Brainscape's Knowledge GenomeTM


Top Flashcards (Certified)
All Flashcards

LCB > LCB1 > Flashcards

LCB1 Flashcards

1
Q

Why is microbiology important in veterinary medicine?

A
  • Understand disease.
  • Recognise emerging diseases
  • Improve the control of known infections to improve prevention and to reduce spread
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What are the different groups of microorganisms in order of size (largest to smallest)?

A

Fungi (5micrometers), bacteria (1-5 micrometers), virus and prions (300 to 20 nanometers)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What are the basic structural properties of bacteria?

A

Cell membrane, capsule, cell wall, single haploid chromosome (circular), ribosomes and plasmid

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Describe the bacterial genome

A

Consists of a haploid circular chromosome which contains essential and core genes (which define bacteria) and contains plasmid (small circular independent DNA)

  • plasmid not present in all bacteria
  • plasmid contains partitions genes involved in cell division
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What is a nucleoid?

A

DNA in the chromosome organised into a protein complex

No nucleus - DNA packed closely by supercoiling using DNA gyrase

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What are the function of histones?

A

Further pack the DNA into protein complexes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What type of ribosomes are present in eukaryotes?

A
  • Larger ribosomes
  • 80s
  • 40% rRNA 60% protein
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What type of ribosomes are present in prokaryotes?

A
  • Smaller ribosomes
  • 70s
  • 60%rRNA 40%protein
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What are the different groups of bacteria?

A

Gram negative, gram positive, acid fast and mycoplasmas

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What are the structural features of gram negative bacteria?

A

Lipopolysacharides, double membrane, thinner capsule, lipoproteins, thinner peptidyglyocan layer

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What are the structural features of gram positive bacteria?

A

Thicker capsule, thicker peptidyglyocan layer, single membrane

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What are the structural features of acid fast bacteria?

A

Mycolic acids, D-galactose in cell wall, phylogenetically related to gram positive
Resist decolourization by acid-alcohol so remain and stained red the colour of the first stain in acid fast staining (carbol fuchsin).

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Describe the gram stain

A

1) Crystal violet (dye-purple)
2) Iodine (mordant)
3) Alcohol (decolourisation)
4) Safranin (counterstain)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Describe the acid fast stain

A

1) Ziehl Neelsen carbofuchsin added to fusion slide and apply with heat
2) Acid alcohol added and washed with water
3) Counter stain added (methylene blue) and washed with water

Acid fast bacteria retain red colour, other blue

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Describe some bacterial differences within different bacteria

A
  • LPS outer memrane of gram negative bacteria
  • capsules- protection against dessication, adherences and interefere with phagocytosis
  • flagella: used for motility
  • pili/fimbrae: adhesion function
  • endospores
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What are the modes of motility in flagella

A

RUNS-straight lines

TWIDDLES- move on spot to rotate

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

What are endospores?

A

Highly resistant bodies produced by bacteria which survive adverse conditions

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

How are endospores developed?

A

1) Vegetative cell trigger to form spore in mother –> assymetric division and spore forms on one side
2) developing of spore coat –> synthesis of dipicolonic acid and accumulation of Ca2+
3) release of endospore due to cell lysis of mother
4) triggered to germinate by activation of heat, excretion of Ca2+

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

What are the 4 classes of lipids?

A

Fatty acids, triglycerides, phospo and sphingolipids, steroids

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

Which fatty acid has one or more carbon to carbon double bonds

A

Unsaturated fatty acids

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

Describe the structure of different fatty acids

A

Triaglycerol- glycerol and 3 fatty acids
Glycophospholipids- glycerol, 2 fatty acids, phosphate and polar head group
Sphingolipids- 2 sphingospine, fatty acid, phosphate, polar head group
Glycolipids- 2 sphingosine, fatty acid, monosaccharides

