bio Flashcards
A ribonucleoside has a ______ and a ________
hydroxyl group on the 2’ and 3’ carbons; purine
How many nitrogens are in an imidazole group?
2
Which of the following structures represents histidine with a protonated side chain?
Which of the following structures is a ribonucleoside?
The reaction in which histidine is converted to histamine is catalyzed by what enzyme?
histidine decarboxylase
What nitrogenous bases contain an imidazole group?
Adenine and Guanine
The alpha-helical structure of a protein is held together by what type of bond?
Hydrogen bonding between carbonyl oxygen and amino hydrogen atoms
Triacylglycerols consist of what?
Three fatty acid subunits connected to a three-carbon glycerol backbone
This molecule is classified as a:
deoxyribonucleotide
What enzyme unwinds the DNA helix and separates the strands?
helicase
What enzyme is responsible for reading the DNA template in a 3’ to 5’ direction and synthesizing the complementary strand in a 5’ to 3’ direction?
DNA polymerase
What enzyme synthesizes a short RNA primer that is used as the starting point for the synthesis of a new strand of DNA?
Primase
Increased molecular length and bulkiness would generate _____ ________
steric hindrance
complementary strands are always synthesized in _______ directions
opposite
What is the function of DNA polymerase α?
initiates synthesis in eukaryotes
What is the function of DNA polymerase δ?
synthesizes new DNA strands complementary to a template and requires an existing 3’ hydroxyl (OH) group to “build off of” as it extends its new strand
Examples of post-transcriptional modification include ________, ________, and ________
addition of a 5’ cap (specifically, a 7-methylguanylate cap), addition of a 3’ poly-A tail, and splicing
What is the start codon?
AUG
What are the three stop codons?
UGA, UAA, and UAG
What enzyme possesses a 3’-to-5’ exonuclease activity?
DNA polymerase
What is incomplete penetrance?
clinical symptoms (phenotype) are not always present in individuals who have the disease-causing mutation (genotype)
A test cross crosses the organism in question with an organism that is ________ for the ________ trait
homzygous; recessive
Diseases with high penetrance show what?
a high correlation between individuals that have the disease genotype and individuals who exhibit the signs and symptoms of the disease
Define the relationship between genetic linkage and the physical locations of two genes on the same chromosome
Genes that are physically far apart are less likely to be linked
What are the two equations for Hardy-Weinberg equilibrium?
- p² + 2pq + q² = 1 2. p+q = 1
p² and q² correspond to ________ individuals for p and q, respectively
homozygous
The 2pq term gives the frequency of _________
heterozygotes
__________ removes the positive charge on lysine residues in histone proteins, __________ the level of attraction between positively-charged histones & the negatively-charged DNA backbone. This creates [more or less] space between histones and DNA, making gene transcription easier
Acetylation; decreasing; more
The following structure depicts what?
cytosine
The following structure shows what?
addition of a methyl at C5
Transcription of structural lac genes takes place so the bacterium can metabolize the lactose sugar when lactose is [present or absent]
present
Allolactose binds to _______, causing it to dissociate from _______ region, freeing up the _______ region for transcription to take place
repressor; operator; operator
cDNA is reverse transcribed from the associated ____ molecule
mRNA
cDNA lacks ______
introns
cDNA is named for being ____________ to ____
complementary; mRNA
In an electrolytic cell, the anode is _______ & the cathode is _______
positive; negative
Sanger sequencing involves the use of _______________
dideoxynucleotides
What are dideoxynucleotides?
Nucleotides that lack an -OH group on both the 2’ and 3’ carbons
The highest-temperature step of a PCR reaction is the __________ step
denaturation
What is the denaturation step?
the step in which the reaction mixture is heated to around 95°C
Which cells make myelin in the CNS?
oligodendrocytes
Which cells make myelin in the PNS?
Schwann cells
What are the resident macrophages of the central nervous system called?
microglia
_____ are functional groups in which a carbonyl carbon is attached to another –OR group
Esters
Yes or No: Do N atoms have to be attached to at least 1 H atom to be an amine functional group?
No, amines can be attached to multiple R groups and no H atoms
Action potentials are what kind of phenomena?
