Cell Biology Exam 1 Flashcards
Do mistakes in the DNA sequence have a positive, negative, or natural effect? (or all)
Depending on where they occur, can have positive, negative, or neutral effects on cell growth and survival.
What effects do positive change have in the DNA sequence?
effects on survival and reproduction can lead to the enrichment, called selection, of cells with that change in the population.
The products of the ATP hydrolysis reaction
ADP and free phosphate—are more stable and have a lower free energy.
Are free phosphates energetically favorable?
Yes, because it relieves the repulsion of the negative charges of the neighboring phosphate groups and the aqueous environment to make hydrogen bonds with the phosphate.
Amino acids like glutamic acid and aspartic acid have side chains that terminate in carboxylic acid groups (−COOH). Is it acidic and how does water impact?
This group loses a proton in water and is acidic in nature.
What is the measure of disorder in a system called?
Entropy. The second law of thermodynamics states that systems will change spontaneously toward arrangements with greater entropy.
1st Law of Thermodynamics
Energy cannot be created or destroyed
2nd Law of Thermodynamics
For a spontaneous process, the entropy of the universe increases.
3rd Law of Thermodynamics
A perfect crystal at zero Kelvin has zero entropy.
What type of reaction is sometimes also termed “energetically favorable.”
A reaction occurs spontaneously only if the change in free energy (ΔG) is negative, which means that it is increasing the disorder in the system by decreasing the free energy.
What are energetically unfavorable reactions and how do they occur?
If they are coupled to a second reaction with a negative ΔG so large that the net ΔG of the entire process is negative. This type of coupling allows the cell to build the molecules necessary for life.
What is the definition of free energy?
Energy that can be harnessed to do work or drive chemical reactions. The release of free energy increases the disorder of the universe.
Importance of fruit flies?
They have been studied for over a century, and their complex body plan can be manipulated genetically to uncover which genes govern development of which parts. Many of these genes have direct counterparts in the human genome.
The importance of potassium and is it necessary?
Life is tightly regulated and enormously complex, is dominated by collections of polymers, is based overwhelmingly on carbon-containing compounds, and takes place almost exclusively in water. It is important to some biochemical reactions, but there is not an overwhelming dependence on potassium-containing compounds to sustain all life.
Do fatty acids have both hydrophobic and hydrophilic components? What is the name of this?
Yes, it is the term used to describe fatty acids like this that have both hydrophobic and hydrophilic components within the same molecule. Molecules like this are polar on one end and nonpolar on the other.
What bonds are hydrophobic?
Bonds between carbon and hydrogen are nonpolar and molecules with mostly nonpolar bonds are
What bonds are hydrophilic?
Bonds between H and electronegative atoms like O and N are polar and tend to impart
When an enzyme lowers the activation energy for the forward reaction X → Y, it also lowers the activation energy for….
the reverse reaction Y → X by the same amount. The equilibrium point for the reaction thus remains unchanged.
A hydrogen is what type of force?
Intermolecular
Hydrogen bonds link what?
the two polynucleotide chains to each other in a double helix of DNA.
What bonds are the strongest in the cells?
Covalent bonds, these bonds are resistant to being broken apart by thermal motion or dissolution in water.
In molecules held together by polar covalent bonds, where will the positive and negative charge concentrate?
The positive charge will be concentrated toward one end of the molecule and the negative charge toward the other. This is due to an unequal sharing of electrons across the covalent bond.
Will dissolving salt in water results in increased or decreased disorder?
increased because dissolving salt will destroy its ordered, crystalline form.
Which functional groups contain polar oxygens that can form hydrogen bonds with water to enhance solubility?
Both the hydroxyl and carboxyl groups
The formation of what must be coupled to an energetically favorable reaction?
activated carriers
What does the cell theory state?
That all cells are formed by the growth and division of existing cells. Therefore, living things do not spontaneously arise, but must come from other living organisms.
The equilibrium constant is a ratio of what two things?
