Exam 1 Flashcards
In a single molecule of water, two hydrogen atoms are bonded to a single oxygen atom by ________
Polar covalent bonds
Which of the following is true about a scientific theory?
It is a comprehensive set of ideas explaining a phenomenon in nature
Using only single bonds, how many hydrogen atoms would it take to covalently bond with one sulfur atom for the molecule to become most stable?
2
How many full orbitals are in oxygen?
7
What kind of bond is formed between two molecules when a transfer of electrons takes place to form the resulting molecule?
Ionic
What type of chemical reactions are responsible for linking monomers together to build polymers?
Condensation
What types of bonds are found between the monomers of proteins?
Peptide bonds
What are the monomers of proteins?
Amino acids
If you wanted to slow down or stop an enzymatic reaction, what could you do?
Change the pH of the environment
Raise the temperature to an extreme
Increasing the substrate concentration in an enzymatic reaction could overcome which of the following?
Competitive inhibition
What are the monomers of nucleus acids?
Nucleotides
What types of bonds are found between the monomers of nucleus acids?
Phosphodiester bonds
What are the characteristics of living things?
Respond to the environment Different levels of organization Made up of cells Grow and develop Obtains and uses energy Reproduce
What is the scientific theory?
A comprehensive set of ideas explaining a phenomenon in nature
Based on Pasteur’s experiment, was the spontaneous generation hypothesis supported in the straight neck flask and the swan neck flask?
Only the straight neck flask supported the hypothesis
What is spontaneous generation?
Living things can appear from non-living things
What did Pasteur’s experiment support?
All cells come from preexisting cells
What is an alternative hypothesis?
Says there is a statistical difference between the two variables
What is a Null hypothesis?
Says there is no statistical difference between the two variables
Does a supported hypothesis prove anything?
No, if a hypothesis is supported, it adds to scientific evidence that supports or does not support a claim
What is a control group?
The group that is being compared to
What is the experimental group?
The group you are testing
What is the independent variable?
The variable that is changed (you change)
What is the dependent variable?
The variable that is measured
What are constants?
Variables that are not changed throughout the experiment, the ones that remain the same
What is matter?
Takes up space and has a mass
What is an element?
Substance that is in its simplest form
What 4 elements make up 96% of life?
Nitrogen, hydrogen, oxygen, and carbon
What is a compound?
Two or more elements bonded together
What is the order of organization?
Atom Molecule Cell organelles Cell Tissue Organ Organ system Organism Population Biocenoses Ecosystem Bioma Biosphere
How many electrons and protons are in a Ca+2 ion when it’s atomic number is 20?
20 protons, 18 electrons
What is atomic number?
#of protons (Number of electrons in an uncharged atom)
What is mass number?
Protons + neutrons
What is the electron shell?
Where the electrons orbit around the nucleus
What is the orbital?
Composed of two electrons
What is the nucleus?
Composed of protons and neutrons
How many hydrogen atoms can bond with sulfur (atomic #16)?
2
What are covalent bonds?
Share electrons
Have different electronegativity
What are ionic bonds?
Transfer electrons
- cations-positively charged
- anions-negatively charged
What is a hydrogen bond?
Have electrical attraction by partial charges
- weak
- when hydrogen bonds to F, O, or N
What is the difference between Polar-covalent bonding and non-polar covalent bonding?
Non-polar: atoms spend the same amount of time around all atoms and have similar electronegativity
Polar: spends more time around one atom than the other atoms and have different electronegativity
What are the characteristics of polar covalent bonds?
- Electrons are not shared equally
- Atoms have different electronegativity
- Spend more time around one atom compared to others in the molecule
- Soluble in water
What are the characteristics of non-polar covalent bonds?
- Electrons are shared equally
- Atoms have the same electronegativity
- Atoms spend the same amount of time around all atoms
- not soluble in water
What characteristic is shared between polar and non-polar covalent bonds?
Both share electrons
What are the properties of water?
- expands when it freezes
- Great solvent
- cohesion
- adhesion
- surface tension
If a non-polar molecule is mixed in with a polar molecule, what will happen?
The two will not dissolve
The two will repel each other
What is soluble in water?
Polar molecules
Ions
LIKE DISSOLVES LIKE
What bonds form when a polar molecule mixes with water?
Hydrogen bonds
What is cohesion?
Water molecules sticking together
What is adhesion?
