Saving for Medical School

If there was one thing I wish to start doing earlier, it would be to save efficiently for medical school.

I had been saving for quite a few years, but only recently did I discover Acorns. This investment app has helped me save much more efficiently, yet the work it takes is like nothing. "Too good to be true" was what I thought at first, but I did my research and decided to give it a try. What I love is that Acorns has a code which gives you $5 to invest in your future right away. This is helpful for someone who is interested but still unsure. Acorns also works with companies that will invest in your future if you ever buy from them. Some of these companies are: eBay, Lyft, Uber, Forever 21, Sephora, Nike, TOMS, Airbnb, etc. So much to gain and nothing to lose, isn't it?

"How does it work?" you might ask. So after downloading the app, all I had to do was selecting how much and for how long I would like to invest, as well as how "aggressive" or "conservative" I am as an investor. I selected "aggressive" just to reap the most fruits of my labor. Then, my investment was distributed to different stocks and started working for me.

After just a month, my investment has gained over $7, which would have been $0 had it sit in my bank account. I could only imagine the gain after a year or several years from now, and remember that I did not have to do a thing! This simple tool shows me everyday the power of delayed gratification, an ability that I found helpful to become real-world professional. Not only that, Acorns will definitely help me save efficiently for medical school.

I hope you find Acorns and the code for $5 helpful. Regardless, start investing in your future today, because the little things do add up. Tomorrow, you will thank yourself! As always, I am here if you have any questions. Cheers to the new year and I hope your resolutions kick off :)

Supporting Pediatric Patients

          

          This is where I came from, a developing country with limited access to healthcare. I was fortunate enough to be born in a big city where this prestigious hospital was within driving distance. But these people that you see in the picture were not as fortunate. I remember seeing many of them sleeping (or maybe waiting in exhaustion) in front of the hospital's closed gate after having to travel far and wide from their homes in the countryside. They got here in the pit of dawn just to be the first to get in once the gate opened, for the wait once inside was forever that they might not be able to catch the last ride home.

          I remember how much of a burden my medical bill was on my family. I also remember how hard it was for us to find blood donors, since we had to give in the same amount of blood as taken out of the bank for my surgery. We had to ask for help from relatives and friends because the hospital could not offer any assistance or link us to any source that could. I remember the stress that was put on my mom and dad, who still managed to tell me with a smile everyday that everything was going to be okay. 

          My little self back then did not know how much it hurt, but I am sure my future self will remember how much it hurts now while I am writing this. My tears keep dropping...

          And this is why I joined Triton Dance Marathon. So that the local hospital I support will have the funds needed to help struggling families, to ensure not only the children but also their families that everything will truly be okay. 

          I hope you could join me in this fundraising effort, and please send me your address at quynh.alyse@gmail.com so that I could personally thank you with a hand-written letter. Please also share with me your stories and let me know if it is okay for me to share yours on my fundraising page.

          All contributions will benefit Rady Children's Hospital in San Diego. Any contribution will help, and all donations are tax-deductible. Donating online is also safe and easy, as you could do so by clicking the "support me" button on my fundraising page.

          Thank you for reading my story and for visiting my page if you already did or if you are planning to. I hope to earn your support not only online but also at the event, not only in finance but also in spirit! :)

#ForTheKids,

Alyse

My fundraising page: https://Events.DanceMarathon.com/Participant/AlyseTran
Join my team: https://events.dancemarathon.com/team/TeamHappyFeet

Practice with a Purpose

Each exercise you complete will help Kaplan meet their goal of providing up to 100 scholarships to the Boys and Girls Club of America.

Deadline: March 31st
Goal: $125,000
Available tests: GRE, GMAT, LSAT, MCAT, DAT, OAT, PCAT

Practice now and start giving back by clicking here! :)

(Special thanks to Adele Savage for sharing with me this opportunity)

Human Immune Response Phases

The human immune response to an invading pathogen can consist of one, two, or three

phases, depending upon the severity of the infection. 

PHASE 1: The immediate innate immune response begins as soon as a pathogen invades.

This is sufficient to terminate most infections.

PHASE 2: If after 4 hours of infection, the action of the immediate innate immune response has not been sufficient to subdue the infection, the induced innate immune response is brought into play.

PHASE 3: If after 4 days of infection, the combined actions of the immediate and induced innate immune responses have not been sufficient to subdue the infection, the immune system commits to make an adaptive immune response. 

This response, which is made-to-order specificially for the infection at hand, is more powerful than the forces of innate immunity alone, and efficiently terminates almost all infections that get to this third phase. It is also more damaging to the tissues in which it is working. 

If adaptive immunity fails to suppress the pathogen, the infected human host will either: 

- Die of the acute infection, as frequently occurs for Ebola virus infections; or 

- Develop chronic infection, as occurs with human immunodeficiency virus (HIV), associated with debilitating disease and premature death

Special thanks to Dr. Ananda Goldrath for sharing this video!

