Biology Lab Midterm: Neurobiology, ELISA, Bradford Assay, and PCR/Alu Analysis

Vocabulary practice flashcards covering brain anatomy, Alzheimer's pathology, experimental design, micropipetting, ELISA, the Bradford protein assay, gel electrophoresis, and PCR analysis of the Alu PV92 polymorphism.

Alzheimer's Disease

A progressive neurodegenerative disease characterized by misfolded proteins ($A\beta$ and Tau).

Brainstem

The region of the brain that regulates heart beat, blood pressure, and breathing.

Frontal Lobe

The brain lobe responsible for decision making and higher-order processing.

Cerebellum

The brain structure responsible for motor function and movement.

Temporal Lobe

The brain lobe containing the hippocampus that receives information from it and is involved in memory.

Hippocampus

The brain structure responsible for the formation of new memories.

Entorhinal Cortex

A brain area that communicates with the hippocampus, transfers information between the hippocampus and other brain areas including the frontal lobe, and is important for memory consolidation.

$A\beta$ (Amyloid Beta)

A small peptide produced from APP and cut by proteases into the extracellular space that interferes with protein transport and mitochondrial activity.

Tau

A protein that binds to microtubules and acts like railroad tracks inside the neuron axon for material transport.

Cerebrospinal Fluid (CSF)

A clear liquid that surrounds the brain and spinal cord and helps to maintain homeostasis.

Biomarker

A measurable biological characteristic that can indicate a disease or body condition.

Wash Buffer

A solution containing a blocking compound used to saturate the plastic surface in assays.

Positive Control

A control group in an assay that contains the target antigen and turns blue.

Negative Control

A control group that does not contain the target antigen and produces no color.

Independent Variable

The variable in an experiment that is intentionally changed by the experimenter.

Dependent Variable

The variable measured as an outcome or result of the experimental change.

Null Hypothesis

A hypothesis stating that there is no effect.

Serological Pipette

A pipetting instrument used for liquid volumes $< 50\,\text{mL}$, utilizing pumps colored red ($25\text{--}50\,\text{mL}$), green ($5\text{--}10\,\text{mL}$), and blue ($1\text{--}2\,\text{mL}$).

Micropipette

A precision instrument used to measure liquid volumes $< 1\,\text{mL}$, categorized by ranges such as P50 ($5\text{--}50\,\mu\text{L}$), P200 ($20\text{--}200\,\mu\text{L}$), and P1000 ($100\text{--}1000\,\mu\text{L}$).

ELISA

Enzyme-Linked Immunosorbent Assay; a method used to measure the amount of antigen or protein in a sample using primary antibodies, enzyme-linked (HRP) secondary antibodies, and substrate.

Bradford Lab Assay

A procedure used to measure protein quantity in a solution using Coomassie Blue dye and a spectrophotometer.

Coomassie Blue Dye

The Bradford reagent that absorbs light at $595\,\text{nm}$ (blue) when bound to protein and at $470\,\text{nm}$ (reddish/brown) when no protein is bound.

Beer's Law

The physical law represented by $A = \varepsilon b c$, relating absorbance ($A$) to molar absorptivity ($\varepsilon$), path length ($b$), and protein concentration ($c$ in $\text{mg/mL}$).

Gel Electrophoresis

A technique used to separate negatively charged DNA toward the positive electrode according to size, where smaller fragments travel farther.

SYBR

A fluorescent dye used to stain DNA so it appears bright green and can be visualized under UV or bright blue light.

DNA Ladder

A standard reference sample consisting of known DNA fragment sizes used to determine the size of experimental DNA bands.

Alu Element

A repetitive DNA sequence approximately $300\,\text{bp}$ long located in non-coding regions (introns).

Dimorphic Alu

An Alu insertion that is not present at a particular chromosomal location in all individuals.

PV92

A dimorphic Alu insertion locus located on human chromosome $16$.

Polymorphisms

Differences in DNA sequence between individual organisms.

Centrifugation

A laboratory method that separates materials based on density and forms cell pellets at the bottom of the tube.

Lysis Buffer

A chemical buffer that helps break open cells to release DNA into solution.

$55^\circ\text{C}$ Incubation

A temperature incubation step that protects DNA from degradation by inactivating DNase.

$100^\circ\text{C}$ Incubation

A boiling incubation step that ruptures the cell membrane, denatures proteins, and loosens connectivity.

Polymerase Chain Reaction (PCR)

A molecular technique used to amplify or make copies of target DNA.

Denaturation

The first step of PCR where double-stranded DNA separates into single strands by breaking hydrogen bonds at high temperature ($94^\circ\text{C}$).

Annealing

The second step of PCR where specific primers bind to the complementary regions on the target DNA.

Extension

The third step of PCR where Taq polymerase synthesizes new DNA by adding nucleotides at $72^\circ\text{C}$.