Final Exam Practice Test Questions

Vocabulary flashcards for genetics exam review.

G2 Phase Malfunction

If a cell experiences a malfunction during the G2 phase, potential outcomes include improper chromosome segregation, delayed cytokinesis, and excessive cell growth affecting subsequent cell division.

Gametes

are produced by meiosis, a process of cell division that results in four daughter cells each with half the number of chromosomes of the parent cell.

Tetrads in Meiosis

Tetrads are significant in meiosis as they allow for genetic recombination and ensure proper segregation of chromosomes.

Mutant Allele

A mutant allele leading to a nonfunctional protein may cause the organism to exhibit a phenotype that is different from the wild-type.

RNA vs DNA

RNA differs from DNA in that RNA strands have 5' and 3' ends; RNA has a hydroxyl (OH) group attached to the 2' carbon of the sugar; and RNA contains uracil in place of cytosine.

Bivalents in Meiosis

Bivalents facilitate genetic recombination and ensure proper segregation of chromosomes, contributing to genetic diversity.

Sister Chromatids Creation

Sister chromatids are created during DNA replication when a chromosome is duplicated.

Homozygous Genotypes

Homozygous dominant genotypes express the dominant trait, while homozygous recessive genotypes express the recessive trait, influencing phenotypic outcomes.

Nondisjunction

Nondisjunction can result in trisomy (3 copies of a chromosome), extra sex chromosomes, and monosomy (1 copy of a chromosome).

G0 Phase

In the G0 phase of the cell cycle, a cell is temporarily not going through the cell cycle or never dividing again and may accumulate molecular changes.

Breaking Cohesion Proteins

Breaking cohesion proteins allows sister chromatids to separate and move to opposite poles, ensuring proper distribution of genetic material.

Sister Chromatids

Sister chromatids are identical or nearly identical copies of each chromosome that are attached in the middle.

Gametogenesis

The term gametogenesis refers to the process of forming sex cells.

Gene Duplication

If a gene undergoes duplication and one copy mutates, there organism may benefit from a novel function or experience redundancy.

Heterozygous Condition

If an organism has two different alleles for a particular gene, this condition is called heterozygous; it may result in a mix of traits or dominance of one trait over another.

Mitosis Role

Mitosis is essential for growth and repair as it produces identical daughter cells that replace damaged or lost cells.

Centromere Role

The role of the centromere in sister chromatids is to join sister chromatids together.

Nonessential Gene Mutation

If a mutation occurs in a nonessential gene, it may provide a beneficial trait or have no significant impact on an organism's fitness.

Homozygous Dominant

A homozygous dominant genotype is two copies of the dominant allele.

G2 phase prepare

The G2 phase of the cell cycle prepares for meiosis.

Sister Chromatids Relationship

Sister chromatids are identical copies of a chromosome that separate during cell division to ensure each daughter cell receives an identical set of chromosomes.

Random Distribution

The term used to describe the random distribution of chromosomes during meiosis is independent assortment.

Chromosome Number

The chromosome number at the start of meiosis I in humans is 46 (2n).

Independent Assortment

Independent assortment leads to genetic variation by randomly distributing maternal and paternal chromosomes into gametes.

Spindle Fibers Function

Spindle fibers facilitate the movement of chromosomes by attaching to kinetochores during mitosis.

Gene Duplication Definition

Gene duplication is the process where a segment of DNA is duplicated.

Spindle Apparatus Disruption

If a mutation disrupts the formation of the spindle apparatus during diakinesis, the gametes may have an abnormal number of chromosomes.

Bivalent Definition

A bivalent in meiosis is a structure formed during meiosis where homologous chromosomes align and are paired together, consisting of two pairs of sister chromatids.

Cohesion Proteins Primary Function

The primary function of cohesion proteins is to hold sister chromatids together until they are separated during anaphase.

Cytokinesis Definition

Cytokinesis is the division of the cytoplasm following mitosis that forms two daughter cells.

Position Effect

The position effect can alter gene regulation by changing the proximity to regulatory elements, leading to increased or decreased expression.

Spindle Fibers Purpose

The spindle fibers aid in cell division by separating chromosomes.

Synaptonemal Complex Dissociation

The dissociation of the synaptonemal complex allows homologous chromosomes to begin separating, which is crucial for proper chromosome segregation.

Essential Genes

Essential genes are crucial for survival as they produce proteins that perform vital cellular functions.

Epistasis Affect Phenotypic Traits

Epistasis can alter the expression of phenotypic traits by modifying how one gene interacts with others, leading to variations in traits.

Meiosis I differ from Meiosis II

Chromosome number decreases by half as a result of meiosis I, but not as a result of meiosis II.

Centromere

The centromere is a region of the chromosome where the sister chromatids join.

Independent Assortment contributes

Independent assortment contributes to the genetic diversity of gametes by influencing the combination of maternal and paternal chromosomes in each gamete

RNA and DNA structure

All of the above : RNA has a 5 ring ribose sugar while DNA has a deoxyribose sugar, RNA has uracil in place of thymine , most RNA are single stranded

Epistasis

Epistasis occurs when the alleles of one gene mask the effects of alleles from another gene at a different locus.

Sister Chromatids

Sister chromatids are two identical copies of a chromosome

Chromosome During Mitosis

During mitosis, the number of chromosomes remains the same as compared to the original mother cell.

