Exam Questions and Answers 2024
In a covalent bond, the bond can be either polar or... - (answers)Nonpolar.
Polarity deals with the _______ of electrons. - (answers)Sharing
Each atom can have a slight _______. These dictate how each atom will share
________. - (answers)Charge
Electrson
Nonpolar bonds means there is __________ sharing of electrons. Polar bonds
have ____________ sharing. - (answers)Equal
Nonequal
Endocytosis - (answers)What many single-celled eukaryotes use to ingest food
particles.
The plasma membrane surrounds/engulfs the food particle.
There are three types of endocytosis: phagocytosis, pinocytosis, and receptor
mediated endocytosis.
Phagocytosis - (answers)Used when the material being taken in is "particulate",
like a bacterial cell or an organic fragment
Pinocytosis - (answers)Used when the material being taken in is liquid
Receptor Mediated Endocytosis - (answers)Used when the material being taken
in needs to be transported across the plasma membrane via receptors. The
,molecules will bind to a specific site embedded in the plasma membrane. These
receptor molecules are in a concentrated location coated by the protein clathrin.
When enough material molecules accumulate, the pit deepens and seals up to be
incorporated into the cell as a vesicle.
Exocytosis - (answers)Opposite of endocytosis.
The process results in the discharge of materials from membrane-bound
packages that migrate to the inner surface of the plasma membrane, fuse with
the membrane and then release the contents outside of the cell.
Protein Denaturation - (answers)Changes the solubility of individual protein
molecules, entrapping solvent water into a semisolid gel structure
What is Jell-O a good example of? - (answers)The process of coagulation of
proteins into a 3D latticework that entraps water molecules to produce a
semisolid gel
How are proteins synthesized? - (answers)By polymerizing amino acids.
This occurs by repeatedly forming peptide bonds that link individual amino
acids together into a chain.
What three features influence the 3D shape of a water soluble protein? -
(answers)Primary structure
Secondary structure
Tertiary structure
Primary Structure - (answers)The peptide bond between individual amino acids
that creates a long chain of connected amino acids
These include hydrophilic and hydrophobic projections (that are oriented
perpendicular to the chain)
,Secondary Structure - (answers)The helix that the protein chain curls into as a
result of hydrogen bonds and other weak forces
Tertiary Structure - (answers)Created when the protein molecules fold back on
themselves outside of the helical segments
Putting the hydrophobic portions on the inside and the hydrophilic portions on
the outside
Denaturation - (answers)When natural proteins are subjected to
physical/chemical treatment and their structures change
They become "un-native or "unnatural"
What does heating proteins do to them? - (answers)Imparts energy to the
molecules
This added energy breaks the relatively weak forces that hold the protein
together (in tertiary and secondary structures)
As the heat continues, the protein molecule unfold more and more
The hydrophilic regions are now exposed to the outside of the molecule
Are peptide bonds hydrophilic or phobic? - (answers)Hydrophilic
What happens when protein molecules are denatured and unwound? -
(answers)They attract water molecules
This traps the water molecules in close proximity to the protein strands
What happens when hydrophobic molecules are exposed? - (answers)They
become unstable in aqueous environments
They will then associate with other hydrophobic molecules on other protein
molecules
, What is the end result of heating proteins? - (answers)Water molecules adhere
to the surface of hydrophilic regions and hydrophobic regions dissolve into each
other to provide the energy to retain the structure of the protein
It becomes a large insoluble mass with randomly organized structural
framework
What is frying an egg an example of? - (answers)Irreversibly denatured proteins
resulting in the formation of a solid gel
The gel entraps water molecules into a semi solid structure
How does the negative feedback go for thirst? - (answers)-Situation: during a
hot day, water is lost through sweat and produces a condition of decreasing
blood/fluid volume
-Response: blood (fluid) volume decreases, can also be stated as increasing the
osmolarity (or concentration of solutes) of blood
-Detection: increasing osmolarity of the blood is detected by the osmoreceptors
in the hypothalamus
-Trend: the sense of thirst is enhance partially as a result of antidiuretic hormone
-Effect: drinking of fluids reverses the declining water volume
What are enzymes? - (answers)Proteins that speed up chemical reactions in the
cell
What is the active site on an enzyme for? - (answers)Meant to be a specific
shape to bind to substrate molecules
How does an enzyme work? - (answers)By binding to one+ specific molecules
or substrates (this occurs at the active site)
This creates an enzyme-substrate complex