Exam 1 Flashcards by Eva Calderon

What is a fact?

An observation

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What is a law?

A description of a behavior that does not explain why it behaves this way

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What is a theory?

A well-sustained explanation of facts that explains how something happens, used to make predictions

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What is a hypothesis?

A uncertain question that can be tested with experiments

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What is an atom?

The smallest part of a substance that cannot be broken down chemically (made up of protons, neutrons and electrons)

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What is a proton?

Large, positively charged particle

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What is a neutron?

A Large mass with no charge, alters the stability/radioactivity of an atom

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What is an electron?

Smallest particle mass, negative charge

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How do you calculate atomic mass?

Protons + neutrons

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How do you calculate the charge on an atom?

Protons + electrons

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What is an isotope?

The forms of elements that have the same # of protons but a different number of neutrons

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At some point in their life cycle, all cells have a _____, whereas not all cells have a(n) _____.

plasma membrane; RNA or DNA

nucleus; plasma membrane

nucleus; nuclear membrane

nucleus; cytoplasm

plasma membrane; nuclear membrane

Plasma membrane, nuclear membrane

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A boy observes a robin outside of his window. He notices the robin repeatedly cocks its head to one side before pecking the ground. The boy suspects that when the robin cocks its head it is actually listening for worms or insects underground. If the boy notes that a single robin routinely catches a worm after cocking its head, would this observation prove his hypothesis to be correct?

Question options:

No, as this would prove the boy’s hypothesis is incorrect.

Yes, and no further experiments are needed.

Yes, but further experiments are needed.

No, this observation would only support the boy’s hypothesis, but not prove it.

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Imagine that a scientist is able to isolate a single, intact nerve cell from a human cadaver. How large could this cell be?

Question options:

a thousand microns

a hundred microns

ten microns

a meter

a single micron

A meter

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In which of the domains do the cells store their genetic information in a nucleus?

Question options:

Archaea

Archaea and Bacteria

Eukarya and Archaea

Eukarya

Bacteria and Eukarya

Eukarya

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In Pasteur’s experiment showing that living organisms arise from other living organisms, which one of the following statements MOST accurately describes Pasteur’s hypothesis? (See text book.)

Question options:

Straight-neck flasks allow for more contamination than swan-neck flasks.

Sterilization of broth kills microbes.

Microbes should be capable of growing equally well in sterile broth contained in both straight-neck and swan-neck flasks.

If microbes arise from nonliving matter, they should appear spontaneously in sterile broth.

The first cells must have come from chemical reactions occurring in early Earth.

If microbes arise from nonliving matter, they should appear spontaneously in sterile broth.

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A major difference between eukaryotic cells and prokaryotic cells is that:

Question options:

prokaryotic cells have a nucleus and eukaryotic cells do not.

both eukaryotic cells and prokaryotic cells have a nucleus.

eukaryotic cells have a nucleus and prokaryotic cells do not.

neither eukaryotic cells nor prokaryotic cells have a nucleus.

eukaryotic cells have a nucleus and prokaryotic cells do not.

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The most common isotope of oxygen has zero net charge, 8 protons and an atomic mass of 16. How many electrons are present in the orbitals around an atom of oxygen?

Question options:

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The language of nucleic acids is converted to the language of amino acids during the process known as :

Hint: See textbook for more detail about the central dogma.

Question options:

replication

translation.

central dogma.

transcription.

Translation

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Which option does not possess the ability to synthesize proteins?

Question options:

an isolated virus

a bacterial cell

a human cell

a viral particle that has infected a bacterial cell

An isolated virus

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Which of the following CORRECTLY pairs the particles of an atom with their physical properties?

Question options:

proton–uncharged; neutron–negatively charged; electron–positively charged

proton–negatively charged; neutron–uncharged; electron–positively charged

proton–positively charged; neutron–negatively charged; electron–uncharged

proton–positively charged; neutron–uncharged; electron–negatively charged

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Which of the following is NOT a key feature of individual cells:

Question options:

the presence of a plasma membrane.

the ability to harvest and transform energy from the environment.

the ability to store and transit information using nucleic acids.

the presence of a nucleus.

Presence of a nucleus

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All organisms use which of the following molecules to carry out cellular work such as growth and moving

Question options:

ATP

DNA

none of the answer choices is correct

RNA

membranes

ATP

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Which one of the following represents the flow of information as described by the central dogma of molecular biology?

Hint: See textbook for more detail about the central dogma.

Question options:

Information in RNA is transcribed into DNA and then translated into protein.

Information in DNA is directly translated into protein.

Information in protein is translated into RNA and then stored as DNA.

Information in DNA is transcribed into RNA and then translated into protein.

Information in DNA is translated into RNA and then transcribed into protein.

Information in DNA is transcribed into RNA and then translated into protein.

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The designation of a magnesium ion as Mg+2 indicates an atom that has: Question options: two more protons than neutrons. gained two protons and is positively charged. gained two protons and is negatively charged. lost two electrons and is negatively charged. lost two electrons and is positively charged.

lost two electrons and is positively charged.

