Genetics Exam 2

Mitosis produces how many daughter cells?

2 genetically identical

Definition of Reciprocal Translocation

2 non-homologous chromosomes exchange genetic material

Radial Loop Domains are what level of compaction?

3rd

Meiosis produces how many daughter cells?

4 non-genetically identical

How many Barr bodies would an individual with a X0 genotype possess? A. 0 B. 1 C. 2 D. 3

A. 0

The Lyon hypothesis attempts to explain the molecular mechanism of _____. A. X-inactivation B. genomic imprinting C. maternal inheritance D. extra nuclear inheritance

A. X-inactivation

In a Z-W system, which is considered to be the homogametic sex? A. males B. females C. Hermaphrodite D. None of the above

A. males

Definition of Genome

All the genetic information in an organism

What are the 3 Types of Microtubules?

Aster, Polar, and Kinetochore Microtubules

What gene is encoded in the Xic? A. Xce B. Xist C. TsiX D. TsiY

B. Xist

Z-Y System Males/Females

(birds and some fish) Male: Z-Z Female: Z-W

How Can a Mutant Allele be Dominant?

- gain of function (hypermorph) - dominant-negative (antimorph) - haploinsufficiency (neomorph)

Definition of Chromatin

DNA protein complex formed during compaction of linear DNA

What is Homologous Recombination?

DNA strand is damaged and uses other DNA strand to repair itself

Primary Ways Chromosome Structure can be altered by mutations

Deletion Duplication Inversion Translocation

Haploid Plant is a _____

Gametophyte

Definition of Genetic Polymorphism

In large populations, there may be more than one common allele (wild type)

Eukaryotic Cell Cycle

Interphase (g1, s phase, g2 phase) and then Mitotic phase (mitosis, cytokinesis)

Meiosis: Steps of Prophase I

Lebtotene Zygotene Pachytene Diplotene Diakinesis

X-O System Males/Females

Male: X-Y, X-O, Female: X-X

X-Y System Males/Females

Males: X-Y, X-X-Y - heterogametic Females: X-X, X-O - homogametic

Definition of Sex Determination

Mechanism where an individual develops into male or female

Definition of Arocentric

More off center centromere

Definition of Gene Interaction

Occur when 2 or more different genes influence the outcome of a single threat

Definition of Cell Division

Process by which a cell divides into two new daughter cells

Steps of Meiosis I

Prophase I, Metaphase I, Anaphase I, Telophase I

Definition of Euploidy

Variation in number of complete sets of chromosomes

3 Different Sex Chromosome Systems

X-Y, X-O, Z-W

Definition of Recessive Mutant Alleles

allele that has been altered by mutation, rare, allele is defective

Definition of Lethal Alleles

alleles that have the most detrimental effect on phenotype --> death, result of mutation in essential gene

Definition of Sex Influenced Trait

an allele is dominant in one sex but recessive in the opposite sex, autosomal

Definition Robertsonian Translocation

an entire chromosome attached to another

Where are Kinetochore Microtubules Located?

attach to kinetochore on the centromere of the chromosomes

Definition of Behavioral Sex Determination

behavioral interactions can determine sex

Definition of Somatic Cells

body cells other than gametes

Definition of Paracentric Inverstion

centromere lies outside inverted region

Definition of Pericentric Inversion

centromere lies within inverted region

Definition of Metacentric

centromere near middle

Definition of Polymorphism

change in gene (less rare than mutations)

Definition of Internal Nuclear Matrix

connects to lamina, fills nucleus interior

Definition of Gene Duplication

creates similar genes (sparalogs) (humans have ~2-3 copies of similar genes)

Chromosome Classification: Banding Pattern

dark bands= tightly compacted regions light bands= loose compacted regions

Definition of Nuclear Lamina

fibers lining inner membrane

Where are Aster Microtubules Located?

from the centrosome to the plasma membrane

Definition of Dominant Mutant Alleles

gain of function, less common than recessive alleles.