MCAT · Biology 1 · Chapter 1 · Section 1.7

Chapter 1: Biological Molecules and Enzymes

Section 1.7: Minerals

STUDY

Question 1:
Minerals are the dissolved _____ (organic or inorganic) ions inside and outside the cell. By creating _____ across membranes, they assist in the transport of substances entering and exiting the cell. They can combine and solidify to strengthen a matrix; an example for this is _____ in bone. They can also act as cofactors to assisti enzyme and protein function; an example for this is _____ in heme, the prosthetic (AKA _____) group of _____.
→ Inorganic
    Electrochemical gradients
    Hydroxyapatite
    Iron
    Non-proteinaceous
    Cytochromes

Question 2:
Name 9 levels of organization in an organism, from lowest to highest.
→ Atoms
    Molecule
    Macromolecule
    Organelle
    Cell
    Tissue
    Organ
    Organ system
    Organism

PRACTICE

Question 1:
Minerals are the dissolved _____ (organic or inorganic) ions inside and outside the cell. By creating _____ across membranes, they assist in the transport of substances entering and exiting the cell. They can combine and solidify to strengthen a matrix; an example for this is _____ in bone. They can also act as cofactors to assisti enzyme and protein function; an example for this is _____ in heme, the prosthetic (AKA _____) group of _____.

Question 2:
Name 9 levels of organization in an organism, from lowest to highest.

ANSWER KEY

Question 1:
→ Inorganic
    Electrochemical gradients
    Hydroxyapatite
    Iron
    Non-proteinaceous
    Cytochromes

Question 2:
→ Atoms
    Molecule
    Macromolecule
    Organelle
    Cell
    Tissue
    Organ
    Organ system
    Organism

MCAT · Biology 1 · Chapter 1 · Section 1.6

Chapter 1: Biological Molecules and Enzymes

Section 1.6: Amino Acids and Proteins

STUDY

Question 1:

A single protein is built from a chain of _____ linked together by _____ bonds; thus, proteins are AKA _____.

→ Amino acids

    Peptide

    Polypeptides

Question 2:

Variety of structures and functions of proteins is resulted from variety of _____ of amino acids.

→ Possible combinations

Question 3:

_____ bond creates _____ functional group (which is an amine connected to a carbonyl carbon). It's formed via _____ reaction of 2 amino acids. The reverse reaction is _____ of aforementioned bond.

→ Peptide

    Amide

    Dehydration

    Hydrolysis

Question 4:

Explain how peptide bond has a partial double bond character and describe this character's function.

→ Since nitrogen is most stable with 4 bonds and oxygen attracts electron density, resulting in a

    partial negative charge, electrons delocalize to give peptide bond a partial double bond character.

    This double bond character prevents the bond from rotating freely. It also affects secondary and,

    to some extent, tertiary structure of the polypeptide.

Question 5:

There're _____ (number) common α-amino acids. They're called α-amino acids because _____. In humans, 9 of the amino acids are _____, meaning that they can't be manufactured by the body and, thus, must be ingested directly. Digested proteins reach the cells of human body as _____.

→ 20

    The amine is attached to the carbon in α position to the carbonyl

    Essential

    Single amino acids

Question 6:

Draw a general structure of amino acids and label its groups. 

→ 

(Source: http://study.com/cimages/multimages/16/amino_acid_structure.png)

Question 7:

R groups have different chemical properties, which can be divided into 4 categories: _____, _____, _____, and _____.

→ Acidic (also polar)

    Basic (also polar)

    Polar

    Non-polar

Question 8:

Generally, if R group contains carboxylic acids, then it's _____ (acidic or basic). Whereas if R group contains amines, then it's _____ (acidic or basic).

→ Acidic

    Basic

Question 9:

Acidity or basicity of R groups _____ (does or does not) affect the overall structure of the protein.

→ Does

Question 10:

Categorize 20 common α-amino acids based on their R groups' chemical properties. Provide their corresponding names, 3-letter codes, and 1-letter codes. Don't have to memorize their structures. 

→ 

(Source: http://dnangelica.com/dnangelica/wp-content/gallery/bioquimica-1/Tema01-aminoacids.jpg)

     

     GROUP 1: Non-polar, aliphatic R groups

     Glycine (Gly, G)

     Alanine (Ala, A)

     Proline (Pro, P)

     Valine (Val, V)

     Leucine (Leu, L)

     Isoleucine (Ile, I)

     Methionine (Met, M)

     GROUP 2: Polar, uncharged R groups

     Serine (Ser, S)

     Threonine (Thr, T)

     Cysteine (Cys, C)

     Asparagine (Asn, N)

     Glutamine (Gln, Q)

     GROUP 3: Aromatic R groups

     Phenylalanine (Phe, F)

     Tyrosine (Tyr, Y)

     Tryptophan (Trp, W)

     GROUP 4: Positively charged R groups

     Lysine (Lys, K)

     Arginine (Arg, R)

     Histidine (His, H)

     GROUP 5: Negatively charged R groups

     Aspartate or Aspartic Acid (Asp, D)

     Glutamate or Glutamic Acid (Glu, E)

Question 11:

The structure of a protein is described according to several levels of organization. These 4 structures are _____, _____, _____, and _____.

→ Primary structure

    Secondary structure

    Tertiary structure

    Quaternary structure

Question 12:

The _____ and _____ of amino acids in a polypeptide is called the primary structure. Once this structure is formed, the _____ (single or double) chain(s) can form into distinct shapes known as the secondary structure. This polypeptide can twist into a(n) _____, or lie alongside itself and form a(n) _____ - both of which are reinforced by _____ bonds between _____ of 1 amino acid and the _____ on another amino acid. A single protein usually contains _____ (only one structure or both structures) at various locations along its chain. These areas of secondary structure contribute to the _____, or overall shape, of the protein. The tertiary structure refers to _____ shape formed by _____ and _____ of the peptide chain. The quaternary structure is formed when 2 or more _____ bind together.