The most common isotope of oxygen has 8 protons and an atomic mass of 16. How many neutrons are present in the oxygen nucleus? Question options: 4 2 6 10 8

The first cells were: Question options: viruses. eukaryotes. multicellular forms. None of the other answer options is correct. prokaryotes.

prokaryotes

One of your friends is arguing that viruses are "alive." What information would you provide to convince him that viruses are not considered alive, according to most biologists? Question options: Viruses typically have protein coats, which are distinct from plasma membrane. Viruses are much more closely related to archaeons compared to bacteria. Viruses always contain either RNA or DNA. Viruses need other types of cells to carry out metabolic reactions.

Viruses need other types of cells to carry out metabolic reactions.

Which one of the following does NOT possess the ability to synthesize its own proteins? Question options: a bacterial cell a virus a human cell

virus

What differentiates isotopes of the same element? Question options: charge electrons neutrons protons

neutrons

A mutation in _____ results in a change in _____ that sometimes produces a(n) _____ with altered structure and function. Hint: See textbook for more detail about genetic variation and mutations. Question options: protein; RNA; DNA RNA; protein; DNA protein; DNA; RNA RNA; DNA; protein DNA; RNA; protein

DNA; RNA; protein

Which one of the following pairs would be classified as isotopes of each other? Question options: 12C and 13C H and H+ C and Si Na+ and Cl–

12C and 13C

Carbon-14 (also written as 14C) is an isotope of carbon that possesses: Question options: 6 protons, 2 neutrons, and 6 electrons. 6 protons, 8 neutrons, and 2 electrons. 6 protons, 6 neutrons, and 2 electrons. 8 protons, 6 neutrons, and 2 electrons. 6 protons, 8 neutrons, and 6 electrons.

6 protons, 8 neutrons, and 6 electrons.

MOST of life's diversity is: Question options: acellular. aerobic. terrestrial. aquatic. microbial.

microbial

pH equation

pH = -log([H+])

1 molar

1 M = 1mole/liter

1 millimolar

1mM = 1 x 10^ -3

1 micromolar

1uM = 1 x 10^ -6

1 nanomolar

1nM = 1 x 10^ -9

What is an isotope?

Different species of the same element, same atomic number but different amount of neutrons in the nucleus

How many electrons go in each of the first three shells?

2, 4, 4

How are covalent bonds formed?

when two atoms share electrons between them

Strongest and weakest bonds

Strongest: Ionic Weakest: H-Bonds or Van Der Waals forces

What do joules and calories measure?

Energy

What is cohesion?

The tendency of molecules of the same substance to stick together, primarily due to intermolecular forces like hydrogen bonds (h2o to h2o)

What effects does cohesion have on the behavior of water

Surface tension, hydrophobic exclusion, high heat of vaporization

What is adhesion and how does that allow water to behave?

Waters attraction to other molecules, allows water to dissolve things, make things wet, and capillary action

How do h-bonds form

Forces caused by the attraction of partial opposite charges caused by electronegativity. Need to have a partially positive charged H.

How do ions form?

When a neutral atom gains or loses an electron

Why do low and high pHs disrupt the structure of organic molecules like proteins?

Ionic bonds are what hold proteins together and pH affects those: At low pH, excess H+ neutralizes O- (carboxyl), At high pH, low H+ neutralizes NH3+ (amino)

If the pH of a solution is 7, what is the concentration of protons in water? Question options: 0.1 µM 0.1 mM 0.1 M 0.1 nM

0.1 µM

Because of hydrogen bonding, water is uniquely suited for its central role in life. Many hydrophilic molecules interact freely with water, but a number of hydrophobic molecules are important for life, too. How does the interaction between water and hydrophobic molecules help to organize biological systems? Question options: None of the other answer options is correct. The ionic bonds between water molecules cause hydrophobic molecules to associate with each other and not with water molecules. Because cells are not pure water—in that they have many substances dissolved within them—the hydrophilic/hydrophobic effect has a limited role in biological organization. Because water molecules preferentially associate with each other, they force hydrophobic molecules to associate with each other and not with water molecules.

Because water molecules preferentially associate with each other, they force hydrophobic molecules to associate with each other and not with water molecules.

Which bonds rely on the attraction of full or partial positive and negative charges? Select all that apply. Question options: covalent bonds hydrogen bonds ionic bonds

hydrogen bonds ionic bonds

A pair of atoms joined by a polar covalent bond: Question options: mixes well with non-polar solvents. is unlikely to form hydrogen bonds with water. has the charge spread evenly across both atoms. has a slight positive charge on one atom and a slight negative charge on the other.

has a slight positive charge on one atom and a slight negative charge on the other.