Water sticking to other substances
What is surface tension?
Property of the surface of water that allows a resistance of an external force
How can I link two monomers together?
Take water away (Condensation reaction)
What are proteins built from?
Amino acids
How are amino acids linked?
Peptide bonds
What is the first level of protein structure?
Primary structure: individual amino acids are linked by peptide bonds and form polypeptides
What is the second level of protein structures?
Secondary structure: protein ms fold through hydrophobic interactions and hydrogen bonding to form alpha helices or beta-pleated sheets
What is the third level of protein structure?
Tertiary structure: amino acids sidechains continue to interact and bond in different ways to form the whole protein
This structure has covalent bonds, ionic bonds, hydrogen bonds, disulfide bridges, and vanderwaal’s forces
What is the fourth level of protein structure?
Quaternary Structure: proteins interact with one another to carry out their specific functions
Which of these types of bonds are present in the TERTIARY structure?
Covalent
Ionic
Hydrogen
Vander Waal’s forces
What happens when proteins are folded incorrectly?
Misfolded proteins are called prions
Lead to cruddy diseases like Mad Cow Disease (AKA Kuru)
What do proteins make up?
Enzymes
What do enzymes do?
Lower reaction activation energies and allow reactions to occur much faster
What do enzymes require?
Specific temperature and pH
What is competitive inhibition?
When another molecule competes for the active site on the enzyme
However, the non-substrate molecule can not work with the enzyme, meaning it can still carry out its job
-means fewer places for the substrate to bind with the enzyme
This type of inhibition can be overcome by increasing the amount of substrate
What is non-competitive inhibition?
When another molecule binds to the enzyme and changes it’s confirmation
Means the substrate is no longer able to bind and carry out the enzymatic reaction
This type of inhibition can only be overcome with Allosteric Activation
What does allosteric activation do?
It activates an inhibited enzyme/substrate complex
With allosteric activation, a molecule binds on to an enzyme at a site away from the activation site
- this pushes the inhibiting molecule off of the enzyme
- the enzyme’s original confirmation is restored
What is feedback inhibition?
When enough of a product is made, that product can inhibit the enzyme and tell it to not make any more product until it is needed
X binds to enzyme Y. In doing so, it changes its confirmation and substrate Z can no longer bind. When we add a large amount of substrate Z, the reaction continues again at its normal rate. What type of inhibition is this?
Competitive
What are the building blocks of nucleic acids?
Nucleotides
What types of bonds hold nucleotides together?
Phosphodiester
What are the purines?
Adenine and guanine
What are the pyrimidines?
Thymine and cytosine
What bases bind together in DNA?
A with T
C with G
What does RNA have in place of thymine?
Uracil
What is ATP considered?
A nucleic acid
What does ATP do?
Holds energy in living organisms
Consists of an adenine, ribose sugar, and three phosphate groups
Energy comes when a phosphate is released
Which process results in the release of energy?
A phosphate group is released
A strand of DNA is made up of 20% A and 30% C. What percent of it is U?
0%
URACIL IS IN RNA
What are carbs?
Monosaccharides in ring-formation
What is starch?
Plant energy storage
What is glycogen?
Animal energy support
What is cellulose?
Structural support in plant cell walls
What is Chitin?
Structural support in the cell walls of fungi and exoskeletons
What is peptidoglycan?
Structural support in bacterial cell walls
What polysaccharide do humans use, and where is it stored in the body?
Glycogen; liver
What are lipids made of?
Fatty acids And glycerols
Can be phospholipids or triglycerides
What are monomers of lipids?
Glycerols and fatty acids
What are triglycerides?
- They store fat
- They give us energy when we don’t have as many carbohydrate sources in our bodies form which to obtain energy
- They contain three fatty acids attached to the glycerol backbone
What are phospholipids?
- They make up the outer membranes of cells
- They let in and out what is needed by the cell
What do phospholipids consist of?
Two fatty acids and phosphate group attaches to the glycerol backbone
The charged phosphate makes the phospholipid amphioathic, meaning it can mix with both fat and water
They are crucial to digestion and break down other fats so they can be better carried through the blood stream
What is a cell membrane?
A semi-permeable membrane that protects the cell, it only lets in certain molecules, electrolytes, etc. inside the cell
What is the cell membrane made of?