→ Number

    Sequence

    Single

    α-helix

    β-pleated sheet 

    Hydrogen

    Carbonyl oxygen 

    Hydrogen

    Both structures

    Conformation

    3 dimensional 

    Curls

    Folds

    Polypeptide chains 

Question 13:

With _____ (α-helices or β-pleated sheets), connecting segments of the 2 strands can lie in the same or opposite directions. 

→ β-pleated sheets

Question 14:

Amino acids in solution, such as in biological environment, will always carry one or more charges. The position and nature of the charges will depend upon the _____ of the solution.

→ pH

Question 15:

_____ (all or most) proteins have a primary structure and _____ (all or most) have areas of secondary structure. _____ (larger or smaller) proteins can have a tertiary and quaternary structures. 

→ All

    Most

    Larger 

Question 16:

Name 5 forces that contribute to tertiary and quaternary structures. 

→ Covalent disulfide bonds between 2 cysteine amino acids on different parts of the chain, creating

    dimer cystine (not a typo, not "dimer cysteine")

    Electrostatic (ionic) interactions, mostly between acidic and basic side chains

    Hydrogen bonds

    Van der Waals forces

    Hydrophobic side chains pushed away from water toward the protein's center (hydrophobic

    bonding)

Question 17:

In addition to the 5 forces that contribute to tertiary structure, there're turns that disrupt both α-helix and β-pleated sheet formation. These turns are induced by the amino acid _____ due to its physical structure: _____.

→ Proline

    R group binds to amine group, causing protein to be more rigid than a typical amino acid and

    creating kink in the protein's structure

Question 18:

Though many different conformations are possible for any 1 protein, it'll generally exist in 1 of a few possible conformations that have the highest _____ and allow the protein to carry out its necessary functions. 

→ Stability

Question 19:

The water surrounding proteins in biological environment helps stabilize these native conformations. Due to the presence of _____ (hydrophobic or hydrophilic) R groups on the protein, surrounding molecules assemble into an organized structure known as a _____ that forces these R groups _____ (toward or away from) the surrounding water and _____ (toward or away from)  the inner area of the protein. This action is highly _____ (favorable or unfavorable) because it _____ (increases or decreases) the size of highly ordered solvation layer, _____ (increasing or decreasing) the entropy of the system. 

→ Hydrophobic

    Solvation layer

    Away from

    Toward

    Favorable

    Decreases

    Increasing

Question 20:

When the native conformation is disrupted, the protein is said to be _____; it has lost most of its _____, _____, and _____ structures. Very often, once the denaturing agent is removed, the protein _____ (will or will no longer) be able to spontaneously refold to its original conformation. This suggests that the _____ plays a key role in the conformation of a protein. 

→ Denatured 

    Secondary

    Tertiary 

    Quaternary

    Will

    Amino acid sequence

Question 21:

The large array of possible functions of proteins is made possible by _____.

→ The large array of possible combinations of amino acids that have different physical properties 

Question 22:

Name 2 types of proteins. Which type is more abundant than the other?

→ Globular (more abundant) and structural 

Question 23:

Name 7 major functions of globular proteins and give an example for each function. 

→ Enzymes: pepsin

    Hormones: insulin

    Membrane pumps and channels: Na⁺/K⁺ pump and voltage-gated Na⁺ channels

    Membrane receptors: nicotinic receptors on a post-synaptic neuron

    Intercellular and intracellular transport and storage: hemoglobin and myoglobin

    Osmotic regulators: albumin

    Immune response: antibodies

Question 24:

Structural proteins maintain and strengthen _____ and _____ structures. _____, a structural protein made from a unique type of _____ (sheet or helix), is the _____ (most or least) abundant protein in the body. Collagen fibers _____ (strengthen or weaken) skin, tendons, ligaments, and bones, among other structures. _____, which make up flagella and cilia, are made from _____, which polymerizes under the right conditions to become a structural protein.

→ Cellular

    Matrix

    Collagen

    Helix

    Most

    Microtubules

    Globular tubulin

Question 25:

Draw a basic cell structure to illustrate the differences between cytosol (AKA cytoplasmic matrix), cytoplasm, and nucleoplasm.

→

Question 26:

Glycoproteins are proteins with _____ groups attached. Glycoproteins are a component of cellular _____. Proteoglycans are a mixture of proteins and _____, but the latter takes up more than _____%. Proteoglycans are the major component of extracellular _____. Cytochromes are proteins that require a(n) _____ group to function. Cytochromes get their name from the _____ (hint: what does chrome mean?) that they add to the cell. Examples of cytochromes are _____ and the cytochromes of the _____ in mitochondria's inner membrane. Proteins containing non-proteinaceous (= prosthetic) components are called _____ proteins.