Which number represents the pH of a solution with the highest concentration of hydrogen ions? Question options: 7.0 1.0 4.5 9.1 11.5

1.0

If proton concentration equals 1 micromolar (1 µM), what is the pH? Question options: pH 6 pH -6 pH 9 pH -9

pH 6

What type of bond forms between the oxygen and hydrogens in a single molecule of water? Question options: van der Waals interactions ionic polar covalent hydrogen

polar covalent

The ability of atoms to attract electrons is referred to as: Question options: hydrophobicity. cohesion. van der Waals attraction. potential energy. electronegativity.

electronegativity.

If proton concentration equals 1 millimolar (1 mM), what is the pH? Question options: pH 1 pH -1 pH 3 pH -3

pH 3

The unique properties of water are due to the _____ of water molecules and the ability of water to form _____ with other water molecules and with other polar molecules. Question options: polarity; polar covalent bonds hydrophobicity; hydrogen bonds electronegativity; polar covalent bonds polarity; hydrogen bonds

polarity; hydrogen bonds

Which functional group typically has a negative charge at the pH of the cell? Question options: phosphate sulfhydryl amino methyl

phosphate

Recalling that a carbon atom possesses four valence electrons, what is the most likely structural formula for carbon dioxide (CO2)? Hint: Recall the number of covalent bonds an atom forms is typically equal to the number of empty valence slots. Question options: O=C-O O=C=O O-C-O O-C=O

O=C=O

A young girl is staring at the raindrops running down her window. She notices that the raindrops remain more or less intact, even as they cascade down the windowpane. This is a result of: Question options: hydrogen bonds between water molecules. ionic bonds between water molecules. oxygen bonds between water molecules. covalent bonds between water molecules. polar covalent bonds between water molecules.

hydrogen bonds between water molecules.

Water readily dissolves compounds that are referred to as _____. (Hint: See text book.) Question options: nonpolar solvent hydrophilic hydrophobic aqueous

hydrophilic

If the pH of a solution is 2, what is the concentration of protons? Question options: 1x10^4M 1x10^-2M 1x10^2M 1x10^-4M

1x10^-2M

A pair of shared valence electrons is referred to as a(n): Question options: van der Waals interaction. hydrogen bond. ionic bond. covalent bond. hydrophobic effect.

covalent bond.

Which functional group contains only nonpolar covalent bonds? Question options: amino methyl carboxyl phosphate

methyl

If the pH of a solution is 7, what is the concentration of protons in water? Question options: 1x10^7M 1x10^-7M 1x10^9M 1x10^-9M

1x10^-7M

Water molecules have high cohesion. This is because between water molecules there are Question options: Covalent bonds. Hydrogen bonds. Hydrophilic compounds holding water together. Ionic bonds.

Hydrogen bonds.

What is required for ionic bond interactions to form? Question options: Unevenly shared electrons Opposite full charges Evenly shared electrons Opposite partial charges

Opposite full charges

Of the given types of bonds between atoms, which is the strongest? Question options: hydrogen bond ionic bond covalent bond van der Waals forces

covalent bond

In aqueous solutions, which type of bond or force has similar bond strength as ionic bond interactions? Question options: Polar covalent bond Hydrogen bonds Nonpolar covalent bond

Hydrogen bonds

Which are the strongest bonds in an aqueous environment (surrounded by water) as found in biological systems? Question options: London Dispersion Forces. Covalent bonds. Hydrogen bonds. Ionic bonds.

Covalent bonds.

Which choice is an example of a hydrogen bond? The bond that forms between: Question options: two hydrogen atoms within the same water molecule. a hydrogen atom in one water molecule and an oxygen atom in another water molecule. two oxygen atoms within different water molecules. a hydrogen and oxygen atom within the same water molecule. two hydrogen atoms within different water molecules.

a hydrogen atom in one water molecule and an oxygen atom in another water molecule.

A woman's doctor tells her to gargle with salt water. She stirs a tablespoon of salt into a cup of warm water and watches the salt dissolve. Why does the salt dissolve in water? Question options: The partial negative charges on chlorine atoms are attracted to positive charges on hydrogen atoms in water molecules. The partial positive charges on hydrogen atoms in water molecules are attracted to sodium ions. The partial positive charges on hydrogen atoms in water molecules are attracted to sodium ions, and the partial negative charges on oxygen atoms in water molecules are attracted to chlorine ions. The partial positive charges on hydrogen atoms in water molecules are attracted to chlorine ions, and the partial negative charges on oxygen atoms in water molecules are attracted to sodium ions. The partial negative charges on oxygen atoms in water molecules are attracted to chlorine ions.

The partial positive charges on hydrogen atoms in water molecules are attracted to chlorine ions, and the partial negative charges on oxygen atoms in water molecules are attracted to sodium ions.

