Practice exam #1 test corrections

only content issue material

In terms of expressed genes in somatic cell and germline cells, which of the two cannot pass their genes/mutations to offspring

somatic cells

Exons vs introns

exons are spliced(not removed) and introns are removed from mRNA. Exons will code for proteins while introns will not. You will see exons in DNA, pre-mRNA, and mature mRNA, you will not see introns as they are removed. Exons contain the info that is translated into a protein—they’re EXpressed. Introns stay IN the nucleus before being removed from the coding sequence by RNA splicing.

Splice acceptor sites

they help spliceosomes know where to cut. theyre located at the end of an intron. When this site is recognized, the exons are spliced and introns are removed. If mutation occurs to this site, exons may not be recognized

mature mRNA

mature mRNA that is secreted or that will locate to the cell membrane will contain the signal sequence. It will not contain introns because they are removed, nor is a promoter

nuclear localization signal

a sequence that tags for it to be transported into the nucleus

Steroid

composed of a 6-6-6-5 fused ring assembly, which is a total of 4 fused rings

Neuron firing threshold

this threshold makes it more challenging for a neuron to fire an action potential. It is like a cap that tells the neuron to stop firing because the threshold has been reached.

Na+ K+ ATPase

This deals with ATP hydrolysis which involves ion concentrations and enzymes to produce ADP+Pi. This relates to enzyme activity, reaction rate/activity, it does not involve free energy because that discusses whether the transport is energetically favorable

What is the function of the Na⁺K⁺ ATPase during a neuronal action potential?

The restoration and maintenance of the resting potential relies on Na⁺/K⁺ ATPase. This is achieved by moving three Na⁺ out of the cell for every two K⁺ ions that are brought into the cell.

In which direction does the Na⁺K⁺ ATPase transport ions across the cell membrane upon ATP hydrolysis?

Upon ATP hydrolysis, three Na⁺ are transported outside the cell and two K⁺ are transported inside the cell against their concentration gradient.

what is p65 and cRel?

They are transcription factors. By definition, transcription factors regulate the expression of other genes by binding to the promoter or the enhancer of the gene located on the DNA

Identifying chemical compound structures to decide how it enters a cell

Charged molecules cannot diffuse through a membrane(Na+, K+, Ca2+, Cl-, HCO3-). They enter via ion channels, ion pumps, and transport proteins(charged=protein transport)

Polarity: If not charged, check for polarity. Polar molecules will have lots of O, N, OH groups, NH2 groups, and carbonyls. They dissolve well in water, but cannot cross hydrophobic membrane. So they require carrier proteins, facilitated diffusions, and active transport. Nonpolar compounds(like aromatic) will have a lot of C and H w/ few to no O or N. These only need simple diffusion.

Size: Small molecules are most likely nonpolar and will need simple diffusion. For larger molecules(DNA, proteins, polysaccharides), these need endocytosis, vesicles, receptor mediated endocytosis

protein kinases

they activate proteins via phosphorylation

proteolytic cleavage

when a protease cuts a larger protein into a smaller, active form

GTP binding

when a protein binds GTP to turn itself on

membrane association

a protein binds to or inserts into a membrane to function

Transcription factors

are proteins that turn genes off and on and decide which genes get made into mRNA. for these genes to be affected by specific transcription factors, they need to have the specific binding sites for them

what does ATPase activity(ATP hydrolysis) produce

ADP and inorganic phosphate(Pi)

Cholesterol-rich domains

small regions of the cell membrane that contain a high concentration of cholesterol and certain lipids- often called lipid rafts

The initial filtration step in the glomerulus of the mammalian kidney occurs primarily by:

glomerular capillary pressure, capsular hydrostatic pressure, and blood colloid osmotic pressure; The glomerular capillary pressure will force filtrate from a capillary into Bowman's capsule; the other two forces promote movement of the filtrate in the opposite direction. This process is not a countercurrent exchange system, and water and electrolytes are not actively transported from the glomerulus into bowman’s capsule.

