BIS 2A Midterm 2 Test Questions with
Complete Solutions.
What are proteins made of? - Answer Proteins are made up of amino acids linked together
by peptide bonds, as well as the R groups attached to the amino acids (which make them
unique and give certain characteristics)
Proteins are formed through the process of condensation, when the carboxylic group and the
amine group of the amino acids bind together to produce water, forming a peptide bond.
How the various levels of organization (primary, secondary...) affect the structure and activity of
an enzyme? - Answer -3D structure and pattern of charges/hydrophobic patches allow
enzyme to bind to correct substrates
How the concentration of a catalyst influences the rate of a reaction. Under what circumstances
is the rate is limited by the [catalyst] vs. [substrate]? - Answer -When there is a high
concentration of substrate, the rate of reaction is limited by the catalyst.
-When there is a low concentration of substrate, the rate of reaction is limited by how many
times the substrate and enzyme/catalyst bump into each other.
Primary structure, secondary structure, tertiary structure, and quaternary structure - Answer
Primary: the chain of amino acids connected by peptide bonds
Secondary: Stabilized by hydrogen bonds, consist of alpha helix and beta pleated sheets.
Sequence can be predicted by R groups
Tertiary: Determined by R groups, very hard to predict. Stabilized by a bunch of weak reactions
between R groups and amino acids (ionic bonds)
Quaternary: also stabilized by a bunch of weak ionic reactions between R groups and amino
acids.
How do biological catalysts (proteins) make catalytic binding surfaces? - Answer Catalytic
binding surfaces are determined by R groups aka the pattern of charges/hydrophobic patches
on the 3D structure of the protein.
How is reaction rate controlled by catalysts? - Answer Catalysts control reaction rate by
providing an alternate, faster route through the reaction. When there is a high concentration of
substrate, the rate is limited by the enzymes.
How changes in shape at one part of a protein can affect activities in another part - Answer
Allosteric inhibition:
-Inhibitor binds to allosteric site, shape of active site changes and substrate can no longer bind
, -Inhibitor can also bind to allosteric site close to active site and block substrate
-If substrate cannot bind then enzyme is not activated
Why is the "first dedicated step" is a smart place to regulate a long metabolic pathway - Answer
You don't want to inhibit the production of the original amino acid; you just want to regulate
the production of the product.
**Why biologists interested in Origins find methanogens particularly fascinating - Answer
Methanogens can be heterotrophs or autotrophs
Arguments and evidence against a heterotroph as the first possible life form - Answer
Heterotrophs use oxidative phosphorylation to produce their energy, so the environment would
have had to be O2 heavy. This was not the case, so heterotrophs were probably NOT the first life
form.
Why increasing cell size creates a crisis in the relationship between the cell and its environment
- Answer Surface area to volume ratio gets smaller as the diameter of cells increase. This is
not good because there is not enough membrane space for the metabolic activities that the cell
needs to do, in relation to the size.
-Reason why big cells are long and thin
Why cell walls can be handy - Answer Cell walls maintain the shape of the cell, resist osmotic
pressure.
What's the difference between proks and euks? - Answer Euks have organelles and proks
don't; also, eukaryotes are usually larger than prokaryotes
Why are archeans considered a new "domain" of life, and why did it take so long to discover
them? - Answer Distantly related to bacteria, it was hard to discover these "extremophiles"
due to the environments that they thrived in.
How are the three domains related to each other? - Answer Archaea and Eukaryotes share 3
RNA polymerases, histones, and introns in genes
-More closely related than bacteria
Bacteria and Archaea are both simple cells, but bacteria differs from archaea and eukaryotes bc
they have 1 RNA polymerase, no histones, and no introns in genes
"fermenting predator" vs. the "hydrogen hypothesis" models for the origins of eukaryotes? -
Answer Fermenting Predator:
Complete Solutions.
What are proteins made of? - Answer Proteins are made up of amino acids linked together
by peptide bonds, as well as the R groups attached to the amino acids (which make them
unique and give certain characteristics)
Proteins are formed through the process of condensation, when the carboxylic group and the
amine group of the amino acids bind together to produce water, forming a peptide bond.
How the various levels of organization (primary, secondary...) affect the structure and activity of
an enzyme? - Answer -3D structure and pattern of charges/hydrophobic patches allow
enzyme to bind to correct substrates
How the concentration of a catalyst influences the rate of a reaction. Under what circumstances
is the rate is limited by the [catalyst] vs. [substrate]? - Answer -When there is a high
concentration of substrate, the rate of reaction is limited by the catalyst.
-When there is a low concentration of substrate, the rate of reaction is limited by how many
times the substrate and enzyme/catalyst bump into each other.
Primary structure, secondary structure, tertiary structure, and quaternary structure - Answer
Primary: the chain of amino acids connected by peptide bonds
Secondary: Stabilized by hydrogen bonds, consist of alpha helix and beta pleated sheets.
Sequence can be predicted by R groups
Tertiary: Determined by R groups, very hard to predict. Stabilized by a bunch of weak reactions
between R groups and amino acids (ionic bonds)
Quaternary: also stabilized by a bunch of weak ionic reactions between R groups and amino
acids.
How do biological catalysts (proteins) make catalytic binding surfaces? - Answer Catalytic
binding surfaces are determined by R groups aka the pattern of charges/hydrophobic patches
on the 3D structure of the protein.
How is reaction rate controlled by catalysts? - Answer Catalysts control reaction rate by
providing an alternate, faster route through the reaction. When there is a high concentration of
substrate, the rate is limited by the enzymes.
How changes in shape at one part of a protein can affect activities in another part - Answer
Allosteric inhibition:
-Inhibitor binds to allosteric site, shape of active site changes and substrate can no longer bind
, -Inhibitor can also bind to allosteric site close to active site and block substrate
-If substrate cannot bind then enzyme is not activated
Why is the "first dedicated step" is a smart place to regulate a long metabolic pathway - Answer
You don't want to inhibit the production of the original amino acid; you just want to regulate
the production of the product.
**Why biologists interested in Origins find methanogens particularly fascinating - Answer
Methanogens can be heterotrophs or autotrophs
Arguments and evidence against a heterotroph as the first possible life form - Answer
Heterotrophs use oxidative phosphorylation to produce their energy, so the environment would
have had to be O2 heavy. This was not the case, so heterotrophs were probably NOT the first life
form.
Why increasing cell size creates a crisis in the relationship between the cell and its environment
- Answer Surface area to volume ratio gets smaller as the diameter of cells increase. This is
not good because there is not enough membrane space for the metabolic activities that the cell
needs to do, in relation to the size.
-Reason why big cells are long and thin
Why cell walls can be handy - Answer Cell walls maintain the shape of the cell, resist osmotic
pressure.
What's the difference between proks and euks? - Answer Euks have organelles and proks
don't; also, eukaryotes are usually larger than prokaryotes
Why are archeans considered a new "domain" of life, and why did it take so long to discover
them? - Answer Distantly related to bacteria, it was hard to discover these "extremophiles"
due to the environments that they thrived in.
How are the three domains related to each other? - Answer Archaea and Eukaryotes share 3
RNA polymerases, histones, and introns in genes
-More closely related than bacteria
Bacteria and Archaea are both simple cells, but bacteria differs from archaea and eukaryotes bc
they have 1 RNA polymerase, no histones, and no introns in genes
"fermenting predator" vs. the "hydrogen hypothesis" models for the origins of eukaryotes? -
Answer Fermenting Predator:
