- What is the difference between an endergonic and an exergonic reaction?
Endergonic Reactions are reactions that absorb energy.
Exergonic Reactions are reactions that give off energy.
- How many protons, neutrons, electrons, and valence electrons does Na+ have? (the atomic number for sodium is 11)
Protons: 11
Neutrons: 11
Electrons: 10
Valence Electrons: 8
- What is the difference between an ionic bond and a covalent bond? Which is stronger?
Covalent bonds are stronger than ionic bonds. Ionic bonds are the gain or loss of electrons that result in a bond formed between ions (either cations or anions). Covalent bonds are the sharing of atoms.
- What are the four types of organic macromolecules and which monomers link together to make up each?
Polypeptides (proteins)- made up of amino acids
Polysaccharides (starches)- made up of monosaccharides
Lipids (fats)- made up of fatty acids
Nucleic Acids (DNA and RNA)- chains of amino acids
- Which type of bond holds together the monomers that make up the four primary organic macromolecules?
Covalent bonds hold together the monomers of the four primary organic macromolecules.
- Which type of bonds hold together two complementary strands of DNA?
Hydrogen bonds hold together complimentary strands of DNA.
- Why do phospholipids form micelles in water?
Phospholipids form micelles in water because they have hydrophobic and hydrophilic regions.
- What is the difference between a saturated and an unsaturated fatty acid?
Saturated fatty acids have the maximum amount of hydrogen atoms possible for each carbon (all single bonds). Unsaturated fatty acids have double bonds and there are not the maximum number of hydrogen atoms on each carbon.
- Often times science fiction stories make reference to silicon-based life forms as opposed to carbon-based life. Why does this make sense as a plausible possibility for alien life?
Silicon-based life forms are a plausible possibility because it has four valence electrons that allow for the attachment of four possible atoms or molecules, similar to carbon.
- What are the three differences between DNA and RNA?
The sugars in DNA and RNA are different (DNA has a deoxyribose while RNA has a ribose), DNA forms a double helix and RNA is a single spiral, and DNA uses the thymine base, while RNA uses Uracil.
- What are the five nitrogenous bases that form the eight nucleotides that make up RNA and DNA?
The purines are Adenine (A) and Guanine (G). The pyrimidines are Cysteine (C), Thymine (T), and Uracil (U).
- How do nucleotides fit together to form DNA? (draw it!)
The nitrogenous bases pair. Adenine pairs with Guanine in DNA and RNA, Adenine pairs Thymine in DNA and Uracil in RNA. These pairs alternate and build upwards creating a spiral staircase that is bounds by hydrogen bonds.
- What causes proteins to fold into their final shape?
Quaternary structure causes the proteins to fold into their final shape.
- What is the difference between a protein’s primary structure, secondary structure, tertiary structure, and quaternary structure?
Primary Structure: the specific sequence of the amino acid in a polypeptide chain.
Secondary Structure: the folding and coiling of amina acids in a particular pattern (alpha helix, beta sheets…)
Tertiary Structure: further folding into globular or fibrous shapes
Quaternary Structure: association of several tertiary structure polypeptide chains.
- What causes the structural shape of receptors to change?
The binding of a ligand causes the shape of the receptors to change.
- What would happen if an enzyme were absent from a cell?
The cell would not function, as the enzyme is a catalyst for the chemical reactions of the cell.
- What would happen if a cell had too much of a particular enzyme?
If there is too much of an enzyme, the cell usually tells it to shut that particular enzyme. As far as cells are concerned, depending on what the enzyme is, it may cause problems or it may not. It really depends on enzyme is present and the effect is has on the cell.
- Why are enzymes highly specific for their substrates and receptors highly specific for their ligands?
The enzyme’s substrates and receptor binding sites are highly specific because the chemical reactions that are needed to run are highly specific.
- Based on its name, what do you think proteases do?
(Hint: these are also called peptidases)
Proteases break down proteins.
Confirmed.
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