Half life: If given the time it takes for urea to fall by 1/2= 0.5 hours, How long would it take for urea to be eliminated from the body given it takes 5 half lives

0.5 × 5= 2.5

Enzymes do their job by altering what

co-localizing substrates, altering pH of environment, and altering substrate’s shape. Altering the shape does not mean it alters its primary structure, that would mean it affects its amino acids

What is an enzyme

a biological catalyst that lowers activation energy, very specific, and cannot be used up. Usually ends in -ase

Enzymes: enzyme assay

used for measuring enzyme activity, it measures for its specific enzyme bc enzymes have specificity. Example: Ornithine decarboxylase assay is said to be highly specific, meaning it will measure ornithine decarboxylase activity only

What is needed to make more copies of a gene

mRNA; DNA, tRNA, and rRNA are not directly changed or correlated to making more of a protein via transcription.

Cell cycle: in which phase does no cell division occur

INTERPHASE; The order goes interphase→PMAT and if cells are growth arrested, this infers no cell division. There is cell division however in PMAT steps

Do erythrocytes contain DNA?

NO, and because they do not have DNA they cannot affect other cells via DNA

Reasoning about research design and execution: why would a researcher want to growth arrest cells in a mixture of different cells when performing a cell count?

It ensures that the only cells the researcher wants to divide are counted. Example: endothelial cells and supportive cells are mixed together and a cell count is performed electronically. Pericytes are growth arrested so to allow proper cell count

How are two nucleotides linked together

by a phosphodiester bond between the sugar base of one nucleotide(thymine) and the phosphate group of the adjacent nucleotide(adenine) in a way that the 5’ end bears a phosphate and the 3’ end a hydroxyl group

How does Addison’s disease affect the secretion of the hypothalamic factor(CRH)

A person with Addison’s disease cannot secrete glucocorticoids or mineralocorticoids, cortisol or aldosterone respectively. The hypothalamic factor stimulates the release of ACTH from pit. gland. ACTH triggers cortisol release, as cortisol levels increase, it will inhibit the hypothalamic factor(CRH), which stops the cycle. A person with addisons disease does not adequately secrete cortisol, therefore causing a continuous increase of hypothalamic factor in the body.

What is gluconeogenesis and what role does cortisol play in it

the process that forms glucose(a carbohydrate) when it is LOW. It does this by converting noncarbohydrates such as amino acids and lipids into glucose. Cortisol stimulates gluconeogenesis, so inhibiting cortisol will downregulate gluconeogenesis

glycolytic pathway: What role does insulin play in this pathway?

refers to glycolysis, the process of breaking down glucose IN CELLS. When insulin stimulates glycolysis(breaking down of glucose in cells) this results in a decrease of cellular concentration of glucose in the cell. Because there is less glucose INSIDE the cell, glucose uptake will increase to compensate for that change, therefore bringing in more glucose.

Which organelle would you see polypeptides being cleaved into mature form and secreted from the cell

Endomembrane system; this is referring to the ER and golgi apparatus in cells. They modify proteins(polypeptides) that will be secreted. Example: insulin cleavage is most likely to occur in the endomembrane system, not the nucleus, ribosomes, or cytoplasm.

Despite the effects of diabetes, the brains of diabetic patients still receive adequate nourishment. This is most likely because the brain uses:

insulin-independent transporters for the uptake of glucose; glucose is the main fuel for the brain, not fatty acids. The brain contains glucose transporters that are insulin independent. Meaning that the transporters do not need insulin in order to bind and transport glucose.

An RNA molecule has 1500 bases. What is the maximum number of amino acids it can encode?

A. 500

B. 1000

C. 1500

D. 4500

 amino acid is coded by 3 nucleobases, so when you’re give 1500 bases in a RNA molecule and want to know the max amount of a.a that it can encode then you divide 1500/3= 500

What functional group represents a peptide bond

An amide group

Describe gas liquid chromatography

2 phases: stationary liquid phase thats non polar and the mobile phase for gas. The compounds to elute first will most volatile(lowest BP) and has the weakest interaction with stationary phase aka less heavy—this will be the first peak. So, alcohols( 2-methyl-2-butanol), heavy compounds(2-Chloro-2-methylbutane or 2-Bromo-2-methylbutane) are examples of compounds that would NOT be your first peak. 2-Methyl-2-butene is an alkene, it has no H bonds, and has low molecular weight and BP, so it will elute first and be the first peak

SN1 vs SN2: how to identify/distinguish, product?, how do they each affect a compound

4 things to help you identify between SN1 and SN2 reactions is the substrate, nucleophile, solvent, and steric hindrance.

SN1 reactions: the substrate needs to be tertiary(mostly) or secondary. For tertiary substrates, the carbocation is stable and SN1 reactions can proceed(crowdedness doesn’t apply here). Weak nucleophiles are associated with SN1 reactions such ass H2O and alcohols(R-OH). For SN1 reactions, the solvent will polar protic, like H2O and alcohols bc they stabilize carbocations. SN1 reactions cause racemization products.

SN2 reactions: The substrates are methyl, primary, and secondary bc the carbocation isn’t stable(doesn’t like crowded carbons). SN2 reactions need strong nucleophiles like OH-, CN-, I-, Br-, SH-, and NH2-. Polar aprotic solvents favor SN2 reactions, DMSO, DMF, and acetone bc they dont trap the nucleophile. SN2 reactions cause inversion or a backside attack on carbocation, causing the product to switch from R to S/ S to R

R vs S configuration

R→ clockwise

S→ counterclockwise

The heaviest group/element is first then it goes down

Thin lens formula?

Used to determine the strength of a person’s eye lens. It states that the strength of a lens is equal to the inverse of the focal length of the eye lens.

1/O + 1/I= S; O being object’s distance and I being lens to retina distance. Example: A person, whose eye has a lens-to-retina distance of 2.0 cm, can only clearly see objects that are closer than 1.0 m away. What is the strength S of the person’s eye lens? First, convert 2.0 cm to m→ 0.02 m. Plug into formula: 1/1 + 1/0.02= 51

If someone wanted to decrease the ionization of a solution(e.g 1 M of acetic acid), what would have to be added?

you decrease ionization of a solution by adding acid aka H+. HCl is a strong acid that will decrease the % of acetic acid that ionizes. To INCREASE, you stabilize the conjugate base.

Note: electronegative atoms like Cl will increase ionization and diluting solutions increases % ionization.

Ohm’s law

says voltage(V) is equal to current(I) divided by resistance(R). Basically, whatever happens to voltage, the same will happen to the current when resistances is constant

Index of refraction

says that the IOR is equal to the ratio of the speed of light in vacuum to the speed of light in the medium. So say that the speed of light thru the vitreous humor is 2.1×10⁸ m/s. What is its IOR, given that the speed of light is 3.0×10⁸m/s? You divide SOL/IOR= 1.4 m/s

Energy of electromagnetic radiation and intensity radiation is directly proportional to what

the intensity of electromagnetic radiation is defined as the amount of energy emitted per unit time. This also means that the intensity is directly proportional to the number of protons emitted

Determine energy of a photon

Depending on what information is given, determines the formula used. If the frequency is given, use E=hv (h being a constant; v being frequency). If the wavelength is given, use E= hc/λ (h being a constant and λ being wavelength)

What percentage of standard atmospheric pressure is the pulse pressure of a healthy adult if the standard atmospheric pressure is 1 atm= 760mmHg and the normal adult pulse is 40mmHg.

Divide. (40mmHg/760mmHg) X 100= 6%

What fraction of a ¹⁵O sample decays in 10 min given its half life is 2min?

A. 1/8

B. 9/16

C. 3/4

D. 31/32

The question is asking how much of 15O is left after 10 minutes in a fraction given that its half life is 2 minutes. First, you divide 10/2= 5; this means that 5 half lives occur in 10 minutes for 15O. To find whats left, do 1/2⁵= 1/32

Formula for power

Power= W(T(s)) being W is work and T is time.

Example: What is the work generated by a healthy adult who circulates 9 L of blood through the brachial artery in 10 min?

A.2 kJ

B.12 kJ

C.20 kJ

D.120 kJ

9L has to be converted to mL→ 900mL(for context for this specific question)

Which a.a can form electrostatic interactions

Asp, Arg, Glu, Lys, His because they have charged side chains

Why are some gases sometimes called or to be considered “ideal gases”

A property of an "ideal" gas is that it is composed of particles that have negligible volume and do not exert intermolecular forces

Kinase vs ATP

Kinase is a type of enzyme that catalyzes the transfer of phosphate groups. In other words, it is the place where phosphate groups get exchanged. ATP is the phosphate donor or substrate, it will supply the phosphate to be transferred