All-or-nothing
The extracellular concentration of sodium ions is [greater or less] than the intracellular concentration
greater
______ ______ and ________ can affect gene expression
steroid hormones; methylation
______ ________ & _________ affect gene expression
steroid hormones; methylation
______ ________ bind with nuclear receptors that regulate expression through transcription factors
steroid hormones
__________ is a DNA-level covalent modification that is an example of epigenetics
Methylation
______ ________ bind to membrane receptors and trigger intracellular signaling cascades that dramatically impact cellular activity
peptide hormones
At the peak of an action potential, the membrane potential of the neuron is approximately ___ mV
+40
______ ceases to flow into the cell, while voltage-gated ________ channels open to allow ________ to flow out of the cell
sodium; potassium; potassium
What is the function of the basal ganglia?
controls fine motor movements
What is the function of the inferior colliculus?
transmits signals to the medial geniculate nucleus located within the thalamus
What is hyperpolarization?
a state in which the membrane potential is more negative than its resting value
when ________ ions are positive, their exit from the cell would make its interior more ________
potassium; negative
What are the four functions of insulin?
stimulates glycogenesis, increases triglyceride synthesis, decreases fatty acid oxidation, and facilitates the uptake of glucose into muscle, adipose, and other cells
In females, a surge of LH causes what between days 11 and 21 of the menstrual cycle?
causes mature follicles on the ovary to undergo ovulation
What is the role of LH in males?
LH binds to its receptors on Leydig cells, stimulating testosterone synthesis and secretion
A paracrine agent acts on what?
nearby cells
Autocrine agents act on what?
the cell that secreted them
Exocrine activity involves what?
the secretion of products through ducts
The thyroid-stimulating hormone is secreted by one gland?
anterior pituitary gland
TSH acts on the thyroid gland to promote the secretion of which two hormones?
thyroxine (T4) and triiodothyronine (T3)
What is the function of thyroxine (T4) and triiodothyronine (T3) hormones?
increase the metabolic rate of nearly every cell in the body
What are the two functions of the adrenal mineralocorticoid?
acts on the distal tubules and collecting ducts of the kidney nephron and stimulates sodium retention and potassium secretion
The adrenal mineralocorticoid promotes what in the presence of ADH?
water retention
Calcium ions, cAMP, and cGMP are all common ______ __________
second messengers
True or False: ATP is considered a second messenger
False
Insulin is produced in what kinds of cells?
ꞵ cells
Glucagon is produced in what kinds of cells?
ɑ cells
Somatostatin is produced in what kinds of cells?
delta cells
Epsilon cells produce what hormone?
ghrelin
Corticotropin-releasing hormone (CRH) is secreted by what structure?
hypothalamus
Adrenocorticotropic hormone (ACTH) is released by what gland?
anterior pituitary gland
What is the function of ACTH?
acts on the adrenal cortex to release cortisol
Name the molecule corresponding to this structure
estradiol
·O₂⁻, ·OH, & H₂O₂ are all examples of what?
reactive oxygen species
Vitamin E is an ___________
antioxidant
What is the order of events in the developmental process of oocytes?
Meiosis I initiation → meiosis I completion → puberty →meiosis II initiation → fertilization → meiosis II completion
What are the seven steps of the ejaculatory pathway of sperm?
Seminiferous tubules, epididymis, vas deferens, ejaculatory ducts, urethra, penis (think: SEVE(n) UP)
Ovulation in which diploid primary oocytes mature into haploid secondary oocytes occurs when?
after puberty
The variability of the menstrual cycle is due to what phase?
follicular phase
What is another word for the follicular phase?
proliferative phase
The luteal phase lasts for how many days in the menstrual cycle?
14 days
What is another word for the luteal phase?
the secretory phase
What is the order of the stages of embryonic development from earliest to latest?
Morula, blastula, gastrula, neurulation
What hormone mimics LH and maintains the corpus luteum to maintain estrogen and progesterone levels?
Human chorionic gonadotropin (hCG)
hCG is what kind of hormone?
peptide hormone
What 3 factors causes acidosis due to extended cardiac arrest?
reduced gas exchange, increased serum [CO2], and increased lactic acid production due to anaerobic metabolism
After gas exchange in the tissues, blood typically has a higher ______ ________ content, a lower ______ content, and a lower __
carbon dioxide; oxygen; pH
What two blood vessels carry deoxygenated blood from the right side of the heart to the lungs to be oxygenated in the lungs?
systemic veins and pulmonary arteries
What blood vessels return oxygenated blood to the heart?
pulmonary veins
What structures provide electrical conduction to the ventricles?