Peripheral membrane proteins Carbohydrates Extra cellular matrices Integral proteins Cholesterol Phospholipids Cytoskeleton
What are phospholipids considered?
They are a type of lipid molecule
What are lipids made of?
Fats, waxes, and vitamins
What is a major job of phospholipids?
They are the main component of the cell membrane
How do phospholipids make up the membrane?
By aligning themselves based upon water-liking (hydrophilic) and water-hating (hydrophobic) properties
What do phospholipids consist of?
Two fatty acids, a phosphate group, and a glycerol molecule
What are the characteristics of saturated fats?
- They are saturated with hydrogen molecules
- they are solid at room temperature
- Make the membrane less permeable
What are the characteristics of unsaturated fats?
- Use double bonds to form kinks and are NOT saturated with hydrogen
- are liquid at room temperature
- makes the membrane MORE permeable
What else changes membrane fluidity?
Temperature
Cholesterol
If I was looking at a cell membrane, where would I see the phospholipids?
The inside
What gets thorough cell membrane?
Small, nonpolor molecules (CO2, N2, O2)
Small, uncharged polar molecules (H2O, Glycerol)
What doesn’t get through cell membrane?
Large, uncharged polar molecules (Glucose, Sucrose)
Ions (Na+, K+, Cl-)
What do you think will EASILY pass through a semi-permeable cell membrane?
Oxygen atoms
When does diffusion occur?
When molecules move from high to low concentrations
What is it called when water diffuses?
Osmosis
How does osmosis work?
Water moves from low concentrations of solute to high concentrations it solute
What is facilitated diffusion?
Molecules are helped out by membrane proteins
These can be channel proteins or gated channel proteins, which open when receptors bind
What is active transport?
Proton pumps push ions (Na+, K+, etc.) AGAINST their concentration gradients
Ions move from low to high concentrations
Only type that uses energy
If I’m a giant molecule of glucose, how can I get across the cell membrane?
I need ATP to give out energy and shot me across the membrane
What is the anatomy of an experiment?
1) Observation/Ask a question
2) Develop a Hypothesis
3) Design the Experiment
4) Predictions
5) Perform Experiment/Data Collection
6) Data Analysis/ Conclusions
What does the atomic number of an atom tell us?
of protons (In an uncharged atom also the # of electrons)
What does the mass number (atomic weight)?
of protons + # of neutrons
What is the difference between an ionic bond, a covalent bond, and hydrogen bond?
Ionic: form when electrons are transferred between atoms
Covalent: form when electrons are “shared” between atoms
Hydrogen: formed by electrical attraction of the partial charges of polar molecules
How are polar covalent bonds different from non-polar covalent bonds?
Polar: electrons NOT shared equally
Non-polar: electrons shared equally
What does it mean for a molecule to be “polar”?
there is a negative side and a positive side
What are the five properties of water?
Expands as it freezes Excellent Solvent Cohesion Adhesion Surface Tension
How do hydrogen bonds lead to water expanding as it freezes?
hydrogen bonds formed between water in liquid state are not as rigid as w/ ice; this allows for ice to be less dense (more rigid of a bond) than liquid water
As water freezes the H-bonds push the H20 molecules farther apart from each other increasing the intermolecular space resulting in expansion
How do hydrogen bonds lead to water being an excellent solvent?
hydrogen bonds allow it to form weak bonds w/ other polar substances
How do hydrogen bonds lead to water being able to have cohesion?
the hydrogen and the water molecules form weak bonds with each other
How do hydrogen bonds lead to water being able to have adhesion?
the hydrogen and the water molecules form weak bonds with other polar substances (makes water sticky)
How do hydrogen bonds lead to surface tension?
the hydrogen bonds allow it to form weak bonds with each other in order to push back and create tension and resistance of an external force
Does water form hydrogen bonds with polar molecules?
yes because it has a charge
Does water form H-bonds with non-polar molecules?
no because there is no charge
Does water form H-bonds with ions?
yes because they have a charge
In the chemical reaction that forms proteins, is a water molecule added or removed?
water is removed in a condensation reaction
What type of bonds from between amino acids?
peptide bonds
What is the first level of protein structure?
Primary structure: individual amino acids are linked by peptide bonds and form polypeptides
Hydrogen bonds
What is the second level of protein structure?
Secondary structure: protein fold through hydrophobic interactions and hydrogen bonding to form alpha helices or beta-pleated sheets
Hydrogen and Peptide bonds
What is the third level of protein structure?