Determining hybridization of an atom based on the compound

Linear compounds = sp

Trigonal planar = sp²; the central atom has 3 bonded atoms with no lone pair (three things bonded to it, but one of the bonds is a double bond)

Tetrahedral = sp³; no lone pairs with 4 bonded atoms (e.g CH4)

Trigonal pyramidal = sp³; 1 lone pair with 3 bonded atoms (NH3)

Bent = sp³; 2 lone pairs and 2 bonded atoms (H2O)

Tell me what enzyme catalyzes each reactions: ATP hydrolysis, peptide bond cleavage, hydrolysis of triacylglycerides, and transfer of carboxyl groups

ATPase- catalyzes ATP hydrolysis and is apart of the hydrolase class of enzymes

Protease/peptidase- catalyzes peptide bond cleavage and is apart of the hydrolase class of enzymes

Lipase- catalyzes the hydrolysis of triacylglycerides and is apart of the hydrolase class of enzymes

Carboxyltransferase- catalyzes the transfer of carboxyl group and is apart of the transferase class of enzymes

What is responsible for the branching of normal glycogen?

The bond a-1,6-glycosidic bond; a lack of this bond results in a sparsely branched glycogen structure

Solubility of an acid

The weaker acid, the less soluble it is in water. The strong acids: H2SO4, HI, HBr, HNO3, HCl, HClO4, and HClO3 (So I Brought NO Clean Clothes). Also, each successive proton is harder to remove in water. So if you have 2 weak acids such as HPO₄²⁻  and H₃PO₄. The high negative charge of HPO₄²⁻ makes it harder to dissociate in water. 

Gamma decay

gamma decay means the emission of photons by the nucleus

Purpose of catalyst

used to speed up the reaction and then need to be separated. If not separated, they can contaminate the product. The reaction would have already occurred, so it wouldn’t continue to increase the reaction rate

determining spontanaity of a reaction given the cathode and anode

the formula needed is Ecell= Ecathode - Eanode. The cathode is positive and anode is negative number. Once solved, if Ecell < 0, the the reaction is spontaneous, if not, its unspontaneous

Find voltage given resistance and current

formula: V=IR

Common ion effect

When  two reactants have a common ion(they share a ion), that will decrease the solubility or ionization and shift the equilibrium left. BaCrO₄ and Na₂CrO₄ have a common ion(CrO4). Because of this, this tells you that upon dissolution of Na₂CrO₄ would shift the equilibrium left.

Conversions:

1 M= 1 L/mol

1 L= 1000 mL

1 cm= 0.01 m

Relationship between power, work, and time

Power(W) is measured as energy/time in watts. So, 1W= 1J/1s. Since 1J= 1kg(m²)(s^-2), then so does 1W.

How to identify a compound (what questions to ask yourself)

1. nonpolar or polar?

2. Hydrophobic or hydrophilic

3. aromaticity

4. type of bonds present(intermolecular attraction)

Spreading activation

suggests when the representation of a concept is activated in memory, the activation spreads to concepts that are associatively related to it. Thus, people often retrieve unpresented members of a category when tested on their memory for a series of presented concepts from that category.

Classical Conditioning? What is conditioned stimuli? Unconditioned stimuli?

referring to providing a stimulus(conditional or unconditional) to achieve a certain reaction(conditional or unconditional response). This method is used to observe behavior and is closely related to the behaviorist approach.

Conditioned stimuli are previous neutral stimulus that gains the ability to trigger a response after being repeatedly paired with the unconditioned stimulus. In result, there is a conditioned response that is learned over time.

Unconditioned stimuli are natural stimulus that do not need to be learned to respond to because its automatic(e.g food or pain). An unconditioned response is the result of this because its an automatic reaction( e.g salivating or pulling away from whatever is causing the pain)

psychodynamic approach on behavior

The psychodynamic approach discusses that our thoughts, actions, and feelings are driven by unconscious motives and childhood experiences

positive punishment vs negative punishment

refers to the decrease in the frequency of a response resulting from the introduction of an aversive stimulus following that response.

Example: The patient describes the panic attacks as highly aversive and mentions he no longer goes to meetings for fear of a panic attack. Because the frequency of the patient's attendance at meetings has decreased as the result of the panic attacks, the panic attacks have acted as positive punishers.