Fill in the blanks: Polar covalent bonds allow ______ substances to interact with water. Question options: hydrophobic hydroneutral hydrophilic hydrophobic and hydrophilic

hydrophilic

Which atom is the most electronegative: (Hint see the color coded table in the lecture.) Question options: Oxygen Hydrogen Nitrogen Carbon

Oxygen

Which statement accurately describes a polar covalent bond? (Note: for the 'incorrect answers' you should know the type of bond that is described.) Question options: the interaction of a hydrogen atom connected to an atom with a high electronegativity and an electronegative atom of another molecule the unequal sharing of electrons between an atom with a partial positive charge and an atom with a partial negative charge the equal sharing of electrons between atoms of identical or similar electronegativities. None of the other answer options is correct. the interaction of an atom with very high electronegativity and an atom with very low electronegativity

the unequal sharing of electrons between an atom with a partial positive charge and an atom with a partial negative charge

What element makes up most of the dry mass of a cell?

Carbon

—OH

Hydroxyl Polar

C=O

Carbonyl Polar

—COOH

Carboxyl Polar Charged

— NH2

Amino Polar Charged

−SH

Sulfahydryl Polar

−PO4

Phosphate Polar Charged

−CH3

Menthyl Nonpolar

Why is ethanol soluble in water?

Because it can form hydrogen bonds with the h2o

How does DNA differ from RNA?

DNA sugar group is deoxyribose while RNA has ribose (RNA has an additional hydroxyl group)

What is the name of the bond that holds amino acids together?

Peptide bonds

Which functional groups are found at the beginning and end of a protein?

N - terminus starts the protein and has Amino Acids and the C - terminus has Carboxyl groups that end them off

Does polarity mean hydrophobic or hydrophilic?

polar = hydrophilic nonpolar = hydrophobic

What are the 4 major classes of macromolecules?

Nucleic acids Carbohydrates Proteins Lipids

Which macromolecules are polymers?

Nucleic acids, carbohydrates, and proteins

What are the monomers of nucleic acids, carbohydrates, and proteins

Nucleic acids = Nucleotides Carbohydrates = sugar Proteins = Amino acids

5 parts of amino acid monomer

The central carbon A hydrogen The amino group The carboxyl group The R group

What does lipid mean?

Soluble in nonpolar solvents

What happens during a dehydration reaction?

The molecule loses a water

Is water made or broken down in a dehydration reaction?

Water is made

What happens during hydrolysis

A water molecule is broken down

What type of bond is made in dehydration reaction involving amino acids?

Peptide bonds

3 parts of a nucleotide

Nitrogen base, 5 carbon sugar, phosphate group

How do you number the carbons in a 5-carbon sugar?

The one sticking up interacting with phosphate group is 5’, 4’, 3’ is the other one interacting with phosphate, 2’ has a hydroxyl group or just a hydrogen attached, 1’ is attached to the nitrogen base

Which three bases are pyrimidines (knowing the single letter code is fine).

Cytosine, thymine, and uracil

What two bases are purines?

Adenine and guanine

How many rings in pyrimidines vs purines?

Pyrimidines = 1 ring Purines = 2 rings

Deoxyribonucleic acid is directly involved in? (Select the one answer that applies.) Question options: biological catalysis. the storage of information. cell-to-cell communication. energy storage.

the storage of information

Which of the following is not one of the five 'official' parts of an amino acid? Question options: The carbonyl group The carboxyl group The amino group The R group

The carbonyl group

The difference between deoxyribose and ribose lies in the ______ carbon of the sugar unit. Question options: None 2' 5' 1'

What feature of non-covalent bonds makes them essential for life? Question options: The weakness of non-covalent bonds in the cellular environment allows interactions between molecules to be easily made, broken and reformed. This enables cells to react to the environment dynamically. The strength of non-covalent bonds in the cellular environment keeps atoms bound tightly together. This allows information stored in DNA to be passed from one generation to the next over eons. None of the other answers are correct. Non-covalent bonds are only found in salts. Because salts do not exist in cells, non-covalent bonds are not crucial for life.

The weakness of non-covalent bonds in the cellular environment allows interactions between molecules to be easily made, broken and reformed. This enables cells to react to the environment dynamically.

Which functional groups are found at the beginning and end of a protein? Question options: Amino group at the beginning, Amino group at the end. Carboxyl group at the beginning, Amino group at the end. Carboxyl group at the beginning, Carboxyl group at the end. Amino group at the beginning, Carboxyl group at the end.

Amino group at the beginning, Carboxyl group at the end.

