Cell Biol Flashcards
(200 cards)
1
Q
Who came up with cell theory?
A
Shleider Schwann
2
Q
Who first grew isolated cells?
A
Harrison
3
Q
How do cells divide?
A
They double
4
Q
What are the core abilities of prokaryotic and eukaryotic cells?
A
Metabolism
Response to stimuli
Reproduction
Protein synthesis
5
Q
Who came up with the central dogma theory?
A
Francis Crick
6
Q
What is mycoplasma laboratorium?
A
A synthetic species of bacterium derived from a synthetic genome transplanted into a mycoplasma mycoides cell
7
Q
What are the limitations of central dogma?
A
One gene (one enzyme) is too simplistic
8
Q
What is redundancy?
A
Many genes play a small part in most functions
9
Q
What is the nucleus surrounded by?
A
Double membrane, nuclear envelope and nuclear pores
10
Q
What is the nucleus involved in?
A
Synthesis of mRNA, rRNA and tRNA
11
Q
What type of structure does DNA have?
A
Double helix
12
Q
What are the two pyrimidines?
A
Thymine and cytosine
13
Q
What are the two purines?
A
Adenine and guanine
14
Q
What is the nucleoplasm?
A
Proteins and DNA suspended in aqueous medium
15
Q
What is the nucleolus involved?
A
Ribosome synthesis
16
Q
What is nuclear lamina?
A
Forms a thin layer underlying and supporting the in nuclear membrane
17
Q
What are components of the nucleolus?
A
Fibrillar centre
Dense fibrillar component
Granular component
18
Q
What is the gene present of the Y chromosome in males?
A
SRY gene
19
Q
What is the dense version of chromatin?
A
Hetarochromatin
20
Q
What is the less dense version of chromatin?
A
Euchromatin
21
Q
Where are many active genes found?
A
Euchromatin
22
Q
What is a chromosome?
A
A single DNA molecule complexed with an equal mass of protein?
23
Q
What is DNA bound to to form chromatin?
A
Histones
24
Q
What are topoisomers?
A
Genetically identical but topologically different isomers
25
How many chromosomes are in a single diploid human cell?
46
26
What’s a typical size of a eukaryotic cell?
10-100 micrometers
27
What composes 70% of our cells?
Cytosol
28
What makes up the cytoskeleton?
Filamentous protein structues
29
What is a cytoskeletons function?
Establishing a cells shape
Determine intracellular location
Transport
Specialise functions
30
What are filaments held in?
Bundles/ networks by cross linking proteins
31
What else can the cytoskeleton be used for?
Generating cell polarity
32
What’s a typical example of a filament?
Actin
33
Functions of actin
Mechanical strength
Anchoring organelles
Helps cells divide in cytokinesis
34
What are microtubules?
Long straight hollow cylinders built by the assembly of dimers of alpha and beta tubuling
35
How does a positive end of microtubules grow?
By polymerising tubular dimers
36
What causes niemann-pick C disease?
Mutation in NPC1 or NPC2 genes
37
What are typical symptoms of niemann-pick C disease?
Dementia
Behaviour problems
Epilepsy
38
What are cilia and flagella constructed from?
Microtubules
39
What do secretory vesicles carry?
Cargo
40
How do secretory vesicles carry cargo?
Collect cargo in buds arising from membranes
41
What happens when vesicles membrane becomes part of plasma membrane?
The vesicles contents are lost out of the cell
42
What are the two types of secretory pathways?
Constitutive and regulated
43
Two types of endocytosis
Pinocytosis and phagocytosis
44
What do endosomes mature into?
Lysosomes
45
What is the internal pH of endosomes?
Acidic
46
What are lysosomes?
Membrane enclosed organelles containing over 50 degradation acid hydrolase enzymes?
47
What does endocytosis use to degrade materials?
Endosomes
48
What is autophagy?
Digestion of obsolete components of the cell
49
Give an example of neurodegenerative disorder?
NPC disease
50
Does the SER have ribosomes?
No
51
What is the SER involved in?
Calcium storage and lipid metabolism
52
What is the RER?
ER consisting of cisternae which have ribosomes on the outer surface?
53
What are proteins?
Amino acid joined by peptide bonds into long chains
54
What is the important pathway for protein maturation?
