Genetic Vocab Terms

Law of Dominance

one member of a gene pair may mask or prevent expression of the other

law of segregation

only one member of a gene pair can be in the gamete

law of independent assortment

does not matter if a gene is dominant or recessive, it has an equal chance of being put in a gamete

punnett square

shows probability of specific characteristics passed down from parents

gregor mendel

austrian monk, father of genetics

recessive

when not masked by a dominant characteristic inherited from one parent

mutation

a variant form of the structure of a gene that may be transmitted to subsequent generations

self- pollination

the pollination of a flower by pollen from the same flower or from another flower on the same plant

anther

the part of a stamen that contains the pollen

down syndrome

a condition in which a person has an extra chromosome

gamete

a mature haploid male or female germ cell which is able to unite with another of the opposite sex in sexual reproduction to form a zygote

phenotype

the set of observable characteristics of an individual resulting from the interaction of its genotype with the environment

mitosis

a type of cell division that results in two daughter cells each having the same number and kind of chromosomes as the parent nucleus

multiple alleles

the alternative forms of the same gene so they influence the same trait

diploid

containing two complete sets of chromosomes, one from each parent

dominant

most important, powerful, or influential gene

R.C. Punnett

british geneticist that created the punnett square

germ

a microorganism that typically causes disease

hybrid

the offspring of two plants or animals of different species or varieties

cross- pollination

the process of applying pollen from one flower to the pistils of another flower

stamen

the male fertilizing organ of a flower

monohybrid

a hybrid that is heterozygous with respect to a specified gene

zygote

a diploid cell resulting from the fusion of two haploid gametes; a fertilized ovum

nondisjunction

the failure of one or more pairs of homologous chromosomes or sister chromatids to separate normally during nuclear division

homozygous

having two identical alleles of a particular gene or genes

karyotype

an individual's complete set of chromosomes

haploid

having a single set of unpaired chromosomes

polyploid

containing more than two homologous sets of chromosomes

genetics

the study of genes

heredity

the passing on of physical or mental characteristics genetically from one generation to another

somatic

relating to the body, especially as distinct from the mind

drosophila

genus of flies whos genes can easily be mapped to investigate genetic transmission

pistil

the female organs of a flower, comprising the stigma, style, and ovary

stigma

the part of the pistil where pollen germinates

dihybrid

a hybrid that is heterozygous for alleles of two different genes

genotype

the genetic constitution of an individual organism

meiosis

a type of cell division in sexually reproducing organisms that reduces the number of chromosomes in gametes

heterozygous

having two different alleles of a particular gene or genes

fraternal twins

result from the fertilization of two separate eggs with two different sperm during the same pregnancy

identical twins

result of the fertilization of one egg by one sperm that divides before it implants

gestation period

the time between conception and birth

aminocentesis

the sampling of amniotic fluid using a hollow needle inserted into the uterus, to screen for developmental abnormalities in a fetus. this is very awful. 0/10,

autosomes

any chromosome that is not a sex chromosome

calyx

the sepals of a flower, typically forming a whorl that encloses the petals and forms a protective layer around a flower in bud.

cancer

a disease caused by an uncontrolled division of abnormal cells in a part of the body

corolla

a collection of petals that strongly displays colour and encircles the stamen and carpel, the reproductive organs of a flower

homologous

having the same relation, relative position, or structure

ovary

female reproductive organ in which ova or eggs are produced, present in humans and other vertebrates as a pair

petals

one of the modified often brightly colored leaves of the corolla of a flower

klinefelters syndrome

where boys are born with an extra X chromosome, resulting in them having effeminate characteristics

chromatin

the material of which the chromosomes of organisms other than bacteria are composed

placenta previa

when the placenta attaches low in the uterus

ectopic pregnancy

when the zygote implants in the fallopian tube

trisomy

the affected person has three copies of one of the chromosomes instead of two

sex chromosomes

chromosome involved in sex determination- x and y

puberty

the period during which adolescents reach sexual maturity and become capable of reproduction

turners syndrome

results when one of the X chromosomes (sex chromosomes) is missing or partially missing

crossing over

a cellular process that happens during meiosis when chromosomes of the same type are lined up

chiasmata

specialized chromatin structures that link homologous chromosomes together until anaphase I. also the sight of crossing-over

freemartin calf

a hermaphrodite or imperfect sterile female calf which is the twin of a male calf whose hormones affected its development

pollen

fine powdery substance, typically yellow, consisting of microscopic grains discharged from the male part of a flower or from a male cone. Each grain contains a male gamete that can fertilize the female ovule, to which pollen is transported by the wind, insects, or other animals.

polar body

the byproduct of an oocyte meiotic division. It is the small cell that normally apoptoses, and in textbook figures, it usually just disappears

placenta

an organ that develops in the uterus during pregnancy