What are the charges on the amino and carboxyl groups of an amino acid at pH 12? (Hints: Neutral means uncharged. Look back to Class 2 for a refresher on pH.) Question options: carboxyl negative and amino positive carboxyl negative and amino neutral carboxyl neutral and amino negative carboxyl neutral and amino postive carboxyl negative and amino positive Both are neutral carboxyl positive and amino negative

carboxyl negative and amino neutral

Why are prime symbols used in the numbering of carbons in the sugars of nucleotides? Question options: To differentiate between the atoms of sugars and nitrogenous bases None of the other answers are correct. To differentiate between each carbon To differentiate between DNA and RNA carbon atoms

To differentiate between the atoms of sugars and nitrogenous bases

Which one of the following components of an amino acid differs from one amino acid to another? Question options: The carboxyl group The amino group The hydrogen atom opposite the R group The central carbon atom The side chain (i.e., the R-group)

The side chain (i.e., the R-group)

As part of their normal function, many proteins bind to DNA briefly. Which types of bonds might be involved in these transient protein-DNA interactions? (Select all that apply.) Hint: Understanding that most bond types are easy to break and reform is critical for understanding how cells work. Question options: Hydrogen van der Waals forces (aka London dispersion forces) Covalent Ionic

Hydrogen van der Waals forces (aka London dispersion forces) Ionic

Single covalent bonds between carbon atoms: (Hint: See the textbook for more information about rotation.) Question options: are strong enough to support long chains of carbon atoms. allow free rotation of the carbon atoms around the bond. All of these choices are correct allow a molecule to twist and turn into many different arrangements

All of these choices are correct

During peptide bond formation a _______ molecule is released. Question options: oxygen none of the other answers is correct water hydrogen

water

Methyl groups are hydrophobic. Question options: True False

true

_____ are the subunits of nucleic acids, and _____ are the subunits of proteins. Question options: Amino acids; Nucleic bases Bases; polypeptides Nucleotides; Amino acids Polypeptides; Sugars Nucleoli; Amino acids

Nucleotides; Amino acids

The structural diversity of carbon-based molecules is determined by which of the following properties? Question options: All of these choices are correct The ability of those bonds to rotate freely The ability of carbon to form four covalent bonds The orientation of those bonds in the form of a tetrahedron

All of these choices are correct

Which group helps in stabilization of protein structure by forming covalent cross-links? (Hint: Recall the fried eggs example from the lecture notes) Question options: Amino Hydroxyl Sulfhydryl Carboxyl

Sulfhydryl

Which one of the following macromolecules is defined by a physical property instead of a chemical structure? Question options: Proteins Polysaccharides Lipids Monosaccharides Nucleic acids

lipids

Pyrimidine and purine bases are found in which macromolecules? Question options: Carbohydrates Nucleic acids Fatty acids Proteins

Nucleic acids

Lipids are polymers. Question options: True False

false

Peptide bonds are characteristic of which macromolecules? Question options: Proteins Fatty acids Carbohydrates Nucleic acids Lipids

proteins

A carboxyl group has a pKa of 3. At what pH does the concentration of R-CO2H equal R-CO2- ? Question options: pH 7 pH 3 pH 12 pH 9

pH 3

During a dehydration reaction, the molecules undergoing the reaction lose a water molecule and cells gain a water molecule. Question options: True False

true

Which functional group differentiates RNA and DNA? (Hint: The answer is directly linked to how RNA and DNA are named.) Question options: Hydroxyl None of the above Amino Carboxyl

Hydroxyl

What is the overall charge of the phosphate groups in ATP molecules found in cells (where the pH is approximately 7)? Question options: Neutral Positive Negative None of the above

negative

Because of hydrogen bonding, water is uniquely suited for its central role in life. Many hydrophilic molecules interact freely with water, but a number of hydrophobic molecules are important for life, too. How does the interaction between water and hydrophobic molecules help to organize biological systems? (Hint: look back at Class 2). Question options: None The ionic bonds between water molecules cause hydrophobic molecules to associate with each other and not with water molecules. Because cells are not pure water (they have many substances dissolved within them), the hydrophilic/hydrophobic effect has a limited role in biological organization. Because water molecules preferentially associate with each other, they force hydrophobic molecules to associate with each other and not with water molecules.

Because water molecules preferentially associate with each other, they force hydrophobic molecules to associate with each other and not with water molecules.

Which of the following is not a macromolecule? Question options: Proteins Amino acids Nucleic acids Carbohydrates Lipids

Amino acids

What does central dogma state?

DNA to RNA to Protein (Replication = copy of DNA from DNA, transcription= copy of RNA from DNA, Translation = protein based on RNA sequence)

What does dogma mean?

An idea for which there is no reasonable evidence

What happens during replication?

A copy of DNA is made from DNA

What happens during transcription?

A copy of RNA is made from DNA

What happens during transcription?

A copy of RNA is made from DNA

What happens during translation?

a protein is made based on RNA sequence

Where do transcription and translation occur in prokaryotes?

In the cytoplasm simultaneously

What do the letters M, D, and T stand for in nucleotides?

Nucleotide monophosphate, diphosphate, triphosphate

What is the difference between ATP and ADP?

ATP has 3 phosphates, ADP has 2 phosphates

What type of bond links nucleotides in a single strand of RNA or DNA?

Phosphodiester bonds

Do DNA strands have polarity?

Yes

Is a phosphate or hydroxy group found at the 5’ end of DNA? What is located at the 3’ end?

The phosphate is found at the 5’ end, the 3’ end has a hydroxyl group

What type of bond holds two different strands of DNA together?