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

Give examples of hydrophilic and hydrophobic groups

A

Hydrophillic- phosphate, oxygen, carbon dioxide, nitrogen

hydrophobic tail- fatty acid tail

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

What are the functions of cell membranes

A

Protection, stability, adherence,

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

What is sphingomyelin lipidosis

A

Definciency of sphingomyelinase –> accumulation of sphingomyelin –> lysosmal catabolism

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
What is the role of cholesterol?
Moderator of membrane fluidity. Makes structure more rigid. Interacts and immobilises ends of phospholipid hydrocarbon chains. Prevents crystillisation (phospholipids coming together)
26
What is the function of an ABC transporter?
Defense mechanism against harmful substances. ATP binding casssette via active transport. Composed of P-glycoprotein.
27
Why do you need to be careful when administrating antibiotics to border collies?
Border collies have a deletion mutation with MDR1 gene (frame shift mutation) resulting in a premature stop codon in MDR1 which results in a non functional P-glycoprotein.
28
What are lipid rafts and what are their functions?
Formed by interaction of lipids Control membrane composition External side= receptors Cytoslic side= intracellular signalling
29
Explain the Fluid Mosaic model
The fluid part represents the fluidity of the phospholipid bilayer composed of the hydrophobic tail. The mosaic part represents the patchwork of proteins in the phospholipid bilayer. The phospholipids move about more rapidly than larger proteins
30
What is the function of the fluid mosaic model?
It is a barrier. | Allows flexible change in shape/membrane composition
31
Explain the steps in bleaching
1) Membrane protein of interest is flourescently labelled 2) Laser beam bleaches specific area 3) Flourescent intensity develops as bleached molecules move away
32
What is Chromatin?
Linear DNA and proteins (histones) arranged in the chromosome
33
What are nucleosomes?
Building blocks of chromatin. Composed of 8 histone proteins. Nucleosomes separated from each one by linker DNA
34
Describe the organisation of DNA
DNA is organised into chromosomes. Within a chromosome you have chromatin which is made up of nucleosomes and histone proteins.
35
Describe differences between prokaryotic DNA and eukaryotic DNA
Prokaryotic DNA is organised into a haploid chromosome, and can sometimes be organised into a plasmid. Eukaryotic DNA is organised into a diploid/homologous chromosomes.
36
Describe DNA replication in prokaryotes
1) Double stranded DNA separated into parental (template) strand and daughter (new) strand 2) Replication occurs at replication fork 3) 2 daughter cell /DNA molecules form
37
Describe DNA replication in eukaryotes
1) Double stranded DNA separated into parental and daughter strand 2) replication occurs in opposite direction between 2 new strands at replication fork 3) 2 daughter DNA strands formed
38
What is the function of DNA topoisomerase?
Unwinds double helix by cutting and resealing tangled DNA
39
What are telomeres?
- GGGTTA repeats - forms longer DNA- repeats on 5' - 3' FILLED by DNA synthesis
40
What are the different types of damage DNA can undergo?
``` Spontaneous damage: -glycosidic link binding purines to sugars is unsrtable and bases break off --> C + A deaminate to U + hypoxanthine Chemical damage: -o2 free radicals -UV light and carcinogens ```
41
How does DNA repair itself?
Via DNA repair nucleases: recogniion and removal of area then via DNA polymerase on opposite strand and DNA ligase
42
What is the genome composed of?
Exons- coding Introns- non coding Open reading frame ORF- determine translation 5' contains promoter- where transcription proceeds Repeated sequences- transposons, macrosatelites, microsatelites
43
What are transposons?
Lines- long interspersed repeated sequences Sines- short (aluin in humans) Function unknown
44
Name the different single repetitive DNA sequences
Macrosatellites- composed of 5-500 bases and repeated MILLIONS of times -located in chromatin Microsatellites- cmposed of 2-6 base pairs and repeated 12-40 times -used as genetic markers to identify unique traits
45
