Exam 4 Review: DNA, Replication, P. Synthesis, Cell Cycle and M.

James Watson and Francis Crick, with the work of Rosalind Franklin's xray crystallography imaging determened the structure of DNA. They called its "twisted lader" form a...

• deoxyribonucleic acid

• deoxyribonuclear acid

• double helix

• twisted helix

The process by which DNA makes a copy of itself is called:

• dna synthesis

• dna replication

• transcription

• translation

A gene is...

• a segment of dna that codes for a protein

• a set of homologous chromosomes

• a molecule within dna

• a type of pants

A nucleotide made of these three parts: a phosphate group, and ribose sugar, and a adenine would be what?

• a RNA nucleotide

• a DNA nucleotide

Answer explanation

Because the nucleotide is made with a ribose sugar and not a deoxyribose sugar, then it is an RNA nucleotide.

The "rungs" of the DNA ladder are made of...

• phosphates and hydrogens

• glucose and sugar

• sugars and phosphates

• base pairs

Answer explanation

The rungs of the DNA ladder are made of nitrogenous base pairs, bonded by hydrogen bonds.

Three nucleotides code for:

• 1 amino acid

• 3 amino acids

• 1 protein

• 3 proteins

Answer explanation

A sequence of 3 mRNA nucleotides makes a codon, which translates into an amino acid.

DNA is called the "blueprint of life" because...

• It is a blue color

• It is like a fingerprint

• It contains the plans for building an organism

• It can relay messages to other molecules

True or False: For DNA and RNA complementary base pairing, adenine always pairs to thymine, and guanine always pairs to cytosine.

• True

• False

Answer explanation

DNA has the nitrogenous base thymine. RNA does not, and has uracil in its place. For complementary base pairig of DNA nucleotides, A always pairs to T and C always pairs to G. In RNA, C still pairs to G, but A pairs to U instead.

If a DNA sample contains 23 percent adenine, how much cytosine does it contain?

• 23%

• 54%

• 22%

• 27%

Answer explanation

Because the DNA sample contains 23% adenine, then it also contains 23% thymine. This leave 54 total % remaining between cytosine and guanine. Divide 54% by 2, and you get 27%, which is the amount of cytosine and guanine present in the sample. This is known as Chargaff's rule.

Rosalind Franklin used a(n) __________ to photograph DNA. Her work was used by Francis and Crick to discover the structure of DNA as the double helix.

• xray

• light microscope

• electron microscope

• glasses

Answer explanation

The image that she produced was done with a process called x-ray crystallography.