Tertiary structure: Amino acid side chains continue to interact and bond in different ways to form the whole proteins
Covalent bonds, ionic bonds, hydrogen bonds, disulfide bridges, and vanderWaal’s forces
What is the fourth level of protein structure?
Quaternary structure: In this structure, proteins interact with one another to carry out their specific functions
Same bonds al tertiary
What does it mean for a protein to be denatured?
it means the protein is being taken back down the its secondary structure, the tertiary and quaternary structures are getting broken down
How can denaturation can occur?
through heating the protein to an extreme temperature chemical denaturation(change in pH)
Are all proteins considered to be enzymes?
No
How do proteins speed up chemical reactions?
By acting as a catalysts which lowers the activation energy
What is activation energy?
the energy needed for for the chemical reaction to take place
How are enzymatic reactions regulated?
by inhibitors, temperature, and pH
What is feedback inhibition?
when the product of the enzyme reaction is made in excess and starts to inhibit the reaction until more is needed again
(when enough of the product is made, that product can inhibit the enzyme and tell it to not make any more product until it is needed)
What are the monomers of nucleic acids?
nucleotides
In the chemical reaction that forms nucleic acid polymers, is a water molecule added to removed?
Removed in a condensation reaction
What type of bond forms between these monomers in a single strand?
Phosphodiester bonds
What are the major differences between DNA and RNA?
DNA: double stranded, has Thymine as a base, doesn’t have the O
RNA: single stranded, has Uracil as a base, has that O
Which DNA nucleotides bond with each other?
A bonds with T and C bonds with G
What types of bonds are found between the bases of the two different strands of DNA (hold together the two different sugar-phosphate backbones)?
Hydrogen Bonds
How do the three phosphate groups on an Adenosine Triphosphate (ATP) molecule allow this molecule to carry energy?
energy comes from the breaking of the bonds between phosphates
What are the monomers that make up carbohydrates?
monosaccharides
In the chemical reaction that forms polysaccharides, is a water molecule added or removed?
removed in a condensation reaction
What type of bond forms between these monosaccharides?
glycosidic bonds
One small change in a monosaccharide will lead to a major change in the final folded molecule. This change will give the monosaccharide a different name, shape, and function. What are some of these factors of change?
carbonyl group placement, carbon number, hydroxyl group placement, and presence of isotopes
What is glycogen?
energy in animals
What is starch?
energy in plants
What is chitin?
structure in animals and fungi
What is cellulose?
structure in plants
What are the monomers of lipids?
Glycerol + Fatty acids
In the chemical reaction that forms lipids, is a water molecule added or removed?
removed in a condensation reaction
What type of bonds form between the monomers of lipids?
ester bonds
What is a phospholipid?
a glycerol, hydrophilic head and hydrophobic fatty acid tails
How does the structure of a phospholipid change if saturated fats are used as the “fatty acid” portion of the molecule?
membrane is less permeable
How does the structure of a phospholipid change if unsaturated fats are used as the “fatty acid” portion of the molecule?
membrane is more permeable due to kinks
How does the addition of saturated fatty acids, unsaturated fatty acids, or cholesterol affect permeability and/or fluidity of a cellular membrane?
- Saturated fatty acids reduce both
- Unsaturated fatty acids increase both
- Cholesterol reduces permeability
What role does temperature play in the permeability and fluidity of cell membranes?
colder temperatures reduce permeability and fluidity
What is diffusion?
when molecules move from high to low concentrations
how the “in crowd” gets through the semi-permeable membrane
does not require ATP
What is osmosis?
when water diffuses, still moves from high to low concentration but its more of it moving from low concentrations of solute to high concentrations of solute
does not require ATP
What is facilitated diffusion?
when molecules are helped out by membrane proteins
can be chemical proteins or gated channel proteins that open when receptors bind
(channel proteins are like tunnels)
(gated channels are like toll booths)
does not require ATP
What is active transport?
proton pumps push ions (Na+, K+, etc) AGAINST their concentration gradients
Ions move from LOW to HIGH concentrations
this takes ENERGY
only type that requires ATP
Is ATP needed to move a solute along a concentration gradient?
No
Is ATP needed to move a solute against a concentration gradient?