→ Carbohydrate

    Plasma membranes

    Carbohydrates

    50

    Matrix

    Prosthetic (= non-proteinaceous) heme

    Color

    Hemoglobin

    Electron transport chain

    Conjugated

Question 27:

Denatured form of protein doesn't contain any of the _____ (α-helices or β-sheets) that the properly folded protein has. Denaturing agents rarely affect the _____ (primary, secondary, tertiary, or quaternary) structure of a protein, which contains the essential information for conformation. Thus, mildly denatured proteins often _____ (can or cannot) spontaneously return to their original conformation. 

→ α-helices

    Primary

    Can

Question 28:

Name 5 denaturing agents and which forces they disrupt.

→ Urea disrupts hydrogen bonds.

    Salt or change in pH disrupts electrostatic bonds.

    Mercaptoethanol disrupts disulfide bonds.

    Organic solvents disrupt hydrophobic forces.

    Heat disrupts all forces.

Question 29:

Cytochrome proteins carry out electron transport via oxidation and reduction of _____ group.

→ Heme

PRACTICE

Question 1:

A single protein is built from a chain of _____ linked together by _____ bonds; thus, proteins are AKA _____.

Question 2:

Variety of structures and functions of proteins is resulted from variety of _____ of amino acids.

Question 3:

_____ bond creates _____ functional group (which is an amine connected to a carbonyl carbon). It's formed via _____ reaction of 2 amino acids. The reverse reaction is _____ of aforementioned bond.

Question 4:

Explain how peptide bond has a partial double bond character and describe this character's function.

Question 5:

There're _____ (number) common α-amino acids. They're called α-amino acids because _____. In humans, 9 of the amino acids are _____, meaning that they can't be manufactured by the body and, thus, must be ingested directly. Digested proteins reach the cells of human body as _____.

Question 6:

Draw a general structure of amino acids and label its groups. 

Question 7:

R groups have different chemical properties, which can be divided into 4 categories: _____, _____, _____, and _____.

Question 8:

Generally, if R group contains carboxylic acids, then it's _____ (acidic or basic). Whereas if R group contains amines, then it's _____ (acidic or basic).

Question 9:

Acidity or basicity of R groups _____ (does or does not) affect the overall structure of the protein.

Question 10:

Categorize 20 common α-amino acids based on their R groups' chemical properties. Provide their corresponding names, 3-letter codes, and 1-letter codes. Don't have to memorize their structures. 

Question 11:

The structure of a protein is described according to several levels of organization. These 4 structures are _____, _____, _____, and _____.

Question 12:

The _____ and _____ of amino acids in a polypeptide is called the primary structure. Once this structure is formed, the _____ (single or double) chain(s) can form into distinct shapes known as the secondary structure. This polypeptide can twist into a(n) _____, or lie alongside itself and form a(n) _____ - both of which are reinforced by _____ bonds between _____ of 1 amino acid and the _____ on another amino acid. A single protein usually contains _____ (only one structure or both structures) at various locations along its chain. These areas of secondary structure contribute to the _____, or overall shape, of the protein. The tertiary structure refers to _____ shape formed by _____ and _____ of the peptide chain. The quaternary structure is formed when 2 or more _____ bind together.

Question 13:

With _____ (α-helices or β-pleated sheets), connecting segments of the 2 strands can lie in the same or opposite directions. 

Question 14:

Amino acids in solution, such as in biological environment, will always carry one or more charges. The position and nature of the charges will depend upon the _____ of the solution.

Question 15:

_____ (all or most) proteins have a primary structure and _____ (all or most) have areas of secondary structure. _____ (larger or smaller) proteins can have a tertiary and quaternary structures.  

Question 16:

Name 5 forces that contribute to tertiary and quaternary structures. 

Question 17:

In addition to the 5 forces that contribute to tertiary structure, there're turns that disrupt both α-helix and β-pleated sheet formation. These turns are induced by the amino acid _____ due to its physical structure: _____.

Question 18:

Though many different conformations are possible for any 1 protein, it'll generally exist in 1 of a few possible conformations that have the highest _____ and allow the protein to carry out its necessary functions. 

Question 19:

The water surrounding proteins in biological environment helps stabilize these native conformations. Due to the presence of _____ (hydrophobic or hydrophilic) R groups on the protein, surrounding molecules assemble into an organized structure known as a _____ that forces these R groups _____ (toward or away from) the surrounding water and _____ (toward or away from)  the inner area of the protein. This action is highly _____ (favorable or unfavorable) because it _____ (increases or decreases) the size of highly ordered solvation layer, _____ (increasing or decreasing) the entropy of the system. 

Question 20:

When the native conformation is disrupted, the protein is said to be _____; it has lost most of its _____, _____, and _____ structures. Very often, once the denaturing agent is removed, the protein _____ (will or will no longer) be able to spontaneously refold to its original conformation. This suggests that the _____ plays a key role in the conformation of a protein. 

Question 21:

The large array of possible functions of proteins is made possible by _____.

Question 22:

Name 2 types of proteins. Which type is more abundant than the other?

Question 23:

Name 7 major functions of globular proteins and give an example for each function. 

Question 24:

Structural proteins maintain and strengthen _____ and _____ structures. _____, a structural protein made from a unique type of _____ (sheet or helix), is the _____ (most or least) abundant protein in the body. Collagen fibers _____ (strengthen or weaken) skin, tendons, ligaments, and bones, among other structures. _____, which make up flagella and cilia, are made from _____, which polymerizes under the right conditions to become a structural protein.

