BI 234 exam QUESTION TEST WITH
ACCURATE ANSWERS NEW VERSION
LATEST UPDATE2024-2025.
Explain how the product in a metabolic pathway may control its own synthesis.
- Ans - when enough product has been produced, it may bind to the inhibitor and induce
a halt to synthesis of that pathway.
beta-galactosidase
- Ans - an enzyme that catalyzes the conversion of lactose into monosaccharides
Amylase –
Ans - Enzyme in saliva that breaks the chemical bonds in starches
Catalase
- Ans - An enzyme produced in all cells to decompose hydrogen peroxide, a by-product
of cell respiration
Lipase - Ans - pancreatic enzyme necessary to digest fats into fatty acids
constitutive genes
- Ans - genes that are expressed all the time
repressible genes - Ans - genes are on and can be turned off
inducible genes
- Ans - Genes whose expression is turned on by the presence of some substance.
Regulate catabolic pathways.
repressible enzymes - Ans - function in anabolic pathways; their synthesis is repressed
by high levels of the end product
inducible enzymes
- Ans - An enzyme whose transcription can be stimulated by an abundance of its
substrate (as opposed to repressible enzyme). Usually in catabolism.
constitutive enzymes
- Ans - always present, always produced in equal amounts or at equal rates, regardless
of the amount of substrate
disulfide bridges - Ans - covalent bonds that may further reinforce the shape of a
protein.
strong bonds that have a higher denaturation temperature, so are commonly found in
hyperthermophiles.
,catalase producing bacteria
- Ans - use oxygen
beta galactosidase producing bacteria - Ans - use lactose
amylase producing bacteria
- Ans - digest carbohydrates
lipase producing bacteria - Ans - digest lipids
Exotoxins
- Ans - toxic substances that bacteria secrete into their environment
ex. Clostridium
Gene - Ans - A segment of DNA on a chromosome that codes for a specific trait
Genotype vs. Phenotype
- Ans - An organism's genotype is the set of genes that it carries. An organism's
phenotype is all of its observable characteristics
gene expression - Ans - process by which a gene produces its product and the product
carries out its function
Promotor
- Ans - A region of DNA with a specific sequence that tells RNA polymerase where to
begin transcription.
operator - Ans - Region of DNA that controls RNA polymerase's access to a set of
genes with related functions.
inducible operon
- Ans - structural genes are not transcribed unless an inducer is present
repressible operon - Ans - Usually on; binding of a repressor to the operator shuts off
transcription
metabolic pathway
- Ans - Begins with a specific molecule, which is then altered in a series of defined
steps, resulting in a certain product.
Pathogenicity - Ans - ability to cause disease
Biofilm - Ans - A surface-coating colony of one or more species of prokaryotes that
engage in metabolic cooperation.
, quorum sensing
- Ans - The ability of bacteria to sense the presence of other bacteria via secreted
chemical signals.
Streptococcus mutans - Ans - causes dental caries by attaching to the tooth and
creating plaque (biofilm) that eats at the enamel of the tooth
Snyder Agar test
- Ans - Tests for susceptibility to dental caries. Yellow= high, blue/green= low
- Ans -
Autotroph - Ans - An organism that makes its own food
Heterotroph
- Ans - organism that obtains energy from the foods it consumes; also called a
consumer
Eukaryote - Ans - A cell that contains a nucleus and membrane bound organelles
Prokaryote
- Ans - A unicellular organism that lacks a nucleus and membrane bound organelles
Major characteristics of bacteria and archaea - Ans - -unicellular
-prokaryotes
-may have flagella
-binary fission
-cell wall
-heterotrophs and autotrophs
Archaea have psuedomurein cell wall; bacteria have peptidoglycan cell wall.
Major characteristics of Fungi
- Ans - - heterotrophs
- unicellular or multicellular
- eukaryotes
- non-motile
- mitosis (budding)
- cell wall made of chitin
Major characteristics of Protozoa
- Ans - - autotrophs and heterotrophs
- unicellular
- eukaryotes
- flagella, cilia, pseudopods, or non-motile
ACCURATE ANSWERS NEW VERSION
LATEST UPDATE2024-2025.
