Bio Exam 3 all vocab

Alternation of generations

when there is both a diploid and haploid multicellular stage

Asexual reproduction

when a single individual passes along all of its genes to its offspring without the fusion of gametes

Autosomes

non sex chromosomes

Chiasmata

the X shape in crossing over

Clone

when progeny is genetically identical to it's parents

Crossing over

occurs during prophase 1 when parts of chromosomes from 1 parent transfer to the second chromosome (homolog)

Diploid cell

2 sets of chromosomes

Fertilization

union of gametes

Genes

units of heredity made up of DNA

Genetics

the study of heredity and inherited variation

Haploid cell

1 set of chromosomes

Heredity

transmission of traits from one generation to another

Homologous chromosomes (homologs)

the two chromosomes in each pair from a different parent (different from sister chromatids)

Karyotype

ordered display of the pairs of chromosomes from a cell

Life-cycle

generation to generation sequence of stages in the reproductive history of an organism

Locus

the specific position of a gene along a chromosome

Meiosis

production of gametes

Meiosis I

the first stage of meiosis

Meiosis II

the second stage of meiosis

Recombinant chromosomes

combined DNA inherited from both parents on the same chromosome

Sex chromosomes

x and y

Sexual reproduction

two parents have gametes fuse giving rise to offspring with unique combinations of genes

Synapsis

when DNA breaks are repaired and the one nonsister chromatid is joined

Synaptonemal complex

a zipper like structure that holds the homologs together

Variation

the differences between progeny and parental generation

Zygote

fertilized egg with 1 set of chromosomes from each parent

Character

heritable feature

Trait

variation on a character

True breeding

completely known genealogy

Hybridization

mixing true-bred organisms

F1

first filial generation

F2

Second filial generation

Dominant allele

determines the organisms appearance

Recessive allele

no noticeable effect on appearance

Law of segregation

two alleles for each heritable character separate during gamete formation

Punnett Square

method used to determine likely outcomes in breeding

Homozygote (homozygous)

two identical alleles for a gene

Heterozygote (heterozygous)

two different alleles for a gene

Phenotype

physical appearance (or metabolic activity)

Genotype

the genetic makeup

Testcross

breeding an unknown with a known

Monohybrid

one trait studied

Dihybrid

two traits studied

Law of independent assortment

each pair of alleles segregates independently

Multiplication and Addition rule

learn by practicing!

Complete dominance

Occurs when phenotypes of the heterozygote and dominant homozygote are identical.

Incomplete dominance

The phenotype of F1 hybrids is somewhere between the phenotypes of the two parental varieties.

Codominance

Two dominant alleles affect the phenotype in separate, distinguishable ways.

Pleiotropy

One gene multiple affects.

Epistasis

Expression of a gene at one locus alters the phenotypic expression of a gene at a second locus.

Quantitative characters

Those that vary in the population along a continuum.

Polygenic inheritance

An additive effect of two or more genes on a single phenotype.

Multifactorial

When expression is influenced by the environment.

Pedigree

A family tree that describes inheritance of a trait across generations.

Carriers

Heterozygous for a recessive allele.

Amniocentesis

The liquid that bathes the fetus is removed and tested for certain genetic disorders.

Chorionic villus sampling (CVS)

A sample of the placenta is removed and tested.

Aneuploidy

Abnormal number of a particular chromosomes.

Barr body

The inactivated x chromosome.

Chromosome theory of inheritance

Chromosomes exist and are passed on from parent to child, containing the DNA.

Deletion

Removes a chromosomal fragment.

Duplication

Repeats a segment.

Genetic maps

An ordered list of the genetic loci along a particular chromosome.

Genetic recombination

The production of offspring with combinations of traits differing from either parent.

Inversion

Reverses orientation of a segment within a chromosome.

Linkage map

Genetic map of a chromosome based on recombination frequencies.

Linked genes

Genes on the same X chromosome.

Map units

1% recombination frequency.

Monosomic

Zygote has only one copy of a particular chromosome.

Nondisjunction

Pairs of homologous chromosomes do not separate normally during meiosis.

Parental types

Offspring with a phenotype like the parent.

Polyploidy

A condition in which an organism has more than two complete sets of chromosomes.

Recombinant types (recombinants)

Offspring with non parental types.

Sex-linked

When a trait is on either sex chromosome.

Translocation

Moves a segment from one chromosome to another.

Trisomic

Zygote has three copies of a particular chromosome.

Wild type

Normal phenotypes.

X-linked

Genes on the X chromosome.

Antiparallel

Their subunits run in opposite directions.

Bacteriophages (phages)

Viruses that infect bacteria.

Chromatin

DNA with proteins.

DNA ligase

Puts together the Okazaki fragments.

DNA polymerase I

Fixes DNA.

DNA Polymerase III

Catalyzes the synthesis of new DNA at a replication fork.

DNA replication

The copying of DNA.

Double helix

The pattern of DNA.

Euchromatin

loosely packed chromatin

Helicases

enzymes that untwist the double helix at the replication forks

Heterochromatin

densely packed DNA (centromeres and telomeres)

Histones

proteins that are responsible for the main level of DNA packing in interphase chromatin

Lagging Strand

the second strand of DNA replicated 5'-3' but in fragments

Leading strand

the DNA strand that is made continuously

Mismatch repair

when DNA bases don't match, repair enzymes replace the incorrectly paired nucleotides

Nucleosome

compound of DNA wound twice around a core of eight histones, two each of the four main histone types

Nucleotide excision repair

a nuclease cuts out and replaces damaged stretches of DNA

Okazaki fragments

segments made on the lagging strand

Origins of replication

where replication starts

Primase

synthesizes the RNA primer

Primer

the piece of RNA that makes the initial nucleotide chain

Replication fork

y shaped region where parental DNA strands are being unwound