QUIZ 2 Flashcards
Which of the following statements about signaling substances is wrong?
A. Signaling molecules secreted by neurons to signal to other neurons are called neurotransmitters
B. In a broader sense all signaling molecules arriving from extracellular space can be considered hormone
C. Signaling molecules secreted by neurons into the circulation to regulate the behavior of other non-neuronal cells is called a neurocrine hormone
D. Substances that are secreted by one type of cells into circulation and act upon other cell types are called hormones
E. Some nutrients/metabolites can function as hormones
C. Signaling molecules secreted by neurons into the circulation to regulate the behavior of other non-neuronal cells is called a neurocrine hormone
Which of the following features of endocrine system allows for organisms to maintain homeostasis?
A. Complex communication network through multiple hormones
B. General high concentrations of hormones in circulation
C. Complex communication networks with redundant functions
D. Complex communication networks with precise positive and negative interactions
E. High specificity between hormones and their receptors
C. Complex communication networks with redundant functions
Which of the following statements about endocrine glands is false?
A. They secrete one or more hormones into circulation and thus regulate function of other organs
B. Unlike exocrine glands, they do not have ducts for secretion of hormones
C. Peptide hormones are stored, while lipid hormones are not.
D. Ovarian corpus luteum is not a gland as it is not a permanent structure in the ovary
E. All the statements above are correct
D. Ovarian corpus luteum is not a gland as it is not a permanent structure in the ovary
Which of the following statements about hormone receptors is false?
A. Protein hormones being water soluble have receptors in the cell membrane
B. Hormone receptors are single or multiple proteins in complex
C. Eicosanoids being fat soluble have intra-cellular receptors
D. Intracellular receptors typically elicit slower response as they mainly regulate transcription
E. All the statements above are correct
C. Eicosanoids being fat soluble have intra-cellular receptors
Which of the following hormones is (are) transported in the circulation as bound to “hormone binding proteins”?
A. Estradiol
B. Thyroid hormone
C. Insulin-like growth factor 1 (IGF-1)
D. Only A and B, as they are hydrophobic hormones
E. All three hormones are transported with binding proteins
E. All three hormones are transported with binding proteins
Which of the following hormones is (are) stored in secretory granules in the cells where they are synthesized?
A. Progesterone
B. Follicle stimulating hormone (FSH)
C. Insulin
D. Testosterone
E. Only B and C are stored in secretory granules
E. Only B and C are stored in secretory granules
Which of the following statements concerning signal transduction by the insulin receptor is not correct?
A. Activation of the receptor protein kinase activity results in the activation of additional protein kinases.
B. The substrates of the receptor protein kinase activity are mainly proteins that regulate transcription.
C. Binding of insulin to the receptor activates a protein kinase.
D. Binding of insulin to the receptor results in a change in its quaternary structure.
E. The receptor protein kinase activity is specific for tyrosine residues on the substrate proteins.
B. The substrates of the receptor protein kinase activity are mainly proteins that regulate transcription.
Which of the following kinases plays an important role in epinephrin signaling?
A. PKA
B. PKB
C. PKC
D. Both A and C
E. All kinases listed above
D. Both A and C
Which of the following kinases plays an important role in growth hormone signaling?
A. PKA
B. PKB
C. PKC
D. Both A and C
E. All kinases listed above
B. PKB
Which of the following statements about G-protein coupled receptor (GPCR) signaling is correct?
A. Second messenger AMP is important for this signaling pathway
B. G-alpha protein disassociates from the receptor to activate its substrates
C. Nucleic phosphodiesterase is important to activate GPCR signaling
D. PI3-kinase plays a role in GPCR signaling through IP3 and Calcium
E. All the statements above are correct
B. G-alpha protein disassociates from the receptor to activate its substrates
Which of the following hormones is synthesized from proteins coded from two different genes?
