General Biology: Cell Cycle, Genetics, and Molecular Biology Review

What are the stages present in both G1 and prophase?

I and III: DNA and centromeres.

At what stage of the cell cycle does the ploidy change?

Ploidy does not change during the cell cycle.

What correctly describes both binary fission and the cell cycle?

II and III: Genetic material duplicates and daughter cells are identical to parent cell.

Which statements are true regarding homologous chromosomes?

I and II: They form tetrads during meiosis I and replicate during the S phase.

How does mitosis compare in haploid and diploid cells?

In haploid cells, one set of chromosomes ends up in each daughter cell, but in diploid cells, two sets end up.

If a cell has 18 pairs of homologous chromosomes, how many chromosomes and chromatids does it have after S phase?

36 chromosomes and 72 chromatids.

What is the correct sequence of the cell cycle starting with S phase?

III → IV → I → V → II.

During which phase of meiosis is ploidy reduced?

First meiotic division (specifically Anaphase I).

How many pairs of homologous chromosomes does an organism with a diploid number of 2n=16 have?

8 pairs.

What is the ploidy and number of chromosomes in daughter cells at the end of prophase II after meiosis?

Haploid, 13.

Which diagram depicts a cell in metaphase I?

I only: Shows homologous pairs lined up.

What is the correct sequence in the life cycle of an animal?

III → IV → V → I → II.

What characteristics describe both asexual and sexual reproduction?

I and IV: Genetic material is transmitted to offspring and chromosome number does not change.

What happens if proteins in the synaptonemal complex are not produced?

The patient's cells would be unable to undergo normal metaphase I.

What best describes the ultimate outcome of meiosis?

1 parent cell divides into 4 genetically unique daughter cells.

What percentage of offspring will be homozygous recessive for both traits if a TTYY female is mated with a ttyy male?

0%.

What is the outcome of a male and female bird producing an offspring that is homozygous recessive for wing color?

The offspring will be ww.

What is the genotype of the female parent if the male parent is homozygous recessive ($ww$) and they produce an offspring that is homozygous recessive for wing color ($ww$)?

The female parent could be heterozygous ($Ww$) or homozygous recessive ($ww$).

What is the probability that a human couple's first child is a girl and their second child is a boy?

0.25

What are the parental genotypes of a guinea pig with degenerative myelopathy, an autosomal recessive disease ($d$)?

The mother is heterozygous and the father is homozygous recessive.

Which concepts in genetics does Mendel's theory of particulate inheritance explain?

II and IV (Dominant alleles mask recessive alleles and 2 alleles for a character segregate during meiosis).

Which statements are TRUE based on a Punnett square of a $Pp \times Pp$ cross?

I and III (Monohybrid cross is true and both parents are heterozygous).

Which statements are TRUE regarding dominant and recessive alleles?

I, II, and IV (Dominant and recessive alleles can be found in the same individual, dominant alleles mask recessive alleles, and recessive alleles are expressed only if the dominant allele is absent).

What type of inheritance pattern is suggested if parents do not express a trait but 25% of daughters and 25% of sons express it?

Mendelian/Autosomal inheritance.

What are the TRUE comparisons between the theory of particulate inheritance and chromosomal inheritance?

I, II, and III (Both ideas include the segregation of alleles, genes on the same chromosome do not independently assort, and all genes assort independently according to particulate inheritance).

Which characteristics describe BOTH pea plants and fruit flies?

III and IV (Short generation times and clearly identifiable traits).

What is the central finding of Morgan that differs from Mendel's conclusions?

Genes move on chromosomes, not as individual units.

What does it mean for an animal with sex chromosomes XY to be hemizygous for certain characters?

Every allele on the X chromosome is expressed.

Which ancestor could be the source of a Y-linked disorder in a man?

Paternal grandfather (his father's father).

Which statements are TRUE regarding a replication bubble diagram?

I and III (5' end of the molecule and elongation only occurs here).

At which stage of the cell cycle do sister chromatids form?

S-phase of interphase.

What occurs during the S-phase of interphase?

DNA replication occurs, duplicating each chromosome to form two identical sister chromatids.

How do nitrogenous bases in dsDNA interact?

They form hydrogen bonds with complementary nitrogenous bases.

What are the functions of DNA polymerase?

It catalyzes the formation of phosphodiester bonds and synthesizes a strand complementary to the parent strand.

Which scientists contributed to the understanding that DNA contains heredity information?

Rosalind Franklin, Watson and Crick, Hershey and Chase, and Griffith.

What is the complementary DNA strand for 5' A A T G G C T A 3'?

3' T T A C C G A T 5'.

What is the function of topoisomerase during DNA replication?

It breaks and rejoins linkages in the DNA backbone to relieve supercoiling.

If 20% of DNA nucleotides are C, what percentage are A?

30% of the nucleotides are A.

What occurs at the initiation of transcription?

RNA polymerase attaches to the promoter.

What are introns?

Non-coding regions that are removed from DNA sequences.

During which process is information in DNA used to make RNA?

Transcription.

What is used as a template to synthesize specific mRNA?

DNA.

What effect does a competitive inhibitor have on nucleoside triphosphates?

It affects DNA polymerase, RNA polymerase, and ribosomes.

What are the true statements comparing mRNA and tRNA?

Both are single-stranded and involved in translation.

What is the correct sequence of translation?

II → V → I → III → IV.

What is an operon?

A set of genes controlled as a unit.

Which steps in eukaryotic gene expression require a codon?

Translation termination and translation elongation.

Which processes occur in both prokaryotic and eukaryotic cells?

Translation, replication, and transcription.

Which of the following contribute to gene regulation in prokaryotes and eukaryotes?

Promoters

What is a characteristic of constitutive genes?

They are constantly transcribed.

What occurs in an E. coli cell living in a medium with no glucose and high lactose?

Active CAP bound to the promoter and high levels of lac operon transcription.

Compare the promoter and operator of the lac operon. Which statements are true?

Neither is transcribed; both function as binding sites.

What is the effect of a mutation that prevents methylation of DNA?

Higher rate of transcription.

What happens if a drug inhibits transcription factors of a eukaryotic cell?

Binding of RNA polymerase to the promoter will be impaired.

What is true regarding gel electrophoresis?

DNA migration is due to its negative charge.

What method is used to amplify a small sample of DNA?

PCR.

What occurs in a cell during DNA replication but not in PCR?

Unwinding of the DNA helix by helicase.

Which nucleotides are involved in DNA replication?

Deoxyribonucleotide.

Correctly sequence the process of dideoxy chain termination.

V → II → III → I → IV.

What is the dideoxy chain termination method used for?

To sequence a fragment of DNA.

What is the effect of the absence of ddATP in a sequencing reaction?

The spectrogram will not show sequences ending in adenine.

For an individual to express a recessive mutant trait, what must they have?

They must have two mutant alleles.

During which stages of meiosis can nondisjunction result in aneuploidy?

Anaphase I and Anaphase II.

What are true statements about amniocentesis and chorionic villus sampling (CVS)?

Amniocentesis collects fetal cells from the amniotic fluid; CVS collects cells from the placenta.

What is required for DNA replication, transcription, PCR, and dideoxy chain termination sequencing?

Complementary base pairing.

Which indicates a trisomy in a human?

A somatic cell with 45 autosomes + XY.

What types of human genetic disorders can be caused by nondisjunction?

Monosomy and aneuploidy.

What factors make analysis of human genetics difficult?

Few offspring, unethical to experiment on humans, long generation time.