DAT Booster Biology Practice Exam 3 Flashcards
Which of the following would be present in both a virus and E. Coli bacteria?
nucleic acids
viruses contain:
nucleic acids (RNA or DNA)
single or double stranded
capsid composed of proteins enclosing nucleic acid
spike proteins made of glycoproteins and viral envelope
lack metabolisms
bacteria contain:
single
circular
double stranded DNA
ribosomes
flagella
cell wall
Which of the following organisms were the first to produce oxygen on Earth?
cyanobacteria
protozoa
single celled
eukaryotic
membrane bound organelles
heterotrophic and parasitic
fungi
eukaryotic
heterotrophs
feed on dead matter
diploid or haploid ( dominates )
sexual and asexual reproduction
filamentous or non filamentous
unable to produce oxygen
Slime molds are
fungus-like protists.
feed on dead matter and form filaments like fungi do.
capable of locomotion.
heterotrophic
do not perform photosynthesis which produces oxygen.
dermis
deep to the epidermis and is the second layer that comprises the skin.
composed of connective tissue, collagen, and elastic fibers.
contains hair follicles, glands, nerves, and blood vessels.
two layers that comprise the dermis: the papillary dermis and the reticular dermis.
The papillary dermis makes up the
20% of the dermis and is a highly vascularized layer with upward projecting papillae that supply nutrients to the avascular epidermis layer above.
The papillary dermis also contains Meisner’s corpuscles which are sensory touch receptors.
The reticular dermis
the region composed of dense irregular connective tissue, collagen, and elastic fibers.
The reticular dermis contains glands, fat, sweat gland ducts, and hair follicles. The reticular dermis is the layer that gives the dermis its strength and elasticity
In the absence of oxygen, E. coli will undergo
fermentation and glycolysis in order to continue to make ATP
The cell spends the vast majority of its time in
interphase
Interphase is the stage of the cell cycle where the cell is not dividing but
preparing for cellular division
During the cell cycle, there are important checkpoints that ensure the cell cycle is operating as planned. Two of these important checkpoints occur during
interphase
Interphase can be further broken down into
Gap Phase 1 (G1), Synthesis Phase (S), and Gap Phase 2 (G2).
During Gap Phase 1 (G1), the cell
Increases in size and many proteins and organelles are synthesized.
The first important cell cycle checkpoint occurs at the end of G1.
This checkpoint ensures that everything is ready for DNA synthesis, which occurs in S phase.
If the G1 checkpoint decides that conditions are unfavorable for DNA synthesis, the cell will enter G0.
Synthesis Phase (S phase).
During the S phase, the cell will replicate its genome in preparation for a cellular division event. After S phase is complete, cells will move on to gap phase 2 (G2)
Gap Phase 2 (G2)
rapid cellular growth occurs, organelles are replicated, and genetic material prepares for cell division.
The second cell cycle checkpoint occurs during G2 as well.
During this checkpoint, the cell will check for adequate levels of Mitosis Promoting Factor (MPF).
The cell also checks for the accuracy of DNA replication. S
o long as the cell passes the G2 checkpoint, the cell will continue to M Phase.
M phase
M Phase stands for mitosis or meiosis, which are both important cellular division processes that you should understand in detail for your test. If you do not fully understand all stages of mitosis and meiosis, it is highly suggested that you return to the bio notes and study these processes in full.
examples of eukaryotes
protista
plantae
fungi
animalia
examples of prokaryotes
archaea
eubacteria
Which of the following ions are regulated by the sarcoplasmic reticulum of striated muscle cells?
calcium ions
The sarcoplasmic reticulum
unique endoplasmic reticulum found in muscle fibers.
The sliding filament theory
begins when a presynaptic motor neuron delivers its action potential to the postsynaptic muscle fiber.
presynaptic motor neuron will synapse with the postsynaptic muscle fiber and release acetylcholine into the neuromuscular junction.
The neuromuscular junction is the space between the neuromuscular motor neuron and the postsynaptic muscle fiber.
This acetylcholine will lead to sodium channels on the muscle fiber to open.
