AGRI 376 Genetics Exam Ultimate Study Guide

Transmission Genetics focuses on __________ and the mechanisms through which traits are passed from parents to offspring across generations.

the basic principles of heredity

The complete set of specific alleles an organism possesses is referred to as its __________.

genotype

The observable physical manifestation of an organism's genotype, produced via interaction with the environment, is called __________.

phenotype

The __________ is a fundamental physical and functional unit of heredity composed of a specific sequence of nucleotides.

gene

An allele that masks or suppresses the phenotypic expression of an alternative recessive allele in the heterozygous condition is known as a __________.

dominant allele

The synthesis of single-stranded RNA molecules from an enzymatic reading of a complementary DNA template strand, occurring within the nucleus, is called __________.

transcription

In DNA replication, the __________ strand is synthesized continuously in the direction of the replication fork.

leading

DNA __________ catalyzes the formation of a covalent phosphodiester bond between adjacent nucleotides, sealing single-strand nicks in the sugar-phosphate backbone.

ligase

Telomerase is a specialized ribonucleoprotein enzyme that adds repetitive sequences to the __________ of chromosomes to maintain length and integrity.

ends

The __________ matrix is a statistical framework used to assess whether observed phenotypic ratios differ from theoretical Mendelian expectations.

Chi-Square ($\chi^2$)

Nitrogenous bases containing a double-ring structure, specifically adenine and guanine, are classified as __.

purines

Nitrogenous bases containing a single six-membered ring, including cytosine, thymine, and uracil, are classified as __.

pyrimidines

Adjacent nucleotides in a single polynucleotide strand are covalently joined by a __ bond linking a 5'-phosphate group to a 3'-hydroxyl group.

phosphodiester

According to Chargaff's rules, double-stranded DNA contains an equimolar concentration of adenine to thymine and cytosine to __.

guanine

During DNA replication, the enzyme __ unwinds the parental DNA duplex by disrupting hydrogen bonds ahead of the replication fork.

helicase

Tetrameric proteins that attach to single-stranded DNA to prevent reannealing during replication are called __.

single-stranded binding proteins

The enzyme that synthesizes short complementary RNA sequences providing the 3'-OH end required for DNA elongation is __.

primase

In prokaryotes, the primary catalytic enzyme responsible for 5' to 3' processive chain elongation is DNA polymerase __.

III

The enzyme that excises RNA primers with its 5' to 3' exonuclease activity and fills the resulting gaps with DNA is DNA polymerase __.

I

Short, discontinuously synthesized DNA segments generated along the lagging strand during replication are known as __.

Okazaki fragments

In prokaryotic transcription initiation, the __ subunit of the RNA polymerase holoenzyme is required to recognize and bind the promoter.

sigma ($\sigma$)

During eukaryotic pre-mRNA processing, the 5' terminus is stabilized against degradation by the enzymatic addition of a __ cap.

7-methylguanosine

Non-coding intervening sequences removed from pre-mRNA transcripts prior to nuclear export are designated as __.

introns

Coding segments of eukaryotic mRNA that are joined together after intron excision to form mature transcripts are called __.

exons

A specific triplet sequence of ribonucleotides along mRNA specifying an amino acid or translation stop signal is termed a __.

codon

The three-nucleotide sequence on a transfer RNA molecule that base-pairs with a complementary mRNA triplet during translation is the __.

anticodon

The enzyme family responsible for charging tRNA molecules by covalently linking each specific tRNA to its cognate amino acid is __.

aminoacyl-tRNA synthetase

During elongation in translation, incoming charged aminoacyl-tRNAs initially bind at the ribosome's __ site.

A

Peptide bond synthesis between an incoming amino acid and the growing peptidyl chain is catalyzed by __ within the large ribosomal subunit.

peptidyl transferase

A point mutation that substitutes a purine for another purine (or a pyrimidine for another pyrimidine) is classified as a __.

transition mutation

A base substitution that replaces a purine with a pyrimidine (or vice versa) is classified as a __.

transversion mutation

A base substitution that alters a codon but does not change the amino acid sequence of the encoded polypeptide is a __ mutation.

silent

A point mutation that converts a codon specifying an amino acid into a premature stop codon is known as a __ mutation.

nonsense

Mutations caused by insertions or deletions of nucleotides in numbers not divisible by three, altering downstream codon reading, are called __ mutations.

frameshift

Sickle cell anemia is caused by a point mutation in the hemoglobin gene converting a GAG codon to GTG, replacing glutamic acid with __.

valine

DNA sequences capable of excising themselves and inserting into new genomic positions, initially described as jumping genes, are __.

transposable elements

The cellular repair mechanism that identifies bulky DNA lesions, uses uvr proteins to excise the damaged oligomer, and replaces it using DNA polymerase I and ligase is __.

nucleotide-excision repair

The failure of homologous chromosomes to separate during meiosis I, or sister chromatids to separate in meiosis II, is referred to as __.

nondisjunction

Cri-du-chat syndrome is an abnormality resulting from a terminal deletion of the short arm of chromosome __.

5

A structural chromosomal aberration where a segment detaches, rotates 180 degrees, and reinserts into the same chromosome is an __.

inversion

A chromosomal mutation characterized by the exchange or transfer of a segment between two non-homologous chromosomes is a __.

translocation

A sex chromosome aneuploidy characterized by a 47,XXY karyotype in phenotypic males is __ syndrome.

Klinefelter

A sex chromosome aneuploidy in females characterized by a 45,X karyotype with monosomy of the X chromosome is __ syndrome.

Turner

A base substitution that alters a codon to specify a chemically similar amino acid, resulting in minimal change to protein structure, is a __ mutation.

conservative

A chromosomal mutation in which a specific segment of DNA or gene sequence is repeated is a __ mutation.

duplication

A chromosomal condition caused by nondisjunction that results in three copies of chromosome 21 is __ syndrome.

Down

A fatal disorder resulting from a mutation in the HEXA gene on chromosome 15 that causes a deficiency of hexosaminidase-A is __ disease.

Tay-Sachs

During DNA replication, the enzyme that relieves torsional strain and supercoiling ahead of the replication fork is DNA __.

gyrase

During eukaryotic pre-mRNA processing, a non-templated sequence of adenine nucleotides added to the cleaved 3' end is the __.

poly-A tail

During translational elongation, the ribosomal site that holds the tRNA carrying the growing polypeptide chain is the __ site.

P

A bacterial mRNA transcript that carries the coding sequences for multiple structural genes is designated as __ mRNA.

polycistronic

A complex comprising multiple ribosomes simultaneously translating a single mRNA molecule is termed a __.

polysome

The specific nucleotide sequence along a chromosome where replication initiates and the replication bubble opens is the __.

origin of replication

The reciprocal exchange of genetic material between non-sister chromatids of homologous chromosomes during prophase I of meiosis is __.

crossing over

One of two or more alternative versions of a gene located at a specific position on a chromosome is an __.

allele