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