Question 25:

Draw a basic cell structure to illustrate the differences between cytosol (AKA cytoplasmic matrix), cytoplasm, and nucleoplasm.

Question 26:

Glycoproteins are proteins with _____ groups attached. Glycoproteins are a component of cellular _____. Proteoglycans are a mixture of proteins and _____, but the latter takes up more than _____%. Proteoglycans are the major component of extracellular _____. Cytochromes are proteins that require a(n) _____ group to function. Cytochromes get their name from the _____ (hint: what does chrome mean?) that they add to the cell. Examples of cytochromes are _____ and the cytochromes of the _____ in mitochondria's inner membrane. Proteins containing non-proteinaceous (= prosthetic) components are called _____ proteins.

Question 27:

Denatured form of protein doesn't contain any of the _____ (α-helices or β-sheets) that the properly folded protein has. Denaturing agents rarely affect the _____ (primary, secondary, tertiary, or quaternary) structure of a protein, which contains the essential information for conformation. Thus, mildly denatured proteins often _____ (can or cannot) spontaneously return to their original conformation. 

Question 28:

Name 5 denaturing agents and which forces they disrupt.

Question 29:

Cytochrome proteins carry out electron transport via oxidation and reduction of _____ group.

ANSWER KEY

Question 1:

→ Amino acids

    Peptide

    Polypeptides

Question 2:

→ Possible combinations

Question 3:

→ Peptide

    Amide

    Dehydration

    Hydrolysis

Question 4:

→ Since nitrogen is most stable with 4 bonds and oxygen attracts electron density, resulting in a

    partial negative charge, electrons delocalize to give peptide bond a partial double bond character.

    This double bond character prevents the bond from rotating freely. It also affects secondary and,

    to some extent, tertiary structure of the polypeptide.

Question 5:

→ 20

    The amine is attached to the carbon in α position to the carbonyl

    Essential

    Single amino acids

Question 6:

→

(Source: http://study.com/cimages/multimages/16/amino_acid_structure.png)

Question 7:

→ Acidic (also polar)

    Basic (also polar)

    Polar

    Non-polar

Question 8:

→ Acidic

    Basic

Question 9:

→ Does

Question 10:

→

(Source: http://dnangelica.com/dnangelica/wp-content/gallery/bioquimica-1/Tema01-aminoacids.jpg)

     

     GROUP 1: Non-polar, aliphatic R groups

     Glycine (Gly, G)

     Alanine (Ala, A)

     Proline (Pro, P)

     Valine (Val, V)

     Leucine (Leu, L)

     Isoleucine (Ile, I)

     Methionine (Met, M)

     GROUP 2: Polar, uncharged R groups

     Serine (Ser, S)

     Threonine (Thr, T)

     Cysteine (Cys, C)

     Asparagine (Asn, N)

     Glutamine (Gln, Q)

     GROUP 3: Aromatic R groups

     Phenylalanine (Phe, F)

     Tyrosine (Tyr, Y)

     Tryptophan (Trp, W)

     GROUP 4: Positively charged R groups

     Lysine (Lys, K)

     Arginine (Arg, R)

     Histidine (His, H)

     GROUP 5: Negatively charged R groups

     Aspartate or Aspartic Acid (Asp, D)

     Glutamate or Glutamic Acid (Glu, E)

Question 11:

→ Primary structure

     Secondary structure

     Tertiary structure

     Quaternary structure

Question 12:

→ Number

     Sequence

     Single

     α-helix

     β-pleated sheet 

     Hydrogen

     Carbonyl oxygen 

     Hydrogen

     Both structures

     Conformation

     3 dimensional 

     Curls

     Folds

     Polypeptide chains 

Question 13:

→ β-pleated sheets

Question 14:

→ pH

Question 15:

→ All

     Most

     Larger 

Question 16:

→ Covalent disulfide bonds between 2 cysteine amino acids on different parts of the chain, creating

    dimer cystine (not a typo, not "dimer cysteine")

    Electrostatic (ionic) interactions, mostly between acidic and basic side chains

    Hydrogen bonds

    Van der Waals forces

    Hydrophobic side chains pushed away from water toward the protein's center (hydrophobic

    bonding)

Question 17:

→ Proline

    R group binds to amine group, causing protein to be more rigid than a typical amino acid and

    creating kink in the protein's structure.

Question 18:

→ Stability

Question 19:

→ Hydrophobic

    Solvation layer

    Away from

    Toward

    Favorable

    Decreases

    Increasing

Question 20:

→ Denatured 

    Secondary

    Tertiary 

    Quaternary

    Will

    Amino acid sequence

Question 21:

→ The large array of possible combinations of amino acids that have different physical properties 

Question 22:

→ Globular (more abundant) and structural 

Question 23:

→ Enzymes: pepsin

    Hormones: insulin

    Membrane pumps and channels: Na⁺/K⁺ pump and voltage-gated Na⁺ channels

    Membrane receptors: nicotinic receptors on a post-synaptic neuron

    Intercellular and intracellular transport and storage: hemoglobin and myoglobin

    Osmotic regulators: albumin

    Immune response: antibodies

Question 24:

→ Cellular

    Matrix

    Collagen

    Helix

    Most

    Microtubules

    Globular tubulin

Question 25:

→

Question 26:

→ Carbohydrate

    Plasma membranes

    Carbohydrates

    50

    Matrix

    Prosthetic (= non-proteinaceous) heme

    Color

    Hemoglobin

    Electron transport chain

    Conjugated

Question 27: 

→ α-helices

    Primary

    Can

Question 28:

→ Urea disrupts hydrogen bonds.

