mitosis

Plasma cells release antibodies

Plasma cells develop memory cells

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4
Q

Role of an organelle in digesting bacteria

A

Lysosomes fuse with vesicle and release hydrolytic enzyme

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5
Q

Structures found in all prokaryotic and eukaryotic cells

A

Cell membrane

Ribosomes

Cytoplasm

DNA

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6
Q

2 uses of amino acids in cell replication

A

Used in protein synthesis so more DNA polymerase

Used in respiration, so more ATP for DNA replication

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7
Q

Feature of chloroplast which allows proteins to be synthesised

A

DNA

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8
Q

Difference between chloroplast DNA and Nuclear DNA

A

Chloroplast DNA is not associated with histones, but nuclear DNA is

Chloroplast DNA is circular, nuclear is linear

Chloroplast DNA is shorter than nuclear

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9
Q

5 organelles involved in the production, transport and release of proteins

A

DNA is code for protein

rER produce protein

Mitochondria produce ATP fro protein synthesis

Golgi apparatus package/modify

Vesicles transport

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10
Q

Strength of TEM over SEM

A

Higher resolution

View internal structures

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11
Q

Organelle found in both a chloroplast and prokaryotic cell

A

Ribosome

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12
Q

Main biological molecules in cell membrane

A

Phospholipids

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13
Q

Main biological molecules in cell wall

A

Murein / glycoprotein

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14
Q

Which organelle is made of polysaccharides?

A

Cell wall

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15
Q

Replication of bacteria by binary fission

A

Replication of Circular DNA

Replication of plasmids

Division of DNA to produce daughter cells

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16
Q

Arrangement of chromosomes at prophase

A

Chromosomes become visible as they are condensing

Chromosomes arranged at random as there is no spindle activity

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17
Q

Fixed position occupied by a gene on a DNA molecule

A

Locus

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18
Q

Effect of stopping the formation of spindle fibres on cell division

A

Centromeres cannot attach to spindle

So no metaphase and chromatids cannot seperate on spindle

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19
Q

Permeability of the plasma membrane

A

Selectively permeable

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20
Q

Phospholipid

A

A molecule consisting of glycerol, 2 fatty acids, and a phosphate-linked head group

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21
Q

Role of cholesterol in the plasma membrane

A

sits with the phospholipids in the core of the membrane

Make the membrane more rigid, helping to maintain the shape of animal cells

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22
Q

3 factors effecting the permeability of membranes

A

Temperature

Solvent conc

pH

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23
Q

Effect of temperature on membrane permeability

A

Higher temps increase the fluidity of the membrane, increasing its permeability

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24
Q

Effect of solvent concentration on membrane permeability

A

The more easily the phospholipid bilayer is dissolved, the more permeable the membrane is