Describe the process of transcription
1) DNA helicase breaks H-bonds between bases exposing the template strand 2) RNA polymerase joins free complementary nucleotides 3) transcription occurs from 5' to 3' 4) RNA polymerase reaches a stop codon and forms pre-mRNA 5) pre mRNA spliced to remove introns
46
What are s-values
Rate of sedimentation in ultracentrifuge. The greater the S valie the larger the rRNA
47
What occurs during mRNA processing?
- capping on 5' --> by addition of 7-methylguanosine - polyadenylation at 3' --> poly(adenosine) tail to make mRNA in nucleus occur - introns removed --> splicing occurs in spliceosomes
48
What happens within the promoter region?
- On the end of DNA. Includes a TATA box - Upstream of transcription start site - Controls CAAT + GG boxes - Acts a as mediator: binds RNA polymerase
49
What happens within the enhancer region?
- Generally upstream | - increases amount of transcribed RNA
50
What are the structural modifications of chromatin needed to activate the promoter region?
- Chromatin remodelled via nucleosome - histone modifications - modification of DNA via methylation of C --> CG nucleotide at promoter --> represses gene expression
51
Explain process of gene expression: activation of transcription
1) nucleosomes are removed, revealing the promoter 2) transcription factors bind to promoter DNA (+enhancer if required) 3) Mediator proteins complete initation event 4) initiation complex recruits RNA polymerase 5) many points where control over rate of initation of mRNA transcript is possible
52
Explain process of gene expression- down regulation
1) Termination singal in gene-termination + releases transcripts 2) transcription factors inactivated 3) dephosphorlyation 4) transcription terminates
53
What are the different types of mutations?
Mis-sense mutation- insertion of incorrect amino acid Frame-shift mutation- assembly abnormal sequence of amino acids: STREPTOMYCIN + RETROVIRUS Pre-mature termination - non sense mutation- single base change could code for stop codon
54
What is the structure of a tRNA molecule?
``` Clover leaf structure 80 nucleotide in length At 3' amino acid receptor D loop, t loop Anti-codon (GAA) opposite amino acid receptor ```
55
What is Wobble hypothesis?
First 2 bases confer most of specificity
56
Explain how tRNA-amino acid complex formed?
1) Adenylation of amino acid - addition of AMP | 2) Transfer of amino acid to tRNA
57
What is the mechanism for protein synthesis?
1) INITIATION ribosome composed of large and small subunits mRNA scanned by small subunit and bound by initiator tRNA Recruitment of initiation factors tRNA binds to AUG on mRNA --> GTP binding/hydrolysis 2) ELONGATION CYCLE Positioning of aminoacyl on tRNA in A site (ribosome) Peptide bond formation Translocation 3) TERMINATION - UAA, UAG, UAC GTP hydrolysis alters ribosome function and ribosome dissociates
58
What antibiotics target small sub units?
Tetracycline, streptomycin, hydromycin B
59
What antibiotics target large sub units?
Chlorampheniol, erthrymycin, streptogramin B
60
What are the post-translational modifications?
- Proteolytic cleavage - disculfide bond formation - glycosylation/hydroxylation/phosphorylation - lipophillic modification- add a lipid
61
Name the bonds that stabilize proteins
Covalent, non covalent (ionic, hydrogen and van der waals)
62
What is the structure of an amino acid?
- R side chain (variable) - Carboxyl group - Amino acid group
63
What enables folding of a protein?
- Covalent bonds allow free rotation = flexible (rotation about C-C + C-N - Non covalent bonds in side chain do not allow roation - polar molecules form bonds with +'ve dipole H+ in H2O forming a non-covalent hydrogen bond
64
What is the primary structure of a protein?
- Linear chain of amino acids - C backbone- non polar - 6 classes of R side chains - peptide bonds forming polypeptide
65
What is the secondary structure of a protein?
- coiling/pleating of polypeptide chain - alpha helix- side chains extending outwards - beta pleated sheets- side chains point in opposite directions - connected by beta turns or omega loops
66
What is the tertiary structure of a protein?
- secondary structure folded into a 3D shape - hydrophobic interactions on inside (tail) - hydrophillic head on outside - globular- spherical, soluble i.e Hb - fibrous- long filamentous, insoluble i.e. collagen