Sequence-> confirmation-> funciton
55
How is protein maturation achieved?
By forming bonds linking different regions of polypeptide chains e.g disulphide chains
56
What is methylation?
Attachment of methyl groups to amino acids
57
What is myristoylation?
Attachment of fatty acids to proteins
58
What is glycosilation?
Attachment of sugars to proteins
59
What is proteolytic cleavage?
Removal of sections of the polypeptide chains that are not required in the mature protein?
60
What causes cystic fibrosis?
Misfolding of the proteins CFTR
61
What is the Golgi apparatus?
A collection of flattened membrane bound cysternae and small spherical vescicles
62
What is bulk flow?
Smooth ER
Cis Golgi network
Cis Golgi stack
Medial Golgi stack
Trans Golgi stack
Trans Golgi network
63
What happens in the trans Golgi network?
Where stack break up into different transport vesicles that are dispatched to their final destinations
64
Wheee are phospholipids and fatty acids synthesised?
The ER
65
Where are glycolipids and sphyngomyelin synthesised?
Golgi
66
What makes up the phospholipid bilayer?
Hydrophilic head
2 hydrophobic tails
67
What’s cholesterol?
A major plasma membrane component?
68
What are non steroid hormone receptors?
Integral transmembrane proteins
69
What is solubilisation?
Disruption of lipid bilayer by detergents
70
What is the electrochemical gradient?
Combined force of a concentration gradient or charge gradient
71
What is symport?
Two substrates moved in the same direction
72
What is anti port?
Two substrates moving in different directions
73
What’s a glycolipid?
Consists of polysaccharide chains attached to lipids/proteins
74
Where a glycolipids located?
Extracellular surface of plasma membrane
75
What are lipid rafts?
Organising centres for membrane assembly, influencing membrane fluidity and membrane protein trafficking
76
Where is the glycoalyx located?
The cytosilic surface
77
What is the mitochondria?
Organelles that oxidise fuel molecules to generate ATP via oxidative phosphorylation
78
What are peroxisomes?
Enzyme containing organelles which produce hydrogen peroxide
79
What is the role of mitochondria in metabolism?
Oxidative decarboxylation and ETC
80
6 criteria of living organisms
Organised structures
Metabolism
Growth
React to stimuli
Reproduction
Evolve
81
3 domains of life
Archea
Eubacteria
Eukaryotes
82
What are archea?
Microbes that live in extreme environments
83
What is the cell cycle?
The stages that cells have to progress through in the mechanism of asexual reproduction.
84
What is the cell cycle made up of?
Mitosis and interphase
85
Types of cells
Singular and multitude
86
What is a singular cell?
Function and survive independently
87
What are multitude cells?
Cells that do not survive once separated
88
What is retinoblastoma?
Growth inhibitory TS protein
89
What is cell fate?
Divide
Differentiate
Die
90
What is mitosis comprised of?
Prophase
Pro metaphase
Metaphase
Anaphase
Telophase
91
What happens during interphase?
Cell increase in size
Generates 2 chromatids
Centrosome is duplicated
92
What is the centriole?
A hollow cylindrical, organelle
93
What happens during prophase?
Duplicated DNA condense to form 2 sister chromatic
DNA becomes visible to light microscope
Cenreikwa more to opposite ends of poles
Cycling and cyclin dependent kinases are activated
94
What happens during pro metaphase?
Complete dissolution of NM
Formation of spindle structure
Proteins attach to centromeres creating the kinetocjores
Kinetochores attach to the spindle microtubules and begin active movement
95
What happens during metaphase?
Microtubules form spindle pole body
Spindle fibres align chromosomes along equator
2 members of sister chromatid attach to a microtubules
96
What happens during anaphase?
Sister chromatids move outward
Separation results in the formation of two daughter chromosomes
Pulled apart and slowly move towards the spindle pole
Kinetochore tubules get shorter and spindle pole moves outwards
Results in chromosome separation
97
What happens during telophase?
Chromatids arrive at opposite ends of each pole
New M! Form around daughter nuclei through the action or phosphatases which remove the phosphate groups
Chromosomes begin to disperse
Spindle fibres begin to disperse
Beginning of cytokinesis
98
What is cytokenesis?