Negative punishment refers to the decrease in the frequency of a response resulting from the removal of an appetitive stimulus following that response. The patient describes the panic attacks as highly aversive. In addition, they are introduced, rather than removed. Thus, the panic attacks do not match either of the criteria for negative punishers.

Describe the mechanism of the ear

Sound wave-induced vibration of hair cells generates tension within the cell membrane that directly activate ion channels responsible for auditory signaling. This type of ion channel is a mechanically-gated channel, such that upon its activation, it generates a depolarizing current within the cell.

Actor observer bias

when observing behavior in a situation, the actor bases their reasoning for their behavior on their certain situation or circumstance. The observers however will look at their behavior as a result of their character or who they are.

Example: Tom(actor) was late to work and said it due to traffic. His boss(observer), attributes his tardiness to irresponsibility.

Optimal arousal theory

states that optimal performance requires optimal arousal and that arousal levels that are too high or too low will impede performance. This implies that the negative stereotype will cause poor performance by increasing arousal levels beyond the optimal level

Sympathetic arousal:

SA refers to the sympathetic NS that controls your flight or fight response that is activated in stressful, life or death situations. So, experiences like pain and anxiety inducing experiences will increase the degree of sympathetic arousal, less so brain scans

Median

the median divides a series of numbers in half in numerical order. That means if the median is 25, then half of the numbers will be greater than 25 and the other half will be less

Behaviorists: what are their beliefs about behavior

Their core beliefs surround the idea that behavior is learned via observable experiences and environment factors that offer lessons and values that people later apply later in life. This specific approach doesn’t involve the effect of brain development on behavior or the psychoanalytical theories that superego, id, and ego fall under, that’s psychoanalytics

Erikson’s theory of psychosocial development

Chunking vs priming

When a person combines information into a single unit to remember it easier is chunking

When one stimulus influences how a person’s responds to a later stimulus without their conscious awareness is priming.

Atkinson-Shiffrin multi memory model

3 stages that describe how information passes in the brain in terms of memory:

1. Sensory memory: briefly holds large amounts of sensory information for a few seconds

2. Short term memory: information that receives attention will be temporarily stored and processed. Lasts for about 15-30 seconds with no rehearsal

3. Long term memory: Via rehearsal, information is stored for extended periods, potentially a lifetime. If needed, the information is brought back to short term memory

Mnemonic: See→ Store→ Last

Procedural memory

a variety of implicit memory, refers to memoryfor performing particular actions (i.e., what many people call "muscle memory").

Explicit memory

refers to information retrieval as demonstrated by a direct memory task, such as a free recall, serial recall, yes-no recognition, or forced-choice recognition task.

Semantic memory

refers to memory for general world knowledge and other meaningful information, including the meanings of words and phrases.

Episodic memory

refers to long-term memory representations of events experienced by the participant.

Which term refers to closed status positions that hinder social mobility? Distinguish this from class systems and economic systems

Caste systems are generally closed stratification systems that do not provide many opportunities for social mobility. It is a rigid social hierarchy where a person’s status is determined at birth. Not to be confused with a class system which is a way society groups people based on their social and economic status. An economic system describes how a country organizes the production, distribution, and consumption of goods, while the financial system is the network that allows money to flow through the economy

Notes from the CARS sections

Comprehension questions will often ask about the author’s primary purpose. Key words to help you identify components like the thesis, main ideas, or examples include: importantly, “the only thing that matters is”, or “for example”. Words to help identify minor points include: “by the way” or “in a few cases”. And words like: “in addition to”, “therefore”, or “consequently” help determine the author’s argument. 

Its important to understand the 2 different types of passage that you may come across: point counterpoint and compare vs contrast. Point counterpoint passages will discuss between 2 ppl while compare vs contrast will discuss commonalities and then differences. Words that signal these type of texts are on the other hand, in contrast to, “but”, or “however”. Another passage is cause and effect and signal words include “because” or “due to”. If asked about specific phrases, notice how the passage is organized and where the phrase is. Another passage type is rhetorical and these will include words like “however” or “on the other hand” but also may include repetition(metaphors, allegory, symbolism & parallelism. 

Reasoning within the text is another category question of CARS. You examine the argument made by the author by examining claims, conclusions or pieces of evidence. Structural questions ask you recognize the claims that support the author’s claim and evaluative questions criticize and consider flaws in author’s argument or evidence.