Science Vocabulary

Science study words

Trait

A characteristic

Inherited trait

A genetically determened characteristic (before birth)

Acquired trait

A characteristic that is learned or received from the environment (develops after birth)

Gene

Basic unit of inheritance (a segment of DNA that contains information about traits)

Allele

The different versions of a gene (1 copy from each parent ex. Skin color, antenna shape)

Dominant allele

A trait that is always visible when 2 copies are present (represented by a capital letter ex. P for purple)

Recessive allele

A trait that is only visible when 2 copies are present (represented by a lowercase letter ex. p for pink)

Punnett Square

A model used to predict the number and varity of genetic combinations

Monohybrid cross

A Punnett square involving only one trait

Phenotype

Physical appearance of an allele or characteristic

Genotype

The genetic make up of an orgainizm (the alliles)

Homozygous

Two of the same alleles (both are dominant or recessive)

Heterozygous

Two different alleles (one dominant and one resessive)

Law of dominance and uniformity

Some alleles are dominant over other alleles for a given gene (1 or more dominant alleles the dominant trait is expressed, 2 or more recessive the recessive trait will be expressed)

Law of Segregation

Indeviduals possesess 2 alleles and a parent passes only 1 allele on to their offspring (if the 2 alleles are identical it's homozygous for the trait but if they are different it's heterozygous)

Incomplete dominance

Occurs when the offspring's phenotype is a blend or somewhere between the 2 parents' phenotypes (the red and white flower make a pink flower or wavey hair)

Codominance

Occurs when both traits appear in the heterozygous offspring. Ex) spotted cows or flowers

Polygenic trait

Occurs when 2 or more genes influence a characteristic (often influenced by environmental factors and distrobution follows a bell-curve pattern ex. skin/ eye color, hight, cancer risk

Dihybrid cross

A Punnett square involving 2 traits

DNA

(Deoxyribonucleic acid): material in the cell that contains genetic information. Parts include sugar (deoxyribose) and phosphate "backbone" and nitrogenous bases (A,T,G and C)

Chargaff's FIRST Rule

There are equal amounts of complementary bases (A always with T and G always pairs with C)

Chargaff's SECOND rule

DNA composition varies from species to species

Mutation

A permenent change in the nucleotide sequence of DNA (the 3 main types include substitution, insertion and deletion)

Substitution

One nucleotide is replaced by another

Insertion

One or more nucleotides are added

Deletion

One or more nucleotides are removed

Codon

A group of 3 nucleotide bases in a gene that code for a single amino acid in a protein

Genome

The complete set of genetic information needed for development and functioning of an organism (the human genome is made up of 23 pairs of chromizones or ~3.2 billion bace pairs)

Clustered regularly interspersed palindromic repeats (CRISPR)

A technology that research scientists use to selectively modify the DNA of living organisms. Adapted from naturally occuring genome editing systems found in bacteria. (components include: Guide RNA, Cas9 enzyme and Cellular repair process)

Guide RNA

In CRISPR it helps identify the target sequence of DNA

Cas9 enzyme

In CRISPR it cuts the DNA at the target sequence

Cellular repair process

In CRISPER it repairs the DNA at the cut location

Gene Therapy

A medical technique that modifies, replaces or repairs DNA to treat, prevent or cure decease. Mechanisms include: Gene replacement, editing and silencing.

Gene replacement

Inserts a healthy copy of a gene into the cells to take over for a missing or faulty gene

Gene editing

Uses CRISPR-Cas9 to cut and fix damaged DNA sequences directly

Gene silencing

Inactivates or blocks a problem gene that is producing harmful proteins.