A. Insulin
B. Luteinizing hormone (a gonadotropin)
C. Calcitonin
D. Adrenaline
E. Thyroid hormone
B. Luteinizing hormone (a gonadotropin)
Gluconeogenesis is_____
a) modification of glucose into protein
b) helpful to reduce blood glucose after sugar consumption
c) synthesis of glucose from a non-carbohydrate precursor
d) synthesis of glycogen from glucose
e) breakdown of glycogen into glucose
c) synthesis of glucose from a non-carbohydrate precursor
Which one of the following statements about eukaryotic gene regulation is not correct?
a) Access to promoters is restricted by the structure of chromatin.
b) Most regulation is negative involving repressors.
c) Larger and more multimeric proteins are involved in regulation of transcription.
d) Transcription and translation are separated in both space and time.
e) Alternative splicing of mRNA takes place as gene is being transcribed.
b) Most regulation is negative involving repressors.
Glycosis is _______
a) a pathway of glucose metabolism
b) a pathway of fatty acid metabolism
c) a pathway of protein metabolism
d) a pathway of nucleic acid metabolism
e) a pathway of steroid metabolism
A a) a pathway of glucose metabolism
Which of the following statements is false about human cells?
a) Human cells are eukaryotic
b) Cells do not have cell wall
c) Cells are organized to form tissues
d) Regulation of gene expression is complex due to involvement of promoters and enhancers
e) All human cells have nucleus
e) All human cells have nucleus
What is not true concerning ketone bodies?
a) They are metabolized to pyruvate for energy in tissues
b) They are produced by the liver, to be transported to other tissues as energy molecules
c) They are water soluble and thus easily transported through blood
d) Acetyl-CoA is the precursor for ketone body synthesis in the liver
e) The levels of ketone bodies in circulation increases during starvation
a) They are metabolized to pyruvate for energy in tissues
Which of the following tissues respond to insulin by up-taking glucose?
a) Muscle
b) Adipose tissue
c) Liver
d) Only the liver and muscle
e) Only muscle and adipose
e) Only muscle and adipose
Which of the following is not a hormone-producing organ?
a) Hypothalamus
b) Pituitary
c) Adrenal gland
d) Thyroid
e) Liver
e) Liver
Which of the following is not an intermediate of the citric acid cycle?
a) Acetyl-CoA
b) Citrate
c) Oxaloacetate
d) Succinyl-CoA
e) ⍺-Ketoglutarate
a) Acetyl-CoA
The ion channel that opens in response to acetylcholine is an example of a ____________ signal transduction system.
a) G-protein
b) ligand-gated
c) receptor-enzyme
d) nuclear receptor
e) voltage-gated
b) ligand-gated
Protein translation takes place in the_____
a) Nucleus
b) Cytoplasm
c) Cell membrane
d) Mitochondria
e) Extracellular space
b) Cytoplasm
In comparison with the resting state, actively contracting human muscle tissue has a _________
a) higher concentration of ATP
b) higher rate of lactate formation
c) lower consumption of glucose
d) lower rate of oxygen consumption
e) lower ratio of NADH to NAD+
b) higher rate of lactate formation
Triacylglycerols are composed of:
a) A glycerol backbone
b) Three fatty acids
c) Amide linkages between the fatty acids and glycerol
d) A and B above
e) A, B, and C above
e) A, B, and C above
Ketone bodies are produced from the metabolism of:
a) Fatty acids
b) Carbohydrates
c) Amino acids
d) Nucleic acids
e) Ketone bodies are not produced by mammals
a) Fatty acids
When a muscle is stimulated to contract aerobically, less lactic acid is formed than when it contracts anaerobically because:
a) Glycolysis does not occur to significant extent under aerobic conditions
b) Muscle is metabolically less active under aerobic than anaerobic conditions
c) The lactic acid generated is rapidly incorporated into lipids under aerobic conditions
d) Under aerobic conditions, the metabolic pathway is the pentose phosphate pathway that does not produce lactate
e) Under aerobic conditions, most of the pyruvate generated as a result of glycolysis is oxidized by the citric acid cycle rather than reduced to lactate
e) Under aerobic conditions, most of the pyruvate generated as a result of glycolysis is oxidized by the citric acid cycle rather than reduced to lactate
Which of the post-translational modifications is known to result in a reduction in protein concentration?
