BIO practice exam 2

What makes the genetic code redundant or degenerate?

Each amino acid can be coded by multiple codons.

What did Friedrich Miescher observe the 'nuclein' to be rich in?

Phosphorus.

What is needed for mRNA binding to the ribosome during translation?

The mRNA binds to the small ribosomal subunit.

During translation, what happens when a stop codon is encountered?

The release factor aids in the hydrolysis of the newly synthesized polypeptide from the ribosome.

What is true about cells in the G0 phase?

The cells are not actively dividing.

Is mitosis required for wound healing in non-growing organisms?

Yes, it is required.

What is the role of a centriole?

The statement that it is the constricted point where sister chromatids are attached is false.

What does a karyotype represent?

An image of an individual's complete collection of chromosomes.

How many RNA primers does the leading strand need during DNA replication?

One RNA primer.

Which enzyme relieves torsional stress during DNA replication?

Topoisomerase.

What organelle is involved in forming spindle fibers during mitosis?

Centrosome.

What is the name of the strand being transcribed in a double-stranded DNA?

Template strand.

How are the somatic cells produced by mitosis described?

They are genetically identical and diploid.

What is added to the 3' end of mRNA during post-transcriptional processing?

Poly-A tail.

To which organelle are ribosomes often attached for polypeptide modifications?

Endoplasmic reticulum (ER).

Are transcription and translation spatially separated in eukaryotes?

Yes, they do not occur simultaneously.

What is the 10nm structure referred to in DNA packaging?

Beads on a string structure.

Which organism did Frederick Griffith use in his transformation experiments?

Streptococcus pneumoniae.

Which organisms require the protein FtsZ during binary fission?

Prokaryotes.

What checkpoint checks if spindle fibers are attached to the kinetochore?

M checkpoint.

What model of DNA replication did Meselson and Stahl demonstrate?

Semi-conservative model.

During which phase of the cell cycle does DNA replication occur?

It does not occur during G2 phase.

Which complex is involved in splicing introns and joining exons?

Spliceosome.

What is the order in which mRNA is synthesized?

RNA polymerase initiates synthesis at the promoter, elongates the strand, and releases the transcript upon termination.

Is the 'one gene one enzyme' hypothesis still fully accurate?

No, it has been modified.

In which phase does the nuclear envelope begin to break down during mitosis?

Prophase.

How many chromosomes does a normal diploid human cell have?

46 chromosomes (23 pairs).

Which end of the growing DNA strand can DNA Polymerase add nucleotides to?

3' end.

What is NOT true about ribosomes?

They are essential for mRNA synthesis.

What term describes DNA that is accessible for gene expression?

Euchromatin.

Which enzyme joins Okazaki fragments during DNA replication?

DNA ligase.

What enzyme is needed for polymerase chain reaction (PCR)?

DNA polymerase.

In which direction is DNA synthesized?

5' to 3' direction.

What is the first amino acid in polypeptide synthesis?

Methionine.

What enzyme prevents gene erosion?

Telomerase.

Are HeLa cells obtained ethically?

False.

How is mRNA read during protein synthesis?

As codons, each made of 3 nucleotides.

What structural feature was shown in 'Photo 51' by Rosalind Franklin?

The helical structure of DNA.

Does a cleavage furrow form during cytokinesis in plant cells?

False.

What nutrients were missing in the minimal medium used by Beadle and Tatum?

Vitamins.

What protein develops during prometaphase in mitosis?

Kinetochore protein.