DAT Booster Biology Practice Exam 6 Flashcards
A botanist has discovered a new plant and notes that it is predominantly found in its gametophyte form. Which category does this plant most likely belong to?
bryophyte
All land plants undergo reproduction with an
alternation of generations
alternation of generations scheme
alternates between sexual and asexual reproduction stages
tracheophytes (including seedless tracheophytes, and seeded angiosperms, and gymnosperms) are found most prominently in the
diploid sporophyte phase
bryophytes are found most prominently in their
gametophyte phase
The endosperm is not a plant, but rather a specific type of supportive tissue that
provides nutrition to the developing embryo.
Double fertilization
found in most angiosperms and results when two sperm from a pollen grain fertilizes one polar nuclei, a degenerate egg.
main egg that is fertilized by a single sperm goes on to form the diploid zygote.
seedless tracheophytes have
vascular structures, and it should be noted that plants that have a dominant gametophyte generation will lack true vascular structure.
In the fetal circulatory system, the ductus venosus allows blood to bypass which of the following?
liver
As oxygenated and nutrient-rich blood returns to the fetus from the placenta via the umbilical vein, half enters the
ductus venosus.
bypasses the liver as blood returns to the heart. The liver in adults acts to filter and detoxify the blood but is not fully functional during early development.
Which of the following would be the most immediate consequence of a defective sperm without an acrosome reaching the egg for fertilization?
inability to penetrate zona pellucida
acrosome
the head of the sperm and it contains hydrolytic enzymes that allow sperm to digest through the zona pellucida to get to the oocyte.
a mutation in the acrosomal vesicle would prevent sperm from penetrating the zona pellucida in order to reach an oocyte, fuse cell bodies and share its genetic material.
IgA
found in mucous, saliva, and breast milk
dimer consisting of two subunits
protects against pathogens
IgD
part of the B cell receptor
activates basophils and mast cells
IgE
protects against parasitic worms
responsible for allergic reactions
IgG
secreted by plasma cells in the blood
able to cross the placenta into the fetus
IgM
may be attached to the surface of a B cell or secreted into the blood
pentamer consisting of five subunits.
responsible for early stages of immunity
What process immediately follows the penetration of the corona radiata by sperm?
Acrosomal reaction
After a sperm penetrates an egg’s outer corona radiata layer
the sperm binds to the ZP3 protein of the zona pellucida to enable mutual recognition of species-compatible gametes.
This binding to the ZP3 protein enables the acrosomal reaction to occur and initiates the start of fertilization.
The release of acrosomal digestive enzymes allows the sperm to further penetrate the zona pellucida to fuse with the egg’s plasma membrane to deposit its nucleus into the egg.
same time the sperm binds to ZP3, the fast block of polyspermy occurs to trigger an influx of Na+ that prevents additional sperm from binding to ZP3
Capacitation
capacitation occurs while the egg is in the uterus due to uterine chemicals.
This process increases the permeability of the acrosome and increases the activity of the flagella before the sperm reaches the egg.
Once implantation occurs, the placenta starts secreting
human chorionic gonadotrophin (hCG)
human chorionic gonadotrophin (hCG)
maintains the corpus luteum.
corpus luteum secretes
estrogen and progesterone
when implantation does not occur,
the corpus luteum degenerates and as estrogen and progesterone levels drop, the endometrium is shed as menstrual flow.
estrogen and progesterone are needed to maintain the
endometrium
an LH spike is required
for ovulation
Archenteron
archenteron is a primitive digestive cavity of the embryo at the gastrula stage of development in animals.
formed by the invagination of mesoderm and endoderm cells, opens to the outside by a blastopore, and finally develops into the gut cavity.
operon
set of structural and regulatory genes controlled by a promoter and an operator.
Lac Operon in E. coli controls the breakdown of
lactose
Three structural genes, ___ ___ ____, code for enzyme involved in lactose digestion
Lac Z, Y, A
When lactose is available, LacZ turns
lactose into allolactose, which binds to the repressor and inactivates it, allowing RNA polymerase to attach and transcribe the genes.
enzymes for lactose breakdown are only produced when lactose is actually available.
A woman using human chorionic gonadotropin during fertility treatment would expect to see stimulated production of which hormone as a direct result?
progesterone
A woman undergoing fertility treatment would expect to see increased production of estrogen and progesterone because of
using human chorionic gonadotropic (HCG).
Allopatric speciation is best described as which of the following?
Speciation that occurs after a population is divided geographically
Speciation that occurs without the presence of a geographic barrier
sympatric speciation
In response to low blood glucose levels, __________,
ACTH is released by the anterior pituitary
In response to low blood glucose levels, alpha cells of the pancreas in the islets of Langerhans secrete
glucagon into the bloodstream
increases blood glucose concentration by stimulating the breakdown of liver glycogen stores (glycogenolysis) and forming glucose from lactic acid and certain amino acids (gluconeogenesis)
he hypothalamus secretes CRH (corticotropin-releasing hormone) into the anterior pituitary, causing it to produce and secrete
ACTH (adrenocorticotropic hormone) into the bloodstream.
ACTH acts to increase the production of
glucocorticoids such as cortisol by the adrenal cortex, stimulating gluconeogenesis.
hGH increases the production of
IGFs (insulin-like growth factors) and stimulates glycogenolysis.
Which structure is the precursor for the androgens, estrogens, and progesterone molecules necessary for sexual development?
cholesterol
The sex hormones are part of a category of cholesterol-derived hormones known as
steroids.
What is an agent that is made and released in response to viruses?
interferon
Interleukins
interleukins are cytokines that regulate inflammatory and immune responses and are known to have antitumor properties.