Hydrogen bonds

How many hydrogen bonds hold A and T together?

How many hydrogen bonds hold G and C together?

Who was instrumental in the discovery of DNA double helix structure? (Hint: this is a deeply interesting story, which we didn't have time to cover in class. There is a well-written piece about its history at: https://www.sciencehistory.org/education/scientific-biographies/james-watson-francis-crick-maurice-wilkins-and-rosalind-franklin/ ) Question options: Franklin and Wilkins Franklin, Wilkins, Watson, and Crick Chargaff Watson and Crick

Franklin, Wilkins, Watson, and Crick

If a DNA molecule contains 30% Cytosine, how much Uracil will it contain? (Hint: You need to take your time to read this question carefully. It is about DNA, not RNA.) Question options: 30% 40% 0% 20%

Which of the following double stranded DNA molecules would maintain its double helical structure longer as temperature increases? Question options: A DNA molecule that has more guanine and cytosine nucleotides. Both DNA molecules would be equally stable under conditions of increasing temperature. A DNA molecule that has more adenine and thymine nucleotides.

A DNA molecule that has more guanine and cytosine nucleotides

What is true about the concentrations of purines and pyrimidines in DNA structure? (Hint: Think about the rules of base pairing.) Question options: The concentration of purines is the same as the concentrations of pyrimidines. The concentration of purines and pyrimidines depends on the width of the DNA double helix at a given point. DNA always has more purines than pyrimidines because purines have 2 rings, and subsequently can form more hydrogen bonds.

The concentration of purines is the same as the concentrations of pyrimidines.

A single-stranded DNA sequence may be written as: 5'-ATGC-3'. Which of the following could be written to represent the same single-stranded sequence? (Hint: Here I am asking about just a single strand of DNA. This is not a question about creating the complementary DNA strand.) Question options: 5'-CGTA-3'. 3'-ATGC-5' 3'-CGTA-5'. 3'-TACG-5'.

3'-CGTA-5'.

In a nucleotide, the phosphate is attached to the _____ carbon of the sugar, and the base is attached to the _____ carbon of the sugar. Question options: 5'; 1' 2'; 3' 5'; 3' 1'; 5' 3'; 5'

5'; 1'

Which one of the following represents a Watson-Crick base pair with the LARGEST number of hydrogen bonds? Question options: Cytosine and Thymine Adenine and Thymine Cytosine and Guanine Thymine and Guanine Adenine and Cytosine

Cytosine and Guanine

In a DNA strand, successive nucleotides are linked by: Question options: 3'-5' phosphodiester bonds Peptide bonds Base stacking Hydrogen bonds

3'-5' phosphodiester bonds

You are examining the DNA sequence below. What is the sequence and the direction on the complementary strand? 5'-GCTGA-3' Hint: Question options: 3'-GCTGA-5' 3'-CGACT-5' 5'-CGACT-3' 3'-TCAGC-5'

3'-CGACT-5'

You are examining the DNA sequence below. What is the sequence and the direction on the complementary strand? 5'-CTGAGT-3' Question options: 5'-GACTCA-3' 5'-CTGAGT-3' 5'-ACTCAG-3' 5'-TGAGTC-3'

5'-ACTCAG-3'

You are examining the DNA sequence below. What is the sequence and the direction on the complementary DNA strand? 3'-GTAC-5' Question options: 5'-CATG-3' 3'-GTAG-5' 5'-GTAC-3' 5'-CAUG-3'

5'-CATG-3'

You are examining the DNA sequence below, what is the sequence and the direction on the complementary strand? 3'-GACTCG-5' Question options: 5'-CTGAGC-3' 5'-GCTCAG-3' 5'-CGAGTC-3' 5'-GACTCG-3'

5'-CTGAGC-3'

In a deoxyribonucleotide, what chemical group is found at the 2' carbon of the sugar component? (Hint: Slow down here and look at the numbering of the sugar in your lecture notes.) Question options: A hydrogen atom One or more phosphate groups A hydroxyl group An amino group An oxygen

A hydrogen atom

Sometimes an error occurs and an adenine is paired to a cytosine. Why is this interaction less stable than an adenine-thymine or cytosine-guanine base pair? (Hint: This is a hard question and the idea was not directly covered in class. To answer it, you need to look at the structures of A and C and think about how they fit together to make a base-pair.) Question options: Because the phosphate groups of the two bases repel each other. Because an ionic bond cannot be formed between the two. Because the charges on the bases repel one another. Because the chemical groups that form hydrogen bonds are in the wrong positions.

Because the chemical groups that form hydrogen bonds are in the wrong positions.