a) Addition of Phosphate group (phosphorylation)
b) Addition of Acetylation group (acetylation)
c) Addition of Methylation group (methylation)
d) Addition of Ubiquitin groups (ubiquitination)
e) Localization of protein to the mitochondria
d) Addition of Ubiquitin groups (ubiquitination)
Which one of the following is true about the genetic code?
a) All codons recognized by a given tRNA encode different amino acids
b) The codons are absolutely identical in coding for amino acids in all living organisms
c) Multiple codons may encode the same amino acid
d) The base in the middle position of the tRNA anticodon sometimes permits “wobble” base pairing with two or three different codons
e) The first position of the tRNA anticodon is always adenosine
c) Multiple codons may encode the same amino acid
Gene silencing by RNA interference acts by ________________ of the target gene.
a) inhibiting translation
b) degradation of the mRNA
c) inhibiting transcription
d) inhibiting alternative splicing
e) inhibiting poly-A tail formation
b) degradation of the mRNA
Alternative splicing of mRNA may result in:
a) a shift in the ratio of mRNA produced from two adjacent genes.
b) attachment of the poly(A) tail to the 5’ end of an mRNA.
c) inversion of certain exons in the final mRNA.
d) the production of the same protein from two different genes.
e) the production of two distinct proteins from a single gene.
e) the production of two distinct proteins from a single gene.
β-oxidation is _______
a) a pathway of glucose metabolism
b) a pathway of fatty acid metabolism
c) a pathway of protein metabolism
d) a pathway of nucleic acid metabolism
e) a pathway of steroid metabolism
b) a pathway of fatty acid metabolism
Glycogen is converted to monosaccharide units by:
a) Glucokinase
b) Glucose-6-phosphatase
c) Glycogen phosphorylase
d) Glycogen synthase
e) Glycogen’s
C c) Glycogen phosphorylase
The first reaction in glycolysis that results in the formation of an energy-rich compound is catalyzed by
a) glyceraldehyde 3-phosphate dehydrogenase
b) hexokinase
c) phosphoglycerate kinase
d) phosphofructokinase-1
e) None of these enzymes participate in glycolysis
a) glyceraldehyde 3-phosphate dehydrogenase
Energy required by the ATP synthase enzyme for its function comes from:
a) Chemical potential created by transfer of H+ ions out of mitochondria into cytoplasm
b) Electrochemical potential created across the inner mitochondrial membrane
c) Electrochemical potential created by transfer of H+ ions into mitochondrion
d) Electrical potential created by transfer of H+ ions from extracellular matrix into cytoplasm
e) ATP synthase does not require energy for its function
b) Electrochemical potential created across the inner mitochondrial membrane
Which of the following contains the highest percentage of triacylglycerols?
a) Chylomicrons
b) VLDL (very low-density lipoprotein)
c) LDL (low-density lipoprotein)
d) HDL (high-density lipoprotein)
e) None of the above contain triacylglycerols
A a) Chylomicrons
Which of the following is not a feature of signal transduction?
a) Integration of multiple pathways toward the same downstream response
b) Signal amplification
c) Covalent binding between the ligand and the receptor
d) Desensitization or adaptation of the receptor
e) Actually all the above are features of signal transduction
c) Covalent binding between the ligand and the receptor
Cell synthesizes ATP in ________
a) The mitochondria
b) The cytoplasm
c) The nucleus
d) Both mitochondria and cytoplasm
e) Both mitochondria and nucleus
d) Both mitochondria and cytoplasm
What are the 3 pillars for cellular communication ?
Proliferation (what type of cell to become)
differentiation
Homeostasis
What is the difference between nervous and hormonal (endocrine) communication ?
Hormonal is more direct, goes directly to any cell. however not be faster than nervous system communication
What is the first hormone discovered ?
secretin
Who discovered the first hormones ?
Ernest Starling (father and William Bayliss
What does hormone mean? (Etymology)
In greek: I excite, i arose, i set in motion
What does endocrine mean? (Etymology)
In greek and latin: internal secretion