Purkinje fibers
What is the name of the hormone released from blood platelets?
thromboxane
What is the name of the enzyme in blood plasma that causes the clotting of blood by converting fibrinogen to fibrin?
thrombin
Active exhalation involves contraction of what muscles?
internal intercostal muscles
Contraction of the diaphragm is associated with [inhalation or exhalation]?
inhalation
What is residual volume?
volume of air remaining in the lungs after an individual has exhaled as much as possible
How does the epiglottis protect the lungs?
closes while eating to protect the lungs from swallowed objects
Where is surfactant found and function does it serve?
in the alveoli and serves to reduce surface tension
What cells produce mucus?
goblet cells
Hyperventilation can markedly [increase or decrease] the amount of carbon dioxide in the blood
decrease
What kinds of receptors stimulate ventilation in response to increased arterial carbon dioxide levels?
carbon dioxide-sensing chemoreceptors
What form of transport is used to exchange gases between the alveoli and the capillaries?
simple diffusion
Individuals can only receive blood if [statement]
it does not contain antigens that the recipient makes antibodies against
What is required to have a net filtration pressure?
the net pressure must favor movement of fluid from the capillary into the Bowman’s space
The fluid movement into the Bowman’s space is [positive or negative]
positive
The fluid movement into the glomerular capillary is [positive or negative]
negative
What part of the nephron accounts for the majority of transport along the nephron?
the proximal tubule
The descending loop of Henle only allows for [passive or active] reabsorption of water
passive
The ascending loop of Henle is [permeable or impermeable] to water, and has to [passively or actively] pump ions out of the nephron
impermeable; actively
__% of our sample values to fall within 1 standard deviation of the population mean
68
__% would fall within 2 standard deviations
95
__% of the sample values will be within 3 standard deviations of the population mean
99.7
What is oncotic pressure?
a form of osmotic pressure exerted by proteins in a blood vessel’s plasma
What are the four major proteins in the blood & they each comprise how much % of the blood?
albumins (55%), globulins (38%), fibrinogen, also known as clotting factor I (7%), and clotting factors (<1%)
What are the two primary effects of aldosterone?
increases sodium absorption in the distal convoluted tubule and collecting duct of the nephron and causes fluid retention increasing the blood pressure
What is the function of the gallbladder?
releases stored bile into the small intestine to help emulsify fats
___________ are broken down in the small intestine by enzymes known as _______________
disaccharides; disaccharidases
The pancreas is the source of the zymogen form of ______, a ________
trypsin; protease
Starch is partially digested in the mouth by what enzyme?
salivary amylase
What organ is typically the site of the absorption of significant amounts of water into the body?
large intestine
Since cellulose cannot be digested or absorbed, it will remain in the digestive tract, [increasing or decreasing] its osmolarity and [increasing or reducing] the concentration gradient of water
increasing; reducing
Vasopressin activity results in what?
retention of water via reabsorption in the collecting duct of the nephron
A vasopressin receptor antagonist [increases or decreases] water retention, & [increases or reduces] blood volume
decreases; reduces
What is the function of the proximal convoluted tubule?
the site of major reabsorption and secretion that is largely driven by sodium transport
What is the function of the distal convoluted tubule?
involved with hormone-controlled reabsorption and secretion
What is the function of the Loop of Henle?
create an osmotic gradient
What is the function of the collecting duct?
create a concentration of urine
What sphincter is composed of skeletal muscle and is under voluntary control?
external anal sphincter
What sphincter (there are 2 names) separates the esophagus from the stomach and is under involuntary control?
the gastroesophageal sphincter or the cardiac sphincter
What sphincter separates the stomach from the small intestine and is involuntary?
the pyloric sphincter
Why are proteins not typically found in urine?
Because they are too large to pass from the blood stream into the filtrate at the nephron
True or False: Ketones are normally found in urine
False, ketones are not normally found in urine
The presence of ketones in urine is associated with what condition?
diabetes
Immunosuppression [increases or decreases] the risk of cancer
increases
What is the variable region?
the amino acid sequence that is complementary to the antigenic sequence
Antigens bind to the variable region through what kinds of interactions?
noncovalent interactions
The blood-brain barrier is formed by what?
capillary endothelial cells
What are tight junctions?
closely associated regions of adjacent cells that form a virtually impermeable barrier to fluid
True or False: Iron is present in carbonic anhydrase
False, iron is not present in carbonic anhydrase
What is carbonic anhydrase?
a metalloenzyme that catalyzes the reversible reaction between carbon dioxide and water
The active site of carbonic anhydrase contains a ____ molecule
zinc
Respectively, labels A, B, and C refer to
the renal medulla, the renal cortex, and a ureter
What kind of selection occurs when the population’s alleles are seen to favor more extreme phenotypes over time?
disruptive selection
What are centromeres?
heterochromatin-based regions of DNA that assist in the connection of sister chromatids
What is transformation?