    Salt or change in pH disrupts electrostatic bonds.

    Mercaptoethanol disrupts disulfide bonds.

    Organic solvents disrupt hydrophobic forces.

    Heat disrupts all forces.

Question 29

→ Heme

MCAT · Biology 1 · Chapter 1 · Section 1.5

Chapter 1: Biological Molecules and Enzymes

Section 1.5: Nucleotides

STUDY

Question 1:
Nucleotides involve in the cell's use of _____ and comprising the building blocks of every organism's _____. They're composed of 3 components: _____, _____, and _____.
→ Energy
     Genetic material
     A 5-carbon (pentose) sugar
     A nitrogenous base
     A phosphate group
**Review**

(Source: http://image.slidesharecdn.com/organicchemistry-131105135539-phpapp02/95/organic-chemistry-7-638.jpg?cb=1383659789)

Question 2:
In DNA, the highly stable _____, along with the _____, are able to link together to form a stable and organized backbone.
→ Sugars
     Phosphate groups

Question 3:
Both sugars and phosphate groups are _____ (polar or non-polar) and, thus, can face _____ (outward or inward) into the watery solvent of the cell.
→ Polar
     Outward

Question 4:
Nitrogenous bases can form _____ (weak, moderate, or strong) _____ bonds with each other that stabilize the _____-stranded (single or double) structure of DNA but can also be separated to allow the replication of genetic material.
→ Weak
     Hydrogen
     Double

Question 5:
Nucleoside = _____ sugar + _____ base + _____ (number) phosphate groups
Nucleotide = _____ sugar + _____ base + _____ (number) phosphate groups
→ Pentose
     Nitrogenous
     0
     Pentose
     Nitrogenous
     1 or more

Question 6:
Nucleotides are _____ (monomers or polymers), whereas nucleic acids are _____ (monomers or polymers). _____ (nucleotides or nucleic acids) form polymers to create _____ (nucleotides or nucleic acids).
→ Monomers
     Polymers
     Nucleotides
     Nucleic acids

Question 7:
Nucleotides form polymers to create nucleic acids, _____ and _____, which allow for expression of genetic traits by specifying the production of _____ (carbohydrates, proteins, or lipids).
→ DNA (DeoxyriboNucleic Acid)
     RNA (RiboNucleic Acid)
     Proteins

Question 8:
In nucleic acids, nucleotides are joined together into long strands by _____ bonds between phosphate group of 1 nucleotide and 3rd carbon of pentose sugar of the other nucleotide, forming a _____ backbone.
→ Phosphodiester
     Sugar-phosphate

Question 9:
Nucleotides are written in the _____ (5' to 3' or 3' to 5') direction, so that the top strand runs _____ (5' to 3' or 3' to 5') and the bottom strand runs _____ (5' to 3' or 3' to 5').
→ 5' to 3'
     5' to 3'
     3' to 5'

Question 10:
Name 4 nitrogenous bases and their abbreviation in DNA. Identify which 2 are purines and which 2 are pyrimidines. Identify complementary strands  and how many H-bonds are formed between them, with " = " means 2 H-bonds and " ≡ " means 3 H-bonds.
→ Adenine (A) = Thymine (T)
     Guanine (G) ≡ Cytosine (C)
**Mnemonic**
Pyrimidine: cytosine and thymine
 
Question 11:
Purine is a _____-ringed (number) structure, whereas pyrimidine is a _____-ringed (number) structure.
→ 2
     1

Question 12:
DNA usually exists in double-stranded structure described by the _____ model, named after 2 scientists who are credited with 1st theorizing DNA structure.
→ Watson-Crick
**Self-notes**
Special thanks to Rosalind Franklin, an unsung hero

(Source: https://askabiologist.asu.edu/sites/default/files/resources/articles/crystal_clear/Rosalind_Franklin_Plate_1_DNA_B_form_1000.jpg)

Question 13:
In double-stranded structure, AKA the B form, the 2 strands run side-by-side in opposite _____ (5' to 3' or 3' to 5') direction (thus, anti-parallel) bound together by _____ bonds between nitrogenous bases. This bonding is often referred to as _____. The length of DNA strands is measured in _____.
→ 3' to 5'
     Hydrogen
     Base-pairing
     Base-pair (bp)

Question 14:
2 strands that match up in the correct order with each other are called _____ strands. When they bind together, they curl into a _____ which contains 2 distinct grooves called the _____ and the _____. Each groove spirals _____ (once or twice) around the structure for every _____ (number) base-pairs. This DNA structure is _____ (stable or unstable) in the cellular environment and allows for replication of genetic material.
→ Complementary
     Double helix
     Major groove
     Minor groove
     Once
     10
     Stable

(Source: http://www.biologynoteshelp.com/wp-content/uploads/2016/06/MAJOR-AND-MINOR-GROOVES-210x300.jpg)

(Source: https://classconnection.s3.amazonaws.com/251/flashcards/704251/png/grooves1316409303998.png)