This leads to an influx of sodium ions which will depolarize the cell and lead to the firing of an action potential.
Once the action potential has been initiated, the action potential will travel along the T-tubules until it meets the sarcoplasmic reticulum.
Once the depolarization reaches the sarcoplasmic reticulum, it will lead to the opening of voltage-gated calcium channels. This calcium will be released from the sarcoplasmic reticulum and will bind to troponin, causing troponin to remove tropomyosin from the binding site on actin. Once the binding sites on actin are exposed, the myosin heads are able to bind to the actin and pull it towards the center of the sarcomere, stimulating muscle contraction!
depolarization
Na+ channels are opened, K+ channels are closed
Once the neuron receives a stimulus, it causes gated ion channels to open resulting in an influx of Na+ ions
This influx of positively charged ions increases the membrane potential of the neuron
If the stimulus is strong enough, the membrane potential will reach threshold value (-55mV) and an action potential will fire.
limbic system
comprised of the hypothalamus, hippocampus, and amygdala.
learning and memory, emotion, the regulation of thirst, hunger, temperature, libido, and motivation.
cerebellum
is responsible for hand-eye coordination.
primarily responsible for motor control, balance, and coordination.
what makes up the limbic system
amygdala, the hypothalamus, and the hippocampus
amygdala plays a major role in the regulation of
emotions such as fear, anxiety, sadness, and anger.
emotional memory
Medulla oblongata
one of the structures of the brainstem. The medulla oblongata plays a major role in the regulation of breathing, heart rate, and gastrointestinal activity.
Occipital lobe
The occipital lobe is responsible for the processing of visual input, object recognition, and the responding to visual stimuli.
During a contraction of the heart, a wave of depolarization will be sent through which correct sequence of structures?
Sinoatrial node → Atrioventricular node → Bundle of His → Purkinje fibers
Transformation
whereby bacteria will take in DNA from surroundings and incorporate it into the genome.
Transformation is the process by which extracellular DNA is taken up and incorporated into a bacterium’s genome
Only competent bacteria are capable of transformation. Competency refers to the ability that a bacterium has to undergo transformation.
Transduction
Transduction is the transfer of genetic material from one bacterium to the next via a virus. Once a virus infects a host bacterium, that virus will begin to replicate. Some of the bacterial host’s DNA will be incorporated in the new virus particles. When these new virus particles infect a separate bacterium, some of the foreign DNA will be transferred to the new host.
Conjugation
Conjugation is a horizontal gene transfer technique whereby a donor bacterium creates a bridge (pilus) that connects to a recipient bacterium. This pilus is used to transfer genetic material from the donor to the host. In the scenario in question, the E. coli and the H. pylori were never in the solution together at the same time. This would make conjugation impossible between the two bacteria.
The main purpose of aldosterone is to
increase BP
Juxtaglomerular cells near the glomerulus of the nephron will detect low blood pressure and release
renin
Renin (an enzyme) will conver
angiotensinogen into angiotensin I.
Angiotensin Converting Enzyme (ACE) will convert angiotensin I into angiotensin II.
Angiotensin II will lead to an increase in aldosterone secretion from the adrenal cortex.
So how exactly does aldosterone increase blood pressure?
Aldosterone acts on the distal convoluted tubule and the collecting duct of the nephron. Aldosterone will work to increase sodium (Na+) reabsorption and potassium (K+) secretion. When sodium is reabsorbed into the circulation, water will follow. This ultimately leads to an increase in blood volume and pressure!
Yeast
single-celled
kingdom Fungi
Yeast are nonfilamentous fungi
capable of reproducing asexually via budding.
Yeast possess a cell wall made of chitin and can utilize aerobic respiration or fermentation when oxygen is absent.
In this way, yeast are facultative anaerobes.
As an embryo develops from a zygote to a blastula, there is a reduction in cell size. Which of the following explains this phenomenon?
The amount of cytoplasm within each cell decreases after each cellular division
Non-disjunction
the failure of one or multiple chromosome pairs to separate during anaphase.
