Biology 1A03 test 2 Questions Answered Correctly Latest Version 2025-2026
How many protein encoding genes - Answers 20-25k
How many proteins in our body approximately - Answers 1M
What does that mean? - Answers Each protein encodding gene codes for many proteins
How is the complex proteome possible? - Answers Alternative splicing and post translational
modifications
How does compartmentalization help eukaryotes? - Answers Mature mRNA leaves nucleus to
cytosol where free. bound or ER bound ribsomes facilate translation into polypeptide
What is a stimulus - Answers A change in the environment for example increased glucose
What specalized cell is responsible for bringing glucose levels to normal and where is it found? -
Answers Beta Islet cells in Pancreas
What does Beta Islet cells produce and what are they called - Answers They produced Insulin
and they are effector proteins
Role of Insulin as an effector protein - Answers Produces response on glucose levels
Where does early glucose digestion occurs - Answers In the epithelial surfaces of the mouth
Where does majority of the glucose digestion occur - Answers In the microvilli in the small
intestine
What is the microvilli - Answers Small blood vessels that absorb glucose and carry it through
the circulatory system.
How is the biosynthesis of Insulin regulated - Answers Regulated by trasncription and
translation. The insulin gene detects increase in the need of glucose metabolisation. and
increase insulin gene and increase mRNA.
Where is insulin produced - Answers In the dense ER network in the beta islet cells
How many amino acids is the translated polypeptide from insulin gene - Answers 110AA
How many amino acids is translated polypeptide from functional insulin gene - Answers 51AA
What did Dorothy Hodkin do? - Answers She did X-Ray crystallography, found insulin is made of
two chains Alpha chain - 21 AA and Beta Chain - 30 AA
What do the alpha and beta chain form when they fold - Answers Dimer
What is the insulin gene called when it has 110 AA - Answers Preproinsulin
,How is preproinsulin converted to proinsulin - Answers Preproinsulin contains an N-terminal
which binds to an SRP which then facilates translocation of preproinsulin into the ER where the
signal sequence then unbinds
How is proinsulin converted to insulin - Answers Addition of three disulfide bonds C chain
removed and requires protein folding by chaperone proteins in ER
What happens after folding of the protein: - Answers Transported to GA, cleavage occurs, forms
dimer with 51AA
Why are these modifcations important - Answers N-terminal and C-Terminal AA residue from A
and B chain can bind to insulin receptors
What are 3 types of Post translation modifcations that occur to the Insulin - Answers 1)
Cleavage
2) Di-Sulfide Bridge Formation
3) Covalent attachment of other molecules
3 types of covalent attachment - Answers 1) Phosphorylation : reversible, add P group to
threonine, serine or tyrosine.
2) Methylation - addition of methyl group
3). Acetylation - addition of acetyl group
Receptor Protein - Answers Interpretate info from singlalling proteins such as Insulin
What are receptor proteins? - Answers Monomers and have signals called ligands
What happens when ligands binds receptor protein - Answers The monomers, merge together
or dimerize which leads to a conformational change. Activated cystoplasmic domain
What does the cystoplasmic domain of receptor behave as - Answers Kinase proteins
What does the cystoplasmic domain of receptor do - Answers Phosphorylates each other at the
tails of the AA which binds and activates other cystoplamic proteins
What do these cytoplasmic proteins do - Answers They help activate intracellular signlas
through the use of diverse tranducer and activation proteins
Purpose of intracellular signals - Answers Aid glucose absorption
How are these signals regulated - Answers +ve feedback loops, -ve feedback loop or double
negative feedback loop
Different places glucose stored - Answers Fat adipocyte cells store glucose, fatty acids store
, glucose as triglycerides, liver and muscles take up glucoses, rest stored as glycogen.
What happens through alternative splicing - Answers More then one mRNA transcript produces
from a single gene, adds to our diverse proteome
Isoform - Answers Pre-mRNA has its exons removed due to identification as introns. This leads
to many isoforms of the same mRNA
Purpose of isoforms - Answers Helps regulate gene expression with similar genes
Example of isoforms in skeletal and liver cells - Answers Skeletal muscles do not have exon 11
in their primary trasncript of 22 exons, whilst liver cells do. This gives skeletal cells a higher
affinity for insulin as obviously it will require more glucose becuse more ATP.
Negative feedback loop - Answers Decrease in glucose levels detected, decrease in insulin
What would happen if there was a change in post translational modification for insulin -
Answers Insulin protein would not bind receptors, glucose transport proteins would not be
activated, there would be no aid in glucose absorbtions, leads to hyperglycemia and diabetes.
Tetracycline - Answers Antibiotic used with those who have acne. It inteferes with the process
of translation, thus protein would not develop.
George Beadle and Edward Tatum - Answers They said if radiation is exposed to genes it would
destroy it and said that each gene codes for one enzyme
Wildtype Characterstics - Answers Organisms that grow on minimal medium
minimal medium - Answers medium containing only inorganic salts, a carbon source, and water
Srb and Horowitz hypothesis - Answers Precursor > Orithinine > Citruline > Arginine. Each gene
responsible for creating the enzyme that codes for the next precursor. They created three
mutants, arg 1, 2 and 3 that creates defects in the enzymes and thus the only way to grow was
to add subsequent precursor supplements that the enzyme could not grow.