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25
Effect of pH on membrane permeability
pH affects the protein structure in the cell membrane
26
4 things immune cells can detect
Toxins Abnormal body cells Cells from other organisms Pathogen
27
4 Stages of the immune response
1. Phagocytosis 2. Activation of T cells 3. Activation of B cells 4. Production of antibodies
28
Phagocytosis
Detection of antigens Engulfing and digestion of pathogen Presenting antigen
29
How is the pathogen engulfed in phagocytosis?
Cytoplasm surrounds pathogen & Is sealed in a phagosome
30
How is the pathogen digested in phagocytosis?
Lysosomes which contain proteolytic enzymes
31
Importance of presenting antigens in phagocytosis
Antigens can activate other cells in the immune response
32
What cells do antigens activate?
T-helper cells
33
Role of TH cells
Activates other cells, including TC and B cells
34
Role of TC cells
Release toxins which bind to and kill other cells
35
What do B cells do upon activation?
Divide into identical plasma cells
36
Clonal selection
The process where B cells detect antigens and form antibody-antigen complexes
37
What does clonal selection lead to?
Clonal expansion
38
Clonal expansion
The production of many genetically identical daughter cells through cell division of the activated B or T lymphocyte
39
Agglutination
An antigen reacts with its corresponding antibody, resulting in visible clumps of bacterial cells
40
Uses of monoclonal antibodies
Targeted medication Medical Diagnosis
41
How are monoclonal antibodies used in medical Diagnosis?
Indicate presence of a specific antigen Antibodies are attached to a dye, fluorescent / radioactive marker When complementary antigen is present, binding will make dye visible
42
How are monoclonal antibodies used in targeted medication?
Cancer cells have abnormal antigens which monoclonal antibodies can abnormally bind to Specificity reduces damage to other cells
43
5 steps of the ELISA test
1, fixing of antigens to bottom of beaker 2. addition of blood 3. wash beaker 4. add secondary antibodies 5. add solution
44
What happens when blood is added in the 2nd step of the ELISA test?
antigen-antibody complexes formed
45
Why is the beaker washed in the ELISA test?
Unblinded antibodies removed
46
What happens when secondary antibodies are added in the ELISA test?
Colour changes if binds to other antigens
47
Purpose of adding solution in ELISA test
Colour change = infection
48
How is HIV replicated? - 6 steps
1. glycoproteins bind to TH cells 2. capsid injected into TH cells and its contents released 3. Reverse transcriptase turns RNA --> DNA and DNA moves into TH nucleus 4. Integrase inserts HIV DNA into TH DNA 5. Expression 6. Release of HIV
49
How is HIV treated?
Anti-viral drugs target reverse-transcriptase enzyme
50
Interphase
G1 - cell grows S - DNA synthesis G2 - cell grows further before mitotic phase
51
Prophase
Nuclear envelope breaks down Chromosomes coil Centrioles move to opposite poles Microtubules form mitotic spindles between centrioles
52
Metaphase
Chromosomes line up at equator Maximally condensed Attached to spindle by centromere
53
Anaphase
Chromosome breaks into 2 chromatids Sister chromatids separate at the centromere Spindle fibres contract and pull chromatids to opposite poles
54
Telophase
Chromatids reach poles and decondense Nuclear envelop forms
55
Cytokinesis
Cytoplasm splits
56
Function of Nucleus
Stores the cells DNA Maintains its integrity Facilitate transcription & Replication
57
Function of Mitochondria
Aerobic Respiration Produce ATP
58
Function of Chloroplast
Site of photosynthesis
59
Function of Rough ER
Protein synthesis
60
Function of Smooth ER
Lipid synthesis Transports carbs
61
What are lysosomes?
Sacs of digestive enzymes: protease, lipase, Lysozymes
62
Role of lysosomes
Hydrolyses WBC which have ingested phagocytes and bacteria Release enzymes by exocytosis Digest worn out organelles Breaks down dead cells
63
What are ribosomes?
Granules found in the cytoplasm of all cells
64
What are ribosomes made of?
rRNA + protein
65
What makes up the golgi body?
Flattened vesicles called cisternae Vesicles (membrane containers)
66
Role of golgi body
Recieves vesicles from the endoplasmic reticulum Packages and processes molecules
67
Golgi Vesicles
Pinched off from the golgi cisternae They move to the plasma membrane and release their contents
68
Plant cell wall Contains?
Contains Microfibrils
69
Algal cell wall Contains?
Cellulose and/or glycoproteins
70
Fungal cell walls contain?
Chitin & Glycoproteins Middle lamellae - borders adjecent cell walls and cements them together
71
Cell Vacuole
Single membrane called a tonoplast
72
Role of vacuole
Makes the cell turgid, giving support Fluid filled swap - contains minerals, salts, sugars, amino acids & wastes Provides a temporary food store
73
Role of cell membrane in prokaryotes
Controls what goes in and out of the cell
74
Role of Cell Wall in prokaryotes
Shape and support Stops cell bursting due to osmosis
75
What is the prokaryotic cell wall made up of?
Murein
76
Role of Capsule in prokaryotic cells?
Prevents drying out / dessication
77
Role of Pili in prokaryotes
Helps in attaching to surfaces
78
Type of ribosomes in prokaryotes
70S
79
Prokaryotic DNA
Contains genes for proteins requires Double helix No Histones for coiling Circular strand
80
Plasmid DNA
Contains extra genes which may be useful for bacterial survival
81
Stages of Cell fractionisation
1. Homogenisation 2. Filtration 3. Ultracentrifugation 4. Order of Fractionisation
82
Homogenisation
The tissue sample is homogenized using a blender to break the cells
83
Conditions for homogenisation
Ice cold Isotonic solution Buffered solution
84
Filtration
Tissue sample is filtered into tubes through a gauze, separating the larger components from the small organelles
85
Ultracentrifugation
Samples are span at increasingly higher speeds. Each tube balanced with another tube directly opposite Heavier organelles settle at the bottom Lighter organelles move towards the top
86
Electron microscopes
Uses a beam of electrons Allows higher resolution and resolving power More detail can be seen
87
What is needed for electron microscopes?
Vacuum to prevent electrons deflecting, meaning specimen must be dead
88
Antibody - Definition
Proteins produced by the immune system in response to foreign substances such as viruses or bacteria
89
Ways in which the immune system can respond to foreign cells
Lysozymes break down the foreign cells Phagocytosis of the foreign cells Production of antibodies that bind to the antigens and inhibit the functioning of foreign cells
90
Role of Plasma cells
Secrete antibodies
91
How are light chains connected to heavy chains in antibodies?
Disulphide bridges
92
Hinge protein
Connects the variable region to the constant region
93
Role of ELISA test
Tests for infections or allergies

Biology (7 decks)

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