Question 15:
DNA (which stands for _____) is a polymer of _____, each of which is composed of 3 parts: _____, _____, and _____. Purines are _____ and _____, whereas pyrimidines are _____ and _____.
→ DeoxyriboNucleic Acid
     Nucleotides
     Phosphate group
     5-carbon (pentose) sugar

Question 16:
_____, a nitrogenous base in RNA that is complementary to Adenine, is a _____ (purine or pyrimidine).
→ Uracil
     Pyrimidine

Question 17:
2 _____ (phosphodiester bonds or H-bonds) hold Adenine and Thymine together, whereas 3 _____ (phosphodiester bonds or H-bonds) hold Guanine and Cytosine together. This means that more energy is required to separate _____ (Adenine = Thymine bond or Guanine ≡ Cytosine bond).
→ H-bonds
     H-bonds
     Guanine ≡ Cytosine bond

Question 18:
RNA (which stands for _____) is identical to DNA (which stands for _____) in structure except that:
1. Carbon #_____ on pentose sugar is not _____, meaning that it has a _____ group attached;
2. RNA is almost always _____-stranded (single or double); and
3. RNA contains the pyrimidine _____ instead of _____, both of which are complementary to _____.
→ RiboNucleic Acid
     DeoxyriboNucleic Acid
     2
     Deoxygenated
     Hydroxyl
     Single
     Uracil (U)
     Thymine (T)
     Adenine (A)

Question 19:
Unlike DNA, RNA _____ (can or cannot) move through the nuclear pores and _____ (is or is not) confined to the nucleus.
→ Can
     Is not

Question 20:
3 important types of RNA are _____ (which stands for _____), _____ (which stands for _____), and _____ (which stands for _____).
→ mRNA
     Messenger RNA
     rRNA
     Ribosomal RNA
     tRNA
     Transfer RNA

Question 21:
A common cause of mutations in DNA is the similarity in structure between uracil and thymine. Draw their structures and circle what differentiates one from the other.
→ 

(Source: https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEj6od2aRe-5rGq2YDGsfjX642n1x_hdfABgk2nDtl07__kVwKU-TM5wkRiBUCAV2lUEqEKWrmte38eeKQYo3Woley4fFeqtkddfd4BR-Fr7bAchEmbtgVImVZZKF9PGhouWQLueQG-4Xp8b/s1600/uracil-thymine.png)

Question 22:
Draw the structures of Adenine, Thymine, Guanine, and Cytosine. Demonstrate which ones pair together and how they pair.
→ 

(Source: https://biochemistry3rst.files.wordpress.com/2014/04/hydrogen-bonds.gif)

Question 23:
In addition to forming genetic material, nucleotides also serve other purposes in the cell. Name 4 other important nucleotides and briefly describe their purposes.
→ ATP (= Adenosine TriPhosphate): main source of readily available energy for the cell
     cAMP (= cyclic AMP): important component in many second messenger systems
     NADH and FADH₂: co-enzymes involved in Krebs cycle

PRACTICE

Question 1:
Nucleotides involve in the cell's use of _____ and comprising the building blocks of every organism's _____. They're composed of 3 components: _____, _____, and _____.

Question 2:
In DNA, the highly stable _____, along with the _____, are able to link together to form a stable and organized backbone.

Question 3:
Both sugars and phosphate groups are _____ (polar or non-polar) and, thus, can face _____ (outward or inward) into the watery solvent of the cell.

Question 4:
Nitrogenous bases can form _____ (weak, moderate, or strong) _____ bonds with each other that stabilize the _____-stranded (single or double) structure of DNA but can also be separated to allow the replication of genetic material.

Question 5:
Nucleoside = _____ sugar + _____ base + _____ (number) phosphate groups
Nucleotide = _____ sugar + _____ base + _____ (number) phosphate groups

Question 6:
Nucleotides are _____ (monomers or polymers), whereas nucleic acids are _____ (monomers or polymers). _____ (nucleotides or nucleic acids) form polymers to create _____ (nucleotides or nucleic acids).

Question 7:
Nucleotides form polymers to create nucleic acids, _____ and _____, which allow for expression of genetic traits by specifying the production of _____ (carbohydrates, proteins, or lipids).

Question 8:
In nucleic acids, nucleotides are joined together into long strands by _____ bonds between phosphate group of 1 nucleotide and 3rd carbon of pentose sugar of the other nucleotide, forming a _____ backbone.

Question 9:
Nucleotides are written in the _____ (5' to 3' or 3' to 5') direction, so that the top strand runs _____ (5' to 3' or 3' to 5') and the bottom strand runs _____ (5' to 3' or 3' to 5').

Question 10:
Name 4 nitrogenous bases and their abbreviation in DNA. Identify which 2 are purines and which 2 are pyrimidines. Identify complementary strands  and how many H-bonds are formed between them, with " = " means 2 H-bonds and " ≡ " means 3 H-bonds.

Question 11:
Purine is a _____-ringed (number) structure, whereas pyrimidine is a _____-ringed (number) structure.

Question 12:
DNA usually exists in double-stranded structure described by the _____ model, named after 2 scientists who are credited with 1st theorizing DNA structure.

Question 13:
In double-stranded structure, AKA the B form, the 2 strands run side-by-side in opposite _____ (5' to 3' or 3' to 5') direction (thus, anti-parallel) bound together by _____ bonds between nitrogenous bases. This bonding is often referred to as _____. The length of DNA strands is measured in _____.