Nondisjunction may occur during meiosis I, which results in the failure of homologous dyads to separate. Nondisjunction can also occur during meiosis II, which results in a failure of identical sister chromatids to separate.
And finally, nondisjunction can occur during mitosis, which, similar to nondisjunction in meiosis II, results in the failure of identical sister chromatids to separate.
Nonsense mutation
A nonsense mutation is a change in the DNA code such that the original codon that has been altered now codes for the stop codon (UAA, UAG, or UGA).
stop codon results in a shorter polypeptide chain which can have drastic effects on the protein’s function.
A species is best defined by the fact that it is _____________.
Isolated reproductively
Which of the following would trigger an intracellular response?
four secondary messengers:
cyclic AMP (cAMP)
inositol triphosphate (IP3)
diacylglycerol (DAG)
calcium ions (Ca2+).
some hormones are lipophilic (lipid-soluble):
Steroid hormones, like testosterone and estrogen, are lipophilic and therefore, can freely diffuse across the cell membrane.
certain tyrosine-derived hormones like thyroxine (T4) and triiodothyronine (T3)
hydrophilic (water-soluble) hormones are unable to freely diffuse across the cell membrane:
Peptide hormones, like follicle-stimulating hormone (FSH) and antidiuretic hormone (ADH) are hydrophilic and therefore, cannot freely diffuse across the cell membrane
Enzymes
accelerate chemical reactions.
catalysts
Enzymes can either be proteins or RNA macromolecules (ribozymes).
allow reactions to occur faster by taking an alternative reaction pathway that has lower activation energy
enzymes allow equilibrium to be achieved at a faster rate.
only change the energy of the transition state of a reaction.
Enzymes are not capable of making a non-spontaneous reaction into a spontaneous one.
not used up during a reaction, therefore, they are not considered reactants.
enzyme can be used over and over again to continuously catalyze chemical reactions.
enzymes have an active site where reactants are able to bind and unbind
bind to substrates via weak, non-covalent bonds which is why substrates can unbind to enzymes with relative ease. Enzymes are substrate-specific and can only be bound to certain substrates.
not ‘used up’ during the reaction.
How many nucleotides are required to make 90 codons?
A codon is a sequence of three nucleotides that codes for a specific amino acid. Below is a chart that shows which amino acids are coded by each specific codon. Recall that amino acids are the monomeric subunit of proteins. The ribosome will read each codon and synthesize the corresponding amino acid. These amino acids are connected via peptide bonds in order to make a polypeptide chain. This is how proteins are synthesized!
The question here asks how many nucleotides is needed to make 90 codons. We know that each codon is made from three nucleotides so to answer this question, we simply have to multiply
90 x 3 = 270 nucleotides
steroid hormones are lipophilic, therefore, they are permeable. Examples
steroid hormones include cortisol, aldosterone, estrogen, testosterone, and progesterone.
Peptide hormones are hydrophilic and therefore, are not permeable to the cell membrane. Examples of peptide hormones include
include insulin and glucagon (among many others).
Catecholamines like epinephrine and norepinephrine, on the other hand, are hydrophilic (water-soluble) and therefore,
are impermeable to the cell membrane.
What structure of angiosperms does pollen land on during pollination?
stigma
three different methods of horizontal gene transfer that you’ll need to know for your test:
- Conjugation
- Transformation
- Transduction
The primary function of the small intestine is
digestion and absorption of the food we eat.
In the small intestine, carbohydrates are broken down into simple sugars, proteins are broken down into amino acids, and fats are broken down into fatty acids and glycerol.
These nutrients are then readily absorbed in the small intestine for use within the body.
Large intestine
The large intestine is primarily responsible for water absorption, mineral absorption, and the production of vitamin B and vitamin K.
Pancreas
The pancreas has both endocrine and exocrine functionality. The endocrine function of the pancreas is the production and secretion of insulin, glucagon, and somatostatin. The exocrine function of the pancreas includes the secretion of pancreatic amylase, pancreatic lipase, trypsinogen, chymotrypsinogen, and bicarbonate into the small intestine to aid in digestion.