taking up extraneous information from the environment
________ are used in lab settings to incorporate genes of interest into certain cells.
Plasmids
What is hyperpolarization?
when the neuron’s potential is dropping to a more negative value
What is hyperpolarization?
when the neuron’s potential is dropping to a more negative value
What is anterior-posterior patterning?
changing the poles or zone of polarizing activity
What is the function of limb-specific transcription factors?
activate the transcription of specific genes to initiate differentiation
What is the function of limb-specific transcription factors?
activate the transcription of specific genes to initiate differentiation
An embryo becomes a fetus by the ___ week of development
9th
The region marked 2 corresponds to what part of the antibody?
the antigen-binding domain or variable domain
What purpose does the variable domain serve?
allows antibodies to recognize very specific antigens
What purpose does the variable domain serve?
allows antibodies to recognize very specific antigens
Carbon dioxide is a ________ of hemoglobin that binds to the active heme group
substrate
Hemoglobin is an iron-containing _____________
metalloprotein
Circular loops or linear strands of ssDNA pertain to what organisms?
viruses
Linear strands of dsDNA pertain to what organisms?
humans
Circular loops of dsDNA pertain to what organisms?
bacteria
True or False: Erythrocytes are anucleate & incapable of synthesizing new proteins
True
True or False: Erythrocytes are able to produce MHC
False, erythrocytes are unable to produce MHC and do not express it under any circumstances
What happens in the first reaction of integration?
integrase cleaves a dinucleotide from the 3’ end of a strand of viral DNA
Cleaving a dinucleotide from the 3’ end of a strand of viral DNA involves the cleavage of a ___ bond
P-O
mRNA transcribed from retroviral DNA can be used in what two ways?
to synthesize viral proteins or used as the RNA genome for progeny viruses
What is the average molecular weight of an amino acid?
110 Da
What is the average molecular weight of an amino acid?
110 Da
What is necessary for confirming that a small molecule induces the formation of integrase tetramers from integrase dimers?
visualize the proteins in their native state
What is the consequence of using a denaturing agent?
disrupts the interactions between monomers
What is the consequence of using a reducing agent?
disrupts any disulfide bonds
Na⁺ reabsorption is of utmost importance to the function of what organ?
the loop of Henle
Na⁺ reabsorption is of utmost importance to the function of what organ?
the loop of Henle
The loop of Henle is where…
Na⁺ is reabsorbed from the filtrate moving through the nephron
What causes the depolarization of the neuron that occurs during the action potential?
the massive influx of sodium through voltage gated ion channels
Glycolysis produces ___ ATP molecules per glucose molecule
2
Glycolysis produces ___ ATP molecules per glucose molecule
2
How many Na⁺ molecules are extruded for each ATP molecule utilized by the sodium pump?
3 Na⁺ molecules
The protection of glucose in this harsh environment is due to what?
its effects on the diffusion of water
Hyperglycemia normally elicits [insulin or glucagon] secretion
insulin
[Glucagon or Insulin] secretion is suppressed by hyperglycemia
Glucagon
What feature of RNA makes RNA more reactive and unstable than its DNA counterparts?
the presence of a 2’ hydroxyl group on ribose
What feature of RNA makes RNA more reactive and unstable than its DNA counterparts?
the presence of a 2’ hydroxyl group on ribose
What is the typical resting potential of a neuron?
-45 mV
What is the typical resting potential of a neuron?
-45 mV
True or False: Prokaryotic translation does rely on the presence of several release factors
True
What release factor do eukaryotes need?
eukaryotic translation termination factor 1 (eRF1)
Protozoans are [eukaryotic or prokaryotic] organisms
eukaryotic
The cardiac muscle tissue has an action potential with a “_______” in its depolarization whereas the skeletal muscle tissue does not have a “_______.”
plateau; plateau
Repolarization is delayed due to what?
the action of slow-to-open voltage gated Ca2+ channels
the opening of K+ channels in skeletal muscle tissue is able to [slowly or rapidly] repolarize the cell
rapidly
What kind of molecule is myoglobin and what is its role?
monomeric and plays an analogous role in maintaining an oxygen reserve in the tissues
What are restriction endonucleases?
enzymes that cut DNA at specific sites
Restriction endonucleases are used in an early step of ________ ________ procedure, and they can also be utilized to cleave DNA as part of a ______ _______
Southern blotting; repair process
The mesodermal layer gives rise to what three structures?