Cellular segregation
99
What happens during cytokenesis?
Cytoplasm divides into 2 by a contrile ring of Actin and myosin filaments
End of cell division generations two daughter cells
100
Who discovered mitosis?
Walther Fleming
101
What is tissue culture?
Method of studying the behaviour of a cell
102
Why do we use tissue culture?
Cheaper
Reliable
Reproducible
Ethically acceptable
103
What did we use before tissue culture?
Bacteria cell culture
104
Why don’t we use bacterial cell culture anymore?
They failed to be representative models of humans and higher mammals and their respective diseases
105
Three types of tissue culture
Organ culture
Primary explants
Cell culture
106
Advantages of organ culture
Retain cell- cell interactions
Differentiated
107
Disadvantage of organ culture
Heterogenous
Poor growth
Cannot be efficiently propagated
Poor sample reproducibility
Large amount of material requirements
High maintenance costs
108
What cell is adherent?
Epithelial
109
What cell is non-adherent?
Blood
110
What is the major purpose on senescence?
Evolutionary aspect in the cellular prevention of cancer
111
Common requirements of primary cell culture
Fat and necrotic tissue removes
Finely chopped tissue
Enzymes used for disaggregation should be removed
High cell concentrations are required
Preferably embryonic/ tumour tissue
112
How to determine cell concentration?
Counted using a haemocytometer and trypan blue
113
What does trypan blue do?
Indicates cell membrane permeability
114
What are quiescent cells?
Are in a reversible cell cycle arrest and able to respond to mitosis stimuli
115
What are optimum conditions for cell growth?
7.5 pH
37°c
Serum
Gas phase
Osmolality
116
Types of cell culture
Finite (normal)
Continuous (abnormal)
117
Advantages of using primary cell culture system
Differentiated into other cell types
Relevant to normal tissue
Provide for better models of investigation of disease
118
Disadvantages of using primary cell culture
Finite growth span
Extremely sensitive to surroundings
Expensive to maintain
Heterogenous
119
What happens to cells when they reach 100% confluency?
Undergo cellular stasis and are quiescent
120
How do cells interact with each other?
Cell junction proteins
121
What are the cell junction proteins?
Tight junctions
Adheren junctions
Desmosomes
Gap junctions
Focal adhesions
Hemidisomes
122
What are cellular signals for quiescence and how are these signals propagated in the cell?
Structural proteins which are integral to the cell-cell interaction
123
Components of extracellular matrix
Fibrous structural proteins
Water hydrated gels
Adhesive glycoproteins
124
What are the different stem cells?
Totipotent
Pluripotent
Multipotent
125
Why do stem cells continually divide?
Continusted presence of telomerase
126
What the cell separation techniques?
Adherence
Density
Antibody
127
What does adherence use?
Gravity
128
What does density use?
Centriguation of total blood cells
129
How to isolate stem cells
Using cellular surface protein markers?
130
What does antibody use?
Fluorescent and magnetic
131
What is a nucleoside?
Base and deoxyribose
132
What is a nucleotide?
Nucleoside and phosphate
133
What is a nucleid acid?
Polymer of nucleotides
134
What is a pyrimidine?
A nitrogen containing a 6 member end single ring compound
Cytosine and thymine/uracil
135
What is a purine?
A nitrogen containing a 9 member end single ring compound
Adenine and guanine
136
How are nucleotides joined?
Phosphodiester bonds
137
What does the 5’ end contain?
Free polar phosphate group
138
What does the 3’ end contain?
A free polar hydroxyl group OH
139
What is the sense strand?
5’-3’
140
What is the anti sense strand?
3’-5’
141
What are oligonicleotides?
Short nucleic acid chains
142
What are polynucleotides?
Much longer chains
143
Where is mRNA found?
Nucleus
144
Where is rRNA found?
Cytoplasm
145
Where is tRNA found?
Cytoplasm
146
What is semi conservative replication?
Each daughter DNA duplex contains 1 strand from parent molecule and one newly synthesised DNA strand
147
What is semi-discontinuous replication?
Only one leading strand is synthesised continuously
148
What is semi-discontinuous replication?
Only one DNA strand is continued
149
What is transcription?