Ratio of product to substrate where [X] is the concentration of product and [Y] is the concentration of substrate at equilibrium.
What two things contain their own DNA?
Chloroplasts, like mitochondria, contain their own DNA and reproduce by dividing in two. Both are thought to have evolved by symbiotic engulfed bacterial cells, but in two separate engulfment events.
What happens when two macromolecules in a cell come together in a very specific way?
come together through many weak noncovalent associations between them. This allows more specificity, but also easier reversibility, as molecular interactions often must be relatively short lived in cells.
Different molecules diffuse through the cytosol at different speeds, and in general, the smaller the molecule is faster or slower?
the faster it will diffuse through the cytosol. CO2 is a gas, tyrosine is an amino acid, succinate dehydrogenase is an enzyme, and a ribosome is a large complex of proteins and RNA.
The energetically favorable hydrolysis of ATP is coupled to many what?
otherwise energetically unfavorable biosynthetic reactions
Glucose is an example monomer of a
polysaccharide
Alanine is an amino acid used to make?
Proteins
Polysaccharides, proteins, and nucleic acids are made from what?
monomeric subunits
macromolecule is a polymer formed from what?
small molecules
small molecules are called?
monomers or subunits
monomers and subunits are linked together by?
covalent bonds
Alanine is an example monomer?
protein
Guanosine triphosphate is an example monomer of?
nucleic acid
An example of a model plant?
arabidopsis thaliana, the common wall cress
The genome of the bacterium E. coli contains how many nucleotide pairs?
4.6 million (4.6 × × 106)
The human genome contains about how many nucleotide pairs?
3200× 106
What can be concluded based on the numbers between the genome of humans and the genome of bacterium E. coli?
What can be concluded based on these numbers? - can not conclude anything
For the reaction A + B → AB, the equilibrium constant expressed for this reaction with two substrates and a single product is: K = [AB] / [A][B]. What is the concentration of the product?
The numerator for this expression.
What causes the interchangeably function in yeast and human cells, that links back billions of years?
the proteins that control cell division between the two are functionally equivalent
A molecule of water is lost with the addition of each monomer to the growing polymer chain. Water is removed and a new bond is created between the growing polymer and the newly added monomer.
What kind of reaction is this?
condensation reactions
At a molecular level, the members of the two domains of prokaryotes—the archaea and bacteria—differ as much from each other as either does from the eukaryotes.
as many differences and as many similarities
prokaryotes
organisms whose cells lack a nucleus and other organelles.they are divided into two distinct groups: the bacteria and the archaea, which scientists believe have unique evolutionary lineages. Most prokaryotes are small, single-celled organisms that have a relatively simple structure.
eukaryotes
organisms whose cells contain a nucleus and other membrane-bound organelles. There is a wide range of eukaryotic organisms, including all animals, plants, fungi, and protists, as well as most algae. Eukaryotes may be either single-celled or multicellular.
bacteria and archaea, similarities and differences
Similar to bacteria, archaea do not have interior membranes but both have a cell wall and use flagella to swim. Archaea differ in the fact that their cell wall does not contain peptidoglycan and cell membrane uses ether linked lipids as opposed to ester linked lipids in bacteria.
Metabolism
is the sum total reactions in a cell, which are of two types (catabolic and anabolic reactions
catabolic reactions
break complex molecules down into simpler ones, releasing chemical energy.
Anabolic reactions
use energy to build complex molecules from simpler organic compounds (e.g., proteins from amino acids, carbohydrates from sugars, fats from fatty acids and glycerol)
Activated carriers collect what?
electrons from oxidation of molecules in catabolic reactions and transfer them to anabolic reactions that require electrons for the reduction of molecules.
Does a single covalent bond allow for rotation about the bond axis?
Yes, a single covalent bond between two atoms generally allows the rotation of one part of a molecule relative to the other around the bond axis.