67
What is the quaternary structure of a protein?
Several polypeptide chains
68
What is a structural domain?
An element of overall structure within a protein which forms a discrete, self contained section of polypeptide e.g. calcium binding domain
69
What is a protein motif?
Sequence of a small number of amino acids unrelated to structure Can make up a domain
70
What is the generation time?
The length of time required for one complete cycle of cell division - for a bacterial cell to divide into 2 daughter bacterial cells
71
How can you measure the growth of bacteria?
- Optical density (absorbance) - Microscopically: direct counting - Colony counting: serial dilutions, spread plate, pour plate, mile-micra, membrane filtration
72
What is a psychrophile?
Grow in temperature below 25 degrees Celsius
73
What is a thermophile?
Bacteria that grow in temperatures above 40
74
Where does a chemoheteroptroph get its energy and carbon from?
Energy- oxidase chemical compounds | Carbon- organic compounds
75
Where does a chemoautotroph get its energy and carbon form?
Energy- oxidase in organic chemical compounds | Carbon- CO2
76
What is the difference between fastidious and non fastidious bacteria?
Fastidious bacteria require specific supplements to grow
77
What are examples of nutrition for bacteria and where do they get it from?
Carbon- glucose N2- peptides and amino acids Phosphates- nucleic acids and compounds with energy rich bonds Sulphates- form sulfur containing amino acids Mg, K, Ca, Fe- co-factors in enzymes and processes
78
How can you preserve an organism?
- Sub culturing- labour intensive - Freeze drying- lyophilisation - Freeze with cryoprotection (DM or glycerol)
79
What is the structure of the cytoskeleton?
Microfilaments- actin Intermediate filaments-keratin family Microtubules - alpha and beta tubulin
80
What is the role of the cytoskeleton?
- Maintenance of cell shape- mechanical support - Movement - Contraction - Internal organisation i.e. in chromosomes
81
Describe the self assembly of microtubules
B tubulin + alpha tubulin --> protofilament --> microtubule
82
What are the 2 molecular motor proteins that travel along MT?
Kinesin (- to +) | Dynein (+to -): cytoplasmic dynein and axonal, beating of cilia and flagella, fastest
83
What are the types of axonal transport?
Anterograde by Kinesin - provides synapse region with proteins Retrograde by dynein- recovers material for lysosomal degradation
84
What is the structure of actin?
- Helical polymers - polarised - used in muscle contaction - actin monomer exists as G-ACTIN - filamentous polymer exists as F-ACTIN
85
What are the functions of actin filaments (microfilaments)
- surface crawling - produce stable projections e.g. microvilli - form contractile bundles
86
How does actin and tubulin produce polar filaments?
Actin binds to ATP and Tubulin binds GTP - if ATP/GTP on end = addition of subunit - if ADP/GTP on end= loss of subunits by dynamic instability and treadmilling
87
Explain the process of dynamic instability
It is the process of microtubulels depolymerising very quickly composing of GDP - GTP = 'CAP' dimer on (+) - microtubule depolymerises and polymerises on (+) end - can occur in microfilaments with actin
88
Explain the process of treadmilling
[G-actin] > Cc of barbed (+) end +
89
What is the self assembly of intermediate filaments
Monomer --> coiled coiled dimer --> staggered tetramere of 2 coiled coiled dimers antiparallel --> 2 etrameres packed together --> many tetrameres packed together in a helical array (16 dimers)
90
What is the structure of cilia and flagella?
Axoneme ( 9 outer doublet microtubules surrounding pair of central microtubules) - CLILA: bending of axoneme causes movement of cilia - dynein
91
Explain 3 step process of surface crawling
1) PROTRUSION- actin rich structures pushed to the front of cell 2) ATTACHMENT- adhesion to substratum via focal contact--> slows movement --> actin polymerisaation at (+) and protrudes lamellipodium 3) TRACTION- contraction generated by myosin motor proteins at rear and propels body cell forward

LCB (3 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2025 Bold Learning Solutions. Terms and Conditions