Yes
When is a solution considered to be Isotonic?
molecules flowing freely back and forth in equilibrium
When is a solution considered to be hypertonic?
more solutes, less water; water will flow out to it
When is a solution considered to be hypotonic?
less solutes, more water; water will flow in from it
How will a isotonic solution affect the shape of an animal cell?
will have no affect on the shape
How will a hypertonic solution affect the shape of an animal cell?
will shrink the cell
How will a hypotonic solution affect the shape of an animal cell?
will expand the cell
How does the Na+/K+ ATPase pump work?
look at slide picture
For every turn of of the cycle, how many Na and K ions are moved into and/or out of the cell?
3 Na and 2 K
Why does this pump need to use ATP?
because ATP breaking down into ADP is what gives it its energy to operate
What would the addition of phospholipids that contain saturated fatty acids to cellular membrane do?
it would reduce the membrane’s permeability
How many electrons are involved in a single covalent bond?
two
Why is each element unique with respect to its chemical properties? Each element has a distinctive ________
number of protons
The partial negative charge at one end of a water molecule is attracted to the partial positive charge of another water molecule. What is this attraction called?
the electrons shared between the oxygen and hydrogen atoms spend more time around the oxygen atom nucleus than around the hydrogen atom nucleus
What is the pH of a solution with a H+ concentration of 10^-12 M?
pH 12
What is true about water?
Water will dissolve molecules that are either polar or that have a charge
Two molecules are bonded together due to the attraction of their opposite, yet partial charges. What type of bond is described above?
polar covalent
Oil does not dissolve in water. Based on this fact, you know that the majority of the bonds in the molecules that make up the oil must be:
non-polar covalent
How might a scientific theory be modified?
by the uncovering of new information using the scientific method
What are two qualities of any good scientific hypothesis?
It is testable and it is falsifiable
What type of chemical reaction is responsible fro breaking polymers back down into monomers?
hydrolysis
How do enzymes increase the speed of certain biological chemical reactions?
by bringing reactants (also known as substrate) into physical contact with one another
Which of the following are pyrimidine nitrogenous bases?
cytosine and uracil
What are the components of each monomer used to make proteins?
A side chain, R
A carboxyl group, COOH
An amino functional group, NH2
What are prions?
misfolded versions of normal protein that can cause disease
When the atoms involved in a covalent bond have the same electronegativity, what type of bond results?
a nonpolar covalent bond
What component of amino acid structure varies among different amino acids?
the components of the R-group
Which of the following are purine nitrogenous bases?
guanine and adenine
A series of hydrophobic side chains will congregate together as a protein folds in an aqueous solution and be stabilized by ______.
van der Waals interactions
Enzymes that break down DNA catalyze the hydrolysis of the covalent bonds that join nucleotides together. What would happen to DNA molecules treated with these enzymes?
The phosphodiester linkages of the polynucleotide backbone would be broken
A covalent chemical bond is one in which ______
outer shell electrons of two atoms are shared so as to satisfactorily fill their respective orbitals
Bonds between two atoms that are equally electronegative are ________
nonpolar covalent bonds
Nitrogen (N) is more electronegative than hydrogen (H). Which of the following is a correct statement about the atoms in ammonia (NH3)?
Each hydrogen atom has a partial positive charge; the nitrogen atom has a partial negative charge.
In a single molecule of water, two hydrogen atoms are bonded to a single oxygen atom by ________
polar covalent bonds
What are bonds based on partial + or - charges between molecules?
hydrogen bonds
What are bonds based on the unequal sharing of an electron between two atoms?
polar covalent bonds
What are bonds based on the equal sharing of an electron between two atoms?
non-polar covalent bonds
What are bonds based on the transfer of an electron from one atom to another?
ionic bonds
Knowing the atomic mass of an element allows inferences about which of the following?
the number of protons plus neutrons in the element
Which of the following is a property of liquid water? Liquid water ________
has a heat of vaporization that is higher than that for most other substances
What are differences between DNA and RNA?
- The sugars differ between the nucleotides found in each
- One is most often double-stranded, while the other is usually single-stranded
- There are differences in the nitrogenous bases found in the nucleotides of each
What are the bonds that hold together complementary base pairs between the two strands of DNA?
hydrogen bonds
What is equilibrium?
an equal concentration of molecules on either side of the membrane
What is brownian motion?
the random movement of particles suspended in fluid (liquid or gas)