Begins when an enzyme call RNA polymerase attaches to the template DNA strand and begins to catalyse the production of complementary RNA
150
What are polymerases?
Large enzymes composed of a dozen subunits and when active on DNA they are usually complexed with other factors
151
What are the 3 types of RNA polymerase?
RNA pol I
RNA pol II
RNA pol III
152
What does RNA pol I do?
Transcribes the genes that encode most of the rRNAs
153
What does RNA pol II do?
Transcribes the messenger RNA
154
What does RNA pol III do?
Transcribes the genes for one small rRNA
155
What is transcription?
Process by which DNA is copied to mRNA by RNA molecules
156
What is splicing?
Removal of intron sequences
157
What are stop codons?
TAA, TAG & TGA
158
What is the start codon?
ATG
159
What do all protein sequences begin with?
Methionine
160
How is PCR used in medicine?
Carrier testing for genetic diseases
And prenatal diagnosis
161
What are the types of artificial cloning?
DNA/gene cloning
Reproductive cloning
Therapeutic cloning
162
What is DNA/gene cloning?
The transfer of a DNA fragment of interest from one organism to a self replicating genetic element such as a bacterial plasmid
163
What is reproductive cloning?
A technology used to generate an animal that has the same nuclear DNA as another currently or previously existing animal
164
What is therapeutic cloning?
Creating a cloned embryo to produce embryonic stem cells with the same DNA as the donor cell
165
What is pharmacogenetics?
The study of how genes affect a persons response to drugs
166
What are genes?
Units of hereditary that contain information that determine specific traits
167
What are alleles?
Variations of the same gene
168
What is the inheritance pattern of alleles controlled by?
Meiosis
169
What is meiosis?
The process of cell division during gamete formation
170
What is independent assortment?
The segregation of alleles of one gene is independent of the segregation of the alleles of another gene
171
What is a dihybrid cross?
Mating between two strains differing in two characteristics
172
What are the two main functions of meiosis?
Produces recombinant chromosomes or a mixture of genetic information from both parental chromosomes
Halves the number of chromosomes in a cell
173
What is a rare example of genetic linkage in humans?
Nail-Patella syndrome and ABO blood groups
174
When will recombination frequency be low?
If two genes are very close
175
When will recombination frequency be high?
If two genes are very far apart
176
What are autosomal recessive diseases?
PKU, sickle cell anaemia, albinism and CF
177
What are autosomal dominant diseases?
Huntingtons disease, colour blindness and haemophiliacs
178
What are X linked recessive disorders?
Colour blindness and haemophilia
179
What are X linked dominant disorders?
Hypophosphotemia
180
Frequency of an allele question
Number of copies of the allele/ number of copies of all alleles at the locus
181
What is the Hardy-Weinberg equation?
P^2+2pq+q^2=1
182
What is a genotype?
The inherited alleles of an individual
183
What is a phenotype?
The physical characteristics of an individual
184
What are two types of variation in human chromosomes?
Changes in chromosome structure
Changes in the number of chromosomes in a cell
185
When does duplication occur?
When a chromosome segment is duplicated by mistake during chromosomal replication prior to cell division
186
When does deletions occur?
When a fragment of chromosome is missing and can cause severe abnormal traits
187
What is inversions?
When sequence of genes on a chromosome is reversed
188
What is translocations?
Movement of a chromosomal segment from one chromosome to another
189
What are diseases associated with translocations?
Leukaemia and Down’s syndrome
190
What is polyploidy?
Three or more sets of the same chromosomes
191
What is aneuploidu?
An increase or decrease of the number of individual chromosomes
192
Examples of aneuploidy:
Nullisomy
Monosomy
Trisomy
Tetrasomy
193
How does aneuploidy occur?
Caused by two homologous chromosomes not separating during meiosis
194
What causes Down’s syndrome?
Extra copy of chromosome 21
195
What is Jacob’s syndrome expressed as?
XYY
196
What is Klinefelters syndrome expressed as?
XXY
197
What is Trisomy X expressed as?
XXX
198
What is Turner’s syndrome expressed as?
XO
199
What causes Edwards syndrome?
An extra copy of chromosome 18
200
Does cell division result in daughter cells during meiosis?
No