What length and strength are double and triple bonds?
shorter and stronger than single bonds and have a characteristic effect on the geometry of molecules containing them.
amphipathic
The hydrophobic regions cluster at the membrane’s center, where they can avoid contact with water, while the hydrophilic portions face the outside of the membrane, where they interact with water.
Substances that release protons when they dissolve in water are termed what and result in a pH lower than what?
termed acids and lower than 7. These protons, once released from the acid, associate with water and generate a hydronium ion. An increase in the concentration of hydronium is what lowers the pH value.
the activation energy barrier
An enzyme lowers the activation energy for one specific reaction leading to one product. The activation energy barrier prevents the molecule from immediately being converted to product. To overcome, either the energy of the molecule must be increased or the barrier must be lowered before the reaction can proceed.
Two monosaccharides can be linked by a covalent glycosidic bond to form a disaccharide. This reaction belongs to a general category of reactions termed condensation reactions, in which two molecules join together as a result of the loss of a water molecule. The reverse reaction (in which water is added) is termed
hydrolysis
A condensation reaction
joins two monomers together, releasing water.
bonds that link components together involve the sharing of electrons between atoms
covalent bonds
A hydrolysis reaction
uses water to split the bond that joins two subunits of a polymer.
bonds that links that involve electrostatic interactions between atoms
noncovalent bonds
Every amino acid includes a carboxyl group and an amino group. These functional groups are part of
all amino acids and they are directly involved in the creation of the peptide bond that forms the protein backbone.
Hydrophilic molecules dissolve in
Water, Indeed, the term hydrophilic means “water-loving.”
Covalent bonds are strong and are used within molecules to form the linkages between
monomers that form the polymer
Noncovalent bonds are important for
the three-dimensional conformation and for interactions with other molecules.
Energetically favorable reactions are those that create
disorder by decreasing the free energy of the system to which they belong. Such reactions have a negative ΔG. Both chemical and biological reactions must adhere to the laws of thermodynamics.
Unsaturated fatty acids may be what kind of bond?
monounsaturated (containing one double bond) or polyunsaturated (containing multiple double bonds).
Saturated fats
are more solid at room temperature and can pack very closely together and create a far denser substance. A cell’s plasma membrane with a greater degree of saturated hydrocarbons will exhibit less fluidity at room temperature. More saturated hydrocarbons is associated with a denser, more solid substance as opposed to more fluid and less dense.
There are three types of kingdoms in living organisms
- Bacteria ( non photosynthetic bacteria, photosynthetic bacteria)
- Eukaryote ( plants, animals, fungi)
- Archaea ( archaea )
Cells obtain energy from the ______ of organic molecules?
oxidation
How does ATP provide energy for key processes to occur
When delta G is negative, things are favorable, positive means unfavorable
In order for cells to function they must exist in a state of chemical equilibrium
false, all the reactions that are creating energy are not at equilibrium
the equilibrium constant of a reaction, as in K= [AB] / [A][B], is indicative of its strengths
True
How are energetically unfavorable reactions able to occur in cells
Coupling with the dissociation of activated carriers can make them run
Km and Vmax are terms describing
enzyme properties
the association of the enzyme with the substrate molecule can be described how?
Km
Primary proteins
linear amino acid sequence
Secondary proteins
folding patterns
Tertiary proteins
3D organization of secondary structures protein domains
Quaternary proteins
Organization of protein complexes
which of the four types of amino acids is represented by the most members
Non-polar
4 Types of amino acids - sometimes these are not interchangeable in structures and sometimes not
Negatively charged
Positively charged
Uncharged polar
Non-polar
which sequence of amino acid side chains would most likely be found on the outside of the structure
Acidic - acidic - uncharged polar
Needs to be two charged and one uncharged
a proteins primary structure is dependent upon _____ bonds that _____.
Peptide ; link adjacent amino acid
specific membrane compartments such as lysosomes and peroxisomes can be isolates from cell lysates by differential conterfugion
true