The phosphodiester bonds in DNA break apart easily, allowing for DNA replication. Question options: True False

false

A single-stranded DNA sequence may be written as: 3'-AGGTACT-5'. Which of the following could be written to represent the same single-stranded sequence? (Hint: Here I am asking about a single strand of DNA. This is not a question about creating a complementary DNA strand. Whenever you see something underlined, pay close attention.) Question options: 5'-AGGTACT-3' 3'-TCCATGA-5' 3'-TCATGGA-5' 5'-TCCATGA-3' 5'-TCATGGA-3'

5'-TCATGGA-3'

In eukaryotes, newly synthesized proteins encoded by genes are found in the _____, while DNA is found the _____. Question options: Cytoplasm; Nucleus Nucleus; Nucleus also or the cytoplasm Nucleus; Cytoplasm Nucleus; Nucleus also Cytoplasm; Cytoplasm also

Cytoplasm; Nucleus

What is the sense strand?

The complementary DNA strand to the template strand, aka as non-template strand

What is the template strand?

The strand that is transcribed into RNA

Does RNA assemble in the 3’ to 5’ direction?

No, 5’ to 3’

Where is transcription initiated?

The promoter

Do promoters provide information to RNA polymerase in terms of which direction to go?

Yes

Where does transcription stop?

The terminator

Elongation

adding new nucleotides to RNA

Termination

ending the transcription process

Enhancer

Controls transcription

Promoter

Part of the gene that dictates direction of transcription

Which one of the following statements about RNA is CORRECT? (Hint: You will need to think carefully about which nucleotides are pyrimidines, which are purines, and the specific nucleotides found in DNA and RNA.) Question options: RNA uses the same pyrimidine bases as DNA. RNA has the same 5-carbon sugars as DNA. All of these choices are correct. RNA uses the same purine bases as DNA. RNA is a more stable molecule than DNA.

RNA uses the same purine bases as DNA.

Some RNA molecules possess catalytic activity. Question options: True False

true

What is the name of the enzyme complex that forms at the start of transcription? Question options: DNA gyrase RNA helicase DNA polymerase RNA polymerase

RNA polymerase

Ribose differs from deoxyribose in that a ribose: Question options: is missing a hydroxyl group. has an extra hydroxyl group. is missing a phosphate group. has an extra phosphate group.

has an extra hydroxyl group.

Transcription starts at the ________ and ends at the _________ Question options: 3' end; 5' end. promoter; 5' end. 5' cap; terminator. promoter; terminator.

promoter; terminator.

The RNA transcript runs from _____ and matches ______. (Select all that apply). Question options: the sense (i.e., non-template) DNA strand 3' to 5' the template DNA strand 5' to 3'

the sense (i.e., non-template) DNA strand 5' to 3'

During transcription, the template DNA strand and the RNA: (Select all that apply.) Question options: have an anti-parallel configuration. are bound together by covalent bonds. have a parallel configuration. are bound together by hydrogen bonds.

have an anti-parallel configuration. are bound together by hydrogen bonds.

Transcription refers to the process in cells where information from: Question options: an RNA strand is used to synthesize DNA. a protein is used to synthesize RNA. a DNA strand is used to synthesize RNA. an RNA strand is used to synthesize a protein.

a DNA strand is used to synthesize RNA.

What are the differences between peptides, poly-peptides, and proteins

A peptide is a short chain of amino acids linked together by peptide bonds, while a polypeptide is a longer chain of amino acids, and a protein is a complex molecule composed of one or more polypeptides folded into a specific shape with a biological function

4 levels protein structure

primary (1'), secondary (2'), tertiary (3'), quaternary (4')

What time of bonds are central for the primary, secondary, tertiary, and quartinary structures?

Primary - covalent peptide bonds Secondary - hydrogen bonds between the polypeptide backbone Tertiary - a mix including hydrogen bonds, disulfide bridges, ionic bonds, hydrophobic interactions, and Van der Walls forces Quarternary - non-covalent interactions like h-bonds, ionic bonds, hydrophobic interactions, and disulfide bridges between polypeptide chains

What are the formations associated with the second structure?

Alpha helixes and beta sheets

What type of bond forms alpha helixes and beta sheets?

H-bonds

What can cause denaturation?

High or low pH, high temp, nonpolar solvents

What causes denaturation of a protein? (Hint: Make sure to pick the 'most' correct answer.) Question options: Basic environments (i.e., ph > 9) High heat (i.e., >212 F or 100ºC) All of these answers are correct. Acidic environments (i.e., pH < 2).

All of these answers are correct.

How many water molecules would be produced in making a polypeptide that is 14 amino acids long? (Hint: First figure out how many waters would be produced by joining two amino acids together. Then do the same for three amino acids. Once you understand the pattern the question is straightforward.) Question options: 28 14 13 0

Which of the following amino acids has an aromatic R group? (Hint: You will need to look at a table of amino acids. There is one provided on pp. 90 (Fig. 5.2) of the textbook and two such tables in the lecture notes. You will need to find each amino acid in the table based on its name. Then with your knowledge of the shape of aromatic molecules, you will be able to pick the correct choice.) Question options: Leucine Tryptophan Glycine Glutamate

Tryptophan

Use the amino acid structures on pp. 90 (Fig. 5.2) in the textbook to answer this question. You are studying a protein with aspartic acid in a position that is important for stabilizing its structure. If this aspartic acid changes to a different amino acid due to a mutation, which of the following amino acid substitutions would be the MOST likely to allow the protein to fold normally? Question options: Threonine Glycine Serine Glutamic acid Arginine

Glutamic acid

Peptide bonds between amino acids form the __________ structure of a protein. Question options: primary tertiary quaternary secondary

primary

Two major types of protein secondary structures are referred to as: Question options: Elementary and primary. Residual and permanent. Amino and carboxyl. Ionic and covalent. α helix and β sheet.