Definition of Isogamous

gametes are morphologically similar ex: many species of fungi and algae

Definition of Heterogamous

gametes that are morphologically different (sperm and egg)

What are functional sites along bacterial chromosomes?

genes intergenetic regions origin of replication repetitive sequences

What are functional sites along eukaryotic chromosomes?

genes origin of replication centromeres telomeres repetitive sequences

Definition of Non-Essential Gene

genes that are not absolutely necessary for survival, but beneficial

Definition of Essential Gene

genes that are required for survival (only 1/3)

Definition of Polyploids

have an odd number of chromosome sets, usually sterile

Definition of Incomplete dominance

heterozygote exhibits a phenotype that is intermediate between phenotypes of 2 zygotes

Overdominance (Heterozygote Advantage)

heterozygote has a greater reproductive success compared to either homozygotes

Definition of Linker Histone Protein

histone that binds DNA in linker region between nucleosomes and help to compact

Definition of Ortholog

homologs within a different species

Definition of Paralog

homologs within a single species

Steps of Mitosis

interphase, prophase, metaphase, anaphase, telophase, cytokinesis

Egg/Ovum Cell Characteristics

large and immobile

Chromosome Classification: Size

largest to smallest

Definition of Mutant Alleles

less common version of gene, often defective

Definition of Euchromatin

less condensed regions of chromosomes, active, radial loops

Chromosome Classification: Position of Centromere

metacentric submetacentric arocentric telocentric

Definition of Pleiotropic Effects

multiple effects of a single gene on the phenotype of an organism

Definition of Gene Redundancy

one gene can compensate for loss-of-function of other gene, no effect on phenotype

What is Oogenesis?

production of egg cells (in ovaries)

What is Spermatogenesis?

production of sperm (in testes)

Definition of Complementation

products of offspring with a wild-type phenotype from parents that both display the same/similar recessive phenotype

Where are Polar Microtubules Located?

project from the centrosomes to the middle,

What is a Cytogeneticist?

scientist who studies chromosomes under microscope

Definition of Chromosomal Translocation

segment of one chromosome becomes attached to another

What is the SRY Gene?

sex determining region of the Y chromosome

Definition of Haploid Sex Determination

sex is determined by number of sets of chromosomes

Definition of Terminal Deletion

single break

Chromosome Classification

size position of centromere banding pattern

Definition of Submetacentric

slightly off center centromere

Definition of Bacterial Plasmids

small DNA molecule within a cell that is physically separated from chromosomal DNA & can replace it

Sperm Cell Characteristics

small and mobile

What species have Temperature-Dependent Sex Determination?

some reptiles and fish

Definition of Telomere

specialized sequences located at both ends of the linear chromosome

Definition of Gametes

sperm and egg cells

Meiosis produces haploid cells called _______

spores

Definition of Chromosomes

structure within living cells that contains genetic material

Definition of Protandrous Hermaphrodite

switch from male to female

Definition of Wild Type Alleles (WT)

the most prevalent version of a gene in wild population

Definition of Centromere

the region of the chromosome that holds the two sister chromatids together during mitosis

Definition of Heterochromatin

tightly compacted regions of chromosomes, inactive, compacted radial loops

Definition of Sex Linked Traits

traits that occur only in 1 of 2 sexes, can be autosomal or sex linked

Definition of Genetic Linkage

transmission of genes located close to each other on the same chromosome violates law of independent assortment

Definition of Codominance

two alleles of the same gene are present (heterozygous) and both are expressed

Definition of Interstitial Deletion

two breaks and reattachment of outer pieces

Definition of Homolog

two or more genes derived from a common ancestor

Definition of Aneuploidy

variation in number of particular chromosomes within a set

Definition of Epistasis

when a gene can mask the phenotypic effects of another gene

Definition of Mutation

a change in DNA sequence, rare, affecting phenotype

The genetic control of X-inactivation is governed by a short region on the X chromosome called the _______. A. Y-inactivation center (Yic) B. condensation center C. X-inactivation center (Xic) D. X-initiation center

C. X-inactivation center (Xic)

Definition of Telocentric

Centromere at the end

Steps of Meiosis II

Prophase II, Metaphase II, Anaphase II, Telophase II

What are the 2 Different Types of Homologous Recombination?

Sister Chromatid Exchange Between Homologous Chromosomes

Diploid plant is a _____

Sporophyte