Explain how the product in a metabolic pathway may control its own synthesis.
- Ans - when enough product has been produced, it may bind to the inhibitor and induce
a halt to synthesis of that pathway.
beta-galactosidase
- Ans - an enzyme that catalyzes the conversion of lactose into monosaccharides
Amylase –
Ans - Enzyme in saliva that breaks the chemical bonds in starches
Catalase
- Ans - An enzyme produced in all cells to decompose hydrogen peroxide, a by-product
of cell respiration
Lipase - Ans - pancreatic enzyme necessary to digest fats into fatty acids
constitutive genes
- Ans - genes that are expressed all the time
repressible genes - Ans - genes are on and can be turned off
inducible genes
- Ans - Genes whose expression is turned on by the presence of some substance.
Regulate catabolic pathways.
repressible enzymes - Ans - function in anabolic pathways; their synthesis is repressed
by high levels of the end product
inducible enzymes
- Ans - An enzyme whose transcription can be stimulated by an abundance of its
substrate (as opposed to repressible enzyme). Usually in catabolism.
constitutive enzymes
- Ans - always present, always produced in equal amounts or at equal rates, regardless
of the amount of substrate
disulfide bridges - Ans - covalent bonds that may further reinforce the shape of a
protein.
strong bonds that have a higher denaturation temperature, so are commonly found in
hyperthermophiles.
,catalase producing bacteria
- Ans - use oxygen
beta galactosidase producing bacteria - Ans - use lactose
amylase producing bacteria
- Ans - digest carbohydrates
lipase producing bacteria - Ans - digest lipids
Exotoxins
- Ans - toxic substances that bacteria secrete into their environment
ex. Clostridium
Gene - Ans - A segment of DNA on a chromosome that codes for a specific trait
Genotype vs. Phenotype
- Ans - An organism's genotype is the set of genes that it carries. An organism's
phenotype is all of its observable characteristics
gene expression - Ans - process by which a gene produces its product and the product
carries out its function
Promotor
- Ans - A region of DNA with a specific sequence that tells RNA polymerase where to
begin transcription.
operator - Ans - Region of DNA that controls RNA polymerase's access to a set of
genes with related functions.
inducible operon
- Ans - structural genes are not transcribed unless an inducer is present
repressible operon - Ans - Usually on; binding of a repressor to the operator shuts off
transcription
metabolic pathway
- Ans - Begins with a specific molecule, which is then altered in a series of defined
steps, resulting in a certain product.
Pathogenicity - Ans - ability to cause disease
Biofilm - Ans - A surface-coating colony of one or more species of prokaryotes that
engage in metabolic cooperation.
, quorum sensing
- Ans - The ability of bacteria to sense the presence of other bacteria via secreted
chemical signals.
Streptococcus mutans - Ans - causes dental caries by attaching to the tooth and
creating plaque (biofilm) that eats at the enamel of the tooth
Snyder Agar test
- Ans - Tests for susceptibility to dental caries. Yellow= high, blue/green= low
- Ans -
Autotroph - Ans - An organism that makes its own food
Heterotroph
- Ans - organism that obtains energy from the foods it consumes; also called a
consumer
Eukaryote - Ans - A cell that contains a nucleus and membrane bound organelles
Prokaryote
- Ans - A unicellular organism that lacks a nucleus and membrane bound organelles
Major characteristics of bacteria and archaea - Ans - -unicellular
-prokaryotes
-may have flagella
-binary fission
-cell wall
-heterotrophs and autotrophs
Archaea have psuedomurein cell wall; bacteria have peptidoglycan cell wall.
Major characteristics of Fungi
- Ans - - heterotrophs
- unicellular or multicellular
- eukaryotes
- non-motile
- mitosis (budding)
- cell wall made of chitin
Major characteristics of Protozoa
- Ans - - autotrophs and heterotrophs
- unicellular
- eukaryotes
- flagella, cilia, pseudopods, or non-motile