α helix and β sheet.

At physiological pH, the ionized state of the amino (NH2) group in the R group of lysine is: (Hint: Lysine is an amino acid. You can view its structure in the table of amino acids found in the book on pp. 90 (Fig. 5.2), or in the table of amino acids in the lecture notes.) Question options: NH- NH2 NH3+ NH4+2

NH3+

Which of the following amino acids is most likely to be found on the outside of a properly folded protein in the cytoplasm? (Hint: You will need to view a table of amino acids such as found on pp. 90 (Fig. 5.2) of the textbook or in the lecture notes. Keeping in mind that proteins are surrounded by water, the answer should be straightforward.) Question options: Glycine Proline Serine Valine

Serine

When a peptide bond is created between two amino acids: Question options: the amino group of the first amino acid is joined to the amino group of the second. the carboxyl group of the first amino acid is joined to the amino group of the second. the amino group of the first amino acid is joined to the carboxyl group of the second. the carboxyl group of the first amino acid is joined to the carboxyl group of the second.

the carboxyl group of the first amino acid is joined to the amino group of the second.

Which of the following would affect the secondary structure of a protein? (Hint: Each of these affects a different level of protein structure. Can you identify the level of structure that would be disrupted for each answer?) Question options: Disruption of the interactions between two separate polypeptide chains. Changing the sequence of the amino acids. Disruption of ionic bonds that hold the R-groups of amino acids together. Disruption of the hydrogen bonds that hold different regions of the poly-peptide backbone together.

Disruption of the hydrogen bonds that hold different regions of the poly-peptide backbone together.

Which of the following amino acids has a non-polar R group? (Hint: You will need to look at a table of amino acids. There is one provided on pp. 90 (Fig. 5.2) of the textbook and two such tables in the lecture notes. You will need to find each amino acid in the table based on its name. Then with your understanding of electronegativity, look at the R-group to determine if it contains only non-polar covalent bonds.) Question options: Lysine Leucine Threonine Aspartate

Leucine

A burn caused by boiling water causes proteins inside your cells to lose their functions. Explain why the high temperature causes this to happen. Question options: The increased temperature disrupts weak interactions such as hydrogen bonding, which causes the proteins to lose their tertiary structures and abilities to bind specific molecules. The increased temperature disrupts covalent bonds such as peptide bonds, which causes the proteins to lose their tertiary structures and abilities to bind specific molecules. The increased temperature disrupts covalent bonds such as peptide bonds, which causes the proteins to lose their primary structures and abilities to catalyze reactions. The increased temperature disrupts weak interactions such as hydrogen bonding, which causes the proteins to lose their primary structures and abilities to catalyze reactions.

The increased temperature disrupts weak interactions such as hydrogen bonding, which causes the proteins to lose their tertiary structures and abilities to bind specific molecules.

Which one of the following can contribute to a protein's tertiary structure? Question options: Ionic interactions All of the other answer options are correct. Hydrogen bonds Covalent bonds

All of the other answer options are correct.

Using the structures of amino acids (you will need to look at pp. 90 (Fig. 5.2) in the textbook, refer to the lecture notes, or look this up online), determine which one of the following amino acids is MOST likely to participate in hydrogen bonding with water? (Hint: Here, you will need to find the amino acid in the table based on its name. Using your understanding of electronegativity, then look at its R-group to determine if it undergoes H-bonding.) Question options: Asparagine Valine Alanine Leucine Phenylalanine

Asparagine

Most proteins retain metabolic activity when denatured. Question options: True False

False

New amino acids add to a peptide at its: Question options: N terminus. 5’ end. 3’ end. C terminus.

C terminus.

At physiological pH (i.e., pH 7), the ionized state of the carboxyl (COOH) in the R group of aspartic acid is: Question options: CO-O- COO- COOH COOH+

COO-

The R-group of a basic amino acid is: (Hint: Use the amino acid structures on pp. 90 (Fig. 5.2) in the textbook to view the basic amino acids. These include lysine, arginine, and histidine.) Question options: positively charged at pH 7 and thus could bind DNA. hydrophobic and thus will be located in the interior of a protein. likely to form covalent bonds with other amino acids, in a way similar to how peptides in insulin are held together by covalent bonds. both polar and hydrophobic

positively charged at pH 7 and thus could bind DNA.