Question 14:
2 strands that match up in the correct order with each other are called _____ strands. When they bind together, they curl into a _____ which contains 2 distinct grooves called the _____ and the _____. Each groove spirals _____ (once or twice) around the structure for every _____ (number) base-pairs. This DNA structure is _____ (stable or unstable) in the cellular environment and allows for replication of genetic material.

Question 15:
DNA (which stands for _____) is a polymer of _____, each of which is composed of 3 parts: _____, _____, and _____. Purines are _____ and _____, whereas pyrimidines are _____ and _____.

Question 16:
_____, a nitrogenous base in RNA that is complementary to Adenine, is a _____ (purine or pyrimidine).

Question 17:
2 _____ (phosphodiester bonds or H-bonds) hold Adenine and Thymine together, whereas 3 _____ (phosphodiester bonds or H-bonds) hold Guanine and Cytosine together. This means that more energy is required to separate _____ (Adenine = Thymine bond or Guanine ≡ Cytosine bond).

Question 18:
RNA (which stands for _____) is identical to DNA (which stands for _____) in structure except that:
1. Carbon number _____ on pentose sugar is not _____, meaning that it has a _____ group attached;
2. RNA is almost always _____-stranded (single or double); and
3. RNA contains the pyrimidine _____ instead of _____, both of which are complementary to _____.

Question 19:
Unlike DNA, RNA _____ (can or cannot) move through the nuclear pores and _____ (is or is not) confined to the nucleus.

Question 20:
3 important types of RNA are _____ (which stands for _____), _____ (which stands for _____), and _____ (which stands for _____).

Question 21:
A common cause of mutations in DNA is the similarity in structure between uracil and thymine. Draw their structures and circle what differentiates one from the other.

Question 22:
Draw the structures of Adenine, Thymine, Guanine, and Cytosine. Demonstrate which ones pair together and how they pair.

Question 23:
In addition to forming genetic material, nucleotides also serve other purposes in the cell. Name 4 other important nucleotides and briefly describe their purposes.

ANSWER KEY

Question 1:
→ Energy
     Genetic material
     A 5-carbon (pentose) sugar
     A nitrogenous base
     A phosphate group
**Review**

(Source: http://image.slidesharecdn.com/organicchemistry-131105135539-phpapp02/95/organic-chemistry-7-638.jpg?cb=1383659789)

Question 2:
→ Sugars
     Phosphate groups

Question 3:
→ Polar
     Outward

Question 4:
→ Weak
     Hydrogen
     Double

Question 5:
→ Pentose
     Nitrogenous
     0
     Pentose
     Nitrogenous
     1 or more

Question 6:
→ Monomers
     Polymers
     Nucleotides
     Nucleic acids

Question 7:
→ DNA (DeoxyriboNucleic Acid)
     RNA (RiboNucleic Acid)
     Proteins

Question 8:
→ Phosphodiester
     Sugar-phosphate

Question 9:
→ 5' to 3'
     5' to 3'
     3' to 5'

Question 10:
→ Adenine (A) = Thymine (T)
     Guanine (G) ≡ Cytosine (C)
**Mnemonic**
Pyrimidine: cytosine and thymine

Question 11:
→ 2
     1
Question 12:
→ Watson-Crick

Question 13:
→ 3' to 5'
     Hydrogen
     Base-pairing
     Base-pair (bp)

Question 14:
→ Complementary
     Double helix
     Major groove
     Minor groove
     Once
     10
     Stable

(Source: http://www.biologynoteshelp.com/wp-content/uploads/2016/06/MAJOR-AND-MINOR-GROOVES-210x300.jpg)

(Source: https://classconnection.s3.amazonaws.com/251/flashcards/704251/png/grooves1316409303998.png)

Question 15:
→ DeoxyriboNucleic Acid
     Nucleotides
     Phosphate group
     5-carbon (pentose) sugar

Question 16:
→ Uracil
     Pyrimidine

Question 17:
→ H-bonds
     H-bonds
     Guanine ≡ Cytosine bond

Question 18:
→ RiboNucleic Acid
     DeoxyriboNucleic Acid
     2
     Deoxygenated
     Hydroxyl
     Single
     Uracil (U)
     Thymine (T)
     Adenine (A)

Question 19:
→ Can
     Is not

Question 20:
→ mRNA
     Messenger RNA
     rRNA
     Ribosomal RNA
     tRNA
     Transfer RNA

Question 21:
→ 

(Source: https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEj6od2aRe-5rGq2YDGsfjX642n1x_hdfABgk2nDtl07__kVwKU-TM5wkRiBUCAV2lUEqEKWrmte38eeKQYo3Woley4fFeqtkddfd4BR-Fr7bAchEmbtgVImVZZKF9PGhouWQLueQG-4Xp8b/s1600/uracil-thymine.png)

Question 22:
→ 

(Source: https://biochemistry3rst.files.wordpress.com/2014/04/hydrogen-bonds.gif)

Question 23:
→ ATP (= Adenosine TriPhosphate): main source of readily available energy for the cell
     cAMP (= cyclic AMP): important component in many second messenger systems
     NADH and FADH₂: co-enzymes involved in Krebs cycle