All of the following are produced during glycolysis EXCEPT one. Which one is the EXCEPTION?
A. Pyruvate
B. ATP
C. NADH
D. ADP
E. NAD+
E
The development of structures in the appropriate segment along the head-tail axis is regulated by which of the following genes?
HOX
HOX genes
responsible for segmentation, by turning on and turning off certain genes in certain segments of the body.
affects what anatomic features develop in those segments.
The upper limit of action potential frequency is determined by __________.
Absolute refractory period
Which organism would be most affected if it were put in a solution with an enzyme that degraded chitin?
Yeast
Chitin is a beta-glucose polymer that functions as a structural molecule in
fungal cell walls and arthropod exoskeletons
Analogous structures are those resulting from
convergent evolution.
Which of the structures below is analogous with a bird’s wing?
Bat wing
A segment of DNA reads as follows: 5’ – ATATATGCGCACGC – 3’
What is the corresponding mRNA synthesized?
5’ – GCGUGCGCAUAUAU – 3’
Two species of monkeys emerge from a common ancestor. They live in the same jungle and are hunted by the same predators. Both species of monkeys have evolved prehensile tails and increased upper arm strength. Despite their similarities, they are not capable of interbreeding. Which form of evolution has taken place?
parallel
Fish gills are able to acquire sufficient oxygen despite being underwater. Why are most fish gills more efficient than land animals with lungs?
countercurrent exchange
Miller–Urey experiment
chemical experiment that simulated the conditions thought at the time to be present on early Earth and tested the chemical origin of life under those conditions.
Which of the following best describes the role of T-cells in the immune system?
cell mediated response
What contains the chromosomal DNA in a bacterium?
nucleoid
Which of the following proteins are most likely to be found in the extracellular matrix?
collagen
A man with type A+ blood had children with a woman with type AB– blood. All of the following are possible blood types they could have EXCEPT one. Which one is the EXCEPTION?
O+
Secondary messengers
molecules that relay signals received at receptors on the cell surface to target molecules in the cytosol and/or nucleus.
serve to greatly amplify the strength of the signal.
There are 3 major classes of secondary messengers to know for the DAT:
- Cyclic nucleotides (e.g., cAMP and cGMP)
- Inositol trisphosphate (IP3) and diacylglycerol (DAG)
- Calcium ions (Ca2+)
The broad use of antibiotics can result in __________.
vitamin deficiency
Broad-spectrum antibiotics, such as cephalosporins, are also known to reduce the absorption of
vitamin K in the body
During embryologic development, the stage that is best described as a hollow sphere of cells is called a __________.
blastula
An experiment on a nerve cell comes to an abrupt end due to an accidental mutation that disables the cell’s Na+/K+ pump. Which of the following would result from the lack of Na+/K+ pump function?
less sodium outside the cell
Taiga
taiga biome (also called boreal forest) has cold temperatures and little precipitation, which falls in the form of snow. This biome consists of coniferous forests.
Tundra
this biome has very low temperatures with little precipitation. There is very little vegetation as deeper soil is permafrost.
Savannas
biome is characterized by high temperatures, precipitation is less than in tropical rainforest. This biome consists of grasslands with scattered trees.
Temperate grasslands
this biome receives little precipitation, and as in the name, is temperate.
A cancer researcher wants to track a p53 protein related to tumor suppressor functions. Which technique could be used to locate this p53 protein within a cell?
Immunofluorescence staining
An E. Coli cell culture is radioactively labelled with sulfur and the cells are then lysed. Where would the radioactive label most likely be found?
proteins
Ovulation occurs due to a peak in
LH and FSH levels
Which of the following best describes cooperativity?
An enzyme becomes more or less receptive to additional substrate molecules after a substrate binds
skeletal muscle
multinucleated cells
form syncytium
striated and innervated by somatic nervous system
Cardiac muscle
striated, but is innervated by the autonomic nervous system. It is mononucleated or binucleated and exhibits properties of a functional syncytium due to its intercalated discs.
Smooth muscle
mononucleated but not striated. It does not form a syncytium, and it is innervated by the autonomic and the enteric nervous system.
Lobe-finned fish with lungs directly preceded which category of organisms?
amphibians
The plasma membrane is predominantly composed of which macromolecules?
Phospholipids and proteins
Increasing the amount of cholesterol in a plasma membrane would lead to an increase in _________.
Membrane fluidity at low temperatures
A parathyroid tumour, leading to hyperparathyroidism, would cause which of the following symptoms?
Increased bone fractures
Which of the following signalling molecule is used in the immune response to stimulate the development and activation of lymphocytes?
interluekin
Which of the following plant hormones promote fruit ripening?
ethylene
A random group of 200 black bears dissociate from a bigger population and settle in a region 100 km away. It is observed that the smaller group, along with their future generations, have a different fur type than the original population. What best describes this phenomenon?
Founder’s effect
bottleneck effect
describes allele frequency change due to catastrophic events
Consider a species whose chromosomal count is 2n. A non-disjunction has occurred in meiosis I of spermatogenesis, and the final sperm has fused with a healthy egg. Which of the following CANNOT be the zygotic or gametic genome?
it ended meiosis I with the gametic genotypes n+1 or n-1. Moreover, since it fused with a healthy egg, the final genotype is either 2n+1 or 2n-1.
2n+2 is not a possibility and must be the correct answer.
Question #40
A scientist accidentally mixes together bacterial, fungal, and plant cells in a petri dish. He will be able to correctly identify each of these cells by closely examining the composition of their __________.
cell wall