the skeletal system, the cardiovascular system, and the kidneys
When traveling from the cortex towards the inside of the body or the medulla, the solute concentration [increases or decreases]
increases
True or False: Neurons, epithelial cells, and fat cells would be expected to have a high actin concentration
False, neurons, epithelial cells, and fat cells would not be expected to have a high actin concentration
What types of cells should have the highest concentration of actin and myosin?
muscle cells
What types of cells should have the highest concentration of actin and myosin?
muscle cells
The ______ is the area of the nucleus where the genes that code for ribosomal RNA (rRNA) are transcribed
nucleolus
What is one of the functions of the liver?
drug detoxification
Stabilizing selection generally results from what?
forces favoring moderate phenotypes over extreme ones
When does the bottleneck effect occur?
a disaster or other event results in a loss of a large portion of a population. All future members of a population then descend from a small number of individuals
Glucagon increases gluconeogenesis in the _____ and _______ only
liver; kidneys
Between meals, glucagon stimulates enzymes in the liver to break down _______ ______ so that glucose can be released into the bloodstream
glycogen stores
What is the function of aldosterone?
causes increased absorption of sodium and water
True or False: Aldosterone is a fast-acting hormone
False, aldosterone is not a fast-acting hormone
Vasopressin is also known as what?
ADH
What is vasopressin (or ADH)?
a fast-acting hormone that increases water reabsorption in the collecting ducts of nephrons in the kidneys. It concentrates urine and results in less frequent urination
The endoderm gives rise to what?
linings of internal organs (stomach, lungs, intestines, etc.)
What structures differentiate from the ectoderm?
epidermis, nervous system, eye lens, and hair
What structures differentiate from the mesoderm?
muscle, cardiac and skeletal systems, blood, heart, and spleen
The pulmonary veins are adjacent to what structure?
the left atrium
Pulmonary veins receive __________ blood from lungs and carry it back to the _____
oxygenated; heart
RNA pol I transcribes certain genes into what type of RNA molecule?
rRNA
What is lineage potential?
the ability to differentiate into many cell types
What is lineage potential?
the ability to differentiate into many cell types
As pluripotent cells develop into multipotent cells, they express a [greater, equal, or smaller] percentage of lineage-specific genes due to specialization
greater
What is one of the mechanisms used to “turn off” genes not related to newly specialized cells?
DNA methylation
In eukaryotes, dsDNA is wrapped around proteins known as what?
histones
A DNA-histone subunit is termed a __________
nucleosome
Chromatin represents what?
fully packed DNA
True or False: Selection pressures can decrease the frequency of a trait even if that trait is not negative and the pressure is not acting directly on that trait
True
The term, “wild type,” refers to what?
traits an animal typically possesses when found in nature
____ ____ usually refers to a dominant trait but not always
wild type
What is the epiglottis and what is its function?
a piece of connective tissue that covers the trachea when swallowing food to ensure food goes down the esophagus
What structure connects the esophagus to the stomach?
the cardiac sphincter
Dyneins carry cargo towards the [ends or center] of the cell
center
Where is the microtubule organizing center (MTOC) located?
close to the center of the cell
Microtubules grow from the [positive or negative] end, so the end is located towards the periphery of the cell while the [positive or negative] ends are found close to the center
positive; negative
Kinesins travel toward the [positive or negative] ends of microtubules
positive
What is the likelihood of independent assortment for genes on different chromosomes?
50%
Lipase’s ability to catalyze the hydrolysis of fats and similar molecules reveals what?
some enzymes interact with several different substrate molecules that have similar chemical linkages
Upon undergoing meiosis and distributed to the cytoplasm to two daughter cells, most of it goes to the daughter cell destined to be the ____
ovum
The daughter cells that are cast off with little cytoplasm are called what?
polar bodies
An antisense drug works to prevent what?
the expression of undesirable genes
What is the only way to cure PKU?
add a gene that could lead to the production of effective enzymes to replace the ones that do not function correctly
The coordination of cell differentiation during development is extremely sensitive to what?
the timing of mRNA turnover
Prolonged increase in heart rate and breathing rate is caused by what?
insufficient blood hemoglobin to supply oxygen for exercise at low oxygen pressure found at high altitudes
What is myoglobin?
the substance that holds oxygen in the muscles and organs
During anaphase of mitosis, sister chromatids are pulled apart at the ____________, each becoming an independent chromosome in the two diploid daughter cells
centromeres
What happens during anaphase I of meiosis I?
homologous pairs of chromosomes are separated into two daughter cells
The centromere is split and the sister chromatids separate during what phase of meiosis II?
anaphase II
Regions 1,3, and 4 refer to what?
heavy chains
This is the structure of what molecule?
serine