Why did one gene one enzyme turn into one gene one polypeptide - Answers Almost all
enzymes code for proteins but not all proteins are enzymes
What is the one gene, one... hypothesis - Answers Vast array of post translational modifcations
diversify the protein
How do Mytilus Marine Mussels cling to rocks - Answers They produce a strong adhesive from
their muscular feet. These are fibers and are proteins
What is the protein called - Answers Adhesive called Byssus
What does adhesive contain - Answers Keratin and resinous proteins
How many protein encoding genes - Answers 20-25k
How many proteins in our body approximately - Answers 1M
What does that mean? - Answers Each protein encodding gene codes for many proteins
How is the complex proteome possible? - Answers Alternative splicing and post translational
modifications
How does compartmentalization help eukaryotes? - Answers Mature mRNA leaves nucleus to
cytosol where free. bound or ER bound ribsomes facilate translation into polypeptide
What is a stimulus - Answers A change in the environment for example increased glucose
What specalized cell is responsible for bringing glucose levels to normal and where is it found? -
Answers Beta Islet cells in Pancreas
What does Beta Islet cells produce and what are they called - Answers They produced Insulin
and they are effector proteins
Role of Insulin as an effector protein - Answers Produces response on glucose levels
Where does early glucose digestion occurs - Answers In the epithelial surfaces of the mouth
Where does majority of the glucose digestion occur - Answers In the microvilli in the small
intestine
What is the microvilli - Answers Small blood vessels that absorb glucose and carry it through
the circulatory system.
How is the biosynthesis of Insulin regulated - Answers Regulated by trasncription and
translation. The insulin gene detects increase in the need of glucose metabolisation. and
increase insulin gene and increase mRNA.
Where is insulin produced - Answers In the dense ER network in the beta islet cells
How many amino acids is the translated polypeptide from insulin gene - Answers 110AA
How many amino acids is translated polypeptide from functional insulin gene - Answers 51AA
What did Dorothy Hodkin do? - Answers She did X-Ray crystallography, found insulin is made of
two chains Alpha chain - 21 AA and Beta Chain - 30 AA
What do the alpha and beta chain form when they fold - Answers Dimer
What is the insulin gene called when it has 110 AA - Answers Preproinsulin
,How is preproinsulin converted to proinsulin - Answers Preproinsulin contains an N-terminal
which binds to an SRP which then facilates translocation of preproinsulin into the ER where the
signal sequence then unbinds
How is proinsulin converted to insulin - Answers Addition of three disulfide bonds C chain
removed and requires protein folding by chaperone proteins in ER
What happens after folding of the protein: - Answers Transported to GA, cleavage occurs, forms
dimer with 51AA
Why are these modifcations important - Answers N-terminal and C-Terminal AA residue from A
and B chain can bind to insulin receptors
What are 3 types of Post translation modifcations that occur to the Insulin - Answers 1)
Cleavage
2) Di-Sulfide Bridge Formation
3) Covalent attachment of other molecules
3 types of covalent attachment - Answers 1) Phosphorylation : reversible, add P group to
threonine, serine or tyrosine.
2) Methylation - addition of methyl group
3). Acetylation - addition of acetyl group
Receptor Protein - Answers Interpretate info from singlalling proteins such as Insulin
What are receptor proteins? - Answers Monomers and have signals called ligands
What happens when ligands binds receptor protein - Answers The monomers, merge together
or dimerize which leads to a conformational change. Activated cystoplasmic domain
What does the cystoplasmic domain of receptor behave as - Answers Kinase proteins
What does the cystoplasmic domain of receptor do - Answers Phosphorylates each other at the
tails of the AA which binds and activates other cystoplamic proteins
What do these cytoplasmic proteins do - Answers They help activate intracellular signlas
through the use of diverse tranducer and activation proteins
Purpose of intracellular signals - Answers Aid glucose absorption
How are these signals regulated - Answers +ve feedback loops, -ve feedback loop or double
negative feedback loop
Different places glucose stored - Answers Fat adipocyte cells store glucose, fatty acids store
, glucose as triglycerides, liver and muscles take up glucoses, rest stored as glycogen.
What happens through alternative splicing - Answers More then one mRNA transcript produces
from a single gene, adds to our diverse proteome
Isoform - Answers Pre-mRNA has its exons removed due to identification as introns. This leads
to many isoforms of the same mRNA
Purpose of isoforms - Answers Helps regulate gene expression with similar genes
Example of isoforms in skeletal and liver cells - Answers Skeletal muscles do not have exon 11
in their primary trasncript of 22 exons, whilst liver cells do. This gives skeletal cells a higher
affinity for insulin as obviously it will require more glucose becuse more ATP.
Negative feedback loop - Answers Decrease in glucose levels detected, decrease in insulin
What would happen if there was a change in post translational modification for insulin -
Answers Insulin protein would not bind receptors, glucose transport proteins would not be
activated, there would be no aid in glucose absorbtions, leads to hyperglycemia and diabetes.
Tetracycline - Answers Antibiotic used with those who have acne. It inteferes with the process
of translation, thus protein would not develop.
George Beadle and Edward Tatum - Answers They said if radiation is exposed to genes it would
destroy it and said that each gene codes for one enzyme
Wildtype Characterstics - Answers Organisms that grow on minimal medium
minimal medium - Answers medium containing only inorganic salts, a carbon source, and water
Srb and Horowitz hypothesis - Answers Precursor > Orithinine > Citruline > Arginine. Each gene
responsible for creating the enzyme that codes for the next precursor. They created three
mutants, arg 1, 2 and 3 that creates defects in the enzymes and thus the only way to grow was
to add subsequent precursor supplements that the enzyme could not grow.
Why did one gene one enzyme turn into one gene one polypeptide - Answers Almost all
enzymes code for proteins but not all proteins are enzymes
What is the one gene, one... hypothesis - Answers Vast array of post translational modifcations
diversify the protein
How do Mytilus Marine Mussels cling to rocks - Answers They produce a strong adhesive from
their muscular feet. These are fibers and are proteins
What is the protein called - Answers Adhesive called Byssus
What does adhesive contain - Answers Keratin and resinous proteins
