Flashcards EBIO 2070 EXAM 1 (CU Boulder)

transmission genetics

classical genetics; heredity and how traits are passed between generations; chromosomes; gene mapping

molecular genetics

chemical nature of genes; replication, transcription, translation, gene regulation; structure, organization, function of genes

population genetics

genetic composition of groups of individuals of same species, how composition changes geographically and chronologically; study of evolution/genetic change

model genetic organism

organisms that have a great deal of their genetic information known and that have characteristics that make them particularly useful for genetic analysis; Drosophila, E. coli, C. elegans (nematode worm), A. thaliana (thale-cress plant), M. muculus (house mouse), S. cerevisiae (baker's yeast), A. mexicanus (blind cave fish)

prokaryote

no nuclear membrane, no membrane-bound organelles

eukaryote

nucleus, membrane-bound organelles such as chloroplasts, mitochondria

histone

proteins that DNA wraps around to be more dense in chromatin

Angiotensin Converting Enzyme (ACE)

Controls circulatory function tissue growth and can be encoded to improve human physical performance

prokaryote

Unicellular organism with a relatively simple cell structure

Eukaryote

A compartmentalized cell structure with components bounded by intracellular membranes; either unicellular or multicellular

haploid

Possessing one set of chromosomes (one genome)

diploid

Possessing two sets of chromosomes (two genomes)

eubacteria

One of the three primary divisions of life. Consists of unicellular organisms with prokaryotic cells and include most of the common bacteria

archaebacteria

One of three primary divisions of life. Archaea consist of unicellular organisms with prokaryotic cells

prophase

Stage of mitosis. the chromosomes contract and become visible, the cytoskeleton breaks down, and the mitotic spindle begins to form.

metaphase

Stage of mitosis. Chromosomes align in the center of the cell.

anaphase

Stage of mitosis in which chromatids separate and move toward the spindle poles.

telophase

Stage of mitosis. The chromosomes arrive at the spindle poles, the nuclear membrane re-forms, and the chromosomes relax and lengthen.

histone

Low-moluecular-weight protein found in eukaryotes that complexes with DNA to form chromosomes

chromatin

Material found in the eukaryotic nucleus; consists of DNA and proteins

homologous chromosomes

Two chromosomes that are alike in structure and size and that carry genetic information for the same set of hereditary characteristics. One chromosome of a homologous pair is inherited from the male parent and the other is from the female parent.

synapsis

Close paring of homologous chromosomes

chiasma

Point of attachment between homologous chromosomes at which crossing over took place.

tetrad

The four products of meiosis; all four chromatids of a homologous pair of chromosomes.

mitosis

Process by which the nucleus of a eukaryotic cell divides.

meiosis

Process in which chromosomes of a eukaryotic cell divide to give rise to haploid reproductive cells.

reduction division

(genetics) cell division that produces reproductive cells in sexually reproducing organisms; the nucleus divides into four nuclei each containing half the chromosome number (leading to gametes in animals and spores in plants).

equational division

The second meiotic division is an _______ ________ because it does not reduce chromosome numbers. A nuclear division that maintains the same ploidy level of the cell.

centromere

Constricted region on a chromosome that stains less strongly than the rest of the chromosome; region where spindle microtubules attach to a chromosome

origin of replication

Sequence of nucleotides where replication is initiated.

telomere

Stable end of a chromosome.

primary spermatocytes

Spermatogonium that has entered prophase I.

secondary spermatocytes

Product of meiosis I in male animals.

spermatids

Immediate product of meiosis II in spermatogenesis

oogonium

Diploid cell in the ovary; capable of undergoing meiosis to produce an egg cell.

primary oocytes

Oogonium that has entered prophase I.

secondary oocytes

One of the products of meiosis I in female animals; receives most of the cytoplasm

polar body

ovum

Final product of oogenesis

fertilization

Fusion of gametes (sex cells) to form a zygote

crossing over

Exchange of genetic material between homologous but non sister chromatids

recombination

Process that produces new combinations of alleles.

(Gregor) Mendel

Augustinian monk and botanist whose experiments in breeding garden peas led to his eventual recognition as founder of the science of genetics (1822-1884)

(Reginald) Punnett (1917)

Coined the term "punnet square"

Gene

Genetic factor that helps determine a trait; often defined at the molecular level as a DNA sequence that is transcribed into an RNA molecule.

Allele

One or two or more alternate forms of a gene

locus

Position on a chromosome where a specific gene is located.

genotype

The set of genes possessed by an individual organism

phenotype

Appearance or manifestation of a characteristic

homozygous

Refers to a individual organism that possesses two identical alleles at a locus

heterozygous

Refers to an individual organism hat possesses two different alleles at a locus

dominant

Refers to an allele or a phenotype that is expressed in homozygotes (AA) and in heterozygous (Aa); only the _____ allele is expressed in a heterozygote phenotype.

recessive

Refers to an allele or phenotype that is expressed only when the recessive allele is present in two copies (homozygous). This allele is not expressed in the heterozygous phenotype.

segregation

the principle, originated by Gregor Mendel, stating that during the production of gametes the two copies of each hereditary factor_______________ so that offspring acquire one factor from each parent.

independent assortment

Independent separation of chromosome pairs in anaphase I of meiosis; contributes to genetic variation.

