Introduction to biomolecules and the cell

Question 1

Identify the basic components of the cell.

Answer 1

Nucleus, nucleolus, chromatin, nuclear pore, nuclear envelope, golgi body, centriole, ribosome, smooth ER, rough ER, lysosome, cytoplasm, mitochondrion, plasma membrane

Question 2

Describe the basic details of the four major classes of biological molecules which include:
Proteins, Lipids, Carbohydrates, nucleic acids (DNA and RNA)

Answer 2

Proteins: N terminus, C-terminus, monomers of amino acids, which make up the primary sequence of the mature protein
Lipids: insoluble in water, hydrophobic or amphipathic, hydrophobic carbon tails
Carbohydrates: sugars, glycogen, starches. Cm(H20)n. monosaccharide unit is a single sugar
Nucleic acids: DNA/RNA, monomers are nucleotides. RNA is a ‘copy’ of the DNA code that allows it to be expressed.

Question 3

Describe dominant and recessive modes of inheritance

Answer 3

Dominant Inheritance: Presents phenotypically if only one copy of the dominant gene is present.
Recessive inheritance: an individual can be a carrier with one recessive gene but is only expressed when both genes are affected.

Question 4

Describe the key structural features of DNA.

Answer 4

Sugar-phosphate backbone and a nitrogenous base. Base pairs AG are purines, TC are pyrimidines. G-C bond forms 3 hydrogen bonds.

Question 5

Explain the functions of nucleotides.

Answer 5

Nucleotides are the building blocks of genetic material that form DNA and RNA.

Question 6

Explain DNA replication.

Answer 6

Section of packaged DNA needs to be unwound, primase (RNA primer) synthesized, DNA polymerase binds and replicates, is proofread by 3’-5’ exonuclease activity, each parent strand is template for a new daughter strand (semiconservative). Complementary base pairing occurs in 5’-3’ direction, reads 3’-5’

Question 7

Describe the structure of the gene.

Answer 7

-Promoter: RNA pol binds to DNA
-Coding region: Codes for the codons for mRNA
-Terminator: ends transcription

Question 8

Briefly explain transcription, translation and protein synthesis.

Answer 8

Transcription: 3 steps; initiation, elongation, termination (DNA to mRNA)

Translation: ribosome reads mRNA in 5’ to 3’ direction, new protein grows from n-terminus to c-terminus. same 3 steps as transcription

Protein synthesis: When ribosome reaches stop codon on mRNA it releases newly synthesized polypeptide