Bio Concept 2 practice questions

Question 1

List the elemental composition, monomer, monomer structure, bonding linking monomers and location within a cell/function of protein

Answer 1

1. Carbon, hydrogen, oxygen, nitrogen
2. amino acids (20 amino acids with different R groups)
3. Amino acid =
   Base amino group
   Acidic carboxyl group
   1/20 side-chain groups (-R)
4. Peptide bond (carboxylic acid group on 1st joins to amino acid group on 2nd with loss of H2O)
5. Cytoskeleton
   Enzymes
   Also exported + used for enzymes, hormones, structural proteins (tissues), muscles, transport, defence

Question 2

List the elemental composition, monomer, monomer structure, bonding linking monomers and location within a cell/function of nucleic acids (DNA/RNA)

Answer 2

1. Carbon, hydrogen, oxygen, nitrogen, phosphorus
2. ATGC (U in RNA)
3. Nucleotide =
   Nitrogenous base
   Pentose sugar
   Phosphate group
4. Phosphodiester bond (phosphate on 1st binds to hydroxyl group at C3 of sugar ring on 2nd)
5. In the nucleus and nuclear region
   + Chromosomes + Also mitochondria and chloroplasts + used for Genetic material – all instructions to make an organism

Question 3

List the elemental composition, monomer, monomer structure, bonding linking monomers and location within a cell/function of carbohydrates

Answer 3

1. C, H, O
2. Saccharide (mono) names based on no. of carbons, triose, tetrose, pentose
   (polymer = 3 groups – mono , di, poly)
3. Cyclic/ring structure, if monosaccharide has 5 or more carbons
4. Glycosidic bond (monosaccharide joins to alcohol or 2nd monosaccharide with loss of H2O)
5. As energy storage in vacuoles
   + cell walls + exported
   Energy transport/storage
   Structural (cellulose) and used for Energy (glucose for ATP)

Question 4

List the elemental composition, monomer, monomer structure, bonding linking monomers and location within a cell/function of lipids

Answer 4

1. C, H, O, Phosphorus, Nitrogen
2. No monomer
   Simple lipids = alcohol groups + long chain fatty acids
   e.g. long chain fatty acids, waxes, triacylglycerols
3. Complex lipids
   Diverse structure, includes phospholipids, glycolipids, isoprenoids
4. Ester linkage (acid and alcohol with loss of H2O)
5. Cell membrane and used for Storage, protection, signalling (hormones), pigments, photoreceptors, cofactors.

Question 5

After a cow is given antibiotics to treat an infection, a vet gives the animal a drink of “gut culture” containing various prokaryotes. Why is this necessary?

Answer 5

Because antibiotics are not specific – they will kill all microorganisms, including the natural flora of the animals gut. This natural flora is vital to health of the animal, so the reintroduction of harmless prokaryotes is vital to restore the microbiome and bring the animal back to full health.
+ Would have killed cellulose-digesting prokaryotes (in plant cell walls)
Cow then couldn’t eat and might die
So, reintroducing prokaryotes = cow lives

Question 6

Proteins, which have diverse functions in a cell, are all polymers of the same kinds of monomers—amino acids. Discuss how the structure of amino acids allows this one type of polymer to perform so many functions.

Answer 6

The R group provides additional chemical character to an amino acid (gives traits like polarity, ionic or basic etc).
Gives high level of chemical variation on protein surfaces, leading to specialized interactions.

Question 7

1. Explain why the structure of a protein and its function are intimately interconnected. Describe the forces that hold proteins in their functional conformation.

Answer 7

Protein function dependent on tertiary structure.
Folding allows highly specific function.
Enzymes is a good example.

Tertiary structure is ultimately determined by primary structure - sequence of amino acids on polypeptide chain.
Hydrogen bonds between nonadjacent (not next to each other – near each other & make alpha helixes and beta pleats/sheets)
This structure then folded into tertiary structure (3D)
Folds determined by intermolecular interactions between R groups (amino acid specific side chains).
R group attractions include:
Hydrogen bonding
Dipole dipole
Ionic
Disulphide bridges
LD
LDS

Question 8

Given that the function of egg yolk is to nourish and support the developing chick, explain why egg yolks are so high in fat, protein, and cholesterol.

Answer 8

Fat = energy source
More efficient than glucose over long time period
Slow releasing = more efficient helping chick grow over 21 days

Proteins = essential for building cells, cell differentiation and growth (as amino acids are made of proteins, which are essential for life functions, so without them, could not make cellular proteins and therefore would not grow)

Cholesterol = cellular structure
Plasma membrane
Precursor for chemicals and hormones (e.g. androgens) and vitamins (A, D).
Essential for development and growth.