Sister Chromatids

Sister chromatids: Two identical copies of a chromosome

Mitosis Failure to seperate

One daughter cell would receive an extra chromosome while the other would be missing that chromosome.

euploidy , Down Syndrome are are examples

Down Syndrome is an example of Aneuploidy.

genetic variation

Alleles contributes to genetic variation by providing different versions of genes that can lead to diverse traits.

transposable elements

The two main classifications of transposable elements are DNA transposons and retrotransposons.

chromosomes at the metaphase plate during meiosis 1

A pair of duplicated chromosomes at the metaphase plate during meiosis 1 is known as a Bivalent.

mutation occurs…

If a mutation occurs that prevents the formation of bivalents during meiosis, the resulting gametes may have an abnormal number of chromosomes due to improper segregation.

paracentric inversion

If a paracentric inversion occurs in a gene responsible for a specific trait, it could alter the expression of the trait associated with that gene.

G0 phase characteristic

The primary characteristic of cells in the G0 phase of the cell cycle is that cells are temporarily not advancing through the cell cycle or are terminally differentiated and will never divide.

Mitosis best described

Mitosis is a cell division process that results in two identical daughter cells with the same chromosome number as the parent cell.

random alignment of bivalents increase?

The random alignment of bivalents increases genetic diversity through independent assortment.

nondisjunction occurs during meiosis in humans, what genetic condition?

Down syndrome

metaphase plate significance

The metaphase plate is crucial for the accurate alignment of chromosomes, which is essential for their proper segregation into daughter cells.

RNA and DNA

RNA has ribose sugar, uracil instead of thymine, and is usually single-stranded, while DNA has deoxyribose sugar and is double-stranded.

Function of centromeres

Centromeres are they are essential for segregation of chromosomes to daughter cells.

Transposable elements (TEs)?

DNA sequences that are multiple copies of the same gene.

Potential outcomes of gene duplication

Gene duplication can lead to gene redundancy or novel functions.

reason gene duplication is important

Gene duplication allows new functions to evolve.

the relationship at the molecular level between mutant alleles and phenotype

A mutant allele can have different effects depending on the gene product's function. The wild-type allele is always dominant.

connection point between sister chromatids

Centromere

consequences of nondisjunction

Nondisjunction can lead to aneuploidy, which is an abnormal number of chromosomes in a cell.

genetic variation during meiosis

Crossing over

Has occurred at the end of meiosis I

Homologous chromosome pairs are separated into separate daughter cells

Gregor Mendel's experiments established

key laws of inheritance based on his experiments: The law of segregation and independent assortment.

essential gene

A gene that encodes a gene product required for life, which cannot be compensated for.

essential genes and nonessential genes

Essential genes are required for survival, while nonessential genes may provide beneficial traits but are not critical for survival.

nondisjunction

The process where homologous chromosomes or sister chromatids fail to separate properly during cell division.

trisomic gamete fertilizes a normal gamete

The zygote would have an extra chromosome, resulting in a trisomy.

significance of the G0 phase

The G0 phase is significant as it represents a state where cells are not actively preparing to divide, allowing for differentiation or a temporary halt in the cell cycle.

incomplete dominance

In incomplete dominance, the phenotype of the heterozygote is an intermediate blend of the two homozygous phenotypes, while in complete dominance, the phenotype of the heterozygote is identical to that of one of the homozygotes.

chromosome to remain constant

To ensure that each daughter cell receives the same number of chromosomes as the parent cell.

The process by which meiotic cell division contributes to genetic diversity

Independent assortment and Crossing over

genotype that is homozygous

two alleles that are the same

statements about independent assortment

correct: the homologous pairs line up at the metaphase plate at random, independently of the others.

G2 phase activity

Preparation for division

silenced located gene

The expression of that gene would likely decrease or be silenced.

Spindle fibers contribute

Spindle fibers ensure that chromosomes are evenly distributed to daughter cells by attaching to centromeres and pulling them apart.

plant species exhibits incomplete dominance

The expected phenotypic ratio would be 1 red: 2 pink: 1 white.

epistasis

A gene interaction in which the effects of an allele of one gene mask the effects of the alleles of a second gene

stage of meiosis does diakinesis

Prophase I

wildtype and mutant allele regarding the anti-thrombin gene?

Wildtype allele is a functional allele whereas a mutant allele is nonfunctional.

haploid

Cells with half the number of chromosomes

metaphase

Ensuring proper separation of chromosomes during anaphase

gene

unit of heredity; a sequence of DNA that affects one or more traits in an organism, usually through an encoded protein produced based on the sequence of nucleotides.

allele

An allele is a variant form of a gene.

fails to form a metaphase plate

Improper separation of chromosomes

event that occurs during the diplotene stage of meiosis?

The synaptonemal complex starts to dissociate.

role of spindle fibers during cell division?

To help separate chromosomes by attaching to the centromeres.

responsible for genetic variation in meiosis

Crossing over and Independent assortment

Diplotene

is the stage of meiosis I where the synaptonemal complex starts to dissolve and chiasmata are visible

phenotypic expression

Epistasis influence phenotypic expression by masking the effects of other genes, leading to variations in traits that are not solely determined by individual genes.

position effect

Changes in gene expression due to gene relocation on a chromosome.

paracentric inversion

It does not include the centromere.

Eukaryotic chromosomes

Eukaryotic chromosomes are organized into chromatin, which can be euchromatin or heterochromatin.

chromosome abnormality that causes Down syndrome

A nondisjunction results in a person with an extra copy of chromosome 21.

Chromosome condensation

Chromosome condensation is crucial for ensuring that DNA is properly segregated during cell division.

Haploid

After cell division, the cell has half the number of chromosomes as the original mother cell

gene expression

the transcription and subsequent translation of a protein coding gene.