BIO test 1 study guide

Cellular signaling follows a cascade of events and has multiple points of regulation. Which of the following could be a reason(s) why a signalling cascade is interrupted, or turned 'off', once it has been turned 'on'?

(A) The ligand is prevented from reaching the binding site(B) A chemical modification occurred on serine, threonine, or tyrosine side chains to turn on/off proteins(C)a protein gets tagged with an ubiqutin group and gets degraded

Which of the following is an amino acid side chains can receives a terminal phosphate from an ATP molecule?

A. Serine B. Threonine C. Tyrosine

Which type of microscope requires two types of filters?

Fluorescent microscope

Which of the following does not take place in the mitochondria?

Glycolysis

What type of linkage links carbohydrates together?

Glycosidic

The immune system produces proteins called __________ that are __________ and attack __________.

antibodies; Y-shaped; antigens

Which signaling molecule is targetd by Viagra?

cGMP

Two organelles that likely evolved from an ancient symbiotic relationship between eukaryotes and bacteria are:

chloroplasts and mitochondria

A neurologist hears of a new drug for patients with neurological diseases such as Alzheimer's. To begin studying this drug, which model organism would the neurologist use and why?

elegan, because their neurons are completely mapped

Catalysts are molecules that lower the activation energy for a given reaction. Cells produce their own catalysts called _____________.

enzymes

In glycolysis, steps 6 and 7 are an example of coupled reactions. In step 6, the oxidation of a C-H bond in gyceraldeyde 3-phosphate is _______ and used to _________.

favorable, form NADH and a high-energy phosphate bond

In a folded protein, most of the nonpolar amino acids are buried inside the protein fold, whereas the polar and charged side chains are exposed to the components in the cytosol. This fold is more stable because of the expulsion of nonpolar atoms from contact with water, favoring the interaction of nonpolar atoms with each other. What is the term we use to refer to the nonpolar amino acids?

hydrophobic interaction

A DNA mutation occurs causing a change in the amino acid sequence of a protein in the area of the ligand binding site/active site. What will happen to ligand binding?

it depends on the properties of the new amino acid

True/False: Western blotting contains a small amount of bands that allows for better visualization and SDS-PAGE contains a lot of bands and is harder interpret

true

This type of microscopy uses a laser beam that focuses on a single plane to create Z-stacks that allow for a 3-D image.

Confocal microscope

This type of signaling has a membrane-bound signalling molecule that is created by one cell and is intended to reach another cell to cause an effect.

Contact dependent

Taxol is a common drug used in cancer treatments that acts as a microtubule stabilizer to inhibit cell division. If a researcher wanted to see how this drug affects development, which model organism would they use and why?

Danio rerio, because they are transparent their first two weeks of life

Mitochondria contain their own genome, are able to duplicate, and actually divide on a different timeline from the rest of the cell. Nevertheless, mitochondria cannot function for long when isolated from the cell because they are

Endosymbiotes

Acetyl Co Enzyme A can be derived from what sources?

Pyruvate and fatty acids

Which of the following factors determine an enzyme's specificity?

The three-demensional shape of the active site -An enzyme's specificity is determined by the 3D shape of its active site. Regardless of which theory of enzyme specificity we are discussing (lock and key or induced fit), the active site determines which substrate the enzyme will react with.

What unit of length would you generally use to measure a typical human cell?

micrometers

__________ are fairly small organelles that provide a safe place within the cell to carry out certain biochemical reactions that generate harmful, highly reactive oxygen species. These chemicals are both generated and broken down in the same location.

peroxisomes

Match the descriptions below with the types of microscopy. There is one best match for each.

phase-contrast: uses a light microscope with an optical component to take advantage of the different refractive indexes of light passing through different regions of the cell. bright-field: employs a light microscope and requires that samples be fixed and stained in order to reveal cellular details. fluorescence: requires the use of two sets of filters. The first filter narrows the wavelength range that reaches the specimen and the second blocks out all wavelengths that pass back up to the eyepiece except for those emitted by the dye in the sample. confocal: scans the specimen with a focused laser beam to obtain a series of two-dimensional optical sections, which can be used to reconstruct an image of the specimen in three-dimensions.The laser excites a fluorescent dye molecule, and the emitted light from each illuminated point is captured through a pinhole and recorded by a detector. transmission electron: has the ability to resolve cellular components a small as 2 nm. scanning electron: requires coating the sample with a thin layer of heavy metal to produce three-dimensional images of the surface of a sample.