Genetics Important Terms

genetics

study of heredity

genome

The complete set of genetic instructions for any organism

transmission genetics

Basic principles of heredity - how traits are passed from one generation to the next; Mendelian genetics

molecular genetics

How genetic information is encoded, replicated, and translation

population genetics

The genetic composition of populations and the changes geographically and over time

model genetic organism

Widely used in gene research to serve as models for the genetic systems of other organisms

pangenesis

Each part of the body contains genetic information for that particular part

inheritance of acquired characteristics

Which traits acquired in a person’s lifetime become incorporated into that person’s hereditary information and are passed on to offspring; tanning bed = kids will be tan

performationism

Inside the egg or sperm there exists a fully formed miniature adult which simply enlarges in the course of development

blending inheritance

The traits of offspring are a blend, or mixture, of parental traits; blue + yellow = green

cell theory

All life is composed of cells, cells arise only from preexisting cells, and the cell is the fundamental unit of structure and function in living organisms.

germ-plasm theory

The cells in the reproductive organs carry a complete set of genetic information that is passed to the egg and sperm

prokaryote

Unicellular organism with a relatively simple cell structure

eukaryote

Compartmentalized cell structure bounded by intracellular membranes; unicellular or multicellular

bacteria

Prokaryote; both good and bad kinds

archaea

Prokaryote; can survive in harsh conditions

nucleus

Separates the DNA from other cell components with a nuclear membrane

histones

Proteins that help tightly pack chromosomes, regulate accessibility of DNA to enzymes/other proteins to copy and read

chromatin

DNA + histones =

virus

Simple structures composed of an outer protein coat surrounding either DNA or RNA

bacteriophages

Viruses that infect bacteria

homologous pair

One chromosome has a corresponding chromosome in the other set (2)

diploid

Cells that carry two sets of genetic information

haploid

Cells that contain one set of genetic information

polyploid

Cells that contain more than two sets of genetic information

centromere

A constricted region on the chromosome and the attachment point for spindle microtubules

microtubules

The filaments responsible for moving chromosomes in cell division

telomeres

Specific DNA sequences and associated proteins located at the tips of the whole linear chromosomes; stability

origin of replication

site for DNA synthesis beginning

sister chromatids

Two identical copies of a chromosome connected by centromere; each have one molecule of DNA

cell cycle

Series of stages through which a cell passes from one division to the next

checkpoints

Allow or prohibit the cell’s progression to the next stage

interphase

Cell grows, develops, and functions

prophase

Stage 1 of M

prometaphase

Stage 2 of M

metaphase

Stage 3 of M

anaphase

Stage 4 of M

telophase

Stage 5 of M

cytokinesis

Stage 6 of M

G1

Cell grows and proteins necessary for cell division are synthesizes

G1/S

Cell makes sure all enzymes and proteins necessary for replication are made

G0

Cell arrests

S phase

Cell synthesizes DNA = sister chromatids

G2

Cell has biochemical events for cell division to take place

G2/M

Cell must be completely replicated and undamaged

meiosis

Creates gametes with half the number of chromosomes

fertilization

Two haploid gametes fuse and restore number of chromosomes to diploid

crossing over

Homologous chromosomes exchange genetic information

chiasma

Cells cross here

interkinesis

Nuclear membrane reforms around the chromosomes clustered at each pole, spindle breaks down, chromosomes relax

synaptonemal complex

A protein structure forms between the paired homologous chromosomes to hold them tightly together

recombination

The creation of new combinations of alleles on a chromatid

cohesin

A protein that holds chromatids together

spermatogenesis

Production of male gametes

primary gamete

Gamete is diploid

secondary gamete

Gamete is haploid

spermatids

The resulting two haploid gametes

oogenesis

Production of female gametes

spermatocyte

Male gamete cell

oocyte

Female gamete cell

ovum

Mature female gamete cell

microsporocytes

Male diploid reproductive cells in stamen

microspores

Male haploid reproductive cells in stamen

megasporocytes

Female diploid reproductive cells in ovary

megaspores

Female haploid reproductive cells in ovary

gene

Inherited factor that determines characteristic

allele

Alternative forms of a gene

locus

Specific place on a chromosome occupied by an allele

genotype

Set of alleles possessed by an individual organism

homozygote

Two same alleles

heterozygous

Two different alleles

phenotype

appearance of a characteristic

characteristic

a general feature

trait

manifestation of a feature

monohybrid crosses

cross between parents differing in a single characteristic

P generation

First generation of cross

F1 generation

First offspring generation of cross

reciprocal crosses

cross where the gender or phenotype of parents are reversed

F2 generation

Second offspring generation of cross

principle of segregation

Individual organism possesses two alleles for any characteristic; one from mom, one from dad

backcross

Cross between P and F1

multiplication rule

Two or more independent events occurring together

addition rule

Two or more exclusive events occurring

conditional probability

One event occurring after the other

testcross

One unknown genotype is crossed with a homozygous recessive genotype

dihybrid crosses

cross between parents differing in two characteristics

principle of independent assortment

Alleles at different loci separate independently of one another

chi-square goodness-of-fit test

How well observed values fit expected values