Lab Midterm Review

Fill-in-the-blank flashcards covering core concepts from molecular biology, genetics, lab techniques, and inheritance patterns for exam review.

The Central Dogma of biology describes the flow of genetic information from DNA to RNA to __.

Proteins

During transcription, RNA polymerase first binds to the __ region upstream of a gene.

promoter

The mRNA produced looks identical to the DNA coding strand except that __ replaces thymine (T).

uracil (U)

Transcription proceeds in three stages: Initiation, __, and Termination.

Elongation

In eukaryotes, non-coding regions called __ are removed from pre-mRNA inside the nucleus.

introns

Translation begins when the ribosome recognizes the start codon __ (methionine).

AUG

Within the ribosome, tRNA molecules move sequentially through the _, P, and E sites.

A

Translation stops when the ribosome encounters one of three stop codons: UAA, UAG, or _.

UGA

A straight chain of amino acids represents the __ level of protein structure.

primary

α-helices and β-sheets are formed at the __ level of protein structure.

secondary

All amino acids contain C, H, O, and N, but the side chains of cysteine and methionine additionally contain the element __.

sulfur (S)

In electrophoresis, negatively charged molecules migrate toward the __ electrode.

positive

A centrifuge must be __ so that samples are distributed evenly before spinning.

balanced

A __ is the presence of two or more distinct forms of a trait or DNA sequence in a population.

polymorphism

Alu polymorphisms arise via a “jumping gene” mechanism called __.

retrotransposition

The Meselson–Stahl experiment showed that DNA replication is __, with each daughter helix containing one old and one new strand.

semi-conservative

PCR cycles consist of three steps in order: Denaturation, __, and Elongation.

Annealing

The theoretical number of DNA molecules after n PCR cycles equals __ × initial molecules.

2^n

During PCR denaturation, DNA strands separate at approximately __ °C.

94–98

Annealing temperature is set about __ °C below the primer’s melting temperature.

5

Taq polymerase, used in PCR, was isolated from the thermophile Thermus __.

aquaticus

To dilute solutions in lab, the formula __ is used.

C1 V1 = C2 V2

Preparing 100 mL of 50 % ethanol from 100 % stock requires __ mL of pure ethanol.

50

A 5 % KCl solution made with 400 mL of water needs __ g of KCl.

20

Sickle Cell Anemia results from a single-nucleotide __ mutation in the HBB gene.

missense

In Sickle Cell disease, an A→T change converts glutamic acid to __ at position six of β-globin.

valine

Heterozygotes for the sickle-cell trait are protected against __, illustrating balanced selection.

malaria

In __ inheritance, both alleles in a heterozygote are expressed simultaneously.

codominant

CRISPR stands for Clustered Regularly Interspaced Short __ Repeats.

Palindromic

One major challenge of CRISPR/Cas9 technology is unintended __ effects.

off-target

Therapies for hemoglobinopathies use CRISPR to disrupt BCL11A, increasing production of __ hemoglobin (HbF).

fetal

Changes in DNA sequence are called __ and may be beneficial, neutral, or harmful.

mutations

Point mutations are classified as silent, missense, or __ (premature stop).

nonsense

__ mays (corn) has 10 chromosomes and produces both male and female flowers.

Zea

Gregor Mendel discovered dominant and recessive inheritance patterns using garden __.

peas

The offspring of two true-breeding parents form the __ generation.

F1 (first filial)

Punnett Squares are diagrams used to __ offspring genotypes and phenotypes.

predict

A dihybrid cross of two heterozygotes typically yields a __:1 phenotype ratio for each dominant to recessive trait.

3

For independent events in sequence, probabilities are multiplied; the chance of a boy and then a girl is __ %.

25

For "either-or" situations, probabilities are added; 12.5 % + 12.5 % equals __ %.

25

The coefficients 1-4-6-4-1 arise from the binomial expansion of (a+b)__.

^4

A χ² value yielding p < 0.05 leads us to __ the null hypothesis.

reject

Degrees of Freedom equal the number of categories minus __.

one

A __ organism has had its DNA altered through genetic engineering.

genetically modified (GMO)

Members of the fungal phylum __ produce sexual spores inside an ascus.

Ascomycota

During the cell cycle, DNA replication occurs in the __ phase.

S

Mitosis produces two genetically __ daughter cells.

identical

Meiosis reduces chromosome number from 2n to n and yields __ haploid gametes.

four

Homologous chromosomes undergo crossing over during __ of Meiosis I.

Prophase I

The gene __ on the Y chromosome is critical for male sex determination.

SRY

Turner Syndrome results from a genotype of __.

XO

Because males possess only one X chromosome, X-linked recessive traits affect them more often; females mitigate effects through __ of one X.

X-inactivation