AP Bio Unit 5 Vocabulary

Gene

Section of DNA that codes for characteristics of alleles; can be transferred from one generation to the next.

Allele

Alternate forms of genes that organisms inherit from both parents; includes dominant and recessive alleles

Trait

A genetically determined characteristic of an organism

Genotype

Refers to the alleles and individual receives at fertilization

Nucleic acids

Carriers of genetic information

Ribosomes

Synthesize proteins based on nucleic acid sequences

Phenotype

Physical appearance based on genotype; protein produced from alleles

Homozygous

Genotype with the same alleles

Heterozygous

Genotype with different alleles

Dominant allele

DNA that produces fully functioning protein; capital letter

Recessive allele

DNA that produces a protein with little or no function; lowercase letter

Law of dominance

States that only one form of the trade will appear in the next generation

Non-nuclear

Free, floating DNA that is not in the nucleus

Gregor Mendel

The father of genetics

P generation

The parent generation

F1 generation

The offspring of P generation

F2 Generation

Offspring of the F1 generation

Particular theory

Describes particles (genes) being individually responsible for a person’s traits

Punnet Square

Illustrates the possible outcomes of the traits of an offspring

Monohybrid cross

Examines how one trait is inherited; the cross of a single trait

Purebed

Homozygous

Hybrids

Heterozygous

Law of segregation

States that each organism has two factors for each trait that separate during gamete formation (meiosis, metaphase II)

Dihybrid cross

Examines how two traits are inherited

Locus

Location of a gene on homologous chromosomes

Law of independent assortment

States that two or more genes segregate independently of each other

Random fertilization

The concept that any of the genetically unique sperm created by a male can join with any of the genetically unique eggs created by a female

Law of probability

The mathematical measure of the likelihood of genetics; multiply – and; add – or

Autosomal disorder

Genes found on chromosomes 1-22

Nondisjunction

The failure of chromosomes to fully separate during the formation of gametes; results in too many or two few chromosomes

Autosomal recessive disorder

When the individual needs both recessive genes to have a disorder; skips generations

Carrier

Heterozygous individuals that carry, but do not have the disorder

Autosomal dominant disorder

When the individual only needs one of two alleles to have the disorder; does not skip generations

Boveri-Sutton chromosomal theory of inheritance

The idea that chromosomes are inherited from parents in the genes for traits are located on the chromosomes

Thomas Hunt Morgan

A scientist that studied fruit flies and analyzed certain gene frequencies

Alfred Stutevant

Student of Morgan; figured out crossing over

Recombinant DNA

Genes were crossing over has occurred between them

Linked genes

Genes located on the same chromosome; closer together = likely to be inherited

Unlinked genes

Genes that are located on different chromosomes; further apart = likely to be recombined

Multiple allele traits

Traits that are controlled by several alleles

Incomplete dominance

Both alleles of a gene are partially expressed, resulting in an intermediate phenotype; neither allele is dominant or recessive

Codominance

Several alleles are dominant; both phenotypes are expressed

Antigen

Either sugars or proteins that are attached to various components in the red blood cell membrane, identifying self vs non-self cells

Antibody

Protein produced by your immune system to attack and fight our foreign cells; attached to antigens

Sex linked dominant disorder

Males and females only need one to have it

Y linked disorders

Disorders that are always passed from father to son

Polygenic inheritance

When several genes contribute to a single phenotype

Skin color

Dominant letter = large amount of pigment in the skin; Recessive letter = low amounts of pigment in the skin

Type O

Universal donor; no antigens to react with

type AB

Universal receiver; no antibodies to react with foreign blood

RH factor

More antigens; positive = represents presence of antigens (homologous & heterozygous); Negative = represents no antigens (homologous)

Sex linked gene

Gene that is located on a sex chromosome

Sex linked recessive disorder

Males only need one copy while females need two

Incomplete penetrance

When an individual may have the genotype that won’t produce the phenotype

Variable expressivity

Refers to the range of signs and symptoms that can occur in different people with the same genetic condition

BRCA 1

Occurs when a gene is mutated and produces breast cancer

Marfan syndrome

Affects connective tissue in the body

Pleiotropy

Occurs when a single mutant gene affects two or more distinct and seemingly unrelated traits

Albinism

Skin hair or other physical features that are affected by one mutation

Dwarfism

Lack of growth hormone that leads to abnormally short height

Epistasis

Interaction of two or more gene pairs at different loci influence the same trait, but one of Leo has overwriting effect on the phenotype

pedigree

Family tree that records in traces the occurrence of a trait

Autosomal recessive

Shows a pattern of affected offspring with affected heterozygous parents; cannot be dominant; skips generations

Autosomal dominant

Shows a pattern of affected offspring with affected heterozygous parents; cannot be recessive; doesn’t skip generations

Environmental factors

Influence gene expression and can lead to phenotypic plastic

phenotypic plasticity

Occurs when individuals with the same genotype exhibit different phenotypes in different environments

Hypothesis

Used by scientist to reject or fail to reject statistical hypotheses

Null hypothesis

States there is no relationship between two groups of data

Alternative hypothesis

States that observe results are due to a non-random cause

Chi-square

Used to determine if there is a significant relationship between two groups of data

Huntington’s disease

A progressive and eventually fatal neurological disorder that is caused by a single defective gene on chromosome 4