Punnett Square

Shorthand method of determining the outcome of a genetic cross. On a grid, the gametes of one parent are written along the upper edge and the gametes of the parent are written along the left-hand edge.

addition rule

States that the probability of any f two or more mutually exclusive events occurring is calculated by adding the probabilities of the individual events

multiplication rule

States that the probability of two or more independent events occurring together is calculated by multiplying the probabilities of each of the individual events.

testcross

A cross between an individual with an unknown genotype and an individual with the homozygous recessive genotype.

albinism

A hereditary, congenital disorder characterized by the complete or partial lack of pigmentation production in plants, animals, or humans

Chi-square goodness of fit test

statistical test used to evaluate how well a set of observed values fit the expected values. The probability associated with a calculated chi-square value is the probability that the difference between the observed and the expected values may be due to chance.

Sex determination

Specification of sex (male or female). Sex determining mechanisms include chromosomal, genic, and environmental __________ systems.

hermaphroditism

Condition in which an individual organism posses both male and female reproductive structures. True ______ produce both male and female gametes.

monoecious organism

Individual organism that has both male and female reproductive structures.

dioecious organism

belongs to a species whose members have either male or female reproductive structures.

autosomes

Chromosome that is the same in males and females; nonsex chromosome

heterogametic

The sex (male or female) that produces two types of gametes with respect to sex chromosomes. (Ex. in the XX-XX sex-determining system, the male produces both X-bearing and Y-bearing gametes.)

homogametic

The sex (male or female) that produces gametes that are all alike with regard to sex chromosomes. (ex. in the XX-XY sex-determining system, the female produces only the X-bearing gametes. s

genic sex determination

Sex determination in which the sexual phenotype is specified by genes at one or more loci, but there are no obvious differences in the chromosomes of males and females.

sequential hermaphroditism

Phenomenon in which the sex of an individual organism changes in the course of its lifetime; the organism is male at one age or developmental stage and female at a different age or stage.

genic balance sex determination

instead of XY chromosomes, sex is determined by the genic balance or ratio between X-chromosomes and autosome genomes.

Turner syndrome

Human condition in which cells contain a single X chromosome and no Y chromosome (XO). Persons with ________ __________ are female in appearance but do not undergo puberty and have poorly developed female secondary sex characteristics; most are sterile but have normal intelligence.

Klinefelter syndrome

Human condition in which cells contain one or more Y chromosomes along with multiple X chromosomes (most commonly XXY but may also be XXXY, XXXXXY, or XXYY). Persons with ______ ________ are male in appearance but frequently possess small testes, some breast enlargement, and reduced facial and pubic hair; often taller than normal and sterile, most have normal intelligence.

SRY gene

On the Y chromosome, a gene that triggers male development.

hemizygous

Possession of a single allele at a locus. Males of organisms with XX-XY sex determination are homozygous for X-linked loci because their cells possess a single X chromosome.

non-disjunction

Failure of homologous chromosomes or sister chromatids to separate in meiosis or mitosis.

human color blindness

the inability to clearly distinguish different colors of the spectrum. People tend to see colors in a limited range of hues; a rare few may not see colors at all.

dosage compensation

Equalization in males and females of the amount of protein produced by X-linked genes. In placental mammals, ________ ________ is accomplished by the random inactivation of one X chromosome in the cells of females.

Barr body

Condensed, darkly staining structure that is found in most cells of female placental mammals and is an inactivated X chromosome

Lyon hypothesis

Proposes that one X chromosome in each female cell becomes inactivated (a Barr body) and suggests that which of the X chromosomes becomes inactivated is random and varies from cell to cell.

complete dominance

Refers to an allele or a phenotype that is expressed in homozygotes (AA) and in heterozygotes (Aa); only the dominant allele is expressed in a heterozygote phenotype.

incomplete dominance

Refers to the phenotype of a heterozygote that is intermediate between the phenotypes of the two homozygotes.

codominance

Type of allelic interaction in which the heterozygote simultaneously expresses traits of both homozygotes

penetrance

Percentage of individuals with a particular genotype that express the phenotype expected of that genotype.

expressivity

Degree to which a trait is expressed

multiple alleles

Presence in a group of individuals of more than two alleles at a locus. However, each member of the group has only two of the possible alleles.

ABO locus

determines the ABO blood group of an individual by modifying the oligosaccharides on cell surface glycoproteins. Variations in the sequence of the protein between individuals determine the type of modification and the blood group

H locus

The ___ _______ is not the same gene as the ABO locus, but it is epistatic to the ABO locus, providing the substrate for the A and B alleles to modify. The ___ ____ encodes the fucosyltransferase that produces the H antigen on red blood cells.

epistasis

Type of gene interaction in which a gene at one locus masks or suppresses the effects of a gene at a different locus.

Labrador Retriever coat color

9 different genotypes that can result in labrador genetics. 3 possible phenotypes (black, brown, yellow).

cytoplasmic inheritance

Inheritance of characters encoded by genes located in the cytoplasm. Because the cytoplasm is usually contributed entirely by only one parent, most _______ _______ characteristics are inherited from a single parent.

genetic maternal effect

Determines the phenotype of a an offspring. With _______ ________ ________, an offspring inherits genes for the characteristics from both parents, but the offspring's phenotype is determined not by its own genotype but by the nuclear genotype of its mother.

sinistral

of, relating to, or inclined to the left

dextral

Of, relating to, or located on the right side

proband

A person serving as the starting point for the genetic study of a family

consanguinity

Relationship by descent from a common ancestor

dizygotic twins

"fraternal"; twins develop from two different eggs; each are fertilized by separate sperm cells

monozygotic twins

"identical"; twins develop from just one zygote that will then split and form two embryos

concordance in twins

The presence of the same trait in both members of a pair of twins

amniocentisis

The sampling of amniotic fluid using a hollow needle inserted into the uterus, to screen for developmental abnormalities in a fetus