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DAT Biology > CH.8 Microscope and Lab Techniques > Flashcards

CH.8 Microscope and Lab Techniques Flashcards

(75 cards)

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1
Q

What is fixation in microscopy?

A

Fixing or ‘sticking’ the cells onto a microscope slide

Fixation is important as it preserves the cells in a life-like state.

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2
Q

What does staining do in microscopy?

A

Adds color to cells to emphasize cell structures.

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3
Q

What is a consequence of the staining process?

A

The staining process usually kills cells.

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4
Q

What is optical microscopy?

A

involves shining light on a cell to observe its large organelles . It can view living and non living cells.

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5
Q

What is electron microscopy?

A

Shoots a beam of electrons at the sample. Cannot observe living cells.

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6
Q

What is a key advantage of electron microscopy over optical microscopy?

A

It gives higher resolution images.

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7
Q

What is a stereo microscope?

A

A type of optical microscope that offers low magnification to observe the surface of live samples.

(think stereo = old)

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8
Q

What is a compound microscope used for?

A

It is an optical microscopy, To view one-cell thick, live samples.

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9
Q

What is the main feature of phase contrast microscopes?

A

They can view thin samples of live cells with good contrast. Can cause phase shift and a halo effect.

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10
Q

f you wanted to observe a living plant cell, what type of microscope would you use to observe it?
A. Optical Microscope
B. Electron Microscope

A

A. Optical Microscope

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11
Q

What does a dichroic filter do in fluorescence microscopy?

A

Allows specific wavelengths of light to be reflected onto the sample.

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12
Q

What is the purpose of confocal laser scanning microscopy?

A

To observe chromosomes during mitosis and overcome artifacts of fluorescence microscopy.

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13
Q

What is dark field microscopy used for?

A

To view unstained samples of live cells by increasing contrast.

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14
Q

What is the main disadvantage of dark field microscopy?

A

It has low light intensity.

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15
Q

What is scanning electron microscopy (SEM) used for?

A

To visualize high-resolution 3D images of the dehydrated sample’s surface.

SEM = SURFACE

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16
Q

What distinguishes cryo-scanning electron microscopy (cryo-SEM) from regular SEM?

A

The sample is frozen in liquid nitrogen instead of dehydrated.

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17
Q

What does transmission electron microscopy (TEM) visualize?

A

High-resolution 2D images of a sample’s internal structures.

TEM= TWO

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18
Q

Which type of microscopy results in images with good contrast without fixing, staining, or tagging?

A

Phase Contrast Microscopy and Dark Field Microscopy.

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19
Q

What is a Hemocytometer?

A

A gridded slide that counts cells, to find the concentration of cells in the fluid.

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20
Q

What is the purpose of Colony Forming Units?

A

Estimate the number of cells plated on a growth medium.

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21
Q

What is the purpose of Automated Cell Counting?

A

Estimate the number of cells by observing flow of electricity in solution.

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22
Q

What occurs during the Lag Phase of bacterial growth?

A

Bacteria are adapting to growth conditions; no growth.

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23
Q

What is characterized by the Log (Exponential) Phase?

A

Number of cells and rate of growth doubles; linear ascending growth.

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24
Q

What happens during the Stationary Phase?

A

Growth rate = death rate due to growth-limiting factors.

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25
What is the Death Phase in bacterial growth?
Bacteria die due to lack of nutrients and environmental factors.
26
What is Cell Fractionation?
Process where cell contents are separated into fractions by centrifugation. they are centrifuged by their mass, density, or shape
27
What is Differential Centrifugation?
process where cells are split open to separate components based on density. (small particles go to the top, large particles go to the bottom.)
28
What is the order of organelles from most dense to least dense?
* Nuclei *chloroplasts * Mitochondria *lysosomes *peroxisomes * microsomes * Ribosomes
29
What is Density Centrifugation?
Separates cell components of original homogenate in a single centrifugation cycle.
30
What is Karyotyping?
counts the number of chromosomes, detects abnormalities. (down syndrome)
31
What are the two types of DNA sequencing?
* Sanger Sequencing (older) * Next Generation Sequencing
32
What is the purpose of Single Nucleotide Polymorphism (SNP)?
Serve as markers for genes that cause disease.
33
What is Recombinant DNA?
Produced when DNA fragments from different sources are joined together.
34
What are Sticky Ends in DNA?
Have unpaired nucleotides; make it easy for complementary ends to hybridize.
35
What are Blunt Ends in DNA?
paired nucleotides; harder to hybridize.
36
What are Restriction Fragment Length Polymorphisms (RFLPs)?
non coding DNA from restriction enzymes **used to compare and contrast DNA between individuals**. (twins have the same RFLP)
37
What is the purpose of CRISPR?
Used by bacteria to target and remove sequences from invading pathogens ## Footnote Scientists have adapted this mechanism to edit genomic regions of interest by adding or deleting specific sequences.
38
What is PCR?
The amplification DNA. (millions /billions of copies)
39
What are the required components in a container for PCR?
* DNA primers * Taq polymerase (heat resistant DNA polymerase)
40
What are the three main steps of PCR?
1. Denaturation 2. Primer annealing 3. Elongation
41
What happens during the Denaturation step of PCR?
Container is heated to ~95°C, splitting DNA double helix into separate single strands
42
What occurs during the Primer Annealing step of PCR?
Temperature is lowered to ~65°C, allowing DNA primers to stick to single DNA strands
43
What is the function of Taq polymerase in PCR?
During Elongation it uses single DNA strand as template to add nucleotides to the 3’ end of DNA.
44
What do restriction enzymes do?
Cut DNA at palindromic sequences to produce sticky or blunt ends
45
What is DNA fingerprinting?
Uses RFLPs and STRs to identify individuals
46
True or False: PCR requires the use of cells.
False
47
What methods can check for the gene of interest in bacterial cloning?
* Antibiotic resistance * Color change method
48
What is the purpose of Gel Electrophoresis?
Separate DNA or RNA or proteins fragments by charge and size
49
What is the role of agarose gel in Gel Electrophoresis?
DNA is loaded into wells, and an electric field is applied to separate fragments
50
What happens to negatively charged DNA in Gel Electrophoresis?
It is attracted to the positive end of the gel = bottom & vise versa negative = top
51
What is Southern Blotting used for?
To identify fragments of a known DNA sequence in a large population of DNA
52
What is Northern Blotting?
Technique used to identify fragments of a known RNA sequence using RNA probes
53
What is the purpose of Western Blotting?
Used to quantify the amount of target protein in a sample
54
What does SDS-PAGE do?
Separates proteins by mass using sodium dodecyl sulfate
55
What is the purpose of ELISA?
Used to determine if a specific antigen exists in a person
56
What is the Pulse Chase Experiment designed to study?
How proteins move through a cell
57
Fill in the blank: The process of making competent bacterial cells can involve _______.
Electroporation or Heat shock
58
Fill in the blank: Antibiotic resistance is used to check if the _______ is successfully transformed into the bacterial cell.
gene of interest
59
What does the color change method indicate in bacterial cloning?
If target gene successfully inserts into cell, the cell turns white
60
What is genomics?
The study of all genes present in an organism’s genome, including gene structure, function, and interaction ## Footnote Genomics encompasses various techniques and technologies for analyzing genomes.
61
What is a genomic library?
A way to store all the DNA of an organism’s genome ## Footnote It is created by cutting the genome into fragments and cloning them.
62
How are fragments cloned in a genomic library?
Using PCR and DNA ligase to insert cloned fragments into plasmids ## Footnote Plasmids help preserve the DNA fragments for further study.
63
What is the purpose of DNA microarrays?
A chip containing thousands of DNA probes. To determine which genes are expressed (active ) (DNA → mRNA) ## Footnote The result is visualized through fluorescence emitted during hybridization.
64
What is the first step in the DNA microarray protocol?
Isolate specific type of cell from sample ## Footnote This ensures that the analysis is conducted on the relevant cell type.
65
What do transgenic animals help researchers identify?
The function of a gene ## Footnote They also enable the mass production of certain medications.
66
What is reproductive cloning?
The process of taking a somatic cell from an animal and producing an exact genetic copy of that cell ## Footnote It involves reverting the somatic cell to a totipotent state.
67
What does totipotent mean?
cells that evolve and can become a complete organism. ## Footnote This is the highest level of cell potency.
68
What are the three germ layers that pluripotent cells can differentiate into?
Endoderm, mesoderm, and ectoderm ## Footnote Pluripotent cells cannot develop into an entire organism.
69
What did Dolly the Sheep demonstrate?
That multipotent somatic cells could be reverted to totipotency ## Footnote Dolly was the first mammal cloned from an adult somatic cell.
70
What is the purpose of chromatography?
To separate liquids in a mixture by solubility ## Footnote Chromatography is a key technique in biochemistry for analyzing compounds.
71
What is the purpose of Fluorescence Recovery After Photobleaching (FRAP)?
To see how and where biomolecules are moving in a live cell ## Footnote FRAP allows for the observation of molecular dynamics in real-time.
72
What does Fluorescence Lifetime Imaging Microscopy (FLIM) measure?
Concentration of various ions, molecules, and gases in a cell ## Footnote FLIM uses fluorescent lifetimes to provide quantitative data.
73
What are knockout mice?
Mice with a selected gene of interest that is ‘knocked out’ (deactivated) by recombinant DNA technology ## Footnote They are used to study gene function and disease models.
74
If you were performing a four step 1:1000 serial dilution of a bacterial culture, what would the final concentration and dilution factor be?
10 ^ -12 , 10 ^ 12 4 x (number of zeros) = 12 ## Footnote Dilutions are commonly used in laboratory settings for various assays.
75
What is the purpose of DNA microarrays?
D) Determine gene expression within the cell

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