BIO 2.9-2.10 End of Quiz

A molecule of DNA contains two polymer strands called , made by bonding together many monomers called .

Polynucleotides; nucleotides.

Name the three parts of every nucleotide.

Sugar, phosphate, nitrogenous base.

List these terms in order of size from largest to smallest: chromosome, codon, gene, nucleotide.

Chromosome → Gene → Codon → Nucleotide.

How much radioactivity will each daughter DNA molecule contain after replication of a radioactive DNA molecule?

One radioactive strand and one nonradioactive strand.

The nucleotide sequence of a DNA codon is GTA. What is the mRNA codon?

CAU.

What is the tRNA anticodon that pairs with this mRNA codon?

GUA.

What amino acid is attached to this tRNA?

Histidine.

Describe transcription and translation of a gene into a protein.

DNA → mRNA by RNA polymerase; ribosome reads mRNA codons; tRNA brings amino acids; peptide bonds form until stop codon.

Which molecules are involved in translation?

Ribosomes and tRNA.

Which molecules are involved in DNA replication?

DNA polymerases.

Which molecule is involved in transcription?

RNA polymerase.

Which molecule is involved in both transcription and translation?

mRNA.

A mutation has no effect on the polypeptide. Which type is this?

Substitution (silent mutation).

A phage with protein coat of A and DNA of B infects a bacterium. The phages produced will have?

Protein and DNA of B.

How do some viruses reproduce without DNA?

They use RNA genomes to replicate and make proteins.

HIV requires an enzyme to convert RNA to DNA. Name it.

Reverse transcriptase.

Why is reverse transcriptase a good drug target?

Humans don’t have it; drugs block virus without harming host.

Nearly all organisms share the same genetic code. What theme does this illustrate?

Evolution.

The shape of tRNA relates to which theme?

Structure-function relationship.

Genes carry instructions for RNA/protein. Theme?

Information flow.

A single chromosome cell is placed in radioactive phosphate and divides twice. Describe DNA in four cells.

Two cells: one radioactive + one normal strand; two cells: both strands radioactive.

Did Zika, Dengue, and Chikungunya follow the same pattern?

No; infection peaks differed.

Should genes or gene products be patented?

Genes: no; new uses/technologies: yes.

Why is tanning dangerous?

UV damages DNA → mutations → skin cancer/premature aging.

Should children get flu vaccines before school?

Yes.

Should hospital workers get flu vaccines?

Yes.

Alleles of homologous chromosomes separate independently during gamete formation. Which Mendel’s law is this?

Law of Independent Assortment.

Alleles segregate during gamete formation; fertilization restores pairs. Which law?

Law of Segregation.

Edward is heterozygous (Ss) for sickle-cell trait. Where are the alleles located?

On homologous chromosomes.

Whether an allele is dominant or recessive depends on?

Which allele determines phenotype when both are present.

Two fruit flies with red eyes are crossed; offspring includes red and ruby eyes. Gene type and allele for ruby eyes?

Sex-linked; recessive.

All offspring of white hen × black rooster are gray. Inheritance pattern?

Incomplete dominance.

Man has type B blood, woman type A. Possible children’s phenotypes?

A, B, AB, or O.

Duchenne muscular dystrophy is sex-linked recessive. Probability second child has disease?

25%.

Adult height is partially hereditary but shows a range. Which extension of Mendel’s model explains this?

Polygenic inheritance.

Purebred brown × purebred white mice → all brown F₁. F₂: what fraction are brown?

¾ (75%).

How can you determine if a brown F₂ mouse is homozygous or heterozygous?

Testcross with white mouse; if white offspring appear → heterozygous.

Tim and Jan both have freckles (dominant), son doesn’t. How is this possible? Probability next 2 children have freckles?

Parents Ff × Ff; 9/16 probability.

Mack and Toni heterozygous for hypercholesterolemia (Hh × Hh). Fraction of children with moderate levels?

½ (Hh).

Probability their child has severe hypercholesterolemia (hh)?

¼.

Why was Henry VIII wrong to blame wives for producing daughters?

Male determines sex; sperm carries X or Y.

Both parents normal, son has hemophilia. Fraction of children with hemophilia? Fraction carriers?

Sons: ½ affected; daughters: ½ carriers.

Heather has red-green colorblindness. Why did her professor know her father must be colorblind?

Female inherits one X from